JP2023083666A - Grease replacing method and confirming method for grease replacing degree - Google Patents

Abstract

To increase the grease replacing rate.SOLUTION: A grease replacing method in a speed reducer 4 having a casing 41 which stores a gear and in which a prescribed amount of grease is enclosed comprises: performing a replacing operation for discharging the grease from the casing 41 and injecting new grease into the casing 41 until the amount of grease in the casing becomes greater than the prescribed amount; performing a gear rotating operation after the replacing operation; and, after the gear rotating operation, performing an amount adjusting operation for discharging the grease from the casing 41 until the amount of grease in the casing 41 becomes the prescribed amount.SELECTED DRAWING: Figure 2

Description

The technology disclosed herein relates to a grease replacement method and a method for confirming the degree of grease replacement.

Grease for lubrication is enclosed in gear devices such as reduction gears provided in robots, machine tools, and the like, and the grease deteriorates according to operating conditions and must be replaced as appropriate. For example, in the replacement method disclosed in Patent Document 1, new grease is injected from a grease supply port of the gear case, and old grease is pushed out from the grease discharge port of the gear case. Then, when the color of the grease pushed out from the grease discharge port changes to the color of the new grease, the injection of the new grease is stopped, and the grease exchange is completed.

JP 2005-177914 A

However, in the grease replacement method of Patent Literature 1, old grease is only pushed out with new grease, and the old grease in the speed reducer cannot be sufficiently replaced, and the grease replacement rate is not sufficient.

The technique disclosed here has been made in view of this point, and its purpose is to improve the grease exchange rate.

The technique disclosed herein is a grease replacement method in a gear device having a casing in which gears are accommodated and a specified amount of grease is enclosed. This grease replacement method includes performing a replacement operation of discharging grease from the casing and injecting new grease into the casing until the amount of grease in the casing exceeds the specified amount; After the operation, rotating the gear; and after rotating the gear, adjusting the amount of grease discharged from the casing until the amount of grease in the casing reaches the specified amount. include.

According to the above-described grease replacement method, the grease replacement rate can be improved.

FIG. 1 is a block diagram showing a schematic configuration of a robot. FIG. 2 is a flow chart showing the grease replacement method. FIG. 3 is a schematic diagram showing one state when the grease of the speed reducer is replaced. FIG. 4 is a schematic diagram showing one state when the grease of the speed reducer is replaced. FIG. 5 is a schematic diagram showing one state when the grease of the speed reducer is replaced. FIG. 6 is a schematic diagram showing one state when the grease of the speed reducer is replaced. FIG. 7 is a schematic diagram showing one state when the grease of the speed reducer is replaced. FIG. 8 is a schematic diagram showing one state when the grease of the speed reducer is replaced. FIG. 9 is a graph for explaining an example of prediction of the first grease replacement date. FIG. 10 is a graph for explaining an example of prediction of the first grease replacement date. FIG. 11 is a graph for explaining an example of predicting the second and subsequent grease replacement dates. FIG. 12 is a schematic diagram showing one state when the grease of the speed reducer is replaced. FIG. 13 is a schematic diagram showing one state when the grease of the speed reducer is replaced. FIG. 14 is a schematic diagram showing one state when the grease of the speed reducer is replaced. FIG. 15 is a schematic diagram showing one state when the grease of the speed reducer is replaced.

Exemplary embodiments are described in detail below on the basis of the drawings. FIG. 1 is a block diagram showing a schematic configuration of a robot.

The grease replacement method of the present embodiment is a grease replacement method for a speed reducer 4 having a casing 41 in which gears are accommodated and a specified amount of grease is enclosed. The speed reducer 4 is an example of a gear device. In this example, the speed reducer 4 is intended for use in an industrial robot 100 .

For example, the robot 100 comprises a base 1 and a robot arm 2 connected to the base 1 . The robot arm 2 has a plurality of links rotatably connected to each other. A proximal end of the robot arm 2 is rotatably connected to the base 1 . A hand (not shown) is rotatably connected to the tip of the robot arm 2 . The robot 100 further comprises a motor 3 and a reducer 4 that drive the robot arm 2, for example. A motor 3 is connected to the robot arm 2 via a speed reducer 4 . That is, the speed reducer 4 transmits the rotational power of the motor 3 to the robot arm 2 .

FIG. 3 is a schematic diagram showing one state when the grease of the speed reducer 4 is replaced. As shown in FIG. 3 , the speed reducer 4 has a closed casing 41 . Gears are housed in the casing 41, and more specifically, a gear train 45 is housed therein. The gear train 45 is formed by a plurality of gears meshing with each other. The casing 41 also contains a specified amount of grease (old grease Go) for lubricating the gear train 45 and bearings (not shown). Grease is a highly viscous semi-solid (so-called gel) lubricant.

