JPS5810490A - Power transmission gear for industrial robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power transmission device for driving the arm, wrist, etc. of an industrial robot.Generally, in industrial robots, it is used to reduce the inertial force of movable parts such as the arm. In addition, a drive device such as a motor is provided on a fixed part or a rotating table, and the arm, wrist, etc. and the drive device are connected by a power transmission device such as a chain or a link mechanism.

FIG. 1 shows an industrial robot using a conventional chain as a power transmission device. A first arm 3 that is swingable about a shaft 2 is provided on the swivel base 1, and a 27th arm 5 that is swingable about a shaft 4 is provided at the upper end of the first arm 3.
is the provision. A wrist 7 rotatable about a shaft 6 is provided at the tip of the 27th arm 5. The first arm 3 and the 27th arm 5 are oscillated by cylinders 8 and 9, respectively. The wrist 7 is driven by a drive device 10 such as a motor via a power transmission device to be described later. The power transmission device is
A sprocket 11 driven directly or indirectly by the drive device 10, a sprocket 12 having the shaft 4 as its central axis, a chain 13 wound between the sprockets 11 and 12, and rotating integrally with the sprocket 12. a sprocket 14 that rotates around the shaft 6 together with the wrist 7, and a tin rocket 14 and 15 that rotates together with the wrist 7.
There is a tension between sprocket 11 and sprocket 12, which has chain 16 wrapped between them.
A tension adjusting device f17 and an idler sprocket 18 are provided, and a tension adjusting device 19 and an idler sprocket 20 are provided between the sprockets 14 and 15.

However, in a power transmission device using a chain as described above, even if the tension of the chains 13 and 16 is increased to the limit by the tension adjustment devices 17 and 19, for example, as shown by the chain line (indicated by the symbol 16'), the chain It is unavoidable that the parts 13 and 16 become sagging, and there is a drawback that backlash occurs between normal rotation and reverse rotation.

Although the sag can be reduced to some extent by using a very large number of idler sprockets 18 and 20,
The problem arises that the weight increases and the price increases.

FIG. 2 shows an industrial robot using a conventional link mechanism as a power transmission device. The shaft 2 is attached to the tip of the first arm 21.
A second arm 23 is provided that is swingable about a shaft 24 as a fulcrum, and a wrist 25 that is swingable about a shaft 24 is provided at the tip of the second arm 23. A lever 26m that can swing around the shaft 22 and a lever 25 that is integrated with the wrist 25.
The lever 2 is connected to the rotor 1 by 27, and the lever 2
The lever 26bK, which is integrated with the lever 26g and which is formed into a parallelogram by the lever 25, the lever 25, the lever 26g, and the lever 26g, is connected to another rod 28, and this rod 28 is not shown in the figure. It is designed to be moved in the axial direction by a separate drive. Therefore, the wrist 25 is
Rod 28, lever 26b, lever 26a, o7 door 27
and is driven via the lever 251.

However, in the power transmission device using the link mechanism as described above, since the wrist 25 is operated by a parallelogram link, the operating range of the wrist 25 is theoretically limited to within 180'. The present invention, which had the disadvantage of being able to operate only about 900 units in practical terms, was developed by focusing on the above 6 problems in conventional industrial robot power transmission devices.
The objective is to obtain a power transmission device for an industrial robot with almost no backlash and a wide operating range.

Hereinafter, the present invention will be explained based on FIGS. 3 to 5 of the accompanying drawings showing embodiments thereof.

An M1 arm 33 that can swing around a shaft 32 as a fulcrum is mounted on a swivel base 31, and a second arm 35 that can swing around a shaft 34 is provided at the upper end of the first arm 33. be. A wrist 37 rotatable about a shaft 36 is installed at the tip of the 27th arm 35. The first arm 33 and the second arm 35 are each swung by a driving device such as a Schilling (not shown). Driven by. The power transmission device includes a sprocket 39 that is directly driven by a drive device 38 and rotates around a shaft 32, a sprocket 40 that rotates around a shaft 34, and a sprocket (described later) that is wound around both sprockets 39 and 40. A transmission member 41, a sprocket 42 that rotates around the shaft 34 together with the sprocket 40, a sprocket 43 that rotates around the shaft 36 together with the wrist 37, and both tin rockets 42 and 43.
The VC winding has a transmission member 44.

The winding transmission member 44 consists of chain parts 44a and 44b that engage with sprockets 42 and 43, respectively, and highly rigid rod parts 44c and 44d that connect both chain parts 44m and 44b. A turnbuckle 44e for tension adjustment is provided on the rad portion 44d. The rod portions 44c and 44d are respectively attached to the second arm 35 and slidably supported by slide bushes 45 and 46, which are wadding guide members. FIG. 5 shows the transmission member 44 in detail. The rod portion 44d has two rods 4 for attaching the turnbuckle 44e.
4d' and 44d#lc are separated, and one end of one rod 44d connects the chain portion 44b and the bottle 44. A male thread is formed at the other end of the rod 44d, which allows a turnbutton 44e to be connected.
is connected to one end of the The rod 44d' is supported by the aforementioned slide bush 46. One end of the rod 44d' (7) on the #J side is connected to the fan section 44a by a pin 44gK, and the other end of the rod 44d' is connected to the pin 44gK. A male thread is formed and is coupled to the other end of the turnbuckle 44e. Turnbuckle 44e
There are nuts on both ends to prevent loosening) 44 h
, l and 44i are provided. Further, the rods 44d' and 44d' are provided with protrusions 44j and 44k for fixing the rods 44d' and 44d' so that they do not rotate when adjusting the turnbuckle 44e. The winding between the sprockets 39 and 40 also applies to the transmission member 41. The winding between the sprockets 39 and 40 has the same structure as the transmission member 44, and consists of chain parts 41a and 41b and 07 dot parts 41c and 41d. A turnbuckle 41e is provided on the portion 41d, and the rod portions 41c and 41d are supported by slide bushes 47 and 48, respectively, which are guide members.

