Robot

Abstract

To provide a robot that is configured so that heat of a speed reducer can be released efficiently.SOLUTION: The robot is provided with a first arm, a second arm, and a joint part that connects the first arm to the second arm so that the arms can rotate relatively around a rotary shaft and separate from each other in a direction of the rotary shaft. The joint part has: a motor that outputs rotation force; a speed reducer having a portion positioned between the first arm and the second arm, which reduces rotation speed of the motor; and a heat releasing member that covers the portion positioned between the first arm and the second arm of the speed reducer to release heat of the speed reducer.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a robot. [Background technology]

[0002] There is known a robot that has a robot arm with multiple arms and joints that rotatably connect adjacent arms, and that drives the robot arms to assume a desired posture to perform work on a workpiece. The robot arm has multiple joints, and each joint is equipped with a joint mechanism as a drive unit for rotating the arm. The joint mechanism has a motor as a drive source and a reducer that reduces the rotational speed of the motor.

[0003] In the joint mechanism of such a robot arm, heat is generated by the driving of the motor and by the operation of the reducer, which causes the temperature of the joint mechanism to rise when the robot arm is driven. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-323286 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the robot described in Patent Document 1 has poor heat dissipation capabilities in the joint mechanism, causing the temperature of the motor and reducer to rise, and in some cases exceeding the appropriate operating temperature or allowable temperature, and this condition can continue for a long time. Conventionally, no measures have been taken to dissipate heat from the joint mechanism, particularly the reducer. [Means for solving the problem]

[0006] A robot of the present invention includes a first arm, a second arm, and a joint unit that connects the first arm and the second arm to be relatively rotatable about a rotation axis and spaced apart from each other in the direction of the rotation axis, The joint portion is a motor that outputs rotational force; a reducer having a portion located between the first arm and the second arm and configured to reduce the rotational speed of the motor; and a heat dissipation member that covers a portion of the reducer located between the first arm and the second arm and dissipates heat from the reducer.

[0007] A robot of the present invention includes a robot arm having a first arm, a second arm, and a joint portion that connects the first arm and the second arm to be rotatable relative to each other around a rotation axis and spaced apart from each other in the direction of the rotation axis, The joint portion is a motor that outputs rotational force; a reducer having a small diameter portion accommodated in the first arm and a large diameter portion having a diameter larger than that of the small diameter portion, the reducer reducing the rotation speed of the motor; The large diameter portion is located between the first arm and the second arm. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a robot system including a robot according to a first embodiment of the present invention. [Figure 2] 5 is a cross-sectional view of a second reducer provided in the robot shown in FIG. 1, taken along line AA in FIG. 4. FIG. [Figure 3] FIG. 3 is a perspective view showing the internal structure of the second reducer shown in FIG. 2. [Figure 4] 2 is a partial cross-sectional side view of a second joint portion and its periphery provided in the robot shown in FIG. 1. FIG. [Figure 5] FIG. 10 is a perspective view showing the internal structure of a second reducer included in a robot according to a second embodiment of the present invention. [Figure 6]FIG. 10 is a partial cross-sectional side view of a second joint unit and its surrounding area provided in a robot according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A robot according to the present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings.

[0010] First Embodiment Fig. 1 is a schematic configuration diagram of a robot system including a robot according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view of a second reducer included in the robot shown in Fig. 1, taken along line A-A in Fig. 4. Fig. 3 is a perspective view showing the internal structure of the second reducer shown in Fig. 2. Fig. 4 is a partial cross-sectional side view of a second joint unit and its periphery included in the robot shown in Fig. 1.

[0011] 1, 3, and 4 correspond to the vertical direction, and the upper side in Figures 1, 3, 4, 5, and 6 will also be referred to as "upper" and the lower side will also be referred to as "lower." With regard to robot arm 72, first arm 73, and second arm 74, the right side in Figure 1 will be referred to as the "base end" and the left side will be referred to as the "tip end."

[0012] Furthermore, in this specification, "vertical" refers not only to the case where the object is aligned with the vertical, but also to the case where the object is slightly tilted from the vertical, for example, within ±10°. "Horizontal" refers not only to the case where the object is aligned with the horizontal, but also to the case where the object is slightly tilted from the horizontal, for example, within ±10°. "Parallel" refers not only to the case where two objects are aligned with the horizontal, but also to the case where the object is slightly tilted from the horizontal, for example, within ±10°.

[0013] The robot system 1 shown in FIG. 1 includes a robot 7 and a control device 6 that controls the driving of each part of the robot 7.

[0014] The robot 7 in this embodiment is a scalar robot, and is used for tasks such as holding, transporting, assembling, processing, painting, and inspecting workpieces such as electronic components (hereinafter these are collectively referred to as "tasks"). However, the use of the robot 7 and the type of task are not particularly limited. Furthermore, the robot 7 may be a robot other than a scalar robot, such as a six-axis articulated robot or a dual-arm robot.

[0015] As shown in FIG. 1, the robot 7 has a base 71 and a robot arm 72 rotatably connected to the base 71.

