JP6120441B2 - Oil drain plug - Google Patents

Description

  The present invention relates to an oil drain plug in which a magnet having an iron powder adsorption surface for adsorbing iron powder in oil is provided at the tip of a plug body disposed in a flow path through which oil for lubricating an iron member circulates.

  If the oil stored in the oil pan of an automobile transmission contains iron powder generated by the wear of iron members, it may cause malfunction of the hydraulic control valve and wear of the sliding part of the power transmission path. Therefore, it is necessary to attract and capture iron powder with a magnet arranged inside the oil pan.

  Therefore, a cylinder-shaped magnet that comes into contact with the oil is provided at the tip of an oil drain plug that is detachably provided on the bottom wall of the oil pan, and this magnet adsorbs and captures iron powder in the oil. 1 is known.

Japanese Utility Model Publication No. 6-1711

  By the way, it is effective to increase the size of the magnet in order to increase the amount of iron powder adsorbed. However, since other members such as a valve body are arranged inside the oil pan, it is possible to increase the size of the magnet. There is a problem of interference with the member.

  Moreover, in the above conventional one, the iron powder adsorption surface of the columnar magnet is composed of a cylindrical surface that is a two-dimensional convex curved surface and a circular flat surface at the tip thereof, so that only the end of the flat surface at the tip of the magnet is localized. Since the magnetic flux density is higher and the magnetic flux density is lower at the center of the flat surface, the iron powder is adsorbed only at the end of the flat surface and the iron powder is less likely to be adsorbed at the center of the flat surface. There is a problem that the amount of adsorbed powder becomes small.

  The present invention has been made in view of the above-described circumstances, and effectively adsorbs iron powder contained in oil with a magnet while avoiding interference of a magnet raised at the tip of an oil drain plug with other members. To capture.

To achieve the above object, according to the first aspect of the present invention, the iron that adsorbs the iron powder in the oil to the tip of the plug body disposed in the flow path through which the oil that lubricates the iron member circulates. An oil drain plug provided with a magnet having a powder adsorbing surface, wherein the iron powder adsorbing surface includes a first part and a second part from a distal end side toward a proximal end side, and a bus bar of the first part is the magnet And the second portion of the generatrix is composed of an arc centered at a point a predetermined distance away from the axis, and the radius relative to the radius of the generatrix of the first portion is the radius of the generatrix of the second portion is minor, and the second part is an oil drain plug, characterized in that is exposed from the distal end of the plug body is proposed.

According to the configuration of claim 1, the oil drain plug is a magnet having an iron powder adsorption surface that adsorbs iron powder in oil at the tip of the plug body disposed in a flow path through which oil for lubricating the iron member circulates. Therefore, iron powder in oil can be adsorbed and captured on the iron powder adsorption surface of the magnet. The iron powder adsorption surface includes a first portion and a second portion from the distal end side toward the proximal end side, the bus bar of the first portion is configured by an arc having a center on the axis of the magnet, and the bus bar of the second portion is is composed of a circular arc centered on the point from the axis a predetermined distance, the radius of the generatrix of the second portion relative to the radius of the generatrix of the first portion is minor, and the second part exposed from the distal end of the plug body since it is, and to prevent the corner portion pointed iron powder suction surface is formed by hard to interfere with another member, can be as much as possible size of the magnet to increase the adsorption amount of iron powder become.

  In addition, the iron powder adsorption surface of a conventional cylindrical magnet is composed of a cylindrical surface that is a two-dimensional convex curved surface and a circular flat surface at the tip of the cylindrical surface, so from the corner of the outer periphery of the flat surface with high magnetic flux density to the plug body However, according to the structure of claim 1, at least the tip of the iron powder adsorption surface is a spherical surface. Because it is configured, the magnetic flux density at the center of the tip of the iron powder adsorption surface is the highest, and it is possible not only to adsorb iron powder on the entire iron powder adsorption surface and increase the amount of iron powder adsorption Since the distance from the portion having the highest magnetic flux density to the plug main body is larger than that of the conventional one, the magnetic flux leakage to the plug main body is reduced and the iron powder adsorption efficiency is improved.

