Patent Application
20200088257
The present invention relates to a pressing structure and a pressing unit.
A spring member, which is provided between two pressed bodies, and presses one or both of these pressed bodies by applying pressure thereto, has been known. This spring member is used in, for example, a power converting apparatus having a stacked structure formed by alternately stacking semiconductor modules and cooling tubes that cool the semiconductor modules on each other (see, for example, Patent Literature 1).
This power converting apparatus includes: at a stacking direction end portion of the semiconductor modules and cooling tubes, a spring member that generates pressing force along a stacking direction; and an abutting plate, which is provided between this spring member and the stacked structure, and is for generating a uniform pressing force in the stacking direction. A power converting apparatus having such a configuration enables its semiconductor modules to be sufficiently cooled, because adjacent ones of the semiconductor modules and cooling tubes closely contact each other by means of the pressing force of its spring member.
Patent Literature 1: Japanese Laid-open Patent Publication No. 2014-011936
Demanded for a spring member for a pressing use as described above are: a long elastic stroke relative to a load for absorption of the tolerance or the like of a target to be pressed; and pressing in a uniform surface pressure distribution while generating a uniform stress. Methods of increasing the length of the elastic stroke include a method where plural plate-like spring members are placed on top of one another in a stroke direction. However, hysteresis caused by friction between the spring members and complexity of the assembly are problematic, making it impossible to place too many spring members on top of one another and limiting the possible range of increase in the length of the elastic stroke.
The present invention has been made in view of the above, and an object thereof is to provide a pressing structure and a pressing unit that have a long elastic stroke relative to a load and are able to press a target while generating a uniform stress.
To solve the above-described problem and achieve the object, a pressing structure according to the present invention is arranged between a first pressed body and a second pressed body opposite to the first pressed body and presses the first pressed body and the second pressed body, and includes a spring member including: a base portion formed of a single strip-like member and having a curved principal surface; two extended portions extending respectively from end portions of the base portion and curved in a form inverse of a curving form of the base portion; and two bent portions extending respectively from end portions of the two extended portions, the end portions being at sides opposite to sides connected to the base portion, the two bent portions being curved in a form inverse of the curving form of the extended portions, wherein a maximum thickness of the extended portions and bent portions is smaller than a maximum thickness of the base portion.
Moreover, in the above-described pressing structure according to the present invention, the base portion decreases in thickness toward the extended portions.
Moreover, in the above-described pressing structure according to the present invention, a locus formed of a collection of curvature center points of one of principal surfaces of the base portion and a locus formed of a collection of curvature center points of the other principal surface are different from each other.
Moreover, in the above-described pressing structure according to the present invention, a ratio, d1/d2, between the maximum thickness d1 of the base portion and the maximum thickness d2 of the extended portions and bent portions is equal to or larger than 1.5 and equal to or smaller than 3.0.
Moreover, in the above-described pressing structure according to the present invention, on a side surface connected to two opposite principal surfaces of the spring member, the side surface being at a side that is curved according to the curving forms of the base portion, extended portions, and bent portions, a shear surface is formed only on a principal surface side where the base portion and bent portions are concave and a fracture surface is formed only on a principal surface side where the base portion and bent portions are convex.
Moreover, a pressing unit according to the present invention includes: a first pressed body; a second pressed body arranged opposite to the first pressed body; and the pressing structure according to the above-described invention that is arranged between the first pressed body and the second pressed body and presses the first pressed body and the second pressed body.
The present invention has an effect of achieving a long elastic stroke relative to a load and enabling a target to be pressed while a uniform stress is being generated.
Described in the following description as modes for carrying out the present invention (hereinafter, referred to as “embodiments”) are pressing units each having a spring member used therein. Furthermore, the invention is not limited by these embodiments. Moreover, throughout the drawings, any portions that are the same are assigned with the same reference sign. In addition, it needs to be noted that the drawings are schematic, and that relations between thicknesses and widths of components, and ratios or the like among the components are different from the actual ones. Furthermore, the drawings include a portion that differs in dimensions and ratios among the drawings. Dimensions or the like “being equivalent” means that the dimensions or the like are equivalent in terms of design, and dimensions or the like of the actual components include manufacturing errors.
