Oil storing device and engine having the same

An oil storing device includes a body portion. The body portion is formed at its one end with an engaging portion having an oil supply port for supplying engine oil and an oil return port for introducing the engine oil. The engaging portion is detachably connected to a connecting portion of a crankcase. Oil storing chambers for storing the engine oil are formed in the body portion so as to be connected to the oil supply port and the oil return port. When the engaging portion is engaged with the connecting portion of the crankcase, the oil supply port is connected to an inlet port leading to an oil pump, and the oil return port is connected to an outlet port to the crankcase.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 USC 119 to Japanese Patent Application No. 2010-073445 filed on Mar. 26, 2010 the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a storing structure for oil for lubrication of engine parts. More particularly, to an oil storing device suitable for oil drainage and an engine having the oil storing device.

2. Description of Background Art

In a crankcase structure of an engine to be mounted on a vehicle such as an automobile is known wherein an oil pan for storing engine oil is located below a crankshaft. The engine oil stored in the oil pan is supplied to a crankshaft system and a cam system to lubricate the required sliding parts. Thereafter, the oil is next circulated to be returned to the oil pan. See, for example, Japanese Patent Laid-open No. 2006-183516.

Usually, the height of the crankshaft, the capacity of the oil pan, the amount of engine oil, etc. are suitably set so that the oil level of the engine oil in the oil pan is lower than the lowermost end of a locus of rotation of the crankshaft system.

In Japanese Patent Laid-open No. 2000-328921, a dry sump lubrication device for an engine is described with a dedicated oil tank. In this dry sump lubrication device, the oil tank is connected through any means such as a pipe to a lower portion of the engine. A dedicated drain bolt is provided at the lower portion of the engine, and the oil tank is also provided with a drain bolt. In supplying oil into the engine, the oil is directly poured into the oil tank.

In the structure disclosed in Japanese Patent Laid-open No. 2006-183516, the dedicated oil pan must be provided and it has a structure of almost covering the lower portion of the engine. In draining the oil, an oil receptacle is preliminarily set below a dedicated drain bolt, and the drain bolt is next removed. In this oil draining operation, a special tool for removing the drain bolt is required and attention must be paid so as not to drop the drain bolt into the oil receptacle. Thus, this oil draining operation is troublesome. Naturally, a work space for this operation is required and waste oil disposal after draining the oil is also required. Further, in this oil draining operation, the work space, the engine itself, and the operator are soiled with the oil in most cases.

Further, an oil filler port must be provided separately as is well known in the art. More specifically, from the viewpoint of the engine structure, the oil filler port is separate from an oil drain port, and it is presently impossible to eliminate these ports and thereby reduce the number of parts detachably mounted to the engine.

In the structure disclosed in Japanese Patent Laid-open No. 2000-328921, the position of an oil pan can be changed by adopting the dry sump lubrication. Accordingly, as compared with the structure disclosed in Japanese Patent Laid-open No. 2006-183516, the workability in the oil draining operation appears to be improved. However, the number of man-hours of the oil draining operation in the structure disclosed in Japanese Patent Laid-open No. 2000-328921 is the same as that in the structure disclosed in Japanese Patent Laid-open No. 2006-183516. More specifically, a special tool is required in draining the oil. Further, any work space accepted to be soiled with the oil is required and the problem that the operator is soiled with the oil still remains.

SUMMARY AND OBJECTS OF THE INVENTION

It is accordingly an object of an embodiment of the present invention to provide an oil storing device which can make the oil draining operation very simple and can eliminate the problem of oil soiling and also to provide an engine having this oil storing device.

In accordance with the an embodiment of the present invention, there is provided an oil storing device having a body portion, wherein the body portion is formed at its one end with an engaging portion having an oil supply port for supplying engine oil to an engine and an oil return port for introducing the engine oil from the engine, the engaging portion is adapted to be detachably connected to a connecting portion of a crankcase. An oil storing chamber for storing the engine oil is formed in the body portion so as to be connected to the oil supply port and the oil return port. When the engaging portion is engaged with the connecting portion of the crankcase, the oil supply port is connected to an inlet port leading to an oil pump, and the oil return port is connected to an outlet port of an engine oil from the crankcase.

