JP2007146997A - Parallel holding mechanism - Google Patents

Abstract

Provided is a parallel holding mechanism which can avoid a link interference, can secure a relatively large work area, can be easily assembled with a reduced number of parts, and can reduce manufacturing costs.
A parallel holding mechanism includes a pulley having a diameter of a predetermined length d and a pulley having a diameter d, and a pulley having a diameter d that is fixed at a position where the rotation joint is held parallel to the rotation joint. 12b, a link 14 that connects both pulleys in a freely rotatable state, and a timing belt 16 that connects both pulleys and rotates both pulleys synchronously. In a fixed state, the longitudinal directions of both rotary joints are parallel to each other. When both pulleys are rotated by the timing belt 16, the longitudinal directions of both rotary joints are always parallel in the yz plane, so that the same movement as that of the parallel link mechanism can be realized. The parallel holding mechanism 10 is used as the three-degree-of-freedom space translation parallel holding mechanism 30.
[Selection] Figure 1

Description

  The present invention relates to a parallel holding mechanism in which two rotary joints hold a state parallel to each other.

  In recent years, research on a parallel mechanism has been underway. The parallel mechanism has a structure in which a plurality of links are connected in parallel from a base part to an end plate part. The simplest parallel mechanism includes a parallelogram link mechanism (or simply a parallel link mechanism) composed of four links.

  As a three-degree-of-freedom spatial translation parallel mechanism, there is a Delta mechanism proposed by Clavel et al. (See Patent Document 1). In Patent Document 1, a ball joint (ball-and-socket) is used for the connection between two parallel linking bars and the tip of the arm extending from the base and the connection between the linking bar and the movable element (hand end). joints) is used. With the above configuration, a parallel mechanism in which the hand portion is always parallel to the base portion is realized.

  On the other hand, as another three-degree-of-freedom space translation parallel mechanism, there is a mechanism proposed by Tsai et al. (See Patent Document 2). In Patent Document 2, a parallel link mechanism is used, and a revolute joint is used for connection between the parallel link mechanism and the arm and between the parallel link mechanism and the platform (hand portion). The mechanism of Patent Document 2 realizes a relatively wider work area than the Delta mechanism of Patent Document 1 using a ball joint.

  FIG. 9 shows a conventional spatial translation parallel mechanism 70 with three degrees of freedom shown in Non-Patent Document 1. The spatial translation parallel mechanism 70 shown in FIG. 9 is a part of a 6-DOF haptic interface that presents a sense of touch, and reference numerals 71a, 71b, and 71c are provided above them. It is a part for supporting another mechanism (not shown) for the haptic interface, and is not particularly related to the function of the spatial translation parallel mechanism 70. In FIG. 9, reference numeral 77 is a base portion, 76 is a motor fixed to the base portion 77, 79 is a link connected to a motor shaft 76 '(not shown) of the motor 76, 74a is a link 79a to a link 75a (not shown). 78a is a link attached to one end of the link 75a by a joint 74c, 78b is a link attached to the other end of the link 75a by a joint 74d, and 75b is a link 78a. A link attached to one end by a joint 74e and a link 78b attached to the other end by a joint 74f, 74b a joint provided on the link 75b, 72 a hand part (a triangular plate indicated by a dotted line), and 73 a hand part 72 And a joint 74b.

  As shown in FIG. 9, the parallel link mechanism A is constituted by the link 75a, the link 78a, the link 78b, and the link 75b. The other two parallel link mechanisms B (left side in FIG. 9) and C (right rear side in FIG. 9) are similarly configured. When the motor 76 rotates and the link 79 is driven via the motor shaft 76 ', the parallel link mechanism A operates, and the other two parallel link mechanisms B and C also operate by this operation. That is, when one motor 76 rotates, all the parallel link mechanisms A, B, and C operate. In this case, since the portion corresponding to the link 79 of the parallel link mechanisms B and C is not driven, the hand portion 72 performs a translational motion with one degree of freedom while being always parallel to the base portion 77. Therefore, by rotating the three motors of the parallel link mechanisms A, B, and C, the hand portion 72 can perform a translational motion with three degrees of freedom while being always parallel to the base portion 77.

  FIG. 10 shows a degree of freedom arrangement regarding the parallel link mechanism A of the space translation parallel mechanism 70. In FIG. 10, the same reference numerals as those in FIG. In FIG. 10, the hand portion 72 is called a traveling plate (traveling plate), the base portion 77 is called a base, and the link 79 having one degree of freedom connected to the base is called an arm. The links 78a and 78b connecting with the traveling plate are called rods. The hand portion 72 and the fixing portion 73 may be collectively referred to as a traveling plate. The joint 74a and the like are shown in a cylindrical shape with one degree of freedom of rotation, and seven joints of the joints 74a to 74f and the motor shaft 76 'are used for the parallel link mechanism A. A three-degree-of-freedom space translation parallel mechanism 70 is configured by connecting a pair of arms and rods in parallel (three parallel link mechanisms A, B, and C) between the base and the traveling plate.

US Pat. No. 4,976,582 US Pat. No. 5,656,905 Yuichi Tsumaki, 5 others, “Development of a small 6-DOF haptic interface”, Journal of the Robotics Society of Japan, The Robotics Society of Japan, May 2005, Vol. 23, No. 4, p. 92-99

  The above-described Delta mechanism proposed by Claver et al., The mechanism proposed by Tsai et al., And the spatial translation parallel mechanism 70 all realized a spatial translation parallel mechanism with three degrees of freedom using a parallel link mechanism. However, when the parallel link mechanism is used, it is impossible to avoid link interference in which the rod interferes with other parts and the inclination (or rotation) angle of the rod is limited. For this reason, there is a problem that the work area of the spatial translation parallel mechanism having three degrees of freedom is greatly limited.

