阅读说明：本技术 机器人的动力传递机构以及使用该动力传递机构的机器人 (Power transmission mechanism for robot and robot using the same ) 是由 照沼智明 中村亮介 关根英则 于 2021-04-30 设计创作，主要内容包括：本发明提供具备适于减少在机器人的电动马达与可动连杆机构之间的动力传递机构所产生的过大的负荷的小型的转矩限制机构的机器人的动力传递机构、以及使用该动力传递机构的机器人。转矩限制机构(15)具备：球塞(17),其与电动马达(12)的旋转部(13)连结,具备被压缩弹簧(20)施力后的球主体(19)；以及卡合凹部(18),其与可动连杆机构(11)的被旋转部连结,供球塞(17)的球主体(19)嵌入而成为卡合状态,并且具有若对球主体(19)作用预定的限制转矩则解除卡合状态的倾斜度。由此,能够得到适于减少机器人的电动马达(12)与可动连杆机构(11)之间的动力传递机构所产生的过大的负荷的小型的转矩限制机构。(The invention provides a power transmission mechanism of a robot, which is provided with a small-sized torque limiting mechanism suitable for reducing excessive load generated by the power transmission mechanism between an electric motor and a movable link mechanism of the robot, and the robot using the power transmission mechanism. The torque limiting mechanism (15) is provided with: a ball plunger (17) that is connected to a rotating part (13) of the electric motor (12) and that is provided with a ball body (19) that is biased by a compression spring (20); and an engagement recess (18) that is connected to a rotated part of the movable link mechanism (11), that is engaged by fitting a ball body (19) of the ball plug (17), and that has a gradient such that the engaged state is released when a predetermined restriction torque acts on the ball body (19). Thus, a small torque limiting mechanism suitable for reducing an excessive load generated by a power transmission mechanism between an electric motor (12) and a movable link mechanism (11) of a robot can be obtained.)

1. A power transmission mechanism for a robot, comprising a torque limiting mechanism mounted between a rotating part of an electric motor and a rotated part of a movable link mechanism,

the torque limiting mechanism includes: a ball plunger coupled to the rotating portion of the electric motor and including a ball body biased by a compression spring; and an engagement recess portion that is connected to the rotated portion of the movable link mechanism, that is engaged by fitting the ball body of the ball plunger, and that has an inclination such that the engaged state is released when a predetermined restriction torque is applied to the ball body.

2. The power transmission mechanism of a robot according to claim 1,

the torque limiting mechanism further includes a torque adjusting means for adjusting the limiting torque for releasing the engagement state between the ball body of the ball plunger and the engagement recess.

3. The power transmission mechanism of a robot according to claim 2,

the torque adjusting means of the torque limiting mechanism is spring pressure adjusting means for adjusting a spring pressure of the compression spring.

4. The power transmission mechanism of a robot according to claim 3,

the spring pressure adjusting means of the torque limiting mechanism includes a stopper means for setting a distance between the ball plunger and the engaging recess to a predetermined distance.

5. The power transmission mechanism of a robot according to claim 4,

the ball plunger and/or the stopper means are colored in a color or a shape correlated with the value of the limit torque.

6. The power transmission mechanism of a robot according to claim 2,

the torque adjusting means of the torque limiting mechanism is constituted by an exchangeable engaging recess forming base, and the engaging recess forming base changes an inclination angle of the engaging recess to adjust the limiting torque.

7. The power transmission mechanism of a robot according to claim 6,

the engaging recess forming base is colored in a color or a shape related to the value of the limit torque.

8. A robot having a power transmission mechanism of the robot in which a rotating portion of an electric motor and a rotated portion of a movable link mechanism are connected by a torque limiting mechanism,

the power transmission mechanism of the robot is the power transmission mechanism of the robot described in any one of claims 1 to 7.

Technical Field

The present invention relates to a power transmission mechanism for a robot and a robot using the power transmission mechanism.

