WO2022254971A1 - ロードセル - Google Patents

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Publication number
WO2022254971A1
WO2022254971A1 PCT/JP2022/017557 JP2022017557W WO2022254971A1 WO 2022254971 A1 WO2022254971 A1 WO 2022254971A1 JP 2022017557 W JP2022017557 W JP 2022017557W WO 2022254971 A1 WO2022254971 A1 WO 2022254971A1
Authority
WO
WIPO (PCT)
Prior art keywords
cable
strain
ferrule
load cell
flange portion
Prior art date
Application number
PCT/JP2022/017557
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
道伯 稲森
Original Assignee
ミネベアミツミ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ミネベアミツミ株式会社 filed Critical ミネベアミツミ株式会社
Publication of WO2022254971A1 publication Critical patent/WO2022254971A1/ja

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/26—Auxiliary measures taken, or devices used, in connection with the measurement of force, e.g. for preventing influence of transverse components of force, for preventing overload

Definitions

  • the present invention relates to load cells.
  • a bridge circuit is formed by inserting an electric cable into a cable insertion hole opened in a side surface of a fixed part and connecting the lead wires of the electric cable on the terminal board of the terminal board accommodating part by soldering.
  • the terminal board accommodating portion is sealed by filling with a curable resin (see, for example, Patent Document 1).
  • the present invention has been made in view of the above background, and an object of the present invention is to provide a load cell with a structure that further improves the pulling force of the cable compared to the conventional one.
  • the load cell of the present invention includes a strain body having a through hole formed at a predetermined position, a strain gauge attached to the strain body, and a strain gauge inserted into the inner space of the strain body through the through hole. and a cable having electric wires electrically and physically connected to the strain gauge, wherein the cable is engaged with the strain-generating body at a distal end side inserted into the inner space of the strain-generating body. is formed around the ferrule attached to the periphery of the cable, and around the electric wire passing through the ferrule, the inner diameter of which is larger than the inner diameter of the flange of the ferrule and can be engaged with the flange. and a locking portion.
  • FIG. 1 is a partially enlarged cross-sectional view showing the configuration of a cable according to one embodiment of the invention
  • FIG. It is a figure which shows the production procedure of the cable concerning one embodiment of this invention.
  • FIG. 4B is a top view showing a state before the cable is pulled and a state where the cable is pulled according to the embodiment of the present invention;
  • a load cell (1) includes a strain body (10) having a through hole (10ah) formed at a predetermined position, and a strain body (10) attached to the a strain gauge and a cable (20 ), and the cable (20) is formed with a flange (26) that engages with the strain body (10) at the distal end side inserted into the inner space (10sp) of the strain body (10).
  • a ferrule (22) attached around the cable (20) and an electric wire (25) passing through the inside of the ferrule (22), and is larger than the inner diameter of the flange portion (26) of the ferrule (22) It has a large flange portion (26) and a lockable locking portion (27).
  • the outer diameter of the locking portion (27) is larger than the outer diameter of the flange portion (26).
  • the locking portion (27) preferably has a conical shape.
  • the conical shape of the locking portion (27) has one outer diameter smaller than the inner diameter of the flange portion (26), and the other outer diameter gradually becomes smaller as the distance from the flange portion (26) increases. ).
  • the locking portion (27) is solder.
  • FIG. 1 is a perspective view showing the overall configuration of a load cell according to one embodiment of the invention.
  • FIG. 2 is a partially enlarged sectional view showing the configuration of the cable according to one embodiment of the invention.
  • FIG. 3 is a diagram showing a procedure for creating a cable according to one embodiment of the present invention.
  • FIG. 4 is a top view showing a state before the cable is pulled and a state where the cable is pulled according to one embodiment of the present invention.
  • the load cell 1 detects the internal pressure of a cavity in a mold of an injection molding machine (not shown). Specifically, the load cell 1 measures the internal pressure of a cavity formed by a fixed mold supported by a fixed platen of a mold clamping device of an injection molding machine and a movable mold supported by a movable platen of the mold clamping device. When measuring, it is attached to the rear end face of the ejector pin of the movable mold.
  • the load cell 1 has a metal strain-generating body 10 having an inner space 10sp and a cable 20.
  • the strain-generating body 10 has a cylindrical shape with a bottom and a lid, and has a load receiving portion 11 projecting in a cylindrical shape from the center of an upper lid surface (hereinafter referred to as "upper lid surface") 10b. there is The load receiving portion 11 is brought into contact with the rear end surface of the ejector pin of the movable mold described above.
  • the strain-generating body 10 is not limited to a cylindrical shape, and may be a tubular shape having an inner space 10sp and a rectangular tubular shape.
  • a disk-shaped diaphragm portion (not shown) disposed facing the load receiving portion 11 is provided in the inner space 10sp of the strain generating body 10, and a plurality of strain gauges are attached to the diaphragm portion. ing. A plurality of strain gauges are connected to a printed circuit board (not shown) provided in the inner space 10sp of the strain generating body 10 .
  • the strain generating body 10 has a through hole 10ah penetrating from its outer peripheral surface (hereinafter referred to as "outer peripheral surface") 10a to the inner space 10sp.
  • the inner diameter of this through-hole 10ah is the same as the outer diameter of the ferrule 22 of the cable 20 .
  • Cable 20 is inserted into through hole 10ah of strain body 10 via ferrule 22 .
  • the cable 20 has a shield wire 24 and a plurality of (in this case, four) wires 25 which are surrounded by a heat-resistant and insulating coating 21 made of polytetrafluoroethylene (PTFE), so-called fluororesin. covered. Specifically, it is sufficient that the material has heat resistance against the temperature generated in the mold of the injection molding machine.
  • PTFE polytetrafluoroethylene
  • the cable 20 has a cylindrical ferrule 22 integrally attached to its longitudinal tip.
  • the cable 20 is inserted into the inner space 10sp through a through hole 10ah provided in the outer peripheral surface 10a of the strain generating body 10 together with a ferrule 22 at the tip.
  • the ferrule 22 is a cylindrical metal member attached to the tip of the cable 20 .
  • the ferrule 22 protects the shield wire 24 and the plurality of wires 25 inside the cable 20 .
