Patent Publication Number: US-9406173-B2

Title: Maintenance information output apparatus and maintenance information output system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of co-pending U.S. patent application Ser. No. 12/090,926 filed Mar. 6, 2009, which, in turn, is a Section 371 of International Application No. PCT/JP2006/320967, filed Oct. 20, 2006, which was published in the Japanese language on Apr. 26, 2007, under International Publication No. WO 2007/046505 A1. The entire disclosures of each of these prior applications are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to a maintenance information output apparatus which outputs maintenance information of a speed reducer used in an industrial robot, a machine tool, or the like. 
     2. Background Art 
     As a conventional maintenance information output apparatus, known is an apparatus in which the life of a speed reducer is calculated and accumulated at each sampling time from the generated torque, number of rotations, and accumulated operation time of a servo motor for driving a robot manipulator of an industrial robot, and, when the accumulated value exceeds a predetermined reference value, the need for inspection or replacement of the speed reducer is displayed (for example, see Patent Reference 1). 
     Patent Reference 1: JP-A-7-124889 (pages 2 and 3, FIGS. 1 and 2) 
     DISCLOSURE OF THE INVENTION 
     Problems that the Invention is to Solve 
     In a conventional maintenance information output apparatus, however, influences on the life of a speed reducer due to causes other than the generated torque, number of rotations, and accumulated operation time of a servo motor, such as those on the life of a speed reducer due to the atmosphere temperature, a lubrication failure in the speed reducer, assembly mismatching, deformation of a member, and the like are not considered, and the life of the speed reducer is predicted only on the basis of the generated torque, number of rotations, and accumulated operation time of the servo motor. Therefore, there is a problem in that maintenance information of a speed reducer used in an industrial robot is sometimes inadequate. 
     In a conventional maintenance information output apparatus, for example, there is a case that the need for inspection or replacement of a speed reducer is not displayed in spite that the speed reducer is actually at the end of the life, or the need for inspection or replacement of a speed reducer is displayed although the speed reducer is not actually at the end of the life. 
     The invention has been conducted in order to solve the problem of the conventional art. It is an object of the invention to provide a maintenance information output apparatus which can output maintenance information of a speed reducer used in an industrial robot, more adequately than the conventional art. 
     Means for Solving the Problems 
     The maintenance information output apparatus of the invention comprises: an outputting portion which outputs maintenance information of a speed reducer; and a controlling portion which, when an amount of iron in a lubricant in the speed reducer is equal to or larger than a threshold value, causes the outputting portion to output the maintenance information. 
     According to the configuration, on the basis of the amount of iron which is actually produced in the lubricant in the speed reducer as a result of wear of the speed reducer, the maintenance information output apparatus of the invention outputs maintenance information of the speed reducer. Therefore, the apparatus can output maintenance information of the speed reducer, more adequately than the conventional art. 
     In the maintenance information output apparatus of the invention, furthermore, the threshold value is disposed in plural steps, and the maintenance information is disposed in plural steps in accordance with the steps of the threshold value. 
     According to the configuration, the maintenance information output apparatus of the invention can allow the user to perform stepwise maintenance. 
     The maintenance information output system of the invention wherein the system comprises: an iron amount detecting device which is attached to a speed reducer, and which detects an amount of iron in a lubricant in the speed reducer; a receiver which receives data of the amount of iron detected by the iron amount detecting device; and a maintenance information output apparatus having an outputting portion which outputs maintenance information of the speed reducer, and the maintenance information output apparatus has: a receiving portion which receives the data from the receiver; and a controlling portion which, when the amount of iron is equal to or larger than a threshold value, causes the outputting portion to output the maintenance information. 
     According to the configuration, on the basis of the amount of iron which is actually produced in the lubricant in the speed reducer as a result of wear of the speed reducer, the maintenance information output system of the invention outputs maintenance information of the speed reducer. Therefore, the system can output maintenance information of the speed reducer, more adequately than the conventional art. 
     The maintenance information output method of the invention has a configuration in which an amount of iron in a lubricant in a speed reducer is detected, and, when the amount of iron is equal to or larger than a threshold value, maintenance information of the speed reducer is output. 
     According to the configuration, in the maintenance information output method of the invention, on the basis of the amount of iron which is actually produced in the lubricant in the speed reducer as a result of wear of the speed reducer, maintenance information of the speed reducer is output. Therefore, the method can output maintenance information of the speed reducer, more adequately than the conventional art. 
