JP6765249B2 - Industrial robot - Google Patents

Description

The present invention relates to an industrial robot including at least a base, a link mechanism rotatably pivoted to the base, and an arm rotatably pivoted to the link mechanism.

Conventionally, industrial robots having articulated joints have been used for welding and transporting members. The industrial robot is provided with a link mechanism pivotally attached to a base, and an arm corresponding to an arm portion of the robot is rotatably pivotally attached to the link mechanism.

As such an industrial robot, for example, Patent Document 1 proposes a base installed on an installation surface and an industrial robot having a link mechanism pivotally attached to the base. This link mechanism has one end rotatably pivotally attached to the base and rotatably pivotally attached to the first lower arm and the second lower arm and the other ends of the first lower arm and the second lower arm. It has a base.

This industrial robot further includes an upper arm portion rotatably pivotally attached to the upper base of the link mechanism, and a first rotation shaft in which the base and the first lower arm portion rotate relative to each other. The second rotating shaft, on which the base and the second lower arm rotate relative to each other, is at the same height from the installation surface.

JP-A-3-202288

However, according to the views of the inventors, in the industrial robot shown in Patent Document 1, the movement range of the tip of the upper arm portion (arm) rotatably pivotally attached to the upper base of the link mechanism is not sufficient. There was something.

In this case, by increasing the length of each arm of the link mechanism, the movable range of the link mechanism is increased, and the moving range of the tip of the upper arm portion (arm) pivotally attached to the link mechanism with respect to the base. Can be expanded. However, if such measures are taken, the industrial robot itself will become large.

The present invention has been made in view of these points, and an object of the present invention is to move the tip of an arm rotatably pivotally attached to a link mechanism to a large extent without increasing the size of the device. The purpose is to provide an industrial robot that can be made to operate.

As a result of diligent studies, the inventors focused on the rotation axes of the two arms of the link mechanism pivotally attached to the industrial robot. Specifically, by setting the positional relationship between the rotation axes of these two arms that rotate with respect to the base to different positions (different heights) with respect to the installation surface, the range of movement of the link mechanism with respect to the base However, I got a new finding that it will change significantly.

The present invention is based on a new finding of the inventors, and the industrial robot according to the present invention has a base mounted on an installation surface and a base whose one end is rotatably pivotally attached to the base. A link mechanism having a first arm and a second arm, a third arm rotatably pivotally attached to the other end of the first arm and the second arm, and the link mechanism on the first arm side. The second arm and the base are provided with a fourth arm rotatably pivoted to the base, rather than a first rotation axis in which the first arm and the base rotate relative to each other. The second rotating shaft, in which the table rotates relatively, is characterized in that it is located at a higher position than the installation surface.

According to the present invention, the first arm and the second arm can be rotated around the base so that the second rotating shaft is higher than the first rotating shaft from the installation surface. It is pivoted. Therefore, when the link mechanism is moved, the movable range of the link mechanism toward the first arm side can be expanded as compared with the one having the first and second rotation axes at the same height with respect to the installation surface. .. As a result, the tip of the fourth arm rotatably pivotally attached to the link mechanism can be largely moved on the first arm side without increasing the size of the device.

Here, as long as the first rotation axis and the second rotation axis satisfy the above-mentioned positional relationship, the rotation axes of the third arm with respect to the first arm and the second arm of the link mechanism are not particularly limited. .. However, in a more preferred embodiment, the first arm and the third arm rotate in a posture in which the first arm and the second arm stand up along a direction orthogonal to the installation surface. The fourth rotating shaft on which the second arm and the third arm rotate is located higher than the rotating shaft on the installation surface.

According to this aspect, the third arm can be rotated to the first arm and the second arm so that the fourth rotation axis is higher than the third rotation axis from the installation surface. Since it is pivotally attached to, the range in which the first arm can move can be further expanded. As a result, on the first arm side, the tip of the fourth arm rotatably pivotally attached to the link mechanism can be moved more greatly.

