JP2004344944A - Casting method for sliding rotary body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a casting method for a sliding rotary body which can prevent the bias wear of the sliding rotary body. <P>SOLUTION: When casting a disk rotor as the sliding rotary body having the outer peripheral part circular in a plan view, a mold used for casting has a casting forming space C, a weir 10, and runners 11-14. The casting forming space C has the outer peripheral edge part circular in a plan view corresponding to the shape of the disk rotor. The weir 10, which makes the casting forming space C communicate with the runner 11, is installed so as to occupy 28%-100% of the entire periphery of the outer peripheral edge part (preferably, 100% of the entire periphery) in a position adjacent to the outer peripheral edge part of the casting forming space C. The disk rotor made of cast iron obtained by using the mold has a uniform microstructure (concretely, the graphite length) in arbitrary one circumference on the sliding face. As a result, the bias wear hardly occurs. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３９】
（結果の考察）
表１を参照しながら実施例と比較例とで鋳造方案の特徴を対比する。キャビティＣ１の周縁部全周に対する堰の占拠率ｓについては、実施例１〜４の占拠率ｓが２８％以上であるのに対し、比較例１及び２の占拠率ｓはその値よりも低くなっている。キャビティＣ１の周縁部全体の表面積に対する堰の連通断面積の比率（断面比）については、実施例１〜４の断面比が１１％以上であるのに対し、比較例１及び２の断面比はその値よりも低くなっている。堰とその隣接位置にある湯道との間の湯道堰比（ｓ・ｈ１／ｔ）については、実施例１〜４の湯道堰比が１．２０以上であるのに対し、比較例１及び２の湯道堰比はその値よりも低くなっている。
【００４０】
上述のような鋳造方案の差異は、各供試品における黒鉛長さの差及びブレーキ制動試験の結果に顕著に反映されている。まず黒鉛長さの差について言えば、実施例１〜４のいずれの供試品も、どの測定円周（面１外、面２外、面１内、面２内）においても黒鉛長さの差が１０μｍを超えることはなかった。これに対し、比較例１及び２の供試品では黒鉛長さの差が１０μｍを超える測定円周が存在している。つまり、実施例１〜４では同一測定円周内で黒鉛長さが比較的均一化しているのに対し、比較例１及び２では同一測定円周内で黒鉛長さに大きなバラツキを生じている。
【００４１】
ブレーキ制動試験での平均摩耗量については各実施例と比較例とで大きな違いはみられないが、試験後のディスク肉厚差については実施例と比較例とで顕著な差が生じた。即ち、実施例１〜４のいずれの供試品も試験後のディスク肉厚差が７μｍ以下であるのに対し、比較例１及び２の供試品では試験後のディスク肉厚差が１１μｍ以上となっており、ディスク偏摩耗の兆候が見られた。経験則によれば、ディスク肉厚差が１０μｍを超えると、実車でのブレーキ振動の発生率が急激に高くなる。つまり、実施例１〜４の供試品ではディスク偏摩耗に起因するブレーキ振動が顕在化する可能性が極めて低いが、比較例１及び２の供試品ではディスク偏摩耗に起因するブレーキ振動が顕在化する可能性が非常に高い。
【００４２】
このように、実施例１〜４の鋳造方案によれば、ディスクロータの第１及び第２摺動面上の任意の円周内において黒鉛長さを比較的均一化することができる。そして、実施例１〜４の鋳造方案に従ったディスクロータは、使用時にある程度の摩耗はするものの、偏摩耗は起こし難いという優れた特性を有する。
【００４３】
【発明の効果】
本発明の摺動回転体の鋳造方法によれば、比較的簡易な鋳造方案で、摺動回転体表面上の任意の円周内において組織（例えば黒鉛形態）がほぼ均一化した摺動回転体を鋳造することができる。特に本発明の鋳造方法は、従来技術と異なり特殊な材料や高エネルギーを必要とせず、ごく普通の材料を用いて実施可能な汎用性の高い技術であるため、ＬＣＡ（ライフサイクルアセスメント）的にも優れている。そして、この鋳造方法で作られた摺動回転体は、従来の鋳造方案に従った摺動回転体よりも偏摩耗し難いという特徴を有する。
【図面の簡単な説明】
【図１】実施例１の鋳造方案の概略を示す断面図。
【図２】（Ａ）実施例１の鋳造方案から得られる一次製品の平面図、（Ｂ）実施例１の二次製品（供試品）の部分断面図。
【図３】実施例２の鋳造方案の概略を示す断面図。
【図４】（Ａ）は実施例３における一次製品の底面図、（Ｂ）及び（Ｃ）は実施例３の鋳造方案の一部概略断面図。
【図５】（Ａ）は実施例４における一次製品の底面図、（Ｂ）及び（Ｃ）は実施例４の鋳造方案の一部概略断面図。
【図６】（Ａ）は比較例１の鋳造方案の平面図、（Ｂ）は比較例２の鋳造方案の平面図、（Ｃ）は比較例１及び２の鋳造方案の一部概略断面図。
【図７】ブレーキ制動試験での実施例２の摩耗量測定結果を示すグラフ。
【図８】ブレーキ制動試験の前後における実施例２のディスク厚みの変化を示すグラフ。
【符号の説明】
１…上型、２…下型、３…中子（１〜３は鋳型を構成する）、１０…鋳物成形空間の外周縁部に隣接する堰、１１…堰の外側隣接位置にある湯道、１２，１３，１４…湯道、２０…鋳物成形空間の内周縁部に隣接する堰、２１…堰の内側隣接位置にある湯道、２２…トンネル湯道、２３，２４，２５…堰、Ｃ，Ｃ１，Ｃ２…キャビティ（鋳物成形空間）。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for casting a sliding rotor such as a disc rotor for a disc brake, a drum for a brake or a flywheel for a clutch.