[0016] The base 71 is installed on the floor of a work room in a factory, etc. The base 71 may be installed on a location other than the floor, such as a wall, a ceiling, a stand, or a movable stand.

[0017] The control device 6 is installed inside the base 71. However, the present invention is not limited to this configuration, and the control device 6 may be installed in a location other than the base 71.

[0018] The robot arm 72 has a first arm 73 rotatably connected to the base 71 around a first rotation axis J1, a second arm 74 rotatably connected to the first arm 73 around a second rotation axis J2, and a work head 75 rotatably connected to the second arm 74 around a third rotation axis J3 and movable in the axial direction (up and down) of the third rotation axis J3.

[0019] 1, and has a base end 73A and a tip end 73B. The base end 73A is connected to the base 71. The first arm 73 rotates around a first rotation axis J1 that is perpendicular to the base 71.

[0020] The second arm 74 has a longitudinal shape extending in the lateral direction (horizontal direction) in Figure 1, and has a base end 74A and a tip end 74B. The base end 74A of the second arm 74 is connected to the tip end 73B of the first arm 73. The second arm 74 rotates around a second rotation axis J2 that is perpendicular to the first arm 73.

[0021] FIG. 1 shows the reference posture (home position) of the robot arm 72, and in this reference posture, the longitudinal direction of the first arm 73 and the longitudinal direction of the second arm 74 are parallel to each other.

[0022] In the reference position of the robot arm 72, the first rotation axis J1, the second rotation axis J2, and the third rotation axis J3 are parallel, but even when the robot arm 72 is driven to perform a desired operation and its position is changed from the reference position, the first rotation axis J1, the second rotation axis J2, and the third rotation axis J3 remain parallel.

[0023] A work head 75 is provided on the tip 74B of the second arm 74. The work head 75 has a spline nut 751 and a ball screw nut 752 that are coaxially arranged on the tip of the second arm 74, and a spline shaft 753 that is inserted through the spline nut 751 and the ball screw nut 752. The spline shaft 753 is rotatable relative to the second arm 74 around a third rotation axis J3 that is its central axis and extends along the vertical direction, and is also movable up and down in a direction along the third rotation axis J3.

[0024] An end effector 76 is attached to the lower end of the spline shaft 753. The end effector 76 is detachable from the spline shaft 753, and an end effector suitable for the intended work is selected as appropriate.

[0025] The robot arm 72 has a first joint 2K, a second joint 3K, a third joint 4K, and a fourth joint 5K.

[0026] The first joint portion 2K rotatably connects the first arm 73 to the base 71, and has a motor unit 2 that rotates the first arm 73 relative to the base 71 around a first rotation axis J1.

[0027] The second joint portion 3K rotatably connects the second arm 74 to the first arm 73, and has a motor unit 3 that rotates the second arm 74 relative to the first arm 73 around a second rotation axis J2.

[0028] The third joint portion 4K connects the spline shaft 753 to the second arm 74 so that it can be raised and lowered along the third rotation axis J3, and has a first drive mechanism 4 that rotates the ball screw nut 752 to raise and lower the spline shaft 753 in a direction along the third rotation axis J3.

[0029] The fourth joint portion 5K connects the spline shaft 753 to the second arm 74 so that it can rotate around the third rotation axis J3, and has a second drive mechanism 5 that rotates the spline nut 751 to rotate the spline shaft 753 around the third rotation axis J3.

[0030] The motor unit 2 has a motor 21 and a power transmission mechanism 22 that uses the motor 21 as a drive source. The motor 21 generates a drive force that rotates the first arm 73 relative to the base 71.

[0031] The motor unit 3 has a motor 31 and a power transmission mechanism 32 that uses the motor 31 as a drive source. The motor 31 generates a drive force that rotates the second arm 74 relative to the first arm 73.

[0032] The first drive mechanism 4 has a motor 41 and a power transmission mechanism 42 that uses the motor 41 as a drive source. The motor 41 generates a drive force that rotates the ball screw nut 752 to raise and lower the spline shaft 753 in the direction along the third rotation axis J3.

[0033] The second drive mechanism 5 has a motor 51 and a power transmission mechanism 52 that uses the motor 51 as a drive source. The motor 51 generates a drive force that rotates the spline nut 751 to rotate the spline shaft 753 about the third rotation axis J3.

[0034] The motors 21, 31, 41 and 51 are not particularly limited, but examples thereof include servo motors such as AC servo motors and DC servo motors.

[0035] Although not shown, motors 21, 31, 41, and 51 each include a stator, a rotor that rotates inside the stator, and a case that houses these components. The stator is arranged along the inner circumference of the case and has windings, such as three-phase windings. The stator generates a magnetic field when current, for example, three-phase AC current, is passed through the windings. In motors 21, 31, 41, and 51, the current flow pattern, current flow timing, current amount, and the like, for each winding of the stator are controlled by control device 6. As a result, motors 21, 31, 41, and 51 rotate with the desired timing, direction, and speed, respectively.

[0036] The power transmission mechanism 22 has a first reducer 23A. The power transmission mechanism 32 has a second reducer 23B. The power transmission mechanism 42 has a pulley and a belt (not shown). The power transmission mechanism 52 has a pulley and a belt (not shown).

