JP3404957B2 - Press-fit control method for connector press-fitting device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press-fit control method for a connector press-fitting device. In particular, the present invention relates to a press-fit control method that does not apply excessive pressure to a printed board when a solderless press-fit type connector called a “press-fit connector” is pressed into the printed board. For example, there is a connector press-fitting device described in the specification of Japanese Patent Application No. 5-288755 by the present applicant. 2. Description of the Related Art Next, the structure of a conventional connector press-fitting device will be described with reference to FIG. 4 is a connector, 2
Is a cylinder, 3 is a printed circuit board, 4 is a pressure sensor, 5 is a servo valve, and 7 is a control unit. [0003] In FIG. 4, the upper end of the pin of the connector 1 is inserted into the press-fitting head 8, and the connector 1 is suction-held by the press-fitting head 8. Push rod 8a is provided at the upper end of press-fit head 8.
And the guide shaft 8b are attached. A compression coil spring 8d is wound between the base 9 and the head of the push rod 8a, and the compression coil spring 8d urges the force for moving the press-fit head 8 upward. [0004] The cylinder 2 is a reciprocating hydraulic cylinder. When the cylinder 2 is driven, the piston rod of the cylinder 2 pushes down the connector 1. [0005] Below the press-fit head 8, the printed circuit board 3 is provided.
Is arranged. The printed circuit board 3 is mounted on a die 10. Relief holes corresponding to through holes formed in the printed board 3 are formed in the die 10. X table 10X
Moves the die 10 in the X-axis direction on the plane. The Y table 10Y moves the X table 10X in the Y axis direction on a plane. The moving table is constituted by the X table 10X and the Y table 10Y, and the moving table is placed on the bed 10Z. The pressure sensor 4 is interposed between the tip of the piston rod of the cylinder 2 and the head of the push rod 8a, and the pressure sensor 4 detects the reaction force when the pin of the connector 1 is pressed into the through hole of the printed circuit board 3 by a voltage signal. And output. As the pressure sensor 4, a strain gauge such as a load cell is used. [0007] The servo valve 5 is connected to the cylinder 2. The servo valve 5 is a direction / flow rate control type electric / hydraulic valve, and can continuously control the flow of oil and its flow rate by a current signal. If the flow rate of the servo valve 5 is properly controlled, the pressing force of the cylinder 2 can be controlled. As the servo valve 5, for example, an SVD-11 type electric / hydraulic servo valve manufactured by Yuken Kogyo KK is used. The servo valve 5 shown in FIG. 4 is in a non-energized state.
When the first command current is applied to the servo valve 5 from the state shown in FIG. 4, the spool moves in the first direction, the A port and the P port are connected, and the B port and the R port are connected. The P port is connected to the hydraulic pump, depresses the piston rod of the cylinder 2, and the return oil of the cylinder 2 is returned from the R port to the oil tank. When the second command current is applied to the servo valve 5, the piston rod of the cylinder 2 is pulled up. The control section 7 comprises a comparing means 7A, an output voltage generating means 7B and a voltage / current converting means 7C. The comparison means 7A receives the output voltage “P” of the pressure sensor 4 and the set pressure value “Ps”. The comparison means 7A outputs the output voltage "P".
And the set pressure value “Ps”. The output voltage generating means 7B outputs "P"<"Ps".
In this case, the first voltage is generated such that the pressure of the cylinder 2 becomes "Ps". The output voltage generation means 7B outputs “P” ≧
When the pressure becomes "Ps", the pressure of the cylinder 2 becomes "Ps".
Is generated. The output voltage generating means 7B performs feedback control to maintain "Ps". The voltage / current converter 7C receives the output voltage of the output voltage generator 7B, converts the output voltage into a current value, outputs the current value to the servo valve 5, and controls the direction and the flow rate of the servo valve 5. The components of the control unit 7 shown in FIG. 4 are controlled or commanded by the CPU. For example, it is assumed that an analog value is converted into a digital value and processed inside the comparing means 7A. The pressure set value and the like are written in the memory by input means such as a keyboard. Next, the relationship between the connector 1 and the printed circuit board 3 will be described with reference to FIG. FIG. 5 is an enlarged view of a main part of FIG. The connector 1 is composed of a pin 1A and a housing 1B, and the pin 1A is held on the housing 1B by a mounting portion 12. The tip 14 of the pin 1A enters the through-hole 3A of the printed circuit board 3, and the press-fitting head 8 having a hole corresponding to the pin arrangement pushes the mounting portion 12 of the pin 1A. Make an electrical connection. In FIG. 5, the inner diameter of the through hole 3A is smaller than the outer shape of the press-fitting portion 11 and larger than the outer shape of the tip portion 14. The press-fit portion 11 is inserted into the through hole 3A.