The spring member 1 is manufactured by bending a strip-like member formed of a single plate that partially differs in thickness. The single plate referred to herein means a plate formed of a single member, and not a plate having plural members integrated together by bonding or sticking. Hereinafter, in each member, a surface having a relatively large area will be referred to as a “principal surface”, and a surface orthogonal to the principal surface will be referred to as a “side surface”. Furthermore, a length between the principal surfaces (the length in a Z-direction in
The spring member 1 has: a base portion 10 that has an outer margin forming a rectangular shape (a shape on an XY-plane in
The base portion 10 is curved in an arc-shape having curvature centers on one side of principal surfaces that are opposite to each other in a plate thickness direction when viewed from the Y-direction (
The base portion 10 applies a load to the second pressed body 102 by coming into contact with the second pressed body 102, at the central portion along a longitudinal direction thereof. Curvature of the base portion 10 is able to be designed according to an interval between the first pressed body 101 and the second pressed body 102, and a length thereof in the X-direction, as appropriate.
By coming into contact with the first pressed body 101, the extended portions 11 and 12 apply a load to the first pressed body 101. The extended portions 11 and 12 have thicknesses equivalent to each other, and this thickness d2 of the extended portions 11 and 12 is smaller than a thickness d1 of the connection direction central portion of the base portion 10 (see
The bent portions 13 and 14 form end portions of the spring member 1, and are portions that are, for example, held by a user or engaged with a member. The bent portions 13 and 14 have thicknesses that are equivalent to each other, and the maximum thickness of the bent portions 13 and 14 may be equivalent to, smaller than, or larger than the thickness d2 of the extended portions 11 and 12. The bent portions 13 and 14 may extend in a uniform thickness, or partially change in thickness.
As illustrated in
As described above, since the spring member 1 is shaped to decrease in thickness toward the extended portions 11 and 12 from the central portion of the base portion 10; the curvature, at which the extended portions 11 and 12 are able to be bent, is able to be increased as compared to a case where the whole spring member 1 has a uniform thickness, for example, as compared to a case where the extended portions 11 and 12 have the thickness d1 of the base portion 10, while the base portion 10 maintains the load applied to the second pressed body 102. By increasing the curvature of the extended portions 11 and 12, a proportion of the extended portions 11 and 12 in the spring member 1 is able to be decreased and a proportion of the base portion 10 in the spring member 1 is able to be increased. By the increase in the proportion of the base portion 10 in the spring member 1, length of the elastic stroke is able to be increased.
A ratio d1/d2 between the thickness d1 of the connection direction central portion of the base portion 10 and the thickness d2 of the extended portions 11 and 12 is preferably equal to or larger than 1.5 and equal to or smaller than 3.0. The thicknesses referred to herein mean the maximum thicknesses of the base portion 10 and the extended portions 11 and 12. The thickness d2 may be the maximum thickness in the extended portions 11 and 12 and bent portions 13 and 14. If d1/d2 is smaller than 1.5, the difference between the thicknesses becomes small, and the effect of increasing the curvature of the extended portions 11 and 12 as described above may be unable to be obtained. Furthermore, if d1/d2 is larger than 3.0, the thickness of the connection direction central portion of the base portion 10 becomes too large and flexibility of the base portion 10 itself may be lost.
The spring member 1 is manufactured by bending this base material 20 to sides (arrows illustrated in
Specifically, as illustrated in
Thereafter, a base material 130 is punched out by pressing the plate-like member 120 in a direction of an arrow F2, that is, in the same direction as the pressing direction for the slits 120a and 120b (see
When slits are formed by pressing, the above described fracture surface and shear surface are generated according to the direction of the pressing.
As the punch 153 is continuously lowered, the knockout 151 is lowered while the material is deformed (see
As the punch 153 is lowered further, the material 140 is cut and divided into a first material 141 and a second material 142 (see
Since the base material 130 has been conventionally formed by performing punching from two opposite directions as described above, the fracture surface and shear surface at both longitudinal direction end portions of the base material 130 are formed on the surface opposite to the surface where the fracture surface and shear surface are formed at a portion other than these end portions. Thereby, the fracture surfaces Br11 and Br12 and shear surfaces Dr11 and Dr12 as illustrated in
According to the above described first embodiment, in the spring member 1, since the thickness of the extended portions 11 and 12 is made small as compared to the thickness of the base portion 10, and the curvature, at which the extended portions 11 and 12 are able to be bent, is made large as compared to the curvature, at which the base portion 10 is able to be bent, the elastic stroke relative to a load on the first pressed body 101 and second pressed body 102 is long, and a target is able to be pressed while a uniform stress is being generated.
