JPH07119104A - Electrically-insulating collar for fastening rail and injection mold therefor - Google Patents

Abstract

PURPOSE:To improve the durability of an insulating collar, by a method wherein a resinous material consisting of nylon 66 in which glass staple fibers are mingled is injection-molded with a mold having resin banks which are in such directions that the resin banks equally divide a concentric circle of the boss part of the insulating collar alternately with gates and open on the outer peripheral surface of a flange part. CONSTITUTION:When a resinous material, i.e., a resin, consisting of nylon 66 in which glass staple fibers are mingled is injected at a fixed pressure through a sprue 64, the head of resin-flow is led into the sprue 64, and sludge and the like are carried away and are pushed into a sludge well 68. After that, the resin not including the sludge is led into a runner 66 and is led into a cavity 72 through a gate 74. The flow of the resin at this time strikes against the outer peripheral surface of a column 54a where the inside of the boss part of the insulating collar is to be formed, and divides into two flow parts. They go half round the column 50a and flow together at the opposite side of the gate 74, following which the resin flows out toward a resin bank 64 and only the resin being at high temperature and not involving the sludge remains in the cavity 72. Therefore, a weld line is not produced on the surface of the insulating collar.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating collar for fastening a rail which is used when fastening a rail to a track slab or a PC sleeper, and an injection molding metal fitting used for manufacturing the insulating collar.

[0002]

2. Description of the Related Art In recent years, with the sophistication of control technology for railway trains, there has been a demand for improved rail insulation performance. That is, when the electric signals communicated between the train and the rails are complicated, the deterioration of the insulation performance of the rails causes a failure in the accurate transmission / reception of signals.

FIG. 16 is a sectional view showing an example of a rail fastening device for a track slab (direct connection type 8 general use), FIG. 17 is a plan view of an insulating collar used therein, and FIG. .

In FIG. 16, reference numeral 10 is a track slab, and this slab 10 is a PC (Prestressed concrete) plate having a length of several meters in the rail length direction, which is positioned and laid on the roadbed. An embedding plug collar 12 is embedded in advance at a predetermined position in this slab 10.

In the figure, 14 is an iron tie plate having a length of several tens of cm in the rail length direction. The tie plate 14 is positioned and placed on the slab 10 with an insulating plate 16 such as a rubber mat interposed therebetween. The tie plate 14 is fixed to the slab 10 by an anchor T bolt 18 and a nut 20.

The T bolt 18 has a T-shaped bolt head 1 at the lower end.
8a. The embedded plug collar 12 has the bolt head 18
An engaging portion 12a having a flat cross-section that is substantially D-shaped so that the bolt a passes through, and the bolt head 18a is inserted into the bolt head 18a from above and rotated by 90 °. To be engaged with.

The T-bolt 18 and the tie plate 14 are electrically insulated by an insulating collar 22. The insulating collar 22 has the shape and dimensions shown in FIGS. 17 and 18, and has a cylindrical boss portion 24 and a flange portion 26 that expands from the upper end of the boss portion 24 in the outer diameter direction. The insulating collar 22 is manufactured by injection molding a polycarbonate resin mixed with about 8% by weight of glass short fibers.

As shown in FIG. 16, an insulating plate 16 and a tie plate 14 are passed through the T-bolt 18, and an iron cover plate 28, an insulating collar 22, a washer 30,
The spring washer 32 and the washer 34 are passed through. Finally, the nut 20 is screwed and tightened. Insulation collar 2 here
The second boss portion 24 enters into the bolt holes of the cover plate 28 and the tie plate 14. In this way, an insulating collar 22 is provided between the tie plate 14 and the T-bolt 18.
Electrically isolated by.

Reference numeral 36 in FIG. 16 denotes a rail, which is mounted on the tie plate 14 via an adjustment packing 38 for adjusting the rail height and a track pad 40 made of hard rubber. The leaf spring 42 that presses the rail 36 is fixed to the tie plate 14 by a bolt 44 and a nut 46.

[0010]

2. Description of the Related Art The insulating collar 22 used in this conventional rail fastening device is made of polycarbonate containing short glass fibers, and is easily broken due to a large load, and it has been found that there is a problem in durability. .

As a result of a detailed study of the cause by the inventors, it was found that the place where cracks are particularly likely to occur is near the weld line formed during injection molding. Conventionally, a mold having one gate on the outer circumference of the flange was used, but in the case of this mold, the resin flows around the gate part in the mold during injection molding. The weld line can be formed by re-joining the resin flows when such a mold is used.

