JPH06595Y2 - Side housing structure of multi-cylinder rotary piston engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a multi-cylinder rotary piston engine,
The present invention relates to a side housing structure in which a side end portion of a housing inner space in which a rotor is arranged is formed and a cooling water passage, an oil passage, and the like are formed therein.

(Prior Art) In a two-cylinder rotary piston engine that is generally used in automobiles and the like, usually, a rotor is rotatably supported by two eccentric portions provided on an eccentric shaft, and the rotor is rotatably supported on both sides of the rotor. A bearing portion for supporting the eccentric shaft is provided on each of the front side and rear side housings located. In such a rotary piston engine, since the bearing is not provided between the two rotors, the centrifugal force generated by the balance weight or the like attached to one end of the rotor or the eccentric shaft is not generated during engine operation. Due to the action, especially at high rotation, the eccentric shaft undergoes relatively large deflection, and the fixed gear attached to the side housing, the internal gear attached to the rotor and meshed with the fixed gear, and the side housing are provided. Since the bearings and the like are subject to unbalanced loads, their life is shortened, and the rotor is tilted from the normal posture, so that side housings or 2
There is a possibility that a side housing (hereinafter referred to as an intermediate housing) arranged between two rotors may be seized.

As one measure for preventing such a problem from occurring, it is considered that a bearing portion that supports a portion of the eccentric shaft between the two eccentric portions is newly provided in the intermediate housing. . When such a measure is adopted, in assembling the engine body, the bearing portion provided in the intermediate housing needs to have a relatively large outer diameter that allows the eccentric portion to pass therethrough.

However, when a bearing portion having a relatively large outer diameter is provided in the intermediate housing, a blow-by gas passage, an oil passage, which should be formed inside the intermediate housing,
The effective passage cross-sectional areas such as the oil return passage and the cooling water passage will be significantly reduced, and the flowability of blow-by gas, lubricating oil and cooling water flowing through these passages will deteriorate. become.

Therefore, in order not to cause such a situation,
The applicant of the present application has previously described, for example, Japanese Patent Application No. 62-102.
As also shown in No. 927, the eccentric shaft is assembled by fitting the two eccentric shaft members provided with the eccentric portion supporting the rotor, and the fitting for fitting the two eccentric shaft members. A rotary piston engine is proposed in which the parts are supported by a bearing part formed in the intermediate housing.

The bearing portion provided on the eccentric shaft and the intermediate housing in the proposed rotary piston engine is specifically configured, for example, as shown in FIG.

That is, the eccentric shaft 70 is positioned on the eccentric portion 71a that supports the rear rotor 73, and on the front side of the eccentric portion 71a.
Small diameter portion 71b and eccentric portion 71a having a relatively small diameter
And a small-diameter portion 71b, and a main eccentric shaft member 71 provided with a taper shaft portion 71c whose outer diameter increases toward the eccentric portion 71a side, and an eccentric portion that supports the front rotor 74. 72a, a small diameter cylindrical portion 72b located on the inner peripheral side of the eccentric portion 72a, into which the small diameter portion 71b of the main eccentric shaft member 71 is inserted, and a rear side of the small diameter cylindrical portion 72b, and the main eccentric shaft 72b. Tapered shaft portion 71 of member 71
Although not shown in FIG. 3, the main eccentric shaft member 71 and the sub eccentric shaft member 72 include a key and the like. This prevents relative displacement in the rotational direction.

When assembling the main eccentric shaft member 71 and the sub-eccentric shaft member 72, the main eccentric shaft member 71 is inserted from the rear side into the bearing portion 83 of the intermediate housing 80 by an appropriate means,
The sub eccentric shaft member 72 has the intermediate housing 80
Of the main eccentric shaft member 71 and the taper hole forming portion 72c of the sub-eccentric shaft member 72 are fitted to each other, whereby the sub-eccentric shaft member 71 with respect to the main eccentric shaft member 71 is inserted. The positioning of 72 in the axial direction is performed. The rear end of the main eccentric shaft member 71 is supported by a bearing portion provided on the rear side housing, and the portion of the auxiliary eccentric shaft member 72 that is closer to the front side than the eccentric portion 72a is the front side. The tapered hole forming portion 72c of the auxiliary eccentric shaft member 72 is supported by a bearing portion provided in the housing.
The outer peripheral surface portion of is supported by a bearing portion 83 provided in the intermediate housing 80.

