JP5259549B2 - Carbide member for molding and molding machine equipped with the member - Google Patents

Description

  The present invention can be used for kneading and molding of a high-abrasive kneaded material containing ceramic powder as well as rubber and plastic, and a high-abrasion-resistant molding cemented carbide member (carbide cylinder and cemented carbide screw). And an extrusion molding machine equipped with the member.

  A cylindrical cylinder, a screw that is mounted in the cylinder, pushes the kneaded material forward while kneading the molding material in the cylinder, and a kneaded material of the molding material extruded by the screw is in a predetermined shape. An extrusion molding machine having a discharging die is widely used in molding fields such as rubber (elastomer) molding and various plastic moldings.

  In recent years, it has come to be used not only as a molding machine but also as a kind of chemical reaction machine. For example, it is used for polymer blending by reactive processing and interfacial reaction for polymer alloying. Are also being used. The same applies to injection molding machines.

  In the case of an extrusion molding machine or an injection molding machine whose application has been expanded from the conventional molding application as described above, for example, in a case where a high-abrasion kneaded material containing ceramic powder is mixed with a screw and discharged or injected, usually In the extrusion molding machine and the injection molding machine, the surface of the screw and the inner wall surface of the cylinder are worn by the ceramic powder, and the screw and the cylinder must be replaced within a short period of time.

  The best way to solve these problems is to form the entire screw or cylinder with a cemented carbide sintered body. When the green compact of the alloy powder material is pre-sintered, bending is inevitably generated, and a cylinder such as a cylinder is deformed. Therefore, it is very difficult to manufacture the whole with one sintered body. .

  Therefore, as a next best technique that can solve such problems, a high-hardness coating layer made of a cemented carbide material containing tungsten carbide is formed on the surface of a screw made of hardened steel or the inner wall surface of a cylinder. A technique has been proposed (see, for example, Patent Document 1).

JP 2008-132752 A

  However, even if a high-hardness coating layer as described above is formed, it merely sprays molten droplets of cemented carbide material containing tungsten carbide, so the layer deposited with the droplets deposited is deposited. It becomes only a low-density layer with a large amount of air bubbles between objects. For this reason, the durability as expected is not obtained, and when the extrusion molding machine or injection molding machine subjected to such thermal spraying treatment is used continuously for a long time, the surface of the thermal spraying screw or the inner wall surface of the thermal spraying cylinder is immediately The actual situation was that it was worn out.

  Therefore, the main problem of the present invention is to make it possible to greatly improve the wear resistance and to make the entire screw and cylinder, which are molding members, made of carbide so that they can be used continuously for a long time. Therefore, a secondary problem is to make the molding machine compatible with a highly abraded kneaded material.

The invention described in claim 1
Cylindrical superhard sintered split body 12A, 12B, 12C ..., or, the outer circumferential spiral blade portion 14b is formed, a state in which between the adjacent spiral blade portion 14b are continuous cylindrical superhard sintered split body 14A, 14B... Are cemented carbide members that are joined and integrated in the axial direction by a plurality,
In the cemented carbide sintered body 12A, 12B, 12C ... or 14A, 14B ... in the joining surface 23, the joining projection 24 protruding from the joining surface 23 of one cemented carbide sintered body is the other cemented carbide firing. It is characterized in that the joint surfaces 23 are sintered and integrated with each other while being pressed in the axial direction after being fitted in a joint recess 26 provided in the joint surface 23 of the bonded divided body in a gap fitting state .

The invention according to claim 2 is a molding machine 10 equipped with the molding cemented carbide member according to claim 1,
A cemented carbide cylinder 12 and a cemented carbide screw 14 that is mounted in the cemented carbide cylinder 12 and pushes forward while kneading the molding material in the cemented carbide cylinder 12 or injects the kneaded molding material forward. A molding machine 10 having
The cemented carbide member according to claim 1 is characterized in that the cemented carbide cylinder 12 and the cemented carbide screw 14 are formed.