Conventionally known as another method of increasing the length of the elastic stroke is a method where stress is uniformized and the length of elastic stroke is increased by making a target to be pressed tapered at a side where the target to be pressed comes into contact with the first pressed body 101. In this method, the closer the width of the distal end portion is to zero, the higher the stress uniformization effect is. However, when this method is additionally used, the tapered distal end portion comes into contact with the target to be pressed, and thus there is a problem that the surface pressure is increased due to the decrease in the contact area. In contrast, when the spring member 1 according to the first embodiment is formed of a member having a uniform width, the increase in the surface pressure is able to be prevented.
In the above described spring member 1 according to the first embodiment, the width of the extended portion 11 and bent portion 13, and the width of the extended portion 12 and bent portion 14 may be continuously or stepwisely increased from the sides connected the base portion 10 to end portions of the bent portions 13 and 14, the end portions being at sides opposite to sides respectively connected to the extended portions 11 and 12, or the width of the bent portions 13 and 14 may be made larger than the widths of the base portion 10 and extended portions 11 and 12.
Furthermore, the above described spring member 1 according to the first embodiment may have a hole provided therein, the hole penetrating therethrough from one of the principal surfaces to the other principal surface. By the formation of the hole, weight reduction of the spring member 1 is able to be achieved.
Furthermore, according to the above description of the first embodiment, the spring member 1 is formed by using the base material 20 having the inclined surfaces 22a and 23a provided on one of the principal surfaces, but the first embodiment is not limited to this formation.
Furthermore, as illustrated in
In the base material 20B illustrated in
Next, a second embodiment of the present invention will be described.
The power converting apparatus 200 includes: a semiconductor stack unit (first pressed body) 202 including semiconductor elements; the spring member 1 that presses the semiconductor stack unit 202 from one of side surfaces thereof; an abutting plate 204 that is interposed between the semiconductor stack unit 202 and the spring member 1 and is plate-like; and a housing (second pressed body) 205 that accommodates therein the semiconductor stack unit 202, the spring member 1, and the abutting plate 204. Additionally to those illustrated in
The semiconductor stack unit 202 has a structure where the semiconductor modules 221 and cooling tubes 222 are alternately stacked on each other. In the case illustrated in
The semiconductor module 221 is integrally formed by: having an IGBT element and a flywheel diode element that are arranged between a pair of radiator plates, the IGBT element being for electric power supply, the flywheel diode element being provided for smoothly rotating the motor; and being sealed by resin such that the pair of radiator plates are exposed.
The cooling tube 222 is a flat-shaped tube having a refrigerant flow channel inside. For example, a cooling medium, such as: a natural refrigerant, such as water or ammonia; water mixed with an ethylene glycol-based antifreeze; a fluorocarbon-based refrigerant, such as Fluorinert; a fluorocarbon refrigerant, such as HCFC123 or HFC134a; an alcohol-based refrigerant, such as methanol or alcohol; or a ketone-based refrigerant, such as acetone, is caused to flow through the refrigerant flow channel.
The plural cooling tubes 222 are connected to one another via connecting pipes 223 extending along the stacking direction of the semiconductor stack unit 202. End portions of the connecting pipes 223 have, provided therein, a refrigerant introduction port 224 and a refrigerant discharge port 225, which are connected to the cooling tube 222 arranged at these end portions. The cooling tubes 222, the connecting pipes 223, the refrigerant introduction port 224, and the refrigerant discharge port 225 are realized by use of, for example, aluminum.
Principal surfaces 222a of the cooling tubes 222 are in close contact with the radiator plates of the semiconductor modules 221, due to the pressing force from the spring member 1. Thereby, heat exchange between the semiconductor modules 221 and the cooling tubes 222 is able to achieved.
The spring member 1 is supported by: the base portion 10 abutting the abutting plate 204; and the bent portions 13 and 14 being engaged with the supporting members 206.
