JP5363031B2 - Joint structure of injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint structure of an injection molding machine which includes a countermeasure against abrasion to replace the embedding of solid lubricant pellets. <P>SOLUTION: On the inner peripheral surface of a cylindrical first member 41 and the outer peripheral surface of an axial second member 42 there are formed solid lubricant-dispersed, copper-based sintered layers 45, 46 that consist of, by mass%, a 10-40% Ni component, 3-10% Sn component, 0.1-4% P component, 1-10% solid lubricant component and the remainder Cu component. Fine particles of a solid lubricant are dispersed in the solid lubricant-dispersed, copper-based sintered layers and the particles of this solid lubricant exhibit lubrication action. The solid lubricant, added in an amount as little as 1-10 mass% and dispersed in the sintered layers, is almost free of the risk that it scatters by coming off from the sintered layers. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a joint structure disposed in a drive system of an injection molding machine.

The development of injection molding machines has been remarkable, and in recent years, models capable of molding disk substrates for CDs (compact disks) have been put into practical use.
However, in the molding of the disk substrate, a high cycle molding of one cycle is performed in several seconds (4 seconds or less), and the use conditions in the joint structure arranged in the drive system of the injection molding machine become severe.

A mold clamping device is indispensable for an injection molding machine, and various forms of this mold clamping device have been put to practical use. One of them is a toggle type mold clamping device. Since the toggle type mold clamping device has a toggle link mechanism to which the principle of leverage can be applied as a main element, a large mold clamping force can be obtained with a small drive source, and it is preferably used.
The toggle type mold clamping device has a large number of joints, and in high cycle molding, a large load acts on these joints and the number of so-called joint movements increases, resulting in severe wear.

Therefore, conventionally, a structure in which solid lubricant pellets are embedded as a countermeasure against wear has been proposed (see, for example, Patent Document 1).
JP-A-62-142061 (Fig. 5)

Patent document 1 is demonstrated based on the following figure.
FIG. 7 is a diagram for explaining a basic configuration of the conventional technique. In the joint structure 100 in which the shaft-shaped second member 102 is inserted into the cylindrical first member 101, a plurality of the first member 101 has a plurality of members. Holes 103 are formed, and cylindrical solid lubricants 104 are embedded in these holes 103.
These solid lubricants 104 come into contact with the second member 102 and exert a lubricating action.
That is, since the load is borne on the inner peripheral surface of the first member 101 and the lubricating action is exhibited by the solid lubricant 104, the joint structure 100 is suitable for high cycle molding.

  However, the solid lubricant 104 is peeled off by the wear action and becomes a fine powder. Since this powder scatters around, it is necessary to take dust-proof measures, and use in a clean house is limited.

Then, the structure which replaces solid lubricant pellet embedding has been proposed (for example, refer patent document 2).
JP 2003-236653 A (FIG. 2)

Patent document 2 is demonstrated based on the following figure.
FIG. 8 is another diagram for explaining the basic configuration of the prior art. In the joint structure 110 in which the shaft-shaped second member 112 is inserted into the cylindrical first member 111, the second member 112 is shown. A diamond-like carbon film 113 is coated on the outer peripheral surface.
The diamond-like carbon film 113 is excellent in wear resistance, and there is no fear that fine powder is scattered.

However, since the diamond-like carbon film 113 is formed by the plasma method, the manufacturing cost increases. The film thickness obtained by the plasma method is limited to several μm to several tens of μm. Since the wear proceeds even if the wear resistance is excellent, the usable time is short at a film thickness of about several tens of μm, and the second member 112 needs to be frequently replaced. As a result, the operation cost increases.
Therefore, wear countermeasures are required in place of solid lubricants and diamond-like carbon films.

  An object of the present invention is to provide a joint structure of an injection molding machine in which solid lubricant pellets are embedded and wear countermeasures are taken in place of diamond-like carbon films.

The invention according to claim 1 comprises a cylindrical first member and a shaft-like second member inserted into the first member, and is a joint structure arranged in a drive system of an injection molding machine.
On the sliding surface of the first member and the sliding surface of the second member , the Ni component is 10 to 40% by mass, the Sn component is 3 to 10% by mass, the P component is 0.1 to 4% by mass, A solid lubricant-dispersed copper-based sintered layer composed of 1 to 10% by mass of a solid lubricant component in which particles of a solid lubricant are dispersed and the remaining Cu component is formed,
By contacting the these solid lubricants dispersed copper based sintered layers together, characterized in that it exhibits a lubricating action on the particles of the solid lubricant.

