Robot

Abstract

A lubricant container portion (7) is provided in a drive portion (5) of a robot arm including a first arm (2, 2a) and a second arm (3, 3a) that are relatively displaced by a speed reduction mechanism (4). A receiving member (9, 9a) is provided below a liquid surface (8) of a lubricant (6) within the lubricant container portion (7). The receiving member (9, 9a) has a concave portion (10) that is concave upward in the vertical direction. Thus, even after a lapse of time since the robot has stopped, lubricant can be collected from the receiving member (9, 9a) in a state suitable for observing iron powder contained in the lubricant (6).

Description

Technical Field

[0001] The present invention relates to robots such as industrial robots. Background Art

[0002] In a speed reduction mechanism of a joint portion of a robot, lubricants such as grease and lubricating oil are used. It is known that there is a correlative relationship between the properties and the content state of iron powder contained in such lubricants and the degree of wear of the speed reduction mechanism. Therefore, the following operations are performed: Based on the properties and the content state of iron powder in the lubricant, internal breakage and other wear states of the speed reduction mechanism are diagnosed. When observing the size and concentration of iron powder contained in the lubricant for the purpose of such diagnosis, an operation of extracting a certain amount of the lubricant is performed. In addition, various proposals have been made to address problems regarding the lubricant used in the speed reduction mechanism. For example, there is a proposed technique: preventing the lubricant from leaking to the outside even when the lubricant thermally expands in the lubrication chamber and the lubrication chamber deforms due to contact or collision with other objects (for example, refer to Patent Document 1). In addition, there is a proposed technique: extending the period for replacing the lubricant of the speed reduction mechanism to improve the operation rate of the robot (for example, refer to Patent Document 2). In addition, there is a proposed technique: adjusting the amount of the lubricant dripping onto the lubricating oil receiving member by utilizing the temperature dependence of the lubricant viscosity, allowing a higher-temperature and lower-viscosity lubricant to flow through a longer lubricating oil flow path, thereby promoting cooling and maintaining the temperature of the lubricant within a specified range (for example, refer to Patent Document 3).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-34383

[0006] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2020-41562

[0007] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2015-161234 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] However, for the purpose of diagnosing the wear state of the reduction mechanism by observing the properties and content of iron powder and the like in the lubricant, it is desirable to collect the lubricant when the concentration distribution of iron powder and the like in the lubrication chamber is uniform. The iron powder in the lubricant is stirred due to the rotation and swing of reduction mechanism elements such as gears and reducers during the operation of the robot, and the concentration distribution is likely to become relatively uniform. On the other hand, when collecting the lubricant, the staff needs to approach the robot, so generally the robot needs to be stopped. If the robot stops, the iron powder settles in the lubrication chamber under the action of gravity. Therefore, if a certain amount of time has passed after the robot stops, even if the lubricant is collected from the lubrication chamber, the distribution state of the iron powder in the lubricant cannot be accurately grasped. Especially in the case of a lubricant with a relatively low viscosity such as lubricating oil, compared with a lubricant with a relatively high viscosity such as grease, the settling speed of the iron powder is faster, and the time available for collecting for suitable observation is limited. In addition, since the iron powder deposits at the lower part of the lubrication chamber, it is difficult to collect at the position where the iron powder deposits for the normal collection operation of the lubricant, such as collecting from the liquid surface of the lubricant in the lubrication chamber.

[0010] Therefore, it is desirable that even after a period of time has passed since the robot stopped, the lubricant can be collected in a manner suitable for observing the state of the iron powder contained in the lubricant.

[0011] Solution to the problem

[0012] One technical solution of the robot of the present disclosure is configured to include: a lubricant container portion provided in the drive portion of the robot arm for accommodating the lubricant, and the drive portion of the robot arm makes the first arm and the second arm displace relative to each other by means of a reduction mechanism sandwiched between the first arm and the second arm; and a receiving member provided below the liquid surface of the lubricant in the lubricant container portion, and the receiving member has a concave portion that is concave upward in the vertical direction.

