Patent ID: 12188611

DETAILED DESCRIPTION OF EMBODIMENTS

A lubricant bath structure1and a robot100according to a first embodiment of the present disclosure will now be described with reference to the drawings.

As illustrated inFIG.1, for example, the robot100of this embodiment is a 6-axis articulated robot.

The robot100includes a base30fixed to a horizontal placement surface20aof a support table20installed onto a horizontal floor, and a swing barrel (casing)40supported by one side surface of the base30so as to be rotatable about a horizontal first axis A. The robot100includes a first arm (arm member)50that is supported so as to be rotatable with respect to the swing barrel40about a second axis (axis) B that lies in a flat plane orthogonal to the first axis A. The robot100also includes a second arm60supported so as to be linearly movable in the longitudinal direction of the first arm50, and a 3-axis wrist unit70disposed at a tip of the second arm60.

A lubricant bath structure1of this embodiment is provided in, for example, a joint mechanism10between the swing barrel40and the first arm50.

As illustrated inFIGS.2and3, the joint mechanism10includes a servomotor (mechanism part)2that drives the first arm50to rotate about the second axis B with respect to the swing barrel40, and a reducer3.

The swing barrel40includes a bracket (casing body)41constituting one part of the swing barrel40, and a lid member (casing)42detachably attached to the bracket41. The bracket41has a hollow part41athat penetrates in the direction along the second axis B and that has a circular cross sectional shape, the lid member42is attached to one end side of the hollow part41ain the second axis B direction, and the reducer3is attached to the other end side.

Multiple screw holes41bequally spaced from one another in the circumferential direction are formed in the outer periphery of the hollow part41aon one end side of the bracket41.

The lid member42is formed into a circulate plate shape that can close the one end side of the hollow part41a, and has a fitting part42athat fits into the hollow part41a, and multiple through holes42bthat can be arranged at positions coincident with the screw holes41bin the bracket41when the fitting part42ais fitted into the hollow part41a.

In a state where the fitting part42ais fitted into the hollow part41a, bolts7penetrating through the through holes42bare fastened into the screw holes41b, and, as a result, the lid member42can be fixed to the bracket41in a positioned state, and one end side of the hollow part41acan be closed. A seal member (not illustrated) such as an O ring is disposed between the lid member42and the bracket41to provide a tight seal.

In a state where all bolts7are removed, the lid member42can rotate about the second axis B with respect to the bracket41. According to this feature, the angle at which the lid member42is installed with respect to the bracket41can be adjusted in increments of the angle between the screw holes41badjacent in the circumferential direction of the bracket41, for example, 30°, in the example illustrated inFIG.2. Moreover, the lid member42can be easily detached from the bracket41by removing all of the bolts7.

The bracket41has a fitting part41cinto which a fixing part3aof the reducer3is fitted, and through holes41dthrough which bolts8that fix the fixing part3aof the reducer3onto the bracket41penetrate. The space between the fixing part3aof the reducer3and the bracket41is also tightly sealed with a seal member (not illustrated) such as an O ring. An output part3bof the reducer3is fixed to the first arm50. The space between the output part3band the first arm50is also tightly sealed with a seal member (not illustrated) such as an O ring.

The reducer3includes a center gear3csupported so as to be rotatable about the second axis B. The reducer3reduces the rotation of a shaft (motor shaft)2aof the servomotor2, transmits the rotation to the first arm50, and drives the first arm50to rotate about the second axis B with respect to the swing barrel40.

The lid member42has a supply hole11, a discharge hole12, a liquid level check hole13, and a part attachment hole14that penetrate through in the thickness direction.

The supply hole11, the discharge hole12, and the liquid level check hole13each have a bore sufficiently smaller than the part attachment hole14.

The supply hole11is a hole for injecting a lubricant5into a lubrication space4described below, the discharge hole12is a hole for discharging the lubricant5in the lubrication space4to outside, and the part attachment hole14is a hole for attaching the servomotor2. The liquid level check hole13is a hole for checking the liquid level of the lubricant5in the lubrication space4when detaching the servomotor2from the part attachment hole14.

The supply hole11and the discharge hole12have female screws formed in their inner peripheral surfaces, and can be opened and closed by respective plugs11aand12athat are detachably fastened to the female screws. In the same manner, the liquid level check hole13also has a female screw formed in its inner peripheral surface, and can be opened and closed by a plug (stopper)13adetachably fastened to the female screw.

