Variable-tooth gear and self-adaptive three-mode robot finger device

Abstract

The invention relates to the technical field of robot hands, and discloses a variable-tooth gear capable of adjusting the tooth height and simplifying a joint transmission structure, the variable-tooth gear is used for being matched with tooth structures on the two sides of the variable-tooth gear, the variable-tooth gear comprises a gear shell, a rotating structure and a gear tooth assembly, a containing cavity is formed in the gear shell, and a plurality of through holes communicating with the containing cavity are formed in the annular side of the gear shell at intervals; the rotating structure is contained in the containing cavity and can rotate around the center of the containing cavity, and the rotating structure comprises a near hole part close to the through hole and a far hole part back to the near hole part and connected with the near hole part; the gear tooth assembly comprises a plurality of gear teeth which slidably penetrate through the through holes in a one-to-one correspondence mode and can be close to or away from the rotating center of the rotating structure. The rotating structure rotates under the action of external force, so that the gear teeth matched with the near hole part extend in the through hole in the direction away from the rotating center of the rotating structure, and the gear teeth matched with the far hole part retract in the through hole in the direction close to the rotating center of the rotating structure. The invention further discloses a self-adaptive three-mode robot finger device comprising the variable-tooth gear.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of robot hand, in particular to a variable-tooth gear and a self-adaptive three-mode robot finger device. BACKGROUND

[0002] Under-actuated robot hand refers to a robot hand with the number of motors less than the number of joints, which has self-adaptive grasping function and can adapt to grasping of various objects in different scenarios. It has the advantages of stable and accurate grasping, simple device, low cost, small quality and volume, etc. and is widely used in industrial, agricultural and service robots or as a prosthetic hand for the disabled. Among them, the under-actuated robot hand with two degrees of freedom mainly includes two basic working modes of coupled grasping and self-adaptive grasping, and a composite working mode composed of the basic working modes. The coupled grasping mode refers to the rotation of the two joints of the robot hand at a certain ratio or varying ratio, which is specifically divided into forward coupled grasping (referred to as coupled grasping) and reverse coupled grasping. The forward coupled grasping is suitable for the scene of grasping small objects with the end finger segment. The reverse coupled grasping mode is widely used in the same ratio grasping mode and is commonly known as parallel clamping coupled grasping mode (referred to as parallel clamping grasping). The self-adaptive grasping is suitable for enveloping object grasping (force grasping). The composite working mode includes two modes of coupled grasping followed by self-adaptive grasping (coupled self-adaptive grasping mode or coupled self-grasping mode) and parallel clamping followed by self-adaptive grasping (parallel clamping self-adaptive grasping mode or parallel self-grasping mode). Among them, the coupled self-grasping mode has more human-like characteristics, and the pinching effect at the end is easy to achieve. The parallel self-grasping mode has two parallel opening and closing end finger segments, which is suitable for parallel pinching of thin sheet objects or objects with two parallel faces in industry. In actual application, when grasping different objects, the robot hand is often required to have multiple grasping modes and be able to freely switch between different composite modes and basic modes, so as to expand the grasping range of the robot hand, improve its adaptability, and reduce the control difficulty and manufacturing and use cost.

[0003] Chinese invention patent application (CN 108481354 A) discloses a disc-tooth switching multi-mode fusion self-adaptive robot finger device, which includes a base, a first finger segment, a second finger segment, a proximal joint shaft, a distal joint shaft, a first motor and a first transmission mechanism. It can realize the switching of coupled and parallel clamping modes in the direct self-adaptive grasping mode, and can also be locked to enhance grasping. The device uses gear transmission to realize the cooperation between the first joint and the second joint. The gear used is a fixed-tooth gear. During the rotation of the gear, it is always matched with other tooth structures. In order to realize the switching of direction and corresponding action of the robot hand in two opposite directions, multiple sets of gears and pressing blocks need to be configured to realize the switching of direction and corresponding action. The overall structure is bulky and complex, and the assembly work is large. SUMMARY

[0004] Based on this, it is necessary to provide a variable tooth gear and an adaptive three-mode robot finger device which can adjust the tooth height and simplify the joint transmission structure.

[0005] A variable tooth gear for cooperating with tooth structures on both sides thereof, comprising a gear housing, a rotating structure and a gear tooth assembly, the gear housing is provided with a cavity, a plurality of through holes are provided on the ring side of the gear housing and are in communication with the cavity; the rotating structure is accommodated in the cavity and can rotate around the center of the cavity, the rotating structure comprises a near-hole part close to the through hole, a far-hole part opposite to the near-hole part and connected with the near-hole part; the gear tooth assembly comprises a plurality of gear teeth which are slid through the through holes one by one and can be close to or away from the rotating center of the rotating structure; under the action of an external force, the rotating structure rotates, so that the gear tooth cooperating with the near-hole part is elongated in the through hole in the direction away from the rotating center of the rotating structure, and the gear tooth cooperating with the far-hole part is retracted in the through hole in the direction close to the rotating center of the rotating structure.

[0006] In one of the embodiments, the rotating structure is a cam, the near-hole part is a convex part of the cam, and the far-hole part is an arc part of the cam; the rotating structure is made of a magnetic material, or the surface of the rotating structure is provided with a magnetic layer made of a magnetic material; the gear tooth is made of a material that can be magnetically attracted, or the surface of the gear tooth close to the rotating structure is provided with an adsorption layer made of a material that can be magnetically attracted.

[0007] In one of the embodiments, the rotating structure is a cam, the near-hole part is a convex part of the cam, and the far-hole part is an arc part of the cam; the variable tooth gear further comprises a plurality of springs installed on the gear teeth one by one, one end of the spring is limitedly matched with the part of the gear tooth close to the rotating structure, and the other end of the spring abuts against the inner edge of the through hole.

[0008] In one of the embodiments, one rotating structure is rotatably arranged in the cavity; or two rotating structures are rotatably arranged in the cavity and are distributed along the axial direction of the gear housing, and the two rotating structures are arranged at an included angle.

[0009] In one of the embodiments, the rotating structure is a cam, the near-hole part is a convex part of the cam, and the far-hole part is an arc part of the cam; one side of the rotating structure is provided with a non-circular ring-shaped sliding groove which is adapted to the contour shape of the rotating structure, and the end of the gear tooth close to the rotating structure is fixed with a limiting protrusion which is inserted into the non-circular ring-shaped sliding groove and can slide along the inner wall of the non-circular ring-shaped sliding groove.

[0010] In one of the embodiments, the rotating structure comprises a disc or a ring rotatable around the center of the cavity, a connecting column eccentrically fixed on the disc or the ring, and the variable-tooth gear further comprises a plurality of connecting rods sequentially sleeved on the connecting column along the axial direction of the connecting column and corresponding to each tooth respectively, one end of the connecting rod being rotatably connected with the connecting column and the other end of the connecting rod being rotatably connected with the tooth.