[0013] Effect of the invention

[0014] According to one technical solution, even after a period of time has passed since the robot stopped, the lubricant can be collected from the receiving member in a manner suitable for observing the distribution state of the iron powder. Description of the drawings

[0015] Figure 1 It is a cross-sectional view showing the reduction mechanism and the lubricant container portion of the robot of the present disclosure.

[0016] Figure 2 It is from Figure 1 A view showing the situation of collecting the iron powder accumulated in the receiving member from the lubricant container portion of the robot as observed from one arm side.

[0017] Figure 3 It is with Figure 1The same perspective shows a diagram of the situation where iron powder accumulated in the receiving member is collected from the lubricant container portion of the robot.

[0018] Figure 4 It is a diagram showing the relationship between the posture of one arm of the robot according to another aspect of the present disclosure and the recess of the receiving member.

[0019] Figure 5 It is shown in side view Figure 4 of the cross-sectional view.

[0020] Figure 6 It shows Figure 4 a diagram of the situation where one arm of the robot has swung. Detailed implementation mode

[0021] Figure 1 It is a cross-sectional view showing the speed reduction mechanism and the lubricant container portion of the robot of the present disclosure.

[0022] In Figure 1 , the illustrated part of the robot 1 constitutes the drive portion 5 of the robot arm. The drive portion 5 of the robot arm relatively displaces the first arm 2 and the second arm 3 by means of a speed reduction mechanism 4 clamped between the first arm 2 and the second arm 3. In the speed reduction mechanism 4, there is provided a cylindrical lubricant container portion 7 for accommodating the lubricant 6 to a prescribed liquid level. At a position below the liquid surface 8 of the lubricant 6 in the lubricant container portion 7, there is provided a receiving member 9 for receiving and accumulating iron powder distributed in the lubricant 6. The receiving member 9 has a recess 10 that is concave upward in the vertical direction. In addition, even when the first arm 2 and the second arm 3 relatively displace, the relative position between the first arm 2 and the lubricant container portion 7 does not change.

[0023] Iron powder is generated when elements such as gears and speed reducers (not shown) that are elements of the speed reduction mechanism 4 are worn due to friction, is suspended in the lubricant 6, and is stirred by the operation of the elements of the speed reduction mechanism 4 during the operation of the robot 1. As a result, the iron powder in the lubricant 6 exhibits a distribution with a concentration close to being homogeneous. At this time, a part of the iron powder that reaches above the recess 10 of the receiving member 9 gradually accumulates on the receiving member 9 (its recess 10). On the other hand, when the robot 1 stops, the iron powder does not diffuse and settles in the lubricant container portion 7 under the action of gravity. Then, in Figure 1 , with reference to Figure 2 and Figure 3 , a structure for collecting the iron powder accumulated in the recess 10 of the receiving member 9 will be described.

[0024] Figure 2 and Figure 3 are diagrams showing the situation where iron powder accumulated in the receiving member 9 is collected from the lubricant container portion 7 of the robot 1. Figure 2FIG. 0 is a side view of the periphery of the speed reduction mechanism 4 of the robot 1 from the second side of the first arm 2. Figure 3 FIG. Figure 1 is a view showing the same perspective. In Figure 2 and Figure 3 the parts corresponding to Figure 1 are denoted by the same reference numerals. In the lubricant container portion 7, a collection port 11 is provided for collecting iron powder accumulated in the recess 10 of the receiving member 9. In this case, the collection port 11 also serves as a supply / discharge port for supplying or discharging the lubricant 6 with respect to the lubricant container portion 7. The collection port 11 is provided at a position above the liquid level 8 of the lubricant 6. In the side view of Figure 2 the receiving member 9 is disposed vertically below the collection port 11 serving as the supply / discharge port. In this example, the central position in the left-right direction in the side view of Figure 2 of the recess 10 of the receiving member 9 is vertically below the center of the collection port 11 serving as the supply / discharge port. A communication hole 12 is formed in the first arm 2 leading from the outside to the collection port 11 of the lubricant container portion 7.