The above-mentioned specified amount means that when the gear train 45 is operated (that is, rotates) by the motor 3 in the closed casing 41, the pressure inside the casing 41 is prevented from rising abnormally, and the gear train 45 and the like are prevented from increasing. It is an amount that can sufficiently ensure lubrication. For example, when the casing 41 is filled with a larger amount of grease than the specified amount and the speed reducer 4 is operated, the pressure inside the casing 41 rises abnormally, and the various sealing members provided inside the casing 1 are exposed to the abnormal pressure. may be damaged by Further, if the casing 41 is filled with grease in an amount smaller than the specified amount and the speed reducer 4 continues to operate, an abnormal increase in the pressure inside the casing 41 can be prevented, but lubrication of the gear train 45 and the like may be insufficient. turn into.

A casing 41 of the speed reducer 4 is formed with two through-holes (that is, a first through-hole 42 and a second through-hole 43) for supplying and discharging grease. Specifically, the first through hole 42 is formed in the lower portion of the casing 41 and the second through hole 43 is formed in the upper portion of the casing 41 . More specifically, the first through hole 42 is formed in the lowermost portion of the casing 41 and the second through hole 43 is formed in the uppermost portion of the casing 41 . Both the first through hole 42 and the second through hole 43 are openable and closable through holes.

Further, the casing 41 of the speed reducer 4 has a portion 44 where grease is difficult to discharge. The difficult-to-discharge portion 44 is a region within the casing 41 in which it is difficult to replace the grease due to the structure and arrangement of the gear train 45 and the like, that is, a region in which it is difficult to discharge the grease from the outside of the casing 41 .

FIG. 2 is a flow chart showing the grease replacement method. Each of FIGS. 4 to 8 is a schematic diagram showing one state when the grease of the speed reducer 4 is replaced. A method for exchanging grease in the speed reducer 4 is performed based on the flowchart of FIG. The grease replacement method of this example includes performing a replacement operation, rotating a gear, and performing an amount adjusting operation. Furthermore, the grease replacement method of this example includes performing an operation of confirming the degree of grease replacement and performing an operation of predicting the replacement timing.

The replacement operation is performed by steps S1 to S3. In the replacement operation, first, a grease discharging operation is performed (step S1). This discharging operation is an operation for discharging old grease (hereinafter also referred to as old grease Go) from the casing 41 . Specifically, as shown in FIG. 3, the speed reducer 4 before the discharge operation is in a state in which a specified amount of grease (that is, old grease Go) is enclosed in the casing 41 . More specifically, in the casing 41, a specified amount of grease is enclosed by enclosing the grease up to a specified height H. In this state, the first through-hole 42 and the second through-hole 43 are closed.

As shown in FIG. 4, the first through-hole 42 and the second through-hole 43 are opened during the grease discharging operation. That is, the inside of the casing 41 is open to the outside air. Then, the old grease Go inside the casing 41 is discharged from the first through hole 42 . In this example, although not shown, the old grease Go is discharged from the casing 41 by sucking the old grease Go with a suction cylinder. Further, in this discharging operation, since the second through hole 43 is open, as the old grease Go is discharged from the first through hole 42, outside air is taken into the casing 41 through the second through hole 43. . Therefore, it is possible to prevent the inside of the casing 41 from becoming in a negative pressure state, so that the old grease Go is smoothly discharged from the casing 41 .

On the other hand, in this discharging operation, the old grease Go existing in the difficult-to-discharge portion 44 of the casing 41 remains without being discharged. In other words, in this discharging operation, the old grease Go in the area other than the difficult-to-discharge portion 44 inside the casing 41 is discharged from the casing 41 .

In the subsequent step S2, the connecting operation of the auxiliary container 47 is performed. This connecting operation is, as shown in FIG. The auxiliary container 47 is formed, for example, in the shape of a bottomed cylinder with one end closed, and the closed end is connected to the second through hole 43 . The auxiliary container 47 and the second through hole 43 are connected by screwing, for example. Thus, the inside of the casing 41 and the inside of the auxiliary container 47 communicate with each other via the second through hole 43 . That is, the inside of the casing 41 is open to the outside air via the second through hole 43 and the auxiliary container 47 .

In subsequent step S3, a grease injection operation is performed. This injection operation is an operation of injecting new grease (hereinafter also referred to as new grease Gn) into the casing 41 until the amount of grease in the casing 41 exceeds the above-described specified amount. Specifically, as shown in FIG. 6, new grease Gn is injected into the casing 41 through the first through holes 42 . At this time, the new grease Gn is injected into the casing 41 until the grease in the casing 41 (in this example, the new grease Gn) exceeds the specified height H. Therefore, the amount of new grease Gn to be injected into the casing 41 is increased compared to the case where the new grease Gn is injected until the grease in the casing 41 reaches the specified height H, for example.

More specifically, the new grease Gn is injected until the grease in the casing 41 enters the auxiliary container 47 through the second through hole 43 . Therefore, the grease in the casing 41 can be easily filled up without spilling the new grease Gn from the casing 41 onto the floor or the like. That is, when the new grease Gn enters the auxiliary container 47 from the second through hole 43, it can be understood that the grease in the casing 41 is full. By injecting the new grease Gn until the grease in the casing 41 is filled up in this way, the amount of the new grease Gn injected into the casing 41 is maximized.