[0011] In one of the embodiments, a first motor for driving the rotating structure to rotate is arranged in the cavity, or an arc-shaped guide hole is formed on the gear housing and communicates with the cavity and penetrates through the outer surface of the gear housing, and a gripping part is fixed on the rotating structure and extends out of the arc-shaped guide hole.

[0012] The application further discloses a self-adapting three-mode robot finger device comprising the variable-tooth gear and further comprising a base, a second motor fixed on the base, a first finger segment rotatable in a vertical plane under the driving of the second motor and installed on the top of the base, a rack slider slidingly inserted into the first finger segment in a horizontal direction and limitedly matched with the first finger segment in a vertical direction, a third gear accommodated in the first finger segment and rotatably connected with the first finger segment, a connecting rod gear meshed with the third gear and rotatable relative to the first finger segment, a limiting block movably arranged on the base to limit the rotation of the connecting rod gear in a preset direction, a second finger segment located above the first finger segment and rotatably connected with the first finger segment, a mounting groove being formed in the lower part of the rack slider, a first rack structure being arranged on the upper wall of the mounting groove, a second rack structure being arranged on the lower wall of the mounting groove, a third rack structure being arranged on the top of the rack slider, a gear structure being arranged on the lower part of the second finger segment and meshed with the third rack structure, and the variable-tooth gear being accommodated in the mounting groove and coaxially rotatable with the third gear. The rotating structure is rotated under the action of an external force, so that the teeth of the variable-tooth gear are meshed with the first rack structure and push the rack slider to move in a first direction, so that the second finger segment is rotated relative to the first finger segment, or the teeth of the variable-tooth gear are meshed with the second rack structure and push the rack slider to move in a second direction, so that the second finger segment is reversely rotated relative to the first finger segment, or the teeth of the variable-tooth gear are separated from the first rack structure and the second rack structure.

[0013] In one of the embodiments, the adaptive three-mode robot finger device further comprises a transmission structure, a first gear and a second gear located outside the base, the second motor is fixed in the base and extends in the vertical direction, the transmission structure comprises a worm gear located above the second motor and drivingly connected with the motor shaft of the second motor, a worm wheel located above the worm gear and meshing with the worm gear, the worm wheel is vertically arranged with the worm gear, the worm wheel is connected with the first gear through a first rotating shaft penetrating through the base, and the worm wheel rotates coaxially with the first gear, the second gear meshes with the first gear, and the second gear is connected with the first finger segment through a second rotating shaft to drive the first finger segment to rotate.

[0014] In one of the embodiments, the limiting block is rotatably arranged on the base, and a first elastic member is arranged between the limiting block and the connecting rod gear, the limiting block comprises a rotating part rotatably connected with the base, and a limiting part fixed at the end of the rotating part, the width of the limiting part is greater than that of the rotating part, a first limiting step is formed on one side of the limiting part adjacent to the rotating part, and a second limiting step is formed on the other side of the limiting part adjacent to the rotating part; or the limiting block is a slide bolt slidably inserted into the side surface of the base. A limiting member is fixed in the first finger segment, a guide through hole is formed in the rack block between the first rack structure and the third rack structure, and the limiting member penetrates through the guide through hole and is in sliding cooperation with the rack block; a guide limiting hole is formed in the top of the first finger segment for the second finger segment to pass through and limit the rotation range of the second finger segment.

[0015] The variable tooth gear and the adaptive three-mode robot finger device are implemented, the variable tooth gear is arranged, each tooth is extended out of the through hole or retracted into the through hole under the driving of the rotating structure, the shape and the tooth height of the tooth on the gear can be changed, the gear can be matched with the tooth structure on both sides according to the requirement, and then the related mechanism connected with the tooth structure is driven to move, so that the mechanism moves in two opposite directions, thus, the switching of the mechanism in different directions and corresponding actions can be realized by using one variable tooth gear, without the need of arranging multiple gears and pressure blocks to work cooperatively, the transmission structure of the joint of the robot finger device is simplified, and the assembly work amount of the robot finger device is reduced; the adaptive three-mode robot finger device adopting the variable tooth gear can realize the switching of the flat clamping underdrive adaptive gripping, the coupling underdrive adaptive gripping and the general underdrive adaptive gripping of the robot finger device by driving the second motor and adjusting the shape of the variable tooth gear and the limiting block, the gripping range of the robot hand is expanded, the adaptability is improved, the number of gears is reduced, and the assembly work amount of the robot finger device is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a structural schematic view of the variable tooth gear in one of the embodiments of the present application. Figure 2For Figure 1 Structure diagram of the variable tooth gear in another embodiment of the present application after removing a side plate; Figure 3 Structure diagram of the variable tooth gear in another embodiment of the present application after removing a side plate; Figure 4 For Figure 3 Structure diagram of the variable tooth gear in another embodiment of the present application after removing a side plate; Figure 5 For Figure 3 Structure diagram of the variable tooth gear in another embodiment of the present application after removing a side plate; Figure 6 Structure diagram of the variable tooth gear in another embodiment of the present application after removing a side plate; Figure 7 Structure diagram of the variable tooth gear in another embodiment of the present application after removing a side plate; Figure 8 Structure diagram of the adaptive three-mode robot finger device in coupling adaptive mode in one embodiment of the present application; Figure 9 Structure diagram of the adaptive three-mode robot finger device in coupling adaptive mode in one embodiment of the present application; Figure 10 Structure diagram of the adaptive three-mode robot finger device in coupling adaptive mode in one embodiment of the present application; Figure 11 Structure diagram of the adaptive three-mode robot finger device in coupling adaptive mode in one embodiment of the present application; Figure 12 Structure diagram of the adaptive three-mode robot finger device in coupling adaptive mode in one embodiment of the present application; Figure 13 Structure diagram of the adaptive three-mode robot finger device in coupling adaptive mode in one embodiment of the present application; Figure 14 Structure diagram of the adaptive three-mode robot finger device in coupling adaptive mode in one embodiment of the present application; DETAILED DESCRIPTION

[0017] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be implemented in many different ways other than those described herein, and those skilled in the art can make similar improvements without departing from the scope of the present application, and therefore the present application is not limited to the specific embodiments disclosed below.

[0018] The application discloses a variable tooth gear 100 which can adjust tooth height and simplify gear transmission structure. The variable tooth gear 100 can be used to replace the common missing tooth gear (i.e. incomplete gear or intermittent gear) on the market, so that the gear periodically drives the tooth structure matched with the gear in the rotating condition, realizes intermittent movement of the tooth structure, and can also be used in some special occasions, such as the gear without external rotating driving mechanism, the gear itself in the non-rotating condition, the internal driving part of the variable tooth gear 100 or manual operation, so that the gear tooth on the variable tooth gear 100 periodically moves to drive other components matched with the variable tooth gear 100 to move (such as periodically lifting other components in a small range to meet the mechanical transmission requirement). Of course, in actual application, the user can select the variable tooth gear 100 of the present application as a transmission structure or a driving structure according to the specific use scene and transmission requirement, and the application scene is not limited to the robot finger device of the application, and details are not described herein.