Is press-fitted, the press-fit portion 11 is compressed and deformed and connected to the through hole 3A. Since the pins 1A and the through holes 3A are as described with reference to FIG. 5, when the connector 1 is press-fitted into the printed circuit board 3 in the apparatus of FIG. Then, a weak reaction force is detected by the pressure sensor 4. When the press-fit portion 11 starts to be inserted into the through hole 3A, a strong reaction force is detected by the pressure sensor 4. When the bottom surface of the housing 1 </ b> B is pressed against the printed circuit board 3, the pressure of the cylinder 2 is detected by the pressure sensor 4. In the connector press-fitting device shown in FIG.
Cylinder 2 so that through hole 3A is well connected to
Keeps the connector 1 pressed against the printed circuit board 3 for a certain period of time. After a certain period of time, the press-fit head 8 returns,
Press the next connector into the printed circuit board. Next, the relationship between the piston stroke of the cylinder 2 in FIG. 4, the piston speed, and the value detected by the pressure sensor 4 will be described with reference to the operation cycle diagram of FIG. Cycle line 61 in FIG.
Indicates a piston stroke of the cylinder 2, a cycle line 62 indicates a piston speed of the cylinder 2, and a cycle line 63 indicates a detected value of the pressure sensor 4. The horizontal axis in FIG. 6 is time, and a series of cycle starts when the tip of the pin 1A is inserted into the through hole 3A for convenience of explanation. During the time t1 after the piston starts lowering, the tip 14 of the pin 1A is inserted into the through hole 3A, so that the value detected by the pressure sensor 4 is theoretically zero. During the time t2 between point B and point C, the press-fit portion 11 is press-fitted into the through hole 3A. Press-fit part 11 between BC
However, the pressure value of the pressure sensor 4 increases at a substantially constant gradient. The point C in FIG. 6 is when the bottom surface of the housing 1B contacts the printed circuit board 3. Since the cylinder 2 is controlled to descend until it reaches the set pressure value PS, the pressure gradient becomes steep during the time t3 from the point C to the point D at which the piston stops descending. As described above, the time t4 during which the piston is stopped from descending and stopped is a holding time previously determined through experiments and experiences so that the press-fit portion 11 and the through hole 3A can be connected well. The holding time t4 is input to the control unit 7 in FIG. 4 in advance. After the holding time t4 elapses, the piston moves up and a series of press-fitting cycles is completed. In the apparatus shown in FIG. 4, the force for press-fitting the connector into the printed circuit board is 20 k per pin.
g is required. Pressing a 200-pin connector requires 4 tons. However, the press-fitting varies greatly depending on the variation in the inner diameter of the through hole and the variation in the outer dimensions of the press-fit portion of the pin. For example, if the inner diameter of the through hole is larger than the outer diameter of the pin, less press-in is required. In the opposite case, a large pressure input is required. In the apparatus shown in FIG. 3, a large press-fit value Ps which can be sufficiently press-fitted is set in consideration of the worst condition. For this reason, there is a problem that the connectors cannot be individually pressed into the printed circuit board with proper press-fitting, but rather an excessive force is applied to the printed circuit board. According to the present invention, a pressure gradient value, which is a change in pressure input per unit time, is calculated and compared with a known pressure gradient value. An object of the present invention is to provide a press-fitting control method of a connector press-fitting device for press-fitting a connector into a printed circuit board with proper press-fitting by not increasing the input. In order to achieve this object, the present invention relates to a connector press-fitting device for pressing down a connector 1 with a cylinder 2 and press-fitting the connector 1 with a printed circuit board 3. A pressure sensor 4 interposed between the rod tip and the connector 1 for converting a reaction force when the connector 1 is pressed into the printed circuit board 3 into a voltage signal, and connected to the cylinder 2 to switch the moving direction of the cylinder 2 by a current signal And a servo valve 5 for continuously controlling the pressing force of the cylinder 2. The dividing circuit 6A receives the voltage signal “P” of the pressure sensor 4 as an input and generates a pressure gradient value “Δ” per minute unit time “Δt”.
P ", and the comparison means 6B receives the known value" Porg "having a high pressure gradient and the pressure gradient value" ΔP "of the division circuit 6A as inputs, and compares the known value" Porg "with the pressure gradient value" ΔP ". , The output voltage generating means 6C receives the comparison value of the comparing means 6B as an input, and when “ΔP” <“Porg”, generates a first output voltage for moving the cylinder 2 at the first pressing force,
When “ΔP” ≧ “Porg”, the cylinder 2 is moved to the first position.
