JP6934809B2 - Three-dimensional laminated modeling product and three-dimensional laminated modeling method - Google Patents

Description

The present disclosure is for producing a three-dimensional laminated model product that can be manufactured by irradiating a laid powder material with a beam such as a light beam or an electron beam to perform laminated modeling, and the three-dimensional laminated model product. Regarding the three-dimensional laminated molding method.

A so-called laminated 3D printer technique is known in which a three-dimensional laminated model is manufactured by irradiating a powder material laid in layers with a beam such as a light beam or an electron beam to perform laminated modeling. In this technology, a powder bed made of a powder material is irradiated with a beam to form a sintered layer, and by repeating this process, a plurality of sintered layers are laminated as one to form a three-dimensional laminated molded product. Molding is done.

Such 3D printer technology has been developed as a manufacturing method for various shaped products in recent years, and one of its uses is, for example, a fuel used for a fuel injector of a liquid rocket engine shown in Patent Document 1. An injection element is conceivable. Conventionally, fuel injection elements are manufactured by combining multiple parts manufactured by machining, and the cost tends to be high, but by adopting 3D printer technology, a significant cost reduction is expected. Will be done.

Japanese Unexamined Patent Publication No. 2003-269254

In the laminated 3D printer technology, there is a problem that the surface roughness becomes large when an overhang shape in which the size of the modeled object increases toward the upper layer side when sequentially laminating from the lower layer side is included. In a fuel injection element as in Patent Document 1, conventionally, a male screw portion for engaging a peripheral member with an element body may be integrally formed, but an attempt was made to form this by 3D printer technology. In this case, the uneven shape of the male screw portion includes not a little overhang shape.

Here, FIG. 6 is a schematic view showing a cross-sectional shape of the male screw portion 22 included in the conventional fuel injection element 2. The male thread portion 22 has a single thread structure having an outer diameter a, a valley diameter b, a pitch p, and an effective diameter d, and proceeds when screwed into a peripheral member (not shown) having a corresponding female thread structure. It has an advancing flank 34 facing in the direction and a chasing flank 36 opposite the advancing flank 34. When such a male screw portion 22 is integrally molded together with the main body portion of the fuel injection element 2 by a laminated 3D printer technology, the follow-up flank 36 has an overhang shape. Assuming that the follow-up flank 36 with respect to the axis C of the male screw portion 22 is an overhang angle θ, when the overhang angle θ is 45 degrees or more, the surface roughness of the follow-up flank 36 becomes large, which makes it unusable for practical use ( FIG. 6 illustrates a case where the overhang angle θ is 60 degrees).

Therefore, when the fuel injection element 2 as shown in FIG. 6 is integrally molded by the 3D printer technology, it is necessary to form the male screw portion 22 having an overhang angle θ of less than 45 degrees as shown in FIG. However, if the overhang angle θ is reduced, the length L of the male screw portion 22 becomes large in order to secure the same number of pitches as in the case of FIG. 6, which leads to an increase in the size of the product.

Under these circumstances, when the fuel injection element 2 is manufactured by the conventional 3D printer technology, only the main body of the fuel injection element 2 is molded by the 3D printer technology, and the male screw portion 22 prepared as a separate body is used as the main body. It must be completed by assembling to the part. Therefore, the number of manufacturing processes increases, and the cost reduction effect of the 3D printer technology cannot be sufficiently obtained.

At least one embodiment of the present invention has been made in view of the above circumstances, and it is possible to effectively reduce the manufacturing cost while integrally molding the male screw portion with respect to the main body portion by using the laminated 3D printer technology. It is an object of the present invention to provide a three-dimensional laminated molding product and a three-dimensional laminated molding method.

(1) The three-dimensional laminated model product according to at least one embodiment of the present invention includes a main body portion and a male screw portion integrally projecting from the surface of the main body portion in order to solve the above problems. The male threaded portion has a trailing flank forming a first flank angle with respect to a plane perpendicular to the axis of the male threaded portion, and the first flank angle is 45 degrees or more.

According to the configuration of (1) above, since the first flank angle formed by the trailing flank with respect to the vertical plane of the axis has 45 degrees or more, the overhang angle formed by the male screw portion can be suppressed to less than 45 degrees. As a result, the surface roughness of the male screw portion can be suppressed to a practical range when it is formed by the 3D printer technology, and it can be integrally formed with the main body portion. As a result, the number of manufacturing steps can be reduced, and a more cost-effective three-dimensional laminated molded product can be obtained.

