JP6309889B2 - Electric gripper device - Google Patents

Description

  The present invention relates to an electric gripper device, and in particular, an electric gripper driven by a motor for gripping a workpiece and performing positioning, length measurement, and the like in automatic assembly of products, parts transportation, inspection, etc. in an FA (Factory Automation) assembly process. Relates to the device.

  2. Description of the Related Art Conventionally, an electric gripper device includes a cam member that rotates forward and backward by a motor and a pair of gripping members that slide linearly along a rail, and the cam followers (drive pins) of the pair of gripping members are cam members. A pair of cam grooves that are slidably fitted to the cam member are formed in a spiral shape on the cam member, and a pair of gripping members slide toward and away from each other along the rail by forward and reverse rotation of the cam member by a motor is proposed. (For example, refer to Patent Document 1).

  The cam groove of the cam member in this type of electric gripper device is formed in a spiral shape along the Archimedes spiral so that the thrust of the gripping member generated by the rotational torque of the motor is constant at any position.

JP 2009-226506 A

  However, in the electric gripper device of Patent Document 1, the stroke range of the gripping member when the rotational motion of the cam member by the motor is converted into the linear motion in the cam follower (drive pin) of the gripping member is limited to the radius of the cam member. Therefore, in order to shorten the length of the stroke range, the radius of the cam member has to be increased. In this case, there is a problem that the entire apparatus is enlarged.

  In addition, the electric gripper device of Patent Document 1 requires a linear guide for linearly sliding the cam member, cam follower, and gripping member. The linear guide has high accuracy in both the finite track method and the endless track method. There is a problem that a complicated grinding process is required and the configuration is complicated.

  Furthermore, when the gripping member is used in a clean environment such as a clean room, it is common to attach a cover to the linear guide as a measure against grease scattering, or to cover the linear guide with a bellows-shaped cover. As a result, there is a problem that the size is further increased.

  The present invention has been made to solve such a problem, and is an electric motor capable of linearly moving a gripping member without using a linear guide and extending its stroke range while having a small size and a simple configuration. A gripper device is to be proposed.

  In order to solve this problem, in the present invention, a main body (3) including a motor (2) and a gear mechanism (11, 12, 13) for transmitting the rotation of the motor shaft (2a) of the motor (2). ) And the gear mechanism (11, 12, 13), and the main body (3) is sandwiched between the outer sides of the main body (3) so that the rotation directions are opposite to each other. The two first arm portions (21, 31) arranged opposite to each other, and the distal end portions (21b, 31b) of the two first arm portions (21, 31), the base end portions (22a, 32a) Two second arm portions (22, 32) on which the two arm portions (22, 32) are supported and tip pins (22b, 32b) of the two second arm portions (22, 32) are connected to each other in a freely rotatable manner. (37), a first grip portion (40) fixed to the connecting pin (37), and the first handle Fixed at a position facing the first gripping part (40) on the main body part (3) separated from the part (40) by a predetermined distance, and grips the workpiece with the first gripping part (40) And a second grip part (50).

  In the present invention, following the second arm portion (32) while maintaining a state parallel to one of the two second arm portions (22, 32). An auxiliary arm portion (34) that operates is further provided, and the auxiliary arm portion (34) is supported by the first grip portion (40).

  Further, in the present invention, the two base end portions (32a, 34a) are rotatably supported while maintaining the parallel state of the one second arm portion (32) and the auxiliary arm portion (34). The moving part of the first gripping part (40) and a supporting arm part (35) provided so as to be movable in a direction orthogonal to the moving direction are further provided.

  Further, in the present invention, the gear mechanism is orthogonal to a motor gear (11) having a bevel gear structure fixed to a tip of a motor shaft (2a) of the motor (2) and a rotation center axis of the motor gear (11). A bevel gear structure having a rotation center axis and meshed with the motor gear (11) in a state of being opposed to each other and rotated in the opposite direction according to the rotation of the motor gear (11). A first gear (12) and a second gear (13) are provided, and the two first arm portions (21, 31) are fixed to the first gear (12) and the second gear (13). It is characterized by that.

