JP2016173110A - Lubricating oil supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that, while an operator can only confirm resupply of a required amount of lubricating oil during resupplying the lubricating oil into an internal space of a housing, a conventional turning device cannot keep the amount of the lubricating oil as required without operator's work for resupplying the lubricating oil.SOLUTION: When average driving torque Nav is not lower than a threshold value Nx during the turning operation of a second arm and an internal temperature T of a speed reduction mechanism is not lower than a high temperature side reference temperature TH, a main control part of a robot control device controls the supply amount of the lubricating oil to the internal space of the speed reduction mechanism to be increased. Besides, when the average driving torque Nav is not lower than the threshold value Nx during the turning operation of the second arm and the internal temperature T of the speed reduction mechanism is not lower than a low temperature side reference temperature TL but lower than the high temperature side reference temperature TH, the main control part of the robot control device controls the discharge amount of the lubricating oil from the internal space of the speed reduction mechanism to be increased.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a lubricating oil supply apparatus.

  Conventionally, a technique for maintaining lubricity by supplying lubricating oil to a mechanism having gears, bearings, and the like is known. For example, in the swivel device of Patent Document 1, an output shaft that outputs the driving force of the swivel motor is inserted in the center of a substantially cylindrical housing, and a bearing is interposed between the inner surface of the housing and the outer surface of the output shaft. ing. In addition, the housing of the swivel device of Patent Document 1 is provided with a supply pipe portion for supplying lubricating oil from the outside to the internal space of the housing, and discharges the lubricating oil from the internal space of the housing to the outside. A discharge pipe portion is formed.

  When lubricating oil is replenished to the internal space of the housing in the swivel device of Patent Document 1, the operator of the swivel device supplies the lubricating oil to the internal space of the housing via the supply pipe portion. When the oil level of the lubricating oil reaches the discharge pipe in the internal space of the housing, the lubricating oil is discharged to the outside through the discharge pipe of the housing as the lubricating oil is supplied. Therefore, by discharging the lubricating oil from the discharge pipe portion of the housing, the operator can confirm that the required amount of lubricating oil has been replenished in the internal space of the housing.

JP 2013-231465 A

  In the swivel device of Patent Document 1, the amount of lubricating oil supplied to the internal space of the housing decreases as the lubricating oil evaporates or leaks as it is driven. However, in the swivel device disclosed in Patent Document 1, the operator can only confirm that the required amount of lubricating oil has been replenished when the lubricating oil is replenished to the internal space of the housing. On the other hand, the swivel device disclosed in Patent Document 1 cannot maintain the amount of lubricating oil present in the internal space of the housing at a necessary amount without replenishment of lubricating oil by an operator. Therefore, there is a possibility that the lubrication state of the turning device of Patent Document 1 deteriorates as it is driven.

  The present invention has been made in view of such circumstances of the prior art, and an object thereof is to maintain a lubrication state of a lubrication target mechanism in a more appropriate state.

  In order to achieve the above object, a lubricating oil supply apparatus according to the present invention includes a supply unit that supplies lubricating oil to a lubrication target mechanism, a discharge unit that discharges lubricating oil from the lubrication target mechanism, and the lubrication target. A temperature detection unit that detects an internal temperature of the mechanism; and a control unit that receives a drive torque signal indicating a drive torque when driving the mechanism to be lubricated, and the control unit receives the input drive torque signal. When the drive torque shown is equal to or greater than a threshold value, the at least one of the supply unit and the discharge unit is controlled in accordance with the internal temperature detected by the temperature detection unit, so It is characterized by adjusting the amount of lubricating oil.

  According to the present invention, the lubrication state of the lubrication target mechanism can be maintained in an appropriate state.

The side view of an articulated robot and the block diagram of a robot control apparatus. Sectional drawing of the joint structure in an articulated robot. Explanatory drawing which shows the hydraulic circuit in a lubricating oil supply apparatus. The flowchart explaining supply control of lubricating oil.

(Robot control system configuration)
An embodiment in which the lubricating oil supply apparatus 50 of the present invention is applied to a robot control system that performs arc welding will be described. First, a schematic configuration of an articulated robot R (hereinafter abbreviated as robot R) will be described.

  As shown in FIG. 1, a swivel base C2 is provided on an upper part of a base C1 of the robot R so as to be turnable about a first rotation axis J1. A first arm C3 is provided above the swivel base C2 so as to be pivotable about the second rotation axis J2. A second arm C4 is provided at the distal end of the first arm C3 so as to be rotatable about a third rotation axis J3 orthogonal to the second rotation axis J2. A third arm C5 is provided at the tip of the second arm C4 so as to be pivotable about a fourth rotation axis J4 orthogonal to the third rotation axis J3.

  As shown in FIG. 1, a fourth arm C6 is provided at the distal end of the third arm C5 so as to be rotatable about the fifth rotation axis J5. A fifth arm C7 is provided at the tip of the fourth arm C6 so as to be rotatable about a sixth rotation axis J6 orthogonal to the fifth rotation axis J5. A tool fixing member C8 is provided at the tip of the fifth arm C7 so as to be pivotable about a seventh rotation axis J7 orthogonal to the sixth rotation axis J6. A welding torch C9 is fixed to the tool fixing member C8 as a work tool, and the welding torch C9 rotates integrally with the tool fixing member C8. The fourth arm C6, the fifth arm C7, and the tool fixing member C8 may be collectively referred to as a wrist assembly. The swivel base C2, the first arm C3 to the fifth arm C7, and the tool fixing member C8 each turn using a servo motor controlled by the robot controller RC as a drive source.

  Next, a connection structure between the first arm C3 and the second arm C4 in the robot R will be described. In addition, since the 1st arm C3 is a fixed side (base C1) side rather than the 2nd arm C4, it is equivalent to a fixed side member in the relationship with the 2nd arm C4. Further, since the second arm C4 can turn (turn) with respect to the first arm C3, it corresponds to a movable member in relation to the first arm C3.