[0037] The first reducer 23A and the second reducer 23B are each a planetary gear type reducer. The first reducer 23A and the second reducer 23B have the same configuration except for differences in overall size, reduction ratio, etc., so the following description will be given representatively of the second reducer 23B.

[0038] As shown in Figures 2 and 3, the second reducer 23B has a casing 231, an internal gear 233, a sun gear 234, multiple planetary gears 235 (three in this embodiment), a carrier 236, an input shaft 237, and an output shaft 238. In Figure 3, the input shaft 237 and the output shaft 238 are illustrated thinner than they actually are to make the internal structure easier to see. This also applies to Figure 5, which will be described later. The second reducer 23B may have an elastic support member on the outside of the internal gear 233. The elastic support member allows radial deformation of the internal gear 233 due to the action of stress, and has strength sufficient to prevent phase shift in the circumferential direction relative to the casing 231.

[0039] As shown in FIG. 2, the casing 231 is cylindrical and has the function of protecting each component therein.

[0040] 3, the internal gear 233 has a ring or cylindrical shape with the axis O1 as its central axis, and has internal teeth 233A on its inner periphery. The internal teeth 233A mesh with the teeth 235A of each planetary gear 235.

[0041] The sun gear 234 has teeth 234A on its outer periphery and is disposed inside the internal gear 233 and concentrically therewith. The sun gear 234 is connected to an input shaft 237 and rotates around an axis O1. The input shaft 237 is connected to an output shaft 311 of the motor 31, for example, via a bearing (not shown), as shown in FIG. 4. The motor 31 is fixed directly or indirectly to an arm base 741 of the second arm 74.

[0042] The three planetary gears 235 are arranged at equal angular intervals from one another on the outer circumferential side of the sun gear 234 and on the inner circumferential side of the internal gear 233. Each planetary gear 235 has teeth 235A on its outer periphery, which mesh with teeth 234A of the sun gear 234 and internal teeth 233A of the internal gear 233. The three planetary gears 235 each have the same diameter and the same number of teeth 235A.

[0043] As shown in FIGS. 2 and 3, the gear train of the sun gear 234 and the three planetary gears 235 is provided in a single row on the same plane, that is, on a predetermined cross section of the second reducer 23B.

[0044] Furthermore, there are no particular limitations on the types, shapes, etc. of the internal gear 233, sun gear 234, and planetary gears 235, and in the illustrated configuration, they are all spur gears. However, in the present invention, it is preferable that the internal gear 233, sun gear 234, and planetary gears 235 are each helical gears.

[0045] Carrier 236 supports planetary gear 235 rotatably around axis O2, which is the central axis of planetary gear 235. In the illustrated configuration, carrier 236 has a so-called star shape, in which three rod-shaped members arranged at 120° intervals are connected at their ends on the axis O1 side. However, the configuration is not limited to this, and carrier 236 may be formed of, for example, a frame-shaped member or a disk-shaped member.

[0046] An output shaft 238 is connected to the center of the carrier 236. The output shaft 238 is fixed to the tip end 73B of the first arm 73, for example, via a bearing (not shown).

[0047] The rotational force transmitted from the motor 31 is transmitted to the sun gear 234 via the input shaft 237, causing the sun gear 234 to rotate in a predetermined direction around the axis O1. When the sun gear 234 rotates, each planetary gear 235 rotates (spins) around the axis O2 while rotating (revolves) around the axis O1. The revolution of each planetary gear 235 around the axis O1 causes the carrier 236 to rotate around the axis O1, and the output shaft 238 to rotate around the axis O1. As a result, the rotation of the output shaft 238 is reduced by the planetary gears 235 and becomes slower than the rotation of the input shaft 237. Therefore, the rotational speed of the input shaft 237 is reduced and output from the output shaft 238. As a result, the second arm 74 can rotate relative to the first arm 73 at a reduced speed, thereby increasing the rotational torque of the second arm 74.

[0048] The rotational speed ratio of the output shaft 238 to the input shaft 237, that is, the reduction ratio of the second reducer 23B, is not particularly limited, but a preferable range thereof will be described later.

[0049] 1, the input shaft of first reducer 23A is connected to motor 21 fixed to base 71, and the output shaft of first reducer 23A is fixed to base end 73A of first arm 73. Therefore, based on the same principle as above, first arm 73 can rotate at a desired rotational speed that is reduced relative to base 71.

[0050] Alternatively, the input shaft of the first reducer 23A may be fixed to the base 71, and the output shaft of the first reducer 23A may be fixed to the base end 73A of the first arm 73.

[0051] The internal gear 233 has higher elasticity than the sun gear 234 and the planetary gears 235. However, it is sufficient that the internal gear 233 has higher elasticity than the planetary gears 235. This makes it possible to suppress backlash and further improve the positional accuracy of each part when the robot arm 72 is in operation.

[0052] "Elasticity" in this specification is determined not only by the material but also by the shape, etc., and refers to the property of an object that, when a force is applied to it, returns to its original shape when the force is released. High elasticity means that an object quickly returns to its original shape when the force is released. In other words, "elasticity" in this specification is different from properties determined by the material, such as Young's modulus.

