JPH0221930B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hose used for pumping solid materials such as powders and granules, or mixtures of solid materials such as powders and granules, or mixtures of these materials dispersed in liquid. The inner layer of the sintered wear-resistant material, which is formed in a loosely fitted sintered material cylindrical unit made of sintered ceramics or sintered carbide alloy, is fixed in an even position on the inner surface of the hose that comes into contact with the hose, thereby ensuring an evenly loosely fitted state. The present invention relates to a method of manufacturing a hose in which an inner layer of a sintered wear-resistant material is held by a flexible elastomer to provide smooth flexibility to a sintered cylindrical unit.

[Conventional technology]

Conventional hoses have spherical or plate-shaped particles of sintered material such as ceramics embedded in the surface of a rubber-like elastic body to form a flexible wear-resistant surface on the inner surface of the hose that comes into contact with the pumping body. It was the main subject.
For example, in Utility Model Application Publication No. 58-142474 (name: wear-resistant rubber hose), as a claim for registration of a utility model, it is stated that "granular bodies 3 made of wear-resistant material are buried in the surface layer of the inner circumferential surface 2. A wear-resistant rubber hose is disclosed.

Furthermore, JP-A-55-129433 states that ``Particles of hard sintered metal or sintered porcelain with an average particle size of 0.05 to 10 mm and a Mohs hardness of 7 (Knoop hardness 820) or more meet the JIS-K6300 standard. For rubber with spring hardness A type specified in the physical test method for vulcanized rubber, 20 to 90,
A wear-resistant rubber lining material in which the above particles and rubber are bonded together by dispersing and mixing 10 to 60% by volume. "It is shown.

In addition, Japanese Utility Model Application Publication No. 60-31574 states, ``A through hole is provided that penetrates from one side of one end of a thin, approximately rectangular ceramic tile to the other end, and a large number of the ceramic tiles are passed through a flexible wire. , a ceramic tile-lined rubber hose characterized in that it is formed into a band shape, wound spirally, and fixed to an inner rubber surface.''

As mentioned above, the inner layer of the hose is formed of a rubber sheet made of a rubber material mixed with particles, or
With equal spacing between ceramic tiles,
Since the rubber material is connected like a string, wrapped around a core mold, covered with a rubber material, and buried, it can be molded using a conventional mandrel. Therefore, no special manufacturing method is required.

[Problem that the invention seeks to solve]

In conventional technology, where the inner surface of the hose is formed by embedding a non-stretchable wear-resistant material such as ceramics into the surface of a rubber-like elastic body, the difference in attributes between the wear-resistant material and the rubber-like elastic body is extremely large. The effect of the complex cannot be expected.

In general, fluids that require wear-resistant material on the inner surface of the hose are those used in applications where solid materials such as granules and powder or mixtures dispersed in liquid are pumped, and are generally at high temperatures. Compared to sintered materials that are wear-resistant materials such as ceramics, the heat resistance of rubber-like elastic bodies is extremely low, and the decline in physical properties and durability due to temperature is significant.
Peeling and detachment of wear-resistant materials, damage to rubber-like substances, etc. are significantly accelerated. In addition, even when used at room temperature, the differences in the attributes of the two are too large, so exposing both on the inside of the same hose will further accelerate damage to weak parts, making it impossible to fully demonstrate the characteristics of the wear-resistant material. . This is due to the wear condition of the rubber-like elastic body that holds the wear-resistant material and its holding power, but this difference in attributes leaves no room for improvement. In addition, in order to prevent the wear-resistant material from falling off, a method in which plate-like pieces are connected at intervals with flexible wire material has been devised, but this method has the potential to form a large inner surface with undesirable resistance to fluids. Although this prevents partial falling off, there is a risk that the rubber-like elastic body will wear out and the wear-resistant material will become loose, leading to a situation where the internal resistance further increases.

As mentioned above, although there are differences in the shape of the wear-resistant material, such as granular or plate-like, the concept of the conventional technology is to expose a rubber-like elastic body on the inner surface, and they can basically be considered to be of the same type. , especially when the fluid is heated, the durability is significantly reduced and it is unsuitable for use.

Therefore, the inventors were acutely aware of the need to form an inner layer of sintered wear-resistant material that does not expose the rubber-like elastic body on the inner surface of the hose, and explored a configuration that relies on an aggregate of cylindrical units made of sintered material. be. In this case, it is necessary to impart flexibility to the cylindrical unit made of a non-stretchable rigid body made of sintered material. In order to provide flexibility, the sintered cylindrical units must be shaped so that they can fit into each other, and must be connected to each other with a required amount of loose fit. Further, when fitting loosely, it is necessary to fit loosely so that the gaps between the two are approximately equal when fitted. Further, it is necessary to allow for a certain degree of error in the dimensional accuracy of the sintered material due to the sintering process. Therefore, by supporting the inner circumferential surfaces of the sintered material cylindrical units with equal internal pressure, uniform inner surfaces with no deviation are formed, and the units are loosely fitted in approximately equal positions. A flexible elastomer filled in the stepped connection part formed on the outside of the sintered material cylindrical unit maintains a loosely fitted state at almost even positions, thereby preventing the rubber-like elastic body from being exposed on the inner surface of the hose. There is a need to overcome the deficiencies of the prior art by methods of manufacturing hoses that provide suitable flexibility.