  As shown in FIG. 2, the first housing 11 of the first arm C <b> 3 is formed to have a hollow portion 11 a to which a power cable PC or the like can be wired on the distal end side (upper side in FIG. 2). A circular through hole 12 is formed in the wall portion on the distal end side of the first housing 11. The center of the through hole 12 is located on the third rotation axis J3. An opening 13 is formed in the wall of the first housing 11, and a first cover 14 is detachably attached to the opening 13.

  As shown in FIG. 2, a main body portion 41 of the speed reduction mechanism 40 is fixed to the upper surface of the wall portion on the distal end side of the first housing 11 in the first arm C3 with screws or the like. The main body 41 has a substantially cylindrical shape as a whole, and its central axis coincides with the third rotation axis J3. The inner diameter of the main body 41 is formed to be the same as the inner diameter of the through hole 12 of the first housing 11 in the first arm C3. An annular convex portion 42 projects from the front end surface of the main body 41 (the upper surface in FIG. 2) so as to surround the opening. A substantially disc-shaped first gear 43 having a plurality of teeth on the outer periphery is fixed to the front end surface of the convex portion 42 with a screw or the like. The first gear 43 is fixed to the convex portion 42 so that the center of rotation coincides with the third rotation axis J3.

  As shown in FIG. 2, a substantially disc-shaped second gear 44 having a plurality of teeth on the outer periphery is disposed on the radially outer side of the first gear 43 (right side in the left-right direction in FIG. 2). The second gear 44 is disposed so that the center of rotation is parallel to the third rotation axis J3, and is disposed at the same position as the first gear 43 in the direction of the third rotation axis J3. The diameter of the second gear 44 is smaller than the diameter of the first gear 43. Then, the teeth on the outer periphery of the second gear 44 mesh with the teeth on the outer periphery of the first gear 43. In the present embodiment, the first gear 43 and the second gear 44 constitute a reduction gear unit.

  As shown in FIG. 2, a gear housing 45 that covers the first gear 43 and the second gear 44 from the radially outer side is attached to the distal end surface of the main body 41. The gear housing 45 is attached to the main body 41 via a bearing member, a seal member, and the like (not shown), and is rotatable about the third rotation axis J3.

  As shown in FIG. 2, the second housing 21 of the second arm C <b> 4 is fixed to the distal end side (the upper side in FIG. 2) of the gear housing 45 in the speed reduction mechanism 40 with a screw or the like. The second housing 21 of the second arm C4 is formed to have a hollow portion 21a that can be wired with a power cable PC or the like on the base end side (lower side in FIG. 2). A circular through hole 22 is formed in the base end side wall portion of the second housing 21. The center of the through hole 22 is located on the third rotation axis J3. A cylindrical tubular body 25 is inserted into the through hole 22. The upper end portion of the cylindrical body 25 is fixed to the surface on the hollow portion 21 a side in the wall portion on the proximal end side of the second housing 21 with a screw or the like. The cylindrical body 25 is inserted through the through hole 12 in the first housing 11 of the main body 41 of the speed reduction mechanism 40 and the first arm C3. Therefore, the hollow portion 11a of the first arm C3 communicates with the hollow portion 21a of the second arm C4 via the inside of the cylindrical body 25. An opening 23 is formed in the wall portion of the second housing 21, and a second cover 24 is detachably attached to the opening 23.

  As shown in FIG. 2, a plate-like motor mounting portion 31 is fixed to the surface opposite to the hollow portion 21a of the second housing 21 so as to extend along a direction orthogonal to the third rotation axis J3. Has been. The motor mounting portion 31 extends so as to reach the front end side surface of the gear housing 45 in the speed reduction mechanism 40, and is also fixed to the front end side surface of the gear housing 45 with a screw or the like. A circular through hole 32 is formed in the motor placement portion 31. A servo motor 33 is mounted on the motor mounting portion 31. The output shaft 34 of the servo motor 33 is inserted through the through hole 32 of the motor mounting portion 31. And the front-end | tip part of the output shaft 34 of the servomotor 33 protrudes from the side in which the servomotor 33 is mounted to the 1st arm C3 side. The tip of the output shaft 34 is fixed to the second gear 44 in the gear housing 45 of the speed reduction mechanism 40. A motor cover 35 for covering the servo motor 33 is detachably attached to the side of the motor placement portion 31 where the servo motor 33 is placed.

  In the present embodiment, when the servo motor 33 is driven and the output shaft 34 rotates, the second gear 44 rotates around the first gear 43 while rotating. At this time, the gear housing 45 of the speed reduction mechanism 40 also rotates about the third rotation axis J3. Accordingly, the second arm C4 fixed to the gear housing 45 also rotates about the third rotation axis J3. Further, since the diameter of the first gear 43 is larger than the diameter of the second gear 44, the second gear 44 rolls around the first gear 43 rather than the rotational speed of the second gear 44. Accordingly, the second arm C4 turns at a predetermined rotational speed obtained by reducing the rotational speed of the output shaft 34 of the servo motor 33 by the ratio of the diameters of the first gear 43 and the second gear 44. To do.

  As shown in FIG. 2, the speed reduction mechanism 40 has an internal space 40 a that is partitioned by a main body 41, a gear housing 45, the second housing 21 of the second arm C <b> 4, and the motor placement portion 31. The internal space 40a is preferably a sealed space, but is not necessarily a sealed space as long as excessive leakage of lubricating oil does not occur. The gear housing 45 is provided with a supply port (not shown) for supplying the lubricating oil to the internal space 40a and a discharge port (not shown) for discharging the lubricating oil to the outside. The internal space 40a of the speed reduction mechanism 40 is provided with a temperature sensor 46 as a temperature detection unit that measures the internal temperature T of the internal space 40a. In the present embodiment, the temperature sensor 46 is fixed to the surface of the motor placement unit 31 on the first arm C3 side. A signal line of the temperature sensor 46 is drawn out to a side of the motor mounting portion 31 on which the servo motor 33 is mounted through a hole (not shown) formed in the motor mounting portion 31. The temperature sensor 46 outputs a temperature detection signal S4 indicating the measured internal temperature T via the signal line. In addition, as the temperature sensor 46, a thermocouple sensor etc. are employable, for example.

