JP2015127074A - Chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chuck capable of being downsized and accelerated.SOLUTION: A drive source 1 of the chuck includes: a main body part 11; and a movable part 3 capable of moving linearly with respect to the main body part 11. An arm 24 is connected to the movable part 3 of the drive source 1. A support part 28 is fixed to the main body part 11 of the drive source 1. Each of a pair of grasping links 26a, 26b has a first part 41 and a second part 42 connected to each other in an L shape. At the support part 28, bending parts 43 of the pair of grasping links 26a, 26b are rotatably supported via rotary shafts 27a, 27b. The pair of grasping links 26a, 26b is disposed so that the bending parts 43 face inside. At the first parts 41 of the pair of grasping links 26a, 26b, there are provided a pair of grasping parts 4a, 4b for grasping a workpiece. The second parts 42 of the pair of grasping links 26a, 26b are connected to the arm 24 by a pair of intermediate links 25a, 25b.

Description

  The present invention relates to a chuck for gripping a workpiece.

  As a chuck for gripping a workpiece, a chuck is known in which a workpiece is sandwiched between a pair of gripping portions. In a typical chuck, the pair of gripping portions are supported by the chuck body so as to be slidable in the opening / closing direction. The drive mechanism that drives the pair of gripping portions is a combination of a rotary motor and a gear mechanism. However, this typical chuck has a problem that the opening / closing speed is slow and it is difficult to reduce the size.

  In order to solve this problem, Patent Document 1 discloses a chuck using an air cylinder and a link mechanism as a drive mechanism for driving a pair of gripping portions instead of a rotary motor and a gear mechanism. The chuck includes a cylinder chamber and a piston that moves linearly in the cylinder chamber. A guide rail extending in a direction orthogonal to the moving direction of the piston is fixed to the cylinder chamber. A pair of gripping portions are guided by the guide rail so as to be movable in the opening and closing direction. A link mechanism is interposed between the piston and the pair of gripping portions. The link mechanism is configured such that when the piston moves in a direction protruding from the cylinder chamber, the pair of gripping portions opens, and when the piston moves in the direction of entering the cylinder chamber, the pair of gripping portions closes.

JP 2011-121754 A

  In recent years, it has been desired to reduce the size and speed of the chuck in order to reduce the working tact time. In the chuck described in Patent Document 1, since the linear motion of the piston is converted into the opening / closing operation of the gripping part using the link mechanism, there is an advantage that the gripping part can be opened / closed at high speed. However, there is a problem that it is difficult to reduce the size of the chuck if the opening / closing stroke of the grip portion is to be ensured.

  Accordingly, an object of the present invention is to provide a chuck that can be reduced in size and speed.

  In order to solve the above-described problems, the present invention provides a main body, a drive source having a movable portion linearly movable with respect to the main body, an arm connected to the movable portion, and the main body. It has a support part to be fixed, a first part and a second part connected to an L-shape, and the bent part is rotatably supported by the support part via a rotation shaft, and the bent part faces inward. A pair of gripping links arranged, a pair of gripping portions provided on the first portion of the pair of gripping links, for gripping a workpiece, one end portion being rotatably connected to the arm and the other end portion And a pair of intermediate links rotatably connected to the second portion of the pair of gripping links.

  According to the present invention, the bent portions of the pair of L-shaped grip links are arranged so as to face inward, and the bent portions are rotatably supported by the support portion via the rotation shaft. The chuck can be downsized while ensuring the opening angle. Since the linear movement of the movable part is converted into the opening / closing operation of the gripping part using the link mechanism, the gripping part can be opened and closed at high speed.