  All of the conventional parallel mechanisms described above have a large number of parts such as joints and are not easy to assemble, resulting in an increase in manufacturing cost.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a parallel holding mechanism capable of avoiding link interference and ensuring a relatively large work area.

  A second object of the present invention is to provide a parallel holding mechanism that has a small number of parts, is easy to assemble, and can reduce manufacturing costs.

  The parallel holding mechanism of the present invention has a predetermined length, a rotatable first rotating portion to which the first rotary joint is fixed, a diameter equal to the predetermined length, and a first diameter. A rotatable second rotating part having a second rotating joint fixed at a position that holds parallel to the first rotating joint, and the first rotating part and the second rotating part are connected in a rotatable state. And a connecting portion that connects the first rotating portion and the second rotating portion and rotates both rotating portions in synchronization with each other.

  Here, in the parallel holding mechanism of the present invention, a base portion connected to the first rotary joint via an arm, and a position connected to the second rotary joint and held parallel to the base portion, and And a hand portion that performs a translational motion with three degrees of freedom.

  Here, in the parallel holding mechanism of the present invention, the first rotating part and the second rotating part may be pulleys, and the connecting part may be a timing belt.

  Here, in the parallel holding mechanism of the present invention, the first rotating portion and the second rotating portion are pulleys, and the connecting portion can be a tape-shaped metal belt fixed on the pulley.

  Here, in the parallel holding mechanism of the present invention, the first rotating part and the second rotating part may be gears, and the connecting part may be a metal chain.

  Here, in the parallel holding mechanism of the present invention, the first rotating part and the second rotating part may be pulleys, and the connecting part may be a wire.

  The parallel holding mechanism of the present invention has a predetermined length of a diameter, a pulley to which the rotary joint is fixed, a diameter of a length equal to the predetermined length, and a position that holds the parallel to the rotary joint. Another pulley to which another rotary joint is fixed, a link to which both pulleys are connected in a rotatable state, and a timing belt that connects both pulleys and rotates both pulleys in synchronization are provided. Since both pulleys have the same diameter, the rotation angle of both pulleys by the timing belt is always equal. As a result, the timing belt can rotate both pulleys synchronously. Both rotary joints are fixed to the respective pulleys, and in this fixed state, the longitudinal directions of the rotary joints are kept parallel to each other. For this reason, when both pulleys are rotated by the timing belt, the longitudinal directions of both rotary joints are always parallel. That is, according to the parallel holding mechanism of the present invention, the movements of the two rotary joints are always held in a parallel state, so that the same movement as that of the parallel link mechanism can be realized. .

  According to the three-degree-of-freedom spatial translational parallel holding mechanism using the parallel holding mechanism of the present invention, the traveling plate connected to one rotary joint via a fixed portion is connected to the other rotary joint via an arm. 3 degrees of freedom of translational motion can be performed while always maintaining parallelism with respect to the base. In the three-degree-of-freedom space translation parallel holding mechanism, the link interference that the inclination (rotation) angle of both rotary joints is limited due to interference with other parts does not occur structurally. Therefore, there is an effect that it is possible to realize a three-degree-of-freedom space translation parallel holding mechanism that can avoid interference of links and can secure a very large work area. The parallel holding mechanism is composed of only two pulleys, a timing belt and a link. For this reason, the number of parts can be reduced significantly compared with the conventional three-degree-of-freedom spatial translation parallel mechanism, the assembly is easy, and the three-degree-of-freedom spatial translation parallelism can be significantly reduced. There is an effect that a holding mechanism can be provided.

  Hereinafter, each embodiment will be described in detail with reference to the drawings.

  FIG. 1 shows a front view of a parallel holding mechanism 10 in Embodiment 1 of the present invention. In FIG. 1, the yz plane is shown, and the x-axis is assumed to be the forward direction in the drawing. In FIG. 1, reference numeral 12a has a diameter (or radius) of a predetermined length d with the center being Pa, a pulley (first rotating portion) that rotates freely around the x axis, and 12b has a center Pb, and the pulley 12a A pulley (second rotating portion) having a diameter d equal to the predetermined length d and rotating freely around the x axis, and a pulley 12a and a pulley 12b rotating freely around the x axis, respectively. The link (connection part) 16 connected in the state which connects is the timing belt (connection part) which connects the pulley 12a and the pulley 12b, and rotates both pulleys 12a and 12b synchronously. As described above, the parallel holding mechanism 10 includes the pulley 12a, the pulley 12b, the link 14, and the timing belt 16.

  As shown in FIG. 1, when the pulley 12a rotates about the x axis by an angle α, the left side of the timing belt 16 is pulled down by a length corresponding to the angle α in the negative direction (arrow B direction) of the z axis. 12b is rotated about the x axis by an angle α. Along with this, the right side of the timing belt 16 is pulled up by a length corresponding to the angle α in the positive direction of the z-axis (direction of arrow A). Contrary to the above, when the pulley 12a rotates about the x axis by the angle −α, the right side of the timing belt 16 is pulled down in the negative direction of the z axis by a length corresponding to the angle −α, and the pulley 12b is moved to the angle −α. Just rotate. Accordingly, the left side of the timing belt 16 is pulled up by a length corresponding to the angle α in the positive direction of the z axis. Since the pulleys 12a and 12b have the same diameter d, the angles at which the pulleys 12a and 12b rotate by the timing belt 16 are always equal. That is, the timing belt 16 can rotate both pulleys 12a and 12b in synchronization.

