JPH0243679Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a robot joint, and more particularly, to a robot joint in which one joint is operated by a plurality of motors.

BACKGROUND ART For example, on the orthogonal axes of X _{, Y} , and Z shown in _FIG . For example, a range of an arbitrary angle α across X-X' on the X-Y plane centered on the intersection O of the Y and Z axes, and a range of arbitrary angle α centered on O ₁
Various mechanisms have been proposed for robot joints that can freely select a range of arbitrary angles β over a plane, for example, X ₁ -X ₁ '.

An example of this is shown in FIGS. 2 and 3. In addition, the third
The figure is a side view of FIG. 2.

In the figure, S ₁ , S ₅ , and S ₇ are axes arranged on the same axis. The bevel gears V ₁₁ and V ₃₁ attached to the ends of the shafts S ₁ and S ₅ are arranged facing each other at a predetermined interval, and between each bevel gear V ₁₁ and the bevel gear V ₃₁ , the shaft S ₁ ，
They are connected by a bevel gear V ₂₁ rotatably attached to the end of the shaft S ₄ arranged at right angles to S ₅ . Also, axis S ₇
The bevel gear V ₆₁ attached to the end of the shaft S ₅ and the bevel gear _{V 41} attached to the end of the shaft S ₅ are arranged facing each other at a predetermined interval. They are connected by a bevel gear V ₅₁ attached to the end of the shaft S ₆ disposed perpendicularly to each of S ₇ , S ₅ and the shaft S ₄ .
Furthermore, in each figure, A ₁ , A ₂ , and A ₃ are frames that support each gear shaft.

Therefore, in the figure, the angle α centered on the O ₁ −O ₁ ' axis passing through the axis S ₄ of the bevel gear V ₂₁ acts as one joint movement, and also passing through the axis S ₆ of the bevel gear V ₅₁ . _O2
The angle β around the −O ₂ ′ axis acts as the second joint. Here, the rotational force centered on O ₁ −O ₁ ′ is provided by motor M ₃ , and the rotational force centered on O ₂ −O ₂ ′ is provided by motor M ₂ . Motor M ₁ is used to rotate axis S ₇ and perform work beyond said joint.

That is, in FIG. 2, motor _M3 drives hollow drive shaft _S3 via spur gears _G3 and _G4 .
The drive shaft _S3 and the bevel gear _V13 are integral, the bevel gears _V13 and _V23 mesh with each other, and the bevel gear _V23 and the frame _A2 are integrally provided. Therefore, when the motor M ₃ rotates, the frame A ₂ freely rotates in the α direction around O ₁ −O ₁ ′.

On the other hand, motor _M2 drives drive shaft _S2 via spur gears _G1 and _G2 . i.e. drive shaft S ₂ and bevel gear
V ₁₂ is integrally provided and meshes with bevel gear V ₁₂ and bevel gear V ₂₃ , and bevel gear V ₂₂ meshes with bevel gear V ₃₂ . The bevel gear V ₂₁ can rotate freely about the axis S ₄ . Therefore, the rotational force of motor _M2 is directly transmitted to bevel gear _V32 .

The bevel gear V ₃₂ and the bevel gear V ₄₂ are integrally provided at both ends of the hollow shaft S ₈ , and the bevel gear V ₄₂ is further provided with a bevel gear.
It meshes with the V ₅₂ . And bevel gear V ₅₂
is integrated into frame A ₃ , so the motor
When M ₂ is driven, frame A ₃ can freely rotate in the β direction about the O ₂ −O ₂ ′ axis.

In this way, by driving the motors M ₂ and M ₃ , respectively, it is possible to freely rotate in the α and β directions around the O ₁ −O ₁ ′ and O ₂ −O ₂ ′ axes, respectively, to take any desired angle. It can act as a joint. On the other hand, the axis S ₇ is rotated by the motor M ₁ and therefore O ₁ −O ₁ ′,
Further robot movements can be performed through the O ₂ -O ₂ ' joint.

Problems to be Solved by the Invention The conventional robot joint described above can be manufactured with a relatively simple structure, but the problem is that each joint requires its own motors M ₂ and M ₃ . , each of these motors can only operate a single joint (that is, a single joint cannot be operated by multiple motors).
Therefore, the motors M ₂ and M ₃ are necessarily required to have a large output rating.