  In the invention which concerns on Claim 2, in addition to the said component, the sintered layer contains 50 mass% or less of Fe components, It is characterized by the above-mentioned.

  The invention according to claim 3 is characterized in that the solid lubricant-dispersed copper-based sintered layer is impregnated with a lubricating oil by a vacuum impregnation method.

  The invention according to claim 4 is characterized in that the sliding surface of the second member is provided on all or part of the outer peripheral surface of the shaft.

  The invention according to claim 5 is characterized in that the second member is provided with an oil supply passage through which lubricating oil can be supplied from the end surface of the shaft to the sliding surface.

  The invention according to claim 6 is characterized in that the first member is a bush of the link mechanism and the second member is a pin of the link mechanism.

  The invention according to claim 7 is characterized in that the solid lubricant component is graphite.

In the invention according to claim 1, the solid lubricant-dispersed copper-based sintered layer is provided on the sliding surface of the cylindrical first member and the sliding surface of the shaft-shaped second member constituting the joint portion of the injection molding machine. Formed.
Fine solid lubricant particles are dispersed in the solid lubricant-dispersed copper-based sintered layer, and the solid lubricant particles exert a lubricating action. Since the solid lubricant component is added in a small amount of 1 to 10% by mass and dispersed in the sintered layer, there is almost no fear of falling off and scattering from the sintered layer.

Further, since the thickness of the sintered layer can be freely selected, it can be set to an arbitrary thickness considering the lifetime.
Furthermore, copper has a remarkably higher thermal conductivity than iron and exerts an effect of lowering its own temperature by dissipating frictional heat. Since the copper-based sintered layer is formed on the sliding surface of the first member and the sliding surface of the second member and the thickness of the copper-based sintered layer is doubled, the ability to dissipate frictional heat is doubled. The temperature of the sliding surface can be lowered.

  The nickel (Ni) component diffuses into the copper (Cu) component, which is the main component, and contributes to the improvement of the wear resistance of the sintered alloy layer and the strength of the ground. In addition, the nickel component diffuses to the surface of the first member or the surface of the second member during sintering, and the interface is alloyed to increase the adhesion strength of the sintered alloy layer to the first member or the second member. Partly alloyed with the phosphorus (P) component to form a nickel-phosphorus alloy, and the sintered alloy layer is firmly adhered to the first member or the second member in combination with the alloying by diffusion of the nickel component at the interface. It works to unite.

  Furthermore, when the nickel component diffuses into the copper component during sintering, there is an effect of increasing the porosity by forming voids in the sintered alloy layer. If the blending amount is less than 10% by mass, the above-described effect cannot be obtained, and even if the blending amount exceeds 40% by mass, the above-mentioned effect will reach its peak. .

  Tin (Sn) component forms a bronze by alloying with the main component copper component, contributes to the improvement of the ground strength, toughness, mechanical strength and wear resistance of the sintered alloy layer, and together with the nickel component It has the effect of increasing the porosity of the sintered alloy layer. When the blending amount is less than 3% by mass, the above-described effects are not sufficiently exhibited, and when the blending amount exceeds 10% by mass, the sinterability is adversely affected. Therefore, 3-10 mass% is suitable for the compounding quantity of a tin component.

  The phosphorus (P) component is partly alloyed with the copper component as a main component and the nickel component in the component to increase the strength of the ground of the sintered alloy layer and contribute to the improvement of wear resistance. Moreover, since phosphorus itself has a strong reducing power, the surface of the first member or the surface of the second member is purified by a reducing action, and the nickel component described above diffuses to the surface of the first member or the surface of the second member. This has the effect of promoting alloying. If the blending amount is less than 0.1% by mass, the above-described effects are not sufficiently exhibited, and if it exceeds 4% by mass, the strength is adversely affected. Therefore, 0.1-4 mass% is suitable for the compounding quantity of a phosphorus component.

The solid lubricant component is principally graphite, but may be one or a mixture of MoS ₂ (molybdenum disulfide), WS ₂ , and BN. It goes without saying that the lubricity can be improved by including a solid lubricant component. However, if it is less than 1% by mass, the expected lubricity cannot be obtained. On the other hand, if it exceeds 10% by mass, problems arise in the sinterability and the adhesion to the first and second members, and the soft solid lubricant component becomes excessive, thereby reducing the mechanical strength of the sintered layer. Therefore, the solid lubricant component represented by graphite is added in the range of 1 to 10% by mass.

