JP4362244B2 - Semiconductor stack and pressure control device for the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, a laminated body in which a plurality of cooling fins each having a cooling medium channel formed therein and a flat semiconductor element are alternately laminated is sandwiched by fixing members from both sides in the laminating direction, and the fixing is performed. The present invention relates to a semiconductor stack that integrally fixes members with a plurality of fastening bolts and a pressure management device for the semiconductor stack.
[0002]
[Prior art]
For example, in a semiconductor stack used for a welding transformer or the like, a laminated body in which flat semiconductor elements are arranged between a plurality of cooling fins is configured to be pressed and clamped from both sides in the stacking direction via clampers. Yes.
[0003]
In this type of semiconductor stack, a load cell, for example, a load cell is usually sandwiched between the clamper and the laminated body, and while tightening the tightening bolts constituting the clamper while monitoring the output data of the load cell, Work to adjust the amount of load (pressing force) acting on the laminate is being performed.
[0004]
However, in this type of technology, although the load acting on the laminate can be directly grasped, the load amount can be adjusted with high accuracy, but since the load cell is incorporated, the dimension in the stacking direction becomes longer and the semiconductor There was a problem that the stack was quite expensive.
[0005]
Therefore, various proposals have been made in order to easily adjust the load without using a load cell such as a load cell. For example, a flat rectifier disclosed in Japanese Patent Laid-Open No. 50-112736 is disclosed. Is known. In this prior art, flat rectifying elements and liquid-cooled cooling fins are alternately stacked, a spring guide pressed by a spring through an insulator at one end thereof, and a visual line instruction that indicates the amount of movement of the spring guide The other end is provided with a steel ball and a push bolt for the steel ball via an insulator and a steel ball receiving bracket.
[0006]
[Problems to be solved by the invention]
By the way, in said prior art, the load amount which acts on the said laminated body is tightened, tightening a fastening bolt, monitoring the visual line indicator which instruct | indicates the displacement amount of the laminated body with respect to a clamper. However, since the amount of displacement with respect to the load amount is very small, adjustment errors and variations in the load amount become large, and a problem has been pointed out that highly accurate load amount adjustment work cannot be performed.
[0007]
The present invention solves this type of problem, and provides a semiconductor stack capable of accurately adjusting the pressure applied to the laminated body with a simple and inexpensive configuration, and a pressure management apparatus for the semiconductor stack. Objective.
[0008]
[Means for Solving the Problems]
In the semiconductor stack according to the present invention, a circumferential body centered on the central axis is formed on the surface of a disc spring that pressurizes a laminated body in which a plurality of cooling fins and flat semiconductor elements are alternately laminated in the laminating direction. For example, at least three strain detectors are arranged corresponding to positions in the same phase as the fastening bolts, spaced apart from each other at equal intervals. Since the strain data detected by the strain detector is set as a linear function of the applied pressure acting on the laminate, the applied pressure acting on the laminate can be easily obtained from the strain data.
[0009]
As a result, by performing the tightening operation of the tightening bolt while monitoring the strain data detected by the strain detector, it is possible to adjust the applied pressure acting on the laminated body with high accuracy and speed.
[0010]
Further, in the pressure management device for a semiconductor stack according to the present invention, when the tightening bolt is tightened while monitoring the strain data detected by the strain detector, each strain data detected by the strain detector is stored. It is determined whether or not it is within a predetermined range. Therefore, it is possible to easily and reliably perform the adjustment operation of the applied pressure acting on the laminated body.
[0011]
Furthermore, a temperature detector that detects the atmospheric temperature of the strain detector, a correction unit that corrects strain data based on the temperature data detected by the temperature detector, and obtains corrected strain data; and the corrected strain data is predetermined. A correction distortion data determination unit for determining whether or not it is within the range. For this reason, it is not influenced by a temperature change, and the applied pressure which acts on a laminated body can be adjusted accurately.
[0012]
Therefore, a warning signal output unit is provided that outputs a warning signal when it is determined that the distortion data or the corrected distortion data has deviated from a predetermined range. This makes it easy to detect these malfunctions even when the tightening bolts are slack due to external impacts, etc., or when cooling abnormalities occur due to the thermal expansion of the semiconductor elements during the operation of the semiconductor stack. Is possible. Since a warning signal is output at the time of abnormality, the warning signal can be fed back to the control unit that controls the semiconductor stack, or an abnormality warning can be displayed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic configuration explanatory view of a resistance welder 12 to which a semiconductor stack 10 according to a first embodiment of the present invention is assembled, and FIG. 2 is a front view of an essential part of the semiconductor stack 10.