Next, a hydraulic circuit in the lubricating oil supply device 50 will be described.
As shown in FIG. 3, the upstream end of the discharge oil passage 51 is connected to the speed reduction mechanism 40 (gear housing 45), and the lubricating oil tank 54 is connected to the downstream end of the discharge oil passage 51. The discharge oil passage 51 is provided with a discharge valve 52 that adjusts the amount of lubricating oil discharged from the internal space 40 a of the speed reduction mechanism 40. The discharge valve 52 is a flow rate control valve whose opening degree can be adjusted. A filter 53 for removing foreign matter / impurities in the lubricating oil is provided downstream of the discharge valve 52 in the discharge oil passage 51.

  As shown in FIG. 3, the upstream end of the supply oil passage 55 is connected to the lubricating oil tank 54, and the speed reduction mechanism 40 is connected to the downstream end of the supply oil passage 55. The supply oil passage 55 is provided with a pump 56 that pumps the lubricating oil stored in the lubricating oil tank 54. The pump 56 is drivingly connected to the electric motor 57 and generates a predetermined hydraulic pressure as the electric motor 57 is driven. In the present embodiment, the electric motor 57 is controlled so that the pump 56 generates a constant hydraulic pressure. A supply valve 59 for adjusting the amount of lubricating oil supplied to the internal space 40 a of the speed reduction mechanism 40 is provided downstream of the pump 56 in the supply oil passage 55. The supply valve 59 is a flow rate control valve whose opening degree can be adjusted. In the supply oil passage 55, an electric heater 60 is disposed adjacent to the downstream side of the pump 56 and the upstream side of the supply valve 59. When the electric heater 60 is turned on, the temperature of the lubricating oil in the supply oil passage 55 increases. And the temperature of the lubricating oil which exists in the said internal space 40a rises because the lubricated oil heated up is supplied to the internal space 40a of the deceleration mechanism 40. Therefore, the electric heater 60 functions as a temperature adjustment unit that adjusts the temperature of the lubricating oil in the internal space 40 a of the speed reduction mechanism 40.

  As shown in FIG. 3, the lubricating oil discharged from the speed reduction mechanism 40 is supplied again to the speed reduction mechanism 40 through the discharged oil path 51, the lubricating oil tank 54, and the supply oil path 55. A series of circulating oil passages extending from the discharge oil passage 51 to the supply oil passage 55, the electric heater 60, and the temperature sensor 46 disposed in the internal space 40 a of the speed reduction mechanism 40 constitute a lubricating oil supply device 50. is there. The discharge oil passage 51 and the discharge valve 52 correspond to a discharge portion that discharges the lubricating oil from the internal space 40 a of the speed reduction mechanism 40, and the supply oil passage 55, the pump 56, and the supply valve 59 are in the internal space 40 a of the speed reduction mechanism 40. It corresponds to a supply unit that supplies lubricating oil. The speed reduction mechanism 40 corresponds to a lubrication target mechanism that is lubricated by the lubricating oil supply device 50.

  Next, the robot controller RC that controls the robot R will be described. In the following description, the control of the turning motion of the second arm C4 will be described. The control of the turning operation of the turntable C2, other arms, and the tool fixing member C8 is the same as the control of the turning operation of the second arm C4, and thus the description thereof is omitted.

  As shown in FIG. 1, a robot controller RC is connected to a base C1 of the robot R via a communication cable (shown by a broken line in FIG. 1). The main control unit 71 of the robot controller RC includes a central processing unit 72 (CPU) that executes various programs, a volatile memory 73 in which data is temporarily stored when each program is executed, a program required for processing, The computer includes a nonvolatile storage unit 74 and the like in which various data are stored.

  As shown in FIG. 1, the robot controller RC has a built-in servo amplifier 75 that supplies power to the servomotor 33 of the second arm C4 of the robot R. The servo amplifier 75 supplies power corresponding to the attitude control signal S1 output from the main control unit 71 to the servo motor 33 of the second arm C4. In addition, the servo amplifier 75 detects the amount of power required to rotate the second arm C4 by a unit angle as needed. Each time the servo amplifier 75 detects the power amount, the servo amplifier 75 calculates an average value of the power amount for the past predetermined number of times including the latest power amount. The average value of the electric energy represents an average of driving torque required per unit angle when the second arm C4 is turned at a constant angle. The servo amplifier 75 outputs an average value of the calculated electric energy as needed as a drive torque signal S2 indicating a drive torque when driving the second arm C4.

  As shown in FIG. 1, the robot controller RC is equipped with a warning light 76 and a buzzer 77 for calling attention to the operator of the robot R. The warning lamp 76 is lit for a predetermined time according to the error signal S3 output from the main control unit 71. The buzzer 77 emits a warning sound for a predetermined time according to the error signal S3 output from the main control unit 71.

  As shown in FIG. 1, the drive torque signal S <b> 2 output from the servo amplifier 75 is input to the main control unit 71. The main control unit 71 stores the average value of the electric energy indicated by the drive torque signal S2 in the memory 73 as the average drive torque Nav. The average driving torque Nav is updated to a new value every time the driving torque signal S2 is input to the main control unit 71. As shown in FIG. 3, the temperature detection signal S <b> 4 is input to the main controller 71 from the temperature sensor 46 disposed in the internal space 40 a of the speed reduction mechanism 40. As shown in FIG. 1, the main control unit 71 stores the internal temperature T indicated by the temperature detection signal S <b> 4 in the memory 73. The internal temperature T is updated to a new value every time the temperature detection signal S4 is input to the main control unit 71.