  FIG. 2 is a right or left side view of the parallel holding mechanism 10 according to the first embodiment of the present invention. Since the left and right side views are objects, only one side view is shown. In FIG. 2, the xz plane is shown, and the y-axis is assumed to have the forward direction on the drawing as the positive direction. In FIG. 2, the same reference numerals as those in FIG. In FIG. 2, reference numeral 22a denotes a rotary joint (first rotary joint) fixed to the pulley 12a, and 22b denotes a rotary joint (second rotary joint) fixed to the pulley 12b. As shown in FIG. 2, when the pulley 12a rotates by an angle α around the x axis, the rotary joint 22a fixed to the pulley 12a also rotates by an equal angle α. The same applies to the rotary joint 22b. When the pulley 12b rotates by an angle α around the x axis, the rotary joint 22b fixed to the pulley 12b also rotates by an equal angle α.

  FIG. 3 is a rear view of the parallel holding mechanism 10 according to the first embodiment of the present invention. In FIG. 3, the yz plane is shown, and the x-axis is assumed to have a positive direction in the depth direction on the drawing. In FIG. 3, portions denoted by the same reference numerals as those in FIG. 1 or FIG. As shown in FIG. 3, the rotary joint 22b is fixed at a position where the rotary joint 22b is kept parallel to the rotary joint 22a. The rotary joint 22b may be fixed at any position on the pulley 12b as long as the rotary joint 22b can hold parallel to the rotary joint 22a. FIG. 3 shows a simple fixing example for convenience of explanation. As illustrated in FIG. 3, the rotary joint 22a having a length j passes through the center Pa of the pulley 12a and is fixed in the diameter direction of the length d, and the rotary joint 22b having the length j also has a center Pb of the pulley 12b. It is fixed in the diameter direction of the length d. With both rotary joints 22a and 22b fixed to the respective pulleys 12a and 12b, the longitudinal direction of the rotary joint 22a (the direction parallel to the y-axis in FIG. 3) and the longitudinal direction of the rotary joint 22b are parallel to each other. It has become. The rotational joint 22b may be fixed at any position on the pulley 12b as long as the rotational joint 22b is deviated from the position shown in FIG. Similarly, the rotation joint 22a may be fixed at any position on the pulley 12a as long as it is deviated from the position shown in FIG. . As described above, as a result of the longitudinal direction of the rotary joint 22a and the longitudinal direction of the rotary joint 22b being parallel to each other, when the pulleys 12a and 12b are rotated by the timing belt 16, the longitudinal direction of the rotary joint 22a and the rotary joint The longitudinal direction of 22b is always parallel to the yz plane. That is, since the movements of the two rotary joints 22a and 22b are movements that always maintain a parallel state, the parallel holding mechanism 10 can realize the same movement as that of the parallel link mechanism. In the parallel holding mechanism 10, the link interference that the inclination (rotation) angles of the rotary joints 22a and 22b are limited due to the interference with other parts does not occur structurally. Therefore, the work area of the parallel holding mechanism 10 can be secured extremely large. As described above, the parallel holding mechanism 10 includes only the pulleys 12a and 12b, the timing belt 16, and the link 14. For this reason, compared with the parallel mechanism in the prior art, the number of parts can be extremely reduced, the assembly is easy, and the manufacturing cost can be significantly reduced.

  As shown in FIG. 3, the length j of the rotary joint 22a in the longitudinal direction is smaller than the diameter d of the pulley 12a. However, this is merely an example, and the length j may be set equal to or larger than the diameter d. Of course you can. Similarly, for the rotary joint 22b, the longitudinal length j of the rotary joint 22b is smaller than the diameter d of the pulley 12b. However, this is merely an example, and the length j should be set equal to or larger than the diameter d. Of course you can also. In FIG. 3, the length j of the rotary joint 22a in the longitudinal direction is equal to the length j of the rotary joint 22b in the longitudinal direction, but this is only an example, and the lengths of the two rotary joints are different. Of course, it can be set as follows.

  FIG. 4 is a perspective view of a spatial translational parallel holding mechanism 30 having three degrees of freedom using the parallel holding mechanism 10 according to the first embodiment of the present invention. In FIG. 4, the same reference numerals as those in FIG. 1 or FIG. In FIG. 4, reference numeral 32 denotes a joint having one degree of freedom of rotation, 34 denotes an arm having one degree of freedom of freedom for connecting the joint 32 to the rotary joint 22 a, and 36 denotes a joint 32 connected to the joint 32. A base (base portion) connected to the rotary joint 22a via the arm 34, and a traveling plate (hand portion) 38 connected to the rotary joint 22b via a fixed portion 39. As described above, the parallel holding mechanism 10 holds the rotation joint 22a and the rotation joint 22b in parallel. The spatial translational parallel holding mechanism 30 with three degrees of freedom shown in FIG. 4 maintains the parallelism of the base 36 and the traveling plate 38 via the rotary joint 22a and the rotary joint 22b.

  As shown in FIG. 4, in the space translation parallel holding mechanism 30 having three degrees of freedom, when the joint 32 connected to the base 36 is rotated by a motor (not shown) or the like, the arm 34 is driven and the arm 34 is connected. The rotary joint 22a rotates. As described above, since the movements of the two rotary joints 22a and 22b are movements of the parallel link mechanism that always maintains the parallel state by the timing belt 16, the angle of the rotary joint 22b with respect to the rotary joint 22a is always constant. As a result, the traveling plate 38 connected to the rotary joint 22b via the fixed portion 39 can perform the translational motion of three degrees of freedom while always maintaining the parallelism with respect to the base 36. The holding mechanism 30 can be realized.