In this injection operation, since the inside of the casing 41 is open to the outside air via the second through-hole 43 and the auxiliary container 47, the new grease Gn is injected from the first through-hole 42, and the casing 41 is The air inside is discharged from the auxiliary container 47 . Therefore, the new grease Gn can be smoothly injected into the casing 41 .

In this manner, the replacement operation is to discharge the old grease Go from the casing 41 and to inject the new grease Gn into the casing 41 until the amount of grease in the casing 41 exceeds the specified amount. This is an operation to replace with new grease Gn. More specifically, in the replacement operation, after the old grease Go is discharged from the casing 41 , new grease Gn is injected into the casing 41 through the first through holes 42 . In the replacement operation, when the new grease Gn is injected from the first through hole 42 , the auxiliary container 47 that can be opened to the outside air is connected to the second through hole 43 .

In the subsequent step S4, the gear is rotated. The rotation operation of the gears is the operation of actuating the gear train 45 after the switching operation, that is, rotating each gear of the gear train 45 . Specifically, the gear train 45 is operated by the motor 3 . Inside the casing 41, the grease is agitated by the operation of the gear train 45. As shown in FIG. As a result, as shown in FIG. 7, the new grease Gn and the old grease Go present in the difficult-to-discharge portion 44 are mixed within the casing 41 . The grease obtained by mixing the new grease Gn and the old grease Go in this manner is hereinafter also referred to as mixed grease Gm.

When the gear rotates, the casing 41 is exposed to the outside air. That is, the gear train 45 is operated while the inside of the casing 41 is open to the outside air. Specifically, the inside of the casing 41 is open to the outside air via the second through hole 43 and the auxiliary container 47 . Note that the first through hole 42 is closed in this example. In this way, since the gear train 45 is operated while the inside of the casing 41 is open to the outside air, the pressure inside the casing 41 is prevented from abnormally rising.

In subsequent step S5, an operation for adjusting the amount of grease is performed. This amount adjustment operation is an operation for discharging grease from the casing 41 until the amount of grease in the casing 41 reaches a specified amount after the gear rotation operation.

Specifically, the amount adjusting operation in this example is performed while the auxiliary container 47 is connected to the casing 41 . Immediately after the gear rotates, the inside of the casing 41 is filled with the mixed grease Gm (see FIG. 7). That is, the mixed grease Gm in the casing 41 is larger than the specified amount. Further, since the second through-hole 43 is open through the auxiliary container 47, the inside of the casing 41 is open to the outside air.

In this amount adjusting operation, the mixed grease Gm in the casing 41 and the auxiliary container 47 is discharged from the first through hole 42, as shown in FIG. At this time, the mixed grease Gm is discharged from the casing 41 until the mixed grease Gm in the casing 41 reaches the specified height H. In this example, although not shown, the mixed grease Gm is discharged from the casing 41 by sucking the mixed grease Gm with a suction cylinder. Further, as the mixed grease Gm is discharged from the first through-hole 42 , outside air is drawn into the casing 41 through the second through-hole 43 , so the mixed grease Gm is smoothly discharged from the casing 41 . When the mixed grease Gm in the casing 41 reaches the specified height H, the amount adjusting operation is finished, and then the auxiliary container 47 is removed from the casing 41 . At this time, since no grease (that is, mixed grease Gm) exists in the auxiliary container 47, the auxiliary container 47 can be removed without spilling the grease.

In this manner, in the amount adjustment operation, the mixed grease Gm obtained by mixing the old grease Go and the new grease Gn in the difficult-to-discharge portion 44 is discharged until the specified amount is reached. Therefore, the ratio of the new grease Gn contained in the specified amount of grease in the casing 41 increases. That is, by discharging the mixed grease Gm, part of the old grease Go in the difficult-to-discharge portion 44 is discharged. higher percentage. Therefore, the grease exchange rate R, which will be described later, is improved. If the gear rotation is not performed, the old grease Go and the new grease Gn in the difficult-to-discharge portion 44 are not mixed, so the grease discharged by the amount adjustment operation is substantially only the new grease Gn. Therefore, the ratio of the new grease Gn contained in the specified amount of grease does not increase.

In the subsequent step S6, an operation for confirming the degree of grease replacement is performed. This confirmation operation is based on the additive consumption rate P1 of the old grease Go in the casing 41 before the replacement operation and the additive consumption rate P2 of the mixed grease Gm in the casing 41 after the amount adjustment operation. This is an operation of obtaining the grease exchange rate R by using the sprocket and confirming the degree of grease exchange.