     Effect of the Invention 
     The invention can provide a maintenance information output apparatus which can output maintenance information of a speed reducer more adequately than the prior art. 
     The eccentric oscillation speed reducer of the invention wherein the speed reducer comprises: a first member having internal teeth; an external tooth member which has external teeth meshing with the internal teeth, which is engaged with a crankshaft, and which eccentrically oscillates; and a second member which is engaged with the external tooth member, and which is rotatable with respect the first member, 
     the crankshaft and the external tooth member are housed in a space formed by the first member and the second member, and 
     the speed reducer comprises an iron amount detecting device which is attached to at least one of the first member and the second member, and which detects an amount of iron in a lubricant in the space. 
     According to the configuration, the eccentric oscillation speed reducer of the invention can detect the amount of iron which is actually produced in the lubricant in the speed reducer as a result of wear of the speed reducer. On the basis of the detected amount of iron, maintenance information of the speed reducer is output. Therefore, maintenance information of the speed reducer can be output more adequately than the conventional art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view of a maintenance information output system of an embodiment of the invention. 
         FIG. 2A  is a section view of an eccentric oscillation speed reducer to which an iron amount detecting device of the maintenance information output system shown in  FIG. 1  is attached. 
         FIG. 2B  is a section view of a portion in the vicinity of the iron amount detecting device in the speed reducer to which the iron amount detecting device of the maintenance information output system shown in  FIG. 1  is attached. 
         FIG. 3  is a block diagram of the iron amount detecting device of the maintenance information output system shown in  FIG. 1 . 
         FIG. 4  is a block diagram of a portable wireless receiver of the maintenance information output system shown in  FIG. 1 . 
         FIG. 5  is a block diagram of a maintenance information output apparatus of the maintenance information output system shown in  FIG. 1 . 
         FIG. 6  is a view showing a time series change of an amount of iron in a lubricant in the speed reducer. 
         FIG. 7  is a flowchart of a data analysis process of the maintenance information output apparatus shown in  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Best Mode for Carrying Out the Invention 
     Hereinafter, an embodiment of the invention will be described with reference to the drawings. 
     First, the structure of a maintenance information output system of the embodiment will be described. 
     As shown in  FIG. 1 , the maintenance information output system  100  comprises: iron amount detecting devices  110  (see  FIG. 2B ) which are attached respectively to plural eccentric oscillation speed reducers  20  used in rotation transmitting portions of an industrial robot  10  placed in a production line, and which detect the amount of iron in a lubricant  20   a  (see  FIG. 2B ) in the speed reducers  20 ; a portable wireless receiver  120  which wirelessly receives data of the amounts of iron detected by the iron amount detecting devices  110 ; and a maintenance information output apparatus  130  which is a computer that is placed in a maintenance room separated from the production line, and that outputs maintenance information of the speed reducers  20 . 
     For example, the eccentric oscillation speed reducer  20  shown in  FIG. 2A  is attached to a joint portion of the robot  10 , and comprises: a one-side member  12   a  which constitutes the joint portion of the robot  10 ; an internal tooth member  21  which is fixed to the one-side member  12   a  by bolts, and which has internal teeth on the inner circumference; two external tooth members  24  each of which has external teeth meshing with the internal teeth, and which are engaged with a crankshaft  23  to eccentrically oscillate; a member  12   b  which constitutes another side of the joint portion of the robot  10 ; and a support member  22  which is fixed to the other member  12   b  by bolts, and which is engaged with the crankshaft  23  to be relatively rotatable with respect to the internal tooth member  21 . In the speed reducer  20 , a motor  25  is fixed to the one-side member  12   a  to supply a rotational driving force to the speed reducer  20 . Namely, the rotation supplied from the motor  25  is input to the crankshaft  23  through: an input shaft  26  which is housed in the speed reducer  20 ; a small gear  26   a  which is formed in one end of the input shaft  26 ; and a large gear  27  which is fixed to one end of the crankshaft  23 , and which meshes with the small gear  26   a.    
     In the speed reducer  20 , the one-side member  12   a  of the joint portion of the robot  10 , and the internal tooth member  21  are integrated with each other to constitute one member of the speed reducer of the invention, and the member  12   b  which constitutes the other side of the joint portion of the robot  10 , and the support member  22  are integrated with each other to constitute a second member. The first member and the second member perform relative rotary motion to function as the joint portion of the robot portion. The crankshaft  23  and the external tooth members  24  are housed in a space formed by the first member and the second member. 