  According to the present invention, when the rotation of the motor shaft (2a) of the motor (2) is transmitted to the two first arm portions (21, 31) via the gear mechanism (11, 12, 13), the two Since the first arm portions (21, 31) rotate with their rotation directions being opposite to each other, the two first arm portions (21, 31) are supported by the tip portions (21b, 31b) of the two first arm portions (21, 31). The first gripping part (40) fixed to the connecting pin (37) that connects the tip parts (22b, 32b) of the two arm parts (22, 32) to each other is in relation to the second gripping part (50). Move linearly so as to approach or separate. As a result, the workpiece (wk) can be gripped or released by the first gripping portion 40 and the second gripping portion (50), and thus the first without using a linear guide while having a small size and a simple configuration. The grip part (40) can be moved linearly. Moreover, the stroke range at the time of gripping or releasing the workpiece (wk) can be further increased by simply setting the first arm (21, 31) and the second arm (22, 32) longer.

  According to the present invention, the second arm portion (32) is followed while maintaining a state parallel to one of the two second arm portions (22, 32). Since the auxiliary arm part (34) that moves is supported by the first grip part (40), the auxiliary arm part (34) maintains the orientation of the first grip part (40) relative to the second grip part (50). The first gripping part (40) can be moved linearly while being kept.

  According to the present invention, while maintaining the parallel state of the one second arm portion (32) and the auxiliary arm portion (34), the two base end portions (32a, 34a) are rotatably supported, Since the support arm portion (35) is provided so as to be movable in a direction orthogonal to the moving direction of the first gripping portion (40) and the moving direction thereof, the first gripping portion (40) is moved in the moving direction. As a result, the first gripping part (40) can be linearly moved in a stable state while maintaining the orientation with respect to the second gripping part (50) by the support arm part (35).

  According to the present invention, the motor gear (11) having a bevel gear structure fixed to the tip of the motor shaft (2a) of the motor (2), and the rotation center axis orthogonal to the rotation center axis of the motor gear (11), A first gear (12) having a bevel gear structure, which is engaged with the motor gear (11) in a state of being opposed to each other, and rotated in the opposite direction according to the rotation of the motor gear (11), and Since the two first arm portions (21, 31) are fixed to the second gear (13), the number of parts of the gear mechanism (11, 12, 13) is reduced to simplify the configuration and It is possible to reduce the size.

It is an external view which shows the whole external appearance structure (1) of the electric gripper apparatus in this Embodiment. It is an external view which shows the whole external appearance structure (2) of the electric gripper apparatus in this Embodiment. It is an external view which shows the whole external appearance structure (1) which the gear structure of the electric gripper apparatus in this Embodiment exposed. It is an external view which shows the whole external appearance structure (2) which the gear structure of the electric gripper apparatus in this Embodiment exposed. It is a side view which shows the whole external appearance structure (3) which the gear structure of the electric gripper apparatus in this Embodiment exposed. It is a perspective view which shows the whole external appearance structure (4) which the gear structure of the electric gripper apparatus in this Embodiment exposed. It is a side view which shows the whole external appearance structure which the gear structure of the electric gripper apparatus in this Embodiment is not exposed. It is an external view which shows the whole external appearance structure (1) which shows the workpiece | work holding state of the electric gripper apparatus in this Embodiment. It is an external view which shows the whole external appearance structure (2) which shows the workpiece | work holding state of the electric gripper apparatus in this Embodiment. It is a figure which shows the motion model of a movable side holding part. It is the figure which represented the movement model of the movable side holding part as crank movement.

  Next, an embodiment of the present invention will be described with reference to the drawings.

<Configuration of electric gripper device>
As shown in FIGS. 1 to 9, the link type electric gripper device 1 according to the present embodiment is fixed to, for example, a stepping motor (hereinafter simply referred to as “motor”) 2 and one end of the motor 2. The main body part 3 and the grip part 4 connected to the main body part 3 are configured. The grip part 4 has a function of gripping the workpiece wk or releasing the workpiece wk.

  1 and 2 show a state in which the inside of the main body 3 is concealed, while FIGS. 3 to 9 show the outer side surface so that the inside of the main body 3 can be seen. The state where a part of and the top surface are removed is shown.

  However, FIG. 3 to FIG. 9 are merely expressed so that the inside of the main body 3 can be seen for the sake of explanation, and actually the inside of the main body 3 cannot be seen from the outside. is there.

  The main body 3 has a top surface 3 u (FIG. 1) and a bottom surface 3 z (FIG. 6), has a rectangular tube shape in which an internal space is formed, and penetrates the bottom surface 3 z on the side connected to the motor 2. The motor shaft base 2b of the motor 2 is fitted and fixed in the hole.

  Further, on the outer side surface 3a (FIG. 1) of the main body 3, a fixed-side gripping portion 50 as a second gripping portion having a substantially L shape in side view with which one end of the work wk comes into contact protrudes from the outer side surface 3a. In this state, it is fixed integrally.

