Belt drive device

Abstract

Even if the fastening member that fixes the pulley on the moving side for adjusting the axial distance becomes loose, it is possible to prevent the belt from coming off. The adjustment mechanism for adjusting the axial distance between the first pulley and the second pulley includes: a support member on which the first pulley is provided; a first long hole and a second long hole provided in the arm main body; a first bolt that passes through the first long hole and fastens the support member to the arm main body; and a second bolt that passes through the second long hole and fastens the support member to the arm main body. The first long hole has a first length that allows the support member to move in the direction of the second pulley until the axial distance becomes a distance at which the belt can be wound around the first pulley and the second pulley. The second long hole has a second length that maintains the axial distance at a distance at which the belt does not come off from the state of being wound around the first pulley and the second pulley.

Description

Technical Field

[0001] The present invention relates to a belt drive device. Background Art

[0002] Conventionally, as a robot that performs operations such as conveying and mounting semiconductor components, a multi-joint robot having a plurality of arm portions rotatably connected via joints (axes) has been used. In such a robot, there is a robot that transmits the rotation of a driving pulley to a driven pulley using a belt, and rotates a rotating member such as an arm portion using the rotation of the driven pulley (for example, refer to Patent Document 1). Patent Document 1 discloses a mechanism in which one pulley is screwed and fixed using a long hole, so that the axial distance between a pair of pulleys can be adjusted and the tension of the belt can be adjusted.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-074067 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] According to the mechanism for adjusting the axial distance between a pair of pulleys using a long hole, after shortening the axial distance and winding the belt around the pulleys on both sides, the axial distance is extended, so that tension can be applied to the belt. However, if the fastening threaded member passing through the long hole becomes loose, the pulley moves and the axial distance is shortened, and there is a case where the belt comes off the pulley. Therefore, a technique is desired that can prevent the belt from coming off even if the threaded member for fixing the moving pulley for adjusting the axial distance becomes loose.

[0008] Solutions to the Problems

[0009] One technical solution of the present invention relates to a belt drive device, which includes: a first pulley and a second pulley, which are arranged at a specified distance apart and rotatably disposed on the device main body; a belt wound around the first pulley and the second pulley; and an adjustment mechanism provided on the first pulley to adjust the axial distance between the first pulley and the second pulley. The adjustment mechanism includes: a support member that supports the first pulley rotatably; a first long hole provided in at least one of the device main body and the support member, the length direction of the first long hole being along the axial direction connecting the rotation axes of the first pulley and the second pulley; a first fastening member whose rod portion penetrates through the first long hole to fasten the support member to the device main body; a second long hole provided in at least one of the device main body and the support member, the length direction of the second long hole being along the axial direction, and the second long hole being shorter than the first long hole; and a second fastening member whose rod portion penetrates through the second long hole to fasten the support member to the device main body. The first long hole has a first length that enables the support member to move in the direction of the second pulley until the axial distance becomes at least a distance that allows the belt to be wound around the first pulley and the second pulley. The second long hole has a second length that maintains the axial distance at a distance that does not cause the belt to come off from the state of being wound around the first pulley and the second pulley.

[0010] Effects of the Invention

[0011] According to one technical solution, even if the fastening member for fixing the moving-side pulley for adjusting the axial distance becomes loose, it is possible to prevent the belt from coming off. Description of the Drawings

[0012] Figure 1 It is a perspective view of an industrial robot having a wrist rotation part with a belt drive device according to an embodiment of the present disclosure.

[0013] Figure 2 It is a bottom view of the above wrist rotation part.

[0014] Figure 3 It is a side view of the first arm part of the wrist rotation part having a belt drive device according to an embodiment of the present disclosure.

[0015] Figure 4 It is a side view of the arm main body according to an embodiment of the present disclosure.

[0016] Figure 5 It is a perspective view of a support member that supports the first pulley according to an embodiment of the present disclosure.

[0017] Figure 6It is the front view of the first pulley of the embodiment of the present disclosure.

