JP4816521B2 - Belt transmission device and robot equipped with the same - Google Patents

Description

  The present invention relates to a belt transmission device that uses a belt such as a steel belt to transmit rotation of one rotating shaft to the other rotating shaft, and is suitable for driving an arm of, for example, a horizontal articulated robot.

In a general belt transmission device, the belt tension can be adjusted by (1) adjusting the tension of the belt provided between the pulley A and the pulley B by adjusting the distance between the pulleys A and B. (2) a method of adjusting the tension of the belt by pressing the idler pulley against the belt wound between the pulley A and the pulley B, and the like.
When used in a place such as an arm of a horizontal articulated robot, it is structurally difficult to change the inter-axis distance as in the method (1), so generally the method (2) is taken. ing.

  FIG. 5 shows a plan view of a conventional horizontal articulated robot. The horizontal articulated robot 1 has one end of a first arm 3 rotatably attached to the drive unit 2 and one end of a second arm 4 rotatably attached to the other end of the first arm 3. A hand portion 5 for placing a workpiece on the end is rotatably attached. In this robot, when the first arm 3 is rotated, the second arm 4 is rotated in the opposite direction, the hand unit 5 is rotated in the opposite direction to the second arm 4, and the tip of the hand unit 5 is linearly moved. The workpiece is then transported.

FIG. 6 is a longitudinal sectional view of the arm portion of the conventional horizontal articulated robot. This robot includes a hollow first rotation input shaft 104 and a second rotation input shaft 105 disposed concentrically inside the first rotation input shaft 104. The first rotation input shaft The first arm 3 is fixed to the end of 104, and a driving pulley 201 is provided to the end of the second rotation input shaft 105. The second rotation input shaft 105 is disposed on one end side of the first arm 3 and is rotatably attached to the first arm 3. On the other end side of the first arm 3, connecting shafts 106A and 106B protrude and are fixed inside the second arm 4, and a driven pulley 202 is rotatably attached to the connecting shafts 106A and 106B. . The drive pulley 201 and the driven pulley 202 have a diameter ratio of 1: 1, and a loop-like endless type timing belt 203 is wound between the drive pulley 201 and the driven pulley 202.
One end side of the second arm 4 is fixed to the upper end of the driven pulley 202, and a driving pulley 207 is fixed to the upper end portion of the connecting shaft 106 </ b> B protruding inside the second arm 4. On the other hand, the drive pulley 207 rotates relatively. A connecting shaft 110 is fixed to the other end side of the second arm 4, and a driven pulley 208 is rotatably attached to the connecting shaft 110. The drive pulley 207 and the driven pulley 208 have a diameter ratio of 1: 2. A loop-like endless type timing belt 209 is wound between the drive pulley 207 and the driven pulley 208.
The hand portion 5 is fixed to the upper end of the driven pulley 208 so that the hand portion 5 rotates relative to the second arm 4.
Further, inside the first arm 3 and the second arm 4, idler pulleys 211, 211 ′, 212, 212 ′ are provided, respectively. The idler pulleys 211, 211 ′, 212, 212 ′ are timings. In order to adjust the belt tension, the belt is pressed against the timing belts 203 and 209, respectively.
In this structure, when the first arm 3 is rotated by rotating the first rotation input shaft 104 relative to the second rotation input shaft 105, the drive pulley 201 is relative to the first arm 3. The relative rotation of the drive pulley 201 rotates the driven pulley 202 via the timing belt 203 to rotate the second arm 4. As the second arm 4 rotates, a relative rotation occurs between the second arm 4 and the driving pulley 207, and this relative rotation rotates the driven pulley 208 via the timing belt 209 to rotate the hand unit 5. .
At this time, the diameter ratio between the driving pulley 201 and the driven pulley 202 in the first arm 3 is 1: 1, and the diameter ratio between the driving pulley 207 and the driven pulley 208 in the second arm 4 is 1: 2. Therefore, when the first rotation input shaft 104, that is, the first arm 3 is rotated in the reverse direction at the same speed with respect to the rotation of the second rotation input shaft 105, the drive pulley 201 is Since the second arm 4 rotates relative to the arm 3 by a double amount of rotation, the second arm 4 rotates by a double amount of rotation in the opposite direction to the first arm. Since the arm 4 rotates in the opposite direction by a half rotation amount, the tip of the hand portion 5 moves straight.