In reality, as the operating speed of robots has increased, each joint has come to require a motor with considerably higher output. It is not desirable to use motors for each joint.

Means and Effects for Solving the Problems The present invention solves the above problems by proposing a system in which the motion of one joint is driven by a plurality of motors. In other words, this invention is the fourth
If the two motors M ₁ and M ₂ can rotate the joint around O ₁ − O ₁ ' (rotation in the α direction) using the configuration shown below, the rated output of each motor M ₁ and M ₂ will be This was done from the viewpoint that the same effect as the above-mentioned conventional method can be expected even if the value is lowered. In addition, in this case O ₁
There is a view that there is not much advantage when comparing the case where rotations of the axes (α direction and β direction) are performed simultaneously around the −O ₁ ′ axis and the O ₂ −O ₂ ′ axis, respectively. In general, since the angles around the O ₁ −O ₁ ′ axis and the O ₂ −O ₂ ′ axis are different, the motors M ₁ , M ₂ , M ₃
It is possible to reduce the output of each and achieve miniaturization.

Accordingly, the present invention provides a joint of a robot in which the joint is driven by a motor and can further transmit rotation to the distal end side of the joint, wherein the joint is equipped with a differential gear mechanism, and the joint is equipped with a differential gear mechanism. The bevel gears on the input side and the bevel gears on the output side of the mechanism each consist of multiple large and small gears, and each gear is arranged on the same axis, and each gear on the input side and each gear on the output side are arranged on the same axis. Each gear on the input side is linked to a separate drive motor, and each gear on the output side is at least two integrally provided bevel gears for operating the joint. and a bevel gear for transmitting rotational power to the distal end side of the joint.

Embodiments The present invention will be described below with reference to embodiments shown in FIGS. 4, 5, and 6. Note that parts that are the same as those in the prior art will be described using the same reference numerals. In addition, the fourth
The figure is a sectional view, FIG. 5 is a right side view of FIG. 4, and FIG. 6 is a partial sectional view of the right side of FIG. 4. In addition, in the figure, the axes S ₁ , S ₂ , and S ₃ are configured with motors M ₁ , M ₂ , and M ₃ in the same manner as in Figure 1, so their interlocking relationship is shown schematically here. .

Now, in Fig. 4, driving motor _M3 ,
Rotate axis S ₃ clockwise and drive motor M ₂ at the same time to rotate axis
When S ₂ is rotated to the left, the bevel gears V ₁₃ and V ₁₂ on the input side, which are integral with the respective shafts S ₃ and S ₂ , are rotated in the right-handed and left-handed directions. Here, bevel gear V ₁₃
and bevel gear V ₃₃ mesh with each other, and bevel gear
V ₁₂ and V ₂₂ mesh with each other. On the other hand, bevel gear V ₃₃
and V ₄₃ mesh, and bevel gears V ₂₂ and V ₄₂ mesh,
Moreover, gears V ₄₂ and V ₄₃ are mechanically integrated.

As a result, a kind of differential gear mechanism is constituted by the bevel gear group including the bevel gears V ₁₃ , V ₁₂ , V ₂₂ , V ₃₃ and the bevel gears V ₄₂ , V ₄₃ . In addition, bevel gears V ₂₁ , V ₂₂ ,
V ₃₃ is free with respect to axis S ₄ . Therefore, if drive shafts S ₂ and S ₃ are driven in opposite directions at the same angular velocity by motors M ₂ and M ₃ as described above, each drive shaft
The bevel gears V ₄₂ and V ₄₃ on the output side, which are integrated with S ₂ and S ₃ , respectively, are centered on the O ₁ −O ₁ ' axis when the frame A ₁ is stationary as shown in Figures 4 and 6. In this state, frame A ₂ rotates in the +α and -α directions and functions as a joint.

