JP4246052B2 - Robot joint structure - Google Patents

Description

  The present invention relates to a joint structure applied to an arm joint or a finger joint of a robot, and more specifically, to load a reaction force acting on the joint with a small and simple structure when an object or the like is gripped. Regarding improvements.

JP-A-5-92377 Japanese Patent Laid-Open No. 10-217158 JP 2002-113681 A

  Conventionally, as a joint structure of this type of robot, as disclosed in Japanese Patent Laid-Open No. 5-92377, a rotating shaft of a motor for driving an arm is provided in parallel with the central axis of the swinging motion of the arm. It has been known. In this joint structure, the second arm, which is the distal end member, is pivotally supported on the distal end of the first arm, which is the proximal end member, to form a joint portion, while the central axis of the swinging motion in the joint portion A motor is provided on the top, and the rotational movement of the motor is transmitted to the first arm or the second arm via a speed reduction mechanism constituted by a spur gear or the like, and the swinging movement according to the rotational direction and the rotational amount of the motor is performed. Giving between these arms.

  This conventional joint structure is very simple in structure because the rotation axis of the motor is provided in parallel with the central axis of the oscillating motion, but the motor for driving the arm In addition, since the deceleration mechanism protrudes greatly outside the joint portion, the joint portion cannot be configured compactly. For this reason, although it is suitable as a joint structure for a large industrial robot or the like that places importance on robustness and maintenance, it is not suitable for a small joint structure such as a finger structure in a mechanical hand.

  On the other hand, as another joint structure of the robot, as disclosed in Japanese Patent Laid-Open Nos. 10-217158 and 2002-113681, a link mechanism can swing between the first arm and the second arm. In addition, a ball screw is used as a part of the link mechanism, and the first arm is swung with respect to the second arm by rotating the ball screw with a motor. . For example, in the joint structure disclosed in the former Japanese Patent Application Laid-Open No. 10-217158, the second arm on the distal end side is pivotally supported with respect to the first arm on the proximal end side. Is provided with a screw shaft substantially parallel to the arm, and the screw shaft is configured to be rotationally driven by a motor mounted on the second arm. A nut member is screwed onto the screw shaft, and an end portion of a link plate extending from the first arm is rotatably coupled to the nut member. Accordingly, when the motor is rotated, a nut member screwed to the screw shaft moves on the screw shaft in accordance with the rotation direction and the rotation amount of the motor. The nut member includes an end portion of the link plate. Because of this, a pressing force or a pulling force corresponding to the movement of the nut member acts on the second arm from the link plate, thereby causing the second arm to swing with respect to the first arm. It is like that.

In the joint structure disclosed in Japanese Patent Laid-Open No. 10-217158, the link plate is pushed and pulled by the movement of the nut member accompanying the rotation of the screw shaft, thereby causing the second arm to swing relative to the first arm. However, the direction of the pulling force or the pressing force acting on the link plate during the swinging motion does not match the moving direction of the nut member. For this reason, when the second arm swings, a bending moment acts on the screw shaft, and the rigidity of the screw shaft must be increased by increasing the diameter of the screw shaft. There is a problem that a sufficient force cannot be applied to the swing of the two arms.

  In addition, when a robot finger of a mechanical hand that grips an article using this joint structure is configured, the reaction force generated when the article is gripped acts as a bending moment on the screw shaft via the link plate. If the shaft rigidity is not sufficiently secured, the robot finger cannot exhibit a sufficient gripping force. However, increasing the rigidity of the screw shaft with respect to the bending moment leads to an increase in size and weight of the joint structure itself, and there is a problem that a small and lightweight robot finger cannot be configured.

  The present invention has been made in view of such problems, and an object of the present invention is to perform such swinging with a large force when giving swinging motion to the arms connected to each other. In addition, for example, when a robot finger is configured, a large gripping force can be exerted, and a simple structure and a compact robot joint structure are provided.