  The fixed-side grip 50 is formed by integrating a base 50k that protrudes linearly from the outer side surface 3a of the main body 3 and a workpiece contact 50h that is bent 90 degrees on the tip side of the base 50k. Yes.

  The fixed-side gripping portion 50 is formed on the outer side surface of the main body 3 so that the base portion 50k and the workpiece contact portion 50h face the base portion 40k and the workpiece contact portion 40h of the movable gripping portion 40 as a first gripping portion to be described later. 3a is provided.

  Furthermore, a stay 6 protruding from the outer side surface 3b is integrally fixed to the outer side surface 3b adjacent to the outer side surface 3a of the main body 3 in a direction orthogonal to the fixed-side grip portion 50.

  A motor gear 11 formed of a bevel gear is integrally fixed to the tip of the motor shaft 2 a (FIG. 3) of the motor 2. The motor gear 11 is meshed with the motor gear 11 in a state where a first gear 12 and a second gear 13, which are bevel gears, each having a rotation center axis orthogonal to the rotation center axis of the motor gear 11 are arranged to face each other. Yes. The first gear 12 and the second gear 13 have the same structure.

  The first gear 12 and the second gear 13 are simultaneously driven and rotated in accordance with the rotation of the motor gear 11. At this time, the first gear 12 and the second gear 13 are disposed opposite to each other with respect to the motor gear 11. When the outer side surface 3a is viewed from the front, the rotation direction of the first gear 12 and the rotation direction of the second gear 13 are opposite to each other.

  The motor gear 11, the first gear 12 and the second gear 13 constitute a gear mechanism. This gear mechanism is built in the main body 3 and is hidden so that it cannot be seen from the outside.

  The first gear 12 has a cylindrical base 12a rotatably supported on an outer side surface 3a (not shown in FIG. 3) of the main body 3 via a bearing 12b. The second gear 13 has a cylindrical base portion 13a that is rotatably supported on the outer side surface 3c of the main body 3 via a bearing 13b.

  The base 12a of the first gear 12 (FIG. 5) is formed with a bottomed fitting hole (not shown) along the rotation center axis of the first gear 12 with respect to the center of the end face of the tip portion. . Similarly to the base 12a of the first gear 12, the base 13a of the second gear 13 has a bottomed fitting hole (not shown) along the rotation center axis of the second gear 13 with respect to the center of the end surface of the tip portion. ) Is formed.

  A pin provided on the base end portion 21a of the work side first arm portion 21 as the first arm portion is fitted and fixed to the bottomed fitting hole portion of the base portion 12a of the first gear 12. Accordingly, the work-side first arm portion 21 rotates around the pin of the base end portion 21a integrally with the rotation of the first gear 12.

  The work-side first arm portion 21 is a prismatic member having a predetermined length, and as described above, the base end portion 21a projects toward the bottomed fitting hole portion of the base portion 12a of the first gear 12. A pin (not shown) is provided, and a pin 21 bp that protrudes in the same direction as the pin is provided at the tip portion 21 b.

  The pin 21bp of the work side first arm portion 21 is opposed to the through hole of the base end portion 22a of the work side second arm portion 22 as a second arm portion having an arm length longer than the work side first arm portion 21. The bearing is supported by a bearing.

  As described above, the work side second arm portion 22 has a through hole formed in the base end portion 22a and a bearing attached to the through hole, and a through hole is also formed in the tip end portion 22b. A bearing is attached to the through hole.

  A pin provided on the base end portion 31a of the non-work side first arm portion 31 is fitted and fixed to the bottomed fitting hole portion of the base portion 13a of the second gear 13 (FIG. 5). Therefore, the non-work side first arm portion 31 rotates around the pin of the base end portion 31a integrally with the rotation of the second gear 13.

  The non-work side first arm portion 31 is a prismatic member having the same length as the work side first arm portion 21, and as described above, the base end portion 31 a has the base portion 13 a of the second gear 13. A pin (not shown) protruding toward the bottom fitting hole is provided, and a pin 31bp protruding in the same direction as the pin is provided at the tip 31b.

  The pin 31bp of the non-work side first arm portion 31 is supported by a bearing with respect to the through hole of the base end portion 32a of the non-work side second arm portion 32 having an arm length longer than that of the non-work side first arm portion 31. It is supported rotatably.

  As described above, the non-work side second arm portion 32 has a through hole formed in the base end portion 32a and a bearing attached to the through hole, and a through hole is also formed in the distal end portion 32b. A bearing is attached to the through hole.