In the rotary piston engine having such a configuration, in addition to the bearing portions provided on the rear side housing and the front side housing, respectively, the tapered hole forming portion located between the two eccentric portions 71a and 72a of the eccentric shaft 70 is formed. 72
Since the bearing portion 83 that supports the outer peripheral surface portion of c is provided in the intermediate housing 80, the deflection of the eccentric shaft 70 is suppressed,
The fixed gear, the internal gear, the bearing, etc. are prevented from receiving an eccentric load so much that their lifespan is extended, and the rear rotor 73 and the front rotor 74 are less likely to tilt from their normal postures. The occurrence of a situation in which it burns into the side housing or the like is prevented.

Further, the eccentric shaft 70 is of a split type composed of a main eccentric shaft member 71 and a sub eccentric shaft member 72, and when the eccentric shaft 70 is assembled to an engine, the main eccentric shaft member 71 and the sub eccentric shaft member 71 are attached. Since the shaft member 72 is engaged with the shaft member 72, the bearing portion 83 provided in the intermediate housing 80 is provided.
Of the blow-by gas passage, the oil passage, the oil return passage, and the cooling water passage, which are to be formed inside the intermediate housing 80, are sufficiently large. It becomes possible to

Generally, in a rotary piston engine, for example, as disclosed in Japanese Utility Model Laid-Open No. 59-165933, there are oil passages between the eccentric shaft and the rotor and between the bearing portion and the eccentric shaft. Oil for lubrication is supplied, and oil provided for lubrication between the eccentric shaft and the rotor and between the bearing portion and the eccentric shaft and the eccentric shaft are provided in the oil return passage. The oil used for cooling the inside of the rotor is returned through the oil passage, and the oil is returned to the oil pan arranged below the side housing. A blow-by gas passage that connects the oil pan and the outlet formed in the upper portion of the side housing is provided in one of the portions of the side housing that are located on both sides of the bearing portion. It surrounds and communicates with the blow-by gas passage, and also communicates with the oil pan through an outlet provided at the lower end of the other side portion of the bearing portion of the side housing.

In the rotary piston engine with the side housing having the structure as described above, the liquid level of the oil in the oil pan fluctuates when the vehicle equipped with the side piston travels on a slope or at high speed. When the lower end portion of the blow-by gas passage is blocked by oil, the blow-by gas is discharged to the outside through the oil return passage, so that the blow-by gas suppresses the deterioration of the oil. .

(Problems to be Solved by the Invention) In the rotary piston engine in which the bearing portion is provided in the intermediate housing as described above, it is necessary to supply lubricating oil to the bearing portion provided in the intermediate housing as well. Occurs, the oil to be returned to the oil pan through the oil return passage provided in the intermediate housing is increased by the amount supplied to the bearing portion. Even if the amount of oil is increased, as described above, when the number of outlets to the oil pan in the oil return passage is one, there is a possibility that the oil that should be returned to the oil will not be promptly returned. . Further, if such a single outlet is provided, there is a risk that the outlet of the oil return passage will be blocked by the oil due to fluctuations in the oil level in the oil pan, and the oil will not be returned to the oil pan. In this way, if the situation in which the oil is not properly returned to the oil pan is mimicked, the oil retained in the return passage may be excessively heated by the combustion heat depending on the arrangement of the oil return passage in the intermediate housing. As a result, the oil deteriorates, the circulation of the oil in the engine is hindered, and the cooling performance of the engine deteriorates.

In view of such a point, the present invention includes a first side housing, a second side housing and an intermediate housing,
The intermediate housing is provided with a bearing portion that supports the outer peripheral surface portion of the tapered hole forming portion that is the fitting portion of the split type eccentric shaft, and it is assumed that the amount of oil to be returned to the oil pan is increased. Also, the oil is quickly returned to the oil pan through the oil return passage, and even if the liquid level of the oil in the oil pan fluctuates and the outlet of the oil return passage is blocked,
To provide a side housing structure of a multi-cylinder rotary piston engine capable of reliably returning lubricating and cooling oil to an oil pan and discharging blow-by gas in the oil pan to the outside. With the goal.