In the invention which concerns on Claim 2, in addition to the said component, the sintered layer contains Fe component 50 mass% or less.
The iron component does not form a solid solution with the copper component constituting the main component, but is dispersed in the alloy and has an effect of increasing the strength of the ground. In addition, when part of the copper component diffuses into the iron component during sintering, there is an effect of increasing the porosity of the sintered body.
In general, the iron component tends to alloy with the phosphorus component in the presence of the phosphorus component to precipitate a hard iron-phosphorus alloy, but in the present invention, the nickel component in the component exhibits the action of suppressing the alloying. Therefore, a relatively large amount up to 50% by mass can be blended.

  The invention according to claim 3 is characterized in that the solid lubricant-dispersed copper-based sintered layer is impregnated with a lubricating oil by a vacuum impregnation method. The impregnated lubricating oil exerts a lubricating action. Provides smooth lubrication in cooperation with solid lubricants. It is also possible to reduce the amount of solid lubricant added by the amount impregnated with the lubricating oil.

  The invention according to claim 4 is characterized in that the sliding surface of the second member is provided on all or part of the outer peripheral surface of the shaft. When the sintered layer is formed on the entire outer peripheral surface of the shaft, the sintering process is facilitated, and the manufacturing cost can be reduced. Further, when a sintered layer is formed on a part of the outer peripheral surface of the shaft, the sintering raw material can be saved and effective utilization of earth resources can be promoted.

  The invention according to claim 5 is characterized in that the second member is provided with an oil supply passage through which lubricating oil can be supplied from the end surface of the shaft to the sliding surface. Lubricating oil exerts a lubricating action on the sliding surface. Provides smooth lubrication in cooperation with solid lubricants. It is also possible to reduce the amount of solid lubricant added by the amount impregnated with the lubricating oil.

  The invention according to claim 6 is characterized in that the first member is a bush of the link mechanism and the second member is a pin of the link mechanism. In other words, by applying the present invention to a toggle type mold clamping device, it is possible to take good measures against wear on the toggle type mold clamp device, thereby extending the life of the toggle type mold clamp device and reducing the manufacturing cost. it can.

  The invention according to claim 7 is characterized in that the solid lubricant component is graphite. Graphite is preferable because it is easily available, is inexpensive, and exhibits a good lubricating action.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a side view of a toggle type mold clamping device having a joint structure according to the present invention. A toggle type mold clamp device 10 includes a fixed platen 11 and a pressure receiving plate 12 disposed to face the fixed platen 11. The tie bars 13 and 13 passed to the pressure receiving plate 12 and the fixed platen 11, the movable platen 14 that moves along the tiebars 13 and 13, and the toggle link mechanism 20 that drives the movable platen 14.

  The toggle link mechanism 20 includes first links 22 and 22 connected to the pressure receiving plate 12 via pins 21 and 21, and second links connected to the first links 22 and 22 via pins 23 and 23. 24, 24, pins 25, 25 connecting these second links 24, 24 to the movable platen 14, third links 26, 26 connected in the middle of the first links 22, 22, A cross head 29 connected to the three links 26, 26, and a screw shaft 28 screwed to a nut 27 fitted to the cross head 29.

  When the screw shaft 28 is turned, the nut 27 moves to the left in the figure, and the first link 22 and the second link 24 change from the letter I to the letter V. As a result, the movable platen 14 moves to the left in the figure. Next, when the nut 27 is moved to the right in the figure, the first link 22 and the second link 24 change from a letter V to an letter I, and the movable platen 14 moves to the right in the figure.

  At this time, the movable platen 14 is guided by the tie bars 13, 13, but it is not preferable that a bending force is applied to the tie bars 13, 13. Therefore, a structure is adopted in which a slider 30 is provided below the movable platen 14 and the slider 30 is placed on the receiving plate 31 and slid. Since the load of the movable platen 14 is supported by the receiving plate 31 via the slider 30, there is no fear that a bending force acts on the tie bars 13, 13.

  FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1, and the screw shaft 28 is driven by an electric motor 35 via a pulley 32, a belt 33, and a pulley 34. The pin 21 that connects the pressure receiving plate 12 and the first link 22 is a main part of the first joint portion 37, and the pin 23 that connects the first link 22 and the second link 24 is a main part of the second joint portion 38. The pin 25 that connects the second link 24 and the movable platen 14 becomes a main part of the third joint part 39, and the first link 22 and the second link 24 are formed by the first to third joint parts 37-39. It is possible to swing in the front and back direction of the drawing, and so-called joint movement can be performed.