[0014]
The resistance welder 12 includes an AC power source 14, and a welding transformer 20 is connected to the AC power source 14 via a converter 16 and an inverter 18. The semiconductor stack 10 is mounted on the welding transformer 20, and gun arms 22 a and 22 b constituting a welding gun 22 are connected to the welding transformer 20 and the semiconductor stack 10.
[0015]
The welding transformer 20 includes a cut core 24 made of a laminated steel plate, and a primary coil 26 and a secondary coil 28 combined with the cut core 24. The semiconductor stack 10 is connected to the secondary coil 28.
[0016]
As shown in FIGS. 2 and 3, the semiconductor stack 10 is disposed on the cooling fins 32 and 34 connected to the negative side end portions 28 a and 28 b of the secondary coil 28, and on both side surfaces of the cooling fins 32 and 34. Cooling fins 38, 40, 42 and 44 for sandwiching and fixing a flat semiconductor element 36, and a positive electrode plate 46 integrally connected to the side surfaces of the cooling fins 38, 40, 42 and 44.
[0017]
The cooling fins 32, 34, 38, 40, 42 and 44 are made of a copper material, and each surface is nickel-plated to prevent the occurrence of corrosion or the like. Between the cooling fins 38, 32 and 40 and between the cooling fins 42, 34 and 44, the semiconductor element 36 is disposed via an insulating member 48, respectively. First and second support plates (fixing members) 52 and 54 are arranged on both sides of the stack 50 in the stacking direction (arrow A direction), and a plurality of spaces are provided between the first and second support plates 52 and 54. For example, it is integrally fixed by four fastening bolts 56.
[0018]
The cooling fins 38, 32, 40, 42, 34, and 44 have a cooling medium (for example, cooling water) flow path 58 formed therein, and the flow path 58 has an outlet and an inlet in the stacking direction. It is provided opposite to. In the cooling fins 38 and 44, a cooling medium supply port 60a and a cooling medium discharge port 60b are formed on the side surfaces 38a and 44a, respectively. Holes 62 for inserting the fastening bolts 56 are formed at the four corners of the cooling fins 38, 32, 40, 42, 34 and 44.
[0019]
The insulating member 48 has a plate shape made of a resin-based material, and an opening 64 having the same shape as the outer shape of the semiconductor element 36 is formed at the center thereof. At the four corners of the insulating member 48, holes 66 for inserting the fastening bolts 56 are formed outside the openings 64, and connection passages 68 for communicating the inlets and outlets of the respective flow paths 58. Are formed to correspond to predetermined positions.
[0020]
The first and second support plates 52 and 54 are made of stainless steel (JIS standard SUS), and holes 69 for inserting the fastening bolts 56 are formed at the four corners of the first support plate 52. . A recess 70 is formed in the second support plate 54, a disc spring 72 is disposed in the recess 70, and screws with which the tips of the fastening bolts 56 are screwed into the four corners of the second support plate 54. A hole 74 is formed.
[0021]
As shown in FIG. 4, the disc spring 72 is coaxially disposed on the central axis O of the laminated body 50, and the surface of the disc spring 72 has a virtual circumference centered on the central axis O. At least three strain gauges (strain detectors) 78 in this embodiment are affixed on the 76 at regular intervals (for example, corresponding to the same phase position as the fastening bolt 56). Each strain gauge 78 is disposed at a position spaced apart from the central axis O by equal intervals on a line connecting the central axis O and the axis of each fastening bolt 56.
[0022]
As shown in FIGS. 2 and 3, insulating plates 80 a and 80 b are disposed on both sides of the cooling fins 38 and 44 in the stacking direction, and an insulating plate 80 c is interposed between the cooling fins 40 and 42.
[0023]
As shown in FIG. 1, the resistance welding machine 12 incorporates a pressure management device 90 according to the first embodiment. The pressure management apparatus 90 includes a strain gauge 78 and a control unit 92.
[0024]
The control unit 92 drives and controls the resistance welding machine 12, and determines whether each strain data detected by the strain gauge 78 is within a predetermined range, and the strain data is determined by the strain data. A warning signal output unit 100 that outputs a warning signal when it is determined that the vehicle has deviated from a predetermined range, and a storage unit 102 that stores welding conditions, various map data, arithmetic expressions, and the like in advance are provided.
[0025]
The operation of the semiconductor stack 10 configured as described above will be described below.
[0026]
First, the relationship between the average strain of the disc spring 72 detected by the four strain gauges 78 assembled to the semiconductor stack 10 and the load amount (pressure contact force) in the stacking direction (arrow A direction) of the semiconductor stack 10 is described. Set.