  As described above, according to the first embodiment of the present invention, the parallel holding mechanism 10 has the diameter of the predetermined length d, the pulley 12a to which the rotary joint 22a is fixed, and the diameter of the length equal to the predetermined length d. The pulley 12b, to which the rotary joint 22b is fixed at a position where the rotary joint 22a is held parallel to the rotary joint 22a, the link 14 to which the pulley 12a and the pulley 12b are rotatably connected, and the pulley 12a and the pulley 12b. And a timing belt 16 that rotates both the pulleys 12a and 12b synchronously. The rotational joint 22b may be fixed at any position on the pulley 12b as long as the rotational joint 22b is deviated from the position in the diameter direction of the pulley 12b up and down and left and right as long as the rotational joint 22b can be kept parallel to the rotational joint 22a. The same applies to the rotary joint 22a, and the rotary joint 22a may be fixed at any position on the pulley 12a as long as it can hold parallel to the rotary joint 22b. That is, the longitudinal direction of the rotary joint 22a and the longitudinal direction of the rotary joint 22b are parallel to each other. Since both pulleys 12a and 12b have the same diameter d, the angle at which the pulleys 12a and 12b are rotated by the timing belt 16 is always equal. As a result, the timing belt 16 rotates 12a and 12b synchronously. be able to. As a result, when the pulleys 12a and 12b are rotated by the timing belt 16, the longitudinal direction of the rotary joint 22a and the longitudinal direction of the rotary joint 22b are always parallel in the yz plane. That is, the movements of the two rotary joints 22a and 22b are movements that always maintain a parallel state, and thus the movement similar to the movement of the parallel link mechanism can be realized.

  In the three-degree-of-freedom space translation parallel holding mechanism 30, the base 36 is connected to the rotary joint 22 a through the joint 32 and the arm 34 having one degree of freedom of rotation, and the traveling plate 38 is rotated through the fixed portion 39. Connect to the joint 22b. When the joint 32 connected to the base 36 is rotated by a motor (not shown) or the like, the arm 34 is driven, and the rotary joint 22a to which the arm 34 is connected rotates. Since the movements of the two rotary joints 22a and 22b are movements of a parallel link mechanism that always maintains a parallel state by the timing belt 16, the angle of the rotary joint 22b with respect to the rotary joint 22a is always constant. As a result, the traveling plate 38 connected to the rotary joint 22b via the fixed portion 39 can perform a translational motion with three degrees of freedom while keeping parallel to the base 36 at all times. Since the three-degree-of-freedom space translation parallel holding mechanism 30 uses the parallel holding mechanism 10, the link interference in which the inclination angles of the rotary joints 22a and 22b are limited due to interference with other parts is structurally generated. do not do. Therefore, it is possible to realize the spatial translational parallel holding mechanism 30 with three degrees of freedom that can avoid the interference of the link and can ensure a very large work area. The parallel holding mechanism 10 of the three-degree-of-freedom space translation parallel holding mechanism 30 includes only pulleys 12a and 12b, a timing belt 16 and a link 14. For this reason, the number of parts can be reduced significantly compared with the conventional three-degree-of-freedom spatial translation parallel mechanism, the assembly is easy, and the three-degree-of-freedom spatial translation parallelism can be significantly reduced. A retention mechanism can be provided.

  In Example 2, another parallel holding mechanism will be described. FIG. 5A shows a front view of the parallel holding mechanism 40 according to the second embodiment of the present invention. In FIG. 5A, the yz plane is shown, and the x-axis is assumed to be a forward direction on the drawing. In FIG. 5A, reference numeral 42a has a diameter (or radius) of a predetermined length d with the center being Pa, a pulley (first rotating portion) that freely rotates around the x axis, and 42b has a center that is Pb. The pulley 42a has a diameter d equal to the diameter of the predetermined length d of the pulley 42a, and freely rotates around the x axis (second rotating portion), and 14 includes a pulley 42a and a pulley 42b around the x axis. Links (connection portions) 46a and 46b connected in a freely rotating state are tape-like metal belts (connection portions) that connect the pulleys 42a and 42b and rotate the pulleys 42a and 42b in synchronization. . As shown in FIG. 5A, the metal belt 46a is fixed at the Fa point on the pulley 42a and fixed at the Fb point on the pulley 42b. Similarly, the metal belt 46b is fixed at the Fa point on the pulley 42a and fixed at the Fb point on the pulley 42b. As described above, the parallel holding mechanism 40 includes the pulley 42a, the pulley 42b, the link 14, and the metal belts 46a and 46b.

  FIG. 5B shows a front view of the parallel holding mechanism 40 in a rotated state. In FIG. 5B, portions denoted by the same reference numerals as those in FIG. As shown in FIG. 5B, when the pulley 42a rotates around the x axis by an angle β, the metal belt 46a is pulled down by a length corresponding to the angle β in the negative direction (arrow B direction) of the z axis, The pulley 42b is rotated by an angle β around the x axis. Accordingly, the metal belt 46b is pulled up by a length corresponding to the angle β in the positive direction of the z-axis (direction of arrow A). On the contrary, when the pulley 42a rotates around the x axis by an angle −β, the metal belt 46b is pulled down in the negative direction of the z axis by a length corresponding to the angle −β, and the pulley 42b rotates by an angle −β. Let Along with this, the metal belt 46a is pulled up in the positive direction of the z-axis by a length corresponding to the angle β. Since the pulleys 42a and 42b have the same diameter d, the angles at which the pulleys 42a and 42b rotate by the metal belts 46a and 46b are always equal. That is, the metal belts 46a and 46b can rotate both pulleys 42a and 42b in synchronization.