  In order to achieve the above object, a robot joint structure of the present invention is arranged so as to close a base end side member having a hollow portion, and a hollow portion opening of the base end side member and via a hinge. A distal end member that is swingably connected to the end member, a drive rod that moves forward and backward in the hollow portion of the proximal end member to push and pull the distal end member, and linearly moves the drive rod only in the axial direction A guide member that is freely held and fixed in the hollow portion of the base end side member, and a linear ultrasonic motor that is disposed in the hollow portion of the base end side member and moves the drive rod in the axial direction. Has been.

  In such technical means, if the linear ultrasonic motor is composed of a stator having a piezoelectric element and a slider driven to move in the position direction by the stator, the stator and the slider Any specific structure can be used. In moving the drive rod in the axial direction, the slider of the linear ultrasonic motor may be fixed to the drive rod, or the drive rod itself is used as a slider, and the stator is brought into contact with one surface of the drive rod. You may comprise as follows.

  The guide member that holds the drive rod so as to be linearly movable may be any member that can apply a bending moment acting on the drive rod. However, from the viewpoint of increasing the load capacity against the bending moment while smoothly moving the drive rod in a straight line, the drive rod is formed in a substantially rectangular cross section, and the ball rolls along the axial direction on both side surfaces thereof. A groove is formed, and a guide rolling member is provided with a load rolling groove facing each ball rolling groove of the drive rod, and a large number of balls apply a load between the ball rolling groove and the load rolling groove. However, it is preferable to configure so as to roll.

  According to such a robot joint structure, when a linear ultrasonic motor provided in the hollow portion of the base end side member is driven, the drive rod advances and retreats in the hollow portion and is connected to the base end side member in a swingable manner. The tip end member thus made swings as the drive rod advances and retreats. Since the amount of rocking of the tip side member depends on the amount of advancement / retraction of the drive rod, the tip side member can be moved to an arbitrary amount relative to the base end side member as long as the advance / retreat amount of the drive rod by the linear ultrasonic motor is adjusted. Can be swung only.

At this time, a bending moment acts on the drive rod in addition to the axial pressing force or pulling force, but the guide member fixed in the hollow portion of the proximal end member moves the drive rod in the axial direction. Since only the linear movement is held, the bending moment is loaded by the guide member. Therefore, the drive rod can be smoothly advanced and retracted by the driving force of the linear ultrasonic motor even under the action of a bending moment. The side member can be swung with a large force.

  In addition, when an external force is applied to the tip side member, a bending moment is applied to the drive rod. As described above, the guide member applies the bending moment in the axial direction of the drive rod. Therefore, the external force can be sufficiently loaded. For this reason, for example, when a multi-joint robot finger is configured by repeating the joint structure of the present invention repeatedly, even if the reaction force acts on each joint structure when gripping an article, the reaction force is sufficient. The article can be gripped with a large gripping force.

  Further, the linear ultrasonic motor for moving the drive rod in the axial direction is generally composed of a stator having a piezoelectric element and a slide plate that is given a forward and backward movement in one direction by the stator. Are in contact with each other. For this reason, even when the voltage applied to the piezoelectric element of the stator is turned off, the self-holding force is exhibited, and the slide plate can be held at a fixed position with respect to the stator. Therefore, even if the power supply to the linear ultrasonic motor is cut after the tip end member is swung by a predetermined amount by the drive rod, the drive rod is held at a fixed position without moving, and the tip side member is It can be fixed. That is, if the robot finger is configured using the joint structure of the present invention, the gripping state of the article can be maintained as it is even if the power supply is cut off after the article is gripped, thereby saving energy. it can.

The robot joint structure of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 shows a first embodiment of a robot finger of a mechanical hand to which the present invention is applied. This robot finger 1 has three joints C1, C2, and C3, and each joint is configured to bend freely according to the driving of a linear ultrasonic motor described later. The solid line in the figure shows the state where each joint C1, C2, C3 is bent, and the two-dot chain line shows the state where each joint C1, C2, C3 is extended.