The longitudinal cross-sectional view of the lower part of a transmission. FIG. 2 is an enlarged sectional view taken along line 2-2 in FIG. 1. The longitudinal cross-sectional view of a magnet.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, a dish-shaped oil pan 12 is superimposed on the lower part of a transmission case 11 of an automobile transmission, and penetrates through bolt holes 12 b formed in a side wall 12 a of the oil pan 12 from below to above. The oil pan 12 is fastened to the mission case 11 by screwing a plurality of bolts 13 into screw holes 11 a formed on the periphery of the mission case 11.

  A valve body 14 and an oil strainer 15 are disposed under the mission case 11 so as to straddle the inside of the oil pan 12. The valve body 14 includes a first block 17, a second block 18, and a third block 19 that are laminated in three layers in the vertical direction and are integrally connected by a plurality of bolts 16... A plurality of hydraulic control valves and the like connected to each other by an oil passage are accommodated. Oil pumped by an oil pump (not shown) from the bottom of the oil pan 12 through the oil strainer 15 is adjusted to a predetermined hydraulic pressure by a hydraulic control valve or the like in the valve body 14 and is provided with a hydraulic clutch and pulley provided in the transmission. After being supplied to a lubricated part such as a piston, a torque converter or other hydraulic equipment or a bearing, it is returned to the oil pan 12 again.

  An oil drain plug 20 that is detachably attached to the side wall 12a of the oil pan 12 includes a head 21a having a circular cross section, a disc-shaped flange 21b continuous to the head 21a, and an outer periphery continuous to the flange 21b. The plug body 21 includes a shaft portion 21c having a male screw formed thereon, a cylindrical magnet support portion 21d continuous with the shaft portion 21c, and a magnet 22 supported by the magnet support portion 21d of the plug body 21. The plug body 21 is operated by a wrench inserted into a wrench hole 21e formed in the head portion 21a, and the shaft portion 21c is screwed into a drain hole 12c formed of a screw hole formed in the side wall 12a of the oil pan 12. The drain hole 12c is closed with the gasket 23 sandwiched between the flange 21b and the outer surface of the side wall 12a.

  A magnet 22 that is a rotating body obtained by rotating a predetermined shape of a bus bar around an axis L is integrally provided with an iron powder adsorption portion 22a and an attachment portion 22b, and the cylindrical attachment portion 22b is a cylindrical shape of the plug body 21. In a state where the magnet support portion 21d is fitted, the magnet support portion 21d is caulked inward to be integrally fixed to the plug body 21. In this state, the iron powder adsorption portion 22a of the magnet 22 protrudes from the plug body 21, and the iron powder adsorption surface 22c, which is the surface of the iron powder adsorption portion 22a, contacts the oil stored in the oil pan 12.

  As shown in FIG. 3, the iron powder adsorption surface 22c has a first portion a, a second portion b, and a first portion a, a second portion b, A third portion c is provided. The generatrix of the first portion a located on the most distal end side is formed by an arc having a center O1 on the axis L. The bus line of the second part b that continues smoothly on the base end side of the first part a is composed of an arc having a center O2 at a point separated from the axis L by a predetermined distance, and the bus bar of the first part a from the center O1. The radius R2 from the center O2 to the generatrix of the second part b is smaller than the radius R1 up to. The generatrix of the third portion c that continues smoothly on the base end side of the second portion b is a straight line parallel to the axis L. Therefore, the first part a which is a spherical surface and the second part b which is an aspherical surface are three-dimensional convex curved surfaces, and the third part c which is a cylindrical surface is a two-dimensional convex curved surface.

  In a state where the oil drain plug 20 is mounted on the side wall 12a of the oil pan 12, the iron powder adsorption surface 22c of the magnet 22 of the oil drain plug 20 faces the side surface of the valve body 14 with a slight gap α (see FIG. 2). To do.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  A large number of iron members such as gears, shafts, and bearings are arranged inside the transmission case 11 and their sliding surfaces are lubricated with oil. It is unavoidable to be mixed in. The relatively large iron powder is filtered and removed by the oil strainer 15 provided inside the oil pan 12, but the relatively small iron powder that cannot be removed by the oil strainer 15 circulates inside the mission case 11 and is There is a possibility that the hydraulic control valve in the body 14 is clogged, resulting in malfunction and wear of the sliding portion of the transmission.