[0019] Please combine Figure 1 With Figure 2, the variable tooth gear 100 is used to cooperate with the tooth structure on both sides of the variable tooth gear 100 to drive the components with the tooth structure on both sides of the variable tooth gear 100 to rotate or translate during the rotation of the variable tooth gear 100, or to drive the components with the tooth structure to lift through the periodic movement of the gear teeth of the variable tooth gear 100 when the variable tooth gear 100 is stationary. Specifically, the variable tooth gear 100 of the embodiment includes a gear housing 110, a rotating structure 120, and a gear tooth assembly. The gear housing 110 has a cavity 111 inside. The gear housing 110 includes an annular enclosure, two side plates located on the two opposite sides of the annular enclosure and fixedly connected with the annular enclosure. The outer contour shape of the side plate is adapted to the shape of the area surrounded by the annular enclosure. The annular enclosure and the two side plates together form the cavity 111. In actual application, the annular enclosure can be a regular polygon ring structure or a circular ring structure. Preferably, the annular enclosure is a circular ring structure, and the side plate is a circular plate structure. The entire gear housing 110 has a hollow cylindrical structure to avoid collision between the gear housing 110 and external devices during the rotation of the variable tooth gear 100. A plurality of through holes 112 are arranged on the ring side of the gear housing 110 and communicate with the cavity 111. The through holes 112 are used as channels for the gear teeth to extend or retract on the gear housing 110. The rotating structure 120 is received in the cavity 111 and can rotate around the center of the cavity 111. That is, the variable tooth gear 100 further includes a central shaft 130 penetrating the rotating structure 120 and rotatingly cooperating with the gear housing 110 to define the rotation of the rotating structure 120 and provide the rotation center of the rotating structure 120. The rotating structure 120 includes a near-hole portion close to the through hole 112 and a far-hole portion opposite to the near-hole portion and connected with the near-hole portion. The rotating structure 120 can be rotated by arranging a driving motor in the gear housing 110, or the rotating structure 120 can be manually driven to rotate by arranging corresponding gripping components. The gear tooth assembly includes a plurality of gear teeth 140 which are slid through the through holes 112 one by one and can approach or move away from the rotation center of the rotating structure 120. The rotating structure 120 rotates under the action of external force to make the gear teeth 140 cooperating with the near-hole portion extend in the through hole 112 in the direction away from the rotation center of the rotating structure 120, and make the gear teeth 140 cooperating with the far-hole portion retract in the through hole 112 in the direction approaching the rotation center of the rotating structure 120. In other words, in this scheme, since one end of each gear tooth 140 located in the cavity 111 cooperates with the rotating structure 120, the rotating structure 120 will periodically extend and retract the gear tooth 140 in the corresponding through hole 112 during the rotation of the rotating structure 120 relative to the gear tooth 140. According to different application scenarios of the variable tooth gear 100, the rotating structure 120 can continuously rotate during the use of the variable tooth gear 100, so that the tooth height of each gear tooth 140 on the variable tooth gear 100 changes in real time. The rotating structure 120 can also intermittently rotate during the use of the variable tooth gear 100, so that the shape of the gear tooth 140 of the variable tooth gear 100 remains unchanged for a period of time to meet different application scenarios of the variable tooth gear 100.

[0020] Please further combine Figure 1 and Figure 2 , the rotating structure 120 is a cam, the near hole part is a convex part of the cam, the far hole part is an arc part of the cam, and the matching part of the convex part and the arc part is smoothly transitioned to avoid the problem of sudden increase or decrease of the tooth height of the gear tooth 140 during the stretching and contraction of the gear tooth 140 at the through hole 112, so as to ensure the stability of the transmission of the variable tooth gear 100. The rotating structure 120 is made of a magnetic material, or the surface of the rotating structure 120 is provided with a magnetic layer made of a magnetic material; the gear tooth 140 is made of a material that can be magnetically attracted, or the surface of the gear tooth 140 near one end of the rotating structure 120 is provided with an adsorption layer made of a material that can be magnetically attracted. In this way, when the rotating structure 120 rotates, each part on the ring side surface of the rotating structure 120 is matched with the gear tooth 140 in turn. Taking a certain gear tooth 140 as an example, when the gear tooth 140 is matched with the near hole part (convex part) by magnetic attraction, the distance from the gear tooth 140 to the rotation center of the rotating structure 120 reaches a maximum value, and the elongation of the gear tooth 140 is maximum. When the gear tooth 140 is matched with the far hole part (arc part) by magnetic attraction, the distance from the gear tooth 140 to the rotation center of the rotating structure 120 reaches a minimum value, and the elongation of the gear tooth 140 is minimum. When the part between the near hole part and the far hole part on the rotating structure 120 is matched with the gear tooth 140 by magnetic attraction, the elongation of the gear tooth 140 is between the maximum value and the minimum value. Thus, through the magnetic attraction connection between the gear tooth 140 and the rotating structure 120, the extrusion of the ring side surface of the rotating structure 120 to the gear tooth 140, and the rotation driving of the rotating structure 120, the adjustment of the tooth height of the gear tooth 140 is realized. Further, to avoid the gear tooth 140 from falling out of the through hole 112, a limiting convex part is arranged on the gear tooth 140. The position of the limiting convex part needs to meet that when the gear tooth 140 is matched with the convex part of the rotating structure 120 and the elongation of the gear tooth 140 reaches a maximum value, the limiting convex part is limited and abuts against the inner edge of the through hole 112 (i.e. the communication part of the through hole 112 and the cavity 111) to prevent the gear tooth 140 from falling off. Preferably, the side of the gear tooth 140 that is matched with the rotating structure 120 by magnetic attraction is an arc surface, so as to reduce the abrasion of the gear tooth 140 during the rotation of the rotating structure 120.