It is a perspective view of the chuck of one embodiment of the present invention. It is a perspective view (a partial sectional view is included) of the linear motor of the chuck of this embodiment. It is detail drawing of the link mechanism of the chuck | zipper of this embodiment. FIGS. 4A and 4B are diagrams showing the opening and closing operation of the chuck according to the present embodiment (FIG. 4A shows a fully opened chuck, FIG. 4B shows a chuck at the stage of starting closing, and FIG. 4C shows a fully closed chuck. Shows the chuck). It is the figure which compared the magnitude | size of the link mechanism by this embodiment and a comparative example (FIG. 5 (a), FIG.5 (c) shows the comparative example which formed the holding | grip link linearly, FIG.5 (b). Shows this embodiment in which the grip link is formed in an L-shape). FIG. 6A and FIG. 6C are diagrams in which the size of the link mechanism is compared between the present embodiment and a comparative example (FIGS. 6A and 6C show a comparative example in which grip links are formed in a straight line, and FIG. Shows this embodiment in which the grip link is formed in an L-shape). It is the figure which compared the magnitude | size of the link mechanism with this embodiment and a comparative example (FIG. 7 (a-1), FIG. 7 (a-2) shows the comparative example which turned the bending part of the holding link to the outer side. FIG. 7B shows this embodiment in which the bent portion of the grip link faces inward). It is the figure which compared the magnitude | size of the chuck | zipper laminated | stacked by this embodiment and the comparative example (FIG. 8 (a-1) shows the front view of a comparative example, FIG.8 (a-2) is a side view of a comparative example. 8 (b-1) shows a front view of the present embodiment, and FIG. 8 (b-2) shows a side view of the present embodiment. It is a front view which shows the other example of the chuck | zipper of this embodiment.

  Hereinafter, a chuck according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a perspective view of a chuck according to an embodiment of the present invention. The chuck of the present embodiment includes a linear motor 1 as a drive source and a pair of left and right claws 4a and 4b as gripping portions for grasping a workpiece. The drive shaft 3 as a movable part of the linear motor 1 is arranged in the vertical direction. A link mechanism 2 is provided below the linear motor 1. When the drive shaft 3 of the linear motor 1 is linearly moved, the claws 4a and 4b are opened and closed by the link mechanism 2. Below, the structure of the linear motor 1 and the link mechanism 2 is demonstrated in order.

  As shown in FIG. 2, the linear motor 1 includes a main body 11 and a drive shaft 3. The drive shaft 3 includes a hollow pipe 12 and a plurality of magnets 13 accommodated in the hollow space of the pipe 12. The magnet 13 is formed in a cylindrical shape and is magnetized in the axial direction. The magnets 13 are arranged so that the same poles face each other. A magnetic pole block 14 made of a magnetic material such as iron is interposed between the magnets 13. The magnet 13 and the magnetic pole block 14 form N poles and S poles alternately in the axial direction on the drive shaft 3.

  The drive shaft 3 is surrounded by a plurality of coils 15 arranged in the axial direction. A magnetic clearance is interposed between the drive shaft 3 and the coil 15. The coil 15 is composed of a three-phase coil composed of U, V, and W phases. The coil 15 is held by the coil holder 16. A substrate 17 for wiring to the coil 15 is provided on the upper surface of the coil holder 16. The coil 15, the coil holder 16, and the substrate 17 are covered with a housing 18 that is resin-molded. The coil 15, the coil holder 16, the substrate 17, and the housing 18 constitute the main body 11 of the linear motor 1.

  End members 19 are provided at both ends of the housing 18 in the axial direction. A sensor 20 (see FIG. 1) for detecting the position of the drive shaft 3 is attached to the end member 19. A bush 21 that guides the movement of the drive shaft 3 in the axial direction is also attached to the end member 19.

  When a three-phase alternating current is passed through the coil 15 of the main body 11, thrust is generated in the axial direction of the drive shaft 3 due to the interaction between the magnetic field generated in the drive shaft 3 and the current flowing in the coil 15. Move in the direction. The linear motor 1 of the present embodiment is characterized by being small and light. By adding the link mechanism 2 to the linear motor 1, a small and light chuck can be obtained.

  The structure of the link mechanism 2 is as follows. As shown in FIG. 1, the link mechanism 2 includes an arm 24 connected to the tip of the drive shaft 3 of the linear motor 1, and a pair of intermediate links 25 a and 25 b rotatably connected to both ends of the arm 24. A pair of grip links 26a and 26b rotatably connected to the intermediate links 25a and 25b and a pair of claws 4a and 4b attached to the grip links 26a and 26b are provided. The grip links 26a and 26b are rotatably supported by a cover 28 serving as a support portion via rotation shafts 27a and 27b. The arm 24, the pair of intermediate links 25 a and 25 b, the pair of grip links 26 a and 26 b, and the pair of claws 4 a and 4 b are symmetrical with respect to the center line of the drive shaft 3.

