KR20160149947A

KR20160149947A - Oil drain plug

Info

Publication number: KR20160149947A
Application number: KR1020150087863A
Authority: KR
Inventors: 이종천; 여태은; 이종식
Original assignee: 이종천; 여태은; 이종식
Priority date: 2015-06-19
Filing date: 2015-06-19
Publication date: 2016-12-28
Also published as: KR101696546B1

Abstract

The present invention relates to an oil drain plug. According to an embodiment of the present invention, proposed is an oil drain plug including: a guide bolt wherein a through-hole with a screw thread is formed on a lower inner circumference and of which an outer circumference is bolt-coupled to a discharge port of an oil storing unit; a drain bolt having an oil discharge hole penetrated while having a stepped portion on an inner circumference, bolt-coupled to a lower inner circumference of the through-hole in a lower outer circumference of an upper part of a bolt head, inserted inside the oil storing unit via the through-hole, and sliding in a vertical direction along the through-hole after being bolt-released from the through-hole; an opening and closing shaft inserted into the oil discharge hole, blocking the oil discharge hole when bolt-coupling the drain bolt with the stepped portion of the oil discharge hole, and opening the oil discharge hole when the drain bolt slides downward; and a shaft supporter of which one end is joined to an upper part of a guide bolt and the other end is joined to an upper part of the opening and closing shaft and supporting the opening and closing shaft.

Description

Oil drain plug {OIL DRAIN PLUG}

The present invention relates to an oil drain plug. More specifically, the present invention relates to an oil drain plug capable of discharging oil remaining in an oil pan without being separated from an oil pan or the like.

The oil drain plug is a plug that plugs in the under cover of the transmission, engine, compressor, etc., or the exhaust hole (drain hole) at the bottom of the oil pan. Disconnect the plug when oil is changed or repaired to drain the oil.

For example, the oil pan serves as a reservoir for storing the lubricant used in engines, compressors, etc., and the oil stored in such an oil pan has to be replaced periodically since its lifetime is not permanent. At this time, a general method of oil change is to remove the oil drain plug located at the lowermost part of the engine from the exhaust hole, to discharge all the existing oil, and then to inject new oil from the top.

That is, conventionally, the oil drain plug installed in the discharge hole on the bottom surface of the oil storage unit such as the oil pan is separated / removed and the oil is discharged from the discharge hole of the oil pan or the like to change the oil.

Korean Registered Patent No. 10-0783547 (2007. 12. 07. Announcement)

However, in the conventional case, since oil is poured and discharged from the oil drain plug at the moment of separating / removing the oil drain plug from the oil pan or the like, oil is added to the operator's hand.

An object of the present invention is to provide an oil drain plug capable of discharging oil remaining in an oil storage unit such as an oil pan without separating from an oil storage unit such as an oil pan.

In order to solve the above-mentioned problems, according to one aspect of the present invention, there is provided a guide bolt having a through hole having a thread formed in a lower inner circumferential surface thereof, the outer circumferential surface being bolted to an exhaust hole of the oil storage unit; And an oil discharge hole having an inner circumferential stepped portion penetrated therethrough. The oil discharge hole is bolted to the lower inner peripheral surface of the through hole at the lower side of the outer peripheral surface of the upper portion of the head of the bolt, is inserted into the oil storage unit through the through hole, A drain bolt slidably moved up and down along the through hole; An opening / closing shaft which is inserted into the oil discharge hole and opens the oil discharge hole when the drain bolt slides downward while blocking the oil discharge hole when the drain bolt is bolted according to the inner peripheral surface step of the oil discharge hole; And a shaft support which is engaged at one end with the upper side of the guide bolt and at the other end with the upper end of the opening and closing shaft and supports the opening and closing shaft.

In this case, in one example, the drain bolt may further include a stop member formed at the upper end of the outer circumferential surface and limiting the range of sliding downward movement.

The stop member is a snap ring inserted into the third ring groove formed around the upper end portion of the outer circumferential surface of the drain bolt. The snap ring is moved to the inner step by the step of the upper end or the inner circumferential surface of the through hole at the time of the maximum downward movement within the sliding downward movement. It takes.

Further, in one example, the drain bolt may further include a hose connector projecting downward from the head of the bolt.

In another example, the top height of the guide bolt is formed to coincide with the bottom surface of the oil storage unit when the maximum bolt is engaged with the fastening hole or is formed lower than the bottom surface, and the top height of the drain bolt, And is formed to coincide with or be lower than the top height.