The configurations of the first to third joint portions 37 to 39 are basically the same. Therefore, the details will be described with reference to the next figure, taking the third joint portion 39 as an example.
FIG. 3 is an enlarged sectional view of a part 3 in FIG. 2, and the third joint part 39 includes cylindrical first members 41 and 41 and a shaft-like second member inserted into the first members 41 and 41. 42. Specifically, the first members 41 and 41 are bushes of the toggle link mechanism, and the second member 42 is specifically a pin (FIG. 2, reference numeral 25) of the toggle link mechanism.

  The second member 42 is provided with oil supply passages 43 and 43 through which lubricating oil can be supplied from the end surface of the shaft to the sliding surface. Reference numerals 44 and 44 denote lock bolts for fixing the second member 42 to the movable platen 14.

4 is a cross-sectional view taken along line 4-4 of FIG. However, for easy understanding, the first member 41 and the second member 42 are drawn separately.
On the inner peripheral surface of the cylindrical first member 41, the Ni component is 10 to 40% by mass, the Sn component is 3 to 10% by mass, the P component is 0.1 to 4% by mass, and the solid lubricant components 1 to 10 are used. A solid lubricant-dispersed copper-based sintered layer 45 composed of mass% and the remaining Cu component is formed. Furthermore, the Fe component can be contained up to 50% by mass.
The thickness of the solid lubricant-dispersed copper-based sintered layer 45 is preferably about 1 mm.

Further, the Ni component 10 to 40% by mass, the Sn component 3 to 10% by mass, the P component 0.1 to 4% by mass and the solid lubricant component 1 to 1 are also provided on the outer peripheral surface of the shaft-shaped second member 42. A solid lubricant-dispersed copper-based sintered layer 46 composed of 10% by mass and the remaining Cu component is formed. Furthermore, the Fe component can be contained up to 50% by mass.
The thickness of the solid lubricant-dispersed copper-based sintered layer 46 is preferably about 1 mm.

The composition of the solid lubricant-dispersed copper-based sintered layers 45 and 46 was determined for the following reason.
First, the nickel (Ni) component diffuses into the copper component which is a main component, and contributes to the improvement of the wear resistance of the sintered alloy layer and the strength of the ground. In addition, the nickel component diffuses to the surface of the first member or the surface of the second member during sintering, and the interface is alloyed to increase the adhesion strength of the sintered alloy layer to the first member or the second member. Partly alloyed with the phosphorus (P) component to form a nickel-phosphorus alloy, and the sintered alloy layer is firmly adhered to the first member or the second member in combination with the alloying by diffusion of the nickel component at the interface. It works to unite.

  Furthermore, when the nickel component diffuses into the copper component during sintering, it has an effect of increasing the porosity by forming voids in the sintered alloy layer. If the blending amount is less than 10% by mass, the above-described effect cannot be obtained, and even if the blending amount exceeds 40% by mass, the above-mentioned effect will reach its peak, so that the blending amount of the nickel component is suitably 10-40% by mass. .

  Tin (Sn) component forms a bronze by alloying with the main component copper component, contributes to the improvement of the ground strength, toughness, mechanical strength and wear resistance of the sintered alloy layer, and together with the nickel component It has the effect of increasing the porosity of the sintered alloy layer. When the blending amount is less than 3% by mass, the above-described effects are not sufficiently exhibited, and when the blending amount exceeds 10% by mass, the sinterability is adversely affected. Therefore, 3-10 mass% is suitable for the compounding quantity of a tin component.

  The phosphorus (P) component is partly alloyed with the copper component as a main component and the nickel component in the component to increase the strength of the ground of the sintered alloy layer and contribute to the improvement of wear resistance. Moreover, since phosphorus itself has a strong reducing power, the surface of the first member or the surface of the second member is purified by a reducing action, and the nickel component described above diffuses to the surface of the first member or the surface of the second member. This has the effect of promoting alloying. If the blending amount is less than 0.1% by mass, the above-described effects are not sufficiently exhibited, and if it exceeds 4% by mass, the strength is adversely affected. Therefore, 0.1-4 mass% is suitable for the compounding quantity of a phosphorus component.