  As shown in FIG. 3, the arm 24 is elongated in a direction perpendicular to the drive shaft 3. Intermediate links 25 a and 25 b are connected to both ends of the arm 24 in the length direction. A hole 24 a into which the distal end portion of the drive shaft 3 is inserted is formed in the central portion of the arm 24 in the length direction. The arm 24 is fixed to the distal end portion of the drive shaft 3 by a coupling means such as a set screw or a rivet.

  The cover 28 includes a bottom wall 28c fixed to the main body portion 11 of the linear motor 1, and a pair of cover walls 28a and 28b orthogonal to the bottom wall 28c and parallel to each other. The covering walls 28a and 28b are formed in a rectangular shape. The covering walls 28a and 28b cover a part of the arm 24 and a part of the grip links 26a and 26b. Both ends of the rotation shafts 27a and 27b of the grip links 26a and 26b are supported on the cover walls 28a and 28b. Through holes into which the rotary shafts 27a and 27b are inserted are formed in the cover walls 28a and 28b. In order to prevent the axial movement of the rotary shafts 27a and 27b, retaining rings 31 are fitted to both ends of the rotary shafts 27a and 27b.

  The grip links 26a and 26b have a first portion 41 and a second portion 42 that are connected in an L shape. The first part 41 and the second part 42 are formed in a straight line. Claws 4a and 4b as grip portions are detachably attached to the first portion 41, which is the distal end side of the grip links 26a and 26b, by a coupling means such as a screw. The intermediate links 25a and 25b are rotatably connected to the second portion 42 which is the base end side of the L-shaped grip links 26a and 26b. The angle formed between the L-shaped first portion 41 and the second portion 42 is set to 70 ° to 110 ° in this embodiment, but is set to an arbitrary angle less than 180 ° in accordance with the design conditions. be able to. Further, in this embodiment, the claws 4a and 4b and the grip links 26a and 26b are separated, but the claws 4a and 4b and the grip links 26a and 26b can be integrated.

  The bent portions 43 of the grip links 26a and 26b are rotatably supported by the cover 28 via the rotation shafts 27a and 27b. The pair of grip links 26a and 26b are arranged so that the bent portion 43 faces inward. That is, as shown in FIG. 3, when the claws 4 a and 4 b are in the fully open position, the pair of grip links 26 a and 26 b are closest to each other at the bent portion 43.

  The intermediate links 25a and 25b have one end portion rotatably connected to the end portion of the arm 24 via the first link rotation shaft 44, and the other end portion to the second portion 42 of the grip links 26a and 26b. These are rotatably connected via a link rotation shaft 45. The intermediate links 25a and 25b are formed in a U-shaped cross section. The first link rotating shaft 44 passes through the intermediate link 25 a or 25 b and the arm 24, and is prevented from moving in the axial direction by a retaining ring 47. The portion where the retaining ring 47 of the first link rotation shaft 44 is attached is referred to as both ends of the first link rotation shaft 44 in the rotation axis direction. The second link rotation shaft 45 passes through the intermediate link 25a or 25b and the grip link 26a or 26b, and is prevented from moving in the axial direction by the retaining ring 48. The portion of the second link rotation shaft 45 to which the retaining ring 48 is attached is referred to as both ends of the second link rotation shaft 45 in the rotation axis direction.

  When viewed from the axial direction of the rotary shafts 27a, 27b, the second link rotary shaft 45 of the intermediate links 25a, 25b is from lines L1, L2 connecting the first link rotary shaft 44 and the rotary shafts 27a, 27b. (To be precise, a front view of the intermediate links 25a and 25b when viewed from the axial direction of the rotary shafts 27a and 27b is shown in FIG. 7B). This is because when the drive shaft 3 of the linear motor 1 is lowered, the grip links 26a and 26b are closed so that the work is grasped by the claws 4a and 4b. By doing so, even when the power of the coil 15 of the linear motor 1 is turned off and the drive shaft 3 falls due to its own weight, the grip links 26a and 26b are closed, so that the grip links 26a and 26b can be held by the claws 4a and 4b. The workpiece is not dropped and the workpiece is not broken.