At this time, in one example, the shaft support includes a cylindrical ring-shaped coupling portion that is screwed with an upper inner circumferential surface of the through-hole of the guide bolt or an upper outer circumferential surface of the guide bolt, a fixing groove fitting portion that fits into a fixing groove formed around the upper end portion of the opening- And a plurality of connection supports connecting the cylindrical ring-shaped coupling portion and the fixing groove-fitted portion.

Further, in one example, a first ring groove is formed in the inner circumferential surface of the through hole, the outer circumferential surface of the drain bolt moving up and down along the through hole by the first O-ring sandwiched in the first ring groove is sealed between the inner circumferential surface of the through hole, And a second ring groove formed around a lower end portion of a diameter larger than the middle diameter of the through hole, wherein a second O-ring inserted in the second ring groove during vertical movement of the drain bolt in the bolt fastening section with the lower inner circumferential surface of the through hole, The lower end portion of the opening and closing shaft is brought into contact with the lower end portion of the opening / closing shaft by the large-diameter portion of the inner circumferential surface of the oil discharge hole due to the downward sliding movement of the drain bolt after the drain bolt is moved downward And the sealing by the second O-ring is released.

At this time, in another example, a first gasket is provided between the bolt head projected horizontally from the lower part of the outer circumference of the guide bolt and the periphery of the bottom fastening hole, and the upper surface of the bolt head of the drain bolt and the lower surface of the bolt head of the guide bolt A second gasket is provided.

According to one embodiment of the present invention, the oil remaining in the oil storage unit such as the oil pan can be discharged without separating from an oil storage unit such as an oil pan.

Thus, the oil drain plug is not entirely separated / detached during the oil draining operation, the drain bolt is released from the guide bolt by releasing the bolt from the guide bolt, and the drain bolt is pulled by sliding to discharge the oil through the oil drain hole. It is possible to prevent or reduce the oil from being put on the hand during discharge.

It is apparent that various effects not directly referred to in accordance with various embodiments of the present invention can be derived by those of ordinary skill in the art from the various configurations according to the embodiments of the present invention.

1 is a perspective view schematically showing an oil drain plug according to one embodiment of the present invention.
Fig. 2 is a view showing a state of separation of the oil drain plug shown in Fig. 1. Fig.
FIG. 3A is a cross-sectional view showing a state where the oil storage plug of the oil drain plug according to FIG.
3B is a cross-sectional view showing a state in which the drain bolt of the oil drain plug according to FIG. 1 is released from the bolt fastening with the guide bolt.
3C is a cross-sectional view illustrating a state in which the drain bolt of the oil drain plug according to FIG. 1 is slid downward to a maximum extent along the through hole of the guide bolt.
4 is a partially cutaway perspective view schematically showing an oil drain plug according to another embodiment of the present invention.
5 is a view showing a state of separation of the oil drain plug according to Fig.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing the configuration of a first embodiment of the present invention; Fig. In the description, the same reference numerals denote the same components, and a detailed description may be omitted for the sake of understanding of the present invention to those skilled in the art.

As used herein, unless an element is referred to as being 'direct' in connection, combination, or placement with other elements, it is to be understood that not only are there forms of being 'directly connected, They may also be present in the form of being connected, bonded or disposed. The same is true of terms that include the meaning of 'contact' such as 'on', 'above', 'below', or 'below'. Directional terms may be construed to encompass corresponding relative directional concepts as the reference element is inverted or its direction is changed.

It should be noted that, even though a singular expression is described in this specification, it can be used as a concept representing the entire constitution unless it is contrary to, or obviously different from, or inconsistent with the concept of the invention. It is to be understood that the phrases "including", "having", "having", "comprising", etc. in this specification are intended to be additionally or interchangeable with one or more other elements or combinations thereof.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which: FIG.

An oil drain plug according to an aspect of the present invention will be described in detail with reference to the drawings. Here, reference numerals not shown in the drawings to be referred to may be reference numerals in other drawings showing the same configuration.

FIG. 1 is a perspective view schematically showing an oil drain plug according to one embodiment of the present invention, FIG. 2 is a view showing a separated state of an oil drain plug according to FIG. 1, Fig. 3B is a cross-sectional view showing a state in which the drain bolt of the oil drain plug according to Fig. 1 is released from the bolt fastening with the guide bolt, Fig. 3C is a cross- FIG. 4 is a sectional view showing a state in which the drain bolt of the oil drain plug according to another embodiment of the present invention is slid down to the maximum extent along the through hole of the guide bolt. And FIG. 5 is a view showing a state of separation of the oil drain plug according to FIG.