In a more preferred embodiment, the distance from the first rotation axis to the third rotation axis is equal to the distance from the second rotation axis to the fourth rotation axis. As a result, the link mechanism including the first arm, the second arm, and the third arm can be made into a parallel link mechanism. As a result, the pivotal range of the first arm can be further expanded, and the tip of the fourth arm can be moved even more.

Here, the position where the fourth arm is arranged is not particularly limited as long as it is rotatably pivotally attached to the link mechanism on the other end side of the first arm. However, in a more preferred embodiment, at the other end of the first arm, the third arm is arranged on one side of the first arm, and the fourth arm is arranged on the other side of the first arm. ..

According to this aspect, since the third arm and the fourth arm are arranged at the positions sandwiching the first arm, even if the fourth arm pivots with respect to the link mechanism as the link mechanism moves. , The third arm and the fourth arm are less likely to interfere mechanically. As a result, it is not necessary to limit the movable range of the link mechanism due to the pivotal movement of the fourth arm with respect to the link mechanism.

According to the present invention, the arm rotatably pivotally attached to the link mechanism can be moved more greatly to the tip end side without increasing the size of the device.

It is a side view which looked at the industrial robot which concerns on embodiment of this invention from one side. It is a side view which looked at the industrial robot shown in FIG. 1 from the other side. It is a rear view of the industrial robot shown in FIG. It is a front view of the industrial robot shown in FIG. It is a perspective view which looked at the industrial robot shown in FIG. 1 from one side. It is a perspective view which looked at the industrial robot shown in FIG. 1 from the other side. FIG. 5 is a cross-sectional view taken along the line AA shown in FIG. It is a side view of the state where the industrial robot shown in FIG. 1 is moved forward. (A) is a schematic diagram for explaining the movable range of the link mechanism of the industrial robot according to the present embodiment, and (b) is a schematic for explaining the movable range of the link mechanism of the conventional industrial robot. It is a figure.

The industrial robot (hereinafter referred to as a robot) according to the embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 9.

1. 1. Overall Configuration of Robot 1 As shown in FIGS. 1 to 6, the robot 1 is a manipulator, and is a base 10, a link mechanism 20 attached to the base 10, and a wrist set attached to the link mechanism 20. It has a solid 30 and.

1-1. Base 10
The base 10 is installed on the installation surface F, and has a fixed base 11 fixed to the installation surface F and a swivel base 12 that swivels around a swivel axis Ja along a direction orthogonal to the installation surface F. It has. An output shaft (not shown) of a motor fixed to the fixed base 11 is connected to the swivel base 12. As a result, the swivel base 12 is swiveled around the swivel shaft Ja with respect to the fixed base 11.

1-2. Link mechanism 20
The link mechanism 20 includes first to third arms 21 to 23. The first arm 21 is rotatably pivotally attached to the swivel base 12 of the base 10 on the front side of the robot 1, that is, on the wrist assembly 30 side. Specifically, a connecting portion 21a is formed at one end (base end portion) of the first arm 21, and the connecting portion 21a is connected to the swivel base 12 of the base 10. As a result, the first arm 21 becomes pivotally (rotatable) with respect to the base 10 around the first rotation axis J1 orthogonal to the rotation axis Ja.

The first arm 21 is a support arm that supports a member on the tip side from the fourth arm 24 pivotally attached to the link mechanism 20, and has higher rigidity than the other arms of the link mechanism 20. Specifically, the first arm 21 has a larger maximum thickness in the direction along the first rotation axis J1 than the second arm 22 and the third arm 23.

The second arm 22 is rotatably pivotally attached to the swivel base 12 of the base 10 on the rear side of the robot 1. Specifically, a connecting portion 22a is formed at one end (base end portion) of the second arm 22, and the connecting portion 22a is connected to the swivel base 12 of the base 10. As a result, the second arm 22 becomes pivotal (rotatable) with respect to the base 10 around the second rotation axis J2 parallel to the first rotation axis J1. Further, the first arm 21 and the second arm 22 are arranged at positions offset to one side with respect to the turning axis Ja. As a result, a space is formed between the fourth arm 24 and the base 10, so that the movable range of the fourth arm 24 can be secured.

