Patent Application
20060254860
This nonprovisional application claims priority under 35 U.S.C. ยง 119(a) on Patent Application No. 2005-142482, filed in Japan on May 16, 2005, the entirety of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a mounting structure of an oil pump. More particularly, the present invention relates to a mounting structure of an oil pump, which can make simple and reliable connection of an oil inlet and outlet (inlet port and outlet port) of the oil pump to connected objects.
2. Description of Background Art
Japanese Patent Laid-Open No. 2001-140614 discloses an oil pump for an internal combustion engine that includes a feed pump for supplying oil from an oil tank to various lubricated sections of the engine and a scavenging pump integrated with the feed pump for returning the oil staying at a bottom portion of the engine to the oil tank. The feed pump and the scavenging pump have rotors coaxially mounted on a common drive shaft.
In the background art mentioned above, the joint plug and the two sealing members must be separately prepared when mounting the oil pump to a housing of a lubricated section. Furthermore, it is necessary to prepare any positioning members such as dowel pins for relatively positioning the oil pump and the housing of the lubricated section. As a result, the number of parts and the number of mounting steps become large.
There is a need for the present invention to provide a mounting structure of an oil pump that can reduce the number of parts and the number of mounting steps required to mount the oil pump to the housing of the lubricated section.
In a mounting structure of an oil pump for sucking lubricating oil from an inlet port and feeding the lubricating oil under pressure from an outlet port, the present invention includes the following aspects.
(1). The mounting structure includes a joint plug for oil-tightly connecting at least one of the inlet port and the outlet port to a connected object. The joint plug has one end portion preliminarily press-fitted with at least one of the inlet port and the outlet port and another end portion adapted to be oil-tightly connected to the connected object by using a sealing member.
(2). The oil pump includes a feed pump and a scavenging pump integrated with each other. The joint plug includes a first joint plug press-fitted with an inlet port of the feed pump and a second joint plug press-fitted with an inlet port of the scavenging pump. The first and second joint plugs having seat surfaces at the same level.
(3). The joint plug has a cylindrical portion and a circular flange portion formed at an axially central position of the cylindrical portion so as to have an outer diameter. One end portion of the joint plug is press-fitted until the flange portion abuts against an opening end of at least one of the inlet port and the outlet port.
According to the present invention, the following effects can be exhibited.
(1). According to the first aspect of the present invention, the joint plug is preliminarily fixed by press-fitting to the inlet port or the outlet port of the oil pump to thereby achieve oil tightness without using any sealing members. Thus, unlike the background art that requires sealing members to mount the oil pump, no sealing members are required. Furthermore, the joint plug is accurately positioned to the inlet or outlet port of the oil pump with no play, thereby exhibiting a positioning function. Accordingly, it is unnecessary to use any positioning members such as dowel pins for accurately positioning the oil pump to the connected object.
(2). According to the second aspect of the present invention, the first and second joint plugs have seat surfaces at the same level. Accordingly, even when the oil pump and the connected object are connected at two positions, the connection therebetween can be easily performed.
(3) According to the third aspect of the present invention, the joint plug is press-fitted into the inlet port or the outlet port of the oil pump until the flange portion abuts against the opening end of the inlet or outlet port. Accordingly, the seat surface of the joint plug can be set at a constant level.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, wherein the same or similar elements will be identified with the same reference numerals.
The feed pump of the oil pump 10 includes a feed pump housing 3. The scavenging pump of the oil pump 10 includes a first scavenging pump housing 1 and a second scavenging pump housing 4. An intermediate housing 2 is interposed between the first scavenging pump housing 1 and the feed pump housing 3. The housings 1, 2, 3, and 4 are oil-tightly joined together by using a plurality of screws 11. The drive shaft 5 is rotatably supported to the housings 1, 2, 3, and 4 so as to vertically extend therethrough.