(Means for Solving the Problems) In order to achieve the above object, a side housing structure of a multi-cylinder rotary piston engine according to the present invention supports a first rotor arranged in a first housing internal space. The main eccentric shaft member is provided with the first eccentric portion, and the tapered eccentric portion is provided with the outer diameter increasing toward the first eccentric portion, and the main eccentric shaft member is arranged in the second housing internal space. A second eccentric portion that supports the second rotor is provided, and one end of an eccentric shaft that is a tubular sub-eccentric shaft member that is provided with a tapered hole forming portion that fits into the tapered shaft portion is supported. A first side housing provided with a first bearing portion and forming a side end portion of the first housing internal space; and a second bearing portion provided with a second bearing portion supporting the other end side of the eccentric shaft. Of the inner space of the housing An intermediate housing that partitions the first housing internal space and the second housing internal space, in which a second side housing that forms an end portion and a third bearing portion that supports the tapered hole forming portion in the eccentric shaft are provided And an oil passage communicating with the third bearing portion, an oil pan disposed below the intermediate housing, and an outlet provided at an upper portion of the intermediate housing. Enclosing the blow-by gas passage and the third bearing portion,
An oil return passage communicating with the blow-by gas passage and communicating with an oil pan through first and second outlets formed at lower end portions on both sides of the third bearing portion of the intermediate housing is provided. .

(Operation) In the side housing structure of the multi-cylinder rotary piston engine according to the present invention configured as described above,
The first and second side housings are provided with first and second bearing portions that support one end portion and the other end portion side of the eccentric shaft, and in addition, the first and second bearing portions are provided on the eccentric shaft. And the third bearing portion that supports the outer peripheral surface portion of the tapered hole forming portion that is located between the second eccentric portion and the intermediate housing is provided. Therefore, it is possible to prevent the eccentric shaft from bending and the like. It is possible to prevent the portion and the like from being subjected to an unbalanced load, and also to make it difficult for the rotor to tilt from the normal posture.
Further, since the eccentric shaft is formed by being fitted to the main eccentric shaft member and the sub-eccentric shaft member, the outer diameter of the third bearing portion provided in the intermediate housing can be made relatively small. The passage cross-sectional areas of the oil passage, the oil return passage, and the blow-by gas passage formed in the housing are sufficiently large.

An oil return passage formed in the intermediate housing surrounds the third bearing portion, and the oil pan is provided via first and second outlets formed at lower end portions on both sides of the third bearing portion. Since the third bearing portion is provided, even if the amount of oil to be returned to the oil pan is increased, the oil is quickly returned to the oil pan, and the oil in the oil pan Even if the liquid level of the oil fluctuates and one of the outlets is closed, the oil is returned to the oil pan through the other outlet. By doing so, the circulation of the oil in the engine is not hindered, the oil is excessively heated by the combustion heat, and the oil deteriorates or the cooling performance of the engine deteriorates. The situation is avoided.

Further, since the oil return passage is communicated with the blow-by gas passage, the blow-by gas is discharged to the outside through the oil return passage even when the lower end of the blow-by gas passage is closed by oil. Further, the oil return passage communicates with the first and second outlets formed at the lower ends of both sides of the third bearing portion of the intermediate housing, which are kept at a relatively low temperature. Is prevented from being overheated by the heat of combustion.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a side housing structure of a multi-cylinder rotary piston engine according to the present invention, together with a two-cylinder rotary piston engine to which it is applied.

In FIG. 1, an engine body 10 includes two rotor housings 1 and 13 having trochoidal inner peripheral surfaces, and front and rear side housings 14 and 16 arranged on both sides of the rotor housings 12 and 13, respectively. And an intermediate housing 15 disposed between the rotor housings 12 and 13. These rotor housings 12 and 13, side housings 14 and 16,
And 2 formed by being surrounded by the intermediate housing 15.
The front side rotor 17 and the rear side rotor 18, which are rotatably supported by eccentric shafts 20, respectively, in the two internal spaces, have an apex seal 19 mounted at their apexes
Are arranged in contact with the trochoidal inner peripheral surfaces of the rotor housings 12 and 13. An internal gear 25 that meshes with a fixed gear 24 attached to the side housings 14 and 16 is attached to the front rotor 17 and the rear rotor 18 by a plurality of spring pins 35, and a corner seal 26, Seals such as the side seal 27 and the oil seal 28 are attached.