Referring to Figs. 1 to 5, an oil drain plug according to one example includes a guide bolt 10, a drain bolt 30, an opening and closing shaft 50, and a shaft support 70. The oil drain plug is fastened to the discharge hole of the oil storage unit 1 such as an oil pan and becomes a passage for discharging oil from the oil storage unit 1 such as an oil pan. For example, the oil drain plug is used to discharge oil from the oil storage unit 1 in various product fields such as various transmissions, engines and compressors. In the present invention, the oil storage unit 1 refers to an oil pan of an engine, an oil pan of an automatic transmission, a transmission, and an oil storage portion such as a longitudinal reduction gear unit. The oil drain plug according to the embodiment of the present invention can discharge the oil in a state where it is not separated from the oil storage unit 1 such as an oil pan unlike the prior art. 2 and 5, the oil drain plug according to the embodiment of the present invention is formed such that the drain bolt 30 is bolted to the through hole 11 of the guide bolt 10 And the assembly of the shaft support 50 and the shaft support 70 is assembled / engaged so that the opening / closing shaft 50 is inserted into the oil discharge hole 31 of the drain bolt 30, so that the oil drain plug can be assembled . In describing the example of the present invention, although the oil drain plug is shown as being vertically fastened to the bottom surface of the oil storage unit 1 such as an oil pan, the present invention is not limited thereto, Or may be fastened in a horizontal direction to the bottom surface of the oil storage unit 1 or may be fastened in a horizontal direction to the bottom surface of the oil storage unit 1 such as an oil pan Be careful.

The respective constitutions of the oil drain plug according to the example of the present invention will be described in detail with reference to the drawings.

The guide bolt 10 will be described with reference to Figs. The guide bolt 10 is a portion directly coupled to the discharge hole of the oil storage unit 1 such as an oil pan. The outer surface of the guide bolt 10 is bolted to the discharge hole of the oil storage unit 1 such as an oil pan. That is, the outer circumferential surface thread 12 is formed on the outer circumferential surface of the guide bolt 10 and is bolted (screwed) to the discharge hole of the oil storage unit 1. [ At this time, even if the guide bolt 10 is not detached from the discharge hole of the oil storage unit 1 such as an oil pan, the drain bolt 30, which will be described below, Can be discharged.

The guide bolt (10) has a through hole (11). At this time, a thread 11c is formed on the lower inner circumferential surface of the through-hole 11. The lower outer circumferential surface thread 32 of the drain bolt 30 is bolted (screwed) to the lower inner circumferential surface thread 11c.

At this time, in one example, the height of the upper end of the guide bolt 10 coincides with the bottom surface of the oil storage unit 1 when the maximum bolt is engaged with the discharge hole of the oil storage unit 1 such as an oil pan, . Thus, the guide bolt 10 is not obstructed in discharging the oil remaining on the bottom of the oil storage unit 1 such as an oil pan.

In one example, the through hole 11 of the guide bolt 10 may be provided with an inner peripheral surface step 11b formed by a step between the upper inner circumferential surface and the lower inner circumferential surface. At this time, the inner peripheral surface step 11b of the through hole 11 can limit the maximum range of sliding downward movement of the drain bolt 30 inserted in the through hole 11. [ For example, when the drain bolt 30 is slid downward, the stop member of the drain bolt 30, for example, the snap ring 37 is caught by the inner peripheral surface step 11b of the through hole 11 and the maximum range of sliding downward movement is limited . The stop member of the drain bolt 30 such as the snap ring 37 is caught by the upper end of the through hole 11 and is slid downward The maximum range of movement may be limited.

For example, when the inner peripheral surface step 11b is formed in the through hole 11, a thread 11d is formed on the inner peripheral surface of the through hole 11 having a large diameter so that the shaft support 70 described below can be screwed. The diameter of the lower inner peripheral surface of the through hole 11 is smaller than the inner diameter of the shaft support 70 when the shaft support 70 is screwed (bolted) to the upper inner peripheral surface of the through hole 11. Although not shown, a screw thread (not shown) is formed on the outer peripheral surface of the upper portion of the guide bolt 10 instead of the upper inner circumferential surface thread 11d of the through hole 11 and the upper outer circumferential surface thread of the guide bolt 10 The inner side of the shaft support 70 can be screwed. When the shaft support 70 is screwed to the upper outer circumferential surface thread (not shown) of the guide bolt 10, the outer circumferential surface of the guide bolt 10 has a stepped portion and the outer diameter of the shaft support 70, And the outer circumferential surface of the lower portion of the outer circumferential surface. At this time, a thread (not shown) is formed on the outer circumferential surface of the shaft supporter 70 corresponding to the upper outer circumferential surface thread (not shown) of the guide bolt 10 so that the lower outer circumferential surface thread 12 of the guide bolt 10 (Screwed) to the discharge hole of the oil storage unit 1 such as an oil pan.