[0021] Please combine Figures 3-5, another embodiment, the rotating structure 120 is a cam, the near hole part is the convex part of the cam, the far hole part is the circular arc part of the cam, and the matching part of the convex part and the circular arc part is smoothly transitioned to avoid the problem of sudden increase or decrease in the height of the gear teeth 140 during the stretching and contraction of the gear teeth 140 at the through hole 112, so as to ensure the stability of the variable-tooth gear transmission. The variable-tooth gear further comprises a plurality of springs 150 installed one-to-one on each gear tooth 140, one end of the spring 150 is limitedly matched with the part of the gear tooth 140 adjacent to the rotating structure 120, and the other end of the spring 150 is in abutment with the inner side edge of the through hole 112 (i.e. the outer diameter of the spring 150 is greater than the width of the through hole 112, so that the spring 150 can abut against the gear housing 110). Further, in this embodiment, the gear tooth 140 comprises a body 141 in the shape of U or n, at least one limiting rod 142 fixedly connected with the body 141, the body 141 comprises two vertical parts oppositely arranged, a horizontal part fixedly connected with the same end of the two vertical parts, the limiting rod 142 is located between the two vertical parts and fixedly connected with the horizontal part, and the limiting rod 142 is parallel to the vertical part, the end of the limiting rod 142 is fixedly connected with a limiting head 143, and the length of the limiting rod 142 is greater than the length of the vertical part, the spring 150 is sleeved on the limiting rod 142 and abuts against the limiting head 143 and the inner side edge of the through hole 112 respectively. In this way, when the gear tooth 140 is matched with the far hole part of the rotating structure 120, the spring 150 is elongated, so that the limiting head 143 abuts against the far hole part of the rotating structure 120, and at the same time the gear tooth 140 is retracted under the driving of the spring 150, and the height of the gear tooth 140 protruding out of the through hole 112 is reduced; with the rotation of the rotating structure 120, the gear tooth 140 contacts the ring side surface of the rotating structure 120, the spring 150 is compressed under the joint extrusion of the limiting head 143 and the inner side edge of the through hole 112 (i.e. the gear housing 110), so that the height of the gear tooth 140 protruding out of the through hole 112 is increased, until the gear tooth 140 is matched with the near hole part, the compression amount of the spring 150 reaches the maximum, and the height of the gear tooth 140 protruding out of the through hole 112 reaches the maximum value. During this process, the spring 150 provides pre-tightening force and restoring force, so that the gear tooth 140 continuously abuts against the rotating structure 120. In this embodiment, when only one limiting rod 142 is arranged in the body 141, the limiting rod 142 is fixedly connected with the middle part of the horizontal part, and when the number of limiting rods 142 is greater than 1, the plurality of limiting rods 142 are symmetrically arranged with the middle part of the horizontal part as the center, so that the force acting on the gear tooth 140 during the stretching and contraction of the spring 150 tends to be uniform, and the shaking of the gear tooth 140 during the stretching and contraction is reduced.

[0022] In the above two embodiments, the cavity 111 is provided with a rotating structure 120; or the cavity 111 is provided with two rotating structures 120 which are distributed along the axial direction of the gear housing 110 and are provided with an included angle. Preferably, the cavity 111 is provided with two rotating structures 120 which are distributed along the axial direction of the gear housing 110, and the two rotating structures 120 can be driven by the same driving motor to rotate synchronously, or a gripping part which connects the two rotating structures 120 simultaneously is provided to manually drive the two rotating structures 120 to rotate synchronously, or the rotation of the two rotating structures 120 can be controlled independently. When the included angle of the two rotating structures 120 is 0°, the gear teeth 140 can be supported stably by the two rotating structures 120, and the shaking of the gear teeth 140 can be reduced. When the included angle of the two rotating structures 120 is greater than 0°, the two rotating structures 120 can extrude the hole part to form two protruding teeth on the ring side of the gear, so that the gear can drive two mechanisms on its two sides to move simultaneously. For example, when the included angle of the two rotating structures 120 is 180°, two protruding teeth are formed on the two opposite sides of the gear, and a rack is arranged on each side of the gear, so that the gear can drive two independent parts on its two opposite sides simultaneously.

[0023] Please combine Figure 6In another embodiment, the rotating structure 120 is a cam, the proximal hole portion is a convex portion of the cam, and the distal hole portion is an arc portion of the cam. The transition between the convex portion and the arc portion is smooth to avoid the problem of sudden increase or decrease in the tooth height of the gear tooth 140 during the extension and retraction of the gear tooth 140 through the through hole 112, thereby ensuring the stability of the variable tooth gear transmission. One side of the rotating structure 120 is provided with a non-circular ring-shaped sliding groove 121 that is adapted to the profile of the rotating structure 120. The gear tooth 140 is fixed with a limiting protrusion 144 adjacent to one end of the gear tooth 140, which is inserted into the non-circular ring-shaped sliding groove 121 and can slide along the inner wall of the non-circular ring-shaped sliding groove 121. Preferably, in this embodiment, the two opposite sides of the rotating structure 120 are each provided with a non-circular ring-shaped sliding groove 121, and the gear tooth 140 has a U-shaped structure, including two vertically arranged vertical arms and a horizontal arm fixedly connected to the same end of the two vertical arms. The inner side of the end of each vertical arm is provided with a limiting protrusion 144, and the two limiting protrusions 144 are respectively embedded in the non-circular ring-shaped sliding grooves 121 on the two sides of the rotating structure 120, i.e., the entire gear tooth 140 has a C-shaped structure. In this way, the gear tooth 140 is locked on the rotating structure 120 by the limiting protrusions 144, and the continuous sliding of the gear tooth 140 along the non-circular ring-shaped sliding groove 121 is ensured. During the rotation of the rotating structure 120, different parts of the inner wall of the non-circular ring-shaped sliding groove 121 cooperate with the limiting protrusions 144, thereby pulling the gear tooth 140 close to the center of rotation of the rotating structure 120 by the limiting protrusions 144, or pushing the gear tooth 140 away from the center of rotation of the rotating structure 120 by the limiting protrusions 144, thereby achieving the extension and retraction of the gear tooth 140. Of course, the gear tooth 140 can also be a sheet structure inserted into the cavity 111 through the through hole 112, and only one non-circular ring-shaped sliding groove 121 is provided on one side of the rotating structure 120, and a limiting protrusion 144 is fixed on the gear tooth 140 of the sheet structure, so that the limiting protrusion 144 is embedded in the non-circular ring-shaped sliding groove 121.

[0024] Please refer to Figure 7In another embodiment, the rotating structure 120 comprises a disc or a ring 122 rotatable around the center of the cavity 111, a connecting column 123 eccentrically fixed on the disc or the ring 122, and the variable tooth gear further comprises a plurality of connecting rods 124 sequentially sleeved on the connecting column 123 along the axial direction of the connecting column 123 and corresponding to each tooth 140 one by one, one end of the connecting rod 124 is rotatably connected with the connecting column 123, and the other end of the connecting rod 124 is rotatably connected with the tooth 140. In this embodiment, the disc or the ring 122, the connecting column 123 and the connecting rod 124 play the same role as the cam in the previous embodiment. When the disc or the ring 122 is rotated to the position where the connecting column 123 is located at the far end of the tooth 140, the connecting rod 124 connected with the tooth 140 constitutes the far hole part of the rotating structure 120, and when the disc or the ring 122 is rotated to the position where the connecting column 123 is located at the near end of the tooth 140, the connecting rod 124 connected with the tooth 140 constitutes the near hole part of the rotating structure 120. That is, during the rotation of the disc or the ring 122, according to the different angles of rotation of the connecting column 123 and the different distances of the connecting rod 124 being pulled, the positions of the near hole part and the far hole part of the rotating structure 120 are constantly changing, and the same connecting rod 124 constantly changes between the near hole part, the far hole part and the position between the near hole part and the far hole part of the rotating structure 120. In this way, the disc or the ring and the connecting column 123 form a rocker, and the rotating structure 120 actually forms a rocker driving structure, so that through the rotation of the rocker, the connecting rod 124 is driven to swing, and then the tooth 140 moves in a straight line direction under the limitation of the inner wall of the through hole 112, so as to realize the extension and contraction of the tooth 140.