  As described above, the work-side first arm portion 21 and the non-work-side first arm portion 31 are outside the main body portion 3 and are disposed to face each other with the main body portion 3 interposed therebetween. The rotation in the CW (clock Wise) direction or CCW (counter clock wise) direction causes the first and second gears 12 and 13 to rotate in opposite directions.

  For the through hole formed in the tip end portion 22b of the work side second arm portion 22 and the through hole formed in the tip end portion 32b of the non-work side second arm portion 32, the work side second arm portion 22 is provided. A connecting pin 37 that connects the front end portion 22b and the front end portion 32b of the non-work side second arm portion 32 to each other is rotatably supported via a bearing.

  As shown in FIGS. 8 and 9, the workpiece side first arm portion 21, the workpiece side second arm portion 22, the non-work side first arm portion 31, the non-work side second arm portion 32, and the connecting pin 37. A substantially rhombus-shaped rhombus link mechanism is configured.

  Here, as shown in FIG. 5, the connecting pin 37 is supported in a state in which the through hole of the tip end portion 22 b of the work-side second arm portion 22 protrudes, and the protruding portion is the movable side as the first gripping portion. The base 40k of the grip 40 is rotatably supported. In this case, the connecting pin 37 is rotatably supported via a bearing in a concave hole 40a (FIGS. 6 and 7) on one end side of the base portion 40k of the movable gripping portion 40.

  The movable side gripping portion 40 includes a base 40k having a predetermined length, and a workpiece contact portion 40h having a substantially L shape in side view protruding from one end side of the base 40k toward the fixed side gripping portion 50. The abutting portion 40h is disposed so as to face the workpiece abutting portion 50h of the fixed gripping portion 50 described above.

  Therefore, when the movable gripping portion 40 moves linearly along the direction of arrow A, between the workpiece contact portion 40h of the movable gripping portion 40 and the workpiece contact portion 50h of the fixed gripping portion 50, One end and the other end of the work wk are brought into contact with each other to be gripped.

  The stay 6 has a straight portion extending linearly toward the tip thereof, and an S-shaped curved portion formed at the tip of the straight portion, and the tip portion 6a of the curved portion has a non-work side. A through hole for supporting the base end portion 33 a of the non-work side first auxiliary arm portion 33 having the same length as the first arm portion 31 is provided.

  Here, as shown in FIG. 9, the straight portion of the stay 6 is set to such a length that the distal end portion 31 b of the non-work side first arm portion 31 does not interfere with the distal end portion 6 a of the stay 6. . Note that the distal end portion 6 a of the stay 6 is shifted via a curved portion in a direction away from the outer side surface 3 c of the main body portion 3 as compared with the straight portion of the stay 6.

  A bearing is attached to the through hole of the distal end portion 6a of the stay 6, and a pin 33ap provided at the base end portion 33a of the non-work side first auxiliary arm portion 33 is rotated with respect to the through hole. It is supported freely.

  As described above, the non-work side first auxiliary arm portion 33 is provided with the pin 33ap at the base end portion 33a, and the distal end portion 33b is opposite to the pin 33ap. A pin 33 bp protruding in the same direction as the 31 pin 31 bp is provided.

  The pin 33 bp of the tip 33 b of the non-work side first auxiliary arm 33 has the same length as the stay 6 and is a through hole formed in one end 35 a of the support arm 35 arranged in parallel with the stay 6. It is supported rotatably via a bearing.

  As described above, the support arm portion 35 has a through hole formed in the one end portion 35a and a bearing attached to the through hole, and a through hole is also formed in the other end portion 35b. Bearings are installed.

  The other end portion 35b of the support arm portion 35 is disposed between the distal end portion 31b of the non-work side first arm portion 31 and the base end portion 32a of the non-work side first arm portion 32 (FIGS. 3 to 5). The pin 31bp of the distal end portion 31b of the non-work side first arm portion 31 is provided in each of the through holes of the other end portion 35b of the support arm portion 35 and the base end portion 32a of the non-work side first arm portion 32. It is supported so that it can rotate freely.

  A pin 35cp (FIG. 5) protruding in the same direction as the pin 31bp of the non-work side first arm portion 31 and the pin 33bp of the non-work side first auxiliary arm portion 33 is integrally formed at the substantially central portion of the support arm portion 35. Is provided.

  The pin 35 cp of the support arm 35 is rotatably supported by a bearing with respect to the through hole of the base end 34 a of the non-work side second auxiliary arm 34 having the same arm length as the non-work side second arm 32. Has been.