[0027]
That is, as shown in FIG. 5, the load cell 110 is arranged on the first support plate 52 constituting the semiconductor stack 10, and a pressure is applied to the load cell 110 in the direction of arrow A <b> 1 (tightening direction). As a result, the disc spring 72 is deformed, and the four strain gauges 78 provided on the disc spring 72 detect the strain of the disc spring 72. The relationship between the average strain obtained by averaging the strains detected by all strain gauges 78 and the pressure contact force (kN) measured by the load cell 110 is shown in FIG.
[0028]
In addition, said experiment is performed using the ten semiconductor stacks 10, The average value is shown by FIG. Accordingly, the strain δ (μS) and the pressure contact force P (kN) are set as linear functions. The relationship between the strain δ (μS) and the pressure contact force P (kN) shown in FIG. 6 or the target strain data value is stored in the storage unit 102.
[0029]
Therefore, when the pressure contact force of the semiconductor stack 10 is adjusted within the range of P1kN to P2kN, the strain detected by each strain gauge 78 and its average strain are set within the range of δ1 μS (microstrain) to δ2 μS. Adjust it.
[0030]
Next, the operation of tightening the semiconductor stack 10 to a predetermined load amount will be described below with reference to the flowchart shown in FIG.
[0031]
First, in the stacking direction of the semiconductor stack 10 (in the direction of arrow A), for example, a pre-pressurization of P3 kN is applied (step S1), and the fastening bolt 56 is temporarily tightened via a torque wrench or the like (step S1). S2). After this temporary tightening operation is completed, the pre-pressurization is released (step S3), and tightening of each tightening bolt 56 is started (step S4).
[0032]
When the tightening bolt 56 is tightened, the disc spring 72 is deformed, and an output value from each strain gauge 78 attached to the disc spring 72 is sent to the control unit 92 constituting the pressurizing force management device 90. It is done. Then, the strain data determination unit 94 determines whether or not the output value from each strain gauge 78 and the average value thereof are within a predetermined range, that is, within the range of δ1 μS to δ2 μS (step S5). The tightening operation of the tightening bolt 56 is performed so as to be inside.
[0033]
As described above, in the first embodiment, four strain gauges 78 are arranged on the surface of the disc spring 78 in the semiconductor stack 10, and the tightening bolt is monitored while monitoring the strain data detected by the strain gauge 78. 56 tightening operations are performed. Since the strain data detected by the strain gauge 78 is set as a linear function of the applied pressure (pressure contact force) acting on the stacked body 50 (see FIG. 6), the strain data acting on the stacked body 50 from the strain data. Pressure can be easily obtained.
[0034]
Thereby, by using the strain gauge 78, the effect that the applied pressure which acts on the laminated body 50 can be adjusted with high precision and easily is acquired. In addition, it is only necessary to incorporate a strain gauge 78 in the semiconductor stack 10, and the semiconductor stack 10 as a whole can be made compact, and the pressing force of the stacked body 50 can be accurately adjusted with a simple and inexpensive configuration. Is possible.
[0035]
Furthermore, in the first embodiment, it is possible to automatically detect that an abnormality has occurred in the semiconductor stack 10 when performing resistance welding work on a workpiece (not shown) by the resistance welder 12. That is, when the operation of the resistance welder 12 is started (step S10 in FIG. 8), the pressure management device 90 outputs the strain gauge 78 detected from the strain gauge 78 via the strain data determination unit 94. It is determined whether or not the value and the average value of each output value are within a predetermined range (step S11). When at least one of the output value of each strain gauge 78 and the average value thereof deviates from the predetermined range, the process proceeds to step S12 and a warning signal is output via the warning signal output unit 100.
[0036]
Thereby, during operation of the semiconductor stack 10, for example, when the tightening bolt 56 is loosened due to an external impact or the like, the slack of the tightening bolt 56 can be easily and reliably detected. Furthermore, the operation of the resistance welding machine 12 is stopped via the control unit 92, or an abnormality warning is displayed.
[0037]
On the other hand, if the output value and the average value of the strain gauge 78 are within the predetermined range (YES in step S11), the process proceeds to step S13 to determine whether or not the operation is finished. If the operation is continued (NO in step S13), the process returns to step S11 and the abnormality detection process of the semiconductor stack 10 is performed.