On the other hand, drive the motors M ₂ and M ₃ to drive the drive shafts S ₂ and S ₃
If they are rotated in the same direction at the same angular velocity, the integrated bevel gears V ₄₂ and V ₄₃ will rotate, and the bevel gear V ₅₂ will rotate. _In this _case , +
There is no movement in the α and −α directions. Moreover, the rotational energy of the bevel gear V ₅₂ in this case is the same as that of the motors M ₂ and M ₃
By appropriately selecting the gear ratio, the output is evenly distributed, and the output becomes the sum of motors M ₂ and M ₃ .

This also means that the drive shafts S ₂ and S ₃ by the aforementioned motors M ₂ and M ₃ rotate at the same angular velocity and in opposite directions as a joint centered at O ₁ −O ₁ ′. The energy in the case of movements in the +α or -α direction will also be shared evenly by the motors M ₂ , M ₃ by judicious selection of their respective gear ratios. In this case, the motor when using the mechanism shown in Figure 2
With half the rating of M ₂ and M ₃ , it is possible to obtain the same speed and operating force as a joint.

Because of this mechanism, it is not possible to change the relative rotation direction of the hollow drive shafts S ₂ and S ₃ by the motors M ₂ and M ₃ , or to control the angular velocity of the respective drive shafts S ₂ and S ₃ . Accordingly, the load sharing between motors M ₂ and M ₃ can be changed arbitrarily.

In this case, +α or −α centered at O ₁ −O ₁ ′
The bevel gear V ₄₂ with the rotation of the frame A ₂ in the direction,
The V ₄₃ will also rotate. Here, the integrally provided bevel gears V ₄₂ and V ₄₃ are also integrally provided with the bevel gear V ₅₂ via the drive shaft S ₈ . As is clear from Figs. 4 and 5, the bevel gear V ₅₁ ,
V ₅₂ , V ₆₁ , V ₇₂ and the integral bevel gears V ₈₁ , V ₈₂ also constitute a kind of differential gear mechanism.

As mentioned above, as an example, as shown in FIGS. 4, 5, and 6, O ₁ −
The O ₁ ′ axis and the O ₂ −O ₂ ′ axis are 90° different from each other, and the O ₁ −O ₁ ′ and O ₂ −O ₂ ′ axes form a pair of two-degree-of-freedom robot joints. are doing.

As mentioned above, if the drive shafts S ₂ and S ₃ are driven in the same direction and at the same angular velocity by the motors M ₂ and M ₃ , the integral bevel gears V ₄₂ and V ₄₃ will be driven by the shafts S ₂ and S _3.
and does not cause any rotation of the frame A ₂ about the axis O ₁ −O ₁ ′.

On the other hand, drive the motor _M1 to drive the bevel gear from the shaft _S1 .
The driving force is transmitted to V ₁₁ , V ₂₁ , and V ₄₁ , and the rotational force of this bevel gear V ₄₁ is also mechanically integrated with the bevel gear V ₄₁ through the shaft 5 . is transmitted to the rotating bevel gear V ₅₁ . Further, as is clear from FIG. 6, the bevel gear _V51 meshes with the bevel gear _V61 , and the bevel gear _V61 meshes with the bevel gear _V81 .

Here, if the bevel gear V ₅₂ driven in the same direction and at the same angular velocity by motors M ₂ and M ₃ and the bevel gear V ₅₁ driven by motor M ₁ rotate at the same angular velocity in opposite directions, then , about the axis O ₂ -O ₂ ', as shown in FIG. 3, the frame A ₃ rotates in the +β or -β direction and functions as a joint.

Conversely, if bevel gears V ₅₂ and V ₅₁ rotate in the same direction and at the same angular velocity, only the shaft S ₇ will rotate and O ₂ −
No rotation about O ₂ ' in the +β or -β direction occurs. In the case of both of these movements, the driving force is
If S ₁ , S ₂ , and S ₃ have the same angular velocity, the load is
It is evenly distributed among M ₁ , M ₂ , and M ₃ .

Therefore, the force transmitted through the two joints O ₁ −O ₁ ′ and O ₂ −O ₂ ′ is only the driving force of the motor M ₁ in the case of FIG. In the case of the figure axis S ₇
The driving force is uniformly supplied from the motors M ₁ , M ₂ , and M ₃ , and a larger driving force is transmitted. Therefore, it is possible to relatively reduce the output of motor _M1 .