  As shown in FIG. 1, the storage unit 74 of the main control unit 71 stores a threshold value Nx related to the average driving torque Nav. As the threshold value Nx, an upper limit value that can be taken as a drive torque when the second arm C4 is turned by a unit angle under the normal operation of the robot R is set. The normal operation of the robot R is, for example, an allowable temperature range in which a necessary and sufficient amount of lubricating oil is supplied to the internal space 40a of the speed reduction mechanism 40, and the temperature of the lubricating oil can appropriately exhibit lubricity. This is the state. The storage unit 74 stores a low-temperature side reference temperature TL as a first reference temperature and a high-temperature side reference temperature TH as a second reference temperature. If the low temperature side reference temperature TL is less than that temperature, the viscosity of the lubricating oil supplied to the internal space 40a of the speed reduction mechanism 40 is equal to or higher than a certain value, so that the temperature of the lubricating oil must be increased (for example, 0 to 10 ° C.). It is defined as. The high temperature side reference temperature TH is determined as a temperature (for example, 60 to 80 ° C.) at which seizure is occurring due to insufficient supply of lubricating oil to the first gear 43 and the second gear 44 of the speed reduction mechanism 40. Yes.

  As shown in FIG. 3, the main control unit 71 of the robot control device RC generates a supply control signal S <b> 5 for controlling the opening degree of the supply valve 59 in the lubricating oil supply device 50 and outputs it to the supply valve 59. Further, the main control unit 71 generates a discharge control signal S <b> 6 for controlling the opening degree of the discharge valve 52 in the lubricating oil supply device 50, and outputs it to the discharge valve 52. That is, in the present embodiment, the main control unit 71 of the robot control device RC also functions as a control unit of the lubricating oil supply device 50. The main control unit 71 also controls on / off switching of the electric heater 60.

(Lubrication oil supply control in the lubricating oil supply device 50)
A process for controlling the supply of lubricant in the lubricant supply apparatus 50 will be described.
When the robot controller RC, the robot R, and the like are activated, the main controller 71 of the robot controller RC sets the openings of the supply valve 59 and the discharge valve 52 in the lubricant supply apparatus 50 to the initial openings. Process. Specifically, the main control unit 71 sets the opening degree of the supply valve 59 to a small value that is not zero. Therefore, the lubricating oil is supplied to the internal space 40a of the speed reduction mechanism 40 by a certain amount. Further, the main control unit 71 sets the opening degree of the discharge valve 52 to an opening degree at which substantially the same amount of lubricating oil as the supplied lubricating oil is discharged. Therefore, a certain amount of lubricating oil exists in the internal space 40a of the speed reduction mechanism 40 if the leakage of the lubricating oil, volatile components, and the like are ignored. Thus, after setting the opening degree of the supply valve 59 and the discharge valve 52 to the opening degree of the initial state, the processing of the main control unit 71 proceeds to step ST10 shown in FIG.

  In step ST10, the main control unit 71 compares the average drive torque Nav and the threshold value Nx to determine whether or not the average drive torque Nav is equal to or greater than the threshold value Nx. When average drive torque Nav is less than threshold value Nx (NO in step ST10), the lubricant supply control process is temporarily terminated, and the process of step ST10 is executed again. Therefore, in this case, the opening degree of the supply valve 59 and the discharge valve 52 is maintained in the initial state. On the other hand, when average drive torque Nav is equal to or greater than threshold value Nx (YES in step ST10), the process of main control unit 71 proceeds to step ST11.

  In step ST11, the main control unit 71 compares the internal temperature T of the speed reduction mechanism 40 with the high temperature side reference temperature TH, and determines whether or not the internal temperature T is equal to or higher than the high temperature side reference temperature TH. When internal temperature T is equal to or higher than high temperature side reference temperature TH (YES in step ST11), the process of main controller 71 proceeds to step ST12.

  In step ST12, the main control unit 71 performs control to increase the supply amount of the lubricating oil supplied to the internal space 40a of the speed reduction mechanism 40. Specifically, the main control unit 71 outputs a supply control signal S5 to the supply valve 59 in the lubricant supply device 50 for a certain period of time. The supply control signal S5 at this time is obtained by setting the opening degree of the supply valve 59 to be larger than the opening degree in the initial state. At this time, the opening of the discharge valve 52 remains the initial opening. Therefore, when the process of step ST12 is executed, the amount of lubricating oil present in the internal space 40a of the speed reduction mechanism 40 increases. When the predetermined time has elapsed and the opening of the supply valve 59 is returned to the initial opening, the processing of the main control unit 71 proceeds to step ST13.

  In step ST13, the main controller 71 compares the internal temperature T of the speed reduction mechanism 40 with the high temperature side reference temperature TH, and determines whether or not the internal temperature T is lower than the high temperature side reference temperature TH. When internal temperature T is lower than high-temperature side reference temperature TH (YES in step ST13), the lubricating oil supply control process is temporarily terminated, and the process of step ST10 is executed again. On the other hand, when internal temperature T is still higher than high temperature side reference temperature TH (NO in step ST13), the process of main control unit 71 proceeds to step ST14.

  In step ST14, the main control unit 71 determines that the internal temperature T of the speed reduction mechanism 40 cannot be lowered appropriately only by controlling the supply and discharge of the lubricating oil, and gives an error signal to the warning lamp 76 and the buzzer 77. S3 is output. The warning lamp 76 that has received the error signal S3 lights up for a predetermined period, and the buzzer 77 that has received the error signal S3 emits a warning sound for a predetermined period. After a predetermined period of time has elapsed, the lubricant supply control process is temporarily terminated, and the process of step ST10 is executed again.