In one example, the first ring groove 11a is formed on the inner circumferential surface of the through hole 11 of the guide bolt 10. At this time, the outer circumferential surface of the drain bolt 30, which moves up and down along the through hole 11, can be sealed between the inner circumferential surface of the through hole 11 and the outer circumferential surface of the drain bolt 30 by the first O ring 21 fitted in the first ring groove 11a.

Subsequently, in one example, the guide bolt 10 has a bolt head 13 projecting horizontally at the bottom of the outer circumference. A first gasket 14 is installed between the upper surface of the protruding portion of the bolt head 13 of the guide bolt 10 and the lower surface of the circumference of the discharge hole of the oil storage unit 1, ) And the discharge hole of the oil storage unit (1).

Next, the drain bolt 30 will be described in detail with reference to FIGS. 1 to 5. FIG. The drain bolt (30) is inserted into the through hole (11) of the guide bolt (10). At this time, the drain bolt 30 is bolted to the lower inner peripheral surface of the through hole 11, passes through the through hole 11, and is inserted into the oil storage unit 1 such as an oil pan. At this time, the lower inner peripheral surface of the through hole 11 may be bolted to the lower outer peripheral surface of the drain bolt 30. For example, the lower outer circumferential surface of the drain bolt 30, which is the bolt engagement portion with the inner circumferential surface of the through hole 11, is located above the bolt head 35 of the drain bolt 30. Meanwhile, the drain bolt 30 can be slid up and down along the through hole 11 after the bolt is unfastened from the through hole 11. The outer circumferential surface of the drain bolt 30 can be slidably moved along the lower inner circumferential surface of the through hole 11 due to the inner circumferential surface step of the through hole 11 after the bolt fastening with the through hole 11 is released. At this time, the diameter of the bolt connecting portion between the lower outer circumferential surface of the drain bolt 30 and the lower inner circumferential surface of the through hole 11 is formed to be larger than the diameter of the sliding portion of the lower inner circumferential surface. That is, the sliding portion of the lower inner circumferential surface of the through hole 11 is formed on the upper side of the bolt connecting portion of the lower inner circumferential surface of the through hole 11, and the diameter thereof is small.

Referring again to the drain bolt 30, the drain bolt 30 is provided with an oil discharge hole 31. The oil discharge hole 31 has an inner circumferential surface stepped portion and is passed through the inside.

For example, in one example, the top height of the drain bolt 30 is formed to coincide with or be lower than the top height of the guide bolt 10 when the sliding bolt 30 moves downward along the through hole 11. Accordingly, the oil inside the oil storage unit 1 such as the oil pan can be discharged to the outside along the oil discharge hole 31 of the drain bolt 30. [ For example, when the inner circumferential surface step 11b is formed in the through hole 11, a groove (not shown) having a lower height than the circumference is formed around the upper end of the drain bolt 30, The height of the groove (not shown) around the upper end of the drain bolt 30 at the time of movement can be made lower than or at least equal to the height of the inner peripheral surface step 11b of the through hole 11. [ The oil flowing into the through hole 11 of the guide bolt 10 in the oil storage unit 1 such as an oil pan is lower than the inner circumferential surface step 11b or the oil flowing into the through hole 11 of the drain bolt 30 And can be discharged to the oil discharge hole 31 through a groove (not shown) around the upper end.

Further, in one example, the drain bolt 30 may further include a stop member. The stop member is formed at the upper end of the outer circumferential surface of the drain bolt (30), and limits the sliding downward movement range of the drain bolt (30). For example, in one example, the stop member may be a snap ring 37 that is fitted in the third ring groove 33a formed around the upper end of the outer circumferential surface of the drain bolt 30. At this time, the snap ring 37 is hooked on the inner step 11b by the step of the upper end or the inner circumferential surface of the through hole 11 when the downward movement of the sliding downward is the maximum downward movement. The stop member may be a protrusion horizontally protruding around the upper end of the outer circumferential surface of the drain bolt 30.