The degree of grease replacement is the ratio of the amount of new grease Gn replaced with the specified amount of old grease Go. The grease exchange rate R is an index that specifically expresses the degree of grease exchange. That is, by obtaining this grease replacement rate R, it is possible to confirm the effectiveness of the grease replacement performed in steps S1 to S5. That is, the higher the grease replacement rate R, the more the amount of new grease Gn replaced, and the more effective the grease replacement. Specifically, the grease exchange rate R is obtained by the following formula 1. In this example, the unit of the grease exchange rate R is %.
Formula 1: R = ((P1-P2)/P1) x 100

Grease contains a certain amount of additives. In this example, phosphorus compounds and compounds containing phosphorus-sulfur double bond groups are included as additives (specifically, extreme pressure additives and friction modifiers). Grease additives often used in the speed reducer 4 of the robot 100 include, for example, ZnDTP (zinc dialkyldithiophosphate) and MoDTP (molybdenum dialkyldithiophosphate). This point is the same for the grease used for the speed reducer of the machine tool. There are various analytical methods and analytical instruments, and one example is spectroscopic analysis using Fourier Transform Infrared Spectroscopy (FT-IR) as a quantitative analysis method for phosphorus-sulfur double bond groups. .

The additives in the grease are gradually oxidized and consumed by the operation of the speed reducer 4 . The consumption rate of the additive described above is the ratio of the amount of the additive consumed to the content of the additive in the grease at the time of shipment of the speed reducer 4 (robot 100). The higher the consumption rate of the additive, the lower the performance of the grease, that is, the worse the grease. The additive consumption rate P1 is measured by sampling a portion of the old grease Go of the speed reducer 4 in the state shown in FIG. 3, for example, before the replacement operation. The additive consumption rate P2 is measured by sampling a portion of the mixed grease Gm of the speed reducer 4 in the state shown in FIG. 8 after the amount adjustment operation. Naturally, the consumption rate P1 is higher than the consumption rate P2.

As described above, the consumption rate of the additive is a value corresponding to the deterioration of the grease, so it can be said that it is a parameter that appropriately reflects the difference between the old grease Go and the new grease Gn. Therefore, the grease exchange rate R obtained based on the consumption rate of such additives is an index that appropriately reflects the degree of grease exchange.

In the subsequent step S7, an operation for predicting the timing of grease replacement is performed. In this prediction operation, the first grease replacement timing (hereinafter also referred to as the grease replacement date) is predicted from the operation start date (i.e., delivery date) of the speed reducer 4, and the second and subsequent grease replacement timings are predicted. actions are performed. Hereinafter, the operation start date of the speed reducer 4 is also simply referred to as "operation start date".

The operation of predicting the timing of the first grease replacement will be described. 9 and 10 are graphs for explaining an example of prediction of the first grease replacement date. In this example, when the consumption rate of the additive in the grease in the casing 41 reaches a predetermined control reference value, it is time to replace the grease.

First, when the operation start date of the speed reducer 4 is known, the date of the first grease replacement is predicted as follows. As shown in FIG. 9, based on the slope of a straight line passing through the additive consumption rate P0 (generally 0%) on the start date of operation and the additive consumption rate P01 on an arbitrary day, the additive A prediction time t1 is predicted until the day when the consumption rate reaches the management reference value (indicated by the consumption rate P1 in FIG. 9). In this example, correction is required when the additive consumption rate P0 on the operation start date is not zero, but the explanation of this correction is omitted.

Further, when the operation start date of the speed reducer 4 is not known, the date of the first grease replacement is assumed as follows. As shown in FIG. 10, the day when the additive consumption rate is zero (indicated by the consumption rate P0 in FIG. 10) is based on the slope of the straight line passing through the additive consumption rates P01 and P02 for two arbitrary days. is regarded as the operation start date, and a prediction time t1 from the operation start date to the day when the additive consumption rate reaches the management reference value (indicated by consumption rate P1 in FIG. 10) is predicted. In this way, the first grease exchange date can be predicted.

Next, the operation of predicting the second and subsequent grease replacement times will be described. FIG. 11 is a graph for explaining an example of predicting the second and subsequent grease replacement dates. Also in this prediction method, when the consumption rate of the additive in the grease in the casing 41 reaches a predetermined control reference value, it is time to replace the grease.

In the operation for predicting the second and subsequent grease replacement timings, the elapsed time from the start date of operation of the reduction gear 4 to the first grease replacement timing when the extent of the first grease replacement was confirmed, and the Nth grease replacement timing from the start date of operation. Based on the grease replacement rate R obtained when checking the degree of grease replacement, the N+1th grease replacement timing for checking the N+1th grease replacement degree from the operation start date is predicted. Note that N is a natural number.

Specifically, as shown in FIG. 11, the second and subsequent grease replacement dates are the time from the Nth (ie, this time) grease replacement date to the N+1th (ie, next) grease replacement date (hereinafter referred to as predicted (referred to as time t). In FIG. 11, "first grease replacement date", "second grease replacement date", etc. are referred to as "first grease replacement date", "second grease replacement date", etc., respectively. The predicted time t is obtained by Equation 2 below.
Formula 2: Predicted time t = Elapsed time t1 x Grease replacement rate R/100
Here, the elapsed time t1 is the time from the operation start date to the first grease replacement date. The grease exchange rate R is the grease exchange rate obtained when checking the degree of grease exchange for the Nth time, that is, the grease exchange rate obtained when performing the Nth grease exchange.