  As described above, the non-work side second auxiliary arm portion 34 has a through hole formed in the base end portion 34a and a bearing attached to the through hole, and a through hole is also formed in the distal end portion 34b. In addition, a bearing is attached to the through hole.

  A connecting pin 37 is provided in the through hole of the tip end portion 34b of the non-work side second auxiliary arm portion 34 and the concave hole 40b (FIGS. 6 and 7) provided on the other end side of the base portion 40k of the movable gripping portion 40. The connecting pin 38 having the same length as that is rotatably supported.

  The distance between the concave hole 40a of the base 40k and the concave hole 40b and the distance between the pin 35cp of the support arm 35 and the through hole of the base end 35a are set to the same length.

  For this reason, the tip end portion 32b of the non-work side second arm portion 32 and the tip end portion 34b of the non-work side second auxiliary arm portion 34 are connected to the concave holes 40a of the base portion 40k of the movable side grip portion 40 via the connecting pins 37 and 38. When supported by the concave hole 40b, the parallel state of the non-work side second arm portion 32 and the non-work side second auxiliary arm portion 34 is maintained.

  As a result, as shown in FIG. 8, the non-work side second arm part 32, the support arm part 35, the non-work side second auxiliary arm part 34, and the base 40k of the movable side grip part 40 make the movable side grip part 40 A parallelogram link mechanism having a parallelogram shape for maintaining the orientation of the workpiece contact portion 40h relative to the workpiece contact portion 50h when moved in the arrow AB direction is configured.

  In this parallelogram link mechanism, the work contact portion 40 h of the movable gripping portion 40 supported via the non-work side second arm portion 32 and the connecting pin 37 is formed by the rotation of the non-work side first arm portion 31. Work gripping guarantee function for maintaining the orientation of the workpiece contact portion 40h relative to the workpiece contact portion 50h by the non-workside second auxiliary arm portion 34 and the support arm portion 35 when moving in the direction of arrow A to grip the workpiece wk. have.

  The stay 6, the non-work side first arm portion 31, the non-work side first auxiliary arm portion 33, and the support arm portion 35 cause the support arm portion 35 to move to the arrow CD in accordance with the rotation of the non-work side first arm portion 31. The parallelogram support link mechanism, which is a parallelogram that guarantees movement in the arrow CD direction perpendicular to the moving direction (arrow AB direction) and the moving direction of the movable gripping portion 40 in the direction along the direction. Is configured.

  That is, the parallelogram support link mechanism is configured to support arms according to the rotation of the non-work side first arm portion 31 while maintaining the parallel state of the stay 6, the base portion 40k of the movable gripping portion 40, and the support arm portion 35. The movement of the part 35 in the arrow AB direction and the arrow CD direction is guaranteed.

  Therefore, the parallelogram support link mechanism maintains the parallel state of the base 40k of the movable side gripping portion 40 and the support arm portion 35, that is, the fixed side gripping portion 50 of the workpiece contact portion 40h of the movable side gripping portion 40. Has a support function for moving in the direction of the arrow AB while maintaining the orientation with respect to the workpiece contact portion 50h.

<Operation of link type electric gripper device>
The operation of gripping the workpiece wk and the operation of releasing the workpiece wk by the movable side gripping portion 40 and the fixed side gripping portion 50 of the gripping portion 4 in the link type electric gripper device 1 having such a configuration will be described.

  In the link type electric gripper device 1, when the workpiece wk is gripped by the workpiece abutting portion 40h of the movable side gripping portion 40 and the workpiece abutting portion 50h of the fixed side gripping portion 50 in the gripping portion 4, the workpiece abutting portion 40h and It starts from a workpiece released state in which the workpiece wk is not gripped by the workpiece contact portion 50h.

  That is, when the work side first arm portion 21 and the non-work side first arm portion 31 are substantially in the arrow AB direction due to the rotation of the first gear 12 and the second gear 13, the movable side grip portion 40 The distance between the workpiece contact portion 40h and the workpiece contact portion 50hc of the fixed side holding portion 50 is maximized, and the workpiece is released without holding the workpiece wk.

  Thereafter, when the work-side first arm portion 21 and the non-work-side first arm portion 31 rotate and approach the state along the arrow CD direction, they are parallel according to the rotation of the non-work-side first arm portion 31. The support arm portion 35 of the quadrilateral support link mechanism moves in the direction of arrow C and moves in the direction of arrow A while maintaining a parallel state with the stay 6 and the base portion 40k of the movable gripping portion 40. That is, the support arm part 35 is moved simultaneously in the directions of the arrows C and A as a whole while drawing one end part 35 a in an arc according to the rotation of the non-work side first arm part 31.