  On the other hand, when it is determined in step ST11 that the internal temperature T is lower than the high temperature side reference temperature TH (NO in step ST11), the process of the main control unit 71 proceeds to step ST21. In step ST21, the internal temperature T of the speed reduction mechanism 40 is compared with the low temperature side reference temperature TL to determine whether the internal temperature T is lower than the low temperature side reference temperature TL. When internal temperature T is lower than low temperature side reference temperature TL (YES in step ST21), the process of main controller 71 proceeds to step ST22.

  In step ST22, the main control unit 71 switches on the electric heater 60. At this time, the opening degree of the supply valve 59 of the lubricating oil supply device 50 remains in the initial state, and a certain amount of lubricating oil is supplied to the internal space 40 a of the speed reduction mechanism 40. Therefore, the lubricating oil warmed by turning on the electric heater 60 is supplied to the internal space 40 a of the speed reduction mechanism 40. After this process, the process of the main control unit 71 proceeds to step ST23.

  In step ST23, the main control unit 71 determines whether or not the internal temperature T of the speed reduction mechanism 40 has become equal to or higher than the low temperature side reference temperature TL. When internal temperature T of deceleration mechanism 40 is still lower than low temperature side reference temperature TL (NO in step ST23), main controller 71 waits for internal temperature T to become equal to or higher than low temperature side reference temperature TL. When the internal temperature T is equal to or higher than the low temperature side reference temperature TL (YES in step ST23), the process of the main control unit 71 moves to step ST24, and the main control unit 71 switches off the electric heater 60. Thereafter, the supply control process of the lubricating oil is temporarily terminated, and the process of step ST10 is executed again.

  On the other hand, when it is determined in step ST21 that the internal temperature T is equal to or higher than the low temperature side reference temperature TL (NO in step ST21), the process of the main control unit 71 proceeds to step ST31. In step ST31, the main control unit 71 performs control to increase the amount of lubricant discharged from the internal space 40a of the speed reduction mechanism 40. Specifically, the main control unit 71 outputs a discharge control signal S6 to the discharge valve 52 in the lubricating oil supply device 50 for a certain period of time. The discharge control signal S6 at this time is obtained by setting the opening degree of the discharge valve 52 to be larger than the opening degree in the initial state. At this time, the opening degree of the supply valve 59 remains the initial opening degree. Therefore, when the process of step ST31 is executed, the amount of lubricating oil present in the internal space 40a of the speed reduction mechanism 40 decreases. When the predetermined time has elapsed and the opening of the discharge valve 52 is returned to the initial opening, the process of the main control unit 71 proceeds to step ST32.

  In step ST32, the average drive torque Nav is compared with the threshold value Nx to determine whether or not the average drive torque Nav is less than the threshold value Nx. When average drive torque Nav is less than threshold value Nx (YES in step ST32), the lubricant supply control process is temporarily terminated, and the process of step ST10 is executed again. On the other hand, when average drive torque Nav is still greater than or equal to threshold value Nx (NO in step ST32), the process of main control unit 71 proceeds to step ST33.

  In step ST33, the main control unit 71 determines that the driving torque of the second arm C4 cannot be reduced only by controlling the supply / discharge of the lubricating oil and the temperature of the lubricating oil. The error signal S3 is output to 77. The warning lamp 76 that has received the error signal S3 lights up for a predetermined period, and the buzzer 77 that has received the error signal S3 emits a warning sound for a predetermined period. After a predetermined period of time has elapsed, the lubricant supply control process is temporarily terminated, and the process of step ST10 is executed again.

  As described above, a series of processing starting from step ST10 is repeatedly executed (looped) while the robot R is operating. Therefore, the lubricating state of the speed reduction mechanism 40 during operation of the robot R is constantly monitored by the lubricating oil supply device 50. When the operation of the robot R is stopped, the lubricating oil supply control process ends accordingly.

(Features of the embodiment)
Hereinafter, the characteristics of the above embodiment will be described together with the operation thereof.
(1) In the above embodiment, when the average driving torque Nav is equal to or greater than the threshold value Nx, according to the comparison result between the internal temperature T of the speed reduction mechanism 40 and the high temperature side reference temperature TH and the low temperature side reference temperature TL. The opening degree of the discharge valve 52 or the supply valve 59 in the lubricating oil supply device 50 is controlled. Therefore, appropriate supply and discharge of lubricating oil according to the internal temperature T of the speed reduction mechanism 40 is performed, and the average drive torque Nav can be made less than the threshold value Nx. As a result, the lubrication state of the speed reduction mechanism 40 can be maintained in an appropriate state with low driving torque and high energy efficiency.

  (2) As the internal temperature T of the speed reduction mechanism 40 becomes higher, the amount of lubricating oil present in the internal space 40a of the speed reduction mechanism 40 becomes insufficient, and seizure occurs in the first gear 43, the second gear 44, and the like. The probability that is happening increases. In addition, when the amount of lubricating oil present in the internal space 40a of the speed reduction mechanism 40 is insufficient, the lubricity of the first gear 43 and the second gear 44 and the like decreases, and the average drive torque Nav of the speed reduction mechanism 40 also increases. To do.

  In the above embodiment, the high temperature side reference temperature TH is determined as a temperature at which seizure is occurring in the first gear 43 and the second gear 44 of the speed reduction mechanism 40. When the average drive torque Nav is equal to or higher than the threshold value Nx and the internal temperature T of the speed reduction mechanism 40 is equal to or higher than the high temperature side reference temperature TH, the lubricating oil is supplied to the internal space 40a of the speed reduction mechanism 40. increase. By increasing the supply of the lubricating oil in this way, it is possible to compensate for the shortage of the lubricating oil in the internal space 40a of the speed reduction mechanism 40 and to ensure appropriate lubricity in the first gear 43, the second gear 44, and the like. Moreover, the internal temperature T of the increased speed reduction mechanism 40 can be lowered by the newly supplied lubricating oil.