For example, when predicting the second grease replacement date (i.e., when N=1), the predicted time t2, which is the time from the first grease replacement date to the second grease replacement date, is obtained by Equation 2 above. be done. In this case, as the grease exchange rate R, the grease exchange rate R1 obtained when performing the first grease exchange is used. That is, the grease exchange rate R1 is obtained from the additive consumption rate P1 before grease exchange and the additive consumption rate P2 after grease exchange. A value obtained by multiplying the grease replacement rate R1 by the elapsed time t1 is derived as the predicted time t2. Further, when predicting the third grease replacement date (that is, when N=2), the predicted time t3, which is the time from the second grease replacement date to the third grease replacement date, is similarly expressed by Equation 2 above. sought by In this case, as the grease exchange rate R, the grease exchange rate R2 obtained when performing the second grease exchange is used. That is, the grease exchange rate R2 is obtained from the additive consumption rate P1(1) before grease exchange and the additive consumption rate P2(1) after grease exchange. A value obtained by multiplying the grease replacement rate R2 and the elapsed time t1 is derived as the predicted time t3. The consumption rate P1(1) and the consumption rate P2(1) are synonymous with the consumption rate P1 and the consumption rate P2, respectively, and the grease replacement rates R1 and R2 are synonymous with the grease replacement rate R. In this way, the second and subsequent grease replacement dates are predicted.

Further, when predicting the third and subsequent grease replacement dates (that is, when N≧2), the aforementioned predicted time t can also be obtained by Equation 3 below.
Formula 3: Predicted time t = elapsed time t/(first grease replacement rate R/100) x (second grease replacement rate R/100)
Here, the elapsed time t is the time from the (N-1)th grease replacement date to the Nth grease replacement date. The first grease exchange rate R is the grease exchange rate obtained when the grease is exchanged for the (N−1)th time. The second grease exchange rate R is the grease exchange rate obtained when the grease is exchanged for the Nth time. For example, when predicting the third grease replacement date (that is, when N=2), the elapsed time t is the elapsed time t2 from the first grease replacement date to the second grease replacement date. The first grease exchange rate R is the grease exchange rate R1 obtained when the first grease exchange is performed, and the second grease exchange rate R is the grease exchange rate obtained when the second grease exchange is performed. A rate R2 is used. When predicting the fourth grease replacement date (that is, when N=3), the elapsed time t is the elapsed time t3 from the second grease replacement date to the third grease replacement date. As the first grease exchange rate R, the grease exchange rate R2 obtained when the grease was exchanged for the second time is used. The determined grease exchange rate is used. This method can also predict the third and subsequent grease replacement dates.

As described above, the grease replacement method of the embodiment is a grease replacement method for the speed reducer 4 (gear device) having the casing 41 in which gears are accommodated and a specified amount of grease is enclosed. The grease replacement method consists of discharging the old grease Go from the casing 41 and injecting new grease Gn into the casing 41 until the amount of grease in the casing 41 exceeds a specified amount. After that, rotating the gear, and after rotating the gear, performing an amount adjusting operation for discharging the mixed grease Gm from the casing 41 until the amount of grease in the casing 41 reaches a specified amount.

According to this configuration, the new grease Gn is injected into the casing 41 until the amount of grease in the casing 41 exceeds the specified amount in the replacement operation. The amount of new grease Gn to be injected into the casing 41 can be increased compared to the case of injecting Gn. Further, by rotating the gear, it is possible to mix the old grease Go remaining in the casing 41, which is difficult to discharge, with the injected new grease Gn. Since the mixed grease Gm mixed in this way is discharged until it reaches the specified amount, the ratio of the new grease Gn contained in the specified amount of grease in the casing 41 increases. That is, by discharging the mixed grease Gm, a part of the old grease Go that is difficult to discharge from within the casing 41 is discharged. The proportion of grease Gn increases. Therefore, according to this grease exchange method, the grease exchange rate R can be improved.

Further, in the grease replacement method of the above embodiment, the casing 41 is opened to the outside air when the gear rotates.

According to this configuration, since the inside of the casing 41 is open to the outside air, it is possible to prevent an abnormal increase in pressure due to the rotation of the gear inside the casing 41 . Therefore, it is possible to prevent the seal member from being damaged due to an abnormal increase in the pressure inside the casing 41 .

Further, in the grease replacement method of the above embodiment, in the replacement operation, after the old grease Go is discharged from the casing 41, new grease Gn is injected into the casing 41 from the first through hole 42 formed in the lower portion of the casing 41. , when injecting new grease Gn into the casing 41 from the first through-hole 42, the second through-hole 43 formed in the upper part of the casing 41 is connected to an auxiliary container 47 that can be opened to the outside air.