[0002]
[Prior art]
In an automobile disk brake, if the disk rotor is unevenly worn and its thickness varies, the pad rotor (friction material) is displaced during braking due to the uneven wear, which causes uncomfortable vibration for passengers (called brake vibration). ) Is known to make you feel. Since the occurrence of the brake vibration not only makes the braking unstable but also reduces the running stability, prevention of uneven wear of the disk rotor is an important technical problem. For example, in Patent Document 1, by adding a metal element such as Ni, Mo, Cu, Cr, or V to flaky graphite cast iron, the base structure is changed to a martensite structure or a pearlite structure to improve the wear resistance of the disk. I have. In Patent Document 2, a base material (cast iron) is irradiated with a laser beam and subjected to a remelting treatment to form a hardened layer having a chill and martensite structure, thereby improving the wear resistance of the disk.
[0003]
[Patent Document 1] JP-A-6-65673
[Patent Document 2] JP-A-5-157134
[0004]
[Problems to be solved by the invention]
According to the above-mentioned conventional technique, the wear resistance of the disk rotor can be improved, but consideration must be given to the global environment in terms of adding special metals and requiring high energy. Chip. In addition, the wear resistance of the disk is unnecessarily improved, and the disk may slip on contact with the pad, and the original effect (frictional force) of the brake may not be obtained.
[0005]
The present invention is not only from the viewpoint of simply improving the wear resistance of the sliding rotating body, but as a technology for preventing uneven wear of the sliding rotating body from a completely different viewpoint from the conventional one. A casting method is provided.
[0006]
[Means for Solving the Problems]
(Background explanation of the idea)
The inventor of the present invention has studied for many years the technology of manufacturing a disc rotor for a cast iron brake, which is a typical sliding rotating body, and as a result of the study, it was found that "a difference in the amount of wear due to a difference in the structure" is one of the causes of uneven wear of the disc. Was found. The “structure difference” referred to here includes a difference in base structure that appears as a difference in hardness and a difference in graphite morphology contained in cast iron. Furthermore, the inventor has found that the graphite morphology in the cast product is closely related to the casting conditions and that most of the graphite morphology is determined during solidification of the molten metal (Knowledge 1), and that graphite wear occurs at the interface between graphite and the matrix structure. It is understood that a change in graphite morphology correlates with a change in interface length (knowledge 2), and that the graphite structure adheres to the pad and greatly affects the development of frictional force (knowledge 3).
[0007]
Based on the above technical knowledge, the present inventor uses a graphite length that can be quantitatively expressed as an index representing the graphite morphology of a cast iron product, and the graphite length is used to determine the wear of a sliding sliding body made of cast iron (particularly brakes). Effect of the disc on the disc) was clarified through various trial production experiments. Generally, when an object having a disk shape or a cylindrical shape (that is, having a circular outer peripheral portion or an inner peripheral portion in a plan view state) such as a brake disk rotor is made by casting, a circle in a plan view corresponding to the shape is formed. A mold for constructing a cavity (casting space) having an outer peripheral edge and / or an inner peripheral edge of the shape is used. As a result of a trial production experiment, the way of the weir connecting the cavity and the runner is determined through the weir. Thus, it was found that the solidification rate or the cooling rate of the molten metal poured into the cavity was greatly affected. By devising a casting method as described below, the variation in the graphite length is reduced in a region along the circumference of the sliding rotating body (that is, the graphite length is made uniform), and the sliding rotating is performed. We succeeded in reducing the uneven wear of the body compared to the past.
[0008]
(Means and actions)
The present invention is a method for casting a sliding rotating body having a circular outer peripheral portion or an inner peripheral portion in a plan view using a mold having a casting molding space, a weir and a runner, wherein the casting molding is performed. The space has an outer peripheral edge or an inner peripheral edge having a circular shape in plan view corresponding to the shape of the sliding rotating body, and a weir for communicating the casting molding space with the runner is provided at the outer peripheral edge of the casting molding space. It is characterized by being installed so as to occupy 28% to 100% of the entire circumference of the outer peripheral edge or the inner peripheral edge at a position adjacent to the portion or the inner peripheral edge.