  However, according to the present embodiment, since the magnet 22 provided at the tip of the oil drain plug 20 is disposed in the oil at the bottom of the oil pan 12, the iron powder in the oil is removed from the iron powder adsorption surface of the magnet 22. By adsorbing and removing by 22c, it is possible to prevent malfunction of the hydraulic control valve and wear of the sliding portion. Moreover, when the oil drain plug 20 is removed from the oil pan 12 at the time of oil replacement, the iron powder adsorbed to the magnet 22 of the oil drain plug 20 can be easily cleaned, so that maintenance is very good. is there.

  By the way, the iron powder adsorption surface of the conventional cylindrical magnet 22 'shown by a chain line in FIG. 2 is composed of a flat circular tip surface 22d and an outer peripheral surface 22e which is a cylindrical two-dimensional convex curved surface. Therefore, the magnetic flux density of the front end surface 22d is significantly higher than the magnetic flux density of the outer peripheral surface 22e, and iron powder can be substantially adsorbed only on the front end surface 22d, increasing the amount of iron powder adsorbed. It was difficult. Further, with respect to the tip surface 22d, only the corner portion 22f of the tip surface 22d has a locally high magnetic flux density, and the central portion of the tip surface 22d has a low magnetic flux density, so that iron powder is easily adsorbed only to the corner portion 22f. As a result, the iron powder is difficult to be adsorbed to the center, and the amount of iron powder adsorbed as a whole decreases.

  If the size of the magnet 22 'is increased, it is possible to increase the amount of iron powder adsorbed, but the conventional cylindrical magnet 22' has a protruding corner at the boundary between the tip surface 22d and the outer peripheral surface 22e. For this reason, there is a limit to increasing the size of the magnet 22 'if the gap β having the same size as the gap α is to be secured between the valve body 14 facing the magnet 22'.

On the other hand, the iron powder adsorption surface 22c of the magnet 22 of the present embodiment is constituted by a three-dimensional convex curved surface in which the first portion a and the second portion b at the tip thereof are smoothly curved, and the corner portion does not protrude. Therefore, the size of the magnet 22 in the direction of the axis L can be maximized while avoiding interference with the valve body 14 and the amount of iron powder adsorbed can be increased.

  Further, the first portion a at the tip of the iron powder adsorption surface 22c is formed of a spherical surface, and the permeance coefficient at the center of the tip of the iron powder adsorption surface 22c is increased, so that the iron powder is adsorbed on the entire iron powder adsorption surface 22c. By doing so, the amount of adsorption can be further increased. The permeance coefficient is a parameter depending on the shape of the magnet, and indicates the ease of leakage of magnetic flux from the magnet to the space. The larger the permeance coefficient, the higher the magnetic flux density and the higher the iron powder adsorption force.

  As for the iron powder adsorption surface of the conventional cylindrical magnet 22 ', the tip surface 22d where the magnetic flux density increases extends to the corner 22f at the boundary with the outer peripheral surface 22e, and the distance between the corner 22f and the plug body 21 is increased. Since L1 becomes small, there is a problem that magnetic flux easily leaks to the plug body 21 side and the adsorption efficiency of iron powder is lowered. However, according to the present embodiment, since the first portion a which is the tip of the iron powder adsorption surface 22c is formed of a spherical surface, the magnetic flux density at the center of the tip of the iron powder adsorption surface 22c is the highest, and the magnetic flux density. Since the distance L2 from the center portion of the tip portion having the highest height to the plug body 21 is larger than that of the conventional one, the leakage of magnetic flux to the plug body 21 is reduced and the iron powder adsorption efficiency is improved.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the shape of the iron powder adsorption surface 22c of the magnet 22 is specified in order to avoid interference with the valve body 14, but the counterpart member is not limited to the valve body 14, and the transmission case 11 It may be any internal member or the mission case 11 itself.

  The magnet of the present invention may be a metal magnet or a plastic magnet.

  In the embodiment, the oil drain plug 20 is provided on the side wall 12 a of the oil pan 12, but it may be provided on the bottom wall of the oil pan 12.

21 Plug body 22 Magnet 22c Iron powder adsorption surface a First part b Second part L Magnet axis O1 Center O2 Center R1 Radius R2 Radius

Claims (1)

An oil drain provided with a magnet (22) having an iron powder adsorption surface (22c) for adsorbing iron powder in