The third arm 23 is rotatably pivotally attached to the other end (tip portion) of the first arm 21 and the other end (tip portion) of the second arm at both ends thereof. Specifically, as will be described later, a joint shaft 23a corresponding to a connecting portion connected to the first arm 21 is formed at one end of the third arm 23. The joint shaft 23a is housed in a receiving portion 21b corresponding to a connecting portion formed at the other end of the first arm 21. As a result, the third arm 23 becomes pivotally movable (rotatable) with respect to the first arm 21 around the third rotation axis J3 parallel to the first rotation axis J1, and is pivotally supported by the first arm 21. Will be done.

On the other hand, at the other end of the third arm 23, a connecting portion 23b connected to the connecting portion 22b formed at the other end (tip portion) of the second arm 22 is formed. As a result, the third arm 23 becomes pivotal (rotatable) with respect to the second arm 22 around the fourth rotation axis J4 parallel to the third rotation axis J3. The second arm 22 and the third arm 23 are auxiliary arms for stabilizing the pivotal movement of the first arm 21.

In the present embodiment, when the link mechanism 20 is viewed from the horizontal direction (in the side view of the robot 1), the distance from the first rotation axis J1 to the third rotation axis J3 and the distance from the second rotation axis J2 to the fourth rotation axis J4 The distances to are equal. Further, the distance from the first rotation axis J1 to the second rotation axis J2 is equal to the distance from the third rotation axis J3 to the fourth rotation axis J4. As a result, the link mechanism 20 becomes a parallel link mechanism, and during operation, the first arm 21 and the second arm 22 are held so as to have a parallel positional relationship, and the movable range of the link mechanism 20 can be expanded.

Further, as shown in FIGS. 2 and 6, a first motor 31 that rotates around the first rotation axis J1 is connected to one end (base end portion) of the first arm 21 and is connected to the first motor 31. The output of the first arm 21 pivots (rotates) relative to the base 10. Along with the pivoting of the first arm 21, the third arm 23 pivotally attached to the first arm 21 and the second arm 22 pivotally attached to the third arm 23 are relatively relative to each rotation axis. The link mechanism 20 can be operated in the front-rear direction of the robot 1 by pivoting.

1-3. Wrist assembly 30
Further, the wrist assembly 30 is pivotally attached to the link mechanism 20. Specifically, the wrist assembly 30 includes a fourth arm (upper arm) 24, and the fourth arm 24 is rotatably pivotally attached to the link mechanism 20. The fourth arm 24 includes an arm body 24a corresponding to the arm portion of the robot 1 and a connecting portion 24b corresponding to the elbow portion of the robot 1 and connected to the link mechanism 20.

As shown in FIG. 5, the connecting portion 24b of the fourth arm 24 is the other end of the first arm 21, when the side on which the third arm 23 is arranged is one side with respect to the first arm 21. It is rotatably pivotally attached to the link mechanism 20 so as to be arranged on the other side of the first arm 21.

Specifically, the connecting portion 24b of the fourth arm 24 is rotatably pivotally attached to the joint shaft 23a of the third arm 23 around the third rotation shaft J3. In the present embodiment, as shown in FIGS. 4 and 5, the rotation axes of the first arm 21 and the fourth arm 24 with respect to the third arm 23 are the same rotation axes as the third rotation axis J3.

Here, the pivoting of the fourth arm 24 with respect to the third arm 23 is performed by the second motor 32. The second motor 32 is fixed to the connecting portion 24b of the fourth arm 24, and the output shaft 32b of the second motor 32 is connected to the third arm 23 so as to pivot around the fourth rotation shaft J4. (See, for example, FIG. 7). As a result, the fourth arm 24 can be rotated with respect to the third arm 23 together with the main body of the second motor 32.