According to an embodiment of the present invention, the engaging portion is provided with closing means for closing the oil supply port and the oil return port, so that the oil storing chamber can be enclosed.

According to an embodiment of the present invention, the closing means includes a piston member for closing a communication hole to which the oil supply port and the oil return port open, a seal member for sealing the outer circumference of the piston member, and a spring member for biasing the piston member to a closed position of the communication hole. When the piston member is pushed against a biasing force of the spring member, the communication hole is opened.

According to an embodiment of the present invention, an engine oil is preliminarily sealed in the oil storing chamber.

According to an embodiment of the present invention, the piston member is provided with a grip for use in pulling the piston member out of the engaging portion.

According to an embodiment of the present invention, the oil storing chamber is formed with an opening portion adapted to communicate with the outside of the oil storing chamber.

According to an embodiment of the present invention, an oil filter is mounted to the opening portion so as to communicate with the oil storing chamber.

According to an embodiment of the present invention, a cap is mounted to the opening portion so as to communicate with the oil storing chamber.

According to an embodiment of the present invention, a cooling fin is formed on the outer surface of the body portion.

According to an embodiment of the present invention, the body portion is provided with an inspection window for visual inspection of an oil level in the body portion.

According to an embodiment of the present invention, a fastening member for maintaining an engaged condition of the connecting portion and the engaging portion is provided at one end of the body portion.

According to an embodiment of the present invention, there is provided an engine having the oil storing device.

According to an embodiment of the present invention, the connecting portion is provided at a lower portion of the crankcase, and the inlet port connected to the oil supply port is formed integrally with the outlet port connected to the oil return port.

According to an embodiment of the present invention, the connecting portion projects downwardly from a lowermost portion of the crankcase, and the oil storing device is mounted on the crankcase so that the oil storing chamber is located below the crankcase.

According to an embodiment of the present invention, when the engaging portion is engaged with the connecting portion, the piston member is pushed by the connecting portion against the biasing force of the spring member into the oil storing device, so that the oil supply port is connected to the inlet port and the oil return port is connected to the outlet port of the engine oil from the crankcase.

According to an embodiment of the present invention, when the engaging portion of the oil storing device is engaged with the connecting portion of the crankcase, the oil supply port is connected to the inlet port leading to the oil pump, and the oil return port is connected to the outlet port leading to the bottom surface of the crankcase. Accordingly, by demounting the oil storing device from the engine, the engine oil stored in the oil storing device can be discarded at a time, so that the oil changing operation can be performed cleanly and easily.

According to an embodiment of the present invention, the engaging portion is provided with the closing means for closing the oil supply port and the oil return port. Accordingly, the oil storing chamber is enclosed before the oil storing device is mounted to the engine, so that the entry of dust into the oil storing chamber can be prevented. Further, engine oil can be sealed in the oil storing chamber.

According to an embodiment of the present invention, the closing means includes the piston member for closing the communication hole to which the oil supply port and the oil return port open, the seal member for sealing the outer circumference of the piston member, and the spring member for biasing the piston member to the closed position of the communication hole. When the piston member is pushed against the biasing force of the spring member, the communication hole is opened. Accordingly, the oil storing device is enclosed before the oil storing device is mounted to the engine, so that the entry of dust into the oil storing chamber can be prevented. Further, by forming the connecting portion of the engine into a projecting shape fitted to the engaging portion, the oil storing device can be mounted to the engine by a simple operation. Further, engine oil can be preliminarily sealed in the oil storing chamber.

According to an embodiment of the present invention, engine oil is preliminarily sealed in the oil storing chamber. Accordingly, an oil change can be made by simply replacing the oil storing device by a new one.

According to an embodiment of the present invention, the piston member is provided with the grip for use in pulling the piston member out of the engaging portion. Accordingly, the piston member can be easily removed in the case of recycling the oil storing device, so that the spent engine oil can be easily discarded.

According to an embodiment of the present invention, the oil passage connected to the oil supply port and the oil return port is formed with the opening portion adapted to communicate with the outside of the oil storing chamber. Accordingly, in the case of recycling the oil storing device, the spent engine oil can be easily discarded and the inside of the oil storing device can be easily cleaned.