[0025] When collecting the iron powder accumulated in the receiving member 9, a tube 13 for collecting iron powder is inserted through the communication hole 12 of the first arm 2 from the collection port 11 of the lubricant container portion 7 toward the receiving member 9 located vertically below it. Since the receiving member 9 is located vertically below the collection port 11 of the lubricant container portion 7, the tip 14 of the tube 13 can be easily inserted to a position close to the bottom of the recess 10 of the receiving member 9. In the state where the tip 14 of the tube 13 is inserted in this way, a suction member such as a sample collection syringe is used to collect the iron powder accumulated in the recess 10 of the receiving member 9 together with the lubricant 6. For the iron powder collected together with the lubricant 6 in this way, the distribution concentration, size, and other characteristics are analyzed, so that the degree of wear of the speed reduction mechanism 4 of the robot 1 can be inferred.

[0026] Figures 4 to 6 FIG. Figures 4 to 6 The robot 1a of Figures 1 to 3 has a first arm 2a and a second arm 3a corresponding to the first arm 2 and the second arm 3 of the robot 1 of Figures 4 to 6 In the disclosed embodiment, the lubricant container portion 7 swings integrally with the first arm 2a. Figure 4 FIG. Figure 5 is a view showing the relationship between the posture of the first arm 2a of the robot 1a of another embodiment of the present disclosure and the recess 10 of the receiving member 9a as viewed from the first arm 2a side. Figure 4 is a cross-sectional view shown in side view of Figure 6 FIG. Figure 4 shows the state where the first arm 2a of Figures 4 to 6 has swung. In Figures 1 to 3The corresponding parts are shown with the same reference numerals. Additionally, in Figures 4 to 6 state, a lid 15 is fitted in the communication hole 12 leading to the collection port 11.

[0027] Figure 4 and Figure 5 shows a case where the central axis L in the longitudinal direction of the first arm 2a is aligned with the imaginary axis V in the vertical direction. The recess 10 of the receiving member 9a in the cylindrical lubricant container portion 7 of the robot 1a has a valley shape in the form of the letter V in which the inclined surfaces 10a symmetrically rise from the central valley bottom portion 10b in a side sectional view. When the first arm 2a is in Figure 4 this posture, the position of the valley bottom portion 10b of the recess 10 as seen from a direction perpendicular to the paper surface is aligned with the above-described central axis L (and thus the imaginary axis V). The inclined surfaces 10a on both sides of the recess 10 are inclined at an inclination angle θ with respect to the horizontal plane H that is in contact with the valley bottom portion 10b and rise symmetrically with respect to the central axis L.

[0028] When the first arm 2a is in the above-described Figure 4 and Figure 5 postures, the entire recess 10 of the receiving member 9a is submerged below the liquid level 8 of the lubricant 6. When the first arm 2a swings within the range of the rotation angle corresponding to the above-described inclination angle θ from the above-described Figure 4 and Figure 5 postures, the inclined surfaces 10a of the recess 10 do not incline downward more than the horizontal plane H. Therefore, the iron powder temporarily collected in the recess 10 of the receiving member 9a hardly overflows from the recess 10.

[0029] Figure 6 shows a case where the first arm 2a has swung by the maximum swing angle Φ. Here, the maximum swing angle Φ is the maximum value of the swing angle, which is the angle formed by the central axis L in the longitudinal direction of the first arm 2a and the imaginary axis V in the vertical direction. When the robot 1a continuously performs normal work, the first arm 2a repeatedly swings within the angular range up to the maximum swing angle Φ shown in the figure. The maximum swing angle Φ is greater than the inclination angle θ of the two inclined surfaces 10a of the above-described recess 10. That is, the inclination angle θ is smaller than the maximum swing angle Φ. The maximum swing angle Φ is, for example, about 100 degrees.

