JP2850730B2 - Toggle type mold clamping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device for clamping a mold such as an injection molding machine, and more particularly to a toggle mold clamping device using a toggle mechanism as a mold clamping mechanism. .

[0002]

2. Description of the Related Art As a mold clamping device used in an injection molding machine, a die casting machine, or the like, a toggle mechanism comprising a pair of link members which are relatively rotatably connected, and a mold for expanding and contracting the toggle mechanism. There is known a so-called toggle type mold clamping device having a clamping cylinder. In this toggle-type mold clamping device, a pin and a bush as a flat bearing are usually used in the connecting portion of the link member. The pin is made of a material such as chromium molybdenum steel (SCM) or aluminum chromium molybdenum steel (SACM) among carbon steel and alloy steel for machine structure, and is subjected to surface treatment such as high frequency, carburizing, and nitriding. A material having an increased surface hardness has been used, and a material made of a high-strength brass-based alloy having a lower hardness than a pin has been used as a bush. That is, in the toggle-type mold clamping device, by using a pin having a high hardness for the bush, wear caused by friction between the two can be relatively easily replaced.
In addition, a relatively inexpensive bush was used to replace the bush.

[0003]

Since the bush is required to be used for as long as possible, the length of the bush is changed by changing the type of lubricant, the supply cycle of the lubricant, the bearing surface pressure, and the like. Although the service life was extended, even if the type of lubricant, lubricant supply cycle, and bearing surface pressure were changed in this way, the service life could only be slightly extended, and a longer service life of the bush was required. It was the current situation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a toggle type mold clamp capable of extending the life of a connecting portion of a link member including a pin and a bush and reducing maintenance work of a toggle mechanism. It is intended to provide a device.

[0005]

A toggle-type mold clamping device according to the present invention includes a toggle mechanism including a link member rotatably connected to each other, and a mold-clamp cylinder that expands and contracts the toggle mechanism. A toggle-type mold clamping device for clamping a movable mold mounted on a movable plate connected to one end of the toggle mechanism, by closely contacting the fixed mold fixed to the fixed plate provided opposite to the movable mold. In the toggle mechanism,
The link member is connected by a connecting portion including a pin and a bush, and the pin and the bush are each formed of a hard steel material whose surface hardness is increased by nitriding, and the bush is provided at a plurality of positions in a circumferential direction. The solid lubricant is embedded in the radial direction.

[0006]

According to the toggle-type mold clamping device of the present invention, when the mold clamping operation is performed, the solid lubricant embedded in the bush spreads little by little on the sliding surface between the bush and the pin. A coating of the agent is formed, the coefficient of friction between the bush and the pin is reduced, and a smooth sliding state is obtained. That is, the pin and the bush are each formed of a hard steel material whose surface hardness has been increased by nitriding, and the solid lubricant embedded in the bush reduces the friction coefficient of the sliding surface to ensure a smooth sliding state. Is obtained, the wear resistance of the bush and the pin is improved, and the life of the connecting portion of the link member including the bush and the pin is extended.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a toggle-type mold clamping device according to the present invention will be described below with reference to the drawings. First, the structure of the toggle-type mold clamping device will be described with reference to FIGS. 1 and 2 as an example.

In FIG. 1, reference numeral 1 denotes an end plate, and the end plate 1 is fixed to a fixed plate 3 via a tie bar 2. A movable plate 5 located between the end plate 1 and the fixed plate 3 via a toggle mechanism 4 is attached. The tie bars 2, 2,... As a result, the movable platen 5 is slidable in the direction of arrow A in FIG.

Further, each of the fixed platen 3 and the movable platen 5 is provided with a fixed die 3a and a movable die 5a opposed thereto. Here, the toggle mechanism 4
Are mounting portions 6 provided on the upper and lower portions of the end plate 1,
6, first link members 9 and 9 rotatably connected to each other via a connecting portion P including a pin 7 and a bush 8 as a flat bearing; the first link members 9 and 9 and the movable platen 5; 2nd link members 11 and 11 rotatably connected to mounting portions 10 and 10 provided at the upper and lower portions of the vehicle through connecting portions P each including a pin 7 and a bush 8 as a flat bearing. A third link member 14 rotatably connected to branch portions 9a, 9a formed in the first link members 9, 9 via a connecting portion P including a pin 12 and a bush 13 as a flat bearing; 14, a pin 12 and a bush 1 as a plain bearing between the third link members 14, 14.
And a crosshead 15 rotatably connected via a connecting portion P made up of three.

Here, the pins 7 and 12 and the bushes 8 and 13 constituting the connecting portion P are made of chromium molybdenum steel (SCM430, SCM440, etc.) aluminum or carbon steel or carbon steel for mechanical structure. It is formed of a hard steel material such as a chromium molybdenum steel material (such as SACM645), and its surface is hardened by performing a nitriding treatment.

As shown in FIGS. 3 and 4, the bushings 8, 13 are formed with a plurality of holes 21, 21... Penetrating radially in the circumferential and longitudinal directions. The solid lubricants 22, 22,... Are fitted into the holes 21, 21,.
13 is exposed and embedded in the circumferential surface. As the solid lubricants 22, for example, graphite, dihydrated molybdenum, metallic soap and the like can be used. A mold clamping cylinder 16 is mounted on a surface of the end plate 1 opposite to the toggle mechanism 4.
The sixth piston rod 16a extends toward the fixed platen 3 through the end plate 1 and is fixed to the crosshead 15.