[0009]
According to this casting method, the weir that connects the casting molding space constructed in the mold to the runner exists at a position adjacent to the outer peripheral edge or the inner peripheral edge of the casting molding space, and is outside the casting molding space. It is installed so as to occupy 28% to 100% of the entire periphery of the periphery or the inner periphery. As described above, the occupancy ratio of the weir to the entire periphery of the outer peripheral edge or the inner peripheral edge of the casting molding space is sufficiently large, so that, at the time of pouring, the weir of the outer peripheral edge or the inner peripheral edge of the casting molding space. A large difference in the amount of heat hardly occurs between the part directly communicating (direct communication part) and the other part (non-communication part) not directly communicating with the weir. In other words, the calorie distribution of the molten metal is substantially uniform between the directly communicating portion into which the molten metal is directly poured via the weir and the non-communicating portion which receives the supply of the molten metal via the directly communicating portion. Even if a thermal gradient occurs in the casting space, the thermal gradient exists in the radial direction of the casting space, and the isothermal points in that case are concentrically distributed and are substantially isothermal within the same circumference having the same radius. . For this reason, even in the solidification cooling process after pouring, the solidification rate or cooling rate is uniform within an arbitrary circumference in the casting molding space, and the structure (for example, the graphite form using the graphite length as an index) within the same circumference. ) Becomes easier. The structure of the sliding rotator obtained by this casting method (for example, graphite) is uniform within an arbitrary circumference around the rotation axis, so that the sliding rotator according to the conventional casting method can be used. It has the characteristic that uneven wear is less likely to occur.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
In the section of “Embodiments of the invention”, more preferable aspects and additional constituent features of the present invention will be described.
[0011]
The casting object of the present invention is a sliding rotator having a circular outer or inner peripheral portion in a plan view, and is an object which is axisymmetric when rotated about a rotation axis. When casting the sliding rotating body, a mold having a casting molding space, a weir, and a runner is used. The mold is a concept including a main mold and a core disposed therein. For example, the main mold and the core form a casting molding space (cavity) in the shape of a sliding rotating body as a casting object. Is done. As a constituent material of the main mold and the core, so-called sand (eg, green sand, shell sand) can be exemplified. The weir and the runner set in the mold constitute at least a part of the gate system.
[0012]
The casting molding space has an outer peripheral edge or an inner peripheral edge of a circular shape in plan view corresponding to the shape of the sliding rotating body, and a weir that communicates the casting molding space with the runner is provided in the casting molding space. It is installed so as to occupy 28% to 100% (more preferably 39% to 100%) of the entire outer periphery or inner periphery at a position adjacent to the outer periphery or the inner periphery. When the occupation ratio (s) of the weir to the entire periphery of the casting molding space is less than 28%, the supply of the molten metal is performed through the direct communication part where the molten metal is directly poured through the weir and the direct communication part. It is difficult to make the calorific value distribution of the molten metal uniform with the non-communicating portion to be received, and there is a possibility that uneven wear of the sliding rotating body cannot be reduced.
[0013]
In the present invention, it is ideal that the occupancy ratio (s) of the weir to the entire periphery of the casting molding space is 100%. That is, it is preferable that the weir is installed so as to occupy the entire periphery of the outer periphery or the inner periphery at a position adjacent to the outer periphery or the inner periphery of the casting molding space (that is, s = 100%). . In this case, the weir is a single weir having an annular shape in a plan view. Alternatively, a plurality of weirs that are discontinuous with each other may exist. That is, there are a plurality of weirs at positions adjacent to the outer peripheral edge or the inner peripheral edge of the casting molding space, and the plurality of weirs accounts for 28% of the entire circumference of the outer peripheral edge or the inner peripheral edge of the casting molding space. Preferably, it is installed so as to occupy １００100% (more preferably 39% to 100%).
[0014]
In the present invention, the setting of the communication sectional area in the communication relationship between the casting molding space and the weir is also an important factor. That is, at a position where at least a part of the casting molding space and the weir are directly connected, the ratio of the communication cross-sectional area of the weir to the surface area of the entire periphery of at least a part of the outer peripheral edge or the inner peripheral edge of the casting molding space ( It is preferable that the size of the weir is set so that the cross section ratio is 10% to 60% (more preferably, 20% to 60%). When the ratio (cross-sectional ratio) of the communication cross-sectional area of the weir is less than 10%, the pouring speed of the molten metal poured into the casting molding space via the weir becomes extremely slow, and the direct communication portion into which the molten metal is directly poured. Then, it may be difficult to make the calorific value distribution of the molten metal uniform with the non-communicating portion that receives the supply of the molten metal via the direct communicating portion. On the other hand, if the ratio of the cross-sectional area of the weir (cross-sectional ratio) exceeds 60%, it becomes difficult to distinguish between the weir and the casting molding space, and the significance of the existence of the weir (that is, by restricting the flow of the molten metal with the weir, the impurities). Of preventing molten metal from entering and making the flow of the molten metal as uniform as possible) may be lost.