The arm body 24a of the fourth arm 24 is rotatably connected (connected) to the connecting portion 24b around a rotating shaft Jb along the axis. As shown in FIG. 3, a third motor 33 is fixed to the articulated portion 24b, and the output shaft (not shown) of the third motor 33 is such that the arm body 24a rotates on the rotation shaft Jb. Is connected to the arm body 24a. By driving the third motor 33, the arm body 24a can be rotated around the rotation shaft Jb with respect to the connecting portion 24b.

In the present embodiment, the rotation shaft Jb and the rotation shaft Ja are arranged on the same plane regardless of the operation of the robot 1. As a result, the rotation axis Jb intersects the rotation axis Ja, which is the central axis on which the rotation table 12 rotates, so that the fourth arm 24 is stable around the rotation axis Jb regardless of the rotation operation of the rotation table 12. Can be operated.

Further, a pair of grip portions 24c and 24c corresponding to the wrist portion of the robot 1 are formed at the tip of the arm body 24a, and an end effector (not shown) such as a welding torch is supported between them. The support arm 25 is attached. The support arm 25 swings (rotates) around the swing shaft Jc with respect to the fourth arm 24 by a motor, a power transmission belt, or the like built in the arm body 24a, and an end effector is attached to the support arm 25. The tip of the support arm 25 is configured to rotate around the rotation shaft Jd.

Power is supplied to the wrist assembly 30 of the robot 1 via the power cable 41 (see FIG. 7). As a result, electric power is supplied to each motor, and the rotation operation around the rotation shafts Jb, Jd, and the swing shaft Jc can be realized.

2. Positional relationship of the first to fourth rotation axes J1 to J4 As described above, the first to fourth rotation axes J1 to J4 extend in the same direction along the horizontal direction as shown in FIGS. 3 and 4. are doing. In the present embodiment, as shown in FIGS. 1 and 2, in the side view of the link mechanism 20, the second arm 22 is more than the first rotation axis J1 in which the first arm 21 and the base 10 rotate relative to each other. The second rotation shaft J2, in which the base 10 and the base 10 rotate relatively, is located higher than the installation surface F. Specifically, the second rotation axis J2 is higher than the first rotation axis J1 by a length d1.

As a result, as shown in FIG. 8, when the link mechanism 20 is moved, the movable range of the link mechanism 20 to the first arm 21 side (front side of the robot 1) can be expanded. So far, as shown in FIG. 9B, the link mechanism 20'of the first rotating shaft J1 and the second rotating shaft J2 having the same height as the installation surface F has been adopted. In this case, when the link mechanism 20'is pivoted to the first arm 21 side (front side of the robot 1) from the state where the first arm 21 stands up against the installation surface F, the first arm 21 is pivoted. The angle is the angle θ2.

However, as shown in FIG. 9A, in the present embodiment, the link mechanism 20 is located at a higher position on the second rotation axis J2 than on the first rotation axis J1 from the installation surface F. Therefore, when the link mechanism 20 is pivoted to the first arm 21 side (front side of the robot 1) from the state where the first arm 21 stands up against the installation surface F, the pivoting angle of the first arm 21 is changed. , The angle θ1 is larger than the above-mentioned θ2. As a result, the movable range of the link mechanism 20 to the first arm 21 side (front side of the robot 1) is wider than that shown in FIG. 9B.

As a result, as shown in FIG. 8, the tip and support arm of the fourth arm 24 rotatably pivotally attached to the link mechanism 20 on the first arm 21 side without increasing the size of the device. 25 can be moved more.

Further, in FIGS. 1 and 2, the robot 1 is in a posture in which the first arm 21 and the second arm 22 stand up in a direction orthogonal to the installation surface F. In this posture, the installation surface F on the fourth rotating shaft J4 on which the second arm 22 and the third arm 23 rotate is larger than the third rotating shaft J3 on which the first arm 21 and the third arm 23 rotate. It is in a high position from. The fourth rotation axis J4 is higher than the third rotation axis J3 by a length d2.

