JPS6037283B2 - rotary piston engine - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a rotary piston engine, and particularly to a rotary piston engine equipped with an oil seal having an improved lip portion. (Prior Art) In a rotary piston engine configured such that the rotor rotates planetarily in a casing surrounded by a side housing and a rotor housing, an oil seal inserted into the side surface of the rotor is shown in FIG. As shown, an iron is inserted into an oil seal groove 2 cut into the side surface of the rotor 1 so as to be able to protrude and retract freely by the spring force of a spring 3, and a lip portion 5 formed on the oil seal 4 slides on the side surface of the side housing 6. b. This is to maintain sealing performance between both sides of the motor 1 and the side housing 6. In addition, in FIG. 1, 7 is the circle formed on the oil seal 4.
This is a ◯ ring installed in the ring groove 8. Conventionally, in order to ensure the wear resistance of the oil seal 4, the lip portion 5 of the oil seal 4 has been coated with high-hardness chrome plating 9 (see Japanese Patent Publication No. 45-21641). Since sufficient wear resistance cannot be obtained, high boron and high phosphorus cast iron with high wear resistance is also used for the base material 4a constituting the oil seal 4. However, wear resistance is still not sufficient, and as a result, oil consumption is relatively high.
Ivy. The oil seal 4 is required to have the ability to follow the surface of the side housing 6, that is, the ability of the lip portion 5 of the oil seal 4 to follow changes in the unevenness of the surface of the side housing 6 during rotation of the engine. In order to obtain this followability of the oil seal 4, it is possible to improve the structure and dimensions of the oil seal and to improve the material of the oil seal, but the former improvement in structure and dimensions is mechanically It is difficult to change because of the restrictions. Therefore, improvements in the material aspect of oil seals have been considered, and while a material with high elasticity and a low Young's modulus is used as the base material of the oil seal, a high hardness material with excellent wear resistance, which is contrary to the elasticity of the base material described above, has been used. It is conceivable to use it for the lip part. For the above-mentioned purpose, the applicant previously developed a C
3.0-6. %,C. 4-12%, WI-6%, PO-
5 to 2.0%, and 6 to 43% of at least one of Mo, Nb, and Ta, the iron-based alloy containing Mo, W
Composite carbide of We proposed an oil seal for a rotary piston engine in which a chip material made of an anti-bond metal with a dispersed structure is welded (Japanese Patent Application No. 51-64292).
Special Publication No. 56-52986)). The iron base material of the oil seal proposed above has a Young's modulus of 22×1 pitch.

[9/side 2 or less, for example, ordinary steel (21 x 1 k9' ribs 2), ordinary cast iron (12 x 1 k9/side 2), iron-based sintered alloy (13 x] pkg/side 2) It is what you use. The structure of the above chip material has two characteristics. This is because at least one type of carbide among MoC, N ratio, and TaC blended into the green compact is present in the metal part (the boundary between the metal part and the composite carbide) in the Akatsuki alloy structure when the infiltration pyrography is completed. ) remains in substantially its original form, and the composite carbide crystallized or precipitated in the form of (Fe.Mo.W)mCn has a lumpy shape. This invention simultaneously satisfies the contradictory performance of minimizing the wear of the oil seal itself through the type and area ratio of the carbide in the tip portion, and at the same time, does not damage or seize the side housing surface. In particular, thanks to the good followability, the side housing surface is not damaged even if the chip material is somewhat hard, so the oil seal performance can be maintained at high performance over a long period of time. However, the above proposed invention has a problem in that the inner surface of the side housing has poor wear resistance because the side housing is made of a normal iron-based material. (Problem to be solved by the invention) A member made of iron-based material subjected to nitriding treatment has Fe on its surface.