Next, a method for adjusting the belt tension in the conventional horizontal articulated robot as described above will be described.
FIG. 7 shows a plan view with the lid of the first arm 3 of the horizontal articulated robot described above removed. As described above, the driving pulley 201 for rotating the second arm 4 is attached to one end side of the first arm 3 so as to be rotatable with respect to the first arm 3. On the other end side of the first arm 3, a driven pulley 202 is rotatably attached to the first arm 3. Between the driving pulley 201 and the driven pulley 202, a loop-shaped endless type timing belt 203 is wound. The first arm 3 is provided with idler pulleys 211 and 211 ′. The idler pulleys 211 and 211 ′ are attached to the timing belt 203 by pressing against the timing belt 203 so as to give a predetermined tension. It is.
The idler pulleys 211 and 211 ′ are attached so that the shafts 211A and 211A ′ are fixed on the base plates 211B and 211B ′, and are rotatable with respect to the shafts 211A and 211A ′. In order to adjust the tension of the timing belt 203 with the idler pulleys 211 and 211 ′, the idler pulleys 211 and 211 to the timing belt 203 are adjusted by adjusting the fixing positions of the base plates 211B and 211B ′ with respect to the first arm 3. The pressing amount of 211 ′ is adjusted so that a predetermined tension is obtained.
Although not shown, the second arm 4 has the same configuration as that of the first arm, and the idler pulleys 212 and 212 ′ are pressed against the timing belt 209 so as to apply a predetermined tension to the timing belt 209. It is attached.

By the way, as described above, in the conventional belt transmission device, the belt tension is adjusted by using the idler pulley. Therefore, the structure is complicated and the arm is provided only for the installation of the idler pulley. There was a problem that it was not possible to realize space saving and weight reduction.
In addition, the timing belt as described above is used when the backlash between the pulley and the timing belt tooth profile or the belt material is an elastic body such as polyurethane or rubber, so that the transmission of the pulley is reversed. There was a delay, which could adversely affect the straightness of the hand.

In order to solve the above problem, the present invention is configured as follows.
In the first aspect of the present invention, the first pulley and the second pulley are arranged on each of the pair of rotating shafts, and the belt wound around the first pulley and the second pulley, In the belt transmission device that transmits one rotation of the pair of rotating shafts to the other, the belt includes a first end belt and a second end belt, and the first end belt has one end. The adjustment block is opened and attached at a predetermined winding angle above the outer periphery of the first pulley, and the other end is attached at a predetermined winding angle above the outer periphery of the second pulley. The two end belts are attached at one end below the outer periphery of the first pulley with a predetermined wrap angle, and the other end is opposite to the wrap direction of the first end belt. Below the outer periphery of the second pulley The first pulley is attached with a fixed winding angle, and a guide portion that guides the adjustment block in a tangential direction while sliding the adjustment block on a portion to which the adjustment block is fixed, and a screw near the adjustment block A tension adjustment screw having a hole, a screw part that can be inserted into the screw hole, and a taper part provided at an upper part of the screw part, and detachable with respect to the adjustment block. When the screw is screwed into the screw hole, the tapered portion comes into contact with the adjustment block, and the adjustment block is moved in the tangential direction by the guide portion, whereby the first and second end belts are moved. Both tensions are adjusted, and after adjusting the tension, the adjusting block is fixed to the first pulley, and the tension adjusting screw is connected to the adjusting block. Removed from click, it is an constructed belt drive to complete the adjustment of the tension of the belt.
According to a second aspect of the present invention, when the guide portion and the screw hole are provided in a recess provided in the upper surface of the first pulley, and the adjustment block is fixed, the first pulley The belt transmission device according to claim 1, wherein the belt transmission device is configured to be embedded in the belt.
The invention according to claim 3 is the belt transmission device according to claim 1, wherein the belt is a metal steel belt.
According to a fourth aspect of the present invention, there is provided a horizontal articulated robot comprising the horizontal articulated type arm in which a plurality of arms are connected to each other and the belt transmission device according to any one of the first to third aspects. Is.