[0015]
In the present invention, the dimensional relationship between the weir and the runner adjacent thereto is also an important factor. That is, the outer or inner adjacent position of the weir occupies a range corresponding to 70% to 100% of the entire circumference of the outer peripheral edge or the inner peripheral edge of the casting molding space, with the bottom being lower than the weir. It is preferable that a runner is provided, and further, the ratio (h1 / t) of the height (h1) of the runner to the height (t) of the weir corresponds to the outer peripheral edge portion or the inner portion of the casting molding space. The runner weir ratio (s · h1 / t) obtained by multiplying the occupancy rate (s) of the weir to the entire periphery of the peripheral part is a value of 1.2 or more (more preferably a value of 1.2 to 7.0). It is preferable that the dimensions of the runner be set so as to satisfy ()). When the runner weir ratio (s · h1 / t) is less than 1.2, the pouring speed of the molten metal poured from the runner through the weir into the casting molding space becomes extremely slow, and the molten metal is directly poured. There is a possibility that it may be difficult to make the calorific value distribution of the molten metal uniform between the direct communication portion and the non-communication portion receiving the supply of the molten metal via the direct communication portion. On the other hand, when the runner weir ratio (s · h1 / t) exceeds 7.0, it becomes difficult to distinguish between the weir and the runner, and the existence significance of the weir (that is, by reducing the flow of the molten metal at the weir, the impurities are removed). Of preventing molten metal from entering and making the flow of the molten metal as uniform as possible) may be lost.
[0016]
Examples of the casting material (molten metal) used in this casting method include iron-based metals such as cast iron. In particular, it is preferable to use flaky graphite cast iron among iron-based metals. When the casting material is flaky graphite cast iron, it is possible to make the graphite structure uniform within an arbitrary circumference on the sliding surface of the sliding rotating body obtained by casting.
[0017]
As a preferred embodiment when the weir is installed adjacent to the outer peripheral edge of the casting molding space, a casting scheme as shown in FIG. 1 can be exemplified. This is a method of casting a ventilated disk rotor (Example 1 will be described later as a specific example). In FIG. 1, a casting molding space (cavity) C is constructed in a mold by a main mold including an upper mold 1 and a lower mold 2 and a core 3 arranged therein. The cavity C includes a cavity C1 involved in casting the lower sliding plate of the two sliding plates constituting the ventilated disk rotor, and a cavity C2 involved in casting the upper sliding plate. And at least exists.
[0018]
Preferably, the weir 10 is installed at a position adjacent to the outer peripheral edge of the casting molding space C so as to occupy or surround the entire periphery of the outer peripheral edge (that is, the occupancy rate s = 100%). At a position adjacent to the outside of the weir 10, a first runner 11 whose bottom is lower than the weir 10 and occupies a range corresponding to 70% to 100% of the entire outer peripheral edge of the casting molding space C is provided. Will be installed. The height h1 of the first runner 11 is preferably set to 1.5 times or more, more preferably 2 to 7 times, the height or thickness t of the weir 10.
[0019]
Preferably, a second runner 12 is provided at a position outside and adjacent to the first runner 11. It is preferable that the second runner 12 is a plate runner, and furthermore, it is a full circumference runner that surrounds the entire casting molding space C in a ring shape. The height h2 of the second runner 12 is preferably set to 1.5 times or more, more preferably 1.5 to 3 times, the height t of the weir 10. More preferably, at a position outside the second runner 12 adjacent to the outside, the bottom is lower than the second runner 12 and occupies or surrounds at least 50% of the circumference of the second runner 12. A third runner 13 is installed. The height h3 of the third runner 13 is preferably set to be at least twice the height t of the weir 10, more preferably 2.5 to 15 times. In addition, as shown in FIG. 1, it is preferable to provide a fourth runner 14 for guiding the molten metal from the gate (not shown) to the third runner 13 at a position outside the third runner 13. .
[0020]
As a preferred embodiment when the weir is installed adjacent to the inner peripheral edge of the casting molding space, a casting method as shown in FIG. 3 can be exemplified. This is a casting method of a ventilated disk rotor (embodiments 2, 3 and 4 will be described later as specific examples). In FIG. 3, a casting mold space (cavity) C is constructed in a mold by a main mold including an upper mold 1 and a lower mold 2 and a core 3 disposed therein. The cavity C includes a cavity C1 involved in casting the lower sliding plate of the two sliding plates constituting the ventilated disk rotor, and a cavity C2 involved in casting the upper sliding plate. And at least exists.
[0021]
Preferably, the weir 20 is installed at a position adjacent to the inner peripheral edge of the casting forming space C so as to occupy the entire outer peripheral edge or a part thereof. At a position adjacent to the inside of the weir 20, a runner 21 whose bottom is lower than the weir 20 and occupies a range corresponding to 70% to 100% of the entire inner peripheral edge of the casting space C is installed. . The height h1 of the runner 21 is preferably set to 1.5 times or more, more preferably 2 to 7 times, the height or thickness t of the weir 20. In addition, as shown in FIG. 3, while extending around the casting forming space C, the weir 20, and the runner 21 in the radial direction of the mold while bypassing them, the molten metal from the gate (not shown) is fed to the runner 21. It is preferred to provide a tunnel runner 22 for guiding.
