JPS6037281B2 - rotary piston engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) 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. 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 groove 5 formed on the oil seal 4 slides on the side surface of the side housing 6. In particular, the sealing performance between both sides of the rotor and the side housing 6 is maintained.

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 was coated with a high-hardness chrome plating 9 (see Japanese Patent Publication No. 45-21641), but the chrome plating 9 alone did not provide sufficient wear resistance. Material 4a was also made of highly abrasion-resistant, high-boron, high-phosphorus cast iron. Even so, the wear resistance was still not sufficient, and as a result, the amount of oil consumed was relatively large. The oil seal 4 is required to have the ability to follow the surface of the side housing 6, that is, the lip portion 5 of the oil seal 4 is required to follow changes in the unevenness, etc. 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 highly elastic and low Young's modulus material is used as the oil seal base material, a high hardness material with excellent wear resistance, which is contrary to Motomura's elasticity mentioned above, has been used. It is conceivable to use it for the lip part. For the above purpose, the present applicant previously proposed C3-6%, Co5-20%, Mol-6%, W
A chip material made of an iron-based alloy containing ~8% of I and having a structure in which composite carbides mainly composed of Mo, W, and Fe are crystallized or precipitated in an area ratio of 20 to 60% is used as a base material of an iron-based material. We have proposed an oil seal for a rotary piston engine, which is characterized by being welded to the lip of the oil seal (Tokubuta No. 51-6429 (Japanese Patent Publication No. 56-52984)). The iron base material of the oil seal proposed above has a Young's modulus of 22×1 pik9' side 2
Below, for example, ordinary steel (21 x 1 kg/side 2), ordinary cast iron (12 x 1 kg/side 2), iron-based Akatsuki alloy (13 x 1 kg/side 2),
The hardness of the chip material is within the range of Hv500 to Hv1000, and the shape of the crystallized or precipitated carbide is needle-like, and its size is Size 50-200 microns, width 10-5
Those in the range of 0 microns are obtained. The hardness of the chip material alloy and the size and area ratio of the carbide minimize the wear of the oil seal itself, while also satisfying the contradictory performance of not scratching or seizing the side housing surface. be. 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 steel material 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 portion made of the above-mentioned composite alloy is used for this side housing, wear of the composite alloy in the lip portion occurs. The amount is
It is more for the compound layer of the side housing, and less for the diffusion layer exposed when 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-mentioned composite alloy, and as shown in FIG. A hard chrome plating layer 9 is provided on the inner peripheral surface of the annular oil seal 4 having a dripping portion 5, and the chip material 10 and the hard chrome plating layer 9 simultaneously contact and slide onto the nitrocarburized side housing 6 surface. It was discovered that if this was done, the wear resistance would be further improved synergistically.

That is, the present invention provides a rotor piston engine in which a rotor is configured to rotate planetarily in a casing surrounded by a side housing or an intermediate housing and a rotor housing. has a compound layer made of Fe-C-N based compound formed by nitrocarburizing treatment and a diffusion layer below that layer, while an iron is inserted freely into the oil seal compound cut into the side surface of the rotor. The oil seal has C3 on its lip.
~6% by weight (hereinafter abbreviated as %), Co5~20%, Mol
~6%, WI ~8%, consisting of an iron-based alloy, Mo,
Composite carbide mainly composed of W and Fe with an area ratio of 20 to 60
A chip material having a crystallized or precipitated structure is deposited on the chip material, and a hard chromium plating layer is provided on the chip material so that the chip material moves simultaneously with the contact tank with respect to the side housing. It is a rotary piston engine.

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-45FC
Cast iron such as D-15 steel, steel such as SACM1, SCR4, S5, etc., manganese chrome steel grade 2, grade 4, and chrome molybdenum steel grade 1 and 3 are preferable. Among the above-mentioned cast irons, flake graphite iron is particularly preferable because the compound layer produced by soft nitriding does not adhere firmly to the graphite on its surface, and the graphite itself also undergoes decarburization and becomes brittle. During the nitriding process, the cast iron base material 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 that area. The holes thus formed serve as a supply base for lubricating oil on the marshy 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 also influenced by the conditions and degree of The nitriding treatment applied to the side housing is performed by a well-known method.

For example, gas oxynitriding treatment is performed in an atmosphere consisting of carburizing modified gas (hydrocarbon gas, etc.) and ammonia gas.
~590qo, a method of heating for 1 to 6 hours. Also,
The tufftride method uses KCN+KCNO or NaCN+
Using NaCNO as the main ingredient, barium carbonate and sodium carbonate are added as accelerators, and the mixture is heated to 500 to 590 q in a salt bath.
o, a method of heating for 1 to 6 hours. 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%, 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 a decrease in oil seal performance. becomes significant.

Moreover, if it exceeds 6%, graphite will precipitate, the flow of the metal will deteriorate, and the wear resistance will also deteriorate, which is not preferable. More preferable <is 3
．． It is 5-5%. Co is 5 to 20% and solid-solves in the iron base to improve the ballability of the base and strengthen the bond between the carbide and the base to prevent the carbide etc. from being lost during processing. .

If it is less than 5%, the effect is insufficient, and if it exceeds 20%, the metal portion becomes too large compared to the carbide, which reduces wear resistance, which is not preferable.