The part attachment hole14has a recess14ainto which a spigot joint portion2cof the servomotor2is fitted, and this recess14ais formed in the outer periphery of an end portion (outside surface)42cthat will be situated on the outer side when the lid member42is attached to the bracket41. The part attachment hole14has an inner diameter at least sufficient for inserting the input gear2bfixed to the shaft2aof the servomotor2. The space between the servomotor2and the lid member42is also tightly sealed with a seal member (not illustrated) such as an O ring.

As illustrated inFIG.3, in the lubricant bath structure1, the lid member42is fixed to one end side of the hollow part41aof the bracket41, the servomotor2is attached to the part attachment hole14, and the supply hole11, the discharge hole12, and the liquid level check hole13are closed by the plugs11a,12a, and13a. In this manner, the lubrication space4tightly sealed by being surrounded by the lid member42, the bracket41, the reducer3, and the first arm50is formed.

The lubrication space4stores a required amount of the liquid lubricant5, such as oil, for lubricating the mechanism parts of the reducer3including the input gear2band the center gear3c.

As illustrated inFIG.4, in a state where the second axis B lies horizontally, the lid member42is fixed to the bracket41at such an attachment angle about the second axis B that the part attachment hole14is situated above the second axis B. Here, the supply hole11is situated above the liquid level of the required amount of lubricant5stored in the lubrication space4. Furthermore, in this state, the discharge hole12is arranged in the vicinity of the bottom of the lubrication space4, and the liquid level check hole13is arranged at a position coincident with or lower than the lower edge of the part attachment hole14and higher than the discharge hole12.

Here, that the liquid level check hole13is at a position coincident with or lower than the lower edge of the part attachment hole14means that, as illustrated inFIG.4, in a state where the second axis B lies horizontally, the liquid level check hole13is arranged at a position at which a horizontal line H in contact with the lowest edge of the part attachment hole14contacts the lowest edge of the liquid level check hole13, or at a position lower than this position.

The operation of the lubricant bath structure1and the robot100according to this embodiment having the aforementioned features will now be described.

When maintenance operation of the servomotor2of the robot100of this embodiment is to be conducted, first, the swing barrel40of the robot100is rotated about the first axis A with respect to the base30so that, as illustrated inFIG.1, the swing barrel40assumes a posture with which the second axis B is horizontal. In addition, the first arm50is pressed against a stopper (not illustrated) to assume a posture with which the first arm50does not fall off by detaching the servomotor2, or is suspended by using a crane or the like.

Next, before detaching the servomotor2from the lid member42, the plugs11aand13afastened to the supply hole11and the liquid level check hole13are unfastened. In such a case, since the supply hole11is arranged above the liquid level of the lubricant5in the lubrication space4, the supply hole11functions as a vent hole that takes outside air into the lubrication space4once the plug11ais unfastened.

When the plugs11aand13aare unfastened, the outside air is taken into the lubrication space4through the supply hole11, and the lubricant5in the lubrication space4is gravitationally discharged to outside through the liquid level check hole13. When the liquid level of the lubricant5in the lubrication space4reaches the height position of the lower edge of the liquid level check hole13, discharge of the lubricant5through the liquid level check hole13stops. As a result, the liquid level of the lubricant5in the lubrication space4is coincident with or lower than the lower edge of the part attachment hole14.

In other words, an operator can easily check that the liquid level of the lubricant5in the lubrication space4has reached the lower edge of the part attachment hole14or a position lower than the lower edge by confirming whether discharge of the lubricant5through the liquid level check hole13has stopped. In addition, since the liquid level check hole13has a diameter sufficiently smaller than that of the part attachment hole14, the lubricant5can be prevented from flowing out all at once.

Subsequently, the operator detaches the servomotor2to be maintained from the lid member42.

Detaching the servomotor2leaves the part attachment hole14open; however, since the lubricant5in the lubrication space4is at the lower edge of the part attachment hole14or at a position lower than this, the lubricant5is prevented from flowing out through the part attachment hole14.

Next, a repaired servomotor2or a new servomotor2is attached to the lid member42to close the part attachment hole14. In addition, the plug13ais fastened into the liquid level check hole13to close the liquid level check hole13. A nipple for supplying oil is attached to the supply hole11, and the lubricant5is charged into the lubrication space4by using an oil supply device such as an oil gun until the liquid level of the required amount is reached. This completes the maintenance operation of the servomotor2. The amount of the lubricant5required for the liquid level to reach the liquid level of the required amount from the state where the liquid level is at the position of the liquid level check hole13is predetermined, and thus the lubricant5can be accurately charged until the liquid level of the required amount is reached by administering the supply amount through the supply hole.