[0025] In the above different variant structures of the variable tooth gear 100, the number of the teeth 140 can be 20 teeth, 30 teeth, 40 teeth, etc. In actual production, according to the transmission ratio requirement of the device where the variable tooth gear 100 is located, the size requirement of the transmission structure and the smoothness requirement, etc., the appropriate number of the teeth 140 can be selected, and the specific number of the teeth 140 is not within the protection scope of the present scheme.

[0026] In the above different variant structures of the variable tooth gear 100, the cavity 111 is provided with a first motor for driving the rotating structure 120 to rotate, so that the rotating structure 120 can be driven to rotate by the first motor to automatically adjust the tooth height of the variable tooth gear 100; or the gear housing 110 is provided with an arc-shaped guide hole 113 which is in communication with the cavity 111 and penetrates through the outer surface of the gear housing 110, and the rotating structure 120 is fixed with a gripping portion 125 which extends out of the arc-shaped guide hole 113, so that the gripping portion 125 can be turned together with the rotating structure 120 by the operating personnel to manually drive the rotating structure 120. In the present embodiment, the arc-shaped guide hole 113 is used to limit the rotating path of the gripping portion 125 and the rotating angle of the rotating structure 120. In addition, the gear housing 110 of the variable tooth gear 100 is also provided with connecting shafts on two opposite sides, which are used to provide mounting portions of the variable tooth gear 100 so that the variable tooth gear 100 is fixed or rotatably arranged on an external member.

[0027] In addition, please refer to Figures 1-2 and Figures 8-14The application further discloses a self-adaptive three-mode robot finger device which comprises the variable-tooth gear 100, a base 200, a second motor 300 fixed on the base 200, a first finger segment 400 installed on the top of the base 200 and rotating in a vertical plane under the driving of the second motor 300, a rack slider 500 slidingly inserted into the first finger segment 400 and limitedly matched with the first finger segment 400 in a vertical direction, a third gear 600 accommodated in the first finger segment 400 and rotationally connected with the first finger segment 400, a connecting rod gear 700 meshed with the third gear 600 and rotatable relative to the first finger segment 400, a limiting block 800 movably arranged on the base 200 to limit the rotation of the connecting rod gear 700 in a preset direction, and a second finger segment 900 located above the first finger segment 400 and rotationally connected with the first finger segment 400. The rack slider 500 is limitedly matched with the first finger segment 400 in the vertical direction, so that the rack slider 500 is prevented from sliding off or falling from the first finger segment 400 in the vertical direction. In the embodiment, a mounting groove 510 is formed in the lower part of the rack slider 500, a first rack structure 520 is arranged on the upper wall of the mounting groove 510, a second rack structure 530 is arranged on the lower wall of the mounting groove 510, a third rack structure 540 is arranged on the top of the rack slider 500, a gear structure 910 meshed with the third rack structure 540 is arranged on the lower part of the second finger segment 900, the variable-tooth gear 100 is accommodated in the mounting groove 510, and the variable-tooth gear 100 is coaxially rotatable with the third gear 600. The rotating structure 120 rotates under the action of an external force (driven by the first motor or manually rotated) to make the gear teeth 140 of the variable-tooth gear 100 mesh with the first rack structure 520 and push the rack slider 500 to move in a first direction, so that the second finger segment 900 rotates relative to the first finger segment 400; or the gear teeth 140 of the variable-tooth gear 100 mesh with the second rack structure 530 and push the rack slider 500 to move in a second direction, so that the second finger segment 900 reversely rotates relative to the first finger segment 400; or the gear teeth 140 of the variable-tooth gear 100 are separated from the first rack structure 520 and the second rack structure 530.

[0028] The variable-tooth gear 100 with two rotating structures 120 shown in FIG. 2 is applied to the robot finger device, and the action process of the robot finger device in different working modes is described in combination with FIGS. 3-5. Figures 1-2 Figures 8-14

[0029] ​​First, the state of the rotating structure 120 is defined. The proximal hole part (i.e. the convex part of the cam) of the two rotating structures 120 is defined as upward, so that the teeth 140 on the upper part of the variable tooth gear 100 protrude out of the gear housing 110 for a long distance, and the teeth 140 on the left and right sides and lower part of the variable tooth gear 100 are kept in a position almost not protruding out of the gear housing 110 under magnetic attraction, as the upper protruding state of the variable tooth gear 100. The proximal hole part (i.e. the convex part of the cam) of the two rotating structures 120 is defined as respectively facing the left and right sides of the variable tooth gear 100, so that the teeth 140 on the left and right sides of the variable tooth gear 100 protrude out of the gear housing 110 for a long distance, and the teeth 140 on the upper and lower parts of the variable tooth gear 100 are kept in a position almost not protruding out of the gear housing 110 under magnetic attraction, as the middle protruding state of the variable tooth gear 100. The proximal hole part (i.e. the convex part of the cam) of the two rotating structures 120 is defined as downward, so that the teeth 140 on the lower part of the variable tooth gear 100 protrude out of the gear housing 110 for a long distance, and the teeth 140 on the upper and left and right sides of the variable tooth gear 100 are kept in a position almost not protruding out of the gear housing 110 under magnetic attraction, as the lower protruding state of the variable tooth gear 100.

[0030] When the robot finger device is in the coupling adaptive mode, the second motor 300 works and drives the first finger segment 400 to rotate in the vertical plane in the clockwise direction, the limiting block 800 cooperates with the connecting rod gear 700 and limits the rotation of the connecting rod gear 700 in the clockwise direction, so that the connecting rod gear 700 remains not to rotate, at this time, the third gear 600 rotates clockwise around the connecting rod gear 700 under the drive of the first finger segment 400 and meshes with the connecting rod gear 700, and the variable tooth gear 100 rotates coaxially and synchronously with the third gear 600. Adjust the variable tooth gear 100 to the lower protruding state, the teeth 140 of the variable tooth gear 100 mesh with the second rack structure 530, and drive the rack block 500 to move towards the inside of the first finger segment 400, thus, through the meshing of the third rack structure 540 and the gear structure 910 and the limiting cooperation of the second finger segment 900 and the first finger segment 400, the rack block 500 drives the second finger segment 900 to rotate in the clockwise direction with the center of the gear structure 910 as the axis. In this process, by making the first rack structure 520, the second rack structure 530 and the third rack structure 540 of the same specification, the tooth spacing of the variable tooth gear 100 is the same as the tooth spacing of the gear structure 910 of the second finger segment 900, so that when the first finger segment 400 rotates by an angle a relative to the base 200, the second finger segment 900 also rotates by an angle a relative to the first finger segment 400, i.e. the second finger segment 900 rotates by an angle a relative to the base 200.