[Means for solving problems]

As described above, this invention forms an inner layer of sintered wear-resistant material on the inner surface of a hose by an aggregate of sintered material cylindrical units, but in order to obtain flexibility, the sintered material cylindrical units are In order to connect them with each other in a loose fit state, both ends of the sintered material cylindrical unit are formed into a large diameter loose fitting part and a small diameter part, and the required number of sintered material cylindrical units having this step diameter is determined. , the end of the small diameter portion is inserted into the loose fitting portion of the large diameter to form a sintered wear-resistant material inner layer in a connected state.

However, in order to provide the required flexibility, when connecting the sintered material cylindrical units to each other with the required amount of loose fitting, it is necessary to connect the sintered material cylindrical units at a position where the gap between the two when loosely fitting is approximately equal. In order to achieve such a loose fit, the sintered cylindrical units are molded on a core body that supports the inner peripheral surfaces of each other with equal internal pressure and is capable of forming an internal pressure. A means of assembly must be used.

Incidentally, the sintered material cylindrical unit is made by molding sintered material and firing it in a sintering furnace, and therefore, it is inevitable that there will be some degree of variation in its dimensional accuracy.

Therefore, when such a rigid sintered material cylindrical unit is inserted onto an iron core made of iron pikes used in conventional hose manufacturing, the gap between the small-diameter part and the iron core varies greatly, and loose fitting parts occur. It is impossible to fit the parts loosely in the same position, and irregular deformation occurs when the loosely fitting part is deflected (bended) or compressed or expanded. In addition, when open-curing in a vulcanizing can, which is a common manufacturing method for hoses, unlike inserting a rubber inner tube, it is also possible to insert the hose into the loose fit between the sintered material cylindrical units, which are rigid bodies with large variations. Steam directly enters and impedes the connection of the flexible elastomer that fills and connects the stepped joints and the integration with the reinforcing layer arranged on the upper layer.

Therefore, as a core body (mandrel) that supports the inner circumferential surfaces of the sintered cylindrical units with equal internal pressure, both ends were covered with a cylindrical elastomer sandwiched between a fixing collar and a pressing collar. Using an iron core, the sintered material cylindrical unit is placed on the mandrel in a continuous loose fit manner by inserting the end of the small diameter part into the large diameter loose fit part, and then tightening and pressing the nut. Move the brim and compress the cylindrical elastomer to expand its inner diameter. At this time, a half-split coupling for setting may be used so that the sintered material cylindrical units are installed at equal intervals. This compressed cylindrical elastomer supports the sintered material cylindrical unit with uniform internal pressure, and at the same time firmly tightens the iron core, which is the core.

Therefore, even if there is an error in the inner diameter of the sintered material cylindrical unit, or even if it is loosely fitted, the axis of the cylindrical unit will align with the core (mandrel), and it will be almost uniform. A loose fitting condition that is approximately equal to the inner circumferential surface is obtained, and the abrasion effect of the fluid exerts an even abrasion effect on the cylindrical unit, which is a wear-resistant material, thereby preventing the occurrence of local premature wear.

In particular, the feature of setting the sintered material cylindrical unit on the core body that can form internal pressure is that the step connection part formed on the outside of each unit is firmly held with a flexible elastomer, and at the same time it is held without any gaps. It is at the point where it is done.

That is, in the conventional method of directly inserting the sintered material cylindrical unit into the iron core, the cylindrical unit cannot be held firmly and also cannot be held without any gaps. The method of forming and maintaining internal pressure is particularly important when using an unvulcanized foamable elastomer as a flexible elastomer, in order to achieve uniform foaming during heating and vulcanization and simultaneous foaming during filling.

Next, if a half-split coupling for setting is used, it is removed, and a flexible elastomer material is placed in the step connection portion formed on the outside by the sintered material cylinder and the step diameter of the unit. When the flexible elastomer is a foamed elastomer,
Corresponding to the degree of foaming, an elastomer having a foaming composition having a volume that is 1/the degree of foaming is arranged and is filled and connected by foaming to the volume of the stepped connection portion.

Next, an elastomer layer is formed on the outer periphery, and a reinforcing layer such as an organic fiber cord or a steel cord layer coated with elastomer is wrapped around the outer periphery in a crosswise manner at a desired cord angle, and the outer surface is coated with elastomer. The entire body is then vulcanized and molded by applying pressure using a tightening cloth or the like.