  The robot finger 1 includes a first finger 10 fixed to a main body M of a mechanical hand, a second finger 20 connected to the first finger 10 via a first joint C1, and a second joint C2. It comprises a third finger 30 connected to the second finger 20 and a tip finger 40 connected to the third finger 30 via a third joint C3. Each joint C1, C2, C3 has The structure is applied.

  The first finger 10 and the second finger 20, the second finger 20 and the third finger 30, and the third finger 30 and the tip finger 40 are connected by a hinge 2, respectively. Are connected so as to freely swing with respect to adjacent fingers. The first finger 10, the second finger 20, and the third finger 30 have a hollow portion 11 that passes therethrough, and each of them is formed in a substantially cylindrical shape, and is driven so as to penetrate through the hollow portion 11. A rod 12 is provided. A bellows cover 3 is provided between the fingers to prevent dust from entering.

The first finger 10 will be described as an example. The drive rod 12 is held by a guide member 13 and is movable only in the axial direction (longitudinal direction) in the hollow portion 11, and its tip is attached to the first finger 10. It is connected to the adjacent second finger 20. A long hole 14 is formed at the end of the second finger 20 near the first finger 10 so as to cross the penetration direction of the drive rod 12, and at the tip of the drive rod 12 that penetrates the first finger 10. An upright pin 15 is engaged with the long hole 14. For this reason, when the drive rod 12 is moved in the axial direction, the second finger 20 performs a swinging motion around the hinge 2 with respect to the first finger 10 according to the amount of movement. At this time, the pin 15 erected at the tip of the drive rod 12 slides in the long hole 14 in accordance with the swinging amount of the second finger 20.

  As shown in FIGS. 2 and 3, the hollow portion 11 has a substantially rectangular cross section, and the guide member 13 is screwed to the inner wall of the hollow portion 11. The guide member 13 only needs to hold the drive rod 12 so as to be movable only in the axial direction. As a combination of the drive rod 12 and the guide member 13, for example, a known straight line constituted by a track rail and a slide block is used. A guide device can be used. FIG. 4 shows an example of a known linear guide device. The track rail 50 as the drive rod 12 is formed in a substantially rectangular cross section, and ball rolling grooves 52 in which the balls 51 roll along the longitudinal direction are formed on both side surfaces thereof. On the other hand, the slide block 53 as the guide member 13 has a groove and is formed in a channel shape, and the track rail 50 is loosely fitted in the groove. In addition, a load rolling groove facing the ball rolling groove 52 of the track rail 50 is formed on the inner side surface of the concave groove of the slide block 53, and a large number of balls 51 are ball rolling grooves 52 of the track rail 50. A load acting between the track rail 50 and the slide block 53 is loaded while rolling between the rail and the load rolling groove of the slide block 53. Further, the slide block 53 is formed with an infinite circulation path for the ball 51, and the ball 51 circulates in the infinite circulation path, whereby the track rail 50 moves infinitely in the axial direction with respect to the slide block 53. It is possible. Therefore, by fixing the slide block 53 of such a linear guide device as the guide member 13 to the inner wall of the hollow portion 11 of the first finger 10, the track rail 50 as the drive rod 12 is advanced and retracted in the hollow portion 11. It can be held freely.

  On the other hand, a linear ultrasonic motor 21 is provided in the hollow portion 11 of the first finger 10, and a drive signal is supplied to the linear ultrasonic motor 21 so that the drive rod 12 advances and retracts in the axial direction. It is configured. The linear ultrasonic motor 21 includes a stator 22 having a piezoelectric element and a slide plate with which the stator 22 is pressed. In this embodiment, the stator 22 is in direct pressure contact with the drive rod 12, and the drive rod 12 functions as a slide plate.