More preferably, it is 10 to 15%. Mo is 1-6%
It is the main element that combines with carbon to form a composite carbide that improves wear resistance.If it is less than 1%, the effect is insufficient, and if it exceeds 6%, the ballability decreases and it may break during machining. This is undesirable as it has the disadvantage of

More preferably, it is 2 to 5%. W is an element that forms composite carbides and improves wear resistance in a content of 1 to 8%, similar to Mo. If it is less than 1%, the effect is insufficient, and if it exceeds 8%, the toughness decreases. This is undesirable as it causes defects during processing.

More preferably it is 2 to 6%. The composite carbide of Mo, W and Fe imparts wear resistance and seizure resistance to the oil seal of the present invention, and the effect is insufficient when the area ratio is 20%, and on the other hand, when it exceeds 60%. This is not preferable because it becomes brittle and causes defects during processing, and the workability is significantly deteriorated.

More preferably, it is 25 to 50%. If P is added in addition to the above-mentioned elements by 4% or less, preferably 1 to 3%,
It lowers the melting point when welding the chip material to the oil seal base material, making the welding process easier, and it also crystallizes Steadite, which reduces damage to the mating material and improves workability. preferable. Further, even if 10% or less of V or Cr is mixed in, it can be used without any problem in terms of performance. The oil seal in this invention is produced by welding the above-mentioned chip material onto the surface of an iron base material, then molding it into a predetermined shape and size, and plating the inner peripheral surface of this annular oil seal with hard chrome by electrolytic plating. It is made up of layers.

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 provides a lip portion of an oil seal that is retractably inserted into a side housing or an intermediate housing whose inner surface is nitrocarburized, and is retractably inserted into an oil seal structure that faces the side surface of a rotor. The deposited chip material made of the above-mentioned composite alloy and the hard chrome plating layer provided on the chip material come into contact and slide at the same time, and at the initial stage of sliding, the compatibility between the compound layer of the housing and the hard chrome plating layer is high. Since the friction is good, there is little friction on the lip part, and on the other hand, when the compound layer is worn away and the diffusion layer is exposed, the composite alloy and the diffusion layer have good compatibility, so the wear on the lip part can be reduced.

(Example) S4 & (E = 21 x 1 pi k9
/ willow 2 JIS standard) outer diameter 127 side, inner diameter 117 skin, height 6 skin The upper surface of the ring has a width of 3.5 ribs and a depth of 1. After creating a groove for the enemy and filling this site with iron alloy powder and carbide powder (both 150 mesh or less) having the following components at a compaction pressure of 3 tons, it was heated to 115 mm in a non-oxidizing atmosphere.
The green compact was completely fused to the base material by heating at 0 to 1160 oo for 15 minutes.

This composite material was ground into a predetermined shape having 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 was 26 cm long, had an inner diameter of 11 kalpas, and had a height of 5.7 cm. The components of the above chip material are C4.5%, Col3.0%, Mo3
．． 0%, W5.0%, P2.0%, Cr2.5%, V2
．． 5 Fe residue, and the amount of composite carbide (Fe, Mo, W) precipitated in the alloy formed by settling this was about 38% in terms of area ratio, and its hardness Hv was 720. Further, the hardness Hv of the hard chromium plating layer is 950. As shown in FIG.
．． The abrasion width (ca) of the lip portion was measured by applying pressure of 5 kg and setting the circular speed of the disk 6a at the pressure saddle portion to 5.2 h/sec. Figure 4 shows the wear width of the lip portion and the test time (hours) when the disc 6a is made of cast iron and its surface is subjected to gas nitrocarburizing treatment (condition 57000, 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.
The dotted line (△ mark) A indicates the thickness of the chrome plating layer by 0.1 rib,
B shows the thickness of the chrome plating layer on the 0.15 side, and the bending points a and b in A and B indicate the point where the compound layer of the disk 6a is worn away and the diffusion layer begins to be exposed. . Also, the chain line (
As shown in ( Wear is accelerated by As can be seen from FIG. 4 above, in the present invention, the chip material and the chrome plating layer simultaneously slide in contact with the disk surface, thereby synergistically improving the wear resistance.

(Effects of the Invention) As explained above, according to the present invention, the compound layer and the diffusion layer formed by the nitrocarburizing treatment on the inner surface of the side housing or intermediate housing improve the wear resistance of the housing itself. At the same time, the oil seal slip part is constructed 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, so at the initial stage of sliding, the compound layer of the housing The hard chromium plating layer, which is compatible with the composite alloy, improves wear resistance, and even when the compound layer is worn away and the diffusion layer is exposed, the diffusion layer and the composite alloy are compatible, so the wear resistance is improved.

Therefore, it exhibits 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 drawings]

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... Rotor, 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 3

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 3 to 9% by weight of C (hereinafter abbreviated as %), 5 to 20% of Co, 1 to 6% of Mo, and 1 to 6% of W in its lip.
It consists of an iron-based alloy containing 8% Mo, W and Fe.
A chip material having a structure in which composite carbide is mainly crystallized or precipitated in an area ratio of 20 to 60% is welded, and the chip material is plated with hard chrome so that the chip material slides into contact with the side housing at the same time. A rotary piston engine characterized by having layers.