[0053] The casing 231, the internal gear 233, the sun gear 234, the planetary gears 235, the carrier 236, the input shaft 237, and the output shaft 238 are made of, for example, a metal material or a hard resin material.

[0054] As described above, the second reducer 23B includes a ring-shaped internal gear 233, a sun gear 234 that is arranged inside the internal gear 233 and concentrically with the internal gear 233, a plurality of planetary gears 235 that mesh with both the internal gear 233 and the sun gear 234, and a carrier 236 that rotatably supports each planetary gear 235, and the internal gear 233 has higher elasticity than the planetary gears 235. This makes it possible to suppress backlash and further improve the positional accuracy of each part of the robot arm 72.

[0055] The internal gear 233 is not limited to the above configuration, and may have elasticity equivalent to that of the planetary gear 235, or may have elasticity lower than that of the planetary gear 235.

[0056] In addition, the second reducer 23B has a single gear train including the sun gear 234 and the plurality of planetary gears 235. By minimizing the number of gear trains in this way, it is possible to reduce loss during torque transmission in the second reducer 23B. Furthermore, it is possible to reduce the weight of the second reducer 23B.

[0057] Furthermore, it is preferable that the internal gear 233, sun gear 234, and planetary gears 235 are each helical gears. That is, it is preferable that the internal gear 233, sun gear 234, and planetary gears 235 are helical gears. This allows the meshing area of ​​the teeth to be larger than in spur gears, and reduces the surface pressure on the tooth surfaces, making it possible to transmit relatively high torque smoothly and efficiently.

[0058] The internal gear 233, the sun gear 234, and the planetary gears 235 are not limited to the above configuration, and may be other types of gears, such as spur gears.

[0059] The reduction ratio V1 of the first reducer 23A is preferably 1 / 100 or more and 1 / 3 or less, and more preferably 1 / 50 or more and 1 / 3 or less.

[0060] The reduction ratio V2 of the second reducer 23B is preferably 1 / 100 or more and 1 / 3 or less, and more preferably 1 / 50 or more and 1 / 3 or less.

[0061] The magnitude relationship between the reduction ratios V1 and V2 is not particularly limited, but it is preferable that V1≧V2, and more preferably that 0.85V1≧V2.

[0062] Such reduction ratios V1 and V2 can be set by appropriately selecting the number of teeth of the teeth 234A and the number of teeth of the teeth 235A.

[0063] Compared to strain wave gear reducers with the same maximum outer diameter, planetary gear reducers, i.e., first reducer 23A and second reducer 23B, have lower grease viscosity resistance and less torque loss. Therefore, when operating at the same rotational speed, using a planetary gear reducer enables agile movement while reducing power consumption. Therefore, a robot using a planetary gear reducer generates less heat.

[0064] The second arm 74 has an arm base 741 and a cover 742 that covers the upper part of the arm base 741 .

[0065] The structure of the second arm 74 will now be described. As shown in FIG. 4, the second arm 74 has an arm base 741 that forms the basic frame of the second arm 74 , and a cover 742 that is attached to the arm base 741 .

[0066] Cover 742 is formed of a housing with an open bottom end, covers the upper part of arm base 741, and has the function of protecting the internal components. Cover 742 is formed, for example, from a plate material made of a resin material and molded into a desired three-dimensional shape. This cover 742 preferably has enough elasticity to be slightly deformed when force is applied. Cover 742 may also be formed, for example, from a plate material made of a metal material such as stainless steel or aluminum and molded into a desired three-dimensional shape.

[0067] The arm base 741 is made of a rigid body that has the function of supporting each internal component mounted on the second arm 74. Examples of materials that can be used to form the arm base 741 include various metal materials, various resin materials, particularly hard resin materials, various ceramics, etc., and it may also be made of a composite material that is an arbitrary combination of these. Among these, examples of metal materials include stainless steel and aluminum.

[0068] The arm base 741 has an outer shape like a long block extending in the lateral direction (horizontal direction) in FIGS.

[0069] 4, a mounting portion 743 on which the motor 31 is mounted is provided at the base end portion 74A of the arm base 741. The mounting portion 743 is configured as a through-hole with the second rotation axis J2 as its central axis. The motor 31 is inserted into the mounting portion 743 and fixed therein.

[0070] A step 744 is provided on the inner periphery below the installation portion 743. The lower edge of the casing of the motor 31 abuts against this step 744, thereby fixing the position of the motor 31 in the up-down direction (the axial direction of the second rotation shaft J2). The output shaft 311 of the motor 31 protrudes downward from the center of the lower end surface of the casing of the motor 31.

[0071] The installation portion 743 has a reduced diameter portion 745 that is reduced in diameter below the step portion 744. The output shaft 311 of the motor 31 is located within the reduced diameter portion 745 of the installation portion 743 and rotates around the second rotation axis J2 without contacting the inner surface of the reduced diameter portion 745.

[0072] Meanwhile, a recess 731 having a circular cross section and opening toward the second arm 74 is provided at the tip 73B of the first arm 73. The output shaft 238 of the second reducer 23B is fixed to the bottom of the recess 731.