[0031] When the robot finger device is in the coupling adaptive mode, if the rack slider 500 touches the object to be grabbed and the robot finger device continues to move, under the extrusion of the object to be grabbed, the rack slider 500 accelerates to move towards the inside of the first finger segment 400, thereby driving the second finger segment 900 and the variable gear 100 to accelerate rotation, at the same time, the third gear 600 accelerates rotation and drives the connecting rod gear 700 to rotate in the counterclockwise direction (the limiting block 800 only limits the rotation of the connecting rod gear 700 in the clockwise direction), until the maximum movement limit is reached, so as to grab the object by the first finger segment 400 and the second finger segment 900.

[0032] When the robot finger device is in the general adaptive mode, the robot finger device is restored to the initial state (the base 200, the first finger segment 400 and the second finger segment 900 are located on the same vertical line), the limiting block 800 is released from the constraint of the connecting rod gear 700, and the variable gear 100 is adjusted to the middle protruding state. By driving the first finger segment 400 to rotate by the second motor 300, the third gear 600 rotates synchronously with the variable gear 100, and since the variable gear 100 is in the middle protruding state, the teeth 140 of the variable gear 100 do not contact the first rack structure 520 and the second rack structure 530, so the variable gear 100 cannot affect the rack slider 500, so that the rack slider 500 remains stationary before touching the object (when the first finger segment 400 rotates clockwise, the rack slider 500 rotates synchronously with the first finger segment 400, the third gear 600 and the variable gear 100, so that the variable gear 100 and the rack slider 500 remain relatively stationary). Before the movement process reaches the maximum movement limit, if the rack slider 500 touches the object to be grabbed and the robot finger device continues to move, under the extrusion of the object to be grabbed, the rack slider 500 will accelerate to move towards the inside of the first finger segment 400, thereby driving the second finger segment 900 to accelerate rotation, until the maximum movement limit is reached.

[0033] When the robot finger device is in the flat clamping adaptive mode, the robot finger device is restored to the initial state (the base 200, the first finger segment 400 and the second finger segment 900 are located on the same vertical line), the limiting block 800 is matched with the connecting rod gear 700 and the rotation of the connecting rod gear 700 in the counterclockwise direction is limited, the variable tooth gear 100 is adjusted to the upper protruding state, and the variable tooth gear 100 is meshed with the first rack structure 520 of the rack slider 500. When the variable tooth gear 100 rotates clockwise following the third gear 600, the rack slider 500 is driven to move outward of the first finger segment 400 through the meshing of the variable tooth gear 100 and the first rack structure 520, so that the second finger segment 900 is driven to rotate in the counterclockwise direction with the gear structure 910 below the second finger segment 900 as the axis. Since the first rack structure 520, the second rack structure 530 and the third rack structure 540 are of the same specification, the tooth spacing of the variable tooth gear 100 is the same as the tooth spacing of the gear structure 910 of the second finger segment 900, when the first finger segment 400 rotates by an angle a relative to the base 200, the second finger segment 900 rotates by an angle a relative to the first finger segment 400, at this time, the second finger segment 900 is parallel to the base 200. Before the movement reaches the maximum movement limit, if the rack slider 500 touches the grabbed object and the robot finger device continues to move, under the extrusion of the grabbed object, the rack slider 500 accelerates to move inward of the first finger segment 400, thereby driving the second finger segment 900 and the variable tooth gear 100 to accelerate rotation, at the same time, the third gear 600 accelerates rotation, and the connecting rod gear 700 rotates in the clockwise direction (the limiting block 800 only limits the rotation of the connecting rod gear 700 in the counterclockwise direction), until the maximum movement limit is reached, so as to grab the object by the first finger segment 400 and the second finger segment 900.

[0034] In the above three modes, the parallel clamping mode can use the end finger end to clamp the object, or support the object from the inside to clamp the hollow object; the coupled clamping mode can achieve better clamping of the object, or use the end finger end to pinch the object, and the degree of personification is higher; the general clamping mode (non-composite / basic mode) can conveniently adjust the finger posture, and can also be used for teaching demonstration and adaptive function test. In addition to the above functions, the three modes can all achieve indirect adaptive clamping function.

[0035] After the movement of the above three modes is completed, the second motor 300 reversely rotates and drives the first finger segment 400 to rotate counterclockwise until the object is completely separated from the rack flower, and the limiting block 800 and the connecting rod gear 700 are restored to the initial state (the rod body of the connecting rod gear 700 is horizontal, and the limiting hole limits the rotation of the connecting rod gear 700 in the clockwise direction), and the second motor 300 continues to operate to restore the robot finger device to the initial state.

[0036] It should be noted that the second motor 300 can directly drive the first finger segment 400 to rotate, that is, the motor shaft of the second motor 300 extends in the horizontal direction, and the second finger segment 400 is directly driven to rotate by the motor shaft of the second motor 300, or the second motor 300 can be accommodated in the base 200 and the motor shaft of the second motor 300 extends in the vertical direction, and the drive between the motor shaft of the second motor 300 and the first finger segment 400 is realized by setting a corresponding transmission unit. Specifically, in the present embodiment, the adaptive three-mode robotic finger device further comprises a transmission structure, a first gear 210 and a second gear 220 located outside the base 200, the second motor 300 is fixed in the base 200 and extends in the vertical direction, the transmission structure comprises a worm 230 located above the second motor 300 and drivingly connected with the motor shaft of the second motor 300, a worm wheel 240 located above the worm 230 and meshing with the worm 230, the worm wheel 240 is perpendicular to the worm 230, the worm wheel 240 is connected with the first gear 210 through a first rotating shaft 250 penetrating the base 200, and the worm wheel 240 rotates coaxially with the first gear 210, the second gear 220 is located above the first gear 210 and meshes with the first gear 210, and the second gear 220 is connected with the first finger segment 400 through a second rotating shaft 260 to drive the first finger segment 400 to rotate. In this way, through the cooperation of the worm wheel 240 and the worm 230, the rotation of the motor shaft of the second motor 300 in the vertical direction in the horizontal plane can be converted into the rotation of the second rotating shaft 260 in the vertical plane, thereby driving the first finger segment 400 to rotate in the vertical plane and realizing the change of motion. In addition, the use of the worm wheel 240 and the worm 230 makes the robotic finger device have a self-locking function when the lead angle (γ) of the worm 230 is less than or equal to the equivalent friction angle (ρ), and the transmission ratio is large, which is beneficial to reduce the rotation speed of the robotic finger and realize more precise grabbing. Through the meshing of the first gear 210 and the second gear 220, in actual application, the tooth number ratio of the first gear 210 and the second gear 220 can be adjusted, and then the transmission ratio between the second motor 300 and the first finger segment 400 is adjusted, so that the rotation speed of the first finger segment 400 meets the design requirements.