[0018] Figure 7 It is Figure 3 an enlarged view of the adjustment mechanism shown.

[0019] Figure 8 It is a diagram showing the operation of the adjustment mechanism of the embodiment of the present disclosure, and shows a state in which tension is applied to the belt.

[0020] Figure 9 It is a diagram showing the operation of the adjustment mechanism of the embodiment of the present disclosure, and shows a state in which the belt does not come off due to the second pulley.

[0021] Figure 10 It is a diagram showing the operation of the adjustment mechanism of the embodiment of the present disclosure, and shows a state in which the second bolt is removed to loosen the belt so that the belt can be removed from the first pulley.

[0022] Figure 11 It is a diagram for explaining the formula for calculating the length of the long hole of the embodiment of the present disclosure, and shows the ideal installation position of the pulley.

[0023] Figure 12 It is a diagram for explaining the formula for calculating the length of the long hole of the embodiment of the present disclosure, and shows a state in which the first pulley with a small diameter has moved.

[0024] Figure 13 It is a diagram for explaining the formula for calculating the length of the long hole of the embodiment of the present disclosure, and is a diagram showing the pitch circle diameter and the addendum circle diameter of the pulley.

[0025] Figure 14 It is a diagram for explaining the formula for calculating the length of the long hole of the embodiment of the present disclosure, and is a chart showing the relationship between the tension and the elongation rate of the belt. Detailed Embodiments

[0026] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In addition, "substantially" in this specification does not strictly refer to its state, size, direction, orientation, etc., but includes a meaning of an approximate state within a range capable of achieving their functions and effects.

[0027] Figure 1 It is a perspective view showing the appearance of the industrial multi-joint robot 100 of the present embodiment. Figure 2 It is a view of observing the Figure 1 wrist rotation part 105 shown from below. The multi-joint robot 100 is a multi-joint robot having a six-axis degree of freedom structure including a base 101, a rotation part 102, a lower arm part 103, an upper arm part 104, a wrist rotation part 105, a wrist bending part 106, and a wrist rotation part 107.

[0028] As Figure 2 shown, the wrist rotation part 105 includes an arm housing 105a. The arm housing 105a includes a first arm part 2A and a second arm part 2B arranged in parallel with each other. The first arm part 2A and the second arm part 2B respectively constitute side plate parts on both sides of the arm housing 105a. Figure 3 It shows a state where the longitudinal direction E of the arm housing 105a is substantially horizontal.

[0029] As Figure 3 shown, the first arm part 2A includes the belt drive device 1 of the embodiment of the present disclosure.

[0030] The first arm part 2A includes an arm main body 30 that is longer in the front-rear direction (in Figure 3 here, the right side is the front side and the left side is the rear side). The arm main body 30 is an example of the device main body. A wrist bending part 106 is provided at the front end of the arm main body 30. The wrist bending part 106 rotates in the direction of arrow G by the rotation of a second pulley 20 described later. The wrist bending part 106 is an example of a rotating member. In addition, a wrist rotation part 107 that rotates around a rotation axis H is supported at the top end of the wrist bending part 106. At the top end of the wrist rotation part 107, for example, claws (not shown) for gripping components such as semiconductor components are installed.

[0031] The belt drive device 1 of the present embodiment includes a first pulley 10 and a second pulley 20 installed on the arm main body 30, a belt 40 wound around the first pulley 10 and the second pulley 20, and an adjustment mechanism 50.

[0032] A storage part 31 is provided on one side surface of the arm main body 30. The storage part 31 is covered by a cover (not shown). The first pulley 10, the second pulley 20, and the belt 40 are stored in the storage part 31 covered by the cover. Figure 4 It shows the arm main body 30 from which the first pulley 10, the second pulley 20, and the belt 40 are removed from the storage part 31.

[0033] The first pulley 10 is a driving pulley. The second pulley 20 is a driven pulley. The belt 40 is wound around the first pulley 10 and the second pulley 20, and transmits the rotation of the first pulley 10 to the second pulley 20. In the present embodiment, the first pulley 10 and the second pulley 20 are toothed synchronous pulleys. The belt 40 is a toothed synchronous belt that meshes with the teeth of the first pulley 10 and the second pulley 20. In addition, in Figure 13 the other drawings, the illustration of the teeth is omitted.