[0022]
An advantage of disposing the weir adjacent to the inner peripheral edge of the casting molding space (cavity) is that the density of installation of the cavity in one frame of the casting equipment can be increased (the weir is located on the outer peripheral edge of the cavity). In comparison with the case where it is installed in
[0023]
【Example】
Examples 1 to 4 in which the present invention is embodied in a casting method of a ventilated disk rotor and Comparative Examples 1 and 2 belonging to the category of the prior art will be described. Incidentally, when producing a disk rotor for each of Examples and Comparative Examples, two types of flaky graphite cast iron (cast iron equivalent to FC200 and cast iron equivalent to FC150) were used. In the preparation of molten metal, gray cast iron return material, steel scrap, carburizing material and Fe-Si alloy are melted in a high-frequency induction furnace, and an inoculant (Fe-75% Si) is added at the time of tapping from the induction furnace. To adjust the components. The composition of FC200 after component adjustment is C: 3.37%, Si: 2.16%, Mn: 0.57%, P: 0.046%, and S: 0.082%. Further, the composition of FC150 after the component adjustment is C: 3.82%, Si: 2.08%, Mn: 0.61%, P: 0.051%, and S: 0.080%.
[0024]
(Example 1)
In the casting method according to the first embodiment shown in FIG. 1, the plate-shaped weir 10 (height t = 2 mm, horizontal distance = 5 mm) is provided at the outer peripheral edge of the cavity C1 involved in the casting of the disk rotor lower sliding plate. (S = 100%). The entire runner 11 along the entire outer periphery of the weir 10 has a height h1 = 10 mm and a radial length of about 10 mm. Six core fixing pedestals (not shown) for supporting and fixing the core 3 for forming the air holes of the disk rotor are arranged inside the all-round hot runner 11. Since the occupancy rate in the runner per core fixing base is 1.3%, the runner 11 substantially occupies 92.2% (= 100-1.3 × 6) of the entire circumference of the weir 10. I do. The plate-shaped full-peripheral runner 12 along the entire outer periphery of the runner 11 has a height h2 = 4 mm and a radial length of about 5 mm. The perimeter runner 13 along the entire outer periphery of the plate-shaped perimeter runner 12 has a height h3 = 25 mm and a length in the radial direction of about 20 mm. The semi-peripheral runner 14 along the range of about 40% of the entire outer periphery of the perimeter runner 13 has a height h4 = 15 mm and a radial length of about 15 mm. The runner 14 is set to the upper mold 1, and the other weirs and the runners 10 to 13 are set to the lower mold 2. The runner 14 and the runner 13 overlap each other by 5 mm in the radial direction, and the runner 14 is connected to the gate. In the casting method of the first embodiment, the occupation ratio s of the weir 10 with respect to the entire outer peripheral edge of the cavity C1 is 100%, and the ratio of the communication cross-sectional area of the weir 10 to the total surface area of the outer peripheral edge of the cavity C1 (cross-sectional ratio) ) Is 22%. Also, h1 / t = 10/2 = 5, h2 / t = 4/2 = 2, h3 / t = 25/2 = 12.5. Since s = 100%, the runner weir ratio (s · h1 / t) between the weir 10 and the runner 11 is 5.00 (see Table 1 below).
[0025]
The molten metal (flake graphite cast iron) supplied from the gate reaches the runner 11 via the runner 14, the runner 13 and the plate runner 12, and fills the runner. Then, the molten metal runs over the entire circumferential weir 10 from the annular runner 11 in a plan view, and is poured almost simultaneously into the entire outer peripheral edge of the cavity C <b> 1, and finally fills the entire cavity C. FIG. 2A shows the primary product when it is taken out of the mold immediately after the completion of casting. Primary products are accompanied by extra meat from the weirs and runners. In this figure, six through-holes 15 existing in the runner 11 among the excess meat portions are traces (removed traces) of the core fixing base. Note that the plan cross section of FIG. 1 corresponds to a cross section along the line AA in FIG. Excessive flesh was removed from the primary product, the surface was cut with a machining allowance of 2 mm, and then each sliding surface was mirror-polished to obtain a secondary product (sample). .
[0026]
Then, the graphite length was measured along a specific circumference on each sliding surface of the rotor sliding plate portion of the secondary product. That is, as shown in FIG. 2 (B), one circumference (referred to as “outside of surface 1”) located 2 mm inside from the outermost periphery of the first sliding surface of the secondary product, and the innermost of the first sliding surface. One circumference located 2 mm outside of the circumference (called “inside 1”), one circumference located 2 mm inside from the outermost circumference of the second sliding surface (called “outside of surface 2”), and One circumference (referred to as “inside 2”) located 2 mm outside from the innermost circumference of the two sliding surfaces was selected as a portion to be measured for graphite length. At the time of measurement, each circumference was divided into 30 equal parts, each part was observed with an optical microscope (magnification: 100 times), and an image of graphite structure was sampled and subjected to image processing. "Graphite length" is defined as the length of the major axis of an ellipse circumscribing one continuous flaky graphite, and the average value of the graphite length measured in one field of view (0.9 mm x 0.5 mm) Was the graphite length at the sampling point. Then, the difference between the maximum value and the minimum value of the graphite length in 30 places on one circumference was defined as the "difference in graphite length" in the circumference. Table 1 shows the measurement results of the difference in graphite length in the secondary product (test sample) obtained in Example 1.