According to the toggle-type mold clamping device having the above-described structure, the crosshead 15 is moved in the direction of arrow A in FIG. With the movement of the first link member 14, the connecting portion between the first link member 9, 9 and the second link member 11, 11 connected to the crosshead 15 by the third link member 14, 14 is expanded in the direction away from each other. Then, the first link members 9, 9 and the second
The movable platen 5 is moved in the direction of the fixed platen 3 by the separation of the connecting portion between the link members 11, 11, and the movable die 5 a is brought into close contact with the fixed die 3 a and clamped by the movable platen 5 and the fixed platen 3. .

Here, as described above, the mold clamping cylinder 16
When the mold is clamped by extending the piston rod 16a of the solid lubricant 2 embedded in the bushes 8, 13,
2, 22,... Gradually spread on the sliding surface with the pins 7, 12, and a lubricant film is formed on the sliding surface (a hard carbon film is formed when graphite is used as a solid lubricant). ), The friction coefficient between the bushes 8, 13 and the pins 7, 12 is reduced, and the bushes 8, 13 and the pins 7, 1
2 can be very smoothly slid.

That is, according to the toggle-type mold clamping device of the present embodiment, carbon steel for machine structure, chromium molybdenum steel, Alternatively, a hard steel material made of aluminum chromium molybdenum steel or the like is used, and the surface thereof is hardened by nitriding treatment, and solid lubricants 22, 22,. Since the friction coefficient is reduced to obtain a smooth sliding state, the wear resistance of the pins 7, 12 and the bushes 8, 13 can be significantly improved, and the pins 7, 12, and the bush 8 can be improved. , 13 can be extended.

This improves the abrasion resistance of the bushes 8, 13 which have conventionally had to be easily worn as compared with the pins 7, 12, thereby improving the replacement period of the bushes 8, 13 and the lubricant. The supply interval can be lengthened, and the number of maintenance operations can be significantly reduced.

The specific structure and structure of the toggle-type mold clamping device of the above embodiment and the toggle mechanism 4 constituting the toggle-type mold clamping device are not limited to the embodiment.

(Experimental Example) A mold clamping apparatus using each bush (sample) shown in the following Table 1 was repeatedly operated, and the wear amount of the inner peripheral surface of each bush, that is, the life was compared.
As shown in FIG. 5, the bush A (this embodiment) and the bush B (conventional example) have an increased dimension Δ of the inner diameter D.
d was measured, and this Δd was taken as the amount of wear.

[0018]

[Table 1]

Next, the results of the above experiment are shown in Table 2 and FIG.

[0020]

[Table 2]

As is clear from Table 2 and FIG. 6, the bush A (this embodiment) has an extremely small amount of wear Δd as compared with the bush B (conventional example). It was confirmed that the life of the bush A was extremely long and the durability was excellent. That is, by using the bush A (the present embodiment) for the mold clamping device, as described above, the period for replacing the bush and the supply interval of the lubricant can be lengthened, and the number of maintenance operations can be greatly reduced. Can be done.

[0022]

As described above, according to the toggle-type mold clamping device of the present invention, the following effects can be obtained.
As the material of the pins constituting the connecting portion of the link member and the bush as a flat bearing, a hard steel material whose surface hardness is increased by nitriding treatment is used, and a solid lubricant is embedded in the bush to make sliding surfaces of each other. The frictional coefficient of the pin and the bush is reduced so that the wear resistance of the pin and the bush can be greatly improved. Life can be extended. This improves the abrasion resistance of the bush, which had to be easily worn as compared with the conventional pin, and can extend the replacement period of the bush and the lubricant supply interval. The number of times can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of a toggle-type mold clamping device illustrating a configuration and a structure of a toggle-type mold clamping device having a toggle mechanism.

FIG. 2 is a side cross-sectional view of the toggle-type mold clamping device illustrating a configuration and a structure of the toggle-type mold clamping device having a toggle mechanism.

FIG. 3 is a cross-sectional view of a bush illustrating a structure of a bush used for a connecting portion of a link member according to the embodiment.

FIG. 4 is a plan view of a bush illustrating a structure of a bush used for a connecting portion of a link member according to the embodiment.

FIG. 5 is a front view of the bush for explaining an experiment of wear resistance between the bush of the present embodiment and the bush of the conventional example.

FIG. 6 is a graph showing experimental results of wear resistance of the bush of the present embodiment and the bush of the conventional example.

[Explanation of symbols]

 Reference Signs List 4 toggle mechanism 5a movable type 6a fixed type 7, 12 pin 8, 13 bush 9, 11, 14 link member 16 mold cylinder 22 solid lubricant P connecting part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B29C 45/64-45 / 68,45 / 83,33 / 20-33/24 B22D 17/26 C23C 8 / 06

Claims (1)

(57) [Claims] 1. A toggle mechanism comprising a link member rotatably connected to a movable plate connected to one end of the toggle mechanism and a mold clamping cylinder for expanding and contracting the toggle mechanism. In the toggle-type mold-clamping device, which is provided so as to face the movable mold and is fixed to a fixed mold fixed to a fixed plate, the toggle-type mold-clamping device, wherein the toggle mechanism comprises a link member comprising a pin and a bush. The pin and the bush are formed of a hard steel material whose surface hardness is increased by nitriding treatment, and the bush is solid-lubricated at a plurality of positions in a circumferential direction in a radial direction. A toggle-type mold clamping device, wherein an agent is embedded.