     The iron amount detecting devices  110  which detect the amount of iron in the lubricant in the space are attached to the one member  12   a  and other member  12   b  that constitute the joint portion of the robot  10 . 
     In the invention, the amount of iron in the lubricant  20   a  may be any kind of value as far as it indicates the amount of iron in the lubricant  20   a , such as the mass, the concentration, and the like of iron in the lubricant  20   a . The maintenance information of the speed reducers  20  means information for performing maintenance on the speed reducer  20 , such as information for inspection or replacement of the speed reducer  20 . 
     As shown in  FIG. 3 , the iron amount detecting device  110  comprises: a proximity sensor  111  which detects the amount of iron in the lubricant  20   a  (see  FIG. 2B ) in the speed reducer  20  (see  FIGS. 1 and 2A ); a wireless communicating portion  112  which wirelessly communicates with an external apparatus; a processing device  113  which is configured by a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and which controls the operations of the proximity sensor  111  and the wireless communicating portion  112 ; and a battery  114  which supplies an electric power to the proximity sensor  111 , the wireless communicating portion  112 , and the processing device  113 . Preferably, the proximity sensor  111  may be a sensor in which, even when a large number of detections are performed, the detection accuracy is hardly lowered. The battery  114  is preferably placed at a position where replacement of the battery  114  can be easily performed, such as an outer circumferential portion the speed reducer  20 . 
     As shown in  FIG. 4 , the portable wireless receiver  120  comprises: an operating portion  121  which is operated by the user; a wireless communicating portion  122  which wirelessly communicates with an external apparatus; a wired communicating portion  123  which communicates by wire with an external apparatus; a display  124  which performs various displays; a processing device  125  which is configured by a CPU, a ROM, a RAM, and the like, and which controls the operations of the wireless communicating portion  122 , the wired communicating portion  123 , and the display  124  in accordance with an operation on the operating portion  121 ; and a power supplying portion  126  which supplies an electric power to the wireless communicating portion  122 , the wired communicating portion  123 , the display  124 , and the processing device  125 . 
     As shown in  FIG. 5 , the maintenance information output apparatus  130  comprises: an operating portion  131  which is operated by the user; a wired communicating portion  132  which communicates by wire with an external apparatus; a hard disk  133  which stores data received by the wired communicating portion  132 ; a display  134  which performs various displays; a processing device  135  which is configured by a CPU, a ROM, a RAM, and the like, and which controls the operations of the wired communicating portion  132 , the hard disk  133 , and the display  134  in accordance with an operation on the operating portion  131 ; and a power supplying portion  136  which supplies an electric power to the wired communicating portion  132 , the hard disk  133 , the display  134 , and the processing device  135 . The wired communicating portion  132  receives data of the amount of iron from the portable wireless receiver  120  (see  FIG. 1 ), and constitutes a receiving portion. The display  134  outputs maintenance information of the speed reducer  20  (see  FIG. 1 ), and constitutes an outputting portion. The processing device  135  controls the display  134  to output maintenance information of the speed reducer  20  when the amount of iron obtained from the portable wireless receiver  120  is equal to or larger than a threshold value, and constitutes a controlling portion. The processing device  135  may operate in accordance with programs which are previously stored in the ROM, or alternatively operate in accordance with programs which are externally obtained through a recording medium or a network. 
     Next, the operation of the maintenance information output system  100  will be described. 
     First, the operation when the portable wireless receiver  120  obtains data of the amounts of iron in the lubricants  20   a  in the speed reducers  20  from the iron amount detecting devices  110 , and stores the data will be described. 
     When the user carries the portable wireless receiver  120  to the vicinity of the industrial robot  10  and selects one of the plural speed reducers  20  of the industrial robot  10  through the operating portion  121  of the portable wireless receiver  120 , the processing device  125  of the portable wireless receiver  120  requests through the wireless communicating portion  122 , in the case where the wireless communicating portion  112  of the iron amount detecting device  110  attached to the speed reducer  20  which is selected by the user can communicate with the wireless communicating portion  122 , the iron amount detecting device  110  attached to the speed reducer  20  which is selected by the user, to transmit data of the amount of iron in the lubricant  20   a  in the speed reducer  20 . 