  • the ferrule 22 may be partially crushed integrally with the shield wire 24 and the electric wire 25 inside. As a result, the ferrule 22 and the shielded wire 24 and the wire 25 inside thereof are integrated, thereby preventing the shielded wire 24 and the wire 25 from being pulled out with the ferrule 22 left.
  • the ferrule 22 is crushed strongly, the insulating layer made of resin will be crushed, the distance between the metal conductors will be reduced, and sufficient insulation will not be ensured, so insulation will not be impaired. It is preferably crushed to some extent. However, in this embodiment, the ferrule 22 does not necessarily have to be crushed.
  • the coating 21, that is, PTFE, which is widely used as an insulator for high temperatures, is made of a material with a low coefficient of friction and is therefore slippery and easy to come off. Difficult to obtain removal force.
  • a flange portion 26 extending in a radial direction perpendicular to the longitudinal direction of the ferrule 22 is formed at the distal end portion of the ferrule 22 .
  • the outer diameter of the flange portion 26 is larger than the inner diameter of the through hole 10ah provided in the outer peripheral surface 10a of the strain body 10. That is, since the flange portion 26 of the ferrule 22 is hooked on the strain body 10 and locked, the ferrule 22 is prevented from being pulled out of the strain body 10 in advance.
  • the electric wire 25 is a lead wire and is physically and electrically connected to the strain gauge attached to the diaphragm portion arranged in the inner space 10sp of the strain generating body 10 .
  • the shield wire 24 is a net-like plated copper wire provided to shield the electric wire 25 from an external magnetic field.
  • the shield wire 24 is cut short after the plated copper wire is unwound.
  • the shield wire 24 is cut to the extent that it slightly protrudes from the end of the covering portion 21 and is expanded in diameter so as to gradually separate from the electric wire 25 .
  • a portion of the shield wire 24 that protrudes from the end of the covering portion 21 and is cut to a predetermined length and enlarged in diameter is referred to as an enlarged diameter portion 24a.
  • the expanded diameter portion 24a of the shield wire 24 is provided with a locking portion 27 that is larger than the inner diameter of the flange portion 26 by soldering so as to cover the entire expanded diameter portion 24a.
  • the outer diameter of the locking portion 27 is larger than the outer diameter of the flange portion 26 .
  • the outer diameter of the locking portion 27 and the outer diameter of the flange portion 26 may be the same. In short, it is sufficient that the locking portion 27 has an outer diameter that can be locked to the flange portion 26 .
  • the locking portion 27 has a shape corresponding to the enlarged diameter portion 24a of the shield wire 24, that is, its cross section has a conical shape.
  • the locking portion 27 is tapered toward the flange portion 26 .
  • the engaging portion 27 has a tapered shape whose diameter increases with distance from the flange portion 26 along the longitudinal direction. That is, the locking portion 27 has a tapered portion 27t with a small diameter and a thick tapered portion 27f with a larger diameter than the tapered portion 27t.
  • the locking portion 27 may have a conical cross-sectional shape in which the solder is formed so as to cover the four electric wires 25 from all directions (360 degrees).
  • the locking portion 27 does not necessarily have a conical cross section, and may have a polygonal pyramid shape such as a hexagonal pyramid shape or an octagonal pyramid shape.
  • a polygonal pyramid shape that is closer to a conical shape than a triangular pyramid shape or a quadrangular pyramid shape is preferable.
  • FIG. 3A a cable 20 is prepared, and only the covering portion 21 is cut to expose the shield wire 24 and four electric wires 25 . At this point, the electric wire 25 is covered with the shield wire 24 .
  • the ferrule 22 is not shown here for convenience.
  • a predetermined length for example, 1 mm to 2 mm
  • the portion of the shielded wire 24 slightly left from the end of the covering portion 21 is unwound to form a diameter-enlarged portion 24a.
  • the four wires 25 inside the shield wire 24 are exposed.
  • the enlarged diameter portion 24a protrudes from the end of the covering portion 21 of the cable 20, and is in a state of being enlarged away from the electric wire 25.
  • a locking portion 27 having a conical cross section is formed.
  • the locking portion 27 can be pulled from all directions (360 degrees) by the flange portion 26. Acts as if tightened.
  • the flange portion 26 of the ferrule 22 does not actively tighten the locking portion 27 directly, if the cable 20 continues to be pulled, the flange portion 26 will tighten the locking portion 27 from the circumferential direction. Become.
  • the locking portion 27 is made of solder, it is tightened while being crushed by the flange portion 26 .
  • the contact area with the flange portion 26 increases, and a stronger locking state is formed. Further, by soldering, it is possible to prevent the conical expanded diameter portion 24a at the end of the shield wire 24 from being reduced in diameter.
  • the cable 20 is pulled from the strain body 10 by the frictional force between the flange portion 26 of the ferrule 22 and the locking portion 27 of the cable 20 and the locking state between the flange portion 26 and the locking portion 27. It is suppressed to be pulled out.
  • the solder of the locking portion 27 is formed all around the wire 25 , the flange portion 26 does not crush only a portion of the wire 25 . Therefore, since the electric wire 25 is not damaged, the withstand voltage of the cable 20 is prevented from being lowered.
  • the locking portion 27 is provided at the tip of the ferrule 22 of the cable 20 so as to surround the electric wire 25 . Accordingly, in the load cell 1, even when the cable 20 is pulled from the strain body 10, the locking portion 27 is always locked to the flange portion 26 of the ferrule 22, and the cable 20 is pulled from the strain body 10. It is possible to prevent it from being pulled out.
  • the load cell 1 can further improve the pull-out force for the cable 20 without lowering the withstand voltage of the cable 20 as compared with the conventional load cell.
  • the engaging portion 27 is formed by solder, but the present invention is not limited to this. Resin or adhesive may be used.
  • the load cell of the present invention has been described above with reference to preferred embodiments, the load cell of the present invention is not limited to the configuration of the above embodiments.
  • the material forming the engaging portion 27 does not have to be heat-resistant if it is used in an application that does not need to be used in a mold.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Force In General (AREA)
  • Details Of Connecting Devices For Male And Female Coupling (AREA)
PCT/JP2022/017557 2021-06-04 2022-04-12 ロードセル WO2022254971A1 (ja)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021-094636 2021-06-04
JP2021094636A JP7506029B2 (ja) 2021-06-04 2021-06-04 ロードセル

