JP4707576B2 - Component mounting device - Google Patents

Description

  The present invention relates to a component mounting apparatus for mounting an electronic component on a circuit board, and in particular, a component for mounting a component on a circuit board by transmitting a driving force of a motor through a power transmission mechanism such as a belt to move a mounting head. It relates to the on-board device.

  In the component mounting apparatus, a configuration having a head moving mechanism that transmits a driving force of a motor via a belt to move a mounting head is widely adopted. In such a component mounting apparatus, due to expansion and contraction of the belt, a difference occurs between the rotation amount of the drive motor and the movement amount of the mounting head, and the mounting head is displaced.

  A technique for correcting this misalignment is described in Patent Document 1 below. According to this, the rotation amount of the drive pulley and the driven pulley with the belt stretched between each other is detected, the difference in rotation amount between both pulleys is measured, and the displacement of the mounting head is corrected according to the difference. is doing. Here, by detecting the rotation amount of the drive pulley, the rotation amount of the drive motor that rotationally drives the drive pulley is indirectly detected. Further, by detecting the rotation amount of the driven pulley, the movement amount of the mounting head corresponding to the travel amount of the belt corresponding to the rotation amount is indirectly detected. Therefore, based on the detected difference between the rotation amounts of both pulleys, it is possible to correct the displacement of the mounting head due to the difference between the rotation amount of the drive motor and the movement amount of the mounting head due to the expansion and contraction of the belt.

On the other hand, if the belt becomes too loose for some reason, there is a possibility that an abnormality of the component mounting apparatus may occur due to hunting of the control system. On the other hand, using the technique of Patent Document 1, the amount of rotation of the drive motor and the amount of movement of the mounting head are detected and the difference is measured. If the difference is large, it is detected as an abnormality due to the looseness of the belt. Conceivable.
Japanese Patent Publication No. 7-70875

  However, in an actual component mounting apparatus, a failure may occur in detection means such as a rotary encoder that detects the amount of rotation of the drive motor and a linear encoder that detects the amount of movement of the mounting head. Due to the failure, the difference in detected value between the rotation amount of the drive motor and the movement amount of the mounting head may increase. In other words, even if an abnormality in the device related to the movement of the mounting head is detected based on the difference between the detected values of the rotation amount of the drive motor and the movement amount of the mounting head, whether the abnormality is due to the looseness of the belt or the encoder is faulty. The cause or cause cannot be identified. For this reason, even if an abnormality is detected and the apparatus is stopped, it takes time to identify the cause of the abnormality from a plurality of possible factors, and it takes time to recover the apparatus.

  Therefore, an object of the present invention is to reliably detect the cause of an abnormality in the above-described type of component mounting apparatus.

In order to solve the above problems, the present invention (Claim 1)
In a component mounting device that mounts a component by moving a moving body for component mounting with a drive motor,
A rotation amount detecting means for detecting the rotation amount of the drive motor;
A moving amount detecting means for detecting a moving amount of the moving body due to rotation of the drive motor;
A deviation between the rotation amount of the drive motor and the movement amount of the moving body, and a calculation means for calculating a time differential value of the deviation,
A component mounting device that detects an abnormality in the component mounting device based on the deviation and its time differential value ,
When the deviation exceeds a predetermined deviation threshold value and the time differential value does not exceed the predetermined time differential threshold value, there is an abnormality in the power transmission mechanism that transmits the driving force of the drive motor to the moving body. It is characterized by judging .

The present invention (Claim 2)
In a component mounting device that mounts a component by moving a moving body for component mounting with a drive motor,
A rotation amount detecting means for detecting the rotation amount of the drive motor;
A moving amount detecting means for detecting a moving amount of the moving body due to rotation of the drive motor;
A deviation between the rotation amount of the drive motor and the movement amount of the moving body, and a calculation means for calculating a time differential value of the deviation,
A component mounting device for detecting an abnormality in the component mounting device based on the deviation and its time differential value,
If the deviation exceeds a predetermined deviation threshold value and the time differential value exceeds a predetermined time differential threshold value, it is determined that there is an abnormality in the rotation amount detection means and / or the movement amount detection means. It is characterized by doing .