  FIG. 5 shows an example of the stator 22. The stator 22 shown in FIG. 5 includes four driving legs 24 made of piezoelectric ceramics on an insulating substrate 23, and the tip ends of these driving legs are in contact with the drive rod 12. Each drive leg 24 is formed by bonding a pair of piezoelectric ceramics 26 a and 26 b via an insulating sheet 25, thereby forming a bimorph, and voltage application timing to the piezoelectric ceramics 26 a and 26 b positioned on both sides of the insulating sheet 25. The drive legs 24 can be freely bent in the bonding direction of the piezoelectric ceramics 26a and 26b by shifting the position. As this stator 22, for example, Piezo Legs (trade name) manufactured by Piezo Motor Co., Ltd. can be used.

FIG. 6 illustrates a state in which the drive leg 24 conveys the drive rod 12. The piezoelectric ceramics 26a and 26b expand when a voltage is applied, but as shown in FIG. 6A, a voltage is applied to one piezoelectric ceramic 26a of the pair of piezoelectric ceramics 26a and 26b constituting the drive leg 24. Is applied, the drive leg 24 bends in the opposite direction to the piezoelectric ceramic 26a to which a voltage is applied, and the tip thereof contacts the drive rod 12. Next, when a voltage is applied to both the piezoelectric ceramics 26a and 26b, as shown in FIG. 6B, the drive leg 24 is restored from the bent state while being extended, and the drive leg 24 causes the drive rod 12 to move. Transport. When the voltage application to the piezoelectric ceramic 26a to which the voltage is first applied is stopped, as shown in FIG. 6C, the drive leg 24 bends in the direction opposite to the state shown in the partial diagram (a). Thus, the drive rod 12 is further conveyed. When the voltage application to both the piezoelectric ceramics 26a and 26b is stopped, as shown in FIG. 6 (d), the driving leg 24 is canceled to its original shape while being contracted to the original shape. The tip is separated from the drive rod 12. Therefore, the drive rod 12 can be conveyed in one direction by repeating the partial drawings (a) to (d). In addition, the drive rod 12 can be transported in the reverse direction by changing the order in which the voltages are applied to the pair of piezoelectric ceramics 26a and 26b constituting the drive leg 24. Further, when the drive rod 12 is transported by one drive leg 24, the drive rod 12 is intermittently transported. The stator 22 of this embodiment is provided with four drive legs 24. Therefore, by shifting the phase of voltage application to these drive legs 24, the drive rod 12 can be continuously moved in one direction without interruption.

  As shown in FIG. 3, a concave groove 31 for holding the stator 22 is provided in the hollow portion 11 of the first finger 10 in parallel with the moving direction of the drive rod 12. It is held inside and faces the drive rod. Further, in order to prevent the drive leg 24 of the stator 22 from sliding relative to the drive rod 12, the stator 22 disposed in the concave groove 31 is pressed toward the drive rod 12 on the outside of the first finger 10. A preload spring 32 is provided. The preload spring 32 includes a pair of leg portions 32 a and 32 a and is formed in a channel shape. The leg portions 32 a pass through the first finger 10 and come into contact with the insulating substrate 23 of the stator 22 in the concave groove 31. It is like that. The preload spring 32 is screwed to the first finger 10 by an adjusting screw 33. By changing the fastening amount of the adjusting screw 33, the preload spring 32 directs the stator 22 toward the drive rod 12. The energizing force can be adjusted.

  That is, in the hollow portion 11 of the first finger 10 in this embodiment, the guide member 13 holding the drive rod 12 and the stator 22 of the linear ultrasonic motor 21 are arranged so as to face each other, and the stator By urging 22 toward the guide member 13, the drive leg 24 of the stator 22 comes into pressure contact with the drive rod 12 held movably by the guide member 13. The stator 22 is fixed so as not to move in the concave groove 31 after being disposed in the concave groove 31 of the first finger 10.

  In such a structure of the first joint C1, when a drive signal is applied to the stator 22 of the linear ultrasonic motor 21 accommodated in the hollow portion 11 of the first finger 10, the drive leg 24 of the stator 22 is shown in FIG. As shown in FIG. 5, the drive rod 12 is conveyed, and the drive rod 12 moves in the axial direction while being supported by the guide member 13. When the drive rod 12 protrudes from the hollow portion 11 of the first finger 10, the second finger 20 is pressed according to the protruding amount, and the second finger 20 rotates around the hinge 2. As a result, a state in which the second finger 20 is bent with respect to the first finger 10 is created. When the drive rod 12 is retracted into the hollow portion 11 of the first finger 10, the second finger 20 rotates so as to be pulled back toward the first finger 10, and the second finger 20 is connected to the first finger 10. Line up on a straight line.