The eccentric shaft 20 is composed of a main eccentric shaft member 21 extending through the side housings 14 and 16 described above, and a tubular auxiliary eccentric shaft member 22 into which a part of the main eccentric shaft member 21 is inserted. . The main eccentric shaft member 21 is an eccentric portion 21a that supports the rear rotor 18, a straight shaft-shaped small-diameter portion 21b that is located on the front side of the eccentric portion 21a, and has a relatively small diameter, and the eccentric portion 21a and the small-diameter portion. 21b, and a tapered shaft portion 21c having an outer diameter increased toward the eccentric portion 21a.
And both ends of the side housing 1
It is made to project outward from 4 and 16. And
At the front side protruding portion of the main eccentric shaft member 21,
Balance weight 41, sprocket wheel 42 for driving the oil pump, distributor drive gear 43,
The V-belt pulley group 44 and the like are attached via the key 40, and a screw portion 46 into which a nut 45 for fitting and fixing is screwed is formed at the tip end portion, and the rear side protruding portion is formed. A flywheel 47 is attached. A portion of the main eccentric shaft member 21 between the eccentric portion 21a and the projecting portion to which the flywheel 47 is attached is supported by a bearing portion 32 made of bearing metal provided in the side housing 16.

Further, inside the main eccentric shaft member 21, the front side rotor 17 and the rear side rotor 18 are lubricated between the eccentric portions 21a and 22a, and the insides of the front side rotor 17 and the rear side rotor 18 are cooled. An oil passage 23 for forming the oil jet 3 is formed inside the front rotor 17 and the rear rotor 18 from the oil passage 23.
Via the front rotor 17 and the rear rotor 1
Oil for cooling is supplied to 8.

On the other hand, the sub-eccentric shaft member 22 is located on the eccentric portion 22a that supports the front rotor 17, and on the inner peripheral side of the eccentric portion 22a.
A small-diameter cylindrical portion 22b into which the small-diameter portion 21b of the main eccentric shaft member 21 is inserted, and a taper hole forming portion 22c located on the rear side of the eccentric portion 22a and into which the taper shaft portion 21c of the main eccentric shaft member 21 is inserted. It is supposed to have. The front end of the sub-eccentric shaft member 22 is supported by a bearing portion 31 made of bearing metal provided in the side housing 14. In addition, the sub-eccentric shaft member 2
The outer peripheral surface portion of the tapered hole forming portion 22c in No. 2 is a bearing portion 33 made of bearing metal provided in the intermediate housing 15.
It is supported by.

The main eccentric shaft member 21 and the sub-eccentric shaft member 22 having the above-described configurations are interposed between the small-diameter portion 21b of the main eccentric shaft member 21 and the small-diameter cylindrical portion 22b of the sub-eccentric shaft member 22. Relative displacement in the rotation direction is prevented by the nut 45, and the nut 45 is screwed into the screw portion 46 formed at the front end of the main eccentric shaft member 21, whereby the V belt pulley group 44, the distributor drive gear 43, The sprocket wheel 42, the balance weight 41, etc. are pushed to the rear side, and the auxiliary eccentric shaft member 22 is pushed to the rear side accordingly. As a result, the tapered hole forming portion 22c of the sub eccentric shaft member 22 is fitted to the taper shaft 21c of the main eccentric shaft member 21, and the sub eccentric shaft member 22 is axially positioned with respect to the main eccentric shaft member 21. With side housing 14
The eccentric shaft 20 is positioned with respect to the shafts 16 and 16 and the intermediate housing 15.

An oil pan 55 is arranged below each of the housings 12 to 16, and an oil pump 56 is attached to a side end surface portion of the side housing 14. Inside the oil pan 55, the oil strainer 5 provided at the tip of the suction pipe 57 extending from the oil pump 56.
9 is stored in the oil in the oil pan 55,
Each housing 1 is sucked out by the oil pump 56.
2 to 16 are used for lubrication of various parts of the engine through an oil passage 52 provided in the eccentric shaft 20, and an oil jet 38 that is connected to the oil passage 23. It is used for cooling the side rotor 18. Further, in each of the housings 12 to 16, a cooling water passage 51 is provided in a predetermined manner in addition to the oil passage 52.