The solid lubricant component is principally graphite, but may be one or a mixture of MoS ₂ (molybdenum disulfide), WS ₂ , and BN. It goes without saying that the lubricity can be improved by including a solid lubricant component. However, if it is less than 1% by mass, the expected lubricity cannot be obtained. On the other hand, if it exceeds 10% by mass, problems arise in the sinterability and the adhesion to the first and second members, and the soft solid lubricant component becomes excessive, thereby reducing the mechanical strength of the sintered layer. Therefore, the solid lubricant component represented by graphite is added in the range of 1 to 10% by mass.

In addition to the above components, the sintered layer can also contain an iron (Fe) component.
The iron component does not form a solid solution with the copper component constituting the main component, but is dispersed in the alloy and has an effect of increasing the strength of the ground. In addition, when part of the copper component diffuses into the iron component during sintering, there is an effect of increasing the porosity of the sintered body.
In general, the iron component tends to alloy with phosphorus in the presence of the phosphorus component to precipitate a hard iron-phosphorus alloy, but in the present invention, the nickel component in the component exerts an action of suppressing the alloying. , Relatively large amounts up to 50% by mass can be blended.

  Next, a method for manufacturing the solid lubricant-dispersed copper-based sintered layers 45 and 46 will be described. The solid lubricant-dispersed copper-based sintered layers 45 and 46 can be applied in two types: a copper-based sintered layer containing no iron component and a copper-based sintered layer containing an iron component. For convenience, the solid lubricant-dispersed copper-based sintered layer containing no iron component is referred to as “copper A-based sintered layer”, and the solid lubricant-dispersed copper-based sintered layer containing iron component is conveniently referred to as “copper B-based sintered layer”. It will be called a “sintered layer”.

○ Manufacturing method of copper A-based sintered layer:
Cu powder, Ni powder 10 to 40% by mass, Sn powder 3 to 10% by mass, phosphorous copper alloy (including P14.5%) P component 0.1 to 4% by mass, solid lubricant powder 1-10 mass%, if necessary, a binder is added and mixed for a predetermined time with a V-type mixer to produce a mixed powder.

The obtained mixed powder is loaded into a mold and molded at a molding pressure of 2000 to 7000 kg / cm ² to produce a cylindrical molded green compact having a predetermined inner diameter, outer diameter, and length.
After the obtained green compact is fitted to the inner peripheral surface of the cylindrical first member or the outer peripheral surface of the shaft-shaped second member, it is placed in a heating furnace adjusted to a neutral or reducing atmosphere. And sinter at a temperature of 800 to 1000 ° C. for 20 to 90 minutes to obtain a copper A-based sintered layer. The copper A-based sintered layer is machined and finished to a predetermined thickness (1 mm).

  The obtained copper A-based sintered layer is preferably impregnated with a lubricating oil at a rate of 5 to 20% by volume by a vacuum impregnation method. The impregnated lubricating oil exerts a lubricating action. Provides smooth lubrication in cooperation with solid lubricants. It is also possible to reduce the amount of solid lubricant added by the amount impregnated with the lubricating oil.

○ Manufacturing method of copper B-based sintered layer:
Cu powder, Ni powder 10 to 40% by mass, Sn powder 3 to 10% by mass, phosphorous copper alloy (including P14.5%) P component 0.1 to 4% by mass, solid lubricant 1-10 mass% of powder, Fe powder of 50 mass% or less, and if necessary, a binder is added and mixed for a predetermined time with a V-type mixer to produce a mixed powder.

The obtained mixed powder is loaded into a mold and molded at a molding pressure of 2000 to 7000 kg / cm ² to produce a cylindrical molded green compact having a predetermined inner diameter, outer diameter, and length.
After the obtained green compact is fitted to the inner peripheral surface of the cylindrical first member or the outer peripheral surface of the shaft-shaped second member, it is placed in a heating furnace adjusted to a neutral or reducing atmosphere. And sintering for 20 to 90 minutes at a temperature of 800 to 1000 ° C. to obtain a copper B-based sintered layer. The copper B-based sintered layer is machined and finished to a predetermined thickness (1 mm).

  The obtained copper B-based sintered layer is preferably impregnated with a lubricating oil at a rate of 5 to 20% by volume by a vacuum impregnation method. The impregnated lubricating oil exerts a lubricating action. Provides smooth lubrication in cooperation with solid lubricants. It is also possible to reduce the amount of solid lubricant added by the amount impregnated with the lubricating oil.