Background

In a power transmission mechanism for a robot including an electric motor and a movable link mechanism connected to the electric motor, when the movable link mechanism collides with an obstacle and operation is restricted or the electric motor generates an excessive torque due to some abnormality, an excessive load (torque) may be generated between the electric motor as a driving portion and the movable link mechanism as a driven portion to which power of the electric motor is transmitted, and a portion (so-called joint portion) where the electric motor and the movable link mechanism are connected may be damaged. Therefore, a mechanical "torque limiting mechanism" is disposed at a portion where the electric motor and the movable link mechanism are coupled.

An example of the torque limiting mechanism is described in patent document 1 (japanese patent application laid-open No. 2006-255829) below. In the torque limiting mechanism of patent document 1, when rotation from the rotary shaft of the electric motor is transmitted to the movable link mechanism side and a torque equal to or greater than a predetermined torque (hereinafter referred to as a limiting torque) set in advance is generated between the rotary shaft of the electric motor and the movable link mechanism, slip (idling) is generated to limit the transmission of the torque to be lower than the predetermined torque.

The torque limiting mechanism of patent document 1 includes a first torque transmission portion having a convex portion and a second torque transmission portion having a concave portion corresponding to the convex portion, the convex portion is fitted into the concave portion in a biased state to transmit torque via the first torque transmission portion and the second torque transmission portion, and when torque equal to or greater than a limiting torque is applied, the fitted state of the convex portion and the concave portion is released (offset), and idling is generated between the first torque transmission portion and the second torque transmission portion.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2006 and 255829

Disclosure of Invention

Problems to be solved by the invention

However, patent document 1 does not disclose or suggest any specific configuration of a torque limiting mechanism for reducing an excessive load (torque) generated at a coupling portion between an electric motor and a movable link mechanism of a robot. In particular, a space for arranging the electric motor and the movable link mechanism (a space for arranging joint portions of the arm portion and the leg portion) in the robot is narrow, and a compact torque limiting mechanism is required.

The purpose of the present invention is to provide a power transmission mechanism for a robot, which is provided with a small-sized torque limiting mechanism that can reduce an excessive load (torque) generated between an electric motor and a movable link mechanism of the robot and that can be disposed in a narrow space, and a robot using the power transmission mechanism.

Means for solving the problems

The present invention is a power transmission mechanism for a robot including a torque limiting mechanism interposed between a rotating portion of an electric motor and a rotated portion of a movable link mechanism, the torque limiting mechanism including: a ball plunger coupled to a rotating portion of the electric motor and including a ball body biased by a compression spring; and an engagement recess portion which is connected to a rotated portion of the movable link mechanism, into which a ball body of the ball plunger is fitted to be in an engaged state, and which has an inclination such that the engaged state is released when a predetermined torque is applied to the ball body.

The effects of the invention are as follows.

According to the present invention, it is possible to obtain a power transmission mechanism for a robot including a small-sized torque limiting mechanism that can reduce an excessive load (torque) generated between an electric motor and a movable link mechanism of the robot and that can be disposed in a narrow space, and a robot using the power transmission mechanism.

Drawings

Fig. 1 is a configuration diagram showing a structure of a movable link mechanism of a robot.

Fig. 2 is a perspective view of the movable link mechanism of the robot of fig. 1 as viewed obliquely.

Fig. 3 is an exploded perspective view of the movable link mechanism of the robot of fig. 1.

Fig. 4 is an enlarged view of the torque limiting mechanism shown in fig. 1.

Fig. 5 is a sectional view illustrating an adjusting unit for adjusting the urging force of the ball plunger.

Fig. 6 is a sectional view illustrating an adjusting unit for efficiently adjusting the acting force of the ball plunger.

Fig. 7A is a cross-sectional view illustrating an engagement recess portion with a large inclination angle for engagement of the ball plunger.

Fig. 7B is a cross-sectional view illustrating the engagement recess with which the ball plunger is engaged, the angle of inclination of which is small.

Description of the symbols

10-drive section, 11-movable link mechanism, 12-electric motor, 13-rotating section, 14-transmission link, 15-torque limiting mechanism, 16-plunger holding section, 17-ball plunger, 18-engaging recess, 19-ball body, 20-compression spring, 21-fixing bolt, 22-plunger fixing cylinder, 23-transmission plate, 24-fixing link, 25-plunger body cylinder, 26-spring pressure adjusting screw, 27-large diameter section, 28-stopper member, 29-engaging recess form a base.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the embodiments described below, and various modifications and applications in the technical concept of the present invention are included in the scope thereof.