(2) In some embodiments, in the configuration of (1) above, the male screw portion has an advancing flank forming a second flank angle with respect to the vertical plane, and the second flank angle is the first flank angle. Smaller than the flank angle.

According to the configuration of (2) above, the second flank angle of the leading flank is smaller than the first flank angle of the chasing flank. As a result, the length of the male screw portion in the axial direction can be suppressed, so that it is possible to avoid an increase in the size of the product.

(3) In some embodiments, the second flank angle is zero degrees in the configuration of (2) above.

According to the configuration of (3) above, by setting the second flank angle to zero degree, the advancing flank of the male threaded portion becomes parallel to the vertical plane of the axis, and the length along the axial direction of the male threaded portion is increased. Can be the shortest. As a result, a more compact three-dimensional laminated model product can be obtained.

(4) In some embodiments, in any one of the above (1) to (3), the first flank angle is 70 degrees or less.

According to the configuration of (4) above, the upper limit of the first flank angle is 70 degrees. The larger the first flank angle is advantageous in that the overhang angle can be made smaller, but on the other hand, the durability against the axial force generated when the male screw portion is engaged is weakened. Considering the durability against such axial force, the first flank angle is preferably 70 degrees or less.

(5) In some embodiments, in any one of the above (1) to (4), the follow-up flank has a surface roughness with an arithmetic mean roughness (Ra) of 700 microinch or less.

According to the configuration of (5) above, the surface roughness of the trailing flank forming the overhang angle with respect to the vertical plane of the axis has an arithmetic mean roughness (Ra) of 700 microinch or less. Such surface roughness becomes a practical range because the overhang angle is suppressed to less than 45 degrees by having the first flank angle of 45 degrees or more.

(6) In some embodiments, in any one of the above (1) to (5), the main body is a fuel injection element used in a fuel injector of a liquid rocket engine, and the male thread is a male screw. By engaging with a nut having a female screw portion, a predetermined functional member can be sandwiched between the main body portion and the nut.

According to the configuration of (6) above, the above-mentioned three-dimensional laminated molded product (including the above-mentioned various aspects) is a fuel injection element used in a fuel injector of a liquid rocket engine. Conventionally, a fuel injection element is manufactured by combining a plurality of parts manufactured by machining, which is expensive, but as described above, it is costly to be formed by 3D printer technology. Can be reduced. In addition, since the overhang angle can be reduced by setting the first flank angle of the male threaded portion to 45 degrees or more, the surface roughness of the trailing flank can be suppressed within a practical range, so that the male threaded portion is integrated with the main body. It can be molded and the manufacturing process can be reduced.

(7) The three-dimensional laminated molding method according to at least one embodiment of the present invention includes a main body portion and a male screw portion integrally projected on the surface of the main body portion in order to solve the above problems. This is a three-dimensional laminated modeling method for irradiating a powder bed with a beam to form a laminated model of the original laminated model, and the first flank angle formed by the trailing flank with respect to the vertical plane of the axis of the male screw portion is 45. Form more than a degree.

According to the method (8) described above, the above-mentioned three-dimensional laminated modeled product (including the above-mentioned various aspects) can be suitably produced.

According to at least one embodiment of the present invention, a three-dimensional laminated molded product capable of effectively reducing the manufacturing cost while integrally forming a screw portion with the main body portion by using 3D printer technology, and a three-dimensional laminated product. A modeling method can be provided.

It is sectional drawing which shows the internal structure of the fuel injector of the liquid rocket engine which used the three-dimensional laminated model article which concerns on at least one Embodiment of this invention. It is an enlarged perspective view which shows the male thread part of FIG. 1 separated from the nut. It is sectional drawing which shows the cross-sectional structure of the male thread part of FIG. 1 in the state of being fitted with a nut. It is explanatory drawing which shows the modeling process by the three-dimensional laminated modeling method which concerns on at least one Embodiment of this invention step by step. This is another example of a three-dimensional laminated modeled product that can be modeled by the three-dimensional laminated modeling method of FIG. It is a schematic diagram which shows the cross-sectional shape of the male thread part included in the conventional fuel injection element. It is a modification of FIG.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, but are merely explanatory examples. No.
For example, expressions that represent relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a state of relative displacement with tolerances or angles and distances to the extent that the same function can be obtained.
Further, for example, the expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also includes a concavo-convex portion or a concavo-convex portion within a range in which the same effect can be obtained. The shape including the chamfered portion and the like shall also be represented.
On the other hand, the expressions "equipped", "equipped", "equipped", "included", or "have" one component are not exclusive expressions that exclude the existence of other components.