  At this time, the non-work side second auxiliary arm portion 34 of the parallelogram link mechanism falls down along the arrow CD direction together with the non-work side second arm portion 32, but the non-work side second arm portion 32 and Since the parallel state of the base 40k of the movable side gripping part 40, the support arm part 35, and the stay 6 is maintained, the workpiece contact part 40h of the base part 40k moves in the direction of arrow A. Move linearly toward.

  As a result, the workpiece contact portion 40h of the movable gripping portion 40 comes closer to the workpiece contact portion 50h of the fixed grip portion 50 of the main body 3, and the workpiece contact portion 40h and the workpiece contact portion 50h Thus, the workpiece wk can be gripped by abutting and pinching one end and the other end of the workpiece wk.

  Next, in the link type electric gripper device 1, when releasing the workpiece wk from the workpiece gripping state in which the workpiece wk is gripped by the movable side gripping portion 40 and the fixed side gripping portion 50 in the gripping portion 4, The side first arm portion 31 changes in the direction of the arrow AB by rotating in the opposite direction to when the workpiece wk is gripped.

  At this time, in accordance with the rotation of the non-work side first arm portion 31, the support arm portion 35 of the parallelogram support link mechanism maintains the parallel state with the stay 6 and the base portion 40k of the movable side grip portion 40 in the arrow D direction. And move in the direction of arrow B. That is, the support arm portion 35 is moved simultaneously in the direction of the arrow D and the direction of the arrow B as a whole while drawing one end portion 35 a in an arc according to the rotation of the non-work side first arm portion 31.

  At this time, the non-work side second auxiliary arm portion 34 of the parallelogram link mechanism gradually rises together with the non-work side second arm portion 32 from the state of falling in the direction along the arrow CD direction. Since the parallel state with the second arm portion 32 is maintained, the workpiece contact of the base portion 40k is maintained while the parallel state with the base portion 40k of the movable gripping portion 40, the support arm portion 35, and the stay 6 is maintained. The contact portion 40h moves linearly in the direction of arrow B.

  As a result, the workpiece contact portion 40h of the movable gripping portion 40 moves in a direction away from the workpiece contact portion 50h of the fixed gripping portion 50 of the main body 3, and the workpiece contact portion 50h is moved away from the workpiece contact portion 50h. Since 40h separates, the workpiece wk sandwiched and gripped by the workpiece contact portion 40h and the workpiece contact portion 50h can be released.

  By the way, the workpiece contact portion 40h of the movable gripping portion 40 moves linearly in the direction of the arrow AB in accordance with the rotation of the workpiece side first arm portion 21 and the non-work side first arm portion 31. When the arm portion 21 and the non-work side first arm portion 31 are rotating at an angle substantially along the arrow CD direction, the rotation of the work side first arm portion 21 and the non-work side first arm portion 31 is the work contact. This greatly contributes to the movement of the contact portion 40h in the direction of the arrow AB, so that the movement speed of the workpiece contact portion 40h is increased.

  On the other hand, when the workpiece side first arm portion 21 and the non-work side first arm portion 31 are rotated at an angle substantially along the arrow AB direction, the workpiece side first arm portion 21 and the non-work side first arm portion 21 are rotated. Since the rotation of the one arm portion 31 hardly contributes to the movement of the workpiece contact portion 40h in the arrow AB direction, the moving speed of the workpiece contact portion 40h is slowed down.

  Here, as shown in FIGS. 9 and 10, the arrow AB direction in which the movable gripping portion 40 moves is the x axis, the arrow CD direction is the y axis, and the rotation center axis of the first gear 12 is the origin O (0 , 0), and the arm length from the origin O (0, 0) to the position Q of the tip 21b of the work-side first arm 21 is defined as the radius r of the virtual circle CR, and the origin O (0, 0) Assuming that the movable gripping portion 40 is a gripping point P (x, 0), the gripping point P (x, 0) of the movable gripping portion 40 moves on the x axis.

The motion model at the gripping point P (x, 0) of the movable gripping portion 40 can be expressed as a crank motion as shown in FIG. Here, the angle with respect to the x axis when the work side first arm portion 21 rotates is θ, and the gripping point P (x, x) of the movable side gripping portion 40 from the position Q of the tip end portion 21b of the work side first arm portion 21 is set. 0), that is, the arm length of the work-side second arm portion 22 is L, this motion model is expressed by the following (Equation 1) by the cosine theorem.