4 and 5, in one example, the drain bolt 30 may further include a hose connector 36 protruding downward from the bolt head 34. The hose connecting port 36 is formed by loosening the drain bolt 30 bolted to the through hole 11 of the guide bolt 10 so that the oil does not touch the operator's hand when the oil is drained from the oil pan, When the hose is connected to the drain hole 36 and the bolt head 34 of the drain bolt 30 is pulled down and pulled out, the oil discharge hole 31 is opened and the oil in the oil pan is discharged.

In another example, a second gasket 35 is provided between the upper peripheral surface of the bolt head 34 of the drain bolt 30 and the lower surface of the bolt head 13 of the guide bolt 10, The guide bolt 10 and the drain bolt 30 can be further sealed apart from the first O-ring 21 provided on the inner circumferential surface of the hole 11. [

Next, with reference to Figs. 1 to 5, the opening / closing shaft 50 will be specifically described. The opening and closing shaft 50 is inserted into the oil discharge hole 31 of the drain bolt 30. The opening and closing shaft 50 blocks the oil discharge hole 31 when the bolt is fastened to the through hole 11 of the drain bolt 30 according to the inner peripheral surface step of the oil discharge hole 31, The oil drain hole 31 is opened when the drain bolt 30 slides downward. That is, the oil discharge hole 31 of the drain bolt 30 is formed to be smaller than the diameter of the upper discharge hole 31b communicated with the diameter of the lower discharge hole 31a by the inner peripheral step difference, The lower discharge hole 31a is closed in the lower discharge hole 31a and the seal is released in the upper discharge hole 31b having a larger diameter so that oil in the oil storage unit 1 such as an oil pan is discharged along the oil discharge hole 31 .

For example, in one example, a sealing ring, that is, a second O-ring 23 is provided around the lower end portion 51 of the opening and closing shaft 50, so that the lower discharge hole 31a in the lower discharge hole 31a It can be sealed. At this time, the diameter of the intermediate portion of the opening and closing shaft 50 may be smaller than the diameter of the lower end portion. A second ring groove 51a formed around a lower end portion 51 of a diameter larger than the middle diameter of the opening and closing shaft 50 and having a second O-ring 23 fitted in the second ring groove 51a, The inner circumferential surface of the lower discharge hole 31a of the small diameter due to the inner peripheral surface step of the hole 31 and the lower end portion 51 of the opening and closing shaft 50 can be sealed. 3a and 3b, the sealing between the lower end portion 51 of the opening and closing shaft 50 and the lower inner circumferential surface of the small diameter due to the inner circumferential surface step difference of the oil discharge hole 31 causes the drain bolt 30 and the through- In the vertical moving section of the drain bolt 30 in the bolt fastening section with the lower inner circumferential surface of the bolt 30. For example, referring to FIG. 3C, when the drain bolt 30 is downwardly pulled after the drain bolt 30 is moved to the maximum downward position in the bolt fastening interval between the drain bolt 30 and the lower inner circumferential face of the through hole 11 The lower end portion 51 of the opening and closing shaft 50 is disposed in the upper section of the large diameter due to the inner peripheral surface step of the oil discharge hole 31 and the second O- The sealing by the sealing member is released.

Next, the shaft support 70 will be described in detail with reference to Figs. The shaft support 70 has one end engaged with the upper side of the guide bolt 10 and the other end engaged with the upper end of the opening and closing shaft 50 to support the opening and closing shaft 50. The shaft support 70 supports and fixes the opening and closing shaft 50 so that the lower end portion 51 of the opening and closing shaft 50 fixed when sliding down the through hole 11 of the drain bolt 30 is inserted into the oil discharge hole 31 from the lower discharge hole 31a.

For example, in one example, the shaft support 70 may include a cylindrical ring-shaped fastening portion 71, a fixing groove-fitting portion 75, and a plurality of connection supports 73. At this time, the cylindrical ring type fastening portion 71 is screwed to the upper inner circumferential surface of the through hole 11 of the guide bolt 10 or the upper outer circumferential surface of the guide bolt 10. For example, a thread 71a may be formed on the outer circumferential surface of the cylindrical ring-shaped fastening portion 71 and screwed to the upper inner circumferential surface thread 11d of the through hole 11 of the guide bolt 10. [ The fixing groove fitting portion 75 is fitted in the fixing groove 53a formed around the upper end portion of the opening and closing shaft 50. The plurality of connection supports 73 connect the cylindrical ring type fastening portion 71 and the fixing groove fitting portion 75. At this time, the oil in the oil storage unit 1 such as the oil pan can be discharged through the oil discharge hole 31 through the space between the plurality of connection supports 73.