According to an embodiment of the present invention, the oil filter is mounted to the opening portion so as to communicate with the oil passage connected to the oil supply port and the oil return port. Accordingly, the oil filter can be replaced at the time of replacement of the oil storing device.

According to an embodiment of the present invention, the cap is mounted to the opening portion so as to communicate with the oil storing chamber. Accordingly, in the case of recycling the oil storing device, the cap may be removed, so that the spent engine oil can be easily discarded and the inside of the oil storing device can be easily cleaned.

According to an embodiment of the present invention, the cooling fin is formed on the outer surface of the body portion. Accordingly, the cooling performance for the engine oil can be improved.

According to an embodiment of the present invention, the body portion is provided with the inspection window for visual inspection of an oil level of the oil storing chamber in the body portion. Accordingly, in demounting the oil storing device from the engine, the level of the engine oil stored in the oil storing chamber can be checked at a glance, and the timing of removal of the oil storing device can be determined. More specifically, the oil level checked through the inspection window may be compared with the predetermined oil level. Accordingly, even when the oil storing device is demounted from the engine, spilling of the oil from the engine can be avoided to thereby ensure a clean operation.

According to an embodiment of the present invention, the fastening member for maintaining the engaged condition of the connecting portion of the crankcase and the engaging portion is provided at one end of the body portion. Accordingly, the oil storing device can be mounted to the engine easily and tightly without the need for any special tool.

According to an embodiment of the present invention, the engine has the oil storing device.

According to an embodiment of the present invention, the connecting portion is provided at a lower portion of the crankcase, and the inlet port connected to the oil supply port and the outlet port are formed integrally with each other in the connecting portion. Accordingly, an oil inlet structure and an oil outlet structure can be formed collectively at one position, so that the oil storing device can be mounted and demounted at one position. As a result, the number of parts such as screws in the engine can be reduced.

According to an embodiment of the present invention, the connecting portion projects downward from a lowermost portion of the crankcase, and the oil storing device is mounted on the crankcase so that the oil storing chamber is located below the crankcase. Accordingly, the oil storing chamber as an oil reservoir is located below the lowermost portion of the engine, so that an oil reservoir capable of maintaining engine performance can be formed and the engine oil can be reliably drained from the engine.

According to an embodiment of the present invention, when the engaging portion of the oil storing device is engaged with the connecting portion of the engine, the piston member is pushed by the connecting portion against the biasing force of the spring member, so that the oil supply port is connected to the inlet port of the crankcase and the oil return port is connected to the outlet port of the crankcase. Accordingly, the oil storing device can be easily mounted to the engine by a very simple push operation. In the case wherein the engine oil is preliminarily sealed in the oil storing chamber, the oil change can also be completed by this simple operation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A mode for carrying out the present invention will now be described.

A first preferred embodiment of the present invention will now be described in detail with reference toFIGS. 1 to 7.

In this preferred embodiment, the present invention is applied to a motorcycle such as a saddle seat type vehicle.

The general configuration of the motorcycle to which the present invention is applied will now be described in brief. Referring toFIG. 1, there is shown a motorcycle1in side elevation. The motorcycle1has a body frame F. The body frame F includes a head pipe26for steerably supporting a front fork25for supporting a front wheel WF, a pair of right and left main frames27extending rearwardly from the head pipe26so as to be inclined downwardly, and a pair of right and left pivot plates28extending downwardly from the rear portions of the right and left main frames27. A swing arm29is pivotably supported at its front end to the pivot plates28, and a rear wheel WR is supported to the rear portion of the swing arm29. A link30is provided between the lower portions of the pivot plates28and the front portion of the swing arm29. A shock absorber31is provided between the upper portions of the pivot plates28and the link30.

A power unit P is mounted to the main frames27and the pivot plates28. A rotating power output from the power unit P is transmitted through a drive shaft32extending in the longitudinal direction of the vehicle to the rear wheel WR.