The hinge 2 that rotatably connects the second finger 20 with the first finger 10 is located at the opening edge of the hollow portion 11 of the first finger 10 and at the edge of the concave groove 31 in which the stator 22 is held. The slide rod 12 is located on the opposite side of the guide member 13 with the hollow portion 11 in between. For this reason, the distance from the position where the pin 15 provided at the tip of the slide rod 12 is engaged with the elongated hole 14 of the second finger 20 to the hinge 2 can be set larger, and the slide is correspondingly increased. When the rod 12 is advanced and retracted, a large rotational torque can be applied to the second finger 20.

  The same structure as that of the first finger 10 is applied to the second finger 20 and the third finger 30. That is, the guide member 13 is fixed to the inner wall surface of the hollow portion 11, and the stator 22 of the linear ultrasonic motor 21 is disposed at a position facing the guide member 13 across the hollow portion 11. Thus, the drive rod 12 held movably in the axial direction can be arbitrarily advanced and retracted by the stator 22. Thus, the third finger 30 can be freely bent or extended with respect to the second finger 20, and the tip finger 40 can be freely bent or extended with respect to the third finger 30. It should be noted that parts attached to the fingers 20 and 30 are denoted by the same reference numerals as those attached to the first finger 10 in FIG. 1, and detailed description thereof is omitted here.

  As described above, according to the robot finger 1 of the present embodiment in which the first finger 10, the second finger 20, the third finger 30 and the tip finger 40 are connected by the hinge 2, the linear ultrasonic wave incorporated in each finger. By advancing and retracting the drive rod 12 by the motor 21, the first joint C1, the second joint C2, and the third joint C3 can be freely bent, and by operating a plurality of such robot fingers 1 simultaneously, Work such as gripping the object can be performed.

  In using such a robot finger 1, linear ultrasonic motors 21 built in the first finger 10, the second finger 20, and the third finger 30 are separately driven independently, so that each joint C1, C2, C3 Can be bent or extended individually, and objects of various shapes can be accurately grasped.

  Further, when the object is gripped, the reaction force acts on the joints C1, C2, and C3, and the reaction force acts as a bending moment on the drive rod 12, but the drive rod 12 is linearly guided. If the slider 53 assembled | attached to the said track rail 50 via many balls 51 is used as the guide member 13 which supports the movement of the track rod 50 of this apparatus to the axial direction of this drive rod 12, it will act on the drive rod 12 The drive rod 12 can be smoothly guided in the axial direction while applying a bending moment to bend, and the joints C1, C2, C3 can bend or extend while reliably applying a reaction force of the gripping force. It becomes possible.

  Further, in the linear ultrasonic motor 21, since the drive leg 24 of the stator 22 is always in pressure contact with the drive rod 12, the drive rod 12 advances and retreats when voltage application to each drive leg 24 of the stator 22 is interrupted. Therefore, once the joints C1, C2, and C3 are bent or extended, the voltage application to the stator 22 is stopped to maintain the bent or extended state. Is possible. Therefore, it is possible to manufacture the robot finger 1 which is extremely energy saving as compared with the case where the robot finger is configured using a DC motor.

  FIG. 7 shows a second embodiment of the robot finger to which the present invention is applied. This robot finger 100 also has three joints C1, C2, and C3 as in the first embodiment, and each joint is configured to bend freely according to the drive of the linear ultrasonic motor. A partial diagram (a) shows a state in which each joint is extended, a partial diagram (b) shows a state in which only the first joint C1 is bent, and a partial diagram (c) shows a state in which the joints C2 and C3 are bent. .