According to the first aspect of the present invention, the tension of the belt can be adjusted with a simple configuration using a tension adjusting screw without installing an idler pulley as in the prior art, thereby saving space and weight. Can be planned. In addition, since the tension adjusting screw is configured to be removable, the tension adjusting portion does not require extra space. Further, according to the present invention, since both ends of the belt are directly attached to the pulley, there is no backlash like a timing belt, and when the rotation direction of the pulley is reversed, transmission delay due to backlash does not occur, When applied to a joint robot, it does not adversely affect the straightness of the hand.
According to the invention described in claim 2, since the adjustment block is fixed so as to be embedded in the first pulley, there is no extra protrusion from the tension adjustment unit, and when applied to a horizontal articulated robot, There is no need for extra space. In addition, a recess is provided on the top surface of the pulley so that the position of the adjustment block can be adjusted, so it can be applied to horizontally extending arms such as a horizontal articulated robot, and the arm can be easily opened from the top. The tension can be adjusted.
Further, according to the invention of claim 3, since a metal steel belt is used, unlike the case of materials such as polyurethane and rubber, the elasticity of the belt can be almost neglected, and when the rotation direction of the pulley is reversed, There is no transmission delay, and when applied to a horizontal articulated robot, the straightness of the hand is not adversely affected.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The belt transmission device of this embodiment is applied to a belt transmission device that drives an arm of a horizontal articulated robot. The overall structure of the horizontal articulated robot is the same as that of the conventional example shown in FIG. 5, but the structure of the belt transmission device arranged inside the arm is different as described below.

FIG. 1 is a longitudinal sectional view of an arm portion of a horizontal articulated robot showing an embodiment of the present invention. This robot includes a hollow first rotation input shaft 104 and a second rotation input shaft 105 disposed concentrically inside the first rotation input shaft 104. The first rotation input shaft The first arm 3 is fixed to the end of 104, and the driving pulley 101 is provided to the end of the second rotation input shaft 105. The second rotation input shaft 105 is disposed on one end side of the first arm 3 and is rotatably attached to the first arm 3. On the other end side of the first arm 3, connecting shafts 106A and 106B protrude and are fixed inside the second arm 4, and a driven pulley 102 is rotatably attached to the connecting shafts 106A and 106B. . The diameter ratio between the driving pulley 101 and the driven pulley 102 is set to be 1: 1.
Further, one end of the second arm 4 is fixed to the upper end of the driven pulley 102, and a driving pulley 107 is fixed to the upper end portion of the connecting shaft 106 </ b> B protruding inside the second arm 4. On the other hand, the drive pulley 107 rotates relatively. A connecting shaft 110 is fixed to the other end side of the second arm 4, and a driven pulley 108 is rotatably attached to the connecting shaft 110. The diameter ratio between the driving pulley 107 and the driven pulley 108 is set to be 1: 2.
The hand portion 5 is fixed to the upper end of the driven pulley 108, and the hand portion 5 rotates relative to the second arm 4.
In addition, between the drive pulley 101 and the driven pulley 102 in the 1st arm 3, it is not a loop-shaped endless type belt, but each of the 1st and 2nd of linear and fixed length is respectively. Steel belts 103A and 103B are installed.
Further, between the driving pulley 107 and the driven pulley 108 in the second arm 4, as in the case of the first arm 3, each is not a loop-like endless belt, but is linear and has a certain length. First and second steel belts 109A and 109B are installed.