     When the iron amount detecting device  110  receives the request for transmission of the data of the amount of iron in the lubricant  20   a  in the speed reducer  20  from the portable wireless receiver  120  through the wireless communicating portion  112 , the processing device  113  of the iron amount detecting device detects the amount of iron in the lubricant  20   a  in the speed reducer  20  by the proximity sensor  111 , and transmits data of the detected amount of iron to the portable wireless receiver  120  through the wireless communicating portion  112 . 
     When the portable wireless receiver  120  receives the data of the amount of iron transmitted through the wireless communicating portion  122  from the wireless communicating portion  112  of the iron amount detecting device  110 , the processing device  125  of the portable wireless receiver stores the received data of the amount of iron into the RAM, and then displays the data on the display  124 . 
     The portable wireless receiver  120  performs an operation similar to that described above on the plural speed reducers  20 , whereby, with respect to each of the plural speed reducers  20 , data of the amount of iron in the lubricant  20   a  in the speed reducer  20  can be stored. 
     Next, the operation when the maintenance information output apparatus  130  obtains data of the amounts of iron in the lubricants  20   a  in the speed reducers  20  from the portable wireless receiver  120 , and stores the data will be described. 
     When the user carries the portable wireless receiver  120  to the vicinity of the maintenance information output apparatus  130 , connects the portable wireless receiver  120  with the maintenance information output apparatus  130  through a communication cable which is not shown, and requests the maintenance information output apparatus  130  through the operating portion  131  to obtain the data of the amounts of iron stored in the RAM of the processing device  125  of the portable wireless receiver  120 , the processing device  135  of the maintenance information output apparatus  130  requests the portable wireless receiver  120  through the wired communicating portion  132  to transmit the data of the amounts of iron stored in the RAM of the processing device  125 . 
     When the portable wireless receiver  120  receives the request for transmission of the data of the amounts of iron stored in the RAM from the maintenance information output apparatus  130  through the wired communicating portion  123 , the processing device  125  of the portable wireless receiver transmits all the data of the amounts of iron stored in the RAM to the maintenance information output apparatus  130  through the wired communicating portion  123 . 
     When the maintenance information output apparatus  130  receives the data of the amounts of iron transmitted through the wired communicating portion  132  from the wired communicating portion  123  of the portable wireless receiver  120 , the processing device  135  of the maintenance information output apparatus stores the received data of the amount of iron into the hard disk  133 . 
     Next, with respect to each of the plural speed reducers  20  of the industrial robot  10 , the processing device  135  displays the latest value of the amounts of iron stored in the hard disk  133 , and a time series such as shown in  FIG. 6  on the display  134 . 
     Then, with respect to each of the plural speed reducers  20  of the industrial robot  10 , the processing device  135  performs a data analysis process shown in  FIG. 7 . 
     In the data analysis process shown in  FIG. 7 , the processing device  135  determines whether the latest value of the amounts of iron stored in the hard disk  133  is equal to or larger than a threshold value x 1  (see  FIG. 6 ) or not (S 151 ). 
     If the processing device  135  determines in S 151  that the latest value of the amounts of iron stored in the hard disk  133  is smaller than the threshold value x 1  as between times t 1  to ta shown in  FIG. 6 , the processing device ends the data analysis process. If the processing device  135  determines in S 151  that the latest value of the amounts of iron stored in the hard disk  133  is equal to or larger than the threshold value x 1  as between times tb to td shown in  FIG. 6 , the processing device determines whether the latest value of the amounts of iron stored in the hard disk  133  is equal to or larger than a threshold value x 2  (see  FIG. 6 ) or not (S 152 ). 
     If the processing device  135  determines in S 152  that the latest value of the amounts of iron stored in the hard disk  133  is smaller than the threshold value x 2  as in times tb and tc shown in  FIG. 6 , the processing device displays information for prompting the user to prepare for replacement of the speed reducer  20 , as maintenance information on the display  134  (S 153 ), and ends the data analysis process. For example, the information for prompting the user to prepare for replacement of the speed reducer  20  is information for instructing preparation of a replacement speed reducer within two months. In S 153 , in addition to display of the information for prompting the user to prepare for replacement of the speed reducer  20  on the display  134 , the processing device  135  may display also information indicating how many days later the user preferably performs a series of operations of causing the maintenance information output apparatus  130  to obtain the data of the amount of iron in the lubricant  20   a  in the speed reducer  20  from the iron amount detecting device  110  through the portable wireless receiver  120  and perform the data analysis process, as maintenance information on the display  134 . If the processing device  135  determines that the latest value of the amounts of iron stored in the hard disk  133  is equal to or larger than the threshold value x 2  as in time td shown in  FIG. 6 , the processing device displays information for prompting the user to replace the speed reducer  20 , as maintenance information on the display  134  (S 154 ), and ends the data analysis process. 