  The second member 42 was combined with the first member 41 having the above configuration, and an abrasion test was performed to confirm the effect of this combination. Details of the test at that time will be explained next.

(Experimental example)
Experimental examples according to the present invention will be described below. “Experiment 1” is a wear test using an actual machine, and “Experiment 2” is a rocking wear test using a bench test, but the present invention is not limited to these experimental examples.

○ Common conditions for Experiment 1:
-Composition of solid lubricant dispersed copper A-based sintered layer (copper A-based sintered layer): shown in Table 1.
-Composition of solid lubricant dispersed copper B-based sintered layer (copper B-based sintered layer):

○ Comparative Example 1:
First member (bush): inner diameter 60 mm. Solid lubricant embedded high-strength brass. There is no sintered layer on the sliding surface.
Second member (pin): outer diameter 60 mm. SCM440 steel. Induction hardening on the surface. There is no sintered layer on the sliding surface.

○ Comparative Example 2:
-1st member (bush): Finished internal diameter 60mm. S45C steel. Solid lubricant-dispersed copper A-based sintered layer is formed on the sliding surface. The thickness of the sintered layer is 1 mm.
Second member (pin): outer diameter 60 mm. SCM440 steel. Induction hardening on the surface. There is no sintered layer on the sliding surface.

○ Comparative Example 3:
-1st member (bush): Finished internal diameter 60mm. S45C steel. Solid lubricant-dispersed copper A-based sintered layer is formed on the sliding surface. The thickness of the sintered layer is 1 mm.
-2nd member (pin): Finished outer diameter 60mm. SCM440 steel. SiC eutectoid electroless nickel plating film coating on the surface.

Example 1
-1st member (bush): Finished internal diameter 60mm. S45C steel. Solid lubricant-dispersed copper A-based sintered layer is formed on the sliding surface. The thickness of the sintered layer is 1 mm.
-2nd member (pin): Finished outer diameter 60mm. SCM440 steel. Solid lubricant-dispersed copper A-based sintered layer is formed on the sliding surface. The thickness of the sintered layer is 1 mm.

Example 2
-1st member (bush): Finished internal diameter 60mm. S45C steel. Solid lubricant-dispersed copper B-based sintered layer is formed on the sliding surface. The thickness of the sintered layer is 1 mm.
-2nd member (pin): Finished outer diameter 60mm. SCM440 steel. Solid lubricant-dispersed copper B-based sintered layer is formed on the sliding surface. The thickness of the sintered layer is 1 mm.

Example 3
-1st member (bush): Finished internal diameter 60mm. S45C steel. Solid lubricant-dispersed copper A-based sintered layer is formed on the sliding surface. The thickness of the sintered layer is 1 mm.
-2nd member (pin): Finished outer diameter 60mm. SCM440 steel. Solid lubricant-dispersed copper B-based sintered layer is formed on the sliding surface. The thickness of the sintered layer is 1 mm.

○ Wear test conditions in Experiment 1:
Test equipment used: Injection molding machine (NEX50 manufactured by Nissei Plastic Industry Co., Ltd.)
・ Number of shots: 3 million shots ・ Lubrication: 0.05 cm ³ of lubricating oil is supplied per 5000 shots.
-Number of joints to be tested: 8

  Injection molding was performed for 3 million shots, and the amount of wear in the first member and the second member was measured. The amount of wear (range) was determined from the maximum and minimum values at a plurality of joints, and the amount of wear (average value) was averaged at the plurality of joints. The measurement results are shown in the following table.

In Comparative Examples 1 to 3, the wear amount of the first member is much larger than the wear amount of the second member. This is considered because the second member is too hard. In this respect, in Examples 1 to 3, the wear amount of the second member was not significantly different from that of the comparative example, and the wear amount of the first member was small.
Rather than comparing only the first member or only the second member, the wear amount obtained by summing the wear amount (average value * 1) of the first member and the wear amount (average value * 2) of the second member The total (* 1 + * 2) was evaluated (same for Experiment 2).

FIG. 5 is a graph showing the total amount of wear in Experiment 1, and the total amount of wear is a graph of the total amount of wear of the first member and the amount of wear of the second member, that is, the bottom row of Table 2. Is.
Of Comparative Examples 1 to 3, Comparative Example 3 with the best results had a total wear amount of 97 μm.
On the other hand, in Examples 1 to 3, Example 1 that had the worst result had a total wear amount of 47 μm. Therefore, compared with Comparative Examples 1-3, the abrasion loss (total value) of Examples 1-3 was 1/2 or less.