[0027]
(Example 2)
In the casting method according to the second embodiment shown in FIG. 3, the plate-shaped weir 20 (height t = 3 mm, horizontal distance 5 mm) is formed around the entire inner periphery of the cavity C1 for casting the disk rotor lower sliding plate. (S = 100%). The entire runner 21 along the entire inner periphery of the entire weir 20 has a height h1 = 10 mm and a length in the radial direction of about 15 mm. The tunnel runner 22 has a height h5 = 10 mm and a width of 50 mm. In the casting method of the second embodiment, the occupation ratio s of the weir 20 to the entire inner peripheral edge of the cavity C1 is 100%, and the ratio of the cross-sectional area of the weir 20 to the surface area of the entire inner peripheral edge of the cavity C1 (cross-sectional ratio) ) Is 33%. H1 / t = 10/3 = approximately 3.33. Since s = 100%, the runner weir ratio (s · h1 / t) between the weir 20 and the runner 21 is about 3.33 (see Table 1 below).
[0028]
The primary product obtained based on the casting method of Example 2 was subjected to the same post-processing as in Example 1 to obtain a secondary product (sample). And the graphite length measurement similar to the said Example 1 was performed about the secondary product. Table 1 shows the measurement results of the difference in graphite length in the secondary product (test sample) of Example 2.
[0029]
(Example 3)
4 (B) and 4 (C) show schematic cross sections of the casting method of the third embodiment, and FIG. 4 (A) shows the bottom surface of a primary product obtained from the casting method of the third embodiment. The plan section of FIG. 4B corresponds to the section taken along line XX of FIG. 4A, and the plan section of FIG. 4C corresponds to the section taken along line YY of FIG. 4A. The casting method according to the third embodiment corresponds to a case where the entire circumferential weir 20 according to the second embodiment is divided into a plurality of parts in order to improve the weir foldability. That is, five dams 23 are provided along the inner peripheral edge of the cavity C1 for casting the disk rotor lower sliding plate. Each weir 23 has a height t = 3.5 mm, a horizontal distance of 15 mm, and a circumferential width of 40 mm. The entire circumference runner 21 provided inside these weirs 23 has a height h1 = 15 mm and a radial length of about 20 mm. The five weirs 23 are arranged at equal angular intervals in a range excluding a joint portion between the entire circumference runner 21 and the tunnel runner 22 (height h5 = 10 mm, width 50 mm). In the casting method of the third embodiment, the total occupation ratio s of the five weirs 23 with respect to the entire inner peripheral edge of the cavity C1 is 39%, and the communication cross-sectional area of the five weirs 23 with respect to the surface area of the entire inner peripheral edge of the cavity C1. Is 15%. H1 / t = 15 / 3.5 = about 4.3. Since s = 39%, the runner weir ratio (s · h1 / t) between the five weirs 23 and the runner 21 is about 1.67 (see Table 1 below).
[0030]
The primary product obtained based on the casting method of Example 3 was subjected to the same post-processing as in Example 1 to obtain a secondary product (sample). And the graphite length measurement similar to the said Example 1 was performed about the secondary product. Table 1 shows the measurement results of the difference in graphite length in the secondary product (test sample) of Example 3.
[0031]
(Example 4)
5 (B) and 5 (C) show schematic cross sections of the casting method of the fourth embodiment, and FIG. 5 (A) shows the bottom surface of a primary product obtained from the casting method of the fourth embodiment. The plan section of FIG. 5B corresponds to the cross section taken along line XX of FIG. 5A, and the plan section of FIG. 5C corresponds to the cross section taken along line YY of FIG. 5A. The casting method according to the fourth embodiment corresponds to one obtained by dividing the entire circumferential weir 20 of the second embodiment into a plurality in order to improve the weir foldability. That is, three dams 24 and 25 are provided along the inner peripheral edge of the cavity C1 for casting the disk rotor lower sliding plate. The weir 24 located on the opposite side of the connection between the entire runner 21 (height h1 = 15 mm, radial length about 20 mm) and the tunnel runner 22 (height h5 = 10 mm, width 50 mm) has a height t = 3. 0.5 mm, horizontal distance 15 mm, width 60 mm in the circumferential direction. Each of the two weirs 25 located 90 degrees to the left and right of the weir 24 has a height t = 3.5 mm, a horizontal distance of 15 mm, and a circumferential width of 40 mm. The entire circumference runner 21 is inside these weirs 24 and 25. In the casting method of the fourth embodiment, the total occupancy s of the three weirs 24 and 25 with respect to the entire inner peripheral edge of the cavity C1 is 28%, and the three weirs 24 and 25 with respect to the surface area of the entire inner peripheral edge of the cavity C1. Is 11%. H1 / t = 15 / 3.5 = about 4.3. Since s = 28%, the runner weir ratio (s · h1 / t) between the three weirs 24 and 25 and the runner 21 is 1.20 (see Table 1 below).
[0032]
The primary product obtained based on the casting method of Example 4 was subjected to the same post-processing as in Example 1 to obtain a secondary product (sample). And the graphite length measurement similar to the said Example 1 was performed about the secondary product. Table 1 shows the measurement results of the difference in graphite length in the secondary product (test sample) of Example 4.
[0033]
In the third embodiment, each weir is narrowed to improve the weir foldability, while increasing the number of weirs to compensate for the filling property of the molten metal. On the other hand, the fourth embodiment is a method for improving the fillability of the molten metal by increasing the width of each weir and increasing the fillability of the molten metal, while reducing the number of weirs.