That is, since cold parts, sludge, etc. are usually collected at the beginning of the flow of resin, when the two flows gathering and colliding with each other, the beginnings of both flows are not smoothly mixed and the line (weld line) ) Remains.
In this weld line, the resin is non-uniform and impurities such as sludge are also contained, so that the mechanical strength also decreases. In addition, the short glass fibers contained in the resin appear on the surface at the weld line, and oils easily enter and deteriorate. Therefore, it is considered that the insulating collar is easily broken along the weld line.

If the insulating collar is broken in this way, rainwater, rust preventive oil, etc. will enter and the insulating property will deteriorate. Therefore, in order to prevent a signal insulation failure, the insulation collar replacement period must be set short, which causes a problem of increased maintenance costs and material costs.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an insulating collar for fastening rails which improves durability of the insulating collar and reduces track maintenance cost and material cost. This is the first purpose. A second object of the present invention is to provide an injection molding die used for manufacturing the insulating collar.

[0015]

According to the present invention, a first object of the present invention is to provide a resin-made rail fastening insulating collar having a cylindrical boss portion and a flange portion that expands from one end of the boss portion in the outer diameter direction. , The resin is nylon 6 mixed with glass short fiber
Rail fastening, which is a resin material consisting of 6 and is injection-molded by a mold provided with a resin reservoir opening on the outer peripheral surface of the flange portion in a direction in which the concentric circles of the boss portion are alternately equally divided with the gate. Achieved by insulating collars.

A second object is to mold a resin-made rail fastening insulating collar by injection molding, which has a cylindrical boss portion and a flange portion which expands from one end of the boss portion in the outer diameter direction. In the mold, a pair of mold halves having a split surface including the flange portion, a gate opening to a cavity formed between the mold halves, and an outer peripheral surface of the flange portion in a direction substantially symmetrical to the gate. It is achieved by a mold for injection molding of an insulating collar for rail fastening, which is characterized in that it has a resin pool that is opened in the.

The same purpose can be achieved by providing a plurality of gates at positions where the concentric circles of the boss portion are equally divided and providing a resin pool on the outer peripheral surface of the flange portion in the intermediate direction of the adjacent gates. Here, the gate and the resin reservoir can be formed between the split surfaces, but may be a submarine type.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing an embodiment of a mold according to the present invention, and FIG. 2 is a view of a mold half on the fixed side as seen from a split surface. 3 and 4 are explanatory views of the mold splitting after injection.

The mold 50 comprises a fixed mold half 52 and a movable mold half 54. The fixed-side mold half 52 includes a fixed-side mounting plate 56 and a fixed-side mold plate 58. The movable mold half 54 includes a stripper plate 60 and a movable support plate 62.
Consists of.

The fixed-side mold half 52 is attached to a fixed plate (fixed-side die plate) of the injection molding machine, and high temperature resin supplied from the nozzle of the injection molding machine is injected into the sprue 64. The sprue 64 hits the split surface (PL) vertically and is continuous with the runner 66 located between the split surfaces (PL).
A slug well 68 facing the sprue 64 and a sprue lock pin 70 having a tip inside the slug well 68 are attached to the movable mold half 54.

The fixed side mold plate 58 is formed with a recess 58a having a shape corresponding to the outer shape of the insulating collar 22 shown in FIGS. 17 and 18, and the movable side mold half 54 corresponds to the inner diameter of the boss portion 24. A circular column 54a is provided so as to project. These recesses 58
a corresponding to the product shape between the a and the cylinder 54a
2 is formed. Both the column 54a and the sprue lock pin 70 penetrate the stripper plate 60 and are fixed to the movable side receiving plate 62.

The fixed-side template 58 has a split surface (PL).
A gate 74 and a resin pool 76 facing the front are formed.
The gate 74 is a small-diameter hole that communicates the runner 66 with a portion of the product flange portion 26 that serves as an outer peripheral surface. It should be noted that the gate 74 is provided on the outer peripheral surface of the flange portion 26, and
It is located closer to the end surface of the flange portion 26 on the opposite side.

The resin reservoir 76 is located symmetrically to the gate 74 and communicates with the cavity 72 through a small hole having a diameter larger than that of the gate 74. An appropriate number of gas vent holes 78 are formed on the surface of the fixed-side template 58 that faces the split surface (PL). The gas vent hole 78 is a very small gap formed between the split surfaces (PL) and allows the gas in the cavity 72 to escape to the outside during injection. It should be noted that in FIG. 2, a large number of gas vent holes 78 are formed at equal intervals, so that the gas can be vented smoothly.

One of the gas vent holes 78 is a resin reservoir 76.
It is provided in. Further, the opening 80 provided in the fixed mold half 52 so as to open to the recess 58a has the same function as a gas vent hole for venting gas from the boss portion 24 side.