  The robot finger 100 includes a first finger 60 fixed to the body of the mechanical hand, a second finger 70 connected to the first finger 60 via a first joint C1, and a second finger C2 via a second joint C2. The third finger 80 is connected to the second finger 70, and the distal finger 90 is connected to the third finger 80 via the third joint C3. Each joint C1, C2, C3 has the structure of the present invention. Has been applied.

  Between the first finger 60 and the second finger 70, between the second finger 70 and the third finger 80, and between the third finger 80 and the tip finger 90, the hinge 2a, 2b and 2c are connected to each other so that each finger can swing freely with respect to adjacent fingers. Moreover, the 1st finger 60, the 2nd finger 70, and the 3rd finger 80 have a hollow part which penetrates this, and each is formed in the substantially cylindrical shape.

  However, the hinge 2a for connecting the first finger 60 and the second finger 70 and the hinge 2c for connecting the third finger 80 and the tip finger 90 are located on the bending side of the robot finger 100, but the second finger is not provided. The hinge 2b connecting the 70 and the third finger 80 is provided on the development side of the robot finger 100, that is, on the side opposite to the hinges 2a and 2c.

  On the other hand, in the first embodiment, a drive rod 12 is provided for each of the first finger 10, the second finger 20, and the third finger 30, and one end of the drive rod 12 in each finger is the end of the adjacent finger. In this second embodiment, the drive rods 61 and 62 are provided only in the hollow portions of the first finger 60 and the third finger 80. Further, only one end of the drive rod 61 in the first finger 60 is connected to the second finger 70, but one end of the drive rod 62 in the third finger 80 is connected to the second finger 70 and the other end is connected to the second finger 70. The tip finger 90 is configured to be connected. As a result, no drive rod is provided in the second finger 70.

  The drive rods 61 and 62 provided in the hollow portions of the first finger 60 and the third finger 80 are supported so as to be movable only in the axial direction by the same guide member 13 as in the first embodiment. It can be arbitrarily moved in the axial direction by the same linear ultrasonic motor 21 as in the first embodiment. Further, the connecting structure of the end portions of the drive rods 61 and 62 and the second finger 70 and the tip finger 90 is the same as that of the first embodiment. Therefore, the same structure as that of the first embodiment is denoted by the same reference numeral in FIG. 7, and the detailed description thereof is omitted.

  In using the robot finger 100 of the second embodiment, when the linear ultrasonic motor 21 built in the first finger 60 is driven and the drive rod 61 is advanced and retracted, as shown in FIG. In addition, the joint C1 bends or extends independently. On the other hand, when the linear ultrasonic motor 21 built in the third finger 80 is driven and the drive rod 62 is advanced toward the tip finger 90, the tip finger 90 is moved to the first finger 90 as shown in FIG. The joint C3 is bent in a direction away from the third finger 80 and the joint C3 is bent. At the same time, the drive rod 62 attracts the second finger 70 to the third finger 80, so that the third finger 80 is against the second finger 70. Will bend. When the drive rod 62 is pulled back into the third finger 80 from the state of FIG. 7C, the joint C3 extends, and at the same time, the drive rod 62 separates the second finger 70 from the third finger 80. Therefore, the joint C2 can be extended. That is, when the linear ultrasonic motor 21 in the third finger 80 is driven, the joint C2 and the joint C3 can be bent or extended simultaneously.

  As a result, according to the robot finger 100 of the second embodiment, the joint C2 that connects the second finger 70 and the third finger 80 can be provided even though the driving means is not provided in the second finger 70. It can be bent or extended, the weight of the entire robot finger 100 can be reduced, and the bending moment acting on the drive rod 61 in the first finger 60 can be reduced.

  In the above embodiment, an example in which the joint structure of the present invention is applied to a robot finger of a mechanical hand has been described. However, the present invention is not limited to this, for example, a joint of a robot arm for feeding a mechanical hand to a predetermined position. It can also be applied to structures.