First, the configurations of the power transmission mechanism and the torque limiting mechanism of the robot to which the present invention is applied will be briefly described with reference to fig. 1 and 2. Further, the power transmission mechanism is a combination of an electric motor and a movable link mechanism driven by the electric motor. The movable link mechanism constitutes an arm portion and a leg portion of the robot.

The power transmission mechanism of the robot is composed of a drive unit 10 and a movable link mechanism 11 driven by the drive unit 10. The driving unit 10 includes an electric motor 12, and the electric motor 12 outputs a rotational force from a rotating unit 13. The movable link mechanism 11 includes a transmission link 14, and the movable link mechanism 11 performs a rotating operation or a swinging operation by the transmission link 14. The transmission link 14 is a rotated portion rotated by the rotating portion 13, and the transmission link 14 and the rotating portion 13 of the electric motor 12 are mechanically coupled by a torque limiting mechanism 15.

The torque limiting mechanism 15 is constituted by a plunger holding portion 16 coupled to the rotating portion 13 of the electric motor 12 by a bolt 21, a ball plunger 17 held by the plunger holding portion 16, and an engagement recess 18 formed in the transmission link 14 into which a ball body 19 of the ball plunger 17 is fitted. As will be understood from fig. 4 described below, the ball body 19 is formed by a combination of a spherical surface portion and a cylindrical portion, but may be a spherical ball. Further, the shape of the transfer link 14 is as shown in fig. 3 and will be described in detail below.

The engagement recess 18 formed in the transmission link 14 is formed in a "concave" shape having a predetermined inclination angle, and the tip of the ball body 19 of the ball plunger 17 is fitted into the recess and engaged therewith. A compression spring 20 as an elastic means is housed in the ball plunger 17, and the ball body 19 is biased by the compression spring 20 so as to protrude toward the engagement recess 18.

As a result, the ball body 19 is pressed against the engagement recess 18 with a predetermined pressure. By adjusting the pressure of this pressure bonding, the restraining torque can be adjusted, but the adjustment direction thereof, the structure for adjustment, will be described below.

Then, the rotation of the rotating portion 13 of the electric motor 12 is transmitted to the plunger holding portion 16, and the ball plunger 17 is rotated. Further, since the ball body 19 of the ball plunger 17 engages with the engagement recess 18 of the transmission link 14, the rotation of the ball plunger 17 is transmitted to the transmission link 14. Thereby, the transmission link 14 rotates, and the movable link mechanism 11 performs a rotating operation or a swinging operation by the transmission link 14.

Fig. 3 shows details of the torque limiting mechanism 15 to which the present invention is applied. A plunger holding portion 16 is fixed to an end surface of the rotating portion 13 of the electric motor 12 by a bolt 21 (see fig. 2). Thereby, the rotating portion 13 and the plunger holding portion 16 can be integrally rotated.

The plunger holding portion 16 is formed with two plunger fixing cylinder portions 22, and the ball plunger 17 is inserted into and fixed to a hole portion 22H of the plunger fixing cylinder portion 22.

The transmission link 14 includes a planar transmission plate 23 disposed between the end surface of the rotating portion 13 and the plunger holding portion 16, and a fixed link 24 formed by bending the transmission plate 23 in a substantially vertical direction toward the opposite side of the electric motor 12. The fixed link 24 is fixed to another component constituting the movable link mechanism 11, and transmits the rotation of the transmission plate 23 to the movable link mechanism 11.

An engagement recess 18 is formed in a surface of the transmission plate 23 on the plunger holding portion 16 side at a position corresponding to the position of the plunger fixing cylinder portion 22, and the ball body 19 of the ball plunger 17 is engaged with the engagement recess 18 in a fitting manner as described above. Thereby, the rotation of the ball plunger 17 is transmitted to the transmission plate 23 via the engagement recess 18.

Next, details of the ball plunger 17 and the transmission plate 23 of the torque limiting mechanism will be further described.