In this embodiment, nylon 66 containing 43% by weight of glass short fibers is used for injection molding. When this mixed resin is injected from the sprue 64 at a constant pressure, the leading portion of the resin flow enters the sprue 64 to flush sludge and the like, and push the sludge and the like into the sludge well 68.
And then the resin without sludge enters the runner 66,
The gate 74 enters the cavity 72.

At this time, the flow of the resin that has entered the cavity 72 from the gate 74 is the boss portion 2 as shown by the arrow in FIG.
The outer surface of the cylinder 54a, which is the inner surface of 4, is divided into two. The two separated resin flows half-circulate around the cylinder 54a and join together on the opposite side of the gate 74. Cavity 7
In 2, the beginning of the resin flow is cooled by the inner surface of the mold,
Since it contains sludge and the like, even if the two streams collide with each other, it is difficult to uniformly mix the two streams.

However, this colliding flow is caused by the resin pool 76.
And flows out toward the inside of the cavity 72, and only the resin having a high temperature and containing no sludge remains in the cavity 72. Therefore, no weld line is generated in the cavity 72.

After the resin is cured, the mold 50 is first shown in FIG.
The movable mold half 54 is separated from the fixed mold half 52 on the split surface (PL) as shown in FIG. The resin cured at this time is attached to the movable side 54 because it is engaged with the sprue lock pin 70. On the movable side 54, the stripper plate 60 is separated from the receiving plate 62 as shown in FIG.
Then, the cylinder 54a and the sprue lock pin 70 come off from the hardened resin, and the hardened resin comes off the mold 50. After that, the gate 74 portion is cut, the product portion 22 is separated from the runner portion 66a and the sprue portion 64a, and the resin reservoir portion 76a is further separated.

It has been found that the insulating collar 22 formed by using the mold 50 as described above can obtain about three times the durable life under the same conditions as the conventional product. The resin used here is nylon 66 containing 43% by weight of glass short fiber,
Good results were obtained even when the glass short fiber content was 33, 35, 40, or 45% by weight.

Further, other resin such as BMC (bulk molding compound) may be used in place of the nylon 66 resin. This BMC is a mixture of a low shrinkage resin (polyester resin, epoxy resin, etc.), a curing agent, a thickener, an internal release agent, a pigment, a filler, and a glass fiber chopped strand in a kneader or a continuous kneader.

FIGS. 5 and 6 are views showing an embodiment in which a plurality of gates and resin reservoirs are provided respectively, and these are the half molds on the fixed side seen from the split surface (PL) as in FIG. Is. In these embodiments, the concentric circles of the boss portion 24, that is, the gates 74 that open to the outer peripheral surface of the flange portion 26 at positions where the circle sharing the central axis with the boss portion 24 is equally divided are respectively provided.
Holds 3 and 3.

Further, two and three resin reservoirs 76 are provided so as to open to the outer peripheral surface of the flange portion in the intermediate direction of these adjacent gates 72. Further, a gas vent hole 78 is formed between each resin reservoir 76 and between the resin reservoir 76 and the gate 74. Note that, in these figures, the same reference numerals are given to the portions corresponding to those in FIG. 2, and the description thereof will not be repeated.

According to the embodiments shown in FIGS. 5 and 6, since the flow distance of the resin in the cavity is short, not only is it difficult to cool the beginning of the flow, but the number of resin pools 76 is large, so weld lines are further generated. It gets harder.

FIG. 7 is a cross-sectional view of another embodiment, and FIG. 8 is a view of the fixed-side mold half 52 seen from its split surface (PL).
The mold 50A of this embodiment has a split surface (P
L) is displaced near the middle of the thickness of the flange portion 26. Therefore, in FIGS. 7 and 8, the same parts as those in FIGS. 1 and 2 are designated by the same reference numerals and the description thereof will not be repeated.

According to the embodiment shown in FIGS. 7 and 8, the following effects can be obtained. That is, the resin that has entered the cavity 72A from the gate 74A cools on the mold surface, but since the resin pool 76A is in the middle of the thickness of the flange portion 26, the cold portion at the beginning of the resin flow is the resin pool 7A.
When it flows out to 6A, it is buried in the middle of the thickness of the flange portion 26. Therefore, a weld line is less likely to appear on the surface of the flange portion 26. Further, the glass fibers are less likely to appear on the surface, and the entry of oils is prevented.

FIG. 9 is a sectional view of another embodiment, and FIG. 10 is a view showing the fixed-side mold half seen from the split surface (PL). In the mold 50B of this embodiment, the gate 74 in the embodiment of FIGS. 1 and 2 is replaced with a submarine gate 74B. This submarine gate 74B has a fixed-side template 58.
The runner 66 is communicated with the cavity 72 through the inside.