According to this configuration, the new grease Gn can be injected until the new grease Gn in the casing 41 enters the auxiliary container 47 through the second through-hole 43 . Therefore, the casing 41 can be easily filled with grease without spilling the new grease Gn from the casing 41 onto the floor or the like. By injecting the new grease Gn until the grease in the casing 41 is filled up in this way, the maximum amount of the new grease Gn to be injected into the casing 41 can be obtained. Therefore, the grease exchange rate R can be further improved.

Further, in the grease replacement method of the above embodiment, the consumption rate P1 of the additive of the old grease Go in the casing 41 before performing the replacement operation and the additive of the mixed grease Gm in the casing 41 after the amount adjustment operation It further includes obtaining a grease replacement rate R based on the consumption rate P2 and confirming the degree of grease replacement.

According to this configuration, the grease exchange rate R is obtained based on the consumption rate of the additive, which is a parameter that appropriately reflects the difference between the old grease Go and the new grease Gn. It can be said that it is an index. Therefore, by obtaining such a grease replacement rate R, the degree of grease replacement can be reliably confirmed. By confirming the degree of grease exchange, the effectiveness of grease exchange can be confirmed and evaluated.

Further, in the grease replacement method of the above embodiment, the grease replacement rate R is obtained by Equation 1 above.

With this configuration, the grease replacement rate R can be realized.

Further, in the grease exchange method of the above embodiment, the additive is a phosphorus compound or a compound containing a phosphorus-sulfur double bond group.

According to this configuration, a phosphorus compound or a compound containing a phosphorus-sulfur double bond group is a main component as an additive for grease, so the grease exchange rate R can be obtained based on the consumption rate of such an additive. A more appropriate grease exchange rate R can be calculated by

Further, in the grease replacement method of the above embodiment, the elapsed time t1 from the operation start date of the speed reducer 4 (gear device) to the first grease replacement timing when the degree of the first grease replacement is confirmed, and from the operation start date Predicting the timing of the N+1th grease replacement for checking the N+1th grease replacement degree from the operation start date based on the grease replacement rate R obtained when checking the Nth (N is a natural number) grease replacement degree. further includes

According to this configuration, it is possible to predict the timing of the N+1-th (that is, next) grease replacement with high accuracy. The timing of the N+1th grease replacement depends on the grease replacement rate R of the Nth (that is, this time). That is, the higher the current grease replacement rate R, the longer the time until the next grease replacement time. The next grease replacement timing predicted based on the grease replacement rate R and the elapsed time t1 from the operation start date to the first grease replacement timing has high prediction accuracy.

Further, the grease replacement method of the embodiment includes a method for confirming the degree of grease replacement. This method of confirming the degree of grease replacement solves the problem of grasping the degree of grease replacement, which is different from the problem of improving the grease replacement rate R.

Specifically, the method for confirming the degree of grease replacement is as follows: in a speed reducer 4 (gear device) having a casing 41 in which gears are housed and grease is sealed, old grease Go is discharged from the casing 41 and new grease Gn is introduced into the casing 41. This is a method for confirming the degree of grease exchange when the grease to be injected into the is exchanged. The method for confirming the degree of grease replacement is the consumption rate P1 of the additive of the old grease Go in the casing 41 before the grease replacement is performed (that is, before the old grease Go is discharged), and This includes determining the grease replacement rate R based on the additive consumption rate P2 of the grease in the casing 41 (that is, after the new grease Gn is injected) and confirming the degree of grease replacement.

According to this configuration, the grease exchange rate R is obtained based on the consumption rate of the additive, which is a parameter that appropriately reflects the difference between the old grease Go and the new grease Gn. It can be said that it is an index. Therefore, by confirming the degree of grease replacement for which the grease replacement rate R is obtained, the degree of grease replacement can be reliably grasped. By grasping the degree of grease replacement, for example, it is possible to appropriately predict the timing of the next grease replacement.

In addition, in the method for confirming the degree of grease replacement, the grease replacement rate R is obtained by Equation 1 above.

With this configuration, the grease replacement rate R can be realized.

In the method for checking the degree of grease exchange, the additive is a phosphorus compound or a compound containing a phosphorus-sulfur double bond group.

According to this configuration, a phosphorus compound or a compound containing a phosphorus-sulfur double bond group is a main component as an additive for grease, so the grease exchange rate R can be obtained based on the consumption rate of such an additive. A more appropriate grease exchange rate R can be calculated by Therefore, it is possible to more accurately grasp the degree of grease replacement.

In addition, the method for confirming the degree of grease replacement includes the elapsed time t1 from the start date of operation of the speed reducer 4 (gear device) to the timing of the first grease replacement when the degree of grease replacement was confirmed for the first time, and N from the start date of operation. Predicting the timing of the N+1th grease replacement for checking the N+1th grease replacement degree from the operation start date based on the grease replacement rate R obtained when checking the grease replacement degree for the (N is a natural number) time. Including further.