  Although the rear view of the parallel holding mechanism 40 is omitted, as in the first embodiment, the rotary joint 22a fixed to the pulley 42a and the pulley 42b are fixed at positions where the parallel holding mechanism 40 is held parallel to the rotary joint 22a. And a rotary joint 22b. As in the first embodiment, the rotary joint 22b is fixed at any position on the pulley 42b as long as the rotary joint 22b can be kept parallel to the rotary joint 22a even if the rotary joint 22b is displaced vertically and horizontally from the position in the diameter direction of the pulley 42b. May be. The same applies to the rotary joint 22a, and the rotary joint 22a may be fixed at any position on the pulley 42a as long as it is parallel to the rotary joint 22b. The longitudinal direction of the rotary joint 22a and the longitudinal direction of the rotary joint 22b are parallel to each other in a state where both the rotary joints 22a and 22b are fixed to the pulleys 42a and 42b. As a result, when the pulleys 42a and 42b are rotated by the metal belts 46a and 46b, the longitudinal direction of the rotary joint 22a and the longitudinal direction of the rotary joint 22b are always parallel in the yz plane. That is, as in the first embodiment, the movement of the two rotary joints 22a and 22b is a movement that always maintains a parallel state, and therefore the parallel holding mechanism 40 can realize the same movement as that of the parallel link mechanism. . In the parallel holding mechanism 40, the metal belt 46a is fixed to the Fa point on the pulley 42a and the Fb point on the pulley 42b, and the metal belt 46b is fixed to the Fa point on the pulley 42a and the Fb point on the pulley 42b. Therefore, the rotation angle β is limited to ± 90 ° or less. For this reason, when compared with the parallel holding mechanism 10 of the first embodiment, the work area is limited. However, when compared with the parallel link mechanism of the prior art, the work area of the parallel holding mechanism 40 can be ensured to be extremely large while avoiding link interference. Since the metal belts 46a and 46b in the parallel holding mechanism 40 are less elastic than the timing belt 16 in the first embodiment, the synchronization accuracy of the pulleys 42a and 42b is superior to the parallel holding mechanism 10 in the first embodiment. Yes. As described above, the parallel holding mechanism 40 includes only the pulleys 42a and 42b, the metal belts 46a and 46b, and the link 14. For this reason, compared with the parallel link mechanism in the prior art, the number of parts can be extremely reduced, the assembly is easy, and the manufacturing cost can be significantly reduced.

  By using the parallel holding mechanism 40 instead of the parallel holding mechanism 10 of the first embodiment, the spatial translation parallel holding mechanism 30 with three degrees of freedom can be realized as in the first embodiment. Hereinafter, description will be made assuming that the parallel holding mechanism 10 in FIG. 4 is replaced with the parallel holding mechanism 40 shown in FIGS. 5 (A) and 5 (B). In this case, in the space translation parallel holding mechanism 30 having three degrees of freedom, when the joint 32 connected to the base 36 is rotated by a motor (not shown) or the like, the arm 34 is driven, and the rotary joint 22a to which the arm 34 is connected rotates. To do. As described above, since the movements of the two rotary joints 22a and 22b are movements of the parallel link mechanism that always maintains a parallel state by the metal belts 46a and 46b, the angle of the rotary joint 22b with respect to the rotary joint 22a is always constant. Become. As a result, the traveling plate 38 connected to the rotary joint 22b via the fixed portion 39 can perform the translational motion of three degrees of freedom while always maintaining the parallelism with respect to the base 36. The holding mechanism 30 can be realized.

  As described above, according to the second embodiment of the present invention, instead of the timing belt 16 of the first embodiment, the tape-shaped metal belt 46a fixed at the Fa point on the pulley 42a and fixed at the Fb point on the pulley 42b. By using the tape-shaped metal belt 46b fixed at the Fa point on the pulley 42a and fixed at the Fb point on the pulley 42b, another parallel holding mechanism 40 can be realized. In the parallel holding mechanism 40, the metal belt 46a is fixed to the Fa point on the pulley 42a and the Fb point on the pulley 42b, and the metal belt 46b is fixed to the Fa point on the pulley 42a and the Fb point on the pulley 42b. The rotation angle β of the pulley 42a and the like is limited to ± 90 ° or less. For this reason, when compared with the parallel holding mechanism 10 of the first embodiment, the work area is limited. However, when compared with the parallel link mechanism of the prior art, the work area of the parallel holding mechanism 40 can be ensured to be extremely large while avoiding link interference. Since the metal belts 46a and 46b in the parallel holding mechanism 40 are less elastic than the timing belt 16 in the first embodiment, the synchronization accuracy of the pulleys 42a and 42b is superior to the parallel holding mechanism 10 in the first embodiment. Yes. Similar to the parallel holding mechanism 10 of the first embodiment, the parallel holding mechanism 40 can significantly reduce the number of parts, and can be easily assembled, and can significantly reduce the manufacturing cost, as compared with the parallel link mechanism in the prior art. Can do. By using the parallel holding mechanism 40 in place of the parallel holding mechanism 10 of the first embodiment, a spatial translation parallel holding mechanism with three degrees of freedom that can avoid a link interference and secure a very large work area as in the first embodiment. 30 can be realized.

  In Example 3, another parallel holding mechanism will be described. FIG. 6 is a front view of the parallel holding mechanism 50 according to the third embodiment of the present invention. In FIG. 6, the yz plane is shown, and the x-axis is assumed to be the forward direction on the drawing. In FIG. 6, a reference numeral 52a has a diameter (or radius) of a predetermined length d with the center being Pa, a gear (first rotating portion) that freely rotates around the x axis, 52b has a center Pb, and the gear 52a A gear having a length d equal to the diameter of the predetermined length d and rotating freely around the x axis (second rotating portion) 14 is a gear 52a and a gear 52b that rotate freely around the x axis. The link (connection part) 56 connected in the state of connecting is a metal chain (connection part) that connects the gear 52a and the gear 52b and rotates both the gears 52a and 52b in synchronization. As described above, the parallel holding mechanism 50 includes the gear 52a, the gear 52b, the link 14, and the metal chain 56.

