Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure detecting pin attached to a cavity of a resin injection mold to detect a pressure. 2. Description of the Related Art Heretofore, as a pressure detection pin attached to a cavity of a resin injection molding die of this kind for detecting pressure,
For example, there is Japanese Utility Model Publication No. 2-42434. The pin disclosed in this publication is a pin defect detection pin having a rod portion 6 which is inserted into an insertion hole 3 formed in a resin injection mold 1 and forms a cavity 2 formed in a mold mating surface. 4, the detection pin 4 is a main body 5 having a predetermined diameter.
And a pin body having a small-diameter rod portion 6 whose front end faces the cavity 2 and forms a part of the shape thereof, and a pin body having a flange portion 7 provided on the base side. The fitting portion 8 extends from the center toward the center of the main body 5.
In this fitting portion 8, a detecting portion 10 connected to a connection line 9 connected to a monitor circuit is attached to the inner wall surface of the fitting portion 8, and a resin is attached to the fitting portion 8. 11 and the like, the detection unit 10 is fixed to the inner wall surface of the fitting unit 8 and sealed.  However, in this conventional detection pin 4, the detection part 10 is attached to the inner wall surface of the fitting part 8 pierced in the main body part 5 so as to be attached thereto. It is fixed and hermetically sealed by the resin 11.
If 0 is misaligned with respect to the axis of the main body 5, the resin pressure cannot be detected, and the reliability may be reduced. Therefore, there is a problem that the production is troublesome. -There was a problem that required a box. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has as its object to provide a pressure detection pin that is easy to assemble, has high reliability, and has a bridge circuit integrated therein.  The present invention is configured as follows in order to solve the above technical problems . sand
In other words, the small diameter lock inserted into the insertion hole of the resin injection mold
And the tip of this small-diameter rod is inserted into the mold.
Kicking a pressure detection pin which forms part of the shape of the cavity, the pressure sensing pin has a small-diameter rod portion on the tip side of the main body portion, and having an operating portion at the base side of the main body portion . This operating part is stored in the cap holder and the book
When the body is inserted through the guide hole of the cap holder
Both are bottomed cylinders that can be attached to this cap holder
The detection member is housed in a base holder having a shape.
This detecting member is formed in a sealed cylindrical shape having a pressure receiving portion with which the operating portion contacts . And on the inner surface of the pressure receiving part,
A strain gauge constituted by a bridge circuit is attached, and this bridge circuit is connected to a monitor circuit.  As described above, the detecting member is provided between the operating portion of the pin body and the operating portion.
It is formed in a sealed cylindrical shape with a pressure receiving part
With a strain gauge attached to the inner surface of the part
Therefore, the sealing performance of the detection member is improved. Pressure detection
The output pin, including its detection member,
Since it is integrated by the cap holder,
The pressure detection pin can be handled as a single part,
The assembling work on the mold is facilitated. Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a pressure detection pin 21 attached to a resin injection mold, and FIG. This pressure detection pin (hereinafter, simply referred to as a detection pin) 21 is composed of an operating pin 22, a base holder 26, a cap holder 31, and a detection member 36 housed in the base holder 26. The operating pin 22 has a main body 23 having a predetermined diameter and a small-diameter rod portion 24 having a predetermined length formed on the distal end side of the main body portion 23. A circular trapezoidal operating portion 25 is slidably received in the cap holder 31. The base holder 26 is provided with the detecting member 3
6 is formed into a bottomed cylindrical body by a bottom portion 27 and a cylindrical edge portion 28 so that the connection line 44 can be inserted through the bottom portion 27 and the cylindrical edge portion 28. A screw portion 30 screwed to the cap holder 31 is screwed into the portion. The cap holder 31 is provided with the operating pin 2.
And a guide portion 33 having a guide hole 34 for slidably guiding the main body 23 of the operating pin 22. The lower portion of the cylindrical body 32 On the outer periphery, a screw portion 35 that is screwed with the screw portion 30 of the base holder 26 is screwed. The detecting member 36 is a strain gauge type load cell. The detecting member 36 can be accommodated in the base holder 26 as shown in FIG.
And a removable bottom plate 39 to form a sealed cylindrical body having a hollow portion 40. A pressure receiving portion 41 projects in a convex shape at the center of the upper surface of the top plate 38. A gauge 42 is attached. This strain gauge 42
Is a metal foil resistor R1, bonded to a disc-shaped resin substrate 43, for example, which can be attached to the back surface of the top plate 38 as shown in FIG.