  (3) As the internal temperature T of the speed reduction mechanism 40 is lower, the lubricating oil present in the internal space 40a of the speed reduction mechanism 40 loses fluidity and increases in viscosity. When the viscosity of the lubricating oil increases, when the first gear 43 and the second gear 44 in the speed reduction mechanism 40 rotate, the lubricating oil becomes resistance and the average driving torque Nav of the speed reduction mechanism 40 increases.

  In the above-described embodiment, the low temperature side reference temperature TL is defined as a temperature at which the viscosity of the lubricating oil becomes equal to or higher than a certain value below that temperature. When the average driving torque Nav is equal to or higher than the threshold value Nx and the internal temperature T of the speed reduction mechanism 40 is lower than the low temperature side reference temperature TL, the electric heater 60 is switched on. Therefore, the temperature of the lubricating oil in the internal space 40a of the speed reduction mechanism 40 can be increased to decrease the viscosity. As a result, appropriate lubricity with good energy efficiency can be ensured when the average driving torque Nav is less than the threshold value Nx.

  (4) When the internal temperature T of the speed reduction mechanism 40 is equal to or higher than the low temperature side reference temperature TL and lower than the high temperature side reference temperature TH, it can be said that the internal temperature T of the speed reduction mechanism 40 is within an allowable range. Nevertheless, when the average driving torque Nav is equal to or greater than the threshold value Nx, for example, the first gear 43 and the second gear 44 of the speed reduction mechanism 40 are completely submerged in the lubricating oil. There is a possibility of being subject to resistance by

  In the above embodiment, in such a case, the amount of lubricating oil present in the internal space 40a is reduced by increasing the amount of lubricating oil discharged from the internal space 40a of the speed reduction mechanism 40. As a result, the resistance received by the first gear 43 and the second gear 44 of the speed reduction mechanism 40 from the lubricant is reduced, and the average driving torque Nav can be made less than the threshold value.

  (5) The internal space 40a of the speed reduction mechanism 40 of the above-described embodiment does not necessarily have a sealed structure, but when the internal space 40a has a sealed structure, the lubricating oil present in the internal space 40a of the speed reduction mechanism 40 It becomes difficult to confirm the amount directly. Further, in order to supply (supplement) lubricating oil to the internal space 40a of the speed reduction mechanism 40 having a sealed structure without depending on the lubricating oil supply device 50, large-scale maintenance such as disassembling the speed reduction mechanism 40 or each arm. Work may be required.

  In this regard, in the above embodiment, the supply of the lubricating oil is controlled based on the internal temperature T of the speed reduction mechanism 40 measured by the temperature sensor 46 and the average driving torque Nav when the second arm C4 turns. The amount of lubricating oil is automatically adjusted. That is, since it is not necessary for the operator to check the amount of lubricating oil present in the internal space 40a of the speed reduction mechanism 40, there is no problem even if a sealed structure is employed. Rather, since the temperature detected by the temperature sensor 46 is less affected by the outside air temperature, it is preferable to employ a sealed structure. In the above-described embodiment, the amount of lubricating oil present in the internal space 40 a of the speed reduction mechanism 40 is controlled via the discharge oil passage 51 and the supply oil passage 55 of the lubricating oil supply device 50. Therefore, in order to maintain the lubricity of the speed reduction mechanism 40, the large-scale maintenance work as described above is not required.

  (6) In the above-described embodiment, the lubricating oil discharged from the speed reduction mechanism 40 is supplied again to the speed reduction mechanism 40 via the discharged oil path 51, the lubricating oil tank 54, and the supply oil path 55. That is, the hydraulic circuit of the lubricating oil supply device 50 is a circulating oil passage through which the lubricating oil circulates. Therefore, it is possible to minimize the consumption amount of the lubricating oil by reusing the discharged lubricating oil.

  (7) As shown in steps ST31 to ST33 in the flowchart of FIG. 4, when the average drive torque Nav is still equal to or greater than the threshold value Nx even though the amount of discharged lubricant is increased, There is a possibility that foreign matter has entered the internal space 40a of the speed reduction mechanism 40 instead of a problem with the amount or temperature. In the above embodiment, a warning using the warning lamp 76 and the buzzer 77 is given under such a situation, so that the operator of the robot R can be urged to perform maintenance or the like.

(Example of change)
The above embodiment may be modified as follows. Moreover, you may apply combining each modification example suitably.

  -The structure of the deceleration mechanism 40 is not restricted to the structure of the said embodiment. For example, what is necessary is just to change suitably according to the shape of the 1st arm C3 and the 2nd arm C4, the reduction ratio calculated | required, etc. FIG. Further, the lubrication target mechanism of the lubricating oil supply device 50 is not limited to the speed reduction mechanism 40 interposed between the first arm C3 and the second arm C4. For example, a speed reduction mechanism interposed between the base C1 and the swivel base C2 and a speed reduction mechanism interposed between other arms may be used as the lubrication target mechanism.

  The configuration of the robot R is not limited to the configuration of the above embodiment. For example, an articulated robot R having 8 or more degrees of freedom may be used, or an articulated robot R having 6 or less degrees of freedom may be used. Further, the robot is not limited to the arc welding robot, and may be a transport robot that grips and transports an article or an inspection robot that photographs and inspects a predetermined portion of a workpiece. Further, for example, as long as a plurality of parts slide with each other such as a gear mechanism and a bearing mechanism, the mechanism to be lubricated is not limited to the mechanism constituting the robot R, and any device mechanism may be used. Can be adopted as

  In the above embodiment, the temperature sensor 46 is provided in the internal space 40a of the speed reduction mechanism 40, but the temperature sensor 46 may be provided in another place. For example, the outer surface of the gear housing 45, the inside of the first housing 11 in the first arm C3, and the inside of the second housing 21 in the second arm C4 are affected by the temperature of the internal space 40a of the speed reduction mechanism 40. Therefore, the temperature of the internal space 40a of the speed reduction mechanism 40 can be estimated by providing the temperature sensor 46 at these locations and measuring the temperature. Even in such a case, it can be said that the temperature sensor 46 indirectly measures the temperature of the internal space 40 a of the speed reduction mechanism 40.