[0038]
FIG. 9 is an explanatory diagram of a schematic configuration of a resistance welder 123 in which the semiconductor stack 120 and the pressure management device 122 according to the second embodiment of the present invention are assembled. Note that the same components as those of the semiconductor stack 10 and the pressurizing force management device 90 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0039]
The semiconductor stack 120 includes a thermistor (temperature detector) 124 incorporated in the cooling fin 44, for example, in order to detect the ambient temperature of the strain gauge 78. The temperature data detected by the thermistor 124 is sent to the control unit 125 that constitutes the pressure management device 122.
[0040]
The control unit 125 corrects the distortion data based on the temperature data detected by the thermistor 124, and determines whether or not the correction distortion data is within a predetermined range. A correction distortion data determination unit 128 and a warning signal output unit 100 that outputs a warning signal when it is determined that the correction distortion data has deviated from a predetermined range. Instead of using the corrected distortion data determining unit 128, the distortion data determining unit 94 may also serve as the corrected distortion data determining unit.
[0041]
The temperature characteristics of the strain gauge 78 have a relationship between temperature and Δ strain value as shown in FIG. The correction unit 126 corrects the distortion data based on this temperature characteristic to obtain desired corrected distortion data.
[0042]
In the second embodiment configured as described above, as shown in FIG. 11, the ambient temperature of the strain gauge 78 is detected via the thermistor 124 (step S1a), and the strain data is corrected based on this temperature data. Correction distortion data is calculated (step S2a). Therefore, as in the first embodiment, the pre-pressurization is applied to the semiconductor stack 120 (step S3a), and the tightening bolt 56 is temporarily tightened (step S4a).
[0043]
Next, after the pre-pressurization is released (step S5a), the tightening operation of the tightening bolt 56 is performed (step S6a), and the output value of the strain gauge 78 and the average value of each output value are the corrected strain data. A determination is made as to whether or not it is within a predetermined range (step S7a). Then, when the output value and the average value thereof are within the predetermined range (YES in step S7a), the tightening operation of the semiconductor stack 120 is completed.
[0044]
As described above, in the second embodiment, the ambient temperature of the strain gauge 78 is detected via the thermistor 124, and based on this ambient temperature, the strain data detected by the strain gauge 78 is corrected to correct the corrected strain. Data is available. Therefore, there is an effect that the semiconductor stack 120 can be reliably adjusted with a desired applied pressure via the strain gauge 78 without being affected by the ambient temperature of the strain gauge 78.
[0045]
Next, control when the semiconductor stack 120 is operated will be described with reference to FIG.
[0046]
When the operation of the resistance welder 123 is started (step S10a), the temperature detection by the thermistor 124 is performed in the semiconductor stack 120 (step S11a). Then, the distortion data is corrected based on the temperature data detected by the thermistor 124, and corrected distortion data is calculated (step S12a).
[0047]
Therefore, the strain data detected by the strain gauge 78 is sent to the corrected strain data determining unit 128 as corrected strain data, and the corrected strain data determining unit 128 determines whether or not the corrected strain data is within a predetermined range. Is determined (step S13a). When the corrected distortion data deviates from the predetermined range, the process proceeds to step S14a and a warning signal is output.
[0048]
On the other hand, if the corrected distortion data is within the predetermined range, the process proceeds to step S15a to determine whether or not the operation is finished. At that time, if the operation is continued, the process returns to step S11a and the above processing is repeated.
[0049]
Thus, in the second embodiment, the ambient temperature of the strain gauge 78 is detected in the semiconductor stack 120 via the thermistor 124 during the operation of the resistance welder 123. Then, the strain data detected by the strain gauge 78 is corrected to obtain corrected strain data, and it is determined whether or not the corrected strain data is within a predetermined range. For this reason, for example, when the tightening bolt 56 is slack due to an external impact or the like, or when a cooling abnormality due to thermal expansion of the semiconductor element 36 occurs, the correction distortion data determination unit 128 can be used easily and reliably. Can be detected.
[0050]
Furthermore, since a warning signal is output from the warning signal output unit 100 in the event of an abnormality, the warning signal is fed back to the control unit 125 that controls the semiconductor stack 120, or an abnormal warning is displayed, so that a high-quality welding operation is performed. Can be effectively performed.
[0051]
In the first and second embodiments, the four strain gauges 78 are affixed to the disc spring 72. However, the present invention is not limited to this, and three or more strain gauges 78 may be provided. Further, it is determined whether or not the output value from each strain gauge 78 and the average value thereof are within a predetermined range, but only one of the output value or the average value is used to be within the predetermined range. It may be determined whether or not. Furthermore, as the strain detector, an electrostrictive element or the like other than the strain gauge 78 may be used.