[0037] Further, in an embodiment, the limiting block 800 is rotatably arranged on the base 200, and a first elastic member is arranged between the limiting block 800 and the connecting rod gear 700. The limiting block 800 includes a rotating part rotatably connected to the base 200, and a limiting part fixed at the end of the rotating part. The width of the limiting part is greater than that of the rotating part. A first limiting step is formed on one side of the limiting part adjacent to the rotating part, and a second limiting step is formed on the other side of the limiting part adjacent to the rotating part. When the connecting rod gear 700 is arranged horizontally (the rod body of the connecting rod gear 700 extends horizontally), the limiting block 800 is rotated clockwise or counterclockwise, so that the first limiting step of the limiting block 800 abuts against the upper surface of the rod body of the connecting rod gear 700 to limit the rotation of the connecting rod gear 700 in the clockwise direction, and the second limiting step of the limiting block 800 abuts against the lower surface of the rod body of the connecting rod gear 700 to limit the rotation of the connecting rod gear 700 in the counterclockwise direction. By arranging the first elastic member (such as a spring, elastic strip or rubber band) between the limiting block 800 and the connecting rod gear 700, when the connecting rod gear 700 is rotated under the driving of the third gear 600, the first elastic member is deformed and elongated. When the second motor 300 is reversely rotated to rotate the first finger segment 400 counterclockwise to reset, the first elastic member restores the deformation, so that the object and the rack slider 500 are accelerated to separate until completely separated, and at this time, the connecting rod gear 700 returns to the initial state (the connecting rod gear 700 is arranged horizontally). In another embodiment, the limiting block 800 is a plug slidably inserted into the side surface of the base 200. Thus, when it is necessary to limit the connecting rod gear 700, the plug is inserted into the corresponding hole of the base 200, and the plug abuts against the upper surface or the lower surface of the rod body of the connecting rod gear to limit the rotation of the connecting rod gear 700.

[0038] It should be noted that, in order to realize the fast resetting of the rack slider 500 in the general adaptive mode, the second elastic member 401 (such as a spring, elastic strip or rubber band) is arranged between the inner wall of the first finger segment 400 and the rack slider 500. The second elastic member 401 is fixedly connected to the inner wall of the first finger segment 400 and the side wall of the rack slider 500, respectively, and the deformation direction (i.e. the extension direction) of the second elastic member 401 is the same as the sliding direction of the rack slider 500. Thus, when the robot finger device is reset, the rack slider 500 can be driven by the second elastic member 401 to move fast to the inside of the first finger segment 400, so as to realize the fast resetting of the rack slider 500.

[0039] In an embodiment, the first finger section 400 is internally provided with a limiting piece 410, which is fixedly connected to the two opposite inner side walls of the first finger section 400 and arranged along the width direction of the first finger section 400. The rack slider 500 is provided with a guide through hole 550 between the first rack structure 520 and the third rack structure 540, and the limiting piece 410 passes through the guide through hole 550 and is in sliding cooperation with the rack slider 500. In this way, on the basis of the cooperation of the guide through hole 550 and the limiting piece 410 to limit the sliding path of the rack slider 500, the relative position of the rack slider 500 and the first finger section 400 in the vertical direction is also limited, so as to avoid the rack slider 500 from falling off the first finger section 400 in the vertical direction. The first finger section 400 is provided, above the second rotating shaft 260, with a third rotating shaft 420 in rotational cooperation with the two opposite inner side walls of the first finger section 400, the third rotating shaft 420 is parallel to the second rotating shaft 260, and the third gear wheel 600 and the variable-tooth gear wheel 100 are sleeved on the third rotating shaft 420 and are radially limited by the third rotating shaft 420, so that the third gear wheel 600, the variable-tooth gear wheel 100 and the third rotating shaft 420 can synchronously rotate. The top of the first finger section 400 is provided with a guide limiting hole 430 for the second finger section 900 to pass through and limit the rotation range of the second finger section 900. Preferably, the top of the first finger section 400 is provided with an arc-shaped top shell, and the guide limiting hole 430 is arranged on the arc-shaped top shell and extends along an arc path, so as to limit the rotation range of the second finger section 900. In this embodiment, the first finger section 400 is provided, above the third rack structure 540, with a fourth rotating shaft 440, which is fixedly connected to the two opposite inner side walls of the first finger section 400 and penetrates through the gear structure 910 of the second finger section 900 and is in rotational cooperation with the gear structure 910, so as to limit the second finger section 900.

[0040] It should be noted that in actual production and application, the variable-tooth gear 100 of the robot finger device of the present scheme can also be replaced by a common missing-tooth gear on the market (in the application scenario where the variable-tooth gear 100 is fixedly arranged to drive the movement of the external member, a missing-tooth gear is not suitable for replacement). Specifically, when a missing-tooth gear (only the partial region of the gear ring side is provided with teeth) is used, the hole on the missing-tooth gear for passing through the third rotating shaft 420 is a non-circular hole (for example, a regular hexagonal hole), and the third rotating shaft 420 is provided with a limiting portion matched with the inner contour shape of the non-circular hole and a cylindrical portion located on both sides of the limiting portion, and the minimum width of the limiting portion is greater than the diameter of the cylindrical portion. When the teeth of the missing-tooth gear are located at the lower part, the missing-tooth gear is equivalent to the lower protruding state of the variable-tooth gear 100. When the missing-tooth gear is pulled along the axial direction of the third rotating shaft 420 to the cylindrical portion region, the missing-tooth gear can freely rotate on the third rotating shaft 420, at this time, the teeth of the missing-tooth gear are not engaged with the first rack structure 520 or the second rack structure 530 of the rack slider 500, which is equivalent to the middle protruding state of the variable-tooth gear 100. When the missing-tooth gear is rotated and the teeth thereof are located at the upper part, the missing-tooth gear is equivalent to the upper protruding state of the variable-tooth gear 100. In other embodiments, the limiting portion can also be arranged on the side surface of the third gear 600, and the missing-tooth gear is slidingly arranged on the cylindrical third rotating shaft 420. When the missing-tooth gear cooperates with the third rotating shaft 420, the missing-tooth gear can rotate relative to the third rotating shaft 420. When the missing-tooth gear is driven to slide to cooperate with the limiting portion on the third gear 600, the missing-tooth gear rotates synchronously with the third gear 600. The working process of the robot finger device in three modes realized by using the missing-tooth gear is the same as that realized by using the variable-tooth gear 100, and details are not repeated here.

[0041] The above scheme involves rotation and translation of the missing-tooth gear, which can be conveniently adjusted by hand, and a prototype can be easily made. The state of the missing-tooth gear can also be adjusted by using a motor, but the missing-tooth gear needs to be additionally translated. The implementation modes include but are not limited to using magnetic materials to make the missing-tooth gear, arranging an electromagnet on one side of the robot finger device, changing the magnetic pole by switching the current direction, realizing attraction or repulsion with the missing-tooth gear, and then translating the missing-tooth gear to the position of free rotation, and then changing the tooth direction of the missing-tooth gear by using a motor and returning the missing-tooth gear to the position required for engagement with the rack slider 500.