FIG. 1 is a cross-sectional view showing an internal structure of a fuel injector 1 of a liquid rocket engine in which a three-dimensional laminated model product according to at least one embodiment of the present invention is used. In the following embodiment, the fuel injection element 2, which is a component used in the fuel injector 1 of the liquid rocket engine, will be described as an example of one embodiment of the three-dimensional laminated model product according to the present invention, but other members. Needless to say, it may be.

A liquid rocket engine sends a combustor that burns fuel consisting of oxidizing agents, hydrogen, etc., a nozzle that generates thrust by expanding and accelerating the combustion gas generated by the combustor, and a propellant in the tank to the combustor. It is equipped with a propellant supply system. The propellant supply system includes a fuel injector 1 that mixes the oxidant and fuel accumulated in the propellant tank and injects them into the combustor.

As shown in FIG. 1, the fuel injector 1 includes a housing 4 formed integrally with or separately from the fuel injection element 2 having a circular cross section. The housing 4 defines a hydrogen chamber 8 in which liquid hydrogen is supplied from the propellant tank via the hydrogen supply passage 6, and an oxygen chamber 12 in which liquid oxygen is supplied from the propellant tank via the oxygen supply passage 10. .. A plurality of fuel injection elements 2 are formed so as to project downward from the partition wall 14 arranged between the hydrogen chamber 8 and the oxygen chamber 12. A face plate 18 that separates the hydrogen chamber 8 and the combustion chamber 16 defined in the combustor is fixed to the tip end side of the fuel injection element 2.

The fuel injection element 2 has a main body portion 20 extending along the axial direction, and a male screw portion 22 integrally formed with the main body portion 20 on the tip end side of the main body portion 20. The main body 20 communicates between the hydrogen chamber 8 and the combustion chamber 16, and forms a flow path for supplying liquid hydrogen from the hydrogen chamber 8 to the combustion chamber 16. A liquid hydrogen post 24, an oxygen chamber 12 and a combustion chamber 16 It has a liquid oxygen post 26 that communicates with each other and forms a flow path for supplying liquid oxygen from the oxygen chamber 12 to the combustion chamber 16. The liquid oxygen post 26 is formed so as to pass through the center of the fuel injection element 2 along the axis C, and the liquid hydrogen post 24 is a liquid oxygen post from a slit 28 opened in the side wall of the main body 20 with respect to the hydrogen chamber 8. It is formed so as to communicate with the combustion chamber 16 through the periphery of 26.

Further, the male screw portion 22 of the fuel injection element 2 is arranged concentrically with the main body portion 20, and extends downward from the main body portion 20 along the axis C. The male threaded portion 22 has a male threaded structure having threads arranged at a predetermined pitch. A nut 30 having a corresponding female screw structure is fitted in the male screw portion 22, and the above-mentioned face plate 18 is sandwiched between the nut 30 and the nut 30.

The face plate 18 sandwiched between the male screw portion 22 and the nut 30 is arranged so as to be partially in contact with the liquid hydrogen stored in the hydrogen chamber 8. Here, the face plate 18 is a functional member formed of a porous material, and the injection surface of the fuel injection element 2 is formed by permeating (exuding) a part of the liquid hydrogen stored in the hydrogen chamber 8. 32 is configured to be coolable.

FIG. 2 is an enlarged perspective view showing the male screw portion 22 of FIG. 1 separated from the nut 30, and FIG. 3 is a cross-sectional view showing the cross-sectional structure of the male screw portion 22 of FIG. 1 in a state of being fitted with the nut 30. ..
The male threaded portion 22 is a single thread having a male threaded structure having an outer diameter a, a valley diameter b, a pitch p, and an effective diameter d, and has a shape corresponding to the female threaded structure formed on the nut 30. The male threaded portion 22 has an advancing flank 34 facing the traveling direction when screwed into the nut 30, and a chasing flank 36 opposite the advancing flank 34.