  In these inventions, the entire cemented carbide cylinder 12 and the cemented carbide screw 14 as the molding members are integrally joined products of the cemented carbide sintered bodies 12A, 12B, 12C... Or 14A, 14B. Compared to the thermal spray coating layer, the entire surface, including the surface, is dense and high in strength, and can greatly improve the wear resistance of the molding member, and it can be used for high wear kneading applications that include ceramic powder. Continuous use over time is possible. Moreover, since these molding members are integrally connected in the axial direction of the cemented carbide divided bodies 12A, 12B, 12C... Or 14A, 14B... It can be produced without any occurrence. Further, each cemented carbide divided body 12A, 12B, 12C... Or 14A, 14B... Has a bonding projection 24 projecting from one bonding surface 23 on the bonding surface 23, and the bonding surface of the other divided body. 23, since it is fitted in the joint recess 26 formed in the recess 23, not only the coaxial assembly is facilitated, but also the joint area of the joint surface 23 can be increased and the strength of the joint portion is not joined. The strength of the portion can be made almost the same, and the concern that the strength of the joint portion is insufficient can be solved.

  As a result, the wear resistance of the molding member that is the cemented carbide screw or the cemented carbide cylinder of the present invention can be greatly improved, and it can be used continuously for a long time even for high wear kneading applications. As a result, the performance of the molding machine was greatly improved.

It is a partial notch front view which shows typically the extrusion molding machine of one Example of this invention. It is explanatory drawing which shows an example of the manufacturing process of a carbide cylinder. It is explanatory drawing which shows an example of the manufacturing process of a carbide screw.

  The present invention will be described in detail below with reference to the drawings. FIG. 1 is a partially cutaway front view schematically showing an extruder 10 according to an embodiment of the present invention. As shown in this figure, the extruder 10 of the present embodiment is roughly a screw type extruder (single screw extruder) composed of a carbide cylinder 12, a carbide screw 14, a heater 16, a hopper 18 and a drive device 20. Machine). The injection molding machine has almost the same structure as the screw type extruder, and is not shown in order to avoid complication. Most of the description of the extrusion molding machine 10 is used for the injection molding machine.

  The cemented carbide cylinder 12 is a cylindrical member in which the cemented carbide screw 14 is accommodated. As will be described later, this cemented carbide cylinder 12 is a molded cemented carbide member that is connected and integrated in the axial direction of a cemented carbide metal powder sintered body (that is, cemented carbide divided bodies 12A, 12B, 12C...). ) And is formed on one end side (upstream end side) in the axial direction such as a high-abrasion kneaded material such as a kneaded material containing rubber, plastic or other ceramic powder in the inside of the carbide cylinder 12. A material input port 12a for supplying material is provided, and a die (not shown) is attached to the other axial end (downstream end), and a molding material melted and kneaded in the cemented carbide cylinder 12 is provided. A material discharge port 12b for discharging toward the die is provided. The die is a die (die) that is formed by discharging the molding material discharged from the material discharge port 12b into a predetermined shape. In the case of an injection molding machine, an injection nozzle is provided instead of a die.

  The carbide cylinder 12 is wound with a heater 16 such as a band heater or a sheathed wire cast aluminum heater so as to surround the outer periphery, and the carbide cylinder 12 is heated by the heater 16. It has become. In addition, the code | symbol 22 in FIG. 1 is a blower for cooling the carbide cylinder 12 heated with this heater 16 after an operation.

  As shown in FIG. 2 (b), the cemented carbide cylinder 12 is composed of a plurality of cemented carbide sintered bodies 12A, 12B, 12C... (Connected numbers are connected as necessary). In view of this, “…” is used after the symbol to indicate that the cemented carbide sintered body may be further connected, so FIG. (This point is common throughout this specification.) As described above, and is manufactured by joining and integrating each other in the axial direction.

  Specifically, the cemented carbide material powder is compressed using an appropriate mold to form a block-shaped, for example, cubic or cylindrical green compact corresponding to the cemented carbide sintered bodies 12A, 12B, 12C. After being manufactured and pre-sintered, this pre-sintered body is molded to manufacture cemented carbide sintered bodies 12A, 12B, 12C. In this case, it is important that the fitting between the joining protrusion 24 and the joining recess 26 is appropriate so that the joining surfaces 23 are reliably joined in the main sintering.

Then, these are assembled in series in the axial direction, put in a heating furnace (not shown), and joined and integrated while being pressurized in the axial direction to obtain a rough shape of the long carbide cylinder 12. Subsequently, hot isostatic pressing “abbreviated as HIP; high temperature [maximum temperature: 1500 ° C.] and high pressure [maximum pressure: 1500 kgf / cm ² ] as a medium isotropically compressed as required. Technology to make the sintered product even more compacted and compacted to further improve the surface roughness by densifying the structure, mechanical properties and surface hardness, and eliminating residual pores in the sintered product. Alternatively, the carbide cylinder 12 is completed by diamond-polishing the inner and outer surfaces (especially the inner surface) of the rough-shaped product obtained without HIP treatment.