  As shown in FIG. 3, the first link rotation shaft 44 and the second link rotation shaft 45 of the intermediate links 25 a and 25 b are disposed outside the cover 28. Even when the claws 4a and 4b are in the fully open position (see FIG. 4 (a)) and when the claws 4a and 4b are in the fully closed position (see FIG. 4 (c)), the first link rotation shaft 44 is provided. The second link rotation shaft 45 is disposed outside the cover 28 and does not overlap the cover 28 in the axial direction. As shown in FIG. 3, the first link rotation shaft 44 and the second link rotation shaft 45 of the intermediate links 25a and 25b protrude in the axial direction from the intermediate links 25a and 25b. The first link rotation shaft 44 and the second link rotation shaft 45 are arranged outside the cover 28 so that the first link rotation shaft 44 and the second link rotation shaft 45 do not overlap the cover 28 in the rotation axis direction. By doing so, the thickness of the cover 28 (thickness in the direction orthogonal to the paper surface of FIG. 3) can be reduced. In this embodiment, not only the first link rotation shaft 44 and the second link rotation shaft 45 but also the intermediate links 25a and 25b are arranged outside the cover 28, but a part of the intermediate links 25a and 25b is provided. May overlap the cover 28.

  FIG. 4 shows the opening / closing operation of the chuck. 4A shows a fully opened chuck, FIG. 4B shows a chuck at the stage of starting to close, and FIG. 4C shows a fully closed chuck. As shown in FIG. 4A, when the drive shaft 3 of the linear motor 1 is raised most, the arm 24 is in the most raised position, and the claws 4a, 4b of the grip links 26a, 26b are in the fully open position.

  As shown in FIG. 4B, when the drive shaft 3 of the linear motor 1 is lowered, the arm 24 is also lowered. The intermediate links 25 a and 25 b connected to both ends of the arm 24 also descend with the arm 24. As the intermediate links 25a and 25b are lowered, the grip links 26a and 26b rotate in the closing direction (1).

  As shown in FIG. 4C, when the drive shaft 3 of the linear motor 1 is further lowered, the arm 24 and the intermediate links 25a and 25b are further lowered, and the grip links 26a and 26b are further rotated in the closing direction. The grip links 26a and 26b rotate until the claws 4a and 4b contact each other.

  With reference to FIG. 5, the reason why the size of the link mechanism 2 can be reduced by forming the grip links 26a and 26b in an L shape will be described. 5 (a) and 5 (c) show a comparative example in which the grip links 26a 'and 26b' are formed in a straight line, and FIG. 5 (b) shows a book in which the grip links 26a and 26b are formed in an L shape. An embodiment is shown. In these drawings, in order to match the design conditions, the opening amount of the grip links 26a, 26b, the boost of the grip links 26a, 26b (the length α from the second link rotating shaft 45 to the rotating shaft 27b and the rotating shaft 27b). To the front end of the grip link 26b is set to 1. When the drive shaft 3 of the linear motor 1 is lowered, the grip links 26a and 26b are closed.

  As shown in the comparative example of FIG. 5A, when the grip links 26a ′ and 26b ′ are formed in a straight line, if the width W of the link mechanism 2 is reduced, the height H becomes longer. As shown in the comparative example of FIG. 5C, when the height H of the link mechanism 2 is to be shortened, the width W becomes wide. As shown in FIG. 5B, the height H and the width W of the link mechanism 2 can be reduced by forming the grip links 26a and 26b in an L shape.

  6 shows the boosting force of the grip links 26a and 26b (ratio of the length α from the second link rotation shaft 45 to the rotation shaft 27b and the length β from the rotation shaft 27b to the tip of the grip link 26b). An example of setting 1.5 is shown. Like FIG.5 (b), FIG.6 (b) shows this embodiment which formed the grip links 26a and 26b in the L-shape. Similar to FIGS. 5A and 5C, FIGS. 6A and 6C show comparative examples in which the grip links 26a ′ and 26b ′ are formed in a straight line.

