JP3305671B2 - Toggle link bearing for toggle injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toggle link bearing for a toggle type injection molding machine.

[0002]

2. Description of the Related Art Normally, a toggle bush of a toggle link bearing is used under a high surface pressure of 700 to 1000 kgf / cm.
2. The low speed is 1.7 to 3.1 m / min, and the link pin of the mating material is a hard material obtained by applying chromium plating to quenched steel, and is extremely harsh due to partial reciprocating sliding. . Early wear due to the durability of the toggle bushing is likely to occur in high cycle molding (3.5 sec / shot or less) of 3.5 inch micro floppy disks or the like. The main causes are (a) the resistance of the bushing material itself. Insufficient abrasion, (b) an increase in the number of shots in a short period of time due to high cycle molding, and the like are conceivable, but at present, sufficient measures have not yet been taken.

Conventionally, a toggle bush of a toggle link bearing of a toggle injection molding machine has been made of a relatively soft copper alloy or a composite material in which a solid lubricant such as graphite is embedded in a copper alloy. The material used is a material in which chromoly steel is plated with Cr.

[0004]

With such a material,
When hard material such as bearing steel is used for the bushing material (Shore hardness 70 or more) in order to improve the durability of the bush, the mating material is used under general grease lubrication. If the compatibility of the material and hardness of the link pin is not taken into account, the pin will be used and cannot be used.

[0005] When a hard material such as bearing steel is used for the bushing material, oil lubrication is adopted as the lubrication method. In many cases, oil scatters around the molding machine, which is good for molding precision parts and the like. Not an environment. Further, an injection molding machine used for grease lubrication using a hard material as compared with such a copper alloy bearing material has not been put to practical use.

Further, when ceramics such as hard zirconia and silicon nitride are applied to improve the durability of the bush, the compatibility with chromium plating or the like is poor.

An object of the present invention is to reduce the wear of the bush material and the link pin and improve the durability by suitably combining the material and hardness of the toggle bush and the link pin of the toggle link bearing of the toggle injection molding machine. As an issue.

[0008]

A toggle link bearing according to the present invention uses a bearing steel as a bushing material, and a link pin as a mating material is made of nitrided steel, chromoly steel or martensitic stainless steel, and has a surface hardness. The hardness of the bearing steel is 5 to 15 higher than the hardness of the bushing material.
The hardness is set to 80 ± 5 .

Another toggle link bearing according to the present invention uses ceramic as a bushing material, and uses a link pin as a mating material as soft chromoly steel as compared with ceramics.
The surface hardness is 70 to 85 in Shore hardness. Preferably, the ceramic is silicon nitride or zirconia.

[0010] The lubrication of the toggle link bearing is Mo
Grease lubrication including a solid lubricant such as S ₂ , WS ₂ or graphite is preferable.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings.

FIG. 1 is a sectional plan view of a main part of a mold clamping device of a toggle type injection molding machine.

In FIG. 1, a movable platen 3 is slidably provided by a toggle mechanism on a plurality of tie bars 2 having one ends supported by an end housing 1. The movable platen 3 is provided with a movable mold 3a.

The toggle mechanism includes a first link 5 having one end pivotally connected to the movable plate 3 via a first link pin 4, and a first link 5 on both sides of the first link 5 via a second link pin 6 and a third link pin 7.
A second link 8 pivotally attached to the other end of the link 5 and the end housing 1, and a fourth link pin 9 and a fifth link
It comprises a third link 11 pivotally attached to the middle of the second link 8 via a link pin 10 and to a crosshead (not shown).

The end-handling 1 includes a mold clamping cylinder 1
The piston rod is attached to a cross head (not shown) through the end housing 1.

The first link 5 has a first toggle bush 13 at the connection with the first link pin 4, and the second link 8 has a second toggle bush at the connection with the second link pin 6 and the third link pin 7. The fourth toggle bush 16 and the fifth toggle bush 1 are provided at the connecting portions of the bush 14, the third toggle bush 15, and the third link 11 with the fourth link pin 9 and the fifth link pin 10.
7 are incorporated.

A grease hose 18 is connected to each of the link pins 4, 6, 7.9, and 10, and the other end of each grease hose 18 is connected to a distribution valve 19 attached to the end housing 1 or the like. I have. The pre-distribution valve 19
It is connected to a greasing pump via a pipeline.

(Embodiment 1) A first embodiment of the present invention relates to a toggle link bearing composed of a toggle bush and a link pin of a toggle injection molding machine, which is provided with grease lubrication or MO.
When a hard bearing steel is used for the toggle bushing under special grease lubrication including solid lubricants such as S ₂ , WS ₂ , graphite, etc., the mating material of the link pin is nitrided steel, chromoly steel or The surface hardness of the martensitic stainless steel is set to be 5 to 15 higher in Shore hardness than the hardness of the toggle bushing material.