[0034]
(Comparative Example 1 and Comparative Example 2)
FIG. 6A shows a planar arrangement of the casting method of Comparative Example 1. In Comparative Example 1, six cavities C are provided in one frame 31 and one weir 32 is provided for one cavity C. On the other hand, FIG. 6B shows a plan layout of the casting method of Comparative Example 2. In Comparative Example 2, six cavities C are arranged in one frame 31 and three weirs 32 are provided for one cavity C. In each of the comparative examples, the weir 32 is connected to a gate 34 through a runner 33 that runs in a broken line in the frame 31. Each weir 32 is installed in the lower mold 2 (see FIG. 6C).
[0035]
In the casting method of Comparative Example 1, the occupation ratio s of the weir 32 with respect to the entire outer peripheral edge of the cavity C1 is 7%, and the ratio of the communicating cross-sectional area of the weir 32 to the surface area of the entire outer peripheral edge of the cavity C1 (cross-sectional ratio) ) Is 4%, the height of the weir 32 is t = 5 mm, the height of the runner 33 is h1 = 20 mm, and the ratio of the runner weir between the weir 32 and the runner 33 (s · h1 / t). Is 0.28. On the other hand, in the casting method of Comparative Example 2, the total occupancy s of the three weirs 32 with respect to the entire outer peripheral edge of the cavity C1 is 13%, and the three weirs 32 communicate with the entire surface area of the outer peripheral edge of the cavity C1. The cross-sectional area ratio (cross-sectional ratio) is 6%, the height t of the weir 32 is 4 mm, the height h1 of the runner 33 is 15 mm, and the runner between the three weirs 32 and the runner 33 The weir ratio (s · h1 / t) is about 0.49.
[0036]
The primary product obtained based on the casting scheme of each comparative example was subjected to the same post-processing as in Example 1 to obtain a secondary product (sample). And the graphite length measurement similar to the said Example 1 was performed about the secondary product. Table 1 shows the measurement results of the difference in graphite length between the secondary products (test samples) of Comparative Examples 1 and 2.
[0037]
(Brake braking test)
For each of the test samples of Examples 1 to 4 and Comparative Examples 1 and 2, a brake braking test was performed in an actual brake use environment, and the wear state of each test sample was investigated. First, the wear amount was measured at every rotor angle of 30 degrees on one circumference of 10 mm from the outermost circumference of the disk of each sample, and the average value thereof was defined as the average wear amount. FIG. 7 shows the measurement results of the wear amount for Example 2 (FC150). From the results in FIG. 7, it was found that the average wear amount of Example 2 (FC150) was 110 μm (micrometer). Before the brake braking test, the change in the thickness of the disk (ie, the distance between the first sliding surface and the second sliding surface) on one circle inside 10 mm from the outermost periphery of the disk of each test sample was measured. And later measured. The upper graph of FIG. 8 shows the change in the thickness of the disk of Example 2 (FC150) before the brake braking test, and the lower graph of FIG. 8 shows the thickness of the disk of Example 2 (FC150) after the brake braking test. Indicates a change. The difference between the maximum value and the minimum value in each of the graphs before and after the test is a thickness difference that is a factor of brake vibration. From this result, it was found that the thickness difference before the test of Example 2 (FC150 product) was 3 μm, and the thickness difference after the test was 5 μm. Similar measurements were performed for other examples and comparative examples. Table 1 shows the results.
[0038]
[Table 1]

[0039]
(Discussion of results)
With reference to Table 1, the features of the casting method will be compared between the embodiment and the comparative example. Regarding the occupancy s of the weir with respect to the entire periphery of the cavity C1, the occupancy s of Examples 1 to 4 is 28% or more, whereas the occupancy s of Comparative Examples 1 and 2 is lower than that value. Has become. Regarding the ratio of the cross-sectional area of the weir to the surface area of the entire peripheral portion of the cavity C1 (cross-sectional ratio), the cross-sectional ratio of Examples 1 to 4 is 11% or more, whereas the cross-sectional ratio of Comparative Examples 1 and 2 is It is lower than that value. Regarding the runner weir ratio (s · h1 / t) between the weir and the runner located adjacent to the weir, the runner weir ratio in Examples 1 to 4 is 1.20 or more, while the comparative example The runner weir ratio of 1 and 2 is lower than that value.
[0040]
The difference in the casting method as described above is remarkably reflected in the difference in the graphite length in each specimen and the result of the brake braking test. First, regarding the difference in graphite length, any of the specimens of Examples 1 to 4 has a graphite length of any measured circumference (outside surface 1, outside surface 2, inside surface 1, inside surface 2). The difference did not exceed 10 μm. On the other hand, in the test samples of Comparative Examples 1 and 2, there is a measurement circumference where the difference in graphite length exceeds 10 μm. That is, in Examples 1 to 4, the graphite length was relatively uniform within the same measurement circumference, whereas in Comparative Examples 1 and 2, the graphite length varied greatly within the same measurement circumference. .