  When the boosting force of the grip links 26a and 26b is set to 1.5, the distance for moving the grip links 26a and 26b becomes long, but a force of 1.5 times can be obtained from the principle of the lever. As shown in FIG. 6B, the height and width of the link mechanism 2 can be reduced by forming the grip links 26a and 26b in an L shape, even when the boost is set to 1.5. .

  With reference to FIG. 7, the reason why the link mechanism 2 can be reduced in size by turning the bent portions 43 of the pair of grip links 26a, 26b inward will be described. 7 (a-1) and 7 (a-2) show a comparative example in which the bent portions 43 ′ of the grip links 26a ′ and 26b ′ are directed outward, and FIG. 7 (b) shows the grip links 26a, This embodiment is shown with the bent portion 43 of 26b facing inward.

  As shown in the comparative example of FIG. 7A-1, when the bent portions 43 ′ of the pair of grip links 26 a ′ and 26 b ′ are arranged to face outward, the second of the intermediate links 25 a ′ and 25 b ′ The link rotation shaft 45 ′ is easily disposed inside the lines L 1 ′ and L 2 ′ connecting the first link rotation shaft 44 ′ and the rotation shafts 27 a ′ and 27 b ′ of the intermediate links 25 a ′ and 25 b ′. . For this reason, when the drive shaft 3 is lowered, the grip links 26a 'and 26b' are opened. In order to avoid this, as shown in FIG. 7A-2, when the second link rotation shaft 45 ′ of the intermediate links 25a ′ and 25b ′ is arranged outside the lines L1 ′ and L2 ′, The link mechanism 2 is enlarged in the width direction.

  As shown in FIG. 7B, the second link rotation shaft 45 of the intermediate links 25a, 25b is arranged so that the bent portions 43 of the pair of grip links 26a, 26b face inward. , 25b can be easily arranged outside the lines L1 and L2 connecting the first link rotating shaft 44 and the rotating shafts 27a and 27b, and the link mechanism 2 can be downsized.

  Further, as shown in FIG. 7B, the opening angle θ of the grip links 26a and 26b can be increased by turning the bent portions 43 of the grip links 26a and 26b inward. When the opened grip links 26a and 26b rotate in the closing direction, the first portions 41 of the grip links 26a and 26b approach parallel to each other, so that the workpiece can be easily grasped.

  FIG. 8 is a diagram comparing the size of the chuck between this embodiment and the comparative example. FIGS. 8A-1 and 8A-2 show a comparative example in which the first and second link rotation shafts 44 ′ and 45 ′ are arranged inside the cover 28 ′. FIG. 1) and FIG. 8B-2, the first and second link rotating shafts 44 and 45 are arranged outside the cover 28, and the first and second link rotating shafts 44 and 45 overlap the cover 28. This embodiment is configured so as not to become necessary.

  As shown in the front view of the chuck of the comparative example in FIG. 8 (a-1), when the first and second link rotation shafts 44 'and 45' are arranged inside the cover 28 ', the thickness of the cover 28' It is necessary to make the thickness (thickness in the direction perpendicular to the paper surface of FIG. 8A-1) thicker than the axial length of the first and second link rotation shafts 44 'and 45'. As shown in the side view of the stacked chucks in FIG. 8A-2, it is necessary to increase the pitch P1 ′ in the thickness direction between the chucks (in the horizontal direction of the paper surface in FIG. 8A-2).

  On the other hand, as shown in the front view of the chuck according to the present embodiment in FIG. 8 (b-1), the first and second link rotating shafts 44 and 45 are disposed outside the cover 28, and the first and first When the second link rotation shafts 44 and 45 do not overlap the cover 28 in the rotation axis direction, the thickness of the cover 28 (thickness in the direction perpendicular to the paper surface of FIG. 8B-1) is set to the first. And it can reduce to below the length of the axial direction of the 2nd link rotating shaft 44,45. As shown in the side view of the stacked chucks in FIG. 8B-2, the pitch P1 in the thickness direction between the chucks (the left-right direction of the paper surface in FIG. 8B-2) can also be reduced.