  In the above embodiment, the main control unit 71 of the robot control device RC also functions as the control unit of the lubricant supply device 50. However, the control unit of the lubricant supply device 50 is separate from the robot control device RC. May be configured.

  -In the lubricating oil supply apparatus 50, an oil path does not need to circulate. That is, the lubricating oil discharged from the internal space 40 a of the speed reduction mechanism 40 may be discarded as it is after being stored in the lubricating oil tank 54.

  In the lubricating oil supply device 50, an opening / closing valve that takes two positions of zero or full opening may be employed as the discharge valve 52 instead of a flow rate control valve whose opening is adjustable. In this case, the amount of lubricating oil discharged from the internal space 40a of the speed reduction mechanism 40 is adjusted by controlling the opening time of the on-off valve. In addition, any valve can be adopted as the discharge valve 52 as long as it can adjust the amount of lubricating oil discharged from the internal space 40a of the speed reduction mechanism 40. This also applies to the supply valve 59.

  In the lubricating oil supply device 50, a discharge pump may be provided in the discharge oil passage 51, and the lubricating oil in the internal space 40a of the speed reduction mechanism 40 may be discharged by the negative pressure generated by the discharge pump. In this case, the amount of lubricating oil discharged from the internal space 40a of the speed reduction mechanism 40 can be adjusted by omitting the discharge valve 52 and controlling the drive of the discharge pump.

  The supply valve 59 may be omitted from the lubricating oil supply device 50. In this case, the amount of lubricating oil supplied to the internal space 40a of the speed reduction mechanism 40 can be adjusted by controlling the hydraulic pressure generated by the pump 56 by controlling the rotational speed of the electric motor 57 and the like. In this case, the supply oil passage 55 and the pump 56 function as a supply unit that supplies lubricating oil to the internal space 40 a of the speed reduction mechanism 40.

  In the above embodiment, the electric heater 60 is disposed adjacent to the supply oil passage 55, but may be disposed adjacent to the discharge oil passage 51 and the lubricating oil tank 54. Further, the electric heater 60 may be disposed in the internal space 40 a of the speed reduction mechanism 40. For example, a heat exchanger in which a high-temperature heat medium is circulated may be employed as a temperature adjustment unit that adjusts the temperature of the lubricating oil, without being limited to the electric heater 60.

  In the above embodiment, the servo amplifier 75 of the robot controller RC calculates the average drive torque Nav, but the main control unit 71 may calculate the average drive torque Nav. In this case, the servo amplifier 75 outputs the amount of power required to rotate the second arm C4 by a unit angle as a drive torque to the main control unit 71, and the main control unit 71 converts the input drive torque into a plurality of input drive torques. Based on this, the average driving torque Nav is calculated. Further, the threshold value may be compared with the driving torque required for causing the second arm C4 to perform the unit angle turning operation without calculating the average driving torque Nav.

  The low temperature side reference temperature TL and the high temperature side reference temperature TH are not limited to the temperatures exemplified in the above embodiment. These reference temperatures may be determined by comprehensively considering the configuration of the speed reduction mechanism 40, the speed assumed as the turning speed of the second arm C4, the physical properties of the lubricating oil, the environment in which the robot R is installed, and the like.

  When the internal temperature T of the speed reduction mechanism 40 is equal to or higher than the high temperature side reference temperature TH, the opening degree of the supply valve 59 of the lubricating oil supply device 50 may be set larger as the internal temperature T is higher. In this case, the higher the internal temperature T, the easier it is to obtain the effect of lowering the internal temperature T of the speed reduction mechanism 40 by the supplied lubricating oil.

  In the above embodiment, in increasing the amount of lubricating oil supplied to the internal space 40a of the speed reduction mechanism 40 (step ST12 shown in FIG. 4), the opening degree of the supply valve 59 of the lubricating oil supply device 50 is increased. Simultaneously with this processing, the discharge valve 52 may be closed. By closing the discharge valve 52, the amount of lubricating oil present in the internal space 40a of the speed reduction mechanism 40 can be increased more quickly.

  In the above embodiment, the control for increasing the amount of lubricating oil supplied to the internal space 40a of the speed reduction mechanism 40 may be repeated a plurality of times. Specifically, for example, after the amount of lubricating oil supplied to the internal space 40a of the speed reduction mechanism 40 is increased, when the internal temperature T of the speed reduction mechanism 40 is equal to or higher than the high-temperature side reference temperature TH, the speed reduction mechanism again. The amount of lubricating oil supplied to the internal space 40a of the 40 is increased. Then, even if the control for increasing the amount of the lubricating oil is performed a predetermined number of times, a warning is issued when the internal temperature T of the speed reduction mechanism 40 is still higher than the high temperature side reference temperature TH (step ST14).

  In increasing the amount of lubricating oil supplied to the internal space 40a of the speed reduction mechanism 40 (step ST12 shown in FIG. 4), the opening degree of the discharge valve 52 is simultaneously increased while the opening degree of the supply valve 59 is increased. Also good. If the increase amount of the lubricating oil supply amount due to the increase in the opening degree of the supply valve 59 exceeds the increase amount of the lubricant oil discharge amount due to the increase in the opening amount of the discharge valve 52, the reduction mechanism 40 The amount of lubricating oil present in the internal space 40a increases. In the case of this modified example, the lubricating oil whose temperature has risen is quickly discharged from the internal space 40a of the speed reduction mechanism 40, and a lot of lubricating oil is newly supplied to the internal space 40a of the speed reduction mechanism 40. The internal temperature T of the mechanism 40 can be lowered more quickly.