Generates a second output voltage that is a second pressure slightly higher than the pressure applied to the servo valve 5. The voltage-current converter 6D receives the output voltage of the output voltage generator 6C as an input, and controls the servo valve 5 with the output voltage. Output current. According to the present invention, a pressure sensor 4 for converting a reaction force when the connector 1 is pressed into the printed circuit board 3 into a voltage signal.
And a servo valve 5 capable of controlling the pressing force of the cylinder 2. The present invention utilizes the phenomenon in the above configuration that the pressure gradient value becomes steep after the connector 1 is pressed down and the bottom surface of the housing 1B comes into contact with the printed circuit board 3. That is, a pressure gradient value is constantly calculated by dividing the change detection value of the pressure sensor 4 by a minute unit time, and the above-mentioned steep gradient value is stored in the control unit as a known value. Since the cylinder 2 presses the connector with the press input “P” at the time when the connector becomes, the connector can be pressed into the printed circuit board with an appropriate press input. Next, the structure of a connector press-fitting device according to the present invention will be described with reference to the embodiment shown in FIG. Reference numeral 6 in FIG. 1 denotes a control unit, and the other components are the same as those in FIG. That is, in the present invention, the configuration excluding the control unit is the same as the conventional connector press-fitting device, and is an improved press-fitting control method. Therefore, in FIG. 1, the moving mechanism of the connector 1 and the moving mechanism of the printed circuit board 3 are the same as those in FIG. The control unit 6 shown in FIG. 1 includes a dividing circuit 6A, a comparing means 6B, an output voltage generating means 6C and a voltage / current converting means 6
D. The division circuit 6A receives the voltage signal “P” of the pressure sensor 4 as an input and outputs a pressure gradient value “ΔP” per minute unit time “Δt”. The current pressure value Pa of the pressure sensor 4 is input to the division circuit 6A, the pressure value Pb after a minute unit time “Δt” is input, and the division circuit 6A calculates “(Pb−Pa) / Δt). And outputs a pressure gradient value “ΔP”. The comparing means 6B receives the pressure gradient value “Porg”, which is a known value having a high pressure gradient, and the pressure gradient value “ΔP” of the division circuit 6A, and receives the pressure gradient value “ΔP” that changes to the known value “Porg”. To compare. The known value “Porg” is, in short, a pressure gradient value between C and D in FIG. 5, and is more practically a coefficient specific to the connector press-fitting device, and is obtained from experiments and test operations. The output voltage generating means 6C receives the comparison value of the comparing means 6B as an input, and when "ΔP"<"Porg", generates a first output voltage for moving the cylinder 2 at the first pressure. When “ΔP” ≧ “Porg”, cylinder 2
To a second pressure that is slightly higher than the first pressure.
Output voltage. The voltage / current converting means 6D receives the output voltage of the output voltage generating means 6C, converts the output voltage into a current value, outputs the current value to the servo valve 5, and controls the direction and flow rate of the servo valve 5. The components of the control section 6 shown in FIG. 1 are controlled or commanded by the CPU. For example, it is assumed that an analog value is converted into a digital value and processed inside the comparing means 6B. Further, the pressure gradient value “Porg” and the like are written in a memory in advance by input means such as a keyboard. Next, a press-fit control procedure of the connector press-fitting device of FIG. 1 will be described with reference to a flowchart of FIG. In step 101 in FIG. 1, the CPU instructs the servo valve 5 to start press-fitting so that the cylinder 2 presses the connector 1. In step 102, the division circuit 6A reads the current pressure value "Pa" of the pressure sensor 4. In step 103, the process waits for a short time “Δt”. In step 104, the dividing circuit 6A
Is the pressure value “Pb” of the pressure sensor 4 after the minute time “Δt”
Read. In step 105, the division circuit 6A calculates the pressure gradient value “ΔP” by the operation formula “(Pb−Pa) / Δt). In step 106, the comparing means 6B compares the pressure gradient value “ΔP” with the known pressure gradient value “Porg”. If it is determined in step 106 that the pressure gradient value “ΔP” is smaller than the existing pressure gradient value “Porg”, the process returns to the previous stage of step 102. Step 106 to step 102
When the process returns to the previous stage, the previous press-fit value "Pb" is replaced with the next "Pa" and read. At step 106, when the pressure gradient value "ΔP" becomes equal to or greater than the known pressure gradient value "Porg", the output voltage generating means 6C outputs the pressure value "P" of the pressure sensor 4 to the cylinder 2
Then, an output voltage is generated so as to provide the pressing force, the pressing force is maintained, and a series of press-in control is terminated. Next, the relationship between the piston stroke of the cylinder 2 in FIG. 1, the piston speed, and the value detected by the pressure sensor 4 will be described with reference to the operation cycle diagram of FIG. The cycle line 31 of FIG.
