JPH079384Y2 - Semiconductor conversion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a semiconductor conversion device in which a semiconductor element and a cooling fin for cooling the semiconductor element are combined.

(Prior Art) Conventionally, a semiconductor conversion device has been composed of a plurality of flat thyristors and GTs.
The power capacity is increased by alternately superimposing O etc. on the cooling fins. An example of this is the semiconductor conversion device 1 shown in FIGS. 4 and 5. The device main body 2 of the semiconductor conversion device 1 is formed by alternately stacking four semiconductor elements 3 such as thyristors and GTOs with five cooling fins 4. Insulators 5a and 5b are adjacent to the outer sides of the cooling fins 4 at both ends of the apparatus main body 2 stacked in this way. The outer side surface of one insulator 5a is in contact with one mounting plate 6a, and the center portion of the outer side surface of the other insulator 5b is in contact with a conical seat 8 fixed to the pressure plate 7. The pressure plate 7 is adjacent to the other mounting plate 6b via the disc spring 9. Further, through holes 10 are formed on both sides of each cooling fin 4 with the axis of the device body 2 interposed therebetween.
A tightening member 11 is inserted in 10. The fastening member 11 is formed by inserting a shaft 13 in contact with the inner peripheral surface of an insulating tube 12. The shaft 13 has a head 14 at one end and a screw at the other end. This shaft 13 projects from one mounting plate 6a to the outside of the other mounting plate 6b,
The other end of the shaft 13 is screwed with a nut 15.
By this screw tightening, the semiconductor element 3 and the cooling fin 4 are assembled by receiving the pressure between the conical seat 8 and the one mounting plate 6a. At this time, the disc spring 9 acts to adjust the pressure so that the semiconductor element 3 and the cooling fin 4 receive a predetermined pressure, and also acts to absorb the pressure in accordance with the expansion and contraction of the semiconductor element 3 and the cooling fan 4. . Such a semiconductor conversion device 1 is provided between the inner peripheral surface of the through hole 10 of the cooling fin 4 and the outer peripheral surface of the shaft 13 as shown in the sectional view of FIG. In this state, two types of media, air 16 and insulating tube 12, are interposed. That is, the insulation between the cooling fins 4 and the shaft 13 is the insulation by the air 16 and the insulation tube 12.

As shown in FIG. 5, the electric field strengths on the surfaces of the shaft 13 and the insulating tube 12 are the radius r _{1 of the} shaft 13 and the radius of the insulating tube 12, respectively.
r ₂ , radius r ₃ of the through hole 10 of the cooling fin 4, air permittivity ε
₁ , obtained as a function of the dielectric constant ε ₂ of the insulating tube 12. now,
The shaft 13 has a diameter of 8 to 16 mm, and the insulating tube 12 has a dielectric constant of 4 to
If the value is 5, the electric field strength on the surface of the shaft 13 is the highest,
The electric field strength E is obtained by the following formula.

E = V / {(1 / ε ₁ lur ₂ / r ₁ ) + (1 / ε ₂ lur ₃ / r ₂ )} ε ₁ r
₁ Generally, the dielectric strength of an insulator is larger than that of air, but if the gap G1 between the through hole 10 of the cooling fin 4 and the insulating tube 12 is small, the air strength E of the above formula becomes about 30 kv / cm
Only part of it is destroyed resulting in a corona discharge. When the corona discharge is generated in this manner, the insulating tube 12 may be affected and deteriorate.

However, in the semiconductor conversion device 1 having the above-described configuration, in order to prevent the occurrence of corona discharge, the through hole 10 of the cooling fin 4 is formed.
And the diameter of the shaft 13 are set to predetermined values.
Also, when assembling the semiconductor conversion device 1, the through hole 10
And the shaft 13 so as not to be eccentric, a gap G1 between the outer peripheral surface of the insulating tube 12 and the inner peripheral surface of the through hole 10 using a jig, and
The gap G2 between the inner peripheral surface of the through hole 10 and the outer peripheral surface of the shaft 13 is kept constant (problems to be solved by the invention). However, in the above-described configuration of the conventional semiconductor conversion device 1, jigs and tools are used. Even if it is used, it is very difficult to assemble it so that the gap G1 between the inner peripheral surface of the through hole 10 of the cooling fin 4 and the outer peripheral surface of the insulating tube 12 is kept constant. Since it is loosened, the through hole 10 and the shaft 13 are eccentric, and the shaft 13 may come into contact with the inner peripheral surface of the through hole 10. The adjustment work time for avoiding this contact is wasted, and if the semiconductor element 3 is replaced while the semiconductor conversion device 1 is attached to the control panel, the inner peripheral surface of the through hole 10 and the insulating pipe 12 are not replaced. It is not possible to confirm the distance G1 from the outer peripheral surface.