In this way, the third arm 23 is rotatably pivotally attached to the first arm 21 and the second arm 22 while satisfying the positional relationship between the third rotation axis J3 and the fourth rotation axis J4. The 1 arm 21 can be more pivotally moved to the front side of the robot 1.

As a result, on the first arm 21 side, the fourth arm 24 can be moved more toward the tip side of the link mechanism 20. In particular, in the present embodiment, by making the length d1 and the length d2 equal, the distance from the first rotation axis J1 to the third rotation axis J3 and the distance from the second rotation axis J2 to the fourth rotation axis J4. Are equal. As a result, the first arm 21 can be further pivoted toward the front side of the robot 1.

3. 3. Mounting structure of the fourth arm 24 and positional relationship with the link mechanism 20 As described above, in the present embodiment, the first arm 21 receives the joint shaft 23a of the third arm 23 from one side of the first arm 21. The receiving portion 21b pivotally supports the third arm 23 via the bearing 6 (see FIGS. 3 and 7 and the like). In this way, on one side of the first arm 21, the third arm 23 is pivotally attached to the first arm 21 so as to be rotatable around the third rotation axis J3.

The receiving portion 21b is a substantially cylindrical portion having a hollow portion for accommodating the joint shaft 23a of the third arm 23. The joint shaft 23a has a cylindrical or cylindrical shape as long as the third arm 23 is rotatable with respect to the first arm 21 while being housed inside the receiving portion 21b of the first arm 21. It may be. Further, the joint shaft 23a may have a structure that is removable from the third arm 23.

Further, as shown in FIG. 7, as described above, the connecting portion 24b of the fourth arm 24 has the third rotation axis J3 with respect to the joint shaft 23a of the third arm 23 on the other side of the first arm 21. It is pivotally attached so that it can rotate around. Specifically, as described above, the connecting portion 24b of the fourth arm 24 rotates on the joint shaft 23a of the third arm 23 accommodated in the receiving portion 21b of the first arm 21 via the second motor 32. It is freely pivoted.

By adopting such a structure, the robot 1 arranges the third arm 23 on one side of the first arm 21 at the other end (tip portion) of the first arm 21, and arranges the third arm 23 on the other side of the first arm 21. The fourth arm 24 can be arranged in. Further, the fourth arm 24 can be rotatably pivotally attached to the third arm 23.

Therefore, since the third arm 23 and the fourth arm 24 are arranged so as to sandwich the first arm 21, mechanical interference between the third arm 23 and the fourth arm 24 can be avoided. In particular, since the first arm 21 is a support arm that supports the tip end side from the fourth arm 24, its maximum thickness is thicker than that of the third arm 23, as described above. Therefore, the third arm 23 and the fourth arm 24 are arranged apart from each other by the thickness of the first arm 21, so that the first arm 21 and the fourth arm 24 are separated from the third arm 23. It is possible to avoid mechanical interference between the third arm 23 and the fourth arm 24 as compared with the case where they are arranged so as to be sandwiched.

Further, the first arm 21 and the fourth arm 24 do not directly move. That is, since the power of the first motor 31 is not directly transmitted to the fourth arm 24 via the first arm 21, the power of the second motor 32 is efficiently transmitted to the third arm 23. It can be transmitted to the pivotally attached fourth arm 24.

As shown in FIGS. 3 and 7, in the present embodiment, the receiving portion 21b of the first arm 21 and the connecting portion 24b of the fourth arm form a space S for accommodating the power cable 41. The space S is covered by attaching the cover 61 to the connecting portion 24b of the fourth arm 24. By adopting such a structure, the power cable 41 is accommodated in the space S on the other side of the first arm 21 without being affected by the relative pivotal movement between the first arm 21 and the third arm 23. be able to.