It is sectional drawing which shows 1st Example of the robot finger to which this invention is applied. It is sectional drawing of the 1st finger which concerns on 1st Example. It is a perspective view which shows the 1st finger which concerns on 1st Example. It is a perspective view which shows an example of the linear guide apparatus which can be used as a drive rod and a guide member concerning 1st Example. It is a perspective view which shows the stator of the linear ultrasonic motor which concerns on 1st Example. It is explanatory drawing which shows the cycle of a motion of the drive leg of the stator which concerns on 1st Example. It is sectional drawing which shows 2nd Example of the robot finger to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Robot finger, 2 ... Hinge, 10 ... 1st finger, 11 ... Hollow part, 12 ... Drive rod, 13 ... Guide member, 20 ... 2nd finger, 21 ... Linear ultrasonic motor, 22 ... Stator, 30 ... 1st 3 fingers, 40 ... tip fingers

Claims (6)

A proximal end member having a hollow portion, a distal end side member disposed so as to close the hollow portion opening of the proximal end side member, and pivotably connected to the proximal end member via a hinge; A drive rod that moves forward and backward in the hollow portion of the base end side member and pushes and pulls the tip end side member, and holds the drive rod so as to be linearly movable only in the axial direction and is fixed in the hollow portion of the base end side member. And a linear ultrasonic motor that is disposed in the hollow portion of the base end side member and moves the drive rod in the axial direction,
The drive rod is formed in a substantially rectangular cross section, and one surface of the drive rod is formed as a contact surface of the stator of the linear ultrasonic motor, and a ball rolling groove along the axial direction on both side surfaces sandwiching the contact surface The guide member is provided with a load rolling groove facing each ball rolling groove of the drive rod, and a large number of balls are loaded between the ball rolling groove and the load rolling groove. Rolling while loading
The guide member and the linear ultrasonic motor are disposed so as to face each other through the drive rod in the hollow portion of the base end side member, and the stator of the linear ultrasonic motor is attached toward the contact surface with the drive rod. Robot joint structure characterized by being energized . The stator of the linear ultrasonic motor includes a plurality of drive legs formed by bonding a pair of piezoelectric actuators along the axial direction of the drive rod, and the tip of each drive leg is repeatedly brought into contact with the drive rod. The robot joint structure according to Item 1. 2. The robot joint structure according to claim 1, further comprising biasing force adjusting means for pressing the stator of the ultrasonic motor toward the drive rod . The hinge connecting the base end side member and the tip end side member is provided at a position facing an opening edge of the hollow portion of the base end side member and the guide member across the hollow portion. The robot joint structure according to claim 1. The robot joint structure according to claim 1 is repeatedly provided by providing a hollow portion in the distal end side member similarly to the proximal end side member, and disposing the drive rod, guide member, and linear ultrasonic motor in the hollow portion. Robot finger structure characterized by that. A proximal end side member having a hollow portion and a pair of distal end side members disposed so as to close the opening of the hollow portion of the proximal end side member and swingably connected to the proximal end member via a hinge And a rear end side member, a drive rod which advances and retreats in the hollow portion of the base end side member, and both ends are respectively connected to the front end side member and the rear end side member, and the drive rod is linearly movable only in the axial direction. And a guide member fixed in the hollow portion of the base end side member, and a linear ultrasonic motor disposed in the hollow portion of the base end side member and moving the drive rod in the axial direction. ,
The drive rod is formed in a substantially rectangular cross section, and one surface of the drive rod is formed as a contact surface of the stator of the linear ultrasonic motor, and a ball rolling groove along the axial direction on both side surfaces sandwiching the contact surface The guide member is provided with a load rolling groove facing each ball rolling groove of the drive rod, and a large number of balls are loaded between the ball rolling groove and the load rolling groove. Rolling while loading
The guide member and the linear ultrasonic motor are disposed so as to face each other through the drive rod in the hollow portion of the base end side member, and the stator of the linear ultrasonic motor is attached toward the contact surface with the drive rod. Robot joint structure characterized by being energized .

Images