[0030] Regarding the relationship between the above-described inclination angle θ and the maximum swing angle Φ, it can be summarized as follows. That is, the recess 10 has inclined surfaces 10a that symmetrically rise in the form of the letter V from the central valley bottom portion 10b, and the inclination angle θ of the inclined surfaces 10a with respect to the horizontal plane H when the longitudinal direction (central axis L in the longitudinal direction) of the first arm 2a itself becomes the vertical direction (aligned with the imaginary axis V in the vertical direction) and the swing angle is 0 is an angle smaller than the maximum swing angle Φ when the first arm 2a swings.

[0031] When the first arm 2a swings to the maximum swing angle Φ, the inclined surface 10a of the recess 10 is inclined downward with respect to the horizontal plane H( Figure 4 ). Therefore, the iron powder temporarily collected in the recess 10 of the receiving member 9a overflows from the recess 10 and falls under the action of its own weight. The first arm 2a repeatedly swings within the angular range reaching the maximum swing angle Φ, so that the iron powder temporarily collected in the recess 10 of the receiving member 9a overflows from the recess 10 and falls each time it swings. Thus, during the operation of the robot 1a, the iron powder in the lubricant 6 does not accumulate in the recess 10 of the receiving member 9a. Therefore, when the robot 1a is stopped and Figure 2 and Figure 3 similarly collecting the iron powder accumulated in the recess 10 of the receiving member 9a, the iron powder distributed in the lubricant 6 just before collection is collected. Thus, by analyzing the distribution concentration, size, and other properties of the iron powder that truthfully reflect the degree of wear of the reduction gear mechanism 4 at the collection moment, it is possible to infer with relatively high accuracy the degree of wear of the reduction gear mechanism 4 of the robot 1a.

[0032] As described above, the effects of the robot of the present disclosure described with reference to Figures 1 to 6 are summarized as follows.

[0033] (1) The robots 1 and 1a of the present disclosure include: a lubricant container portion 7 provided in the drive portion 5 of the robot arm for containing a lubricant 6, and the drive portion 5 of the robot arm relatively displaces the first arm 2, 2a and the second arm 3, 3a by means of a reduction gear mechanism 4 sandwiched between the first arm 2, 2a and the second arm 3, 3a; and receiving members 9, 9a provided below the liquid level 8 of the lubricant 6 in the lubricant container portion 7, and the receiving members 9, 9a have recesses 10 that are concave upward in the vertical direction.

[0034] In the robot of the above (1), even after a certain period of time has passed after the robots 1 and 1a stop, the iron powder collected in the receiving members 9 and 9a does not settle to the bottom of the lubricant container portion 7, and the iron powder collected in the receiving members 9 and 9a can be collected together with the lubricant 6. Thus, for the iron powder collected together with the lubricant 6, by analyzing the distribution concentration, size, and other properties, it is possible to infer the degree of wear of the reduction gear mechanism 4 of the robots 1 and 1a.

[0035] (2) In the robots 1 and 1a of the present disclosure, in one form, the receiving members 9 and 9a are arranged vertically below the collection port (supply and discharge port) 11, and the collection port (supply and discharge port) 11 is provided at a position above the liquid level 8 of the lubricant 6 to supply or discharge the lubricant 6 with respect to the lubricant container portion 7.

[0036] In the robots 1 and 1a in the above (2), since the receiving member 9 is located vertically below the collection port 11 of the lubricant container portion 7, the front end 14 of the tube 13 for collecting iron powder can be easily inserted into a position close to the bottom of the recess 10 of the receiving member 9. In the state where the front end 14 of the tube 13 is inserted like this, it is possible to collect the iron powder accumulated in the recess 10 of the receiving member 9 together with the lubricant 6 using a suction member such as a sample collection syringe.

[0037] (3) In the robot 1a of the present disclosure, the receiving member 9a is configured to swing together with the first arm 2a, which is at least one of the corresponding arms of the first arm 2a and the second arm 3a. When the receiving member 9a is displaced in conjunction with the swing of the first arm 2a, the iron powder temporarily accumulated in the recess 10 falls into the lubricant container portion 7.