According to this configuration, it is possible to predict the timing of the N+1-th (that is, next) grease replacement with high accuracy. The timing of the N+1th grease replacement depends on the grease replacement rate R of the Nth (that is, this time). That is, the higher the current grease replacement rate R, the longer the time until the next grease replacement time. The next grease replacement timing predicted based on the grease replacement rate R and the elapsed time t1 from the operation start date to the first grease replacement timing has high prediction accuracy.

<<Other embodiments>>
As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, replacements, additions, omissions, etc. are made as appropriate. Moreover, it is also possible to combine the constituent elements described in the above embodiments to create new embodiments. In addition, among the components described in the attached drawings and detailed description, there are not only components essential for solving the problem, but also components not essential for solving the problem in order to exemplify the above technology. can also be included. Therefore, it should not be immediately recognized that those non-essential components are essential just because they are described in the attached drawings and detailed description.

For example, in the replacement operation of steps S1 to S3 of the above embodiment, the old grease Go is discharged from the casing 41 and then the new grease Gn is injected into the casing 41. However, the new grease Gn is injected into the casing 41. However, the old grease Go may be discharged from the casing 41 . In that case, the connecting operation of the auxiliary container 47 (step S2) is omitted.

12 to 14 are schematic diagrams showing one state when the grease of the speed reducer 4 is replaced. Specifically, in the replacement operation according to this modification, new grease Gn is injected from the first through-hole 42 into the casing 41 in the speed reducer 4 in which the specified amount of the old grease Go is enclosed (see FIG. 12). . At this time, the second through hole 43 is open. In this replacement operation, as shown in FIG. 13, old grease Go inside the casing 41 is discharged from the second through hole 43 as the new grease Gn is injected into the casing 41 .

Then, as shown in FIG. 14, when the new grease Gn reaches the second through hole 43, the injection operation of the new grease Gn is completed. Since the old grease Go and the new grease Gn are different in color, when the color of the grease discharged from the second through hole 43 changes to the color of the new grease Gn, the old grease Go is discharged from the casing 41 and the new grease is discharged. It is understood that Gn has reached the second through hole 43 . Thus, when the injection operation of the new grease Gn is completed, the replacement operation is completed. After the replacement operation is completed, the operations after step S4 shown in FIG. 2 are sequentially performed as in the above-described embodiment. That is, the old grease Go and the new grease Gn of the difficult-to-discharge portion 44 are mixed by the rotation operation of the gear (step S4), and the mixed grease is kept in the casing 41 until it reaches the specified amount by the amount adjustment operation (step S5). discharged from

Thus, in the replacement operation of this modified example as well, new grease Gn is supplied to the casing 41 until the amount of grease in the casing 41 exceeds the specified amount, more specifically, until the grease in the casing 41 becomes full. injection operation is performed. By injecting the new grease Gn until the grease in the casing 41 is filled up in this manner, the amount of the new grease Gn to be injected into the casing 41 can be increased as in the above-described embodiment. Therefore, the grease exchange rate R is improved.

Further, in the above embodiment, the reduction gear 4 provided in the robot 100 is targeted as a gear device, but the technology disclosed herein is not limited to this, and may be applied to a reduction gear provided in a machine tool, for example.

Further, the gear device is not limited to the speed reducer 4, and may be, for example, a gear train that transmits power without speed reduction.

Further, the additive related to the additive consumption rates P1 and P2 may be a component other than a phosphorus compound or a compound containing a phosphorus-sulfur double bond group.

Also, the auxiliary container 47 may be connected to the second through hole 43 not directly but via a tube or the like.

Alternatively, the auxiliary container 47 may be omitted, and the grease from the second through-hole 43 may be guided by a tube or the like to a container (for example, a bucket) placed at a position lower than the casing 41 such as the floor. In this case, by opening one end of the tube on the container side directly to the outside air, or by opening one end of the tube on the container side to the outside air through the grease in the container, the inside of the casing 41 is exposed to the outside air. open to This container and tube are installed even when the gear rotates (step S4), like the auxiliary container 47 in the above-described embodiment. Also, this container and tube can be applied to the modifications described with reference to FIGS. 12-14.

Further, in the grease replacement method of the above embodiment, the operation of connecting the auxiliary container 47 (step S2) may be omitted. In this case, in the grease injection operation (step S3), for example, as shown in FIG. 15, new grease Gn is injected into the casing 41 from the first through hole 42 while the second through hole 43 is open. . New grease Gn is injected into the casing 41 until the grease in the casing 41 exceeds the prescribed height H, more specifically, until the grease in the casing 41 is filled. Further, the gear rotating operation (step S4) and the grease amount adjusting operation (step S5) are performed, for example, while the second through hole 43 is open.

When the auxiliary container 47 is omitted, for example, when the gear rotates (step S4), the second through hole 43 is closed while the gear is rotated slowly so that the pressure does not rise above a certain level. good too.