When this (Equation 1) is transformed into a quadratic equation, it is expressed by the following (Equation 2).

For this (Equation 2), using the formula for the solution of the quadratic equation (x = (− b ± √ (b ² −4ac)) / 2a at ax ² + bx + c = 0) When the position x is obtained, it is expressed by the following (Equation 3).

When this (Expression 3) is expanded, it is expressed as (Expression 4).

Since the arm length L of the work-side second arm portion 22 is greater than the arm length r of the work-side first arm portion 21, x> 0, whereby the position x in (Expression 4) is finally set to the following (Expression It is expressed as 5).

In the rotational motion with a constant angular velocity ω, the angle θ when the work-side first arm portion 21 rotates is expressed as θ = ωt in relation to the time t. Is differentiated by time t, the moving speed v of the gripping point P (x, 0) of the movable gripping portion 40 can be obtained, and this moving speed v is expressed by the following (Equation 6).

  Therefore, when the angle θ (= ωt) when the work side first arm portion 21 rotates is 0 degree, the moving speed v of the gripping point P (x, 0) of the movable gripping portion 40 is also 0 m / sec. The angle θ (= ωt) gradually becomes faster as it approaches 90 degrees, and gradually becomes slower as the angle θ (= ωt) approaches 180 degrees.

By the way, the gripping force (work rate) U with respect to the workpiece wk at the gripping point P (x, 0) of the movable gripping portion 40 is τ, and the torque along the X axis of the movable gripping portion 40 is F. Then, it is expressed by the following (Expression 7).

Therefore, the thrust F is expressed by the following (formula 8).

  According to (Expression 7) and (Expression 8), when the angle θ (= ωt) when the work-side first arm portion 21 rotates is around 90 degrees, the gripping point P (x, 0) of the movable gripping portion 40 is obtained. ) Is fast and the gripping force (working power) U for the workpiece wk is the smallest. As the angle θ (= ωt) when the work-side first arm portion 21 rotates moves away from 90 degrees, the moving speed v at the gripping point P (x, 0) of the movable-side gripping portion 40 decreases, but the workpiece Grasping force (power) U with respect to wk gradually increases.

  Thus, if the angle θ when the workpiece side first arm portion 21 rotates is in the range of about 45 degrees to 135 degrees, the workpiece can be practically used while moving the movable side gripping portion 40 with respect to the fixed side gripping portion 50. The workpiece wk can be released by gripping wk.

<Effect of link type electric gripper device>
In the link type electric gripper device 1, the rotation of the motor shaft 2 a of the motor 2 is performed through the gear mechanisms of the motor gear 11, the first gear 12 and the second gear 13, and the two work side first arm portions 21 and the non-work side first When transmitted to the arm part 31, the two work-side first arm parts 21 and the non-work-side first arm part 31 that face each other on the outside of the main body part 3 rotate with their rotation directions opposite to each other. To do.

  At this time, the two work side first arm portions 21 and the non-work side first arm portion 31, the two work side second arm portions 22 and the non-work side second arm portion 32, and the connecting pin 37 form a rhombus link mechanism. Since it is configured, the movable gripping portion 40 fixed to the connecting pin 37 moves linearly so as to approach or separate from the fixed gripping portion 50.

  Accordingly, the workpiece wk can be gripped or released by the workpiece contact portion 40h of the movable gripping portion 40 and the workpiece contact portion 50h of the fixed gripping portion 50. Thus, the link-type electric gripper device 1 does not use a linear guide for linearly sliding a gripping member as in the conventional electric gripper device, and thus is small and has a simple configuration, The movable side grip 40 can be linearly moved with respect to the grip 50.

  Further, in the link type electric gripper device 1, as shown in FIG. 9, when the non-work side first arm portion 31 rotates, the tip end portion 31 b may mechanically interfere with the tip end portion 6 a of the stay 6. Therefore, the stroke range when the movable gripping member 40 moves linearly can be lengthened.

  As a result, the link type electric gripper device 1 has a stroke of the movable side gripping portion 40 without increasing the size of the stroke range of the gripping member using the conventional cam member without being limited to the radius range of the cam member. The range can be extended. Thus, the link type electric gripper device 1 can be easily gripped even when the workpiece wk is larger than the conventional one.

  Furthermore, the link type electric gripper device 1 arbitrarily increases the arm lengths of the work side first arm part 21, the non-work side first arm part 31, the work side second arm part 22, and the non work side second arm part 32. Only by setting, the stroke range for gripping or releasing the workpiece wk can be further increased with a simple configuration without changing the basic structure of the rhombus link mechanism.