According to this embodiment, when the fixed mold half 52 and the movable mold half 54 are separated by the split surface (PL),
The gate 74B is cut off. Because the cured resin is held on the movable side 54 by the sprue lock pin 70,
This is because the gate 74A is on the fixed side 52. Therefore, it is not necessary to cut the portion of the gate 74B from the cured resin. If the passage that connects the resin reservoir 76 and the cavity 72 is also submerged in the fixed-side mold half 52 to form a submarine structure, the resin reservoir 7 can be cut when the mold 50B is split.
6 is automatically disconnected, which is more convenient.

FIG. 11 is a sectional view showing a mold of another embodiment,
FIG. 12 is a view showing the fixed-side mold half viewed from the split surface. The mold 50C of this embodiment has one pinpoint gate 74C opened on the end surface of the boss portion 24 opposite to the flange portion 26. In addition, the resin reservoir 76C is the boss portion 24.
It communicates with the outer peripheral surface of the flange portion in a direction symmetrical to the gate 74C with respect to the central axis of the.

According to this embodiment, the resin that has entered the cavity 72 from the gate 74C is divided along the circumference of the cylinder 54a corresponding to the boss portion 24 and joins at the resin reservoir 76C side. Then, since the leading portion of the flow flows out to the resin reservoir 76C, it becomes difficult to generate a weld line as in the above-described embodiments.

The mold 50C has two split surfaces PL1.
And PL2. A runner 66C connecting the sprue 64C and the gate 74C is bent at a right angle along the split surface PL2. A sludge well 68C is formed at the end of the runner 66C on the sprue 64C side, while the runner 66C can be held on the fixed side mounting plate 56C side by a runner lock pin 70C.

Therefore, in this mold 50C, when the movable side 54 is divided by the dividing surface PL1 after the resin is hardened, the product portion is held on the movable side 54 and the resin is cut off at the gate 74C. Then, when the stripper plate 60 is separated from the movable side mounting plate 62, the column 54a comes off the boss portion, and the product comes off.

In addition, the split mold surface PL2 has a fixed mold half 52C.
If you divide the runner 66C, the runner lock pin 70
Since it is held by the fixed side mounting plate 56C at C, the runner 66C comes off from the fixed side template 58C. When the stripper plate 56E is separated from the fixed-side mounting plate 56D, the resin in the runner 66C and the sprue 64C is separated from the runner lock pin 70C and falls off.

FIG. 13 is a view showing a mold of another embodiment. The mold 50D of this embodiment is the mold 50 of FIG.
The cavity 72 in C is reversed and a pin point gate 74D is opened on the flange side. In this mold 50D, a cavity 72 is formed in the movable mold half 54D.
D and the resin reservoir 76D are provided, and the column 54a that enters the inside of the boss portion 24 is fixed.

Further, in order to extrude the product cured in the cavity 72D from the mold, the movable mold half 54D is provided with an appropriate number of ejector pins 82. In FIG. 13, the portions corresponding to those in FIG. 11 are designated by the same reference numerals, and the description thereof will not be repeated. According to this embodiment, the gate 74D
Since the resin reservoir 76D is provided in a direction symmetrical to the above, the same effects as those of the above-described respective embodiments can be obtained.

FIG. 14 is a plan view of another insulating collar 22A,
FIG. 15 is a side view of a part thereof in cross section. Each of the above-described embodiments has substantially the same shape and size as those shown in FIGS. 17 and 18, but the insulating collar 22 shown in FIGS.
In A, the flanges 26A have the same thickness, and a convex portion 27 protruding annularly in the thickness direction is formed on the peripheral edge thereof. In this case, the inner diameter of the convex portion 27 is slightly larger than the outer diameter of the washer 30 shown in FIG.

The insulating collar 22A can be injection-molded by using a mold substantially similar to the molds 50 and 50A to 50D of the respective embodiments described above. According to this insulating collar 22A,
Since the outer peripheral edge of the flange portion 26A becomes thicker, it becomes more difficult to break and durability is increased.

[0047]

According to the invention of claim 1, a nylon 66 resin mixed with short glass fibers is provided with a resin reservoir opening on the outer peripheral surface of the flange portion in a direction in which the concentric circles of the boss portion are alternately equally divided with the gate. Since it is formed by injection into a metal mold, weld lines are less likely to occur and the durability of the insulating collar is improved. As a result, the insulating collar replacement period is lengthened, and maintenance costs and material costs are reduced.