Thus, Examples 1 to 3 in which solid lubricant dispersed copper-based sintered layers (copper A-based sintered layers or copper B-based sintered layers) were formed on the sliding surfaces of both the first member and the second member. It was confirmed that the wear resistance was sufficiently improved.
Moreover, since Example 2 which formed the copper B type | system | group sintered layer in the 1st member and formed the copper B type | system | group sintered layer also in the 2nd member was the best, the iron (Fe) component was contained. It was confirmed that the wear resistance increased.

Since the experiment 1 described above was performed with an injection molding machine including a mold clamping device having eight joints, the swing angle is small depending on the joint part. Therefore, there is a possibility that the result of Experiment 1 cannot be applied to a joint portion having a large swing angle.
Therefore, it was decided to conduct a rocking wear test in Experiment 2 with a rocking angle of 90 ° (uniform).

○ Common conditions for Experiment 2:
-Composition of solid lubricant-dispersed copper A-based sintered layer (copper A-based sintered layer): Same as Experiment 1 (see Table 1)
-Composition of solid lubricant-dispersed copper B-based sintered layer (copper B-based sintered layer): Same as Experiment 1 (see Table 1)
First member: Carbon steel pipe for general structure (JIS G 3444) or carbon steel pipe for mechanical structure (JIS G 3445) is used as a bush.
Second member: A carbon steel pipe for general structure (JIS G 3444) or a carbon steel pipe for mechanical structure (JIS G 3445) is used as a pin.

○ Comparative Example 4:
First member (bush): inner diameter 60 mm. Solid lubricant embedded high-strength brass. There is no sintered layer on the sliding surface.
Second member (pin): outer diameter 60 mm. SCM440 steel. Induction hardening on the surface. There is no sintered layer on the sliding surface.

○ Comparative Example 5:
・ First member (bush): A steel pipe is used as a bush. Solid lubricant dispersed copper A-based sintered layer (copper A-based sintered layer) is formed on the sliding surface. The thickness of the sintered layer is 1 mm. The finished inner diameter is 60mm.
Second member (pin): outer diameter 60 mm. SCM440 steel. Induction hardening on the surface. There is no sintered layer on the sliding surface.

○ Comparative Example 6:
・ First member (bush): A steel pipe is used as a bush. Solid lubricant dispersed copper A-based sintered layer (copper A-based sintered layer) is formed on the sliding surface. The thickness of the sintered layer is 1 mm. The finished inner diameter is 60mm.
-2nd member (pin): Finished outer diameter 60mm. SCM440 steel. SiC eutectoid electroless nickel plating film coating on the surface.

Example 4
・ First member (bush): A steel pipe is used as a bush. Solid lubricant dispersed copper A-based sintered layer (copper A-based sintered layer) is formed on the sliding surface. The thickness of the sintered layer is 1 mm. The finished inner diameter is 60mm.
-Second member (pin): A steel pipe is substituted for the pin. Solid lubricant dispersed copper A-based sintered layer (copper A-based sintered layer) is formed on the sliding surface. The thickness of the sintered layer is 1 mm. The finished inner diameter is 60mm.

Example 5:
・ First member (bush): A steel pipe is used as a bush. Solid lubricant dispersed copper B-based sintered layer (copper B-based sintered layer) is formed on the sliding surface. The thickness of the sintered layer is 1 mm. The finished inner diameter is 60mm.
-Second member (pin): A steel pipe is substituted for the pin. Solid lubricant dispersed copper B-based sintered layer (copper B-based sintered layer) is formed on the sliding surface. The thickness of the sintered layer is 1 mm. The finished inner diameter is 60mm.

Example 6:
・ First member (bush): A steel pipe is used as a bush. Solid lubricant dispersed copper A-based sintered layer (copper A-based sintered layer) is formed on the sliding surface. The thickness of the sintered layer is 1 mm. The finished inner diameter is 60mm.
-Second member (pin): A steel pipe is substituted for the pin. Solid lubricant dispersed copper B-based sintered layer (copper B-based sintered layer) is formed on the sliding surface. The thickness of the sintered layer is 1 mm. The finished inner diameter is 60mm.