2 is a diagram showing a schematic configuration of the pulley and the belt in FIG. 1, FIG. 2 (a) is a view taken along the line aa of the first arm 3 portion of FIG. 1, and FIG. 2 (b) is a diagram of FIG. It is a bb arrow line view of 1 arm 3 part. As shown in FIG. 2, in this embodiment, the first belt 103A has one end attached to the upper periphery of the drive pulley 101 via the adjustment block 111 with a predetermined winding angle, and the other end fixed to the fixing portion. 114 is attached to the upper side of the outer periphery of the driven pulley 102 with a predetermined winding angle. The tension adjustment unit 120 including the adjustment block 111 will be described later. One end of the second belt 103B is attached to the lower side of the outer periphery of the drive pulley 101 via a fixed portion 115 with a predetermined wrap angle, and the other end is wound around the first belt 103A via a fixed portion 116. It is attached to the lower side of the outer periphery of the driven pulley 102 with a predetermined wrap angle opposite to the hooking direction.
Although not shown, the first arm 109 </ b> A also has a predetermined winding angle on the upper side of the outer periphery of the driving pulley 107 via the adjustment block 112, as in the case of the first arm 3. And the other end is attached to the upper side of the outer periphery of the driven pulley 108 with a predetermined winding angle via a fixed portion. One end of the second belt 109B is attached to the lower side of the outer periphery of the drive pulley 107 via a fixed portion with a predetermined winding angle, and the other end is wound around the first belt 109A via the fixed portion. On the contrary, it is attached to the lower side of the outer periphery of the driven pulley 108 with a predetermined winding angle.
In the fixing portions 114, 115, and 116, holes are provided in each pulley. On the other hand, each belt is completely fixed to the hole of each pulley with a press-fit pin or the like through the hole provided in each belt.
As described above, in the belt transmission device of the present invention, the two belts having both ends are mounted on the two pulleys with different vertical heights and opposite winding directions. One end of the upper belt is fixed to one pulley via an adjustment block, and the other end of the upper belt is attached to the other pulley via a fixing portion. In addition, both ends of the lower belt are only attached to the respective pulleys via fixing portions. Details of the tension adjustment unit including the adjustment block will be described later.

In the above structure, when the first arm 3 is rotated by rotating the first rotation input shaft 104 relative to the second rotation input shaft 105, the drive pulley 101 is moved relative to the first arm 3. The relative rotation of the drive pulley 101 causes the second arm 4 to rotate by rotating the driven pulley 102 via the steel belts 103A and 103B. As the second arm 4 rotates, a relative rotation occurs between the second arm 4 and the drive pulley 107. This relative rotation causes the hand pulley 5 to rotate by rotating the driven pulley 108 via the steel belts 109A and 109B. Rotate.
At this time, the diameter ratio between the driving pulley 101 and the driven pulley 102 in the first arm 3 is 1: 1, and the diameter ratio between the driving pulley 107 and the driven pulley 108 in the second arm 4 is 1: 2. Therefore, when the first rotation input shaft 104, that is, the first arm 3 is rotated in the reverse direction at the same speed with respect to the rotation of the second rotation input shaft 105, the drive pulley 101 is Since the second arm 4 rotates relative to the arm 3 by a double amount of rotation, the second arm 4 rotates by a double amount of rotation in the opposite direction relative to the first arm 3, and the hand unit 5 Since the second arm 4 rotates in the opposite direction by a half of the amount of rotation, the tip of the hand unit 5 moves straight.