The material used for the reinforcing layer is high strength, low elongation material such as steel cord or aromatic polyamide fiber cord (Kevlar) that shrinks due to heat, so that each sintered material cylindrical unit is set in a uniform state. A material with a small amount of The reason for this is that if a material with a large heat shrinkage is used, it will shrink in the step connection portion and the volume of this connection portion will become non-uniform. Further, in the case of low-strength, high-elongation materials, similar volume non-uniformity may occur.

In addition, instead of using the iron core coated with a cylindrical elastomer as the core capable of forming internal pressure, the same result can be obtained by using a core with an elastomer bag formed on a metal pipe that can seal in water or air pressure. Effects can be obtained. Naturally, a considerable amount of pressure reinforcement will be formed in response to the required pressure.

[Function] This method of manufacturing a hose forming an inner layer of sintered wear-resistant material is based on a core capable of forming an internal pressure, such as a mandrel coated with a cylindrical elastomer or an elastomer bag capable of enclosing water pressure or air pressure on a metal pipe. Since the required number of sintered material cylindrical units are set in a continuous state using a cylindrical body, the cylindrical units are evenly spaced, including loose fit and dimensional errors, and the steam drain during vulcanization is prevented. Intrusion of the flexible elastomer is prevented, and the flexible elastomer is filled in the gap of the step connection portion with sufficient gaps by internal and external pressure, and a suitable bond is formed.
In particular, in the case of an elastomer with a foamed composition, a more favorable filling state and a more flexible connection state can be obtained.

〔Example〕

FIG. 1 is a schematic longitudinal sectional view for explaining the operation of an example of a core body capable of forming internal pressure used in the present invention.

In the figure, 1 is an iron core, 2 is a fixing collar, 3 is a pressing collar, 4 is a tightening nut, 5 is a cylindrical elastomer, 6 is a sintered material cylindrical unit, and 7 is a half coupling for setting. This is an example in which sintered material cylindrical units are used for reinforcement in order to easily install them at equal intervals. The core body PCM, which is composed of the iron core 1, the fixing collar 2, the pressing collar 3, the tightening nut 4, and the cylindrical elastomer 5, is capable of forming an internal pressure, and when the tightening nut 4 is tightened, the pressing collar 3 moves. The cylindrical elastomer is compressed, preventing steam condensate from entering into the loose fitting part, and internal pressure is applied to the sintered material cylindrical unit to hold it evenly and firmly, and the axis of the cylindrical unit is aligned with the axis of the center body. This results in an even inner peripheral surface of the cylindrical unit and an even loosely fitted state.

FIG. 2 is a partially cross-sectional front view showing an example of a hose forming an inner layer of sintered wear-resistant material on a core body capable of forming internal pressure, and FIG. FIG. 4, a front view showing a partial cross section, is a modification of FIG. 3.

In the figure, 6 is a sintered material cylindrical unit; in this embodiment, alumina ceramics is used as the sintered material, and the required number of these units are loosely connected to form the sintered wear-resistant inner layer. .

This sintered material cylindrical unit 6 is formed in the shape shown in FIGS. 3 and 4. FIG. 3 shows one embodiment, and is a partially sectional front view. 6a is a large diameter part, FA is a large diameter loose fitting part,
It is formed to have an inner diameter larger than the outer diameter of the small diameter portion 6b,
When the small diameter portion 6b is inserted, it will be loosely fitted. 6
c is a step portion, and BA is a step connecting portion formed on the outside by the step diameter. In FIG. 4, a vertical step portion 6d is formed in contrast to the inclined step portion 6c of FIG.

The required number of sintered material cylindrical units 6 are placed on the core body shown in FIG. 2, which is capable of forming an internal pressure, by inserting the small diameter portion 6b into the large diameter loose fitting portion FA. A sintered material ring 8 having the same diameter as the small diameter portion 6b is placed at the end of the loose fitting portion FA, and an inner layer of sintered wear-resistant material is set by applying internal pressure using a core body capable of forming internal pressure.

Next, the sintered material ring 8 at the end and the ends of the large diameter part 6a and the small diameter part are joined with a joining elastomer 9, and the step connection between the sintered material cylindrical units 6 is made.
The space of BA is filled with flexible elastomer 10. In this case, if an elastomer with a foamed composition is used as the flexible elastomer 10, the elastomer with a foamed composition is arranged at an appropriate volume of 1/degree of foaming relative to the volume of the step connection part BA, as shown in FIG. The material is then filled and connected by foaming during vulcanization. An elastomer layer 11 is formed on the outer periphery of the sintered material cylindrical unit 6 and the step connection part BA, and a reinforcing layer 12 such as a required ply of organic fiber cord or steel cord layer coated with elastomer is applied to the outer peripheral surface of the elastomer layer 11 as required. Wrap the cord crosswise at the angle of the cord. Normally, the cord angle is such that reinforcing layers are set in groups of two plies that intersect with each other at cord angles inside and outside the resting angle (54° 45') of the hose with respect to the axis of the hose. Note that it is preferable that the elastomer layer 11 and the reinforcing layer 12 are formed integrally in advance and set at the same time.