[0042] The variable tooth gear 100 and the adaptive three-mode robot finger device of the present application can change the shape and height of the gear teeth 140 by setting the variable tooth gear 100, and the gear teeth 140 can be extended from the through hole 112 or retracted into the through hole 112 under the drive of the rotating structure 120, so that the gear can cooperate with the tooth structure on both sides according to the requirements, and then drive the related mechanism connected with the tooth structure to move, so as to realize the movement of the mechanism in two opposite directions. In this way, one variable tooth gear 100 can realize the switching of the mechanism in different directions and corresponding actions, without the need to set multiple gears and pressure blocks to work together, simplifying the transmission structure of the joint of the robot finger device and reducing the assembly workload of the robot finger device. The adaptive three-mode robot finger device using the above variable tooth gear 100 can realize the switching of the flat clamping underdrive adaptive gripping, the coupling underdrive adaptive gripping and the general underdrive adaptive gripping of the robot finger device by driving the second motor 300 and adjusting the shape and limiting block 800 of the variable tooth gear 100, which expands the gripping range of the robot hand and improves its adaptability. The number of gears involved is reduced, the assembly workload of the robot finger device is reduced, and the use of fewer first elastic members, gears and other transmission parts simplifies the structure and reduces the cost. The aspect ratio is reduced, the appearance is more beautiful and human-like, and the device appearance is more beautiful, which can adapt to more use scenarios without the need to replace, disassemble the gripper and parts, reducing the cost.

[0043] The technical features of the above-mentioned embodiments can be combined in any way. In order to make the description simple, all possible combinations of the technical features in the above-mentioned embodiments are not described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0044] The above-mentioned embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, some modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A variable tooth gear for cooperating with tooth structures on both sides thereof, characterized in that, The variable tooth gear comprises a gear shell, a rotating structure and a gear tooth assembly. The gear shell is internally provided with a cavity. A plurality of through holes are formed in the ring side of the gear shell and are communicated with the cavity. The rotating structure is accommodated in the cavity and can rotate around the center of the cavity. The rotating structure comprises a near-hole part close to the through hole, a far-hole part opposite to the near-hole part and connected with the near-hole part. The gear tooth assembly comprises a plurality of gear teeth which are slid through the through holes one by one and can move towards or away from the rotating center of the rotating structure. Under the action of external force, the rotating structure rotates so that the gear tooth matched with the near-hole part is elongated in the through hole and moves away from the rotating center of the rotating structure, and the gear tooth matched with the far-hole part is retracted in the through hole and moves towards the rotating center of the rotating structure.

2. The variable toothed gear of claim 1, wherein, The rotating structure is a cam. The near-hole part is a convex part of the cam, and the far-hole part is an arc part of the cam. The rotating structure is made of magnetic material, or the surface of the rotating structure is provided with a magnetic layer made of magnetic material. The gear tooth is made of material which can be magnetically attracted, or the surface of the gear tooth close to the rotating structure is provided with an adsorption layer made of material which can be magnetically attracted.

3. The variable toothed gear of claim 1, wherein, The rotating structure is a cam. The near-hole part is a convex part of the cam, and the far-hole part is an arc part of the cam. The variable tooth gear further comprises a plurality of springs which are installed on the gear teeth one by one. One end of the spring is limitedly matched with the part of the gear tooth close to the rotating structure, and the other end of the spring is abutted with the inner side edge of the through hole.

4. The variable toothed gear according to claim 2 or 3, characterized in that One rotating structure is rotatably arranged in the cavity. Or two rotating structures are rotatably arranged in the cavity and are distributed along the axial direction of the gear shell. The two rotating structures are arranged at an included angle.

5. The variable toothed gear of claim 1, wherein, The rotating structure is a cam. The near-hole part is a convex part of the cam, and the far-hole part is an arc part of the cam. One side of the rotating structure is provided with a non-circular ring-shaped sliding groove which is adapted to the contour shape of the rotating structure. One end of the gear tooth close to the rotating structure is fixed with a limiting protrusion which is inserted into the non-circular ring-shaped sliding groove and can slide along the inner wall of the non-circular ring-shaped sliding groove.

6. The variable toothed gear of claim 1, wherein, The rotating structure comprises a disc or a ring which can rotate around the center of the cavity, and a connecting column which is eccentrically fixed on the disc or the ring. The variable tooth gear further comprises a plurality of connecting rods which are sequentially sleeved on the connecting column along the axial direction of the connecting column and are matched with the gear teeth one by one. One end of the connecting rod is rotatably matched with the connecting column, and the other end of the connecting rod is rotatably matched with the gear tooth.

7. The variable toothed gear of claim 1, wherein, A first motor is arranged in the cavity and is used to drive the rotating structure to rotate. Or an arc-shaped guide hole is formed in the gear shell and is communicated with the cavity and penetrates through the outer surface of the gear shell. A gripping part is fixed on the rotating structure and protrudes from the arc-shaped guide hole.

8. An adaptive three-mode robotic finger device, comprising: The gear shifting mechanism is a step of shifting the gears to the first and second gears, and the step of shifting the gears to the first and second gears is a step of shifting the gears to the first and second gears, the step of shifting the gears to the first and second gears being a step of shifting the gears to the first and second gears. The rotating structure rotates under the action of external force, so that the teeth of the variable tooth gear mesh with the first rack structure and push the rack slider to move in the first direction, so that the second finger segment rotates relative to the first finger segment; or the teeth of the variable tooth gear mesh with the second rack structure and push the rack slider to move in the second direction, so that the second finger segment rotates in the opposite direction relative to the first finger segment; or the teeth of the variable tooth gear are separated from the first rack structure and the second rack structure.

9. The adaptive three-mode robotic finger device of claim 8, wherein, The adaptive three-mode robot finger device also includes a transmission structure, a first gear and a second gear located on the outside of the base. The second motor is fixed in the base and extends in the vertical direction. The transmission structure includes a worm gear located above the second motor and driven by the motor shaft of the second motor, and a turbine located above the worm gear and meshed with the worm gear. The turbine is arranged vertically to the worm gear. The turbine is connected to the first gear through a first rotating shaft passing through the base, and the turbine rotates coaxially with the first gear. The second gear is meshed with the first gear, and the second gear is connected to the first finger segment through the second rotating shaft to drive the first finger segment to rotate.

10. The adaptive three-mode robotic finger device of claim 8, wherein, The limit block is rotatably arranged on the base, and a first elastic member is provided between the limit block and the connecting rod gear. The limit block includes a rotating part rotatably connected to the base, and a limit part fixed to the end of the rotating part. The width of the limit part is greater than the width of the rotating part, and a first limit step is formed on the side of the limit part adjacent to the rotating part, and a second limit step is formed on the other side of the limit part adjacent to the rotating part; or the limit block is a pin slidably inserted into the side of the base; A limiting piece is fixed in the first finger segment, and a guide through hole is provided on the rack slider between the first rack structure and the third rack structure. The limiting piece passes through the guide through hole and slidably cooperates with the rack slider; a guide limiting hole is provided on the top of the first finger segment for the second finger segment to pass through and limit the rotation range of the second finger segment.

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