Next, the tension adjusting unit 120 in the belt transmission apparatus described above will be described in detail, and a belt tension adjusting method will be described.
FIG. 3 is a plan view of the main part of the drive pulley when the belt tension is adjusted. 4 is a cross-sectional view taken along the line cc in FIG.
3 and 4, reference numeral 101 denotes a drive pulley, and a recess 101 </ b> B is formed at an attachment location of the adjustment block 111. The recess 101B is a part formed on a part of the upper surface of the drive pulley 101 and is formed one step lower than the upper surface of the pulley. The concave portion 101B is substantially T-shaped when viewed from above, and one end of the T-shape opens to the outer peripheral portion of the pulley through an opening 101C. Further, a part of the T-shape is formed so as to be in a direction substantially parallel to the tangential direction in the opening 101C, like the guide portion 101D.
The shape of the adjustment block 111 is substantially L-shaped along a part of the T-shape of the recess 101B when viewed from above. Part of the L-shape of the adjustment block 111 can be slid by being fitted into the guide portion 101D of the recess 101B. At this time, one end of the L-shape of the adjustment block 111 is formed so as to be substantially in the same position as the outer peripheral surface of the pulley in the opening 101C. A fixing portion 111C is provided at one end, and the first belt 103A is fixed. Specifically, the belt is completely fixed to the block with a press-fit pin or the like through a hole formed in the first belt 103A with respect to a hole (not shown) of the adjustment block 111. The opening 101C has a gap that does not interfere with the opening 101C and the guide block 111 even if the adjustment block 111 slides along the guide 101D.
The adjustment block 111 is provided with mounting screws 111A and 111B for fixing the adjustment block 111 to the drive pulley 101 in the vicinity of a portion that slides along the guide portion 101D. Needless to say, a screw hole (not shown) into which the screws 111A and 111B are inserted is formed in the recess 101B. A screw hole 101A is also formed in the recess 101B near the adjustment block 111.

  113 is a tension adjustment jig prepared separately from the drive pulley 101 and the adjustment block 111, and has a screw portion 113A at the tip and a taper portion 113B in the middle. The screw portion 113A of the tension adjusting jig 113 is formed so as to be inserted into the screw hole 101A. At this time, the taper portion 113B comes into contact with a part of the adjustment block 111. The upper end portion of the tension adjusting jig 113 is formed so that the screw portion 113A can be rotated with a desired tool.

In the above configuration, a belt tension adjusting method will be described.
When the screw portion 113A of the tension adjustment jig 113 is screwed into the screw hole 101A of the drive pulley with the mounting screws 111A and 111B of the adjustment block 111 loosened, the tension adjustment jig 113 moves downward in the axial direction. At the same time, the taper portion 113B of the tension adjustment jig pushes the adjustment block 111 in the direction of the outer peripheral tangent of the drive pulley 101 by the wedge action. Therefore, the adjustment block 111 pulls the first belt 103A, and the tension of the first belt 103A increases. On the other hand, since the driving pulley 101 and the driven pulley 102 are connected by the second belt 103B, when the first belt 103A is pulled, the driven pulley 102 tries to rotate, but the second belt 103B is moved to it. Therefore, the tension of the second belt 103B is also increased. In this manner, the tension of the steel belts 103A and 103B can be adjusted by adjusting the screwing amount of the tension adjusting jig 113. When the tension is adjusted to a predetermined level, the adjustment screws 111A and 111B of the adjustment block 111 are tightened to fix the attachment position of the adjustment block 111, and the tension adjustment jig 113 is removed to complete the tension adjustment.

According to the present embodiment, as described above, the tension adjustment jig can be removed after the tension adjustment, so there is no complicated mechanism such as an idler pulley in the arm, and the space and weight of the arm are reduced. Can be achieved. Further, since the adjustment block is embedded in the recess and there are few portions protruding from the pulley, further space saving of the arm can be achieved.
In addition, since both ends of the belt are directly attached to the pulley, there is no backlash like a timing belt, and when the rotation direction of the pulley is reversed, transmission delay due to backlash does not occur, and it was applied to a horizontal articulated robot. In this case, the straightness of the hand is not adversely affected.
In addition, when a metal steel belt is used as in this embodiment, the elasticity of the belt can be neglected unlike the case of materials such as polyurethane and rubber, so when the rotation direction of the pulley is reversed, transmission delay is caused. When this is applied to a horizontal articulated robot, the straightness of the hand is not adversely affected.
In the above-described embodiment, the case where the adjustment block is attached to the drive pulley side and the tension adjustment is performed is shown, but the structure may be such that the adjustment block is attached to the driven pulley side.