[0052]
【The invention's effect】
In the semiconductor stack according to the present invention, at least three strain detectors are arranged on the surface of a disc spring that pressurizes a stacked body in which a plurality of cooling fins and flat semiconductor elements are alternately stacked in the stacking direction. The tightening bolt is tightened while monitoring the strain data detected by the strain detector. Thereby, it is possible to adjust the pressure applied to the stacked body with high accuracy with a simple and small configuration.
[0053]
In the semiconductor stack pressure management apparatus according to the present invention, each strain data detected by the strain detector when the tightening bolt is tightened while monitoring the strain data detected by the strain detector. Is determined to be within a predetermined range. For this reason, the adjustment operation of the applied pressure acting on the laminated body can be easily and reliably performed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration explanatory diagram of a resistance welder assembled with a semiconductor stack according to a first embodiment of the present invention.
FIG. 2 is a front view of a main part of the semiconductor stack.
FIG. 3 is an exploded perspective view of the semiconductor stack.
FIG. 4 is a front explanatory view of a disc spring and a strain gauge constituting the semiconductor stack.
FIG. 5 is a configuration diagram for calculating a relationship between detected strain data of the strain gauge and a load.
FIG. 6 is an explanatory diagram showing a relationship between the strain data and a pressing force measured by a load cell.
FIG. 7 is a flowchart of a tightening operation of the semiconductor stack.
FIG. 8 is a flowchart for explaining the operation of the pressure control device when the resistance welder is operated.
FIG. 9 is a schematic configuration explanatory diagram of a resistance welder in which a semiconductor stack and a pressure management device according to a second embodiment of the present invention are assembled.
FIG. 10 is an explanatory diagram of temperature characteristics of the strain gauge.
FIG. 11 is a flowchart illustrating a tightening operation of the semiconductor stack.
FIG. 12 is a flowchart for explaining the operation of the semiconductor stack pressing force management apparatus;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10, 120 ... Semiconductor stack 12 ... Resistance welding machine 20 ... Welding transformer 32, 34 ... Cooling fin 36 ... Semiconductor element 38, 40, 42, 44 ... Cooling fin 46 ... Electrode plate 48 ... Insulating member 50 ... Laminate 52, 54 ... support plate 56 ... clamping bolt 58 ... flow path 72 ... disc spring 78 ... strain gauges 80a to 80c ... insulating plates 90, 122 ... pressure management devices 92 and 125 ... control part 94 ... strain data judgment part 100 ... warning signal output Unit 102 ... Storage unit 124 ... Thermistor 126 ... Correction unit 128 ... Correction distortion data determination unit

Claims (6)

A laminated body in which a plurality of cooling fins in which cooling medium flow paths are formed and flat semiconductor elements are alternately laminated is sandwiched by fixing members from both sides in the stacking direction, and a plurality of the fixing members are sandwiched between them. A semiconductor stack that is integrally fixed with a fastening bolt of a book,
A disc spring disposed coaxially on the central axis of the laminate and pressurizing the laminate in the laminating direction;
On the surface of the disc spring, at least three strain detectors arranged at regular intervals on a circumference centered on the central axis;
A semiconductor stack comprising: 2. The semiconductor stack according to claim 1, further comprising a temperature detector that detects an ambient temperature of the strain detector. A laminated body in which a plurality of cooling fins in which cooling medium flow paths are formed and flat semiconductor elements are alternately laminated is sandwiched by fixing members from both sides in the stacking direction, and the fixing members are tightened. A pressure control device for a semiconductor stack that is integrally fixed with a bolt,
Coaxially disposed on the central axis of the laminated body and arranged on a surface of a disc spring that pressurizes the laminated body in the laminating direction, spaced apart at equal intervals on a circumference centered on the central axis. At least three strain detectors,
A distortion data determination unit that determines whether each distortion data detected by the distortion detector is within a predetermined range;
A pressure management apparatus for a semiconductor stack, comprising: 4. The pressure management apparatus for a semiconductor stack according to claim 3, further comprising a warning signal output unit that outputs a warning signal when it is determined that the strain data has deviated from a predetermined range. . The pressure detector according to claim 3, wherein the temperature detector detects an ambient temperature of the strain detector;
A correction unit that corrects the distortion data based on the temperature data detected by the temperature detector and obtains corrected distortion data;
A correction distortion data determination unit for determining whether or not the correction distortion data is within a predetermined range;
A pressure management apparatus for a semiconductor stack, comprising: 6. The pressurizing pressure management apparatus according to claim 5, further comprising a warning signal output unit that outputs a warning signal when it is determined that the corrected strain data has deviated from a predetermined range. apparatus.

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