According to the present invention (Claim 1) , an abnormality is detected based on the deviation between the rotation amount of the drive motor and the movement amount of a moving body such as a mounting head moved by the drive motor, and the time differential value of the deviation. When the deviation exceeds a predetermined deviation threshold value and the time differential value does not exceed the predetermined time differential threshold value, the power transmission mechanism that transmits the driving force of the drive motor to the moving body is provided. Since it is determined that there is an abnormality, it is possible to reliably detect where the abnormality is.
According to the present invention (Claim 2), the abnormality is determined based on the deviation between the rotation amount of the drive motor and the movement amount of the moving body such as the mounting head moved by the drive motor, and the time differential value of the deviation. If the deviation exceeds a predetermined deviation threshold value and the time differential value exceeds a predetermined time differential threshold value, the rotation amount detection means and / or the movement amount detection means Since it is determined that there is an abnormality, it is possible to reliably detect where the abnormality is.

  Hereinafter, embodiments of the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  FIG. 1 schematically shows the configuration of a component mounting apparatus according to this embodiment. Reference numeral 18 denotes a mounting head as a moving body having a suction nozzle 16 that sucks the electronic component 10 and is moved in the X-axis direction and the Y-axis direction orthogonal to each other in a horizontal plane by driving of an XY robot 22 that is a head moving mechanism. The Although not shown in detail, the mounting head 18 has a Z-axis moving mechanism that moves the suction nozzle 16 in the Z-axis direction (vertical direction), and rotates the suction nozzle 16 about the θ-axis (nozzle axis). A θ-axis rotation mechanism is provided.

  When mounting a component, first, the mounting head 18 is moved to a desired position on the component supply unit 12 by driving the XY robot 22, and then the suction nozzle 16 is lowered to suck the desired electronic component 10. After the nozzle 16 is raised, the mounting head 18 is moved onto the component recognition camera 24, the sucked component 10 is imaged, and the suction posture of the component is recognized. Thereafter, the suction posture is corrected, and the component is mounted at a desired position on the circuit board 14 that has been transported by the board transport device 20. Thereafter, the mounting head 18 is moved again onto the component supply unit 12, and the components 10 are sequentially mounted on the substrate 14 by repeating the above-described operation.

  FIG. 2 shows details of the configuration of the XY robot 22. The mounting head 18 is attached to the X-axis guide 28 so as to be slidable in the X-axis direction. An X-axis motor 32 is provided at one end of the X-axis guide 28 in the X-axis direction, and a driving pulley (not shown) is coupled to the rotation shaft. A driven pulley (not shown) is rotatably provided at the other end of the X-axis guide 28. The belt 34 is wound around the drive pulley and the driven pulley and stretched, and the mounting head 18 is attached to a predetermined portion of the belt 34. The belt 34 travels along the X-axis direction by the rotational drive of the X-axis motor 32, and the mounting head 18 moves in the X-axis direction accordingly.

  A wheel (not shown) in which a large number of slits are formed in the circumferential direction at minute intervals is attached to the rotation shaft of the X-axis motor 32, and a pulse signal is detected by detecting the slits in the wheel on the main body of the X-axis motor. A sensor (not shown) for outputting is provided. The wheel and sensor constitute a motor encoder (rotary encoder: 33 in FIG. 3) as means for detecting the amount of rotation of the X-axis motor 32, and a pulse signal having the number of pulses corresponding to the amount of rotation of the X-axis motor 32 is obtained. Output.

  Further, a linear scale 29 in which a large number of slits are formed at predetermined minute intervals is attached to the X-axis guide 28 along the X-axis direction. A sensor (not shown) that detects a slit of the scale 29 and outputs a pulse signal is provided in the mounting head 18. The linear scale 29 and sensor constitute an X-axis linear encoder (44 in FIG. 3) as means for detecting the amount or position of movement of the mounting head 18 in the X-axis direction. A pulse signal with the number of pulses corresponding to the amount of movement or position is output.

  Further, both ends of the X-axis guide 28 in the X-axis direction are attached to be slidable in the Y-axis direction along the first and second Y-axis guides 30A and 30B. First and second Y-axis motors 36A and 36B are provided in the vicinity of one end of each of the Y-axis guides 30A and 30B in the Y-axis direction, and drive pulleys 39A and 39B are provided on the respective rotation shafts. Is fixed. Drive pulleys 40A and 40B are provided in the vicinity of the other ends of the Y-axis guides 30A and 30B. The belt 38A is wound and stretched around the pulleys 39A and 40A, and the belt 38B is wound and stretched around the pulleys 39B and 40B. The predetermined portions of the belts 38A and 38B are fixed to both ends of the X-axis guide 28 in the X-axis direction. The belts 38A and 38B travel along the Y-axis direction by the rotational drive of the Y-axis motors 36A and 36B, and accordingly, the X-axis guide 28 moves in the Y-axis direction, and the mounting head 18 moves in the Y-axis direction.