Indicates a piston stroke of the cylinder 2, a cycle line 32 indicates a piston speed of the cylinder 2, and a cycle line 33 indicates a detected value of the pressure sensor 4. The horizontal axis in FIG. 3 is time, and a series of cycle starts when the tip of the pin 1A is inserted into the through hole 3A, similarly to FIG. 6, for convenience of explanation. During the time t1 after the piston starts to descend, the tip 14 of the pin 1A is inserted into the through hole 3A, so that the detection value of the pressure sensor 4 is theoretically zero. During the time t2 between point B and point C, the press-fit portion 11 is press-fitted into the through hole 3A. Press-fit part 11 between BC
The press-fit value increases at a substantially constant gradient, although it may vary depending on the shape of the press-fit. The point C in FIG. 3 is when the bottom surface of the housing 1B contacts the printed circuit board 3. The point C in FIG.
At the time when "P" ≥ "Porg", and after the elapse of the minute time t3, the servo valve 5 is controlled at the point D, and the detection value of the pressure sensor 4 at the point D is held as the pressure of the cylinder 2. Thereafter, after the elapse of the same holding time t4 as in FIG. 6 in which the press-fit portion 11 and the through hole 3A are well connected, the piston is raised, and a series of press-fit cycles is completed. Note that the holding time t4 is input to the control unit 6 in FIG. 1 in advance.
Further, the cycle line drawn by the dashed line in FIG. 3 shows the cycle diagram of FIG. As shown in the cycle diagram of FIG. 3, according to the present invention, a series of cycle times can be shortened, and it can be seen that unnecessary pressure is not applied to the printed circuit board. According to the present invention, a pressure sensor for converting a reaction force when a connector is pressed into a printed circuit board into a voltage signal, and a servo valve for controlling a pressing force of a cylinder for pressing the connector are provided in advance. I have. A pressure gradient value is constantly calculated by dividing the detected value of the pressure sensor change by a minute unit time, and the steep gradient value is stored in the control unit as a known value, and the pressure at the time when the detected pressure gradient value becomes a known value is obtained. Since the cylinder presses the connector with the input, the connector can be pressed into the printed circuit board with an appropriate pressure input.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a connector press-fitting device according to an embodiment of the present invention. FIG. 2 is a flowchart showing a press-fit control procedure of FIG. FIG. 3 is an operation cycle diagram of FIG. 1; FIG. 4 is a configuration diagram of a conventional connector press-fitting device. FIG. 5 is an enlarged view of a main part of FIG. 4; FIG. 6 is an operation cycle diagram of FIG. 4; [Description of Signs] 1 Connector 2 Cylinder 3 Printed circuit board 4 Pressure sensor 5 Servo valve 6A Division circuit 6B Comparison means 6C Output voltage generation means 6D Voltage-current conversion means

Claims (1)

(57) [Claims] [Claim 1] Press the connector (1) with the cylinder (2),
A connector press-fitting device for press-fitting a printed circuit board (3), which is interposed between the tip of a piston rod of a cylinder (2) and a connector (1), and is used to press-fit the connector (1) into a printed circuit board (3). A pressure sensor (4) that converts the pressure into a voltage signal and a cylinder (2) are connected to a servo valve that switches the direction of movement of the cylinder (2) and continuously controls the pressing force of the cylinder (2) using a current signal. The divider circuit (6A) receives the voltage signal “P” of the pressure sensor (4) as an input and generates a pressure gradient value “Δ” per minute unit time “Δt”.
The comparison means (6B) receives the known value “Porg” having a high pressure gradient and the pressure gradient value “ΔP” of the division circuit (6A) as inputs, and outputs the known value “Porg” and the pressure gradient value “ΔP”. The output voltage generation means (6C) receives the comparison value of the comparison means (6B) as an input, and when "ΔP"<"Porg", the output voltage generating means (6C) moves the cylinder (2) with the first pressing force. 1 to generate an output voltage of “Δ
When "P" ≥ "Porg", the cylinder (2) generates a second output voltage which is a second pressure slightly higher than the first pressure, and the voltage-current conversion means (6D) outputs A press-fitting control method for a connector press-fitting device, comprising: receiving an output voltage of a voltage generating means (6C) as input, and converting the output voltage into an output current for controlling a servo valve (5).