A first scavenging pump rotor 11 is supported to the drive shaft 5 in a pump chamber 11a of the first scavenging pump housing 1. A feed pump rotor 13 is supported to the drive shaft 5 in a pump chamber 13a of the feed pump housing 3. A second scavenging pump rotor 14 is supported to the drive shaft 5 in a pump chamber 14a of the second scavenging pump housing 4.
As shown in
As shown in
In contrast, a connecting port 43 that is in communication with the oil pan is connected through a joint plug 53 to the inlet port 23 of the oil pump 10. A connecting port 44 that is in communication with the oil tank is connected through a joint plug 54 to the inlet port 24 of the oil pump 10. The joint plug 53 has a thin-walled cylindrical portion and a circular flange portion 53a formed at an axially central position of the cylindrical portion so as to have an outer diameter larger than that of the cylindrical portion. Similarly, the joint plug 54 has a thin-walled cylindrical portion and a circular flange portion 54a formed at an axially central position of the cylindrical portion so as to have an outer diameter larger than that of the cylindrical portion.
The inlet port 23 is tapered in such a manner that the inner diameter of the inlet port 23 gradually increases toward an opening end of the inlet port 23. Similarly, the inlet port 24 is tapered in such a manner that the inner diameter of the inlet port 24 gradually increases toward an opening end of the inlet port 24. One end portion of the joint plug 53 is preliminarily press-fitted with the inlet port 23 until the flange portion 53a abuts against the opening end of the inlet port 23, thereby achieving oil tightness. Similarly, one end portion of the joint plug 54 is preliminarily press-fitted with the inlet port 24 until the flange portion 54a abuts against the opening end of the inlet port 24, thereby achieving oil tightness.
For the purpose of simple connection of the other end portions of the joint plugs 53 and 54 to the respective connecting ports 43 and 44, the seat surfaces of the joint plugs 53 and 54 have the same level, i.e., the upper surfaces of the flange portions 53a and 54a of the joint plugs 53 and 54 have the same level. An O-ring 63 is fitted with the other end portion of the joint plug 53 so as to abut against the flange portion 53a, so that the connecting port 43 is oil-tightly connected to the joint plug 53 by a sealing function achieved by the combination of the flange portion 53a and the O-ring 63. Similarly, an O-ring 64 is fitted with the other end portion of the joint plug 54 so as to abut against the flange portion 54a, so that the connecting port 44 is oil-tightly connected to the joint plug 54 by a sealing function achieved by the combination of the flange portion 54a and the O-ring 64.
In operation, engine power or motor power is transmitted to a sprocket 30 connected to one end of the drive shaft 5 to thereby rotate the drive shaft 5. As a result, the lubricating oil is sucked into the oil pump 10 from the inlet ports 23, 24, and 25 by the suction forces of the feed pump and the scavenging pump. The lubricating oil supplied into the oil pump 10 is pressurized in the oil pump 10, and then fed under pressure from the outlet ports 21 and 22 to the oil cooler and the lubricated section.
According to this preferred embodiment, the joint plugs 53 and 54 are preliminarily fixed by press fitting to the inlet ports 23 and 24, respectively, to thereby achieve oil tightness without using any sealing members. Thus, unlike the background art, no sealing members are required between the inlet ports 23 and 24 and the joint plugs 53 and 54. Furthermore, the joint plugs 53 and 54 are accurately positioned to the inlet ports 23 and 24 of the oil pump 10 with no play, thereby exhibiting a positioning function. Accordingly, it is unnecessary to use any positioning members such as dowel pins for accurately positioning the oil pump to the connected object.
While the joint plugs 53 and 54 characteristic in the present invention are press-fitted with only the inlet ports 23 and 24 of the oil pump 10 in this preferred embodiment, the present invention is not limited to this preferred embodiment, but the joint plugs according to the present invention may be press-fitted with only the outlet ports 21 and 22 or both the inlet ports 23 and 24 and the outlet ports 21 and 22.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-142482 | May 2005 | JP | national |