According to the above described second embodiment, by use of the spring member 1, the semiconductor stack unit 202 is able to be pressed in its stacking direction by sufficient pressing force. Therefore, cooling efficiency of the semiconductor stack unit 202 by means of the cooling tubes 222 is able to be improved.
A power converting apparatus 200A according to this modified example includes, instead of the supporting members 206 of the above described power converting apparatus 200, supporting members 207. Inside the housing 205, the supporting members 207 each extend in a pillar-shape and each have an extending direction distal end forming a plane.
The spring member 1 is sandwiched by: the base portion 10 abutting the abutting plate 204; and the extended portions 11 and 12 abutting the supporting members 207.
According to the above described modified example of the second embodiment also, by using the spring member 1, the semiconductor stack unit 202 is able to be pressed in its stacking direction by sufficient pressing force. Therefore, cooling efficiency of the semiconductor stack unit 202 by means of the cooling tubes 222 is able to be improved.
Described next is a third embodiment of the present invention.
An electric double layer capacitor 250 according to the third embodiment of the present invention includes: a cell stack (first pressed body) 252 including plural package cells 251; the spring member 1 that presses the cell stack 252 from one of side surfaces thereof; an abutting plate 254 that is interposed between the cell stack 252 and the spring member 1 and is plate-like; and a housing (second pressed body) 255 that accommodates therein the cell stack 252, the spring member 1, and the abutting plate 254. The housing 255 has, provided therein, supporting members 256, which hold and support the spring member 1 between the supporting members 256 and the abutting plate 254 and are cylindrical. The electric double layer capacitor 250 has, additionally to those illustrated in
The cell stack 252 is formed by stacking the plural package cells 251 together. Each of the package cells 251 has an innermost layer and an outermost layer that are formed of insulating films, and includes a positive collector electrode and a negative collector electrode. Each of the package cells 251 accommodates therein, together with an electrolyte, a stack having plural collector electrodes placed on top of one another via separators. A positive electrode terminal and a negative electrode terminal of each of the collector electrodes are respectively connected to the positive collector electrode and the negative collector electrode. The plural package cells 251 are connected in series by connection between positive collector electrodes and negative collector electrodes of adjacent ones of the package cells 251 via connection terminals.
The spring member 1 is supported by: the base portion 10 abutting the abutting plate 254; and the bent portions 13 and 14 engaging with the supporting members 256.
According to the above described third embodiment, by the spring member 1 pressing the cell stack 252 of the electric double layer capacitor 250 in its stacking direction and limiting expansion of the polarizable electrode, the energy density per unit volume is able to be improved.
A pressing unit, to which the spring member 1 according to the first embodiment is applied, may be any pressing unit that has the spring member 1 arranged between a first pressed body and a second pressed body and presses the first pressed body and the second pressed body by means of the spring member 1; although the power converting apparatus according to the above described second embodiment is an example of a pressing unit that requires pressing by the spring member 1, and the electric double layer capacitor according to the above described third embodiment is another example of the pressing unit that requires pressing by means of the spring member 1.
The present invention may thus include various embodiments and the like not described herein, and various design changes and the like within the scope not departing from the technical ideas specified by the claims may be made.
As described above, a pressing structure and a pressing unit according to the present invention have a long elastic stroke relative to a load and are suitable for pressing a target while generating a uniform stress. Reference Signs List
1 SPRING MEMBER
10, 21, 21A BASE PORTION
11, 12 EXTENDED PORTION
13, 14 BENT PORTION
20, 20A, 20B BASE MATERIAL
22, 22A, 22B, 23, 23A, 23B INCLINED PORTION
24, 25 END PORTION
100 PRESSING STRUCTURE
101 FIRST PRESSED BODY
102 SECOND PRESSED BODY
200 POWER CONVERTING APPARATUS
202 SEMICONDUCTOR STACK UNIT
204, 254 CONTACTING PLATE
205, 255 HOUSING
221 SEMICONDUCTOR MODULE
222 COOLING TUBE
223 CONNECTING PIPE
224 REFRIGERANT INTRODUCTION PORT
225 REFRIGERANT DISCHARGE PORT
250 ELECTRIC DOUBLE LAYER CAPACITOR
251 PACKAGE CELL
252 CELL STACK
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-237709 | Dec 2016 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2017/043879 | 12/6/2017 | WO | 00 |