     The processing device  135  is configured so that, after the device receives through the wired communicating portion  132  the data of the amount of iron transmitted through the wired communicating portion  123  of the portable wireless receiver  120 , the device displays the latest value of the amounts of iron and a time series on the display  134 . Alternatively, the device may be configured so that, when requested by the user through the operating portion  131 , the device displays the latest value of the amounts of iron and a time series on the display  134 . 
     The processing device  135  is configured so that, after the device receives through the wired communicating portion  132  the data of the amount of iron transmitted through the wired communicating portion  123  of the portable wireless receiver  120 , the device performs the data analysis process shown in  FIG. 7 . Alternatively, the device may be configured so that, when requested by the user through the operating portion  131 , the device performs data analysis process shown in  FIG. 7 . 
     As described above, on the basis of the amount of iron which is actually produced in the lubricant  20   a  in the speed reducer  20  as a result of wear of the speed reducer  20 , the maintenance information output apparatus  130  outputs maintenance information of the speed reducer  20 . Therefore, the apparatus can output maintenance information of the speed reducer  20 , more adequately than the conventional art. 
     In the maintenance information output apparatus  130 , furthermore, threshold values of plural steps or the threshold values x 1 , x 2  are disposed, and the maintenance information is disposed in plural steps in accordance with the threshold values x 1 , x 2 . Therefore, the maintenance information output apparatus can allow the user to perform stepwise maintenance. 
     The maintenance information output system  100  is configured so as to output maintenance information in the form of display. Alternatively, maintenance information may be output by a method other than display. For example, the maintenance information output system  100  may output maintenance information in the form of sound. 
     In the maintenance information output system  100 , the two steps of threshold values or the threshold values x 1 , x 2  are disposed. Alternatively, three or more steps of threshold values may be disposed. 
     In the maintenance information output system  100 , the communication between the portable wireless receiver  120  and the maintenance information output apparatus  130  is performed by wire. Alternatively, the communication may be performed by wireless. 
     The maintenance information output system  100  comprises the portable wireless receiver  120  which obtains data of the amounts of iron from the iron amount detecting devices  110 , and the maintenance information output apparatus  130  which performs the data analysis process on the basis of the data of the amounts of iron obtained from the portable wireless receiver  120 . Alternatively, a single device may obtain data of the amounts of iron from the iron amount detecting devices  110 , and performs the data analysis process. 
     An eccentric oscillation speed reducer is used as the speed reducer  20 . The invention can be applied to any type of speed reducer as far as steel products are used in components of the speed reducer, and the structure of the speed reducer itself may not be formed as an eccentric oscillation speed reducer. However, it is advantageous to apply the invention to a speed reducer comprising plural rotation transmitting portions of an industrial robot, because maintenance information of plural reductions can be simultaneously managed. 
     In the case of an eccentric oscillation speed reducer which has a relatively complex internal structure and is hardly disassembled, particularly, it is advantageous to apply the invention and to be able to know necessity/unnecessity of maintenance. 
     In the above, the description has been made with using the example in which the iron amount detecting devices  110  are attached to both the members  12   a ,  12   b  that constitute the joint portion of the robot. The placement of the iron amount detecting device is not restricted to that in which the iron amount detecting devices are attached to both the members that constitute the joint portion. One iron amount detecting device may be disposed only on one side. Plural iron amount detecting devices may be placed on one face and at positions opposed to plural crankshafts, respectively. In the above, the example in which the iron amount detecting devices are attached to the members that constitute the joint portion of the robot has been described. In a speed reducer which is unitized in a state where components of the speed reducer itself are housed in a housing or the like and lubricating oil is hermetically enclosed, maintenance information can be obtained while an iron amount detecting device is attached to the housing. 
     INDUSTRIAL APPLICABILITY 
     The maintenance information output apparatus and maintenance information output system of the invention output maintenance information of a speed reducer on the basis of the amount of iron which is actually produced in the lubricant in the speed reducer as a result of wear of the speed reducer. Therefore, the apparatus and the system can output maintenance information of the speed reducer, more adequately than the prior art. Also in the case where the invention is applied to an eccentric oscillation speed reducer, moreover, maintenance information of the speed reducer can be obtained on the basis of the detected amount of iron.