The power unit P includes an engine E (seeFIG. 2). A side stand34is mounted to an engine body of the engine E or to the body frame F. In this preferred embodiment, the side stand34is mounted to the lower portion of the left pivot plate28of the body frame F. Accordingly, when the side stand34is operated to park the motorcycle1, the motorcycle1is inclined to the left side. InFIG. 1, symbols Fr, Rr, U, and D denote the front, rear, upper, and lower sides of the vehicle, respectively.

Referring toFIG. 2, there is shown an engine E in a side elevation. The engine E is a V-type water-cooled engine with an engine body having a front bank BF located on the front side in a condition wherein the engine E is mounted on the motorcycle1and a rear bank BR located on the rear side of the front bank BF. The engine body of the engine E has a crankcase35commonly provided for the front and rear banks BF and BR. A crankshaft36is rotatably supported to the crankcase35so as to extend in the lateral direction of the motorcycle1.

The crankcase35is composed of an upper case half35aand a lower case half35bjoined together. The upper case half35ais integrally formed with a front cylinder block38F and a rear cylinder block38R, these cylinder blocks38F and38R forming a V shape as viewed in side elevation. The axis of the crankshaft36lies on a joined surface37between the upper case half35aand the lower case half35b.

The front bank BF is generally composed of the front cylinder block38F mentioned above, a front cylinder head39F joined to the front cylinder block38F, and a front head cover40F joined to the front cylinder head39F. Similarly, the rear bank BR is generally composed of the rear cylinder block38R mentioned above, a rear cylinder head39R joined to the rear cylinder block38R, and a rear head cover40R joined to the rear cylinder head39R. An oil storing device41is connected to the lower portion of the crankcase35.

As mentioned above, the lower portion of the crankcase35of the engine E is provided with the oil storing device41. The structure of the oil storing device41and the structure of a mounting portion of the engine E for mounting the oil storing device41will now be described.

As shown inFIGS. 1,2, and7, the oil storing device41has a flattened cylindrical shape such that a mounted portion of the oil storing device41to be mounted to the engine E (a portion to be fixed by a fastening member58) is formed at one end of the oil storing device41. As shown inFIGS. 3 and 4, the vertical sectional shape of the oil storing device41is a substantially L-shape. Thus, the oil storing device41has a flattened structure extending rearwardly along the lower surface of the engine E in such a manner that the amount of projection of the oil storing device41under the vehicle can be reduced and a necessary oil storage capacity can be ensured in the oil storing device41. The oil storing device41has a substantially L-shaped body portion42. The body portion42has an engaging portion42aat one end adapted to be detachably connected to a connecting portion33of the crankcase35(the lower case half35b). The engaging portion42ais suitably fixed to the connecting portion33by using the fastening member58to be hereinafter described.

The internal structure of the oil storing device41is such that an oil supply port47afor supplying engine oil to the engine E and an oil return port47bfor introducing the engine oil circulated in the engine E and returned to the oil storing device41are provided in opposed relation to each other so as to open into a communication hole47eformed inside the engaging portion42a. The oil supply port47ais connected to a lower oil storing chamber44, and the oil return port47bis connected to an upper oil storing chamber43. The upper oil storing chamber43and the lower oil storing chamber44are separated from each other by a separation wall46. However, the upper and lower oil storing chambers43and44are connected to each other at the other end of the body portion42. In the mounted condition where the oil storing device41is mounted on the engine E, the upper and lower oil storing chambers43and44cooperate with each other to store a proper amount of engine oil.

The body portion42of the oil storing device41is formed at its other end (right end as viewed inFIG. 3) with a pair of upper and lower opening portions42bfor respectively making the upper and lower oil storing chambers43and44open to the outside of the oil storing device41. The upper opening portion42bcorresponding to the upper oil storing chamber43is formed with an externally threaded portion42dfor mounting an oil filter49. Accordingly, the upper and lower oil storing chambers43and44are connected through the oil filter49.

More specifically, the oil filter49is formed with an internally threaded portion49cfor engaging the externally threaded portion42dof the upper opening portion42bof the body portion42. An O ring49ais provided on one end of the outer cylindrical portion of the oil filter49, so as to tightly seal the mount surface between the body portion42and the oil filter49.