[0073] The recess 731 is large enough that its inner circumferential surface is not in contact with the casing 231 of the second reducer 23B installed in the recess 731. This allows heat to be dissipated from the second reducer 23B through a gap space between the inner circumferential surface of the recess 731 and the second reducer 23B. The depth of the recess 731 is such that a portion of the second reducer 23B (approximately the upper half in FIG. 4) protrudes upward from the recess 731.

[0074] With this configuration, the first arm 73 and the second arm 74 are connected together at a predetermined distance along the axial direction of the second rotation axis J2, and a part of the second reducer 23B is located between the first arm 73 and the second arm 74. Hereinafter, the part of the second reducer 23B that is located between the first arm 73 and the second arm 74 will be referred to as an intermediate part 230.

[0075] The second joint portion 3K has a heat dissipation member 33 that covers the intermediate portion 230 of the second reduction gear 23B and dissipates heat from the second reduction gear 23B.

[0076] 4, the heat dissipation member 33 is provided in contact with the casing 231 and has the function of dissipating heat generated by operation of the second reducer 23B. The heat generated by operation of the second reducer 23B is transferred to the heat dissipation member 33 via the casing 231 and dissipated into the air from the heat dissipation member 33. The heat dissipation member 33 is located in the space S between the first arm 73 and the second arm 74 and can come into contact with the outside air of the space S, so that the heat can be efficiently dissipated into the outside air.

[0077] As the second reducer 23B is driven, it generates heat due to friction between the gears, etc., causing the temperature to rise. By dissipating heat from the second reducer 23B via the heat dissipation member 33, it is possible to prevent an excessive temperature rise and operate the second reducer 23B within, for example, a proper operating temperature or an allowable temperature range. As a result, the second reducer 23B can be operated well and stably. Here, the "proper operating temperature" refers to a temperature range that is determined during the design of the second reducer 23B and in which the second reducer 23B operates properly. The "allowable temperature" refers to a temperature range beyond which, if exceeded, the second reducer 23B will malfunction or may malfunction.

[0078] When the second reducer 23B is operating within the appropriate operating temperature or the allowable temperature range, the viscosity of the grease (lubricant) present inside the second reducer 23B is also maintained at an appropriate level without excessively decreasing, so that the internal gear 233, the sun gear 234, and the planetary gear 235 each rotate appropriately and smoothly to transmit torque.

[0079] The heat dissipation via the heat dissipation member 33 as described above occurs even when the first arm 73 is stationary. However, when the first arm 73 is rotating around the first rotation axis J1, an airflow is generated in the space S around the heat dissipation member 33, so that heat dissipation is more efficient.

[0080] The shape and structure of the heat dissipation member 33 are not particularly limited, but in this embodiment, the heat dissipation member 33 has a first portion 331 and a second portion 332. The second portion 332 is connected to or integrated with an upper portion of the first portion 331. In other words, the first portion 331 and the second portion 332 are provided continuously.

[0081] The first portion 331 is a cylindrical portion that comes into contact with a portion of the outer periphery of the casing 231 of the second reducer 23B that corresponds to the intermediate portion 230, which is a portion located between the first arm 73 and the second arm 74. The first portion 331 is a portion that dissipates heat from the second reducer 23B via the intermediate portion 230.

[0082] The first portion 331 is not limited to a cylindrical shape, and may have a cylindrical shape with a portion missing, or a shape with a notch or slit. The first portion 331 may also be configured to cover the lower portion of the intermediate portion 230 of the second reducer 23B, that is, the portion inserted into the recess 731 of the casing 231.

[0083] The second portion 332 is a ring-shaped portion extending from the entire periphery of the edge of the opening on the upper end side of the first portion 331 toward the center of the opening. The second portion 332 is located between the arm base 741 of the second arm 74 and the upper end face (on the input shaft 237 side) of the casing 231 of the second reducer 23B, and is in contact with them. The inner diameter of the second portion 332 is approximately equal to the inner diameter of the reduced diameter portion 745, and the inner circumferential surface of the second portion 332 and the inner circumferential surface of the reduced diameter portion 745 are continuous. The input shaft 237 is inserted into the inside of the second portion 332 without contacting it.

[0084] The second portion 332 is a portion that absorbs heat from the second reducer 23B from the upper end surface of the casing 231 of the second reducer 23B and transfers the heat to the arm base 741, thereby dissipating the heat from the second reducer 23B.

[0085] The heat dissipation member 33 having the first portion 331 and the second portion 332 comes into contact with the outer surface of the second reducer 23B and dissipates heat, thereby producing a synergistic effect between the first portion 331 and the second portion 332, which have different heat dissipation locations, and allowing the second reducer 23B to dissipate heat more effectively.

[0086] Although not shown, the heat dissipation member 33 may have a heat sink such as a heat dissipation fin, thereby achieving a more excellent heat dissipation effect.

[0087] Even when the heat dissipation member 33 has a heat sink such as a heat dissipation fin, a high heat dissipation effect is obtained not only when the first arm 73 is stationary, but also when the first arm 73 is rotating around the first rotation axis J1, as heat escapes by convection.