<Other embodiments>
In the above-described embodiment, the movable grip 40 is supported by the connecting pins 37, 38, and the fixed grip 50 is provided on the outer side surface 3 a of the main body 3 facing the movable grip 40. However, the present invention is not limited to this, and the movable grip 40 is provided so as to cover the entire connecting pins 37 and 38, and the fixed grip is provided on the top surface of the main body 3. You may do it. In this case, the movable gripping portion and the fixed gripping portion do not jump out from the outer side surface, so that the link type electric gripper device 1 can be further reduced in thickness.

  Moreover, in embodiment mentioned above, the rotation part of the work side 1st arm part 21 and the work side 2nd arm part 22 and the non-work side 1st arm part 31 and the non-work side 2nd arm part 32 of Although the case where the rotating part or the like is supported by the bearing has been described, the present invention is not limited thereto, and the bearing part may be sealed by a seal member (not shown).

  In this case, it is possible to prevent foreign matters such as grease, abrasion powder and dust from coming out without increasing the size compared to the case of using bellows, etc., so that it is environmentally friendly and the use conditions of clean rooms are severe. The link type electric gripper device 1 can be used even in an environment.

  Further, in the above-described embodiment, the case where the movable side gripping part 40 and the fixed side gripping part 50 for gripping the rectangular workpiece wk are provided has been described. A movable-side gripping part and a fixed-side gripping part having an arc shape for gripping a workpiece having a shape may be provided, or a movable-side gripping part and a fixed-side gripping part adapted to the shape of the work may be provided.

  The case where the electric gripper device of the present invention is used for automatic product assembly, component transportation, inspection, etc. in an FA (Factory Automation) assembly process has been described. However, the present invention is not limited to this, and it can be used for a food topping process, an optical equipment alignment automation process, and a robot tip gripper in the medical and drug discovery markets.

  DESCRIPTION OF SYMBOLS 1 ... Link-type electric gripper apparatus (electric gripper apparatus), 2 ... Motor, 2a ... Motor shaft, 3 ... Main part, 4 ... Grasping part, 6 ... Stay, 6a ... Tip part, 11 ... ... motor gear, 12 ... 1st gear, 13 ... 2nd gear, 21, 31 ... work side first arm (first arm), 21a, 31a ... base end, 21b, 31b ... tip Part, 22, 32... Work side second arm part (second arm part), 22a, 32a .. base end part, 22b, 32b .. tip part, 33... Non-work side first auxiliary arm part, 34 ... non-work side second auxiliary arm (auxiliary arm), 35 ... support arm, 37, 38 ... connecting pin, 40 ... movable side holding part (first holding part), 50 ... fixed side Grasping part (second gripping part), wk: Workpiece.

Claims (4)

A motor,
A main body having a built-in gear mechanism for transmitting rotation of the motor shaft of the motor;
Two first arm portions that are rotationally driven via the gear mechanism and are disposed opposite to each other with the main body portion interposed therebetween on the outer side of the main body portion so that the rotation directions thereof are opposite to each other.
Two distal arm portions of which the distal end portions of the two first arm portions and the proximal end portions thereof are rotatably supported;
A connecting pin that rotatably connects the tip ends of the two second arm parts;
A first gripping part fixed to the connecting pin;
A second gripping part fixed at a position facing the first gripping part on the main body part separated from the first gripping part by a predetermined distance and gripping a workpiece with the first gripping part. An electric gripper device. An auxiliary arm portion that operates following the second arm portion while maintaining a state parallel to any one of the two second arm portions, is further provided.
The electric gripper device according to claim 1, wherein the auxiliary arm portion is supported by the first gripping portion. While maintaining the parallel state of the one second arm part and the auxiliary arm part, the two base end parts are rotatably supported, and the moving direction of the first gripping part and the moving direction are orthogonal to each other. The electric gripper device according to claim 2, further comprising a support arm portion movably provided in an orthogonal direction. The gear mechanism is
A bevel gear structure motor gear fixed to the tip of the motor shaft of the motor;
The shaft has a rotation center axis orthogonal to the rotation center axis of the motor gear, is engaged with the motor gear in a state of being opposed to each other, and is rotated in a state where the rotation directions are opposite to each other according to the rotation of the motor gear. A first gear and a second gear having a gear structure are provided, and the two first arm portions are fixed to the first gear and the second gear. The electric gripper device described in 1.