The engaging portion42aof the oil storing device41is provided with closing means50for closing the oil supply port47aand the oil return port47b. A circular cylindrical wall portion47is formed so as to extend downwardly from the engaging portion42a, thereby forming the communication hole47eto which the oil supply port47aand the oil return port47bopen. The closing means50includes a piston member53for closing the communication hole47eformed in the circular cylindrical wall portion47, a seal member52such as an O ring for sealing the outer circumference of the piston member53, and a spring member55such as a coil spring for biasing the piston member53to a closed position of the communication hole47e.

Accordingly, the oil storing chambers43and44can be tightly closed by the closing means50to thereby prevent entry of dust into the oil storing chambers43and44. Further, engine oil can be preliminarily sealed in the oil storing chambers43and44.

As described later, the piston member53is adapted to be pushed against the biasing force of the spring member55, thereby opening the communication hole47e.

As shown inFIG. 5, the piston member53is provided with a grip53cfor use in pulling the piston member53from the engaging portion42a. The grip53chas a bridge structure such that it spans the opposite inner circumferential portions of a recess53bformed on an upper end surface53eof the piston member53. Accordingly, the piston member53can be easily removed from the engaging portion42aby pinching the grip53cwith the operator's fingers or any suitable tool and then pulling the piston member53.

The seal member52is mounted on an outer circumferential surface53gof the piston member53. As shown inFIG. 6, the outer circumferential surface53gof the piston member53is formed with an outer circumferential groove50ahaving a semicircular cross section, and the inner half portion of the seal member52is fitted in the outer circumferential groove50aof the piston member53. On the other hand, the engaging portion42ahas an upper end portion48having an inner circumferential surface48bconstituting the communication hole47e. The inner circumferential surface48bof the upper end portion48of the engaging portion42ais formed with an inner circumferential groove48ahaving a semicircular cross section.

Thus, the seal member52is fitted in the inner circumferential groove48aof the engaging portion42a, thereby tightly closing the communication hole47e.

In the case of recycling the oil storing device41, the piston member53can be easily removed from the engaging portion42a, so that the engine oil (waste oil) stored in the body portion42can be easily discarded.

The outer surface of the body portion42is formed with a plurality of cooling fins42fextending horizontally on the front side of the body portion42and on the right and left sides of the body portion42. More specifically, the cooling fins42fhorizontally extend in the lateral direction on the front side of the body portion42and horizontally extend in the longitudinal direction on the right and left sides of the body portion42. Owing to the cooling fins42f, heat radiation from the body portion42can be effectively performed to thereby cool the engine oil.

The body portion42is provided with an inspection window42dformed of glass or the like at a position near the engaging portion42afor the purpose of visual inspection of the inside of the body portion42from the front side of the vehicle. The inspection window42dallows the operator to visually inspect the amount of oil stored in the oil storing chambers43and44. More specifically, in the case of draining the engine oil from the engine E, the operator can determine at a glance whether or not the engine oil in the engine E has entirely fallen into the oil storing chamber43and44, so that the operator can determine the timing of removal of the oil storing device41from the engine E.

An annular fastening member58is provided at one end of the body portion42so as to surround the engaging portion42a. The inner circumferential surface of the upper end portion of the fastening member58is formed with an internally threaded portion58b. The lower end portion of the fastening member58is formed as a jaw portion58areduced in inner diameter. Accordingly, the internally threaded portion58bof the fastening member58is adapted to engage with the externally threaded portion33dof the connecting portion33of the crankcase35, and the jaw portion58aof the fastening member58is adapted to abut against the flange48aof the upper end portion48. The fastening member58has a knurled outer circumferential surface58s.

The connecting portion33of the crankcase35is formed at the lower portion of the crankcase35. More specifically, as shown inFIG. 3, the connecting portion33is formed at the lowermost portion of the crankcase35so as to project downward therefrom. The connecting portion33has a two-step projection structure such that a large-diameter portion is formed at the base portion of the connecting portion33as the externally threaded portion33dand a small-diameter portion33aprojecting from the lower end of the large-diameter portion33dwith a shoulder portion33gis formed between the large-diameter portion33dand the small-diameter portion33a. The small-diameter portion33ais formed with an inlet port33band an outlet port33c. The inlet port33bis connected to a pipe33fconnected to an oil pump, and the outlet port33cis connected to a bottom surface35gof the crankcase35. Further, a seal member33esuch as an O ring is provided on the outer circumference of the base portion of the small-diameter portion33a.