[0034] The first pulley 10 is disposed at the central portion in the longitudinal direction of the arm main body 30. The longitudinal direction of the arm main body 30 is the same direction as the longitudinal direction E of the first arm portion 2A, and hereinafter is also appropriately referred to as the longitudinal direction E of the arm main body 30. As Figure 5 shown, the first pulley 10 is rotatably supported by a support member 52 of an adjustment mechanism 50 described later. In Figure 3 , the support member 52 is fixed to the back surface of the arm main body 30. The rotation axis of the first pulley 10 rotatably supported by the support member 52 penetrates through a hole 30a of the arm main body 30. As Figure 6 shown, the first pulley 10 has flange portions 14 adjacent to its peripheral surface 12 on both axial sides and preventing the belt 40 from coming off. The first pulley 10 is rotationally driven by a drive unit 19 including a motor as Figure 5 shown.

[0035] The second pulley 20 is disposed at the front end portion of the arm main body 30. The winding diameter of the belt 40 of the second pulley 20 is slightly larger than the winding diameter of the belt 40 of the first pulley 10. The second pulley 20 is rotatably supported by a disk-shaped support plate 21. A speed reducer for reducing the rotation of the second pulley 20 and transmitting it to the wrist bending portion 106 is built in the support plate 21. In Figure 3 , the support plate 21 is fixed to the back surface of the arm main body 30 by a plurality of fixing bolts 22. The rotation axis of the second pulley 20 penetrates through a hole 30b of the arm main body 30. Through holes 30c for the plurality of fixing bolts 22 to penetrate are formed in the arm main body 30. The second pulley 20 also has flange portions adjacent to its peripheral surface on both axial sides and preventing the belt 40 from coming off, similarly to the first pulley 10. The rotation of the second pulley 20 is braked by the first pulley 10 driven by the drive unit 19 via the belt 40.

[0036] As Figure 3 shown, in a state where the first arm portion 2A is substantially horizontal, the first pulley 10 is disposed at a position lower than the second pulley 20. The axial direction (hereinafter also appropriately referred to as the axial direction F) represented by a straight line F connecting the rotation axis of the first pulley 10 and the rotation axis of the second pulley 20 is slightly inclined forward and upward with respect to the longitudinal direction E of the first arm portion 2A.

[0037] As Figure 5 and Figure 7 shown, the adjustment mechanism 50 includes a support member 52 that rotatably supports the first pulley 10, a plurality of first long holes 61 and a plurality of second long holes 62 provided in the arm main body 30, a first bolt 71 penetrating through the first long hole 61, and a second bolt 72 penetrating through the second long hole 62. The first bolt 71 is an example of a first fastening member, and the second bolt 72 is an example of a second fastening member. The first bolt 71 and the second bolt 72 are of the same size.

[0038] The support member 52 is formed by shaping a plate material into a specified shape. In Figure 7 , the support member 52 is fixed to the back surface of the arm body 30 corresponding to the back surface of the arm body 30. The support member 52 is fixed to the arm body 30 by the first bolt 71 and the second bolt 72.

[0039] In Figure 4 , two first elongated holes 61 are formed side by side above the hole 30a. The longitudinal directions of the two first elongated holes 61 are substantially parallel to the longitudinal direction E of the arm body 30, and the two first elongated holes 61 extend in a straight line. Therefore, when the longitudinal direction E of the arm body 30 is set to be substantially horizontal, the longitudinal directions of the two first elongated holes 61 extend along the substantially horizontal direction. The first bolts 71 penetrate through the two first elongated holes 61 respectively. If the arm body 30 is rotated so as to be substantially horizontal and the longitudinal directions of the two first elongated holes 61 extend along the substantially horizontal direction, it is not easy for the support member 52 and the first pulley 10 to deviate and move in any one of the front and rear directions due to gravity. Therefore, it is easy to adjust the tension of the belt 40 described later.