Both ends of this reinforcing layer 12 are fixed by folding back the fixing ring 14, and this fixed part is attached to the flange 15.
It fits into the notch fitting portion 15a and is fixed with the joining elastomer 9. The outer surface of the reinforcing layer formed in this way is covered with an outer covering elastomer 13,
This constitutes a hose that is pressurized with a tightening cloth and heated and hardened at steam pressure in a vulcanizer to form an inner layer of sintered wear-resistant material. In this hose, the stepped connection part BA of the sintered material cylindrical unit 6 in a loosely connected state is connected with a flexible elastomer, so that although it has a structure of a rigid inner layer of sintered material, it is A,
As shown in B and C, flexibility such as declination, compression, and expansion can be obtained.

Note that when an elastomer with a foamed composition that is not a solid composition is used as the flexible elastomer, it is necessary to change the relationship between pressure and temperature in accordance with the foamed composition. Particularly at the end of vulcanization, it is necessary to cool the foamed elastomer sufficiently, and even after the end of heating, it is desirable to maintain the foamed body under air pressure until it is sufficiently cooled.

〔Effect of the invention〕

This invention makes it possible to use sintered materials with low precision by using a core body that can form internal pressure, and also makes it possible to reduce the level difference between rigid sintered material cylindrical units. The connecting parts can be connected almost evenly using a flexible elastomer, and a sintered wear-resistant inner layer is formed that provides flexibility in declination, compression, expansion, etc., so it provides long-term wear-resistant effects. This product greatly contributes to a highly practical hose that has a high level of durability that cannot be obtained with conventional hoses, and exhibits remarkable durability, especially against high temperatures.

[Brief explanation of drawings]

Fig. 1 is a functionally illustrative schematic vertical sectional view of an example of a core body capable of forming internal pressure used in the present invention, and Fig. 2 is a hose forming an inner layer of sintered wear-resistant material on the core body capable of forming internal pressure. FIG. 3 is a front view showing a 1/2 longitudinal section of a sintered material cylindrical unit; FIG. 4 is a modification of FIG. 3;
Figure 5 is a front view showing a 1/2 vertical section of a sintered material cylindrical unit in which a vertical step part is formed with respect to an inclined step part. Partial sectional view showing the combination of each member on the core body, Fig. 6-A, B, C
FIG. 2 is a longitudinal cross-sectional view showing the state of change in plasticity of the stepped connection portion of the sintered material cylindrical unit of the hose of the present invention. PCM...core body capable of forming internal pressure, 6 ...sintered material cylindrical unit, 6a...large diameter part, FA...large diameter loose fitting part, 6b...small diameter part, 6c, 6d...stepped part, BA
...Step connection part, 8... Sintered material ring, 9... Elastomer for joining, 10... Flexible elastomer, 11
...Elastomer layer, 12...Reinforcement layer, 13...Sheath elastomer.

Claims (1)

[Scope of Claims] 1. The required number of sintered material cylindrical units each having a stepped diameter and having both ends formed with a large-diameter loose fitting part and a small-diameter part on a core body capable of forming an internal pressure are mutually arranged. , insert the end of the small-diameter part into the large-diameter loose-fitting part, arrange it in a continuous state, apply internal pressure by the core body, loosely fit it in almost even positions, and then insert the inner layer of the sintered wear-resistant material. and set
A flexible elastomer is placed on the stepped connection portion formed on the outside of each sintered material cylindrical unit, an elastomer layer is formed on the outer periphery of the sintered material, and an organic fiber cord or an organic fiber cord coated with the elastomer is placed on the layer. A hose that forms an inner layer of a sintered wear-resistant material, characterized in that a reinforcing layer such as a steel cord layer is wound crosswise at a required cord angle, the outer surface is covered with an outer elastomer, and the whole is pressurized and heated to harden. manufacturing method. 2. The method for manufacturing a hose forming an inner layer of sintered wear-resistant material according to claim 1, wherein the core body capable of forming an internal pressure is a metal mandrel into which an elastomer cylinder is inserted. 3. Claim 1, wherein the core body capable of forming internal pressure is a core body in which an elastomer bag capable of enclosing water pressure or air pressure is formed on a hollow metal pipe.
A method for manufacturing a hose forming an inner layer of sintered wear-resistant material as described in 1. 4. The method for manufacturing a hose forming a sintered wear-resistant material inner layer according to claim 1, wherein the flexible elastomer of the step connection portion is a foamed elastomer.