  Each of the Y-axis motors 36A and 36B is provided with a motor encoder (not shown) (37A and 37B in FIG. 3) which is a rotation amount detecting means similar to that provided for the X-axis motor 32. The pulse signals having the number of pulses corresponding to the respective rotation amounts of the Y-axis motors 36A and 36B are output.

  Further, a linear scale 31 similar to the linear scale 29 is attached to the first Y-axis guide 30A along the Y-axis direction. A sensor (not shown) that detects the slit of the scale 31 and outputs a pulse signal is provided at the left end of the X-axis guide 28 in FIG. The scale 31 and the sensor constitute a Y-axis linear encoder (45 in FIG. 3) as means for detecting the amount or position of movement of the mounting head 18 in the Y-axis direction, and the X-axis guide 28 moves in the Y-axis direction. A pulse signal having the number of pulses corresponding to the movement amount or position, that is, the movement amount or position of the mounting head 18 in the Y-axis direction is output.

  FIG. 3 shows the configuration of a control system related to the drive control of the XY robot 22 and the detection of an abnormality related to the movement of the mounting head 18. In addition, illustration of drive systems other than the XY robot 22, for example, drive systems such as the Z-axis movement mechanism and the θ-axis rotation mechanism of the suction nozzle 16, is omitted.

  In FIG. 3, reference numeral 41 denotes a controller for controlling the entire component mounting apparatus, which is composed of a microcomputer including a CPU, a ROM, a RAM, and the like. To control the whole. When the mounting head is moved to the target position in the X-axis direction or the Y-axis direction, the X-axis motor 32 and the first and second Y-axis motors 36A and 36B correspond to the target position via a motor driver (not shown). It is rotated by the specified amount. The rotation amounts of the motors 32 and 36A and 36B are detected by the motor encoders 33 and 37A and 38B and input to the controller 41. The movement amount or position of the mounting head 18 in the X-axis direction and Y-axis direction by driving each motor 32 and 36A, 36B is detected by the X-axis and Y-axis linear encoders 44, 45 and input to the controller 41. Is done.

  The controller 41 displays various information such as the state of the apparatus on the display unit 43 including a liquid crystal display. When the above abnormality is detected, a warning for notifying the user of the detected abnormality is displayed.

  In such a configuration, when the mounting head 18 is moved by the X-axis motor 32, the rotation amount of the X-axis motor 32 detected by the motor encoder 33 and the mounting head 18 detected by the X-axis linear encoder 44 are detected. The amount of movement in the X-axis direction is compared, and abnormality detection is performed. Here, since the resolutions of the encoders 33 and 44 are usually different, they cannot be compared as they are. For this reason, the ratio Mp / Rx obtained by dividing the output value Mp of the motor rotation amount of the motor encoder 33 by Rx, where Rx is the ratio of both resolutions when the output value of the head movement amount of the linear encoder 44 is used as a reference. The output value Lp of the encoder 44 is compared. Here, if there is no expansion / contraction of the belt 34, the values of Mp / Rx and Lp are equal. However, since the belt 34 is expanded and contracted during actual movement, the movement of the mounting head 18 is delayed or advanced in accordance with the expansion and contraction, thereby causing a difference between the value of Mp / Rx and the value of Lp. For this reason, for example, when the mounting head 18 is moved, the deviation amount D (= (Mp / Rx) −Lp) obtained by subtracting the Lp value from the Mp / Rx value is a graph with respect to the change in the head moving speed Vh. As shown in FIG.

  The maximum value Dmax of the deviation amount D at this time becomes small when the tension of the belt 34 is high, and shows a large value when the belt 34 is loosened. Therefore, in order to detect the looseness of the belt 34, an appropriate predetermined deviation threshold value Ds is set for the deviation amount D, and the maximum value Dmax of the deviation amount D exceeds the deviation threshold value Ds. A method of determining that the belt 34 is loose can be considered.