  Here, as the cemented carbide material for producing the cemented carbide divided bodies 12A, 12B, 12C..., For example, a material in which the main component is WC (tungsten carbide) and Co is used for the binder phase is used. Note that a part or all of the binder phase may be replaced with Ni for the purpose of improving the corrosion resistance, oxidation resistance or magnetic properties of the cemented carbide material. Further, at least one selected from carbides, nitrides, carbonitrides, borides, and the like of Ti, Ta, V, Cr, Nb, and Mo can be added as additives depending on the purpose of use. Further, when it is desired to suppress the mass of the cemented carbide material, the main component is Ti carbide, nitride or carbonitride, and the binder phase and (if necessary) the additive are added to the cermet. May be used.

  Also, the conditions (specifically, conditions such as the particle size of the metal powder, the applied pressure used for compression, the sintering temperature, and the sintering time) when manufacturing the cemented carbide divided bodies 12A, 12B, 12C ... The known conditions can be appropriately selected depending on the cemented carbide material to be used.

  The cemented carbide cylinder 12 of the present invention has a shape in which the inner circumferential circle of the transverse section with which the cemented carbide screw 14 is in sliding contact is a perfect circle and the inner surface of the longitudinal section is straight in the longitudinal direction. Although this is related to the surface wear resistance, it is necessary that the joint strength at the joint part be comparable to that of the non-joint part, and that it should have uniform strength and wear resistance as a whole. In the invention, when the cemented carbide sintered bodies 12A, 12B, 12C,... Are manufactured, as shown in FIG. 2 (a), the cemented carbide sintered bodies 12A, 12B, 12C,. Is formed with a reduced diameter outer diameter, and the inner diameter of the cemented carbide divided bodies 12A, 12B, 12C... It is preferable to provide a joint recess 26 to be engaged. Although not shown, of course, the joining surface 23 may be formed into a tapered shape with a small insertion depth and depth or other fitting shape instead of the joining protrusion 24 and the joining recess 26.

  And in joining at any joining surface 23 between the cemented carbide sintered bodies, the entire joining surface 23 is sintered by pressing in the axial direction.

  As shown in FIG. 2, by setting the joint protrusion 24 and the joint recess 26 to a slight gap fit state on the joint surface 23 (of course, the present invention is not limited to this and may be a taper-like or other fit). In addition to being able to easily assemble the bodies 12A, 12B, 12C... Into the shape of the carbide cylinder 12 while aligning the shaft in series in the axial direction, the cemented carbide sintered body 12A assembled into the shape of the carbide cylinder. 12B, 12C... Can be increased in bonding area, and the bonding strength at the bonding surface 23 can be improved. This point is basically applicable to the carbide screw 14 described below.

  The cemented carbide screw 14 is a member which is accommodated in the cemented carbide cylinder 12 and is pushed out from the material charging port 12a toward the material discharge port 12b while kneading the molding material charged into the cemented carbide cylinder 12, as shown in FIG. As shown to b), it is comprised roughly by the elongate shaft part 14a and the spiral blade | wing part 14b provided in the outer periphery in the spiral form.

  As shown in FIG. 3, the cemented carbide screw 14 has a plurality of cemented carbide divided bodies 14 </ b> A, 14 </ b> B made of a metal powder of cemented carbide material in the axial direction. Are joined and integrated while being pressurized in series and in the axial direction.

Specifically, like the cemented carbide cylinder 12, the cemented carbide material powder is compressed by using an appropriate mold, and a block shape, for example, a cubic shape, in which the entire cemented carbide sintered body is contained. Alternatively, a green compact having a cylindrical shape (or a cemented carbide divided body having spiral blades 14b projecting on the outer periphery and having a margin such as pre-sintering thinning or forming processing allowance) is manufactured. After pre-sintering this, this pre-sintered body is molded into a rough shape that allows for a post-sintering thinning and processing allowance to produce cemented carbide sintered bodies 14A, 14B. The process up to and including the diamond polishing step is the same as that of the cemented carbide cylinder 12. The material used is the same as that of the cemented carbide cylinder 12.