  As shown in FIG. 6, when the gear 52a rotates around the x axis by an angle γ, the left side of the metal chain 56 is pulled down by a length corresponding to the angle γ in the negative direction of the z axis (the direction of arrow B). 52b is rotated about the x axis by an angle γ. Along with this, the right side of the metal chain 56 is pulled up by the length corresponding to the angle γ in the positive direction of the z-axis (direction of arrow A). Contrary to the above, when the gear 52a rotates about the x axis by an angle −γ, the right side of the metal chain 56 is pulled down in the negative direction of the z axis by a length corresponding to the angle −γ, and the gear 52b is moved to the angle −γ. Just rotate. Accordingly, the left side of the metal chain 56 is pulled up by a length corresponding to the angle γ in the positive direction of the z axis. Since both gears 52a and 52b have the same diameter d, the angles at which both gears 52a and 52b rotate by the metal chain 56 are always equal. That is, the metal chain 56 can rotate both the gears 52a and 52b synchronously.

  Although the rear view of the parallel holding mechanism 50 is omitted, the rotary joint 22a fixed to the gear 52a and the position on the gear 52b that holds the parallel to the rotary joint 22a are fixed as in the first embodiment. And a rotary joint 22b. As in the first embodiment, the rotary joint 22b is located at any position on the gear 52b as long as the rotary joint 22b can be kept parallel to the rotary joint 22a even if the rotary joint 22b deviates vertically and horizontally from the position in the diameter direction of the gear 52b. It may be fixed. The same applies to the rotary joint 22a. The rotary joint 22a may be fixed at any position on the gear 52a as long as it is parallel to the rotary joint 22b. The longitudinal direction of the rotary joint 22a and the longitudinal direction of the rotary joint 22b are parallel to each other in a state where the rotary joints 22a and 22b are fixed to the gears 52a and 52b. As a result, when the gears 52a and 52b are rotated by the metal chain 56, the longitudinal direction of the rotary joint 22a and the longitudinal direction of the rotary joint 22b are always parallel in the yz plane. That is, as in the first embodiment, the movements of the two rotary joints 22a and 22b are movements that always maintain a parallel state, and therefore the parallel holding mechanism 50 can realize the same movement as that of the parallel link mechanism. it can. In the parallel holding mechanism 50, the link interference in which the inclination (rotation) angles of the rotary joints 22a and 22b are limited due to interference with other components does not occur in the structure. Therefore, the work area of the parallel holding mechanism 50 can be secured extremely large. Since the metal chain 56 in the parallel holding mechanism 50 has little elasticity compared to the timing belt 16 in the first embodiment, the synchronization rigidity of both gears 52a and 52b is superior to the parallel holding mechanism 10 in the first embodiment. As described above, the parallel holding mechanism 50 includes only the gears 52a and 52b, the metal chain 56, and the link 14. For this reason, compared with the parallel link mechanism in the prior art, the number of parts can be extremely reduced, the assembly is easy, and the manufacturing cost can be significantly reduced.

  By using the parallel holding mechanism 50 instead of the parallel holding mechanism 10 of the first embodiment, the spatial translation parallel holding mechanism 30 having three degrees of freedom can be realized as in the first embodiment. Hereinafter, description will be made assuming that the parallel holding mechanism 10 in FIG. 4 is replaced with the parallel holding mechanism 50 shown in FIG. In this case, in the space translation parallel holding mechanism 30 having three degrees of freedom, when the joint 32 connected to the base 36 is rotated by a motor (not shown) or the like, the arm 34 is driven, and the rotary joint 22a to which the arm 34 is connected rotates. To do. As described above, since the movement of the two rotary joints 22a and 22b is a movement of the parallel link mechanism that always keeps the parallel state by the metal chain 56, the angle of the rotary joint 22b with respect to the rotary joint 22a is always constant. As a result, the traveling plate 38 connected to the rotary joint 22b via the fixed portion 39 can perform the translational motion of three degrees of freedom while always maintaining the parallelism with respect to the base 36. The holding mechanism 30 can be realized.

  As described above, according to the third embodiment of the present invention, another parallel holding mechanism 50 is obtained by using the gears 52a and 52b and the metal chain 56 in place of the pulleys 12a and 12b and the timing belt 16 of the first embodiment. Can be realized. In the parallel holding mechanism 50, the link interference in which the inclination (rotation) angles of the rotary joints 22a and 22b are limited due to interference with other components does not occur in the structure. Therefore, the work area of the parallel holding mechanism 50 can be secured extremely large. Since the metal chain 56 in the parallel holding mechanism 50 has little elasticity compared to the timing belt 16 in the first embodiment, the synchronization rigidity of both gears 52a and 52b is superior to the parallel holding mechanism 10 in the first embodiment. Similar to the parallel holding mechanism 10 of the first embodiment and the parallel holding mechanism 40 of the second embodiment, the parallel holding mechanism 50 can significantly reduce the number of parts and can be easily assembled as compared with the parallel link mechanism in the prior art. Yes, the manufacturing cost can be significantly reduced. By using the parallel holding mechanism 50 in place of the parallel holding mechanism 10 of the first embodiment, a spatial translation parallel holding mechanism with three degrees of freedom that can avoid a link interference and secure a very large work area as in the first embodiment. 30 can be realized.