In fig. 4, the ball plunger 17 fixed to the plunger fixing cylinder 22 is composed of a bottomed plunger body cylinder 25, a compression spring 20 disposed in a space formed inside the plunger body cylinder 25, and a ball body 19 biased toward the transmission plate 23 side by the compression spring 20.

The engagement recess 18 formed in the transmission plate 23 is formed in a "concave" shape having a predetermined inclination angle, and the tip end of the ball body 19 of the ball plunger 17 is fitted into the concave to be engaged. The concave shape can be formed by countersinking.

The torque can be regulated by changing the inclination angle (θ) of the engagement recess 18. The larger the angle (inclination angle θ) of the 180 ° opposed surface of the engagement recess 18, the smaller the restricted torque, and the smaller the angle (inclination angle θ), the larger the restricted torque. Further, the torque can be regulated by regulating the inclination angle of the engaging recess 18, but the direction of regulation and the structure for regulation will be described below.

As described above, the ball body 19 is pressed against the engagement recess 18 formed in the transmission plate 23 by the compression spring 20, and the rotation of the rotating portion 13 of the electric motor 12 can be transmitted to the transmission plate 23 in a state where the ball body 19 is engaged with the engagement recess 18.

Here, when the movable link mechanism 11 collides with an obstacle and operation is restricted, or an excessive torque is generated in the electric motor 12 due to some abnormality, an excessive load (torque) is generated between the electric motor 12 as a driving portion and the transmission link 14 that transmits the power of the electric motor 12, and a damage may be generated in a coupling portion between the electric motor 12 and the movable link mechanism 11.

Therefore, in the torque limiting mechanism 15, when an excessive load (torque) is generated between the rotating portion 13 of the electric motor 12 and the transmission link 14 that transmits the rotation, the ball main body 19 of the ball plunger 17 compresses the compression spring 20, moves along the inclined Surface (SLP) of the engagement recess 18 formed in the transmission plate 23, and operates to release the engagement state with the engagement recess 18.

When the engagement state is released, the rotation portion 13 of the electric motor 12 and the transmission link 14 are disconnected from each other, and the transmission of torque is interrupted. Further, the torque when the engagement between the ball body 19 and the engagement recess 18 is released becomes the limit torque.

Thus, even if an excessive load (torque) is generated between the electric motor 12 as a driving portion and the transmission link 14 that transmits the power of the electric motor 12, damage can be avoided from occurring at the coupling portion between the electric motor 12 and the movable link mechanism 11.

As described above, in the present embodiment, in the power transmission mechanism of the robot including the torque limiting mechanism attached to be interposed between the rotating portion of the electric motor and the rotated portion of the movable link mechanism, the torque limiting mechanism includes: a ball plunger coupled to a rotating portion of the electric motor and including a ball body biased by a compression spring; and an engagement recess portion which is connected to a rotated portion of the movable link mechanism, into which a ball body of the ball plunger is fitted to be in an engaged state, and which has an inclination such that the engaged state is released when a predetermined torque is applied to the ball body.

Thus, a small torque limiting mechanism can be obtained which can reduce an excessive load (torque) generated between the electric motor and the movable link mechanism of the robot and can be disposed in a narrow space.

However, as described above, in such a torque limiting mechanism, it is required to adjust the limit torque in accordance with the product specification of the robot. For example, from the viewpoint of production, it is preferable to use the same torque limiting mechanism 15 for the arm and leg of the robot. However, the limit torques at the arm and leg portions of the robot may be different from each other, or the limit torques may need to be readjusted, and it is required to adjust the limit torques. To cope with such a demand, embodiments shown below are proposed.

The basic idea of the present embodiment is that the torque limiting mechanism includes: a ball plunger coupled to a rotating portion of the electric motor and including a ball body biased by a compression spring; and a torque adjusting means that is connected to the rotated portion of the movable link mechanism, and that adjusts a limit torque for releasing the engagement between the ball body of the ball plunger and the engagement recess while the ball body of the ball plunger is fitted into the engagement. Specific embodiments are described below.

Fig. 5 shows an example of adjusting the spring pressure of the compression spring 20 as torque adjusting means for adjusting the restriction torque for releasing the engagement state between the ball plunger 17 and the engagement recess 18. There are two types of adjustment of the spring pressure of the compression spring 20, and two examples are described below. In fig. 5, two examples are shown together, but at least either method may be used.