Here, as shown in FIG. 3, the first flank angle α1, which is the angle of the trailing flank 36 with respect to the vertical plane P of the axis C of the male screw portion 22, and the advancing flank of the male screw portion 22 with respect to the vertical plane P of the axis C. A second flank angle α2, which is an angle of 34, is defined. Further, as will be described later with reference to FIG. 4, the fuel injection element 2 is formed by laminating molding from the main body portion 20 toward the male thread portion 22 along the vertical surface P, so that the fuel injection element 2 is overhanged at the time of laminating molding. The hang angle θ is defined as the angle of the trailing flank 36 with respect to the axis C and is equal to (90-α1) degrees.

Since the first flank angle α1 is set to 45 degrees or more, the overhang angle θ (= 90-α1) is suppressed to less than 45 degrees. In the present embodiment, an example in which the first flank angle α1 is set to 60 degrees is shown, and therefore the overhang angle θ is set to 30 degrees. As a result, the surface roughness of the male screw portion 22 is suppressed to a practical range when it is formed by the 3D printer technology. According to the verification of the inventor of the present application, the surface roughness of the follow-up flank 36 forming the overhang angle θ has an arithmetic mean roughness (Ra) of 700 microinch or less.

The first flank angle α1 is preferably 70 degrees or less. When the first flank angle α1 becomes large, it is advantageous that the follow-up flank 36 can make the overhang angle θ formed with respect to the vertical plane P of the axis C smaller, but on the other hand, the male screw portion 22 is engaged with the nut 30. Durability to the axial force generated when it is made is weakened. Considering the durability against such axial force, the first flank angle α1 is preferably 70 degrees or less.

The second flank angle α2 is set smaller than the first flank angle α1. As a result, the length L of the male screw portion 22 in the axis C direction can be suppressed. In the present embodiment, a case where the second flank angle α2 is set to zero degree is exemplified (in other words, the advancing flank 34 is formed so as to be the vertical plane P of the axis C). As a result, the advancing flank 36 of the male threaded portion 22 becomes parallel to the vertical plane P of the axis C, and the length L of the male threaded portion 22 along the axis C direction can be minimized, resulting in a more compact configuration. Be done.

Subsequently, a method of manufacturing the fuel injection element 2 having the above configuration will be described with reference to FIG. FIG. 4 is an explanatory diagram showing step by step the modeling process by the three-dimensional laminated modeling method according to at least one embodiment of the present invention.

In the present embodiment, molding is started from the main body portion 20 (upper side in FIGS. 2 and 3) having a relatively large volume among the fuel injection elements 2, and then the male screw portion 22 having a relatively small volume is molded. By molding in such an order, the overhang shape in the three-dimensional laminated molded product can be suppressed to a small extent, and high-quality molding becomes possible. In FIG. 4A, an intermediate state in which the main body 20 of the fuel injection element 2 is molded halfway is shown as an initial state.

As shown in FIG. 4B, the main body 20 is formed by laying the powder material supplied from the recoater 104 in a layer on the molding surface 102 on the base plate 100 as a base. To form. Then, as shown in FIG. 4C, the powder material is scanned by scanning the powder bed 106 on the modeling surface 102 while irradiating the powder bed 106 with a beam 108 such as a light beam or an electron beam from a beam irradiation unit (not shown). Is selectively solidified.

The powder material is a powdery substance that is a raw material for a three-dimensional laminated molded product, and for example, a metal material such as iron, copper, aluminum or titanium, and a non-metal material such as ceramic can be widely adopted.

The base plate 100 is configured to be able to move up and down along the vertical direction, and the step of forming the powder bed 106 shown in FIG. 4 (b) and the step of irradiating the beam 108 shown in FIG. 4 (c) are performed on the base plate 100. The molding of the main body 20 is advanced by repeating this while raising and lowering.

When the main body portion 20 is completed as shown in FIG. 4 (d), the molding of the male screw portion 22 is subsequently carried out continuously with the molding of the main body portion 20. The male threaded portion 22 is basically formed by repeatedly forming the powder bed 106 on the modeling surface 102 and irradiating the beam as in the main body portion 20, but the male threaded portion 22 is referred to with reference to FIGS. 2 and 3. As described above, the overhang shape is included in the follow-up flank 36. Therefore, in the molding of the male screw portion 22, the overhang angle θ is suppressed to 45 degrees or less by repeatedly forming the powder bed 106 and irradiating the beam so that the first flank angle α1 is 45 degrees or more. As a result, the surface roughness of the follow-up flank 36 has an arithmetic mean roughness (Ra) of 700 microinch or less, and can withstand practicality.