[0040] As Figure 5 shown, two first threaded holes 54 for screwing the first bolts 71 are formed in the support member 52. Annular first sealing members 81 surrounding the first elongated holes 61 are respectively arranged around the two first threaded holes 54. The threaded rod portion 71a of the first bolt 71 penetrates through the first elongated hole 61 from the storage portion 31 side of the arm body 30 and is screwed into the first threaded hole 54 of the support member 52.

[0041] As Figure 4 shown, one second elongated hole 62 is formed on each of the front side and the rear side of the hole 30a ( Figure 4 the right side and the left side in ), for a total of two. When the arm body 30 is in a substantially horizontal state, the second elongated hole 62 on the front side is located above the center of the hole 30a, and the second elongated hole 62 on the rear side is located below the center of the hole 30a. The longitudinal directions of the two second elongated holes 62 are substantially parallel to the longitudinal direction of the first elongated hole 61. The second bolts 72 penetrate through the two second elongated holes 62 respectively.

[0042] As Figure 7As shown, the second longest holes 62 before and after are located near the straight line F indicating the axial direction connecting the rotation axis of the first pulley 10 and the rotation axis of the second pulley 20. In addition, in the side view, the two second longest holes 62 are respectively arranged on both sides of the straight line F. That is, the front second longest hole 62 among the second longest holes 62 before and after is located in the upper region separated by the imaginary plane Fa passing through the straight line F, and the rear second longest hole 62 is located in the lower region of the imaginary plane Fa. In addition, the second longest hole 62 can be completely covered by the seating surface of the head of the second bolt 72. With such an arrangement, the first pulley 10 can be stably fixed by the second bolts 72 respectively passing through the second longest holes 62 before and after.

[0043] As Figure 5 shown, two second threaded holes 56 for screwing in the second bolts 72 are formed in the support member 52. In addition, in Figure 5 one side (rear side), the second threaded hole 56 is blocked by the first pulley 10 and cannot be seen. Annular second sealing members 82 surrounding the second longest holes 62 are respectively arranged around the two second threaded holes 56. The threaded rod portion 72a of the second bolt 72 penetrates through the second longest hole 62 from the storage portion 31 side of the arm portion main body 30 and is screwed into the second threaded hole 56 of the support member 52.

[0044] The first bolt 71 passing through the first longest hole 61 is fastened to the first threaded hole 54, and the second bolt 72 passing through the second longest hole 62 is fastened to the second threaded hole 56, thereby fastening the support member 52 to the arm portion main body 30.

[0045] The first sealing member 81 and the second sealing member 82 are respectively sandwiched between the arm portion main body 30 and the support member 52 and are in close contact with the arm portion main body 30 and the support member 52. The first sealing member 81 surrounds the first longest hole 61 and seals the first longest hole 61, and the second sealing member 82 surrounds the second longest hole 62 and seals the second longest hole 62. Thereby, foreign matters are prevented from invading from the respective longest holes 61, 62 to the storage portion 31 side or the drive portion 19 side.

[0046] The length of the first longest hole 61 is different from the length of the second longest hole 62, and the first longest hole 61 is longer than the second longest hole 62. The length of the first longest hole 61 is, for example, about 1.5 times to 4.0 times the thread diameter of the first bolt 71 and the second bolt 72. The length of the second longest hole 62 is, for example, about 0.5 times to 1.2 times the thread diameter of the first bolt 71 and the second bolt 72.

[0047] In addition, the second longest hole 62 may also have a length that can be completely covered by the seating surface of the head of the second bolt 72.

[0048] By loosening the first bolt 71 and the second bolt 72 that fasten the support member 52 to the arm main body 30, the first pulley 10 can move together with the support member 52 in the longitudinal direction E (front-rear direction) of the arm main body 30. The rod portion 71a of the first bolt 71 is guided by the first long hole 61, and the rod portion 72a of the second bolt 72 is guided by the second long hole 62, so that the support member 52 moves in the longitudinal direction E of the arm main body 30. By moving the first pulley 10 in the front-rear direction, the separation distance between the first pulley 10 and the second pulley 20, that is, the axial distance L between the two pulleys 10 and 20, is displaced.