  However, even if the belt 34 is not loose, for example, a signal system in which the output of the encoder is lost for a certain period of time due to, for example, a failure of the motor encoder 33 and / or the linear encoder 44 or a poor contact of a connector to which the belt is connected. In the case of the above problem, the deviation amount D shows a large value for a certain time as shown in FIG. In such a case, when the maximum deviation amount Dmax exceeds the deviation threshold value Ds, it is indistinguishable from the case where the belt 34 is loosened.

  On the other hand, when the change amount (time differential value) dD / dt with respect to the unit time of the deviation amount D in each of FIGS. 4 and 6 is calculated, the case of FIG. 4 is as shown in FIG. 5, and the case of FIG. As shown in FIG. That is, when the signal system such as the motor encoder 33 and / or the linear encoder 44 is abnormal, there is a rapid change in the deviation amount D as shown in FIG. 6, and therefore the deviation change amount dD / dt as shown in FIG. The maximum value dDmax takes a significantly high value. On the other hand, when the belt 34 is loose, there is no sudden change in the deviation amount D as shown in FIG. 4, so the deviation change amount dD / dt falls within a relatively small value as shown in FIG. dDmax is not so large.

  For this reason, when the maximum value Dmax of the deviation amount D exceeds the predetermined deviation threshold value Ds, if the maximum value dDmax of the deviation change amount dD / dt is less than or equal to the predetermined time differential threshold value dDs, the belt If the time differential threshold value dDs is exceeded, it is determined that the abnormality is caused by the looseness of the belt 34. For example, a failure other than the looseness of the belt 34, for example, the failure of the motor encoder 33 and / or the linear encoder 44, or the pulley around which the belt 34 is wound It can be determined that there is an abnormality due to damage to the product.

  In order to detect an abnormality as described above, in this embodiment, a circuit configuration as shown in FIG. 8 is provided. Each circuit can be realized by the CPU of the controller 41, or can be realized individually as hardware.

  In FIG. 8, the output value Mp of the motor encoder 33 corresponding to the rotation amount of the X-axis motor 32 is input to the division circuit 81 and divided by the resolution ratio Rx of the motor encoder 33 and the linear encoder 44. The value of the division result Mp / Rx and the output value Lp of the linear encoder 44 corresponding to the amount of movement of the mounting head 18 in the X-axis direction are input to the subtractor 82, and the deviation is obtained by subtraction of (Mp / Rx) -Lp. The quantity D is determined. The deviation amount D is input to the max hold circuit 85. The max hold circuit 85 holds and outputs the maximum value Dmax of the changing deviation amount D. Further, the deviation amount D is also input to the differentiation circuit 83. The differentiating circuit 83 calculates a time differential value dD / dt of the deviation amount D, and the maximum value dDmax is held by the max hold circuit 84 and output.

  Based on the deviation thus calculated and its time differential value, the CPU of the controller 41 identifies an abnormality in the component mounting apparatus according to the flowchart of FIG.

  First, in step S1, the X-axis motor 32 is driven to move the mounting head 18 along the X-axis, and in step S2, the maximum deviation value Dmax between the rotation amount of the X-axis motor and the movement amount of the mounting head, The maximum value dDmax of the time differential value is acquired.

  Next, in step S3, it is determined whether or not the acquired deviation amount maximum value Dmax exceeds a predetermined deviation threshold value Ds. If it does not exceed, it is determined that there is no abnormality and the abnormality detection process is terminated. If it exceeds, the process proceeds to step S4.

  In step S4, it is determined whether or not the maximum value dDmax of the obtained time differential value of the deviation exceeds a predetermined time differential threshold value dDs. If not, the process proceeds to step S5, and if it exceeds, the process proceeds to step S6.

  In step S5, it is determined that there is an abnormality due to the looseness of the belt 34 of the power transmission mechanism, the drive of the X-axis motor 32 is prohibited, and a display for warning the user of the abnormality due to the looseness of the belt 34 is displayed on the display unit 43 Thereafter, the abnormality detection process is terminated.

  In step S6, it is determined that the abnormality is caused by a cause other than the looseness of the belt, for example, an abnormality such as an output of the motor encoder 33 and / or the linear encoder 44, and the driving of the X-axis motor 32 is prohibited and the determined abnormality is determined. The display unit 43 is displayed to warn the user, and then the abnormality detection process is terminated.