As such, according to this embodiment, prior to detaching the servomotor2, the lubricant5is discharged through the liquid level check hole13, and thus, the liquid level of the lubricant5in the lubrication space4can be reliably arranged to come at the lower edge of the part attachment hole14or a position lower than this. As a result, when the servomotor2is detached from the part attachment hole14, the lubricant5in the lubrication space4can be prevented from vigorously jetting out through the part attachment hole14to the outside. In particular, in the case of a large robot, the capacity of the lubrication space4is large, and thus it is effective to suppress the amount of discharge of the lubricant5for the maintenance. This not only reduces the amount of the lubricant5discarded but also dramatically shortens the time required for the maintenance operation by shortening the time required for discharging and charging.

Instead of discharging the lubricant5through the liquid level check hole13, the lubricant5can be discharged through the discharge hole12. However, the amount of discharge increases if all of the lubricant5in the lubrication space4is to be discharged through the discharge hole12. Moreover, although it is possible to reduce the amount of discharge by interrupting the discharge through the discharge hole12, the liquid level of the lubricant5can only be an estimate in such a case, and it is difficult to minimize the amount of discharge.

Accordingly, this embodiment provides an advantage in that the amount of lubricant5discharged for the maintenance of the servomotor2can be reliably kept to a requisite minimum, thereby shortening the time required to discharge and charge the lubricant5, and that the operation efficiency of the maintenance operation can be improved.

Furthermore, according to this embodiment, after the plug13athat has been closing the liquid level check hole13is unfastened, the liquid level can be left unattended until discharge of the lubricant5through the liquid level check hole13stops. In other words, the operator does not have to monitor the liquid level during discharge of the lubricant5and can attend to other tasks during the stand-by time while still preventing excessive discharge of the lubricant5. As a result, the operation efficiency can be improved.

In this embodiment, in a state where the second axis B is arranged horizontally, the part attachment hole14is arranged to be above the second axis B so that the part attachment hole14can be arranged at a position as close to the liquid level of the required amount of the lubricant5as possible. This offers an advantage in that the amount of the lubricant5discharged from the lubrication space4for maintenance of the servomotor2can be further reduced.

In this embodiment, as described above, the cross-sectional shape of the hollow part41ais circular, and the screw holes41band the through holes42bare formed in the bracket41and the lid member42so that the holes are spaced by 30° in the circumferential direction about the second axis B. As a result, the attachment angle of the lid member42can be adjusted in increments of 30° about the second axis B.

For example, as illustrated inFIG.5, when the placement surface20aof the support table20where the robot100is placed is sloping 30° with respect to the horizontal direction, the attachment angle of the lid member42to the bracket41can be adjusted such that the discharge hole12is at the lowest position. In other words, even when the angle of the placement surface20aof the support table20is changed, the relative positional relationship in the gravitational direction among the supply hole11, the discharge hole12, the liquid level check hole13, and the part attachment hole14formed in the lid member42can be maintained.

The intervals of the screw holes41band the through holes42bare not limited to 30° and may be any desired angle. The attachment position can be more finely adjusted by forming the screw holes41band the through holes42bwith smaller interval angles. Moreover, the through holes42bmay be formed as arc-shaped long holes extending in the circumferential direction about the second axis B so that the attachment position can be adjusted steplessly.

Moreover, in this embodiment, an example in which there is a single part attachment hole14used to attach one servomotor2is described; alternatively, there may be multiple part attachment holes14and multiple servomotors2.

In such a case, one liquid level check hole13may be provided for each part attachment hole14, or, when the lower edges of the part attachment holes14are at the same position, a common liquid level check hole13may be provided for the multiple part attachment holes14.

In this manner, when conducting maintenance of any one of servomotors2, the lubricant5can be discharged by utilizing the liquid level check hole13arranged at the height position of the lower edge of the part attachment hole14corresponding to the servomotor2to be maintained.

In other words, when the joint mechanism10includes multiple part attachment holes14and multiple servomotors2, the amount of the lubricant5discharged for the maintenance operation of the servomotor2can be reduced to the requisite minimum depending on the servomotor2to be maintained.

In this embodiment, the servomotor2is described as an example of the mechanism part that opens and closes the part attachment hole14by being attached or detached; however, the mechanism part is not limited thereto. For example, the mechanism part may be any desired mechanism part that can be detachably attached to the lid member42, such as an oil temperature sensor, an oil pressure sensor, or an oil filter.