[0049] In this way, in the present embodiment, by moving the first pulley 10 in the longitudinal direction E of the arm main body 30, the first pulley 10 can move in the axial direction F. This is because, although the axial direction F is slightly inclined with respect to the longitudinal direction E, the degree of inclination is small and does not pose an obstacle to the function of the adjustment mechanism 50, and the axial direction F is substantially along the longitudinal direction E. Therefore, in the description of the present embodiment, there is a case where the longitudinal directions of the first long hole 61 and the second long hole 62 are along the axial direction F.

[0050] In the present embodiment, the first long hole 61 has a first length that enables the support member 52 supporting the first pulley 10 to move in the direction of the second pulley 20 until the axial distance L between the first pulley 10 and the second pulley 20 becomes at least a distance at which the belt 40 can be wound around the respective pulleys 10 and 20. In addition, in the present embodiment, the second long hole 62 has a second length that maintains the axial distance L between the first pulley 10 and the second pulley 20 at a distance that does not cause the belt 40 to come off from the state of being wound around the respective pulleys 10 and 20.

[0051] According to the adjustment mechanism 50 of the present embodiment, the first long hole 61 and the second long hole 62 have the above-mentioned lengths, whereby the belt 40 assumes the following three states.

[0052] As Figure 8 shown, when an appropriate tension is applied to the belt 40, the first bolt 71 and the second bolt 72 are respectively fixed at positions that can move in two directions, forward and backward, with respect to the first long hole 61 and the second long hole 62 (the first state). As Figure 9 shown, for example, when the first bolt 71 and the second bolt 72 become loose and the first pulley 10 moves forward, the second bolt 72 engages with the inner edge of the front end of the second long hole 62 and is restricted from further moving forward. At this time, although the belt 40 becomes slack in the state of being wound around the first pulley 10 and the second pulley 20, it does not come off from the respective pulleys 10 and 20 (the second state). If starting from the state where the first bolt 71 has become loose, as Figure 10When the second bolt 72 is removed as shown, the first pulley 10 can move forward until the first bolt 71 engages with the inner edge of the front end of the first long hole 61 (third state). In this state, the operation of installing and winding the belt 40 around the first pulley 10 and the second pulley 20 can be performed.

[0053] Here, an example of a method for calculating the appropriate length of the second long hole 62 is shown. Figure 11 The ideal mounting positions of a small-diameter pulley (corresponding to the first pulley 10) and a large-diameter pulley (corresponding to the second pulley 20) are shown. Figure 12 The state where the first pulley has moved by L1 in the axial direction F is shown. Figure 13 The state where the belt as a timing belt engages with the small-diameter pulley as a timing pulley is shown.

[0054] In Figure 11 and Figure 12 ,

[0055] When

[0056] L: Approximate axial distance [mm]

[0057] D2: Diameter of the large pulley (second pulley) [mm] [[ID=**27**]]

[0058] D1: Diameter of the small pulley (first pulley) [mm]

[0059] In the case of

[0060] R≈2L+{π(D2+D1) / 2}+{(D2-D1)×(D2-D1) / 4L}.

[0061] As Figure 12 shown, whether the belt disengages from the pulley when the small-diameter pulley has moved by the length of L1 becomes: compared with the approximate belt circumference R1 in the ideal mounting position of the pulley shown in Figure 11 , whether the approximate belt circumference R2 in the circle obtained by adding the tooth height h of the belt to the small-diameter pulley (refer to Figure 13 ) is longer (R2>R1).

[0062] When

[0063] P: Belt pitch (pitch of the belt teeth) [mm]

[0064] N: Number of teeth of the pulley

[0065] PLD (distance between the belt pitch line (BPL) of the belt and the bottom surface of the teeth)

[0066] In the case of

[0067] Figure 13 The pitch diameter of the pulley shown: PD, and the outside diameter of the tooth tip circle: OD are obtained by the following formulas,

[0068] PD = (P × N) / π

[0069] OD = PD - (2 × PLD).