First, as a first example, this example is a method of adjusting the spring pressure of the compression spring 20 by moving the ball plunger 17 itself relative to the plunger fixed cylinder portion 22. In fig. 5, a screw groove is formed inside the hole portion 22H of the plunger fixing cylinder portion 22, and a screw groove is also formed on the outer periphery of the plunger main body cylinder portion 25 of the ball plunger 17 so as to be screwed into the screw groove.

When the ball plunger 17 is rotated to adjust the relative position with respect to the plunger fixing cylinder 22, the pressure contact state with the engagement recess 18 formed in the transmission plate 23 can be adjusted. That is, when the ball plunger 17 approaches the transmission plate 23 and the distance between the ball plunger 17 and the transmission plate 23 becomes shorter, the ball body 19 is pushed into the space formed inside the plunger body cylinder portion 25. Thereby, the spring pressure (compression force) of the compression spring 20 increases, and the restriction torque for releasing the engagement state between the ball plunger 17 and the engagement recess 18 increases.

On the other hand, when the ball plunger 17 is separated from the transmission plate 23 and the distance between the ball plunger 17 and the transmission plate 23 becomes longer, the ball body 19 is pushed out from the space formed inside the plunger body cylinder portion 25. Thereby, the spring pressure of the compression spring 20 is reduced, and the restriction torque for releasing the engagement state of the ball plunger 17 and the engagement recess 18 is reduced.

Next, as a second example, this is a method of adjusting the spring pressure of the compression spring 20 by disposing the spring pressure adjusting screw 26 on the side of the compression spring 20 accommodated in the internal space of the ball plunger 17 opposite to the ball main body 19. In fig. 5, a thread groove is formed in the plunger main body tube portion 25, and a thread groove is also formed on the outer periphery of the spring pressure adjusting screw 26 so as to be screwed into the thread groove.

When the spring pressure adjustment screw 26 is rotated to adjust the relative position with respect to the plunger main body cylindrical portion 25, the pressure contact state with the engagement recess 18 formed in the transmission plate 23 changes. That is, when the spring pressure adjusting screw 26 is rotated, the spring pressure adjusting screw 26 approaches the ball body 193, and the distance between the spring pressure adjusting screw 26 and the ball body 19 becomes shorter, the spring pressure of the compression spring 20 becomes larger, and the restriction torque for releasing the engagement state between the ball plunger 17 and the engagement recess 18 becomes larger.

On the other hand, when the spring pressure adjusting screw 26 is separated from the ball body 193 and the distance between the spring pressure adjusting screw 26 and the ball body 19 becomes longer, the spring pressure of the compression spring 20 becomes smaller, and the restriction torque for releasing the engagement state of the ball plunger 17 and the engagement recess 18 becomes smaller.

By adjusting the spring pressure of the compression spring 20 in this way, the restriction torque for releasing the engagement state between the ball plunger 17 and the engagement recess 18 can be adjusted. Therefore, even when the limit torques of the arm and the leg of the robot are different or when the limit torque needs to be readjusted, the robot can sufficiently cope with the situation.

As is apparent from the first and second examples, the torque adjusting means of the torque limiting mechanism 15 is spring pressure adjusting means for adjusting the spring pressure of the compression spring 20.

In the first example described above, in order to efficiently adjust the spring pressure of the compression spring 20 in the work site, the configuration shown in fig. 6 may be employed in the first example described above.

In fig. 6, a large diameter portion 27 is formed on the ball plunger 17 on the side opposite to the ball main body 19, and a stopper member 28 is interposed between the large diameter portion 27 and an end surface of the plunger fixing cylinder portion 22 (end surface on the opposite side of the transmission plate 23) so as to be sandwiched. The relative position of the ball plunger 17 and the plunger fixing cylinder 22 is determined by the thickness of the stopper member 28, and the pressure contact state with the engagement recess 18 formed in the transmission plate 23 is adjusted.