The present invention has been made to solve the above problems, and can always and accurately maintain the distance between the inner peripheral surface of the through hole of the cooling fin and the outer peripheral surface of the tightening member. It is an object of the present invention to provide a semiconductor conversion device that can be easily manufactured.

[Constitution of device]

(Means for Solving the Problems) In order to achieve the above object, the present invention forms an apparatus main body in which flat semiconductor elements and cooling fins for cooling the semiconductor elements are alternately stacked, and one end of the apparatus main body is formed. A semiconductor conversion device in which a fastening member having a shaft inserted into an insulating pipe is projected to the other end of the device body through a through hole formed in each cooling fin, and the device body is fastened by the fastening member. Is an insulating tube inserted in contact with the inner peripheral surface of the through hole formed in each cooling fin, a shaft inserted in this insulating tube, the outer peripheral surface of this shaft and the inner peripheral surface of the insulating tube. And spacers which are arranged at least at two positions with an appropriate interval in the axial direction of the shaft and which keep the outer peripheral surface of the shaft and the inner peripheral surface of the insulating tube at equal intervals. Is.

(Operation) In the tightening member of the semiconductor conversion device having the above-described configuration, the shaft is inserted into the insulating pipe inserted into the through hole of each cooling fin, and the shaft and the insulating pipe are connected in the axial direction of the shaft. Spacers are arranged at least at two places between the shafts to keep the outer peripheral surface of the shaft and the inner peripheral surface of the insulating tube at equal intervals.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. First
The drawing shows an embodiment of a fastening member used in the semiconductor conversion device of the present invention. This fastening member is indicated by the arrow A- in FIG.
FIG. 4 is an enlarged sectional view indicated by A, and the present invention also uses FIG. 4 described in the section of the related art. Since the semiconductor conversion device of the present invention has the same configuration as that described in the section of the prior art based on FIGS. 4 and 5, the same reference numerals are given to the configurations and detailed description thereof is omitted. To do.

The tightening member 11 shown in FIG. 1 will be described. First, the tightening member 11 is formed by inserting a shaft 13 having a diameter smaller than the inner diameter of the insulating tube 12 into the insulating tube 12. The insulating tube 12 has an outer diameter dimension close to the inner diameter of the through hole 10 formed in the cooling fin 4, and is inserted in the inner peripheral surface of each through hole 4 in a contact state. The insulating tube 12 has a length from the inside of the one mounting plate 6a to the inside of the other mounting plate 6b. A head 14 is formed at one end of a shaft 13 inserted into the insulating tube 12, and a screw is formed at the other end. Such a shaft 13 is attached to one of the mounting plates 6a through the respective through holes 10
It passes through the inside of the insulating tube 12 inserted into the other side and projects to the outside of the other mounting plate 6b. Shaft 13 inserted in insulation tube 12
Of the insulating fins 5a on one side and the insulating fins 5b on the other side, that is, between the cooling fins 4 arranged on both ends of the apparatus main body 2 and the one mounting plate 6a, and between the pressure plate 7. A spacer ring 17 is attached to the portion of the shaft 13 between them as shown in FIG. This spacer ring 17
Between the cooling fin 4 and the shaft 13, the shaft 13
Is arranged at a position that avoids an increase in electric field strength on the surface of. The spacer ring 17 is made of a plastic material and is mounted in the groove 18 formed in the shaft 13. The spacer ring 17 mounted in this manner is used as the insulating tube 12.
It has elasticity to the inner peripheral surface of the shaft 13
The outer peripheral surface and the inner peripheral surface of the insulating tube 12 are kept at equal intervals. Further, when the semiconductor element 3 is replaced, the screw of the shaft 13 is loosened, and after the replacement, even if the shaft 13 is screwed, the distance between the outer peripheral surface of the shaft 13 and the inner peripheral surface of the insulating tube 12 does not change. Absent. Further, when the cooling fins 4 are replaced, the tightening members 11 are pulled out from the through holes 10 of the respective cooling fins 4, and after the replacement, the tightening members 11 are again inserted into the through holes 10, and even if tightened, the shaft 13 The distance between the outer peripheral surface of the and the inner peripheral surface of the insulating tube 12 does not change.