[0088] Although there are no particular limitations on the material of the heat dissipation member 33, it is preferable to use various metallic materials, which can further improve the heat dissipation properties of the heat dissipation member 33.

[0089] In particular, it is preferable that the heat dissipation member 33 be made of a metal material with high thermal conductivity, such as aluminum or magnesium. This improves heat transfer from the second reducer 23B to the heat dissipation member 33, and allows heat generated by the second reducer 23B to be efficiently dissipated to the heat dissipation member 33.

[0090] The color of the heat dissipation member 33 is not particularly limited, but is preferably achromatic, and more preferably white or black, which have high thermal emissivity. This can further improve the heat dissipation properties of the heat dissipation member 33.

[0091] The heat dissipation member 33 may be made the above color by appropriately selecting the color of the constituent material itself, by applying paint containing dyes, pigments, etc., or by adhering a film such as a colored film or a colored transparent film.

[0092] The second reducer 23B, which is a reducer, is preferably a planetary gear type. When a planetary gear type reducer and a strain wave gear type reducer with the same maximum outer diameter are operated at the same rotational speed, the planetary gear type reducer generates less heat. Therefore, by using a planetary gear type reducer and including a heat dissipation member 33, it is possible to realize a robot 7 that is less susceptible to heat accumulation.

[0093] As described above, the robot 7 includes the first arm 73, the second arm 74, and the second joint 3K, which is a joint that connects the first arm 73 and the second arm 74 so that they are relatively rotatable about the second rotation axis J2, which is a rotation axis, and are spaced apart from each other in the direction of the second rotation axis J2. The second joint 3K includes the motor 31 that outputs a rotational force, the second reducer 23B that has an intermediate portion 230 that is located between the first arm 73 and the second arm 74 and is a reducer that reduces the rotational speed of the motor 31, and the heat dissipation member 33 that covers the intermediate portion 230 that is located between the first arm 73 and the second arm 74 of the second reducer 23B and dissipates heat from the second reducer 23B. This allows for efficient heat dissipation from the second reducer 23B. Therefore, the second reducer 23B can be operated within, for example, an appropriate operating temperature or an allowable temperature range, and the second reducer 23B can be operated satisfactorily and stably. A heat dissipation member similar to the heat dissipation member 33 may be installed in the first reducer 23A.

[0094] The heat dissipation member 33 has a first portion 331 that contacts a portion of the outer periphery of the casing 231 of the second reducer 23B that corresponds to the intermediate portion 230, which is a portion located between the first arm 73 and the second arm 74, and a second portion 332 that is located between the second arm 74 and the second reducer 23B. This allows heat from the second reducer 23B to be dissipated into the air from the intermediate portion 230, and also allows heat from the second reducer 23B to be dissipated to the second arm 74. Therefore, due to the synergistic effect of these, heat dissipation from the second reducer 23B can be performed more efficiently. The second portion 332 may be omitted.

[0095] The first portion 331 and the second portion 332 are provided continuously, which allows heat to be transferred between the first portion 331 and the second portion 332, thereby enabling more efficient heat dissipation from the second reducer 23B. The first portion 331 and the second portion 332 may be spaced apart from each other.

[0096] The robot 7 includes a base 71 to which a base end 73A of a first arm 73 is connected, an output shaft 238 of a second reducer 23B, which is a reducer, is fixed to a tip end 73B of the first arm 73, and a motor 31 is fixed to a second arm 74. This allows the first arm 73 to rotate relative to the base 71, and the second arm 74 to rotate relative to the first arm 73. This allows the movable range of the robot arm 72 to be increased.

[0097] The heat dissipation member 33 is in contact with the second arm 74. This allows the heat dissipation member 33 to dissipate heat from the second reducer 23B to the second arm 74, which has a relatively large heat capacity. This allows the heat from the second reducer 23B to be dissipated more efficiently.

[0098] The heat dissipation member 33 preferably has a heat sink, particularly a heat dissipation fin, which allows the second reducer 23B to dissipate heat more efficiently. The heat dissipation fins are not particularly limited and may be formed of a plurality of rod-shaped or plate-shaped protrusions or the like.

[0099] A fan or blower that blows air toward the second reducer 23B may also be installed. This allows for a more effective heat dissipation effect. Such a fan or blower may be installed, for example, on either the first arm 73 or the second arm 74. The fan or blower may have an air pipe such as a duct or tube as an auxiliary air-blowing member.

[0100] Second Embodiment FIG. 5 is a perspective view showing the internal structure of a second reducer included in a robot according to a second embodiment of the present invention.

[0101] A robot according to a second embodiment of the present invention will be described below with reference to Fig. 5. The following description will focus on differences from the first embodiment, and a description of similarities will be omitted. Note that in Fig. 5, the vertical length is exaggerated to make the internal structure easier to understand.

[0102] The second reducer 23B shown in Fig. 5 is provided with two gear trains each including a sun gear 234 and a plurality of planetary gears 235. That is, as shown in Fig. 5, a gear train 230A including a sun gear 234 and three planetary gears 235 is provided on a predetermined cross section of the second reducer 23B, and a gear train 230B including a sun gear 234 and three planetary gears 235 is provided on another cross section shifted a predetermined distance in the axial direction of the axis O1.