Note that the motors M ₂ and M ₃ are centered around the O ₁ −O ₁ ′ axis.
If the frame A ₂ rotates in the +α or −α direction at , the axis S ₇ generally does not need to rotate. However, if shaft S ₁ is fixed and bevel gear V ₁₁ is fixed, bevel gear V ₂₁ is also fixed, so bevel gear V ₄₁ rotates around fixed bevel gear V ₂₁ . In order to
Since V ₄₁ rotates and therefore the shaft S ₇ rotates via the bevel gears V ₅₁ , V ₆₁ , V ₆₂ , the motor
It is necessary to correct the bevel gear V ₂₁ in the opposite direction via the bevel gear V ₁₁ and the shaft S ₁ by the amount that the bevel gear V ₄₁ rotates by driving M ₁ .

In addition, in the above embodiment, the motors M ₁ , M ₂ ,
Although M ₃ is shown in almost the same position, for example motor M ₂
If the system directly drives the bevel gear V ₂₂ without going through the shaft S ₂ and the bevel gear V ₁₂ , or the motor M ₁ directly drives the shaft S ₇ , the motors M ₁ , M ₂ , M The motors M ₁ , M ₂ , shown in the first diagram are larger by reducing the output of ₃ .
The same effect as using M ₃ can be achieved. In particular, it is extremely effective for downsizing the drive motor _M1 of the shaft _S7 .

Effects of the invention As described above, according to the invention, since the free joint parts are driven by multiple motors, the output of each motor can be reduced, and the effect is that it is possible to manufacture a robot with a smaller size. There is.

[Brief explanation of drawings]

Figures 1A and B are explanatory diagrams showing three-dimensional coordinates and joint movements on the same coordinates, Figure 2 is a sectional view of a conventional robot joint, Figure 3 is a sectional view of the same side, and Figure 4. 5 is a right side view of FIG. 4, and FIG. 6 is a partial sectional view of the right side of FIG. 4. M ₁ , M ₂ , M ₃ ... motor, S ₁ , S ₂ , S ₃ ... drive shaft,
A ₁ , A ₂ , A ₃ ... Frame, V ₁₁ , V ₁₂ , V ₁₃ ... Bevel gear.

Claims (1)

[Scope of utility model registration request] A first axis O ₁ -O ₁ ′ that is provided in the first frame A ₁ and constitutes a first joint, and a second axis that is rotatably provided at one end on the axis O ₁ -O ₁ ′. Frame A ₂
and the other end side of the frame A ₂ and the first axis O ₁ −
a second axis O _{2 −O} 2 ′ that is provided in a direction perpendicular to _{O 1} ′ in a plane and constitutes a second joint, and the second axis O ₂
- Third frame A ₃ rotatably provided at O ₂ ′
and bevel gears V ₂₁ , V ₂₂ and V ₃₃ rotatably provided on the first shafts O ₁ -O ₁ ′, respectively, and the bevel gears V ₂₁ , V ₂₂ and V ₃₃ are individually driven. motor
M ₁ , M ₂ and M ₃ , and a bevel provided in the second frame A ₂ in the radial direction of the first axis O ₁ -O ₁ ′ and meshing with the bevel gear V ₂₁ on one end thereof. Gear V ₄₁
a drive shaft S ₅ having a bevel gear V ₅₁ in the opposite direction to V ₄₁ on the other end thereof, and bevel gears V ₂₂ and V ₃₃ rotatably provided on the outer periphery of the drive shaft S ₅ on one end thereof. It has bevel gears V ₄₂ and V ₄₃ on the output side meshing with the
A gear body integrally provided with a bevel gear V ₅₂ in the opposite direction on the other end side, and a gear body rotatably provided on the second shaft O ₂ −O ₂ ′ with the bevel gears V ₅₁ and V ₅₂ . Separately meshing bevel gears V ₆₁ and V ₇₂ and a second shaft O ₂
- a shaft S ₇ protruding from the third frame A 3 in the radial direction of O ₂ ′, and bevel gears V 81 _and V 81 that are provided integrally with the shaft S ₇ and mesh with _the bevel gears V ₆₁ and V ₇₂ ;
A robot joint characterized by having V ₈₂ .