As described above, the male screw portion 22 is formed so that the overhang angle θ is 70 degrees or less, so that the durability against the axial force is sufficiently ensured. Further, the second flank angle α2 is implemented so as to be smaller than the first flank angle α1, so that the length L of the male screw portion 22 in the axis C direction may be suppressed. By suppressing the length L in this way, the molding time required for the laminated molding can be shortened, which is effective in reducing the cost. More preferably, the length L can be minimized by molding so that the second flank angle α2 becomes zero degree.

When the molding of the male screw portion 22 is completed as shown in FIG. 4 (e), the fuel injection element 2 is completed by removing the powder material remaining around the molded fuel injection element 2 (FIG. 4 (e). f)).

Note that FIG. 5 is another example of the three-dimensional laminated model product 110 that can be modeled by the three-dimensional laminated modeling method of FIG. Similar to the fuel injection element 2 described above, the three-dimensional laminated model 110 has a male screw portion 22 integrally molded with the flange portion 112 on the main body side, and particularly, the male screw portion 22 is formed along the circumferential direction of the flange portion 112. Are provided in multiples. At the time of modeling, such a three-dimensional laminated modeled product is also three-dimensionally laminated from the flange portion 112 on the main body side toward the plurality of male threaded portions 22, but each of the plurality of male threaded portions 22 is the first flank. By modeling so that at least one of the angle α1 and the second flange angle α2 has the above-mentioned angle range, the overhang angle θ can be suppressed as in the above-described embodiment.

As described above, according to the present embodiment, a three-dimensional laminated molded product capable of effectively reducing the manufacturing cost while integrally molding the male screw portion 22 with the main body portion 20 by using the laminated 3D printer technology. , And a three-dimensional laminated molding method can be provided.

At least one embodiment of the present invention is a three-dimensional laminated model product that can be manufactured by irradiating the laid powder with a beam such as a light beam or an electron beam to perform laminated modeling, and the three-dimensional laminated model product. It can be used as a three-dimensional laminated molding method for manufacturing.

1 Fuel injector 2 Fuel injection element 4 Housing 6 Hydrogen supply passage 8 Hydrogen chamber 10 Oxygen supply passage 12 Oxygen chamber 14 Partition 16 Combustion chamber 18 Face plate 20 Main body 22 Male thread 24 Liquid hydrogen post 26 Liquid oxygen post 28 Slit 30 Nut 32 Injection surface 34 Advancing side flank 36 Following side flank 100 Base plate 102 Modeling surface 104 Recorder 106 Powder bed 108 Beam 110 Three-dimensional laminated modeled product 112 Flange

Claims (7)

With the main body
A male screw portion that is integrally projected on the surface of the main body portion and
With
The male threaded portion has a trailing flank forming a first flank angle with respect to the vertical plane of the axis of the male threaded portion.
A three-dimensional laminated model product having a first flank angle of 45 degrees or more. The male thread portion has an advancing flank forming a second flank angle with respect to the vertical surface.
The three-dimensional laminated model product according to claim 1, wherein the second flank angle is smaller than the first flank angle. The three-dimensional laminated model product according to claim 2, wherein the second flank angle is zero degree. The three-dimensional laminated model product according to any one of claims 1 to 3, wherein the first flank angle is 70 degrees or less. The three-dimensional laminated molded product according to any one of claims 1 to 4, wherein the follow-up flank has a surface roughness having an arithmetic mean roughness (Ra) of 700 microinch or less. The main body is a fuel injection element used in a fuel injector of a liquid rocket engine.
Any one of claims 1 to 5, wherein the male screw portion is configured so that a predetermined functional member can be sandwiched between the main body portion and the nut by engaging with a nut having a female screw portion. The three-dimensional laminated model product described in. It is a three-dimensional laminated molding method for irradiating a powder bed with a beam to laminate a three-dimensional laminated model product including a main body portion and a male screw portion integrally projecting from the surface of the main body portion. hand,
A three-dimensional laminated molding method in which a first flank angle formed by a trailing flank is formed at 45 degrees or more with respect to a vertical plane of the axis of the male screw portion.

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