It is well known that a compound layer made of a -C-N compound and a diffusion layer are formed below this compound layer, and that both the compound layer and the diffusion layer have high hardness and excellent wear resistance. . Therefore, when a side housing is formed from a member made of the above-mentioned iron-based material subjected to nitrocarburizing treatment, and an oil seal having a lip section made of the above-mentioned composite alloy is used for this side housing, the amount of wear of the composite alloy of the lip section is is large for the compound layer of the side housing, and small for the diffusion layer exposed after the compound layer is worn away. However, when an oil seal with a lip consisting only of a hard chrome plating layer is used for the side housing, contrary to the above composite alloy, the amount of wear of the hard chrome plating layer is smaller than that of the compound layer of the side housing. However, it increases rapidly for the diffusion layer. (Means for Solving the Problems) The present inventors continued their research on oil seals having lip portions made of the above composite alloy, and as shown in FIG. A hard chrome plating layer 9 is provided on the inner circumferential surface of the annular oil seal 4 having a sealing lip portion 5, and the tip material 10 and the hard chrome plating layer 9 simultaneously contact the 6 surfaces of the side housing which has been subjected to the European Qinization process. They learned that if they were made to slide, their wear resistance would further improve synergistically. That is, the present invention provides a rotary piston engine in which a rotor rotates planetarily in a casing surrounded by a side housing or an intermediate housing and a rotor housing. The inner surface has a compound layer made of a Fe-C-N-based compound formed by softening treatment and a diffusion layer below the compound layer,
On the other hand, the oil seal, which is removably inserted into the oil seal compound cut into the side surface of the rotor, has a C in its lip.
3 to 6.5% by weight (hereinafter abbreviated as %), Co4 to 12%,
WI~6%, PO. 5-2.0% and Mo, Nb and Ta
An iron-based alloy containing 6 to 43% of at least one of the following, wherein the composite carbide of Mo, W and Fe has an area ratio of 30
~80% crystallized or precipitated, and the area ratio of at least one carbide among MoC, N ratio, and TaC is 6~80%.
A chip material made of a sintered alloy having a dispersed structure is deposited on the metal part of the 40% iron-based alloy structure, and
This rotary piston engine is characterized in that the chip material is provided with a hard chromium plating layer so that the chip material contacts and moves simultaneously with the side housing. The iron-based material used for the side housing of this invention is subjected to soft nitriding treatment such as gas soft nitriding treatment or Tufftride.
It is an iron-based material, such as cast iron or steel, on which a Fe--C--N compound layer and a diffusion layer are formed below. Specifically, FCH-1, FCH-2, FCD-45, F
Preferably, cast iron such as CD-5, steel such as SACM1, SCR4, S5&, etc., manganese chromium steel, rust type 2, type 4, and chromium molybdenum mirror steel, type 1 and 3 are preferable. Among the above-mentioned cast irons, flake graphite iron is particularly preferable because the compound layer due to the soft nitriding treatment does not adhere firmly to the graphite on its surface, and the graphite itself also undergoes decarburization and becomes brittle and further becomes nitrided. During treatment, the cast iron matrix and graphite tend to separate due to thermal expansion and contraction, and as a result, when surface polishing is performed, part or most of the compound layer formed on the graphite surface breaks and falls off. A large hole will be formed in the area. The holes formed in this way serve as a supply base for lubricating oil on the sliding surface, improving lubricity. The depth and number of holes formed when the above-mentioned side housing is surface polished depends on the amount and form of graphite contained in the cast iron, but other treatments include soft nitriding and surface polishing. It is influenced by the conditions and degree of The soft nitriding treatment applied to the side housing is performed by a well-known method. For example, gas nitrocarburizing treatment
This is a method of heating in an atmosphere consisting of a carburizing modified gas (hydrocarbon gas) and ammonia gas for 500 to 590 ℃ and 0 to 1 to 6 hours. In addition, the tufftride method is KCN1KC
This is a method in which NO or NaCN and NaCNO are used as main ingredients, barium carbonate or sodium carbonate is added as a promoter, and the mixture is heated at 500 to 5900 C for 1 to 6 hours in a salt bath. In order to perform nitrocarburizing treatment on an iron-based material, in the case of cast iron, it is preferable to polish at least the sliding surface of the cast iron to give a predetermined surface finish before the nitrocarburizing treatment. The thickness of the compound layer and diffusion layer formed on the surface of the side housing by the soft nitriding treatment is determined by the thickness of the iron-based material,
The thickness of the compound layer is usually 7 to 10 microns, and the thickness of the diffusion layer is 200 to 30 microns, although it varies depending on the nitrocarburizing treatment conditions.