When the auxiliary container 47 is omitted, for example, when rotating the gear (step S4) with the second through hole 43 open, the amount of grease spilled from the second through hole 43 is within the allowable range. For example, the gear may be rotated knowing that the grease will spill out. In order to prevent the grease from spilling out of the second through-hole 43, the rotation speed of the gear is suppressed, or the gear is rotated in a state where the amount of grease in the casing 41 is increased to a specified amount or more but not filled. can be

Also, the grease injection operation (step S3) and the gear rotation operation (step S4) are performed independently, but they may be performed in parallel. In other words, the gear may be rotated while the new grease Gn is being injected into the casing 41 .

In addition, in the grease discharge operation (step S1), instead of using a suction cylinder to suck the old grease Go from the first through hole 42, for example, pressurized air may be supplied into the casing 41 from the second through hole 43. Therefore, a configuration in which the old grease Go is discharged from the first through hole 42 may be adopted. When the auxiliary container 47 is connected to the second through-hole 43, a lid having an opening may be appropriately attached to the auxiliary container 47, and pressurized air may be supplied into the casing 41 from the opening of the lid. good. In those cases, in order to prevent the grease from scattering from the first through hole 42, a tube or the like is connected to the first through hole 42, and the old grease Go is discharged into a grease disposal bucket or the like through the tube. You may do so. This configuration can also be employed in the above-described modified example in which the auxiliary container 47 is omitted.

Further, in the above-described embodiment, the operation of predicting the replacement time in step S7 may be omitted, and the operation of confirming the degree of grease replacement in step S6 may be omitted in addition to step S7.

4 reducer (gear device)
41 Casing 42 First through hole 43 Second through hole 47 Auxiliary container Go Old grease (grease)
Gn new grease (new grease)
Gm mixed grease (grease)
P1 Consumption rate of additive P2 Consumption rate of additive R Grease exchange rate t1 Elapsed time

Claims (11)

A grease replacement method in a gear device having a casing in which a gear is housed and a specified amount of grease is enclosed,
performing a replacement operation of discharging grease from the casing and injecting new grease into the casing until the amount of grease in the casing exceeds the specified amount;
Rotating the gear after the switching operation;
and performing an amount adjusting operation for discharging grease from the casing until the amount of grease in the casing reaches the specified amount after the gear rotating operation. In the grease replacement method according to claim 1,
A grease replacement method for exposing the casing to the outside air when the gear rotates. In the grease replacement method according to claim 1 or 2,
In the replacement operation, after the grease is discharged from the casing, new grease is injected into the casing from a first through hole formed in the lower part of the casing,
A method of exchanging grease, wherein when new grease is injected into the casing from the first through hole, an auxiliary container that can be opened to the outside air is connected to a second through hole formed in an upper part of the casing. In the grease replacement method according to any one of claims 1 to 3,
A grease replacement rate R is calculated based on the additive consumption rate P1 of the grease in the casing before the replacement operation and the additive consumption rate P2 of the grease in the casing after the amount adjustment operation. A grease replacement method further comprising obtaining and confirming the degree of grease replacement. In the grease replacement method according to claim 4,
The grease exchange rate R is a grease exchange method obtained by the following formula 1.
Formula 1: R = ((P1-P2)/P1) x 100 In the grease replacement method according to claim 4 or 5,
The grease exchange method, wherein the additive is a phosphorus compound or a compound containing a phosphorus-sulfur double bond group. In the grease replacement method according to any one of claims 4 to 6,
Elapsed time from the operation start date of the gear device to the first grease replacement timing when the first grease replacement degree is confirmed, and the grease obtained when checking the N-th grease replacement degree from the operation start date a grease replacement method further comprising predicting the N+1th grease replacement timing for confirming the degree of N+1th grease replacement from the operation start date based on the replacement rate R. A method for checking the degree of grease replacement when grease is replaced by discharging grease from the casing and injecting new grease into the casing in a gear device having a casing in which a gear is housed and grease is sealed, comprising:
A grease replacement rate based on an additive consumption rate P1 of grease in the casing before the grease replacement is performed and an additive consumption rate P2 of grease in the casing after the grease replacement is performed A method for confirming the degree of grease replacement, including obtaining R to confirm the degree of grease replacement. In the method for checking the degree of grease replacement according to claim 8,
The grease exchange rate R is a method for confirming the degree of grease exchange, which is obtained by the following formula 1.
Formula 1: R = ((P1-P2)/P1) x 100 In the method for checking the degree of grease replacement according to claim 8 or 9,
The method for confirming the degree of grease exchange, wherein the additive is a phosphorus compound or a compound containing a phosphorus-sulfur double bond group. In the method for checking the degree of grease replacement according to any one of claims 8 to 10,
Elapsed time from the operation start date of the gear device to the first grease replacement timing when the first grease replacement degree is confirmed, and the grease obtained when checking the N-th grease replacement degree from the operation start date A method for confirming the degree of grease replacement, further comprising predicting the timing of the N+1th grease replacement for confirming the degree of grease replacement for the N+1th time from the operation start date based on the replacement rate R.

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