Sprockets) 39, 40, 42, and 43 have a slightly longer length than the entire circumference of the pitch circle, so that each sprocket can be engaged while rotating 360 degrees.

Note that the finger 49 provided at the tip of the wrist 37 is attached to a similar power transmission device fi1 (sprockets 50 and 51, wrapped around the transmission member 52, The drive unit [
54 to rotate about the finger shaft 49m.

The sprocket 53 and the finger shaft 49a have a bevel tooth thickness of 5
5 and 56.

Next, the operation of this power transmission device will be explained.

The rotational force applied to the sprocket 39 by the drive device 38 is transmitted to the sprocket 40 via the chain portion 41a, rod portions 41c and 41d of the transmission member 41, and the chain i%4.1b, and then to the sprocket 40. The Suff'o-cut 4□F, which is integrated with the opening 40, is the transmission part @44f), the x-y part, and the 4-fold.

It is transmitted to the sprocket 43 via the rod portions 44c and 44d and the chain portion 44c. Therefore, the sprocket 43 rotates around the shaft 36.

The wrist 37, which is integral with the sprocket 43, rotates as shown by imaginary lines in FIG. During the above operation, the rod parts 41c, 41d, -44c and 44d are guided by the slide bushes 4748.45 and 46, respectively, and move only in the axial direction, and
Since the rigidity of C and 44d is high, no deflection occurs, and backlash does not occur in these parts.
If 4d is long, the number of slide bushes may be increased.
The length is just enough for 39.40, 42 and 43 to make one rotation, so it is very short, and the deflection in this part is also very small compared to conventional ones. Furthermore, by increasing the tension of the chain parts 411, 41b, 44 and 44b by adjusting the turnbuckles 41e and 44e, the deflection can be further reduced. Therefore, there is almost no backlash in the entire power transmission device, and even if the direction of movement of the wrist 37 is reversed, positional accuracy is maintained at a very high level.

Moreover, since each tin rocket can rotate 360 degrees, there is no limit to the operating range of the hand f37.

The power transmission device that rotates the finger 49 also operates in the same manner as described above.

In addition, although a chain and a sprocket were used in the above embodiment, the same operation and effect can be obtained by using a belt (steel belt, toothed belt, etc.) as the chain portion of the transmission member and replacing the sprocket with a pulley. That is clear. In this case, since the speed of the belt does not change periodically like a chain, more accurate control can be performed.

As explained above, according to the present invention, a driving wheel (sprocket, pulley) is attached to one shaft on the arm of an industrial i-bot, and a driven wheel (sprocket, pulley) is attached to the other shaft, and the driving wheel is wrapped around the driving wheel. A winding part (chain part, belt part) that can be freely bent, and a part (chain part, belt part) that can be freely bent and wrapped around a driven wheel.
Both windings have a pair of rigid rod parts connected between the ends of the parts. The winding winds the transmission member between the driving wheel and the driven wheel, and supports the rigid rod part so as to be movable in the axial direction. Since the guide member (slide bush in the embodiment) is 8'lft, it is possible to perform highly accurate movement with almost no backlash, and there is also an effect that there is no restriction on the movement range. In addition, the power transmission device according to the present invention can be idled, reducing the inertial force of the arm, and since the rod portion of the transmission member receives only tensile force, it is necessary to consider buckling load. It can be made thinner and lighter.

[Brief explanation of the drawing]

1 is a diagram showing a conventional chain type power transmission device, FIG. 2 is a diagram showing a conventional link type power transmission device, FIG. 3 is a front view of the power transmission device according to the present invention, and FIG. 4 is a diagram showing a conventional link type power transmission device. 3 is a sectional view taken along the line IV-■ of the power transmission device, and FIG. 5 is a diagram showing details of the winding transmission member. 33...first arm, 35...second arm, 37.
... Wrist, 38... Drive device, 39.40... Sprocket, 41... Wrap is transmission member, 41a, 41b
...Chain W, 41c, 41d...Rod part, 4
1 e... turnbuckle, 42, 43... sprocket, 44... winding is transmission member, 44a, 44b...
...Chain part, 44C, 44d...Set part, 44
C... Turnbuckle, 45, 46... Slide bush.

Claims (1)

[Claims] 1. In a power transmission device that transmits rotational driving force of one shaft on an arm of an industrial gutter to another shaft on the arm, a driving wheel is attached to one shaft and the other shaft is driven. A first flexible winding part that is attached to the vehicle and wound around the driving vehicle is a part, a second flexible winding part that is wound around the driven vehicle is a part,
The first winding has a pair of rigid rod parts connecting one end and the other end of the part to one end and the other end of the second winding, respectively. A power transmission device for an industrial gutter, which is characterized by being provided with a guide member that is wound around the shaft and movably supports the rigid rond part in the axial direction. 2. The power transmission device for an industrial loget according to claim 1, wherein the motive wheel and the driven wheel are sprockets, and the first and 20th windings are chains. 3. The M moving vehicle and the driven vehicle are pulleys, and the first and second
2. The power transmission device for an industrial robot according to claim 1, wherein the winding part is a belt.