○ Rocking wear test conditions in Experiment 2:
Tester: Journal swing tester Swing mode: First member (bush) fixed, second member (shaft) swing ・ Lubrication: Initial grease application ・ Applied surface pressure: 98 N / mm ²
・ Sliding speed: 7.8 mm / second ・ Number of swinging cycles: 5 cycles per minute ・ Swinging angle: 90 °
・ Number of test cycles: 30,000 cycles

  A repeated test of 30,000 cycles was performed to measure the wear amount of the first member and the second member. In addition, the coefficient of friction was also measured.

  The friction coefficient shown on the second line from the bottom is not significantly different between Comparative Examples 4 to 6 and Examples 4 to 6. It was confirmed that the example was not worse than the comparative example in terms of the coefficient of friction.

  For the same reason as in Experiment 1, the wear amount is evaluated by the sum (* 3 + * 4) of the wear amount (average value * 3) of the first member and the wear amount (average value * 4) of the second member.

FIG. 6 is a graph showing the total amount of wear in Experiment 2. The total amount of wear is a graph of the total amount of wear of the first member and the amount of wear of the second member, that is, the bottom row of Table 3. Is.
It was confirmed that the wear amounts of Examples 4 to 6 were smaller than those of Comparative Examples 4 to 6.

Examples 4 to 6 in which solid lubricant dispersed copper-based sintered layers (copper A-based sintered layers or copper B-based sintered layers) are formed on the sliding surfaces of both the first member and the second member are rocked. It was confirmed that the wear resistance was sufficiently increased even when the angle was 90 °.
Moreover, since Example 5 which formed the copper B type | system | group sintered layer in the 1st member and formed the copper B type | system | group sintered layer also in the 2nd member was the best, the iron (Fe) component was contained. It was confirmed that the wear resistance increased.

  The joint structure of the present invention can also be applied to a link type injection machine moving device for moving an injection machine back and forth to a mold in addition to a toggle type clamping device. Therefore, the joint part structure can be widely applied to the joint part arranged in the drive system of the injection molding machine.

  The present invention is suitable for a joint structure arranged in a drive system of an injection molding machine.

It is a side view of the toggle type mold clamping apparatus which has a joint part structure concerning the present invention. FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1. FIG. 3 is a three-part enlarged cross-sectional view of FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 6 is a graph showing the total amount of wear in Experiment 1. 6 is a graph showing the total amount of wear in Experiment 2. It is a figure explaining the basic composition of the conventional technology. It is another figure explaining the basic composition of the prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 20 ... Toggle link mechanism, 25 ... Pin, 39 ... 3rd joint part (joint part structure), 41 ... 1st member, 42 ... 2nd member, 43 ... Oil supply path, 45 ... Solid lubricant formed in 1st member Dispersed copper-based sintered layer, 46... Solid lubricant dispersed copper-based sintered layer formed on the second member.

Claims (7)

In a joint structure that is composed of a cylindrical first member and a shaft-shaped second member that is inserted into the first member, and is arranged in a drive system of an injection molding machine.
On the sliding surface of the first member and the sliding surface of the second member , the Ni component is 10 to 40% by mass, the Sn component is 3 to 10% by mass, the P component is 0.1 to 4% by mass, A solid lubricant-dispersed copper-based sintered layer composed of 1 to 10% by mass of a solid lubricant component in which particles of a solid lubricant are dispersed and the remaining Cu component is formed,
A joint structure of an injection molding machine , wherein the solid lubricant- dispersed copper-based sintered layers are brought into contact with each other to exert a lubricating action on the particles of the solid lubricant.   The joint part structure of an injection molding machine according to claim 1, wherein the sintered layer contains an Fe component in an amount of 50% by mass or less in addition to the component.   The joint part structure of an injection molding machine according to claim 1 or 2, wherein the solid lubricant-dispersed copper-based sintered layer is impregnated with lubricating oil by a vacuum impregnation method.   The joint part structure of an injection molding machine according to claim 1 or 2, wherein the sliding surface of the second member is provided on all or part of the outer peripheral surface of the shaft.   The joint of the injection molding machine according to claim 1 or 2, wherein the second member is provided with an oil supply passage through which lubricating oil can be supplied from an end surface of the shaft to the sliding surface. Part structure.   6. The joint part structure of an injection molding machine according to claim 1, wherein the first member is a bush of a link mechanism, and the second member is a pin of the link mechanism.   The joint structure of an injection molding machine according to any one of claims 1 to 6, wherein the solid lubricant component is graphite.

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