[0070] If the relationship between the belt tension and the belt elongation rate is obtained in advance as shown in the Figure 14 chart shown, then

[0071] When setting

[0072] L3: Geometric tolerance adjustment margin

[0073] α: Required belt elongation rate

[0074] the following holds,

[0075] the adjustment margin L2 of the required belt tension is obtained by the following formula,

[0076] L2 = α × L / 100.

[0077] Based on the above, when setting the value that makes R1 = R2 to L1,

[0078] as long as the second long hole is designed in such a way that L2 + L3 < L1 holds, it is possible to prevent the belt from coming off the pulley.

[0079] According to the present embodiment described above, the following effects are achieved.

[0080] The belt drive device 1 of the present embodiment includes: a first pulley 10 and a second pulley 20, which are arranged at a specified distance apart and rotatably on the arm main body 30; a belt 40 wound around the first pulley 10 and the second pulley 20; a wrist bending part 106 that rotates by the rotation of the second pulley 20; and an adjustment mechanism 50 provided on the first pulley 10 to adjust the axial distance L between the first pulley 10 and the second pulley 20. The adjustment mechanism 50 includes: a support member 52 that supports the first pulley 10 rotatably; a first long hole 61 provided in the arm main body 30, the length direction of the first long hole 61 being along the axial direction F connecting between the rotation axis of the first pulley and the rotation axis of the second pulley; a first bolt 71, the rod portion 71a of which passes through the first long hole 61 to fasten the support member 52 to the arm main body 30; a second long hole 62 provided in the arm main body 30, the length direction of the second long hole 62 being along the axial direction F, the second long hole 62 being shorter than the first long hole 61; and a second bolt 72, the rod portion 72a of which passes through the second long hole 62 to fasten the support member 52 to the arm main body 30. The first long hole 61 has a first length that enables the support member 52 to move toward the second pulley 20 until the axial distance L becomes at least a distance that enables the belt 40 to be wound around the first pulley 10 and the second pulley 20. The second long hole 62 has a second length that maintains the axial distance L at a distance that does not cause the belt 40 to come off from the state of being wound around the first pulley 10 and the second pulley 20.

[0081] Thus, even if both the first bolt 71 and the second bolt 72 become loose, the axial distance L between the pulleys 10, 20 can be maintained at a distance where the belt 40 does not come off by the engagement of the second bolt 72 with the front inner edge of the second long hole 62. Therefore, it is possible to prevent the belt 40 from coming off the pulleys 10, 20. As a result, the second pulley 20 remains in a state of being braked by the belt 40, and it is possible to prevent the wrist bending part 106 from rotating together with the second pulley 20 under the action of gravity. Since the second long hole 62 is shorter than the first long hole 61, compared with the case where the length of the second long hole 62 is the same as the length of the first long hole 61, it is possible to arrange holes 30d for processing, additional members 80, etc. in a dense state near the second long hole 62. Therefore, it is possible to expand the range where the thickness of the arm main body 30 is thinner, and it is possible to miniaturize the arm main body 30.

[0082] In the belt drive device 1 of the present embodiment, the adjustment mechanism 50 further includes: an annular first sealing member 81 that surrounds the first long hole 61; and an annular second sealing member 82 that surrounds the second long hole 62. The first sealing member 81 and the second sealing member 82 are respectively sandwiched between the arm main body 30 and the support member 52.

[0083] Thus, it is possible to prevent foreign matter from entering the housing portion 31 side or the drive portion 19 side through the respective elongated holes 61 and 62. In particular, since the length of the second sealing member 82 is short, the second sealing member 82 can be made smaller than the first sealing member 81.

[0084] In the belt drive device 1 of the present embodiment, the adjustment mechanism 50 includes a plurality of first elongated holes 61, and the plurality of first elongated holes 61 are parallel to each other and extend in a straight line.