Then, in the intermediate housing 15 among the housings 12 to 16, as shown in FIG. 2 in a cross section taken along line II-II in FIG. 1, a blow-by gas passage 58, an oil return passage 60, a cooling water passage 51. The blow-by gas generated in the oil pan 55 passes through the blow-by gas passage 58 arranged at one side of the intermediate housing 15, and the opening 64 and the opening 64 are provided at the upper portion of the blow-by gas passage 58. For example, it is guided to the intake system of the engine through a filler pipe 66 connected to 64 and a blow-by gas discharge pipe 67 connected to the filler pipe 66. At the top of the blow-by gas passage 58, an opening 64 is formed.
Besides, an opening 68, which is required in the manufacturing process and closed by a blind plug 69 after manufacturing, is provided, and a hole 65 into which an oil level gauge is inserted is also provided. One side portion of the intermediate housing 15 thus configured corresponds to a portion of the rotor housings 12 and 13 where the spark plug 71 is disposed.

The oil return passage 60 is formed by a rib portion 63 arranged so as to surround the bearing portion 33, and the oil return passage 60 is formed between the bearing metal forming the bearing portion 33 and the sub-eccentric shaft member 22. Between the front rotor 17 and the eccentric portion 22a, and between the rear rotor 18 and the eccentric portion 2
1a is a passage for returning to the oil pan 55 the oil used for lubrication and the oil used for cooling the inside of the front and rear rotors 17 and 18, and the upper end thereof is a blow-by gas. An outlet 61 is formed which is communicated with the passage 58, a portion below the bearing portion 33 is bifurcated, and is sandwiched by the cooling water passages 51 at lower ends on both sides of the bearing portion 33 of the intermediate housing 15. And the oil pan 55 through the outlet 62. The first outlet 61 is arranged so as to merge with the lower end of the blow-by gas passage 58.
The second outlet 62 is located below the exhaust port 72 provided in each of the rotor housings 12 and 13. Further, the cooling water passage 51 is
The oil passage 52, which is arranged so as to surround the oil return passage 60 and guides the lubricating oil to the bearing portion 33, is arranged in the central portion of the oil pan 55 when viewed in the thickness direction.

Under the configuration as described above, in addition to the eccentric shaft 20 being supported by the bearing portions 31 and 32 provided in the side housings 14 and 16, the intermediate housing 1
Since it is also supported by the bearing portion 33 provided in 5,
Fixed gear 2 provided on the side housings 14 and 16
4, the internal gear 25 provided on the front rotor 17 and the rear rotor 18 respectively, which meshes with the fixed gear 24, and the bearing portions 31 to 33 are prevented from being subjected to an unbalanced load, and their life is extended. At the same time, the front side rotor 17 and the rear side rotor 18 are not easily tilted from their normal postures, and they are not easily tilted.
The situation of being burned into is avoided. Also, the eccentric shaft 2
0 is a split type having a main eccentric shaft member 21 and a sub-eccentric shaft member 22, so that the outer diameter of the bearing portion 33 provided in the intermediate housing 15 is relatively small. The eccentric shaft 20 can be easily assembled to the engine body 10. Therefore, the passage cross-sectional areas of the cooling water passage 51, the oil passage 52, the oil return passage 53, the blow-by gas passage, etc. formed inside the intermediate housing 15 can be made sufficiently large.

The blow-by gas passage 5 is provided in the intermediate housing 15.
8 is provided, and the upper end portion of the oil return passage 60 surrounding the bearing portion 33 has a blow-by gas passage 58.
Both ends of the oil return passage 60 are communicated with the oil pan 55 through the outlets 61 and 62 formed at the lower ends on both sides of the bearing portion 33 of the intermediate housing 15, respectively. Therefore, in order to lubricate the bearing portion 33 provided in the intermediate housing 15,
Even if the amount of oil returned to the oil pan 55 through the oil return passage 60 is increased, the oil returned to the oil return passage 60 is promptly returned to the oil pan 55 via the two outlets 61 and 62 and burned. The heat prevents the oil from being excessively heated and deteriorated.

Further, for example, when the liquid level of the oil in the oil pan 55 fluctuates as shown by the alternate long and short dash line in FIG. 2 and the lower ends of the outflow port 61 and the blow-by gas passage 58 are blocked by the oil, From the bearing 33 and the front and rear rotors 17 and 18 to the oil return passage 6
The oil returned to 0 is returned to the oil pan 55 through the outflow port 62, and the blow-by gas generated in the oil pan 55 is discharged to the outside through the oil return passage 60 from the outflow port 62. Further, the oil return passage 6
0 is formed so as to be surrounded by the cooling water passage 51, and the outlets 61 and 62 are provided at the lower ends of both sides of the bearing portion 33 of the intermediate housing 15 and sandwiched by the cooling water passage 51. With this structure, the oil returned to the oil pan 55 through the oil return passage 60 is prevented from being excessively heated.