For example, when replacing the ball plunger 17, the current ball plunger 17 is pulled out, and a new ball plunger 17 to be replaced is screwed to a position where the ball plunger 17 cannot be rotated by the stopper member 28, whereby the amount of protrusion of the ball plunger 17 can be easily adjusted to a predetermined amount. The protruding amount is equivalent to the spring pressure of the compression spring 20, and the limit torque can be adjusted.

As described above, in the present embodiment, the spring pressure adjusting means of the torque limiting mechanism 15 includes the stopper means for setting the distance between the ball plunger 17 and the engagement recess 18 to a predetermined distance.

As the stopper member 28, a nut, a washer, a gasket, an O-ring, or the like can be used. For example, when joint portions of an arm portion and a leg portion of the robot are set to have different plunger projection amounts (i.e., torque limits), if the ball plunger 17 to which the stopper member 28 is attached is prepared in advance, the operation can be performed efficiently.

In addition, when the arm and the leg of the robot are recognized, it is advantageous to color the ball plunger 17 and/or the stopper member 28 in advance with paint or the like, for example. For example, the ball plunger 17 and the stopper member 28 for the arm portion are colored blue, and the ball plunger 17 and the stopper member 28 for the leg portion are colored red. This makes it possible to quickly see the ball plug 17 for the arm and the ball plug 17 for the leg, thereby improving the work efficiency. Also, instead of different colors, the shape may be changed.

In this way, the ball plunger 17 and/or the stopper member 28 is colored in a color associated with the value of the restriction torque or formed in a shape associated with the value of the restriction torque.

In the above description, the example of adjusting the spring pressure of the compression spring 20 has been described as the torque adjusting means for adjusting the limit torque, but the limit torque may be adjusted according to the inclination angle of the inclined surface of the engagement recess 18.

As described above, the limit torque can be adjusted by changing the inclination angle (θ) of the engagement recess 18. The larger the angle (inclination angle θ) of the 180 ° opposed surface of the engagement recess 18, the smaller the restricted torque, and the smaller the angle (inclination angle θ), the larger the restricted torque. Therefore, in the present embodiment, the limit torque is adjusted by making the engagement recess 18 replaceable.

Fig. 7A and 7B show the vicinity of the engagement recess 18 in which the ball body 19 of the ball plunger 17 engages in an enlarged manner. The engaging recess 18 is formed in an engaging recess forming base 29, and the engaging recess forming base 29 is configured to be replaceable with respect to the transmission plate 23.

The engagement recess forming base 29 is configured to be detachable (replaceable) from the transmission plate 23. Specifically, a screw groove is formed on the outer periphery of the engagement recess forming base 29, and a screw groove is also formed in the receiving hole of the transmission plate 23 that receives the engagement recess forming base 29.

Therefore, the base 29 is formed by selecting a necessary engagement recess and is attached to the transmission plate 23 by screwing, so that the limit torque can be easily adjusted.

Fig. 7A shows an example in which the angle (inclination angle θ 1) of the 180 ° opposed surface of the engagement recess 18 is large, and fig. 7B shows an example in which the angle (inclination angle θ 2) of the 180 ° opposed surface of the engagement recess 18 is small. In this way, when the engagement recess corresponding to the required limit torque is selected to form the base 29 and the base is attached to the transmission plate 23, the limit torque can be easily adjusted. This makes it possible to make most of the components of the torque limiter mechanism 15 common, thereby reducing the production cost.

When the arm and leg of the robot are recognized, the engagement recess forming base 29 may be colored in advance with paint or the like, for example. For example, the engagement recess forming base 29 for the arm portion is colored blue, and the engagement recess forming base 29 for the leg portion is colored red. This makes it possible to quickly see the engagement recess forming base 29 for the arm or the leg, and to improve the work efficiency. Also, instead of different colors, the shape may be changed.

In this way, the engagement recess forming base 29 is colored in a color or a shape correlated with the value of the limit torque.

The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail to explain the present invention easily and understandably, and are not limited to having all the configurations described. Moreover, a part of the structure of one embodiment may be replaced with the structure of another embodiment, and the structure of another embodiment may be added to the structure of one embodiment. In addition, a part of the configuration of each embodiment can be added, deleted, or replaced with another configuration.