[0038] In the robot 1a in the above (3), during operation, the iron powder in the lubricant 6 does not accumulate in the recess 10 of the receiving member 9a. Therefore, when the robot 1a is stopped and the iron powder accumulated in the recess 10 of the receiving member 9a is collected, the iron powder distributed in the lubricant 6 immediately before collection is collected. Thus, by analyzing the distribution concentration, size, and other properties of the iron powder that truthfully reflect the degree of wear of the reduction gear mechanism 4 at the collection time, it is possible to infer the degree of wear of the reduction gear mechanism 4 of the robot 1a with high accuracy.

[0039] (4) For the robot 1a of the present disclosure, the recess 10 has inclined surfaces 10a that stand up symmetrically in a V-shaped valley shape from the central valley bottom portion 10b. The inclination angle θ of the inclined surface 10a with respect to the horizontal plane H when the swing angle of the first arm 2a with respect to the vertical direction is 0 is smaller than the maximum swing angle Φ of the first arm with respect to the vertical direction.

[0040] In the robot 1a in the above (4), the first arm 2a repeatedly swings within an angular range up to the maximum swing angle Φ, so that the iron powder temporarily collected in the recess 10 of the receiving member 9a overflows from the recess 10 and falls each time it swings. Thus, during operation of the robot 1a, the iron powder in the lubricant 6 does not accumulate in the recess 10 of the receiving member 9a. Therefore, when the robot 1a is stopped and the iron powder accumulated in the recess 10 of the receiving member 9a is collected, the iron powder distributed in the lubricant 6 immediately before collection is collected. Thus, by analyzing the distribution concentration, size, and other properties of the iron powder that truthfully reflect the degree of wear of the reduction gear mechanism 4 at the collection time, it is possible to infer the degree of wear of the reduction gear mechanism 4 of the robot 1a with high accuracy.

[0041] In addition, the present disclosure is not limited to the above-described embodiments and can be implemented with various modifications and changes. For example, in the above-described embodiments, lubricating oil, grease, etc. can also be used as the lubricant. Further, in the robot 1a, the receiving member 9a is configured to swing together with the first arm 2a, but in the case of a robot having a structure in which the second arm 3a swings, the receiving member 9a can also be configured to swing together with the second arm 3a.

[0042] In addition, within the scope where the same receiving member and the like are provided for the lubricant container of a speed reduction mechanism other than a robot and other devices that operate with friction of accompanying machinery, modifications and improvements that can achieve the object of the present disclosure are also included in the present disclosure.

[0043] Description of Reference Numerals

[0044] 1, 1a, robot; 2, 2a, first arm; 3, 3a, second arm; 4, speed reduction mechanism; 5, drive unit; 6, lubricant; 7, lubricant container unit; 8, liquid level; 9, 9a, receiving member; 10, recess; 10a, inclined surface; 10b, bottom of valley; 11, collection port (supply / discharge port); 12, communication hole; 13, pipe; 14, front end; 15, lid.

Claims

1. A robot, wherein, the robot includes: a lubricant container portion provided in a drive portion of a robot arm for accommodating a lubricant, the drive portion of the robot arm causing relative displacement of the first arm and the second arm by means of a speed reduction mechanism sandwiched between the first arm and the second arm; and a receiving member provided below the liquid level of the lubricant in the lubricant container portion, the receiving member having a concave portion that is concave upward in the vertical direction, the receiving member is configured to swing together with at least one of the first arm and the second arm, and when the receiving member is displaced in conjunction with the swing of the corresponding arm, iron powder temporarily accumulated in the concave portion falls into the lubricant container portion.

2. The robot according to claim 1, wherein, the receiving member is disposed vertically below a supply and discharge port provided at a position above the liquid level to supply or discharge the lubricant with respect to the lubricant container portion.

3. The robot according to claim 1 or 2, wherein, the concave portion has inclined surfaces that rise symmetrically in a V-shaped valley shape from a central valley bottom, the inclination angle of the inclined surface with respect to the horizontal plane when the swing angle of the corresponding arm with respect to the vertical direction is 0 is less than the maximum swing angle of the corresponding arm with respect to the vertical direction.

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