Publications (1)

Publication Number Publication Date
WO2022254971A1 true WO2022254971A1 (ja) 2022-12-08

Family

ID=84323177

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/017557 WO2022254971A1 (ja) 2021-06-04 2022-04-12 ロードセル

Country Status (2)

Country Link
JP (1) JP7506029B2 (enrdf_load_stackoverflow)
WO (1) WO2022254971A1 (enrdf_load_stackoverflow)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5242298U (enrdf_load_stackoverflow) * 1975-09-19 1977-03-25
JPH0742172U (ja) * 1993-12-22 1995-07-21 オリンパス光学工業株式会社 コード保持構造
US5461933A (en) * 1994-02-04 1995-10-31 Acutus Industries, Inc. Shear web load cell having thermal compensation
JP2003163114A (ja) * 2001-11-26 2003-06-06 Sanyo Electric Co Ltd ソレノイド及びそれに対するリード線接続方法
JP2015076574A (ja) * 2013-10-11 2015-04-20 ティアック株式会社 ケーブル固定装置
JP2019117066A (ja) * 2017-12-26 2019-07-18 ミネベアミツミ株式会社 荷重センサおよび荷重センサ一体型多軸アクチュエータ

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5242298U (enrdf_load_stackoverflow) * 1975-09-19 1977-03-25
JPH0742172U (ja) * 1993-12-22 1995-07-21 オリンパス光学工業株式会社 コード保持構造
US5461933A (en) * 1994-02-04 1995-10-31 Acutus Industries, Inc. Shear web load cell having thermal compensation
JP2003163114A (ja) * 2001-11-26 2003-06-06 Sanyo Electric Co Ltd ソレノイド及びそれに対するリード線接続方法
JP2015076574A (ja) * 2013-10-11 2015-04-20 ティアック株式会社 ケーブル固定装置
JP2019117066A (ja) * 2017-12-26 2019-07-18 ミネベアミツミ株式会社 荷重センサおよび荷重センサ一体型多軸アクチュエータ

Also Published As

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JP2022186425A (ja) 2022-12-15
JP7506029B2 (ja) 2024-06-25

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