Although an example in which the lubricant bath structure1is provided in the joint mechanism10between the swing barrel40and the first arm50of the robot100is described, the lubricant bath structure1is not limited thereto and may be applied to a joint mechanism at any desired position, for example.

Moreover, in this embodiment, a 6-axis articulated robot is described as an example of the robot100; however, the robot is not limited thereto and may be any robot that has at least one joint mechanism. Furthermore, the lubricant bath structure1may be employed in any device other than a robot.

Furthermore, an example in which the supply hole11, the discharge hole12, the liquid level check hole13, and the part attachment hole14are all formed in the lid member42that forms the lubrication space4, and in which the lid member42is fixed to the bracket41of the swing barrel40has been described. According to this, the lid member42is maintained at the same position even when the first arm50is actuated, and thus, for maintenance of the servomotor2, it is only necessary to have the second axis B arranged horizontally to prevent falling of the first arm50.

Alternatively, at least one of the supply hole11, the discharge hole12, the liquid level check hole13, and the part attachment hole14may be formed in some other member that constitutes the lubrication space4, for example, the reducer3or the first arm50.

Next, a lubricant bath structure1′ and a robot100′ according to a second embodiment of the present disclosure are described with reference to the drawings.

In the description of this embodiment, the features that are common to the lubricant bath structure1and the robot100of the first embodiment described above are denoted by the same reference signs and the descriptions therefor are omitted.

As illustrated inFIG.6, a lid member42′ of the lubricant bath structure1′ of this embodiment has a liquid level check hole13′ that is closed by a window member13bformed of an optically transparent resin, glass, or the like instead of a liquid level check hole13′ that can be opened and closed with the plug13a.

The window member13bis fixed in the liquid level check hole13′ in a state where the space between the window member13band the inner surface of the liquid level check hole13′ is tightly sealed with rubber or an adhesive. Moreover, the window member13bincludes a mark (indicator)13cat a position coincident with the height of the lower edge of the part attachment hole14.

According to the lubricant bath structure1′ and the robot100′ of this embodiment having such features, before detaching the servomotor2from the lid member42′, the plugs11aand12aare removed from the supply hole11and the discharge hole12to open the supply hole11and the discharge hole12. As a result, while the outside air is taken into the lubrication space4through the supply hole11, the lubricant5in the lubrication space4is gravitationally discharged to outside through the discharge hole12arranged in the vicinity of the bottom of the lubrication space4.

In such a case, the operator can check the liquid level of the lubricant5in the lubrication space4by observing the inside of the lubrication space4from outside through the window member13b. Then when the liquid level of the lubricant5in the lubrication space4has become coincident with the mark13cin the window member13b, the discharge hole12is shut with the plug12a.

As a result, the lubricant5in the lubrication space4can be discharged until the liquid level reaches the height position of the lower edge of the part attachment hole14.

Furthermore, the lubricant5in the lubrication space4can be discharged through the discharge hole12arranged at a position closer to the floor. This provides an advantage in that, when the discharged lubricant5is recovered by allowing the discharged lubricant5to drop onto a tray or the like placed on the floor, the dropping distance of the lubricant5can be shortened and scattering of the lubricant5over the floor, etc., can be suppressed.

Here, the discharge hole12used to discharge the lubricant5in such a case is also used to discharge the lubricant5for maintenance operation other than the maintenance operation of the servomotor2, such as replacing the lubricant5in the lubrication space4with a new lubricant5. This provides an advantage in that the discharge position of the lubricant5does not have to change depending on the content of the maintenance operation.

In the case of the liquid level check hole13′ with the window member13bfitted therein, the lubricant5is not discharged through the liquid level check hole13; thus, the liquid level check hole13′ itself may be formed to be larger than the discharge hole12to improve the visibility of the liquid level inside.

Instead of having the window member13bfitted in the liquid level check hole13′ having a circular cross-sectional shape, the liquid level check hole13′ may be formed to have a long hole shape extending in the vertical direction. This provides an advantage in that the change in liquid level inside the lubrication space4can be more reliably checked during discharge of the lubricant5.

Although the mark13cis provided in the window member13b, the mark13cmay be omitted. Instead of checking the liquid level inside through a transparent window member13b, a sensor may be used to detect that the liquid level inside has reached below the lower edge of the part attachment hole14, and this may be alarmed through a lamp, a buzzer, or the like. In detecting the liquid level with a sensor, a valve that can be shut in response to the detection signal from the sensor may be provided in the discharge hole.