The foregoing embodiments and accompanying drawings are not intended to limit the scope of the present invention but to illustrate the present invention in order to facilitate understanding of the present invention by those skilled in the art. Embodiments in accordance with various combinations of the above-described configurations can also be implemented by those skilled in the art from the foregoing detailed description. Accordingly, various embodiments of the present invention may be embodied in various forms without departing from the essential characteristics thereof, and the scope of the present invention should be construed in accordance with the invention as set forth in the appended claims. Alternatives, and equivalents by those skilled in the art.

1: Oil storage unit 10: Guide bolt
11: Through hole 11a, 33a, 51a: Ring groove
11b: inner peripheral surface step 11c: lower inner peripheral surface thread
11d: upper inner circumference thread 12: outer circumference thread
13, 34: bolt head 14, 35: gasket
21, 23: O-ring 30: drain bolt
31: Oil drain hole 32: Lower outer circumferential surface thread
36: Hose connector 37: Snap ring
50: opening and closing shaft 51:
53a: Fixing groove 70: Shaft support
71: cylindrical ring type fastening part 73: connection support
75: Fixing groove fitting portion

Claims

A guide bolt having a through hole having a thread formed in a lower inner circumferential surface thereof and having an outer circumferential surface bolted to an exhaust hole of the oil storage unit;
And an oil discharge hole having an inner circumferential stepped portion penetrated therethrough and being bolted to a lower inner circumferential surface of the through hole at a lower side of an outer circumferential surface of an upper portion of the bolt head and being inserted into the oil storage unit through the through hole, A drain bolt slidably moving up and down along the through hole after the bolt is unfastened;
An opening / closing shaft inserted into the oil discharge hole to block the oil discharge hole when the drain bolt is bolted to the oil discharge hole and to open the oil discharge hole when the drain bolt slides downward; And
And a shaft support member having one end engaged with the upper side of the guide bolt and the other end engaged with the upper end of the opening and closing shaft and supporting the opening and closing shaft.

In claim 1,
Wherein the drain bolt further comprises a stop member formed at the upper end of the outer circumferential surface and limiting a range of the sliding downward movement.

In claim 2,
Wherein the stop member is a snap ring that is fitted in a third ring groove formed around an upper end portion of an outer circumferential surface of the drain bolt,
Wherein the snap ring is caught by an inner edge of an upper end or an inner peripheral step of the through hole when moving downward in the range of the sliding downward movement.

In claim 1,
Wherein the drain bolt further comprises a hose connector protruding downward from the head of the bolt.

The method according to any one of claims 1 to 4,
Wherein an upper end of the guide bolt is formed to coincide with a bottom surface of the oil storage unit when the maximum bolt is engaged with the fastening hole,
Wherein an upper end of the drain bolt is formed to be coincident with or lower than a height of an upper end of the guide bolt when the sliding bolt moves downward along the through hole.

In claim 5,
Wherein the shaft support includes a cylindrical ring-shaped coupling part screwed with an upper inner circumferential surface of the through-hole of the guide bolt or an upper outer circumferential surface of the guide bolt, a fixing groove fitting part fitted into a fixing groove formed around the upper end of the opening- And a plurality of connection supports connecting the ring-shaped coupling portion and the fixing groove-fitted portion.

In claim 5,
A first ring groove is formed in the inner peripheral surface of the through hole,
The outer circumferential surface of the drain bolt moving upward and downward along the through-hole by the first O-ring inserted into the first ring groove is sealed between the inner circumferential surface of the through-hole,
Wherein the opening and closing shaft has a second ring groove formed around a lower end portion of a diameter larger than the intermediate diameter,
And a second O-ring inserted in the second ring groove during up-and-down movement of the drain bolt in a bolt fastening section with the lower inner circumferential surface of the through-hole, between the lower inner circumferential surface of the small diameter and the lower end portion of the opening- Is sealed,
A lower end of the opening / closing shaft is disposed in an upper section of a large diameter due to an inner circumferential surface step of the oil discharge hole as the drain bolt is slid downward after the drain bolt is moved downward in the bolt fastening section, Is released from the oil seal.

In claim 7,
A first gasket is installed between the bolt head projected horizontally from the lower portion of the outer circumference of the guide bolt and the periphery of the bottom fastening hole,
Wherein a second gasket is provided between a top surface of the bolt head of the drain bolt and a bottom surface of the bolt head of the guide bolt.