According to the second aspect of the present invention, since the resin reservoir opening on the outer peripheral surface of the flange portion is provided in the gate opening to the cavity of the mold in a substantially symmetrical direction, the flow of the resin causing the weld line can be prevented. The resin near the top flows out into this resin reservoir. Therefore, a mold used for manufacturing an insulating collar without a weld line can be obtained.

A mold in which a plurality of gates are provided at positions where the concentric circles of the boss portion are equally divided, and a plurality of resin reservoirs are provided so as to open to the outer peripheral surface of the flange portion in the intermediate direction of the adjacent gates. (Claim 3) Although the gate and the resin reservoir are usually provided between the split surfaces (claim 4), the gate may be a submarine type in which the gate is inserted into the mold (claim 5).

[Brief description of drawings]

FIG. 1 is a sectional view showing a mold according to an embodiment of the present invention.

FIG. 2 is a view showing a fixed-side mold half seen from the split surface side.

FIG. 3 is an explanatory view of the die splitting of this die.

[Fig. 4] Similarly, an explanatory view of mold division

FIG. 5 is a diagram showing another arrangement example of the gate and the resin reservoir.

FIG. 6 is a diagram showing another arrangement example of the gate and the resin reservoir.

FIG. 7 is a sectional view showing an example of another mold.

FIG. 8 is a diagram showing a fixed-side mold half viewed from the split surface side.

FIG. 9 is a sectional view showing an embodiment of another mold.

FIG. 10 is a view showing a fixed-side mold half seen from the split surface side.

FIG. 11 is a sectional view showing an example of another mold.

FIG. 12 is a view showing the fixed-side mold half viewed from the split surface side.

FIG. 13 is a sectional view showing an example of another mold.

FIG. 14 is a plan view showing another embodiment of the insulating collar.

FIG. 15 is a side view of the same, partly in section

FIG. 16 is a sectional view showing an example of a rail fastening device.

FIG. 17 is a plan view of an insulating collar used therefor.

FIG. 18 is a side view of the same, partly in section

[Explanation of symbols]

 22, 22A Insulation collar 24, 24A Boss part 26, 26A Flange part 50, 50A, 50B, 50C, 50D Mold 52, 52C Fixed side mold half 54, 54D Movable side mold half 72, 72A, 72D Cavity 74, 74A, 74B, 74C Gate 76, 76A, 76C, 76D Resin reservoir

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Sadao Abe 1-6-5 Marunouchi, Chiyoda-ku, Tokyo Within East Japan Railway Company (72) Inventor Takehiro Nakajima 3-chome Hinode-cho, Miyagino-ku, Sendai-shi, Miyagi No. 8 36 in Yamaha Tohoku Co., Ltd. (72) Inventor Kuniichiro Kama 1 Downward 1 in the letter missing in Ofunato-cho, Ofunato-shi, Iwate Yamaha Ofunato Manufacturing Co., Ltd.

Claims (5)

[Claims] 1. A resin-made rail fastening insulating collar having a cylindrical boss portion and a flange portion expanding from one end of the boss portion to the outer diameter direction, wherein the resin is nylon mixed with glass short fibers. Rail fastening characterized in that it is a resin material consisting of 66 and is injection-molded by a mold provided with a resin reservoir opening on the outer peripheral surface of the flange portion in a direction in which the concentric circles of the boss portion are alternately equally divided with the gate. Insulation color. 2. A mold for injection-molding a resin-made rail fastening insulating collar having a cylindrical boss portion and a flange portion that expands in an outer diameter direction from one end of the boss portion. Of a pair of mold halves having a split surface including a portion, a gate opening to a cavity formed between the mold halves, and a resin pool opening to the outer peripheral surface of the flange portion in a direction substantially symmetrical to the gate. An injection-molding die for an insulating collar for rail fastening, comprising: 3. A mold for injection-molding a resin-made rail fastening insulating collar having a cylindrical boss portion and a flange portion that expands in an outer diameter direction from one end of the boss portion. Of a pair of mold halves having a split surface including a portion, a plurality of gates opened in a cavity formed between the mold halves at positions where the concentric circles of the boss portion are equally divided, and adjacent gates. An injection molding mold for an insulating collar for rail fastening, comprising: a plurality of resin reservoirs that are in the middle direction and open to the outer peripheral surface of the flange portion. 4. The injection molding die for an insulating collar for rail fastening according to claim 2, wherein the gate and the resin reservoir are formed between the split surfaces. 5. The rail fastening according to claim 2 or 3, wherein the gate is a submarine-type gate that communicates with the cavity through one of the mold halves, and the resin reservoir is formed between the split surfaces. Insulation collar injection mold.