[0103] The gear trains 230A and 230B are arranged side by side along the axial direction of the axis O1. The lower side in Fig. 5 is the input side (the input shaft 237 side), and the upper side in Fig. 5 is the output side (the output shaft 238 side). The gear train 230A is arranged on the input side, and the gear train 230B is arranged on the output side.

[0104] Gear train 230A and gear train 230B share one internal gear 233. Furthermore, carrier 236 of gear train 230A is connected to sun gear 234 of gear train 230B via a shaft-shaped connecting portion 239. In other words, connecting portion 239 serves as both the output shaft of gear train 230A and the input shaft of gear train 230B. For this reason, the gear train 230A reduces the speed, and the gear train 230B also reduces the speed. As a result, in this embodiment, the reduction ratio V2 of second reducer 23B can be increased, for example, to between 1.3 and 3.5 times that of the first embodiment.

[0105] Thus, in the second reducer 23B, the gear train of the sun gear 234 and the plurality of planetary gears 235 is provided in multiple rows (two rows in this embodiment) along the direction of the axis O1 which is the central axis of the internal gear 233. This makes it possible to increase the reduction ratio V2 of the second reducer 23B with a simple structure, and to stably output a relatively high torque.

[0106] Gear train 230A and gear train 230B may be the same or different in various conditions such as the diameter of sun gear 234 and planetary gear 235, tooth thickness, number of planetary gears 235, number of teeth 234A and teeth 235A, etc. In particular, gear train 230A and gear train 230B may be the same or different in reduction ratio.

[0107] In this embodiment, the case where two gear trains are provided along the axial direction of the axis O1 has been described, but the present invention is not limited to this, and three or more gear trains may be provided.

[0108] In the present embodiment, the second reducer 23B also has an intermediate portion 230 located between the first arm 73 and the second arm 74, and the heat dissipation member 33 similar to that of the first embodiment is provided so as to cover the intermediate portion 230. This allows the heat of the second reducer 23B to be efficiently dissipated, similar to the first embodiment.

[0109] The second reducer 23B of this embodiment, which has multiple gear trains in the axial direction, has a larger reduction ratio V2 and can output higher torque than the second reducer 23B of the first embodiment, which can result in a larger amount of heat generated. Furthermore, the second reducer 23B of this embodiment has a longer axial length of the second rotation shaft J2 than the second reducer 23B of the first embodiment, thereby ensuring a sufficient axial length of the intermediate portion 230. Therefore, providing a heat dissipation member 33 in a second reducer 23B configured in this manner is preferable because it provides excellent heat dissipation. In other words, even a second reducer 23B that generates a large amount of heat can efficiently dissipate that heat. Therefore, as described in the first embodiment, the second reducer 23B can be operated within the appropriate operating temperature or allowable temperature range, allowing the second reducer 23B to operate satisfactorily and stably.

[0110] Third Embodiment FIG. 6 is a partial cross-sectional side view of a second joint unit and its periphery provided in a robot according to a third embodiment of the present invention.

[0111] Hereinafter, a robot according to the third embodiment of the present invention will be described with reference to FIG. 6. However, the following description will focus on the differences from the first and second embodiments, and a description of similar points will be omitted.

[0112] 6, second reducer 23B has a large diameter portion 230D located between first arm 73 and second arm 74, and a small diameter portion 230C having a smaller diameter than large diameter portion 230D. Large diameter portion 230D and small diameter portion 230C are arranged side by side in this order from the top to the bottom of second reducer 23B.

[0113] The large diameter portion 230D is a portion centered on the second rotation axis J2. The large diameter portion 230D has a larger diameter than the small diameter portion 230C, and is the portion of the casing 231 with the largest outer diameter. The outer diameter of the large diameter portion 230D is constant along the second rotation axis J2. However, this configuration is not limited thereto, and the large diameter portion 230D may have portions with different outer diameters.

[0114] The small diameter portion 230C is concentric with the large diameter portion 230D, i.e., is centered on the second rotation axis J2, and has a constant outer diameter along the second rotation axis J2. The small diameter portion 230C is surrounded by the inner circumferential surface of the recess 731 but is not in contact with it. The small diameter portion 230C is housed in the recess 731 of the first arm 73. In other words, when viewed from a direction perpendicular to the second rotation axis J2 and along the first arm 73, the small diameter portion 230C and the first arm 73 overlap.

[0115] The large diameter portion 230D is located between the first arm 73 and the second arm 74, and is exposed to the space S between the first arm 73 and the second arm 74. Therefore, the second reducer 23B can radiate heat to the outside air in the space S from the outer surface of the intermediate portion 230, particularly the outer peripheral surface. This radiated heat includes a large amount of heat generated by the operation of the second reducer 23B. As described above, the large diameter portion 230D has a larger outer diameter than the other portions of the casing 231, and therefore the area of ​​the outer peripheral surface of the large diameter portion 230D is also large. Therefore, the efficiency of heat radiation from the large diameter portion 230D is high.