0 micron, and Pickers hardness (Hv) is 80
It is 0-1000. Next, the compositions of the chip materials will be explained individually. C is an element in the range of 3 to 6.5%, which is indispensable for producing carbides and obtaining wear resistance.If it is less than 3%, the amount of carbides produced is small, resulting in insufficient wear resistance, and the oil The decrease in sealing performance becomes noticeable. Moreover, if it exceeds 6.5%, graphite will precipitate, the flow of the metal will deteriorate, and the wear resistance will also deteriorate, which is not preferable. Co is 4
~12%, solid solution in the iron base improves the hardness of the base, and strengthens the bond between the carbide and the base to prevent carbide etc. from being lost during processing. If it is less than 4%, the effect is insufficient, and if it exceeds 12%, the metal portion becomes too large compared to the carbide, which reduces wear resistance, which is not preferable. W is an element that combines with carbon to form composite carbides at a concentration of 1 to 6% and improves wear resistance.If it is less than 1%, the effect is insufficient, and on the other hand, if it exceeds 6%, the quality deteriorates. This is undesirable as it causes defects during processing. P is 0.5 to 2% and is necessary to lower the melting point of the infiltrated metal and to improve the wettability between the infiltrated metal and the green compact. This is preferable because it improves abrasion resistance by forming scratches and imparts properties that prevent damage to the mating material. If it is less than 0.5%, the effect will be insufficient, and if it exceeds 2%, it will reduce the wear resistance of the chip material, which is not preferable. The composite carbide of Mo, W and Fe imparts wear resistance and seizure resistance to the oil seal of the present invention, and its effect is insufficient when the area ratio is 30%, and on the other hand, when it exceeds 80%. This is not preferable because it becomes brittle and causes defects during processing, and the workability is significantly deteriorated. In addition to the above-mentioned elements, V and Cr can be mixed into the iron alloy in an amount of about 10% or less and can be used without any problem. The carbides of Mo2C, NbC, and TaC have higher hardness than the composite carbides produced in the above-mentioned iron alloy, and are most effective in improving the wear resistance of the seal itself. In addition, among the many carbides that exist, Mo2C, N ratio and T
The three materials selected for aC were the superior iron alloy and the good wettability.
This is because it must also have a hardness that will not damage the side housing. If the amount of these carbides added is less than 6%, a sufficient effect of improving wear resistance cannot be obtained. Moreover, if it exceeds 40%, the total amount of carbides becomes too large and becomes brittle, leading to chipping at the tip end during machining, which is not preferable. Further, it is preferable that the total amount of the composite carbide produced in the iron alloy and the carbide added is within the range of 36 to 86% in terms of area ratio. The oil seal in this invention is produced by welding the above-mentioned chip material to the surface of an iron-based base material, and then forming the oil seal into a predetermined shape.
A hard chrome plating layer is formed on the inner peripheral surface of this annular oil seal by electrolytic plating. The thickness of the hard chromium plating layer is preferably 20 to 300 microns; if it is less than 20 microns, it is difficult to obtain the desired wear resistance, and if it exceeds 300 microns, the effect is saturated and it is economically wasteful. Hardness Hv of hard chrome plating layer is 7
It is preferable that it is 00-1000. (Function) This invention applies to a lip portion of an oil seal that is retractably inserted into an oil seal groove cut into the side surface of a rotor in a side housing or an intermediate housing whose inner surface is nitrocarburized. The welded chip material made of the above-mentioned composite alloy and the hard chrome plating layer provided on the chip material slide at the same time, and at the initial stage of sliding, the compound layer of the housing and the hard chrome plating layer slide together. Since the composite alloy has good compatibility with the layer, there is less friction at the lip part, and when the compound layer is worn away and the diffusion layer is exposed, the abrasion of the lip part can be reduced due to the good compatibility between the composite alloy and the diffusion layer. . (Example) S4 & (E = 21 x 1 pik9) as the base material of the oil seal
/ fence 2 JIS standard) on the outer diameter 127 side, inner diameter 117 side, height 6 skin ring on the top surface of the ring, width 3.5 willow, depth 1. After creating a groove for the ribs and filling the groove with iron alloy powder and carbide powder (both 150 mesh or less) having the following components at a compaction pressure of 3t/c, the
The green compact was completely fused to the base material by heating at 150 to 1160 qo for 15 minutes. This composite material was ground into a predetermined shape with a ring groove, and a hard chrome plating layer with a thickness of 0.15 mm was further provided on the inner peripheral surface of the ring. The dimensions of the obtained oil seal are outer diameter 1
It had 26 ribs, 11 inner ribs, and 5.7 fences in height. The components of the chip material are C5.0%, Co7.7%Mol. 9
%, W3.9%. Pl. 1% Nb, 18% residual Fe, and carbides of Mo, W, and Fe were precipitated in an area ratio of 40%, and the hardness Hv was 770. Further, the hardness Hv of the hard chromium plating layer is 950. As shown in FIG.