In the above example, the case where the invention is applied to the two-cylinder rotary piston engine has been described, but the invention is not limited thereto, and the invention can be similarly applied to a rotary piston engine having three or more cylinders.

(Effects of the Invention) As is apparent from the above description, according to the side housing structure of the multi-cylinder rotary piston engine according to the present invention, the first and second parts for supporting the rear end and the front part of the eccentric shaft are respectively provided. In addition to providing the second bearing portion, the third bearing portion that supports the outer peripheral surface portion of the tapered hole forming portion that is located between the two eccentric portions of the eccentric shaft is provided, so that the eccentric shaft bends. It is possible to prevent the bearings and the like from being subjected to an unbalanced load and shorten their lifespan, and also to prevent the rotor from tilting from its normal posture. As a result, it is possible to avoid a situation in which the side housing or the like is seized. Further, since the eccentric shaft is composed of the main eccentric shaft member and the sub-eccentric shaft member, the outer diameter of the third bearing portion provided in the intermediate housing can be made relatively small, and therefore the intermediate housing can be The passage cross-sectional areas of the formed cooling water passage, oil passage, oil return passage, blow-by gas passage, etc. can be made sufficiently large.

In addition, since the intermediate housing is provided with the two outlets of the oil return passage, even if the third bearing portion of the intermediate housing is provided to increase the amount of oil returned to the oil return passage The oil is quickly returned to the oil pan through the outlet of the oil, and therefore, it is possible to prevent the oil from being excessively heated and deteriorated by the heat of combustion. Further, since the outlets are respectively provided at the lower end portions on both sides of the bearing portion of the intermediate housing, even if one of the outlets is closed due to the fluctuation of the liquid level of the oil in the oil pan, the other outlet is provided via the other outlet. Oil can be efficiently returned to the oil pan. In the intermediate housing,
The oil return passage is formed so as to be surrounded by the cooling water passage, and the outlets are provided at the portions of the intermediate housing where the temperature is relatively low, so that the oil returned to the oil pan is excessively heated. You can avoid that.

[Brief description of drawings]

FIG. 1 shows an example of a side housing structure of a multi-cylinder rotary piston engine according to the present invention.
FIG. 2 is a sectional view showing a cylinder rotary piston engine, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. 3 is a sectional view showing a main part of a conventional rotary piston engine. In the figure, 10 is an engine body, 14 and 16 are side housings, 15 is an intermediate housing, 17 is a front rotor, 18 is a rear rotor, 20 is an eccentric shaft, 21 is a main eccentric shaft member, and 22 is a sub-eccentric shaft member. , 24 is a fixed gear, 25 is an internal gear, 31 to 33 are bearings, 51 is a cooling water passage, 5
2 is an oil passage, 55 is an oil pan, 58 is a blow-by gas passage, 60 is an oil return passage, and 61 and 62 are outlets.

Claims (1)

[Scope of utility model registration request] 1. A first housing disposed in an inner space of a first housing.
A main eccentric shaft member provided with a first eccentric part for supporting the rotor and a taper shaft part having an outer diameter increasing toward the first eccentric part, and a second housing. A second supporting a second rotor arranged in the internal space
And an eccentric part, and a first bearing part for supporting one end of an eccentric shaft formed of a cylindrical sub-eccentric shaft member provided with a tapered hole forming part that fits into the tapered shaft part. A second side housing provided with a first side housing forming a side end of the first housing internal space, and a second bearing portion supporting one end of the eccentric shaft; The interior of the intermediate housing includes an intermediate housing that partitions the first housing internal space and the second housing internal space, in which a third bearing portion that supports the tapered hole forming portion of the eccentric shaft is provided. And a blow-by connecting an oil passage communicating with the third bearing portion, an oil pan arranged below the intermediate housing and an outlet provided at an upper portion of the intermediate housing. Scan path, and surrounds the third bearing portion, together with leading to the blow-by gas passage,
A multi-cylinder having an oil return passage communicating with the oil pan through first and second outflow ports respectively formed at lower end portions on both sides of the third bearing portion of the intermediate housing. Side housing structure of rotary piston engine.