1 is a longitudinal sectional view of a horizontal articulated robot having a belt transmission device according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows the belt transmission apparatus of this invention, (a) is an aa arrow directional view of the 1st arm 3 part of FIG. 1, (b) is bb of the 1st arm 3 part of FIG. It is an arrow view. The principal part top view at the time of tension adjustment in the belt transmission of this invention. It is cc sectional drawing of FIG. It is a top view of the conventional horizontal articulated robot. It is a longitudinal cross-sectional view of a horizontal articulated robot having a conventional belt transmission device. It is an internal top view of the 1st arm in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Horizontal articulated robot with belt transmission device 2 Drive part 3 1st arm 4 2nd arm 5 Hand 101 Drive pulley 101A in 1st arm Screw hole 101B Recessed part 101C Opening part 101D Guide part 102 Followed in 1st arm Pulley 103A First steel belt 103B in the first arm Second steel belt 104 in the first arm 104 First rotation input shaft 105 Second rotation input shaft 106A, 106B Connecting shaft 107 fixed to the first arm 107 Drive pulley 108 in two arms Driven pulley 109A in second arm First steel belt 109B in second arm Second steel belt 110 in second arm Connection shaft 111 fixed to second arm 111 of first arm Adjustment block 111A, 111B First arm adjustment block mounting screw 111C fixing portion 112 first Two-arm adjustment block 112A, 112B Second arm adjustment block mounting screw 113 Tension adjustment jig 113A Tension adjustment jig screw part 113B Tension adjustment jig taper part 114 First steel belt in the first arm Fixing part 115 Fixing part 116 of the second steel belt in the first arm Fixing part 120 of the second steel belt in the first arm Tension adjusting part 201 Driving pulley 202 in the first arm Driven pulley in the first arm 203 Timing belt 207 in the first arm Drive pulley 208 in the second arm Driven pulley 209 in the second arm Timing belts 211 and 211 ′ in the second arm Idler pulleys 211A and 211A ′ in the first arm Inside idler pulley shaft 211B, 211B 'in first arm The base plate 212, 212 of the idler pulleys' idler pulleys 212A in the second arm, 212A 'axis 212B of the idler pulley in the second arm, 212B' base plate of the idler pulley in the second arm

Claims (4)

A first pulley and a second pulley are disposed on each of the pair of rotating shafts, and one of the pair of rotating shafts is rotated by a belt wound around the first pulley and the second pulley. In the belt transmission device that transmits
The belt is composed of a first end belt and a second end belt, and one end of the first end belt is wound around a predetermined block above the outer periphery of the first pulley through an adjustment block. The second end belt is attached at a predetermined angle above the outer periphery of the second pulley, and the other end is attached at a predetermined angle below the outer periphery of the first pulley. Attached with a predetermined wrap angle, and attached with a predetermined wrap angle below the outer periphery of the second pulley so that the other end is opposite to the wrap direction of the first end belt,
The first pulley has a portion where the adjustment block is fixed,
A guide portion for guiding the adjustment block in a tangential direction while sliding the adjustment block;
A screw hole near the adjustment block;
A tension adjustment screw having a screw part that can be inserted into the screw hole and a taper part provided at an upper part of the screw part, and removable with respect to the adjustment block;
When the tension adjusting screw is screwed into the screw hole, the tapered portion comes into contact with the adjusting block, and the adjusting block moves in the tangential direction by the guide portion, whereby the first and second existence screws are provided. Both tensions of the end belt are adjusted, and after adjusting the tension, the adjusting block is fixed to the first pulley, and the tension adjusting screw is removed from the adjusting block to complete the adjustment of the belt tension. A belt transmission device characterized in that the belt transmission device is configured.   The guide portion and the screw hole are provided in a recess provided on the upper surface of the first pulley, and are configured to be embedded in the first pulley when the adjustment block is fixed. The belt transmission device according to claim 1, wherein   The belt transmission device according to claim 1, wherein the belt is a metal steel belt.   A horizontal articulated robot comprising the belt transmission device according to any one of claims 1 to 3 in the horizontal articulated arm in which a plurality of arms are connected to each other.

Images