Further, in the present embodiment, as shown in FIG. 7, the joint shaft 23a of the third arm 23 is accommodated by the receiving portion 21b of the first arm 21, and the joint shaft 23a of the third arm 23 accommodates the second motor 32. The third arm 23 is connected via the output shaft 32b of the above. As a result, the rotation shaft on which the first arm 21 and the third arm 23 rotate and the rotation shaft on which the third arm 23 and the fourth arm 24 rotate become the same third rotation shaft J3.

In this way, by matching the rotation axis in which the first arm 21 and the third arm 23 rotate relative to each other and the rotation axis in which the third arm and the fourth arm rotate relatively, the robot When 1 is operated, the relative rotation of these arms can be stabilized. Further, since these arms are rotated by the common third rotation shaft J3, a structure that suppresses mechanical interference between these arms can be adopted. As a result, the movable range of the link mechanism 20 does not have to be limited due to the pivotal movement of the fourth arm 24 with respect to the link mechanism 20.

Further, in the present embodiment, as described above, the swivel shaft Ja of the base 10 and the swivel shaft Jb of the fourth arm 24 are arranged on the same plane (see FIGS. 1 and 4 and the like). .. In addition to this, since the fourth arm 24 is arranged on the other side of the first arm 21, a space is formed between the base 10 and the fourth arm 24 (see FIGS. 4 and 6). ). As a result, the range of movement of the wrist assembly 30 including the fourth arm 24 can be further expanded, and the fourth arm 24 is stabilized around the rotation shaft Jb regardless of the rotation operation of the swivel base 12. Can be operated.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs are designed without departing from the spirit of the present invention described in the claims. You can make changes.

1: Robot (industrial robot), 10: Base, 11: Fixed base, 12: Swing base, 20: Link mechanism, 21: 1st arm, 21b: Receiving part, 22: 2nd arm, 23: 3rd Arm, 23a: Joint shaft, 24: 4th arm, 25: Support shaft, 30: Wrist assembly, 41: Power cable, Installation surface F, J1 to J4: 1st to 4th rotation axes, Ja: Swivel axis, Jb: 5th rotation shaft

Claims (4)

The base installed on the installation surface and
A first arm and a second arm whose one end is rotatably pivotally attached to the base, and a third arm which is rotatably pivotally attached to the other end of the first arm and the second arm. With the link mechanism
On the first arm side, a fourth arm rotatably pivotally attached to the link mechanism is provided.
The second rotating shaft in which the second arm and the base rotate relative to each other is higher than the first rotating shaft in which the first arm and the base rotate relative to each other. position near is,
In a posture in which the first arm and the second arm stand up along a direction orthogonal to the installation surface, the second arm is more than a third rotation axis on which the first arm and the third arm rotate. The fourth rotating shaft on which the arm and the third arm rotate is located higher than the installation surface.
The distance from the first rotation axis to the third rotation axis and the distance from the second rotation axis to the fourth rotation axis are equal.
The base includes a fixed base fixed to an installation surface and a swivel base that pivotally attaches the link mechanism and swivels around a swivel shaft with respect to the fixed base.
The fourth arm is rotatably connected to the arm body and the arm body around the rotation axis with the axis of the arm body as a rotation axis, and is rotatable to the third arm. It has an articulation part, which is pivotally attached to the
An industrial robot characterized in that the swivel shaft and the swivel shaft are arranged on the same plane . At the other end of said first arm, according to claim 1, wherein the third arm is arranged on one side of the first arm, wherein the fourth arm on the other side of the first arm is located industrial robot according to. A claim characterized in that the third rotation axis on which the first arm and the third arm rotate and the rotation axis on which the third arm and the fourth arm rotate are the same rotation axis. Item 2. The industrial robot according to item 1 or 2. A support arm that supports the end effector is attached to the tip of the fourth arm, the support arm swings with respect to the fourth arm, and the tip of the support arm is the support arm. The industrial robot according to any one of claims 1 to 3, wherein the robot rotates with respect to the axis.

Images