The reason why the hardness of the link pin is limited to 5 to 15 is that when the hardness of the link pin is equal to or less than that of the bushing material, the wear resistance is not sufficient and the hardness of the bushing material is too high. This is because the aggressiveness against the bushing material is increased, and the toughness of the bushing material is impaired, so that fatigue fracture is likely to occur. The Shore hardness of the bearing steel is desirably 80 ± 5. Thus, when the bush and the link pin are formed, good lubrication can be maintained in combination with the lubrication performance of a solid lubricant or the like.

FIG. 2 shows the results of the wear test of the bearing steel bush and the chromoly steel pin. The test conditions are as follows. Mold clamping force: 150 tons Test cycle 5 sec / shot, 1 million shots Lubrication Grease lubrication Fig. 3 shows the results of the actual durability test of toggle bushing materials.
The test conditions are as follows. (Invention material) Bearing steel / Chromoly steel carburized pin: 5 sec cycle, 50
100,000 shots, mold clamping pressure 170 ton (comparative material) Copper alloy oilless metal / hard Cr plating SCM440 pin: 5.4 sec cycle, 5 million shots, mold clamping pressure 170 ton As shown in the figure, grease lubrication or MOS ₂ , WS ₂ ,
When using bearing steel (Shore hardness 80 ± 5) for bushing under special grease lubrication including solid lubricant such as graphite,
Chromoly steel carburized pin is used as the link pin of the mating material, and the surface hardness of the bush material is made 5 to 15 higher in Shore hardness than the hardness of the bush material. The wear amount of the link pin is 1/3 compared to the conventional hard chrome plated chrome steel.
/ 2, which indicates that the durability is excellent.

(Embodiment 2) A second embodiment of the present invention relates to a toggle link bearing comprising a toggle bush and a link pin of a toggle type injection molding machine, which is provided with grease lubrication or MO.
When using silicon nitride or zirconia which is ceramics for toggle bushing under special grease lubrication including solid lubricants such as S ₂ , WS ₂ , graphite, etc. Compared to soft chromoly steel, its surface hardness was 7 in Shore hardness.
0 to 85. This is because if the hardness of the pin material is low, the wear of the pin is large, and if the hardness of the pin is increased, the toughness of the pin itself is impaired, and fatigue failure is likely to occur. Thus, when the bush and the link pin are configured, good lubrication can be maintained in combination with the lubrication performance of the solid lubricant.

FIG. 4 shows the results of a wear test of a zirconia bush and a chromoly steel pin. The test conditions are the same as in the first embodiment.

The ceramic material should be combined with the same ceramic material as a counterpart material. However, since a link pin of an injection molding machine is subjected to repeated bending stress, it cannot be used with a ceramic alone which is a hard and brittle material. In addition, a method of coating the surface with ceramics is also conceivable, but it is easy to peel off, and when peeled off, a peeling piece intervenes in the sliding part, which results in damage to the toggle bush and link pin, making it difficult to apply in practice It is.

[0024]

According to the present invention, as described above, the wear of the bush material and the link pin is reduced, and the durability is improved. Also, good lubricity can be maintained in combination with the lubrication performance of the solid lubricant.

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view of a main part of a mold clamping device of a toggle injection molding machine.

FIG. 2 is a view showing a wear test result of a bearing steel bush and a chromoly steel pin according to the first embodiment of the present invention.

FIG. 3 is a view showing the results of an actual machine durability test of the toggle bush material of the first embodiment.

FIG. 4 is a view showing a wear test result using a zirconium bush and a chromoly steel pin according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 end housing 2 tie bar 3 movable plate 3a movable die 4, 6, 7, 9, 10 link pin 5, 8, 11 link 12 mold clamping cylinder 13, 14, 15, 16, 17 toggle bush 18 grease hose 19 distribution valve

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (5)

(57) [Claims] 1. A toggle link bearing comprising a toggle bush and a link pin of a toggle injection molding machine and used under grease lubrication, wherein a bearing steel is used for a bush material, and a link pin as a mating material is nitrided steel, chromoly. Steel or martensitic stainless steel, the surface hardness of which is 5 to 15 higher in Shore hardness than the hardness of the bushing material;
A toggle link bearing for a toggle injection molding machine, wherein the Shore hardness of the steel is 80 ± 5 . 2. A toggle link bearing comprising a toggle bush and a link pin of a toggle injection molding machine and used under grease lubrication, wherein ceramic is used for the bush material and a link pin as a mating material is compared with the ceramic. Made of soft chromoly steel with a surface hardness of 7 Shore hardness
A toggle link bearing for a toggle type injection molding machine, wherein the number is 0 to 85. 3. The toggle link bearing of a toggle injection molding machine according to claim 2 , wherein said ceramic is silicon nitride or zirconia. Wherein said grease lubrication, the toggle link bearing of the toggle type injection molding machine according to any one of claims 1 to 3, characterized in that it comprises a solid lubricant. 5. The toggle link bearing according to claim 4 , wherein said solid lubricant is MoS ₂ , WS ₂ or graphite.