[0116] In the second embodiment, the second reducer 23B is configured such that the outer surface of the large diameter portion 230D, which has a large outer diameter, is exposed to the space S between the first arm 73 and the second arm 74, and therefore heat can be efficiently dissipated from the large diameter portion 230D to the space S between the first arm 73 and the second arm 74. Therefore, for example, the second reducer 23B can be operated within an appropriate operating temperature or an allowable temperature range, and the second reducer 23B can be operated well and stably.

[0117] As described above, the robot 7 includes a robot arm 72 having a first arm 73, a second arm 74, and a second joint 3K that connects the first arm 73 and the second arm 74 so that they can rotate relatively around a second rotation axis J2 and are spaced apart from each other in the direction of the second rotation axis J2. The second joint 3K includes a motor 31 that outputs rotational force, a second reducer 23B that has a small-diameter portion 230C housed in the first arm 73 and a large-diameter portion 230D that is larger in diameter than the small-diameter portion 230C and that reduces the rotational speed of the motor 31, and the large-diameter portion 230D is located between the first arm 73 and the second arm 74. This allows efficient heat dissipation from the second reducer 23B. Therefore, the second reducer 23B can be operated, for example, within an appropriate operating temperature or an allowable temperature range, allowing the second reducer 23B to operate satisfactorily and stably.

[0118] In this embodiment, the second reducer 23B may have the same configuration as that of the second embodiment.

[0119] The robot 7 may also employ the configuration of this embodiment for the first reducer 23A. The first reducer 23A of the robot 7 may have any of the structures of the first, second and third embodiments.

[0120] While the robot of the present invention has been described above based on the illustrated embodiments, the present invention is not limited to these, and the configuration of each part can be replaced with any configuration having a similar function. In addition, any other components may be added. [Explanation of symbols]

[0121] 1...robot system, 2...motor unit, 2K...first joint portion, 3...motor unit, 3K...second joint portion, 4...first drive mechanism, 4K...third joint portion, 5...second drive mechanism, 5K...fourth joint portion, 6...control device, 7...robot, 21...motor, 22...power transmission mechanism, 23A...first reducer, 23B...second reducer, 31...motor, 32...power transmission mechanism, 3...heat dissipation member, 41...motor, 42...power transmission mechanism, 51...motor, 52...power transmission mechanism, 71...base, 72...robot arm, 73...first arm, 73A...base end portion, 73B...tip portion, 74...second arm, 74A...base end portion, 74B...tip portion, 75...working head, 76...end effector, 2 30...intermediate portion, 230A...gear train, 230B...gear train, 230C...small diameter portion, 230D...large diameter portion, 231...casing, 233...internal gear, 233A...internal teeth, 234...sun gear, 234A...teeth, 235...planetary gear, 235A...teeth, 236...carrier, 237...input shaft, 238...output shaft, 239...connection portion, 311...output shaft, 331...first portion, 332...second portion, 731...recess, 741...arm base, 742...cover, 743...mounting portion, 744...step portion, 745...reduced diameter portion, 751...spline nut, 752...ball screw nut, 753...spline shaft, J1...first rotating shaft, J2...second rotating shaft, J3...third rotating shaft, O1...shaft, O2...shaft, S...space

Claims

1. a first arm, a second arm, and a joint portion that connects the first arm and the second arm so that they can rotate relatively around a rotation axis and are spaced apart from each other in the direction of the rotation axis, The joint portion is a motor that outputs rotational force; a reducer having a portion located between the first arm and the second arm, the reducer reducing the rotational speed of the motor; a heat dissipation member that covers a portion of the reducer that is located between the first arm and the second arm and dissipates heat from the reducer.

2. 2. The robot according to claim 1, wherein the heat dissipation member has a first portion that contacts a portion of the outer periphery of the casing of the reducer that corresponds to a portion that is located between the first arm and the second arm, and a second portion that is located between the second arm and the reducer.

3. The robot according to claim 2 , wherein the first portion and the second portion are provided contiguously.

4. a base to which a base end of the first arm is connected, an output shaft of the reducer is fixed to a tip end of the first arm; The robot according to claim 1 , wherein the motor is fixed to the second arm.

5. The robot according to claim 4 , wherein the heat dissipation member is in contact with the second arm.

6. 4. The robot according to claim 1, wherein the heat dissipation member has heat dissipation fins.

7. 4. The robot according to claim 1, wherein the heat dissipation member is achromatic.

8. 4. The robot according to claim 1, wherein the heat dissipation member is made of a metal material containing aluminum or magnesium.

9. 4. The robot according to claim 1, wherein the reducer is a planetary gear type.

10. a robot arm including a first arm, a second arm, and a joint portion that connects the first arm and the second arm to be relatively rotatable about a rotation axis and spaced apart from each other in the direction of the rotation axis, The joint portion is a motor that outputs rotational force; a reducer having a small diameter portion accommodated in the first arm and a large diameter portion having a diameter larger than that of the small diameter portion, the reducer reducing the rotation speed of the motor; The robot is characterized in that the large diameter portion is located between the first arm and the second arm.

Images