The mounting and demounting operation for the oil storing device41will now be described.

In mounting the oil storing device41, the engaging portion42aof the oil storing device41is set under the connecting portion33of the crankcase35so as to be aligned to each other as shown inFIG. 3. Thereafter, the engaging portion42ais moved upwardly as shown by an arrow A inFIG. 3until abutting against the small-diameter portion33a. When the engaging portion42ais further moved upwardly, the piston member53is pushed by the small-diameter portion33aagainst the biasing force of the spring member55, so that the small-diameter portion33ais engaged into the engaging portion42aas shown inFIG. 4. More specifically, the piston member53is replaced by the small-diameter portion33ain the communication hole47e. In the fully engaged condition of the small-diameter portion33a, the seal member33emounted on the small-diameter portion33acomes into fit with the inner circumferential groove48aof the engaging portion42a. Finally, the fastening member58is turned, thereby fixing the oil storing device41to the engine E as shown inFIG. 4.

In this mounted condition, the oil supply port47aof the oil storing device41communicates with the inlet port33bof the engine E, and the oil return port47bof the oil storing device41communicates with the outlet port33cof the engine E. Further, the seal member33eof the connecting portion33of the engine E is fitted in the inner circumferential groove48aof the engaging portion42aof the oil storing device41, thereby ensuring a sealed condition. In this manner, the oil storing device41can be mounted to the engine E by a simple operation. In this preferred embodiment, the oil filter49can also be changed at the same time.

In the case wherein engine oil is preliminarily sealed in the oil storing device41, the oil change can also be completed by mounting this oil storing device41. In this manner, when the oil storing device41is replaced by a new one, the oil change can be completed at the same time. Accordingly, no oil filler port is needed, so that the structure of the engine E can be simplified.

The operation of a lubricating oil supply mechanism using the oil storing device41mounted on the engine E will now be described.

When the engine E having the oil storing device41is driven, the engine oil stored in the oil storing device41is sucked through the oil supply port47aand the inlet port33binto the engine E. Thereafter, the engine oil is supplied through an oil passage to a transmission (e.g., main shaft, counter shaft, clutch mechanism, etc.) and also through a main gallery branched from an oil passage to the crankshaft, pistons, camshafts, etc. of the engine E.

After performing the lubricating operation, the engine oil is returned to the bottom surface35gof the crankcase35and further returned through the outlet port33cand the oil return port47binto the upper oil storing chamber43of the oil storing device41. Thereafter, any impurities contained in the returned engine oil are removed by a filter element49bin the oil filter49, and the engine oil is next sent to the lower oil storing chamber44. Thereafter, the engine oil is supplied again from the oil storing device41to the engine E in a similar manner.

In the case of an oil change, the engine oil can be easily drained from the engine E because the oil storing chambers43and44as an oil reservoir are located at the lowermost position on the engine E. In demounting the oil storing device41for the purpose of oil change, the operator can determine whether or not the engine oil has entirely fallen into the oil storing device41by observing the inside of the oil storing device41through the inspection window42dafter the engine E is stopped and a given time has elapsed. After the engine oil has entirely fallen into the oil storing device41, the fastening member58is loosened by the operator's fingers or the like and the engaging portion42ais disengaged from the connecting portion33. At the same time, the piston member53is pushed back by the biasing force of the spring member55to close the communication hole47e. Accordingly, oil soiling such as oil spilling can be avoided in draining the oil, so that a clean oil draining operation can be performed. Thereafter, a new oil storing device41is mounted to the engine E as described above. In this manner, oil change can be made by simply replacing the oil storing device41by a new one.

Further, the oil storing device41can be recycled. More specifically, the piston member53can be removed and the oil filter49can also be removed. Accordingly, by removing the piston member53and the oil filter49, the spent engine oil stored in the body portion42can be easily discarded and the oil storing device41can be reused.

A second preferred embodiment of the present invention will now be described with reference toFIG. 8.