  Here, for the same reason as the cemented carbide cylinder 12, the cemented carbide sintered bodies 14A, 14B... Are joined to the cemented carbide sintered portion on one end side in the axial direction as shown in FIG. A fitting projection 28 that protrudes in the axial direction of the divided bodies 14A, 14B... And a fitting projection that fits the joining projection 28 of the cemented carbide sintered divided bodies 14A, 14B. It is preferable to provide a joint hole 30. The fitting of the joint protrusion 28 and the fitting hole 30 is the same as that of the cemented carbide cylinder 12. In addition to being able to easily assemble the cemented carbide divided bodies 14A, 14B... Into the shape of the cemented carbide screw 14 by providing such a joining projection 28 and the fitting hole 30, the screw shape. This is because the bonding area between the cemented carbide sintered bodies 14A, 14B... Assembled can be increased, and the bonding strength can be improved. In addition, the shape of the joint protrusion 28 and the fitting hole 30 into which the joint protrusion 28 is fitted can easily assemble the cemented carbide divided bodies 14A, 14B... Without misalignment. As long as it is possible to improve the shape, any shape may be used, for example, a conical or frustoconical groove shape, an uneven groove shape, or a dovetail shape.

  The hopper 18 is a funnel-type container for stocking the molding material and supplying the stocked molding material to the material inlet 12a of the carbide cylinder 12 stably. Various forms such as a hopper with a feeder, a vacuum hopper, and a nitrogen substitution hopper can be adopted.

  The drive device 20 is a power device for driving the carbide screw 14 to rotate, and includes a speed reducer 20 a and a motor 20 b connected to the base of the carbide screw 14.

  The extrusion molding machine 10 is completed by assembling the members described above and performing predetermined wiring and the like.

  According to the extrusion molding machine 10 of the present embodiment, the cemented carbide cylinder 12 and the cemented carbide screw 14 are configured by using a sintered body of a metal powder of cemented carbide material, so that the surfaces of these members are cemented with carbide. A dense surface can be formed as compared with the case where a high hardness coating layer is formed by thermal spraying of an alloy material. As a result, compared to the case where a high hardness coating layer is formed on the surface of the cemented carbide screw 14 or the inner wall surface of the cemented carbide cylinder 12 by thermal spraying, the wear resistance of the surface of these members can be greatly improved, and it takes a long time. Continuous use is possible. Here, at least the inner wall surface of the cemented carbide cylinder 12 and the surface of the cemented carbide screw 14 may be formed of a sintered body of a metal powder of a cemented carbide material, but considering the actual manufacturing process as described above, It is preferable that the whole of the hard cylinder 12 and the carbide screw 14 be formed of the sintered body.

  In the illustrated embodiment, a no-vent type single screw extruder has been described as an example of the extrusion machine 10, but the shape of the extrusion machine is not limited to this, and a vent type single screw extruder is used. It may be a biaxial carbide screw extruder in which two carbide screws are housed in a carbide cylinder. The difference between the extruder and the injection molding machine is basically the same except that the movements of the molding die, the injection nozzle, and the screw are different. Therefore, the above description also applies to the injection molding machine.

DESCRIPTION OF SYMBOLS 10 ... Extruder 12 ... Carbide cylinder 12A, 12B, 12C ... Carbide sintered division 14 ... Carbide screw 14A, 14B ... Carbide sintered division 16 ... Heater 18 ... Hopper 20 ... Drive device 20a ... Deceleration Machine 20b ... Motor 22 ... Blower 23 ... Joining surface 24 ... Joining projection 26 ... Joining recess 28 ... Joining projection 30 ... Fitting hole

Claims (2)

Cylindrical superhard sintered divided body, or spiral blade portion is formed on the outer periphery, adjacent cylindrical superhard sintered divided body spiral blade portions becomes a state of continuous, axially at multiple It is a cemented carbide member that is integrally joined ,
In the joining surface of the cemented carbide sintered body, the joining protrusion protruding from the joining surface of one cemented carbide sintered body is recessed in the joining surface of the other cemented carbide dividing body. A cemented carbide member formed by being joined to each other in a gap-fitted state and then being sintered and integrated while being pressed in the axial direction . A molding machine having a cemented carbide cylinder and a cemented carbide screw that is mounted in the cemented carbide cylinder and that pushes forward while kneading the molding material in the cemented carbide cylinder or injects the kneaded molding material forward. There,
The molding machine according to claim 1, wherein the cemented carbide cylinder and the cemented carbide screw are the cemented carbide member according to claim 1.

Images