The circular velocity of the disk 6a at the pressure bale portion is set to 5.
The wear width (rib) of the lip portion was measured at 2 h/sec. Figure 4 shows the wear width of the lip portion and the test time (hours) when the material of the disc 6a is cast iron and its surface has been subjected to gas number nitriding treatment (conditions 570qo, 4 hours). This is a graph showing the relationship between the two and also includes a comparative example. The solid line (0 mark) is an example in which the thickness of the chrome plating layer was changed,
The chain line (x mark) is a comparative example using only a composite alloy, and the dotted line (△ mark) is a comparative example in which only a chrome plating layer is provided on the lip portion.
Dotted line (△ mark) A indicates the thickness of the chrome plating layer is 0.1 Yanagi,
In B, the thickness of the chromium plating layer is 0.15 mm, and the bending points a and b in A and B indicate the points where the compound layer of the disk 6a is worn away and begins to be exposed. In addition, as shown by the chain line (x), in the comparative example where the lip portion is made of only a composite alloy, the amount of wear is large due to the compound layer of the mating disc 6a, and the compound layer is worn away and the diffusion layer is exposed. Wear is also accelerated by wear particles. As can be seen from FIG. 4, the wear resistance of the present invention is synergistically improved because the chip material and the chromium plating layer come into contact with the disk surface at the same time. (Effects of the Invention) As explained above, according to the present invention, the compound layer, the diffusion layer, and the diffusion layer formed on the inner surface of the side housing or the intermediate housing by the soft nitriding treatment make the housing itself In addition to improving the abrasion resistance of the oil seal, the lip portion of the oil seal is configured so that the composite alloy and the hard chrome plating layer slide in contact with the inner surface of the housing at the same time. A hard chrome plating layer that is compatible with the compound layer improves wear resistance, and even when the compound layer wears away and the diffusion layer is exposed, the diffusion layer and the composite alloy have good compatibility, improving wear resistance. do. Therefore, it exhibits good wear resistance over a long period of time, improves the sealing performance of the oil seal, and has excellent practical effects in that oil consumption can be reduced.

[Brief explanation of the drawing]

Figure 1 is a vertical sectional view explaining the oil seal device, Figure 2 is a vertical sectional view explaining the oil seal device;
The figure is a sectional view of an oil seal according to the present invention, FIG. 3 is a front view of a method for measuring abrasion properties, and FIG. 4 is a graph of measurement results showing the relationship between abrasion width and time. 1...Lower, 2...Oil seal groove, 4...Oil seal,
5... Lip portion, 6... Side housing, 9... Hard chrome plating layer, 10... Chip material. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In a rotary piston engine configured such that a rotor rotates planetarily in a casing surrounded by a side housing or intermediate housing and a rotor housing, the inner surface of the side housing or intermediate housing is subjected to nitrocarburizing treatment. It has a compound layer made of a Fe-C-N-based compound formed by this process, and a diffusion layer below that layer, and an oil seal groove that is retractably inserted into an oil seal groove cut into the side surface of the rotor. The seal contains C3 to 6.5% by weight (
(hereinafter abbreviated as %), Co4-12%, W1-6%, P0.
5 to 2.0% and at least one of Mo, Nb and Ta
An iron-based alloy containing 6 to 43% of seeds, in which composite carbides of Mo, W and Fe are crystallized or precipitated in an area ratio of 30 to 80%, and at least one of Mo_2C, NbC and TaC. A chip material made of a sintered alloy having a structure in which carbides of 6 to 40% by area are dispersed in the metal part of an iron-based alloy structure is welded, and a chip material and a chip material are welded to the side housing. A rotary piston engine characterized by having a hard chrome plating layer so that the piston contacts and slides at the same time.