  While the movement of the mounting head in the X-axis direction and the accompanying abnormality detection have been described above, the movement of the mounting head in the Y-axis direction and the accompanying abnormality detection can be performed in the same manner. In this case, a motor encoder 37A (or 37B) is used instead of the motor encoder 33, and a Y-axis linear encoder 45 is used instead of the X-axis linear encoder 44. The deviation between the rotation amount of the Y-axis motor and the movement amount of the mounting head 18 (X-axis guide 28) exceeds a predetermined deviation threshold value, and the time differential value of the deviation is a predetermined time differential threshold value. Is not exceeded, it is determined that there is an abnormality in the belt 38A (38B), the deviation exceeds a predetermined deviation threshold value, and the time differential value exceeds a predetermined time differential threshold value. If it is determined that there is an abnormality due to a cause other than the looseness of the belt, for example, the motor encoder 37A (or 37B) and / or the Y-axis linear encoder 45 is determined to be abnormal.

  As described above, according to this embodiment, when an abnormality is detected in the component mounting apparatus, there is an abnormality in the power transmission mechanism such as a belt that transmits the driving force of the drive motor to the mounting head (moving body), or It is possible to reliably determine whether there is an abnormality in the rotation amount detection means for detecting the rotation amount of the drive motor and / or the movement amount detection means for detecting the movement amount of the moving body. Therefore, the cause of the abnormality can be identified more easily in a short time, and the apparatus can be restored in a short time.

It is a perspective view which shows the structure of the component mounting apparatus of the Example of this invention. It is a top view which shows the detail of a structure of the XY robot of the apparatus. It is a block diagram which shows the structure of the control system in connection with the drive control of the XY robot of the same apparatus, and the detection of abnormality regarding a movement of a mounting head. It is a diagram which shows the time-dependent change of the deviation of the movement amount of the mounting head with respect to the rotation amount of the motor in the same apparatus. FIG. 5 is a diagram illustrating a change over time in a deviation change amount obtained by time-differentiating the deviation of FIG. 4. It is a diagram which shows the time-dependent change of the said deviation when an encoder fails. FIG. 7 is a diagram showing a change with time of a deviation change amount obtained by time-differentiating the deviation of FIG. 6. It is a block diagram which shows the circuit structure which calculates a deviation and its time differential value. It is a flowchart figure which shows the control procedure of an abnormality detection process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electronic component 12 Component supply part 14 Circuit board 16 Adsorption nozzle 18 Mounting head 20 Substrate conveyance apparatus 22 XY robot 24 Component recognition camera 28 X-axis guide 30A, 30B Y-axis guide 32 X-axis motor 33, 37A, 37B Motor encoder 34, 38A, 38B Belt 36A, 36B Y-axis motor 44 X-axis linear encoder 45 Y-axis linear encoder 81 Divider 82 Subtractor 83 Differentiation circuit 84, 85 Max hold circuit

Claims (2)

In a component mounting device that mounts a component by moving a moving body for component mounting with a drive motor,
A rotation amount detecting means for detecting the rotation amount of the drive motor;
A moving amount detecting means for detecting a moving amount of the moving body due to rotation of the drive motor;
A deviation between the rotation amount of the drive motor and the movement amount of the moving body, and a calculation means for calculating a time differential value of the deviation,
A to that part article installation device detects an abnormality in the component mounting apparatus based on said deviation and its time differential value,
If the deviation exceeds a predetermined deviation threshold value and the time differential value does not exceed the predetermined time differential threshold value, there is an abnormality in the power transmission mechanism that transmits the driving force of the drive motor to the moving body. A component mounting device characterized by being judged . In a component mounting device that mounts a component by moving a moving body for component mounting with a drive motor,
A rotation amount detecting means for detecting the rotation amount of the drive motor;
A moving amount detecting means for detecting a moving amount of the moving body due to rotation of the drive motor;
A deviation between the rotation amount of the drive motor and the movement amount of the moving body, and a calculation means for calculating a time differential value of the deviation,
A component mounting device for detecting an abnormality in the component mounting device based on the deviation and its time differential value,
Determining that the difference is beyond the predetermined deviation threshold, if and time differential value that exceeds a predetermined time differential threshold, there is an abnormality in the rotation amount detection means and / or the movement amount detecting means part article installation device characterized by.

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