  In Example 4, another parallel holding mechanism will be described. FIG. 7A shows a front view of the parallel holding mechanism 60 in the fourth embodiment of the present invention, and FIG. 7B shows a right side view of the parallel holding mechanism 60. In FIG. 7A, the yz plane is shown, and the x-axis is assumed to be the forward direction on the drawing. In FIG. 7A, reference numeral 62a has a diameter (or radius) of a predetermined length d with the center being Pa, a pulley (first rotating part) that freely rotates around the x axis, and 62b has a center that is Pb. The pulley 62a has a diameter d that is equal to the diameter of the predetermined length d of the pulley 62a and rotates freely around the x axis (second rotating portion), and 14 is a pulley 62a and a pulley 62b each around the x axis. Links (connection portions) 66a and 66b connected in a freely rotating state connect the pulley 62a and the pulley 62b, respectively, and rotate the pulleys 62a and 62b in synchronization. As shown in FIGS. 7A and 7B, after the wire 66a is fixed at the Ga1 point on the pulley 62a, the wire 66a is wound around the pulley 62a clockwise by 3/4 turn, and then on the pulley 62b. After being wound clockwise by 3/4 round, it is fixed at Gb1 point on the pulley 62b. After the wire 66b is fixed at the Gb2 point on the pulley 62b, the wire 66b is wound clockwise on the pulley 62b by 3/4 turn, and then wound clockwise on the pulley 62a by 3/4 turn, then on the pulley 62a. The Ga2 point is fixed. In FIG. 7A, the Ga2 point is in the back of the Ga1 point, and the Gb2 point is in the back of the Gb1 point. As shown in FIG. 7B, the wires 66a and 66b are wound around the pulleys 62a and 62b, respectively. As described above, the parallel holding mechanism 60 includes the pulley 62a, the pulley 62b, the link 14, and the wires 66a and 66b.

  FIG. 8A shows a front view of the parallel holding mechanism 60 in a rotated state, and FIG. 8B shows a right side view of the parallel holding mechanism 60 in a rotated state. In FIG. 8, the same reference numerals as those in FIG. As shown in FIGS. 8A and 8B, when the pulley 62a rotates about the x axis by an angle δ, the wire 66a moves in the negative direction of the z axis (direction of arrow B) by a length corresponding to the angle δ. Pulled down, the pulley 62b is rotated about the x axis by an angle δ. Accordingly, the wire 66b is pulled up by a length corresponding to the angle δ in the positive z-axis direction (arrow A direction). Contrary to the above, when the pulley 62a rotates around the x axis by an angle −δ, the wire 66b is pulled down in the negative direction of the z axis by a length corresponding to the angle −δ, and rotates the pulley 62b by an angle −δ. . Accordingly, the wire 66a is pulled up in the positive direction of the z-axis by a length corresponding to the angle δ. Since the pulleys 62a and 62b have the same diameter d, the angles at which the pulleys 62a and 62b rotate by the wires 66a and 66b are always equal. That is, the wires 66a and 66b can rotate both pulleys 62a and 62b in synchronization.

  Although the rear view of the parallel holding mechanism 60 is omitted, as in the first embodiment, the rotary joint 22a fixed to the pulley 62a and the pulley 62b are fixed to a position that holds the parallel to the rotary joint 22a. And a rotary joint 22b. As in the first embodiment, the rotary joint 22b is fixed at any position on the pulley 62b as long as the rotary joint 22b can be kept parallel to the rotary joint 22a even if the rotary joint 22b is deviated vertically and horizontally from the position in the diameter direction of the pulley 62b. May be. The same applies to the rotary joint 22a, and the rotary joint 22a may be fixed at any position on the pulley 62a as long as it is parallel to the rotary joint 22b. The longitudinal direction of the rotary joint 22a and the longitudinal direction of the rotary joint 22b are parallel to each other with the rotary joints 22a and 22b fixed to the pulleys 62a and 62b. As a result, when the pulleys 62a and 62b are rotated by the wires 66a and 66b, the longitudinal direction of the rotary joint 22a and the longitudinal direction of the rotary joint 22b are always parallel in the yz plane. That is, as in the first embodiment, the movements of the two rotary joints 22a and 22b are movements that always maintain a parallel state, and therefore the parallel holding mechanism 60 can realize the same movement as that of the parallel link mechanism. . In the parallel holding mechanism 60, the wire 66a is fixed to the Ga1 point on the pulley 62a and the Gb1 point on the pulley 62b, and the wire 66b is fixed to the Ga2 point on the pulley 62a and the Gb2 point on the pulley 62b. The rotation angle δ is limited to ± 270 ° or less. For this reason, when compared with the parallel holding mechanism 10 of the first embodiment, the work area is limited. However, when compared with the parallel link mechanism of the prior art, the work area of the parallel holding mechanism 60 can be ensured to be extremely large while avoiding link interference. When compared with the parallel holding mechanism 40 of the second embodiment, the rotation angle increases by ± 180 °, so that the movable range can be further increased. The wires 66a and 66b in the parallel holding mechanism 60 are higher in rigidity than the timing belt 16 in the first embodiment, and have no backlash compared to the metal chain 56 in the third embodiment, so that the synchronization accuracy is high. The wires 66a and 66b are lighter than the metal belt 46a of the second embodiment and the metal chain 56 of the third embodiment. As described above, the parallel holding mechanism 60 includes only the pulleys 62a and 62b, the wires 66a and 66b, and the link 14. For this reason, compared with the parallel link mechanism in the prior art, the number of parts can be extremely reduced, the assembly is easy, and the manufacturing cost can be significantly reduced.

  By using the parallel holding mechanism 60 instead of the parallel holding mechanism 10 of the first embodiment, the spatial translation parallel holding mechanism 30 having three degrees of freedom can be realized as in the first embodiment. Hereinafter, description will be made assuming that the parallel holding mechanism 10 in FIG. 4 is replaced with the parallel holding mechanism 60 shown in FIGS. 7 and 8. In this case, in the space translation parallel holding mechanism 30 having three degrees of freedom, when the joint 32 connected to the base 36 is rotated by a motor (not shown) or the like, the arm 34 is driven, and the rotary joint 22a to which the arm 34 is connected rotates. To do. As described above, since the movement of the two rotary joints 22a and 22b is a movement of the parallel link mechanism that always keeps the parallel state by the wires 66a and 66b, the angle of the rotary joint 22b with respect to the rotary joint 22a is always constant. . As a result, the traveling plate 38 connected to the rotary joint 22b via the fixed portion 39 can perform the translational motion of three degrees of freedom while always maintaining the parallelism with respect to the base 36. The holding mechanism 30 can be realized.