  FIG. 9 shows another example of the link mechanism. In this embodiment, the length of the arm 24 is shortened in order to further reduce the size of the link mechanism in the width direction. Further, notches 28a1 and 28b1 are formed in the cover walls 28a and 28b of the cover 28, and the overall shape of the cover walls 28a and 28b is formed in an I shape. By forming the notches 28a1 and 28b1 in the cover walls 28a and 28b of the cover 28, the first and second link rotation shafts 44 and 45 of the intermediate links 25a and 25b are arranged outside the cover walls 28a and 28b. Since the first and second link rotation shafts 44 and 45 can be prevented from overlapping the covering walls 28a and 28b in the rotation axis direction, the thickness of the link mechanism (thickness in the direction perpendicular to the paper surface of FIG. 9). ) Can be made thinner.

  The present invention is not limited to the embodiment described above, and can be embodied in other embodiments without changing the gist of the arrangement of the present invention.

  For example, in the above embodiment, a cylindrical linear motor in which a coil surrounds the drive shaft is used as a drive source, but the structure of the linear motor is not limited to the above embodiment. A flat linear motor in which a coil faces a permanent magnet through a gap as a driving source can also be used.

  In the above-described embodiment, the grip link is closed when the drive shaft of the linear motor is lowered. However, the drive link may be opened when the drive shaft of the linear motor is lowered.

  In the above embodiment, a linear motor is used as the drive source, but a cylinder such as an air cylinder, a hydraulic cylinder, or an electric cylinder can also be used as the drive source.

  In the above embodiment, the example in which the drive shaft of the linear motor is arranged in the vertical direction has been described. However, the drive shaft of the linear motor can be arranged in an arbitrary direction such as a horizontal direction.

  In the above embodiment, an example in which both end portions of the first and second link rotation shafts of the pair of intermediate links do not overlap the cover in the rotation shaft direction has been described. At least one end in the rotation axis direction of the link rotation shaft and / or at least one end in the rotation axis direction of at least one second link rotation shaft of the pair of intermediate links with respect to the pair of gripping links is attached to the cover. It does not have to overlap in the direction of the rotation axis. That is, although there are a total of eight ends of the first and second link rotation shafts, it is sufficient that even one of them does not overlap the cover in the direction of the rotation shaft.

  DESCRIPTION OF SYMBOLS 1 ... Linear motor (drive source), 2 ... Link mechanism, 3 ... Drive shaft (movable part), 4a, 4b ... Claw (gripping part), 11 ... Main part, 24 ... Arm, 25a, 25b ... Intermediate link, 26a , 26b ... gripping link, 27a, 27b ... rotating shaft, 28 ... cover, 28a, 28b ... covering wall, 41 ... first part of gripping link, 42 ... second part of gripping link, 43 ... bent part of gripping link, 44 ... first link rotation axis, 45 ... second link rotation axis

Claims (4)

A driving source having a main body part and a movable part linearly movable with respect to the main body part;
An arm connected to the movable part;
A support part fixed to the body part;
A pair of grip links having a first portion and a second portion connected to an L shape, wherein the bent portion is rotatably supported by the support portion via a rotation shaft, and the bent portion is disposed so as to face inward. When,
A pair of gripping portions provided on the first portion of the pair of gripping links for gripping a workpiece;
A chuck comprising: a pair of intermediate links having one end rotatably connected to the arm and the other end rotatably connected to the second portion of the pair of gripping links. When the movable part of the drive source moves in a direction projecting from the main body part, the pair of gripping links are closed and the pair of gripping parts sandwich the workpiece.
When viewed from the axial direction of the rotating shaft, the second link rotating shaft of the pair of intermediate links with respect to the pair of gripping links is the first link rotating shaft and the rotating shaft of the pair of intermediate links with respect to the arm. The chuck according to claim 1, wherein the chuck is disposed outside a line connecting the two.   At least one end of at least one first link rotating shaft of at least one of the pair of intermediate links with respect to the arm and / or at least one second of at least one of the pair of intermediate links with respect to the pair of gripping links. The chuck according to claim 1, wherein at least one end portion of the link rotation shaft in the rotation axis direction does not overlap the support portion in the axial direction. The said support part is equipped with a pair of cover wall which supports the both ends of the said rotating shaft, and covers at least one part of the said arm and at least one part of the said pair of holding link. The chuck described.

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