In the tightening member 11 having the above-described structure, as shown in FIG. ₁ , the radius of the shaft 13 is r ₁ , the radius of the inner circumference of the insulating tube 12 is r ₂ , the outer radius of the insulating tube 12 is r ₃ , and the insulation is Assuming that the permittivity of the tube 12 is ε ₁ and the permittivity of the air 16 is ε ₂ , the electric field intensity E on the surface of the shaft 13 that maximizes the electric field intensity can be obtained by the following equation.

E = V / {(1 / ε ₁ lur ₃ / r ₂ ) + (1 / ε ₂ lur ₂ / r ₁ )} ε ₂ r
_{1 In the} above formula, since the distance between the outer peripheral surface of the shaft 13 and the inner peripheral surface of the insulating tube 12 is always constant, the maximum electric field strength E is 30 kv.
It will never be close to / cm and no corona discharge will occur.

In FIG. 3, a split pin 19 is mounted in the groove 18 formed in the shaft 13 instead of the spacer ring 17 described above.
Even in this case, the outer peripheral surface of the shaft 13 and the inner peripheral surface of the insulating tube 12 can be kept at equal intervals, as in the above-described embodiment.

In each of the above embodiments, the spacer ring 17 and the split pin 19 were mounted in the groove 18 of the shaft 13, but the insulating tube
It may be attached to the inner peripheral portion of 12.

[Effect of device]

From the above description, the fastening member of the semiconductor conversion device according to the present invention inserts the insulating pipe in a state of being in contact with the inner peripheral surface of the through hole formed in each cooling fin, and inserting the shaft in the insulating pipe. The spacers at appropriate intervals in the axial direction of the shaft, and at least two spacers are arranged between the outer peripheral surface of the shaft and the inner peripheral surface of the insulating pipe. Since they can be kept at equal intervals, the distance between the outer peripheral surface of the shaft and the inner peripheral surface of the insulating pipe can be always and accurately maintained, and the outer peripheral surface of the shaft and the inner peripheral surface of the insulating pipe can be maintained. Since the work of adjusting the interval between and is unnecessary, it is possible to realize a semiconductor conversion device that is easy to assemble.

[Brief description of drawings]

FIG. 1 shows a fastening member of a semiconductor conversion device of the present invention, and an arrow A- in FIG. 4 sharing the drawing of the conventional semiconductor conversion device.
FIG. 4 is an enlarged sectional view indicated by A, and FIG. 2 is an arrow C in FIG.
FIG. 3 is an enlarged cross-sectional view of a portion shown by, FIG. 3 is an enlarged cross-sectional view showing another example of the portion shown by arrow C in FIG. 4, FIG. 4 is a plan view showing a semiconductor conversion device, and FIG. FIG. 5 is an enlarged cross-sectional view of the fastening member of FIG. 4 indicated by an arrow BB in FIG. 4. 1 ... Semiconductor conversion device, 2 ... Device body, 3 ... Semiconductor element, 4 ... Cooling fin, 10 ... Through hole, 11 ... Tightening member, 12 ... Insulation pipe, 13 ... Shaft, 17 , 19 …… Spacer (spacer ring, cotter pin).

Claims (2)

[Scope of utility model registration request] 1. A device main body is formed by alternately stacking flat semiconductor elements and cooling fins for cooling the semiconductor elements,
A fastening member having a shaft inserted into an insulating tube from one end of the device body is projected to the other end of the device body through a through hole formed in each cooling fin, and the device body is fastened by the fastening member. In the semiconductor conversion device, the fastening member includes an insulating tube inserted in a state of being in contact with an inner peripheral surface of the through hole formed in each cooling fin, a shaft inserted in the insulating tube, and the shaft. Between the outer peripheral surface of the shaft and the inner peripheral surface of the insulating pipe, and at least at two positions with an appropriate distance in the axial direction of the shaft, the outer peripheral surface of the shaft and the inner peripheral surface of the insulating pipe. A semiconductor conversion device, characterized in that it is provided with spacers that keep the spaces at equal intervals. 2. The spacer is arranged between the outer peripheral surface of the shaft and the inner peripheral surface of the insulating pipe and at a position separated from at least two through holes of the cooling fin in the axial direction of the shaft. The semiconductor conversion device according to claim 1.