  As described above, according to the fourth embodiment of the present invention, instead of the timing belt 16 of the first embodiment or the metal belt 46a of the second embodiment, it is fixed at the Ga1 point on the pulley 62a and at the Gb1 point on the pulley 62b. By using the fixed wire 66a and the wire 66b fixed at the Ga2 point on the pulley 62a and fixed at the Gb2 point on the pulley 62b, another parallel holding mechanism 60 can be realized. In the parallel holding mechanism 60, the wire 66a is fixed to the Ga1 point on the pulley 62a and the Gb1 point on the pulley 62b, and the wire 66b is fixed to the Ga2 point on the pulley 62a and the Gb2 point on the pulley 62b. The rotation angle β such as 62a is limited to ± 270 ° or less. For this reason, when compared with the parallel holding mechanism 10 of the first embodiment, the work area is limited. However, when compared with the parallel link mechanism of the prior art, the work area of the parallel holding mechanism 60 can be ensured to be extremely large while avoiding link interference. When compared with the parallel holding mechanism 40 of the second embodiment, the rotation angle increases by ± 180 °, so that the movable range can be further increased. The wires 66a and 66b in the parallel holding mechanism 60 are higher in rigidity than the timing belt 16 in the first embodiment, and have no backlash compared to the metal chain 56 in the third embodiment, so that the synchronization accuracy is high. The wires 66a and 66b are lighter than the metal belt 46a of the second embodiment and the metal chain 56 of the third embodiment. Similar to the parallel holding mechanism 10 of the first embodiment, the parallel holding mechanism 60 can significantly reduce the number of parts, can be easily assembled, and can significantly reduce the manufacturing cost as compared with the parallel link mechanism in the prior art. Can do. By using the parallel holding mechanism 60 instead of the parallel holding mechanism 10 of the first embodiment, a spatial translation parallel holding mechanism with three degrees of freedom that can avoid a link interference and secure a very large work area as in the first embodiment. 30 can be realized.

  As an application example of the present invention, as a three-degree-of-freedom spatial translation parallel holding mechanism 30 (or a parallel-holding mechanism 10 in the three-degree-of-freedom spatial translation parallel holding mechanism 30) in a six-degree-of-freedom haptic interface that presents touched intervals. Can be applied. Furthermore, it is also possible to use it for a three-degree-of-freedom translation unit of a robot.

It is a front view of the parallel holding mechanism 10 in Example 1 of this invention. It is the right or left view of the parallel holding mechanism 10 in Example 1 of this invention. It is a rear view of the parallel holding mechanism 10 in Example 1 of this invention. It is a perspective view of the space translation parallel holding mechanism 30 of 3 degrees of freedom using the parallel holding mechanism 10 in Example 1 of this invention. It is a front view of the parallel holding mechanism 40 in Example 2 of this invention. It is a front view of the parallel holding mechanism 40 in the rotated state. It is a front view of the parallel holding mechanism 50 in Example 3 of this invention. It is a figure which shows the parallel holding mechanism 60 in Example 4 of this invention. It is a figure which shows the parallel holding mechanism 60 in the rotated state. It is a figure which shows the conventional space translation parallel mechanism 70 of 3 degrees of freedom shown by the nonpatent literature 1. FIG. It is a figure which shows the freedom degree arrangement | positioning regarding the parallel link mechanism A of the space translation parallel mechanism.

Explanation of symbols

10, 40, 50, 60 Parallel holding mechanism, 12a, 12b, 42a, 42b, 62a, 62b Pulley, 14, 75a, 75b, 78a, 78b, 79 Link (78a and 78b are rods, 79 is an arm), 16 Timing Belt, 22a, 22b rotary joint, 30 3 degrees of freedom spatial translational parallel holding mechanism, 32, 74a, 74b, 74c, 74d, 74e, 74f joint, 34 arm, 36, 77 base (or base), 38, 72 Traveling plate (or hand part), 39, 73 fixed part, 46a, 46b metal belt, 52a, 52b gear, 56 metal chain, 66a, 66b wire, 70 conventional three-degree-of-freedom spatial translation parallel mechanism, 71a, 71b, 71c Other mechanisms for haptic interfaces Portion for obtaining, 76 motor, 76 'motor shaft (or joint).

Claims (6)

A rotatable first rotating part having a predetermined length of diameter and having a first rotating joint fixed thereto;
A rotatable second rotating part having a diameter equal to the diameter of the predetermined length and having a second rotating joint fixed at a position holding parallel to the first rotating joint;
A connecting portion in which the first rotating portion and the second rotating portion are connected in a freely rotatable state;
A parallel holding mechanism comprising a connecting portion that connects the first rotating portion and the second rotating portion and rotates both rotating portions in synchronization. The parallel holding mechanism according to claim 1,
A base part connected to the first rotary joint via an arm, and a hand part connected to the second rotary joint and fixed in a position to keep parallel to the base part and performing a translational motion of three degrees of freedom; A parallel holding mechanism characterized by further comprising:   3. The parallel holding mechanism according to claim 1, wherein the first rotating part and the second rotating part are pulleys, and the connecting part is a timing belt.   3. The parallel holding mechanism according to claim 1, wherein the first rotating part and the second rotating part are pulleys, and the connecting part is a tape-shaped metal belt fixed on the pulleys. Retention mechanism.   3. The parallel holding mechanism according to claim 1, wherein the first rotating part and the second rotating part are gears, and the connecting part is a metal chain. The parallel holding mechanism according to claim 1 or 2, wherein the first rotating part and the second rotating part are pulleys, and the connecting part is a wire.