R2, R3, R4 are configured as a bridge circuit by
You. The conductor d of the covered wire D of the connection wire 44 is connected between the metal foil resistors R1, R2, R3, R4, the strain gauge 42 is attached to the back surface of the top plate 38, and the connection wire 44 is connected to the cylindrical portion 37. The detection member 36 is formed by being pulled out to the outside while being further sealed by the seal member 45, and the bottom plate 39 is fixed. The detection member 36 thus formed is housed in the base holder 26, the connection line 44 is drawn out from the groove 29, and the main body 23 of the operating pin 22 is inserted into the guide hole 34 of the cap holder 31. Then, the operating portion 25 is housed in the cylindrical body 32 and the base holder 2
The detection pins 21 are formed by screwing the screw portions 30 and 35 of the cap holder 6 and the cap holder 31. Further, in a state where the screw portions 30 and 35 are screwed together, the operating portion 2 of the operating pin 22 is
5 is in contact with the pressure receiving portion 41 of the detection member 36,
The lower four edges of the cap holder 31 are in contact with and fixed to the upper four sides of the detection member 36. The detection pin 21 formed as described above is inserted into the insertion hole 3 of the movable mold 1A of the resin injection mold 1 composed of the movable mold 1A and the fixed mold 1B as in the conventional case. The tip of the small-diameter rod portion 24 is provided so as to constitute a part of the shape of each cavity 2 formed on the mating surface. The connection line 44 is connected to a monitor circuit (not shown). When the molten resin is injected into the cavity 2 and filled in the detection pins 21 arranged in each cavity 2 as described above, the small-diameter rod portion 24 forming a part of the shape of the cavity 2 is formed. The resin pressure acts on the tip of the actuator, and an operating force F that pushes the operating pin 22 downward acts. Since this operating force F is in contact with the convex pressure receiving portion 41 formed on the top plate 38 of the detecting member 36 accommodated in the base holder 26, the operating portion 25 on the base side of the operating pin 22 is in contact with the pressure receiving portion. The top plate 38 is pressed through the portion 41. This allows
The top plate 38 is distorted, and the distortion is sensed by the metal foil resistors R1, R2, R3, R4 formed in a lattice shape, and an electric signal is sent to a monitor circuit by a bridge circuit to measure a conversion load (pressure). The resin pressure in the cavity 2 can be detected. Therefore, if the prescribed resin pressure for the cavity 2 is set on the monitor circuit side and an external display for confirming the excess or deficiency is installed in connection with this, if the resin pressure is less than the prescribed pressure, the cavity 2 The resulting product has a high possibility of underfill failure or sink failure, and if it is excessive, it can be detected that the possibility of burr failure is large, and by adjusting the subsequent injection pressure In addition, the occurrence of defective products can be prevented. In addition, detection pin 2
Since the tip of the cavity 1 constitutes a part of the cavity 2, the cavity 2 can be attached to the cavity 2 regardless of the shape and size thereof. By providing it in an easy position, the service can be sufficiently performed. In particular, the detection pin 21 is connected to the detection member 3
6. A guide hole 3 through which an operation pin 22 composed of a bottomed cylindrical base holder 26 for accommodating the actuator 6 and a main body 23 having a small-diameter rod portion 24 at the tip and an operation portion 25 on the base side is inserted.
4 and a cap holder 31 mainly including a cylindrical edge portion 28 for accommodating the operating portion 25. The detecting member 36 has a cylindrical shape sealed by a top plate 38 having a cylindrical portion 37, a pressure receiving portion 41, and a bottom plate 39. A connection formed by attaching a strain gauge 42 having metal foil resistors R1, R2, R3, and R4 arranged in a bridge circuit on a resin substrate 43 on the inner surface of the top plate 38 and connecting to the bridge circuit on the inner surface of the top plate 38 Connect line 44 to the monitor circuit,
The detection member 36 is configured to be pressed and fixed by the base holder 26 and the cap holder 31. Therefore, this detection member 36 is formed in a closed cylindrical body,
Since the strain gauge 42 is attached, the handling as a single part is easy, the assembling work of the detecting pin 21 is easy, and the working efficiency can be improved. Therefore, the watertight effect can be enhanced. In addition, since the detection member 36 is pressed and fixed by the base holder 26 and the cap holder 31, rattling or the like is prevented, and the strain gauge 42 falls off due to vibration or the like, and the disconnection of the connection line 44 is significantly reduced. As a result, responsiveness and reliability can be improved, and the durability can be improved. According to the present invention, since the detection member is configured as described above, the detection member is formed in a closed cylindrical body and a strain gauge is attached thereto. , The work of assembling the detection pin is facilitated and the working efficiency can be improved, and the watertight effect can be enhanced due to the sealed structure. In addition, since the detection member is pressed and fixed by the base holder and the cap holder, rattling or the like is prevented, and the falling off of the strain gauge 42 due to vibration or the like and the disconnection of the connection line 44 can be significantly reduced. Responsivity and reliability can be improved, and durability can be improved.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view in which a pressure detecting pin is attached to a resin injection mold. FIG. 2 is a sectional view of a pressure detection pin. FIG. 3 is a sectional view of a detection member. FIG. 4 is a perspective view of a strain gauge. FIG. 5 is a sectional view in which a conventional detection pin is attached to a resin injection mold. [Description of Signs] 1 Resin injection molding die 2 Cavity 3 Insertion hole 21 Pressure detection pin 22 Operation pin 23 Main body 24 Small diameter rod 25 Operation part 26 Base holder 27 Bottom part 28 Cylindrical edge 31 Cap holder 32 Cylindrical body 33 Guide part 34 Guide hole 36 Detecting member 37 Cylindrical part 38 Top plate 39 Bottom plate 41 Pressure receiving part 42 Strain gauge 43 Resin substrate 44 Connection line R1, R2, R3, R4 Metal foil resistance
──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int. Cl. 7 , DB name) B29C 45/00-45/84 G01L 1/22