  In the above embodiment, the opening amount of the discharge valve 52 of the lubricant supply device 50 is increased in reducing the amount of lubricant discharged from the internal space 40a of the speed reduction mechanism 40 (step ST31 shown in FIG. 4). The supply valve 59 may be closed simultaneously with this processing. By closing the supply valve 59, the amount of lubricating oil present in the internal space 40a of the speed reduction mechanism 40 can be reduced more quickly.

  In the above embodiment, the control for reducing the amount of lubricating oil supplied to the internal space 40a of the speed reduction mechanism 40 may be repeated a plurality of times. Specifically, for example, after the amount of lubricating oil supplied to the internal space 40a of the speed reduction mechanism 40 is reduced, when the average drive torque Nav is equal to or greater than the threshold value Nx, the internal space of the speed reduction mechanism 40 is again displayed. The amount of lubricating oil supplied to 40a is reduced. Then, even if the control for reducing the amount of the lubricating oil is performed a predetermined number of times, a warning is issued if the average driving torque Nav is still equal to or greater than the threshold value Nx (step ST33).

  In increasing the amount of lubricating oil discharged from the internal space 40a of the speed reduction mechanism 40 (step ST31 shown in FIG. 4), while increasing the opening degree of the discharge valve 52, the opening degree of the supply valve 59 is also increased simultaneously. Also good. If the increase amount of the lubricating oil discharge amount due to the increase in the opening degree of the discharge valve 52 exceeds the increase amount of the lubricating oil supply amount due to the increase in the opening amount of the supply valve 59, the reduction mechanism 40 The amount of lubricating oil present in the internal space 40a decreases.

  In the above embodiment, the electric heater 60 is turned on when the internal temperature T of the speed reduction mechanism 40 is lower than the low temperature side reference temperature TL (step ST22 shown in FIG. 4), but this process is omitted. Also good. As the second arm C4 rotates, the internal temperature T of the speed reduction mechanism 40 increases due to frictional heat and the like. Therefore, even if the electric heater 60 is not turned on, the internal temperature T of the speed reduction mechanism 40 can be equal to or higher than the low-temperature side reference temperature TL if the second arm C4 is turned. However, the time until the internal temperature T becomes equal to or higher than the low temperature side reference temperature TL is faster when the electric heater 60 is turned on than when the electric heater 60 is turned off. When the process of turning on the electric heater 60 is omitted, the electric heater 60 itself can be omitted.

  -A series of processing (step ST31 to step ST33) when the internal temperature T of the speed reduction mechanism 40 in the above embodiment is equal to or higher than the low temperature side reference temperature TL and lower than the high temperature side reference temperature TH is omitted depending on the configuration of the lubrication target mechanism. it can. For example, if the gear or the bearing is a lubrication target mechanism that cannot be submerged in the lubricating oil, it is unlikely that the drive torque is reduced by the process of step ST32 of the above embodiment. Therefore, in the case of the lubrication target mechanism having such a configuration, it is not necessary to perform a series of processes in steps ST31 to ST33.

  R ... Robot, C1 ... Base, C2 ... Swivel base, C3 ... First arm, C4 ... Second arm, C5 ... Third arm, C6 ... Fourth arm, C7 ... Fifth arm, C8 ... Tool fixing member, DESCRIPTION OF SYMBOLS 40 ... Reduction mechanism, 40a ... Internal space, 43 ... 1st gear, 44 ... 2nd gear, 45 ... Gear housing, 46 ... Temperature sensor, 50 ... Lubricating oil supply apparatus, 51 ... Drain oil path, 52 ... Drain valve, 55 ... Supply oil passage, 56 ... Pump, 59 ... Supply valve, 60 ... Electric heater, RC ... Robot controller, 71 ... Main controller.

Claims (4)

A supply unit for supplying lubricating oil into the lubrication target mechanism;
A discharge part for discharging lubricating oil from the inside of the lubrication target mechanism;
A temperature detector for detecting an internal temperature of the lubrication target mechanism;
A drive unit that receives a drive torque signal indicating a drive torque when driving the lubrication target mechanism,
When the drive torque indicated by the input drive torque signal is equal to or greater than a threshold value, the control unit controls at least one of the supply unit and the discharge unit according to the internal temperature detected by the temperature detection unit. A lubricating oil supply device that adjusts the amount of lubricating oil inside the lubrication target mechanism by controlling. A temperature adjustment unit for adjusting the temperature of the lubricating oil inside the lubrication target mechanism;
In the case where the drive torque indicated by the input drive torque signal is equal to or greater than a threshold value and the internal temperature detected by the temperature detector is lower than a first reference temperature at which the temperature of the lubricating oil needs to be increased. The lubricating oil supply device according to claim 1, wherein the temperature control unit is controlled such that the temperature of the lubricating oil supplied to the inside of the lubrication target mechanism increases. The control unit is configured such that the driving torque indicated by the input driving torque signal is equal to or higher than a threshold value, and the internal temperature detected by the temperature detecting unit is equal to or higher than a second reference temperature higher than the first reference temperature. 3. In some cases, at least one of the supply unit and the discharge unit is controlled so that the amount of lubricating oil inside the lubrication target mechanism increases. The control unit is configured such that a driving torque indicated by the driving torque signal is equal to or higher than a threshold value, and an internal temperature detected by the temperature detecting unit is equal to or higher than the first reference temperature and higher than the first reference temperature. The lubrication according to claim 2 or 3, wherein when the temperature is lower than a reference temperature, the supply unit or the discharge unit is controlled so that the amount of lubricating oil inside the lubrication target mechanism decreases. Oil supply device.