As shown inFIG. 8, a cap60is provided in place of the oil filter49shown inFIG. 4and the other structure is the same as that of the first preferred embodiment. Accordingly, the same parts are denoted by the same reference symbols and the description thereof will be omitted herein.

In the second preferred embodiment, the cap60is mounted on the opening portions42bof the body portion42. More specifically, the cap60engages with the externally threaded portion42dformed on the outer circumference of the upper opening portion42bcorresponding to the upper oil storing chamber43communicating with the oil return port47b. Further, the cap60has an opening60ccommunicating with the lower opening portion42bcorresponding to the lower oil storing chamber44. Accordingly, the cap60functions to connect the upper and lower oil storing chambers43and44, and the inside space60aof the cap60functions as an oil storing chamber.

According to the oil storing device41shown inFIG. 8, the cap60can be replaced by the oil filter49used in the first preferred embodiment. Accordingly, the body portion42has a compatible structure for both the cap60and the oil filter49.

The cap60is detachably connected to the body portion42. This structure is convenient in recycling the oil storing device41after it is demounted from the engine E. More specifically, after demounting the oil storing device41from the engine E, the cap60can be removed and the piston member53can also be removed. Accordingly, the spent engine oil stored in the oil storing chambers43and44can be easily discarded, and the inside of the body portion42can be easily cleaned.

A third preferred embodiment of the present invention will now be described with reference toFIGS. 9 and 10.

As shown inFIGS. 9 and 10, the third preferred embodiment is different from the first and second preferred embodiments in the structure of a body portion42B and the structure of a piston member53B. The other configuration is the same as that of the first and second preferred embodiments, so the same parts are denoted by the same reference symbols and the description thereof will be omitted herein.

In the oil storing device41according to the third preferred embodiment, the body portion42B is not formed with the opening portions42bshown inFIGS. 4 and 8, but the other end (right end as viewed inFIG. 9) of the body portion42B is closed. The body portion42B is provided with a separation wall47c. These upper and lower oil storing chambers43B and44B communicate with each other through a communication passage42gformed through the separation wall47c. Accordingly, the engine oil returned from the engine E to the oil storing device41flows from the oil return port47bthrough the upper oil storing chamber43B, the communication passage42g, and the lower oil storing chamber44B to the oil supply port47a.

As shown inFIG. 10which is an enlarged sectional view of an essential part of the piston member53B, a structure for retaining the seal member52is different from that of the first and second preferred embodiments. The seal member52is retained along the outer circumferential surface53gof the piston member53B. The piston member53B is composed of an upper small-diameter portion having a diameter D1and a lower large-diameter portion having a diameter D2larger than the diameter D1. The outer circumferential groove50ais formed between the upper small-diameter portion and the lower large-diameter portion. On the other hand, the inner circumferential surface48bof the mounted portion48B of the body portion42B is formed with an inner circumferential groove48dfacing the seal member52. The mounted portion48B has an upper portion having an inner diameter d4and a lower portion having an inner diameter d3larger than the inner diameter d4. The inner circumferential groove48dis formed between the upper portion and the lower portion. Accordingly, the seal member52retained in the outer circumferential groove50aand the inner circumferential groove48dis compressed in the vertical direction by the biasing force of the spring member55, so that the sealing performance for the piston member53B can be more ensured.

In mounting the oil storing device41according to the third preferred embodiment to the engine E, the piston member53B is pushed by the connecting portion33of the engine E. At this time, the seal member52retained in the outer circumferential groove50acan be smoothly disengaged from the inner circumferential groove48d, so that the piston member53B can be easily moved inward of the body portion42B. Accordingly, the oil storing device41can be easily mounted to the engine E. Further, in the mounted condition of the oil storing device41to the engine E, the seal member33emounted on the connecting portion33of the engine E is fitted in another inner circumferential groove48cof the upper portion of the mounted portion48B.

Having thus described the first, second, and third preferred embodiments of the present invention, the present invention is not limited to these preferred embodiments, but various modifications may be made. For example, the shape of the body portion, the engaging structure of the engaging portion, and the sealing structure are not especially limited, but may be modified as required.