[0085] Thus, the first pulley 10 smoothly moves in the front-rear direction along the plurality of first elongated holes 61, and it is easy to adjust the axial distance L.

[0086] In the present embodiment, the second elongated hole 62 can be completely covered by the seating surface of the head of the second bolt 72.

[0087] Thus, compared with the first bolt 71 passing through the first elongated hole 61, the area where the second bolt 72 presses against the seating surface of the arm body 30 during fastening can be made larger, and the fixing strength can be increased.

[0088] The present disclosure is not limited to the above-described embodiment, and can be appropriately changed.

[0089] For example, in the above-described embodiment, the first elongated hole 61 and the second elongated hole 62 are provided in the arm body 30, but it is not limited thereto. The elongated holes 61 and 62 can be provided in at least one of the arm body 30 and the support member 52. That is, the elongated holes 61 and 62 can be provided in the support member 52, or can be provided in both the support member 52 and the arm body 30.

[0090] A bolt is used as the fastening member, but other fastening members such as rivets can be used instead of the bolt.

[0091] Each of the pulleys 10 and 20 and the belt 40 is a toothed timing pulley and a timing belt, but they can also be pulleys and belts with a smooth peripheral surface.

[0092] Description of Reference Numerals

[0093] 1, belt drive device; 10, first pulley; 20, second pulley; 30, arm body (device main body); 40, belt; 50, adjustment mechanism; 52, support member; 61, first elongated hole; 62, second elongated hole; 71, first bolt (first fastening member); 71a, rod portion of the first bolt; 72, second bolt (second fastening member); 72a, rod portion of the second bolt; 81, first sealing member; 82, second sealing member; 100, multi-joint robot; 106, wrist bending portion (rotating member); F, axial direction; L, axial distance.

Claims

1. A belt drive device, comprising: A first pulley and a second pulley, which are arranged at a prescribed distance apart and rotatably disposed on the device main body; A belt wound around the first pulley and the second pulley; and An adjustment mechanism provided on the first pulley for adjusting the axial distance between the first pulley and the second pulley, wherein The adjustment mechanism includes: A support member that supports the first pulley rotatably; A first elongated hole provided in at least one of the device main body and the support member, the length direction of the first elongated hole being along the axial direction connecting the rotation axis of the first pulley and the rotation axis of the second pulley; A first fastening member, the rod portion of which penetrates through the first elongated hole to fasten the support member to the device main body; A second elongated hole provided in at least one of the device main body and the support member, the length direction of the second elongated hole being along the axial direction, the second elongated hole being shorter than the first elongated hole; And A second fastening member, the rod portion of which penetrates through the second elongated hole to fasten the support member to the device main body, The first elongated hole has a first length, and the first length enables the support member to move in the direction of the second pulley until the axial distance becomes at least a distance that enables the belt to be wound around the first pulley and the second pulley; The second elongated hole has a second length, and the second length maintains the axial distance at a distance that does not cause the belt to disengage from the state of being wound around the first pulley and the second pulley.

2. The belt drive device according to claim 1, wherein The adjustment mechanism further includes: An annular first sealing member surrounding the first elongated hole; and An annular second sealing member surrounding the second elongated hole, The first sealing member and the second sealing member are respectively sandwiched between the device main body and the support member.

3. The belt drive device according to claim 1 or 2, wherein The adjustment mechanism has a plurality of the first elongated holes, The plurality of the first elongated holes are parallel to each other and extend in a straight line.

4. The belt drive device according to any one of claims 1 to 3, wherein The first pulley and the second pulley are synchronous pulleys, The belt is a synchronous belt meshing with the first pulley and the second pulley.

5. The belt drive device according to any one of claims 1 to 4, wherein The device main body includes the arm main body of a multi-joint robot, and the second pulley rotates a rotating member of the multi-joint robot.

6. The belt drive device according to any one of claims 1 to 5, wherein The second fastening member is a bolt, and the second elongated hole can be completely covered by the seating surface of the head of the bolt.

Images