[0041]
The average wear amount in the brake braking test was not significantly different between each example and the comparative example, but the disc thickness difference after the test showed a remarkable difference between the example and the comparative example. That is, the disk thickness difference after the test was 7 μm or less in all the test products of Examples 1 to 4, whereas the disk thickness difference after the test was 11 μm or more in the test products of Comparative Examples 1 and 2. The disk showed signs of uneven wear. According to a rule of thumb, when the disc thickness difference exceeds 10 μm, the rate of occurrence of brake vibration in an actual vehicle sharply increases. That is, in the test samples of Examples 1 to 4, the possibility of the occurrence of brake vibration due to uneven disk wear is extremely low, but in the test samples of Comparative Examples 1 and 2, the brake vibration due to uneven disk wear is small. Very likely to manifest.
[0042]
As described above, according to the casting schemes of Examples 1 to 4, the graphite length can be made relatively uniform within an arbitrary circumference on the first and second sliding surfaces of the disk rotor. The disk rotors according to the casting methods of Examples 1 to 4 have an excellent property that, although they are worn to some extent during use, uneven wear hardly occurs.
[0043]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the casting method of a sliding rotating body of this invention, the sliding rotating body whose structure (for example, graphite form) was made substantially uniform within an arbitrary circumference on the sliding rotating body surface by a relatively simple casting method. Can be cast. In particular, the casting method of the present invention does not require special materials or high energy unlike the conventional technology, and is a highly versatile technology that can be performed using ordinary materials. Is also excellent. And, the sliding rotating body made by this casting method has a feature that it is less likely to be unevenly worn than the sliding rotating body according to the conventional casting method.
[Brief description of the drawings]
FIG. 1 is a sectional view schematically showing a casting method according to a first embodiment.
2A is a plan view of a primary product obtained from a casting method according to the first embodiment, and FIG. 2B is a partial cross-sectional view of a secondary product (test sample) according to the first embodiment.
FIG. 3 is a sectional view schematically showing a casting method according to a second embodiment.
FIG. 4A is a bottom view of a primary product according to a third embodiment, and FIGS. 4B and 4C are partial schematic cross-sectional views of a casting method according to the third embodiment.
5A is a bottom view of a primary product according to a fourth embodiment, and FIGS. 5B and 5C are partial schematic cross-sectional views of a casting method according to the fourth embodiment.
6A is a plan view of a casting plan of Comparative Example 1, FIG. 6B is a plan view of a casting plan of Comparative Example 2, and FIG. 6C is a partial schematic cross-sectional view of the casting plans of Comparative Examples 1 and 2. FIG. .
FIG. 7 is a graph showing a measurement result of a wear amount of Example 2 in a brake braking test.
FIG. 8 is a graph showing a change in disk thickness of Example 2 before and after a brake braking test.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Upper mold, 2 ... Lower mold, 3 ... Core (1-3 constitutes a mold), 10 ... Weir adjacent to the outer peripheral edge of the casting molding space, 11 ... Runner located outside the weir , 12, 13, 14 ... runner, 20 ... weir adjacent to the inner peripheral edge of the casting molding space, 21 ... runner located adjacent to the inside of the weir, 22 ... tunnel runner, 23, 24, 25 ... weir, C, C1, C2: cavity (casting molding space).

Claims (5)

A method for casting a sliding rotating body having a circular outer peripheral portion or inner peripheral portion in a plan view state, using a casting molding space, a mold having a weir and a runner,
The casting molding space has an outer peripheral edge or an inner peripheral edge having a circular shape in plan view corresponding to the shape of the sliding rotating body, and a weir that communicates the casting molding space with a runner is provided in the casting molding space. Characterized in that it is installed so as to occupy 28% to 100% of the entire outer periphery or inner periphery at a position adjacent to the outer periphery or the inner periphery of the sliding rotating body. Method. The said weir is installed so that it may occupy the whole perimeter of the outer peripheral edge or the inner peripheral edge in the position adjacent to the outer peripheral edge or the inner peripheral edge of the casting molding space, The claim 1 characterized by the above-mentioned. A method for casting a sliding rotary body according to the above. A plurality of the weirs are present at positions adjacent to the outer peripheral edge or the inner peripheral edge of the casting molding space, and the plurality of weirs constitutes 28 of the entire periphery of the outer peripheral edge or the inner peripheral edge of the casting molding space. The casting method for a sliding rotary body according to claim 1, wherein the sliding rotary body is installed so as to occupy% to 100%. At a position where at least a part of the casting molding space and the weir are directly connected, the ratio of the cross-sectional area of the weir to the surface area of the entire periphery at the outer peripheral edge or the inner peripheral edge of at least a part of the casting molding space (sectional ratio) The method according to any one of claims 1 to 3, wherein the size of the weir is set so that the value of the weir is 10% to 60%. At the outer or inner adjacent position of the weir, the bottom is lower than the weir and occupies a range corresponding to 70% to 100% of the entire circumference of the outer peripheral edge or the inner peripheral edge of the casting molding space. A runner is provided, and a ratio (h1 / t) between the height (h1) of the runner and the height (t) of the weir is determined by the ratio of the outer peripheral edge or the inner peripheral edge of the casting molding space. The dimension of the runner is set so that the ratio of the runner weir (s · h1 / t) obtained by multiplying the occupancy ratio (s) of the weir to the entire circumference is 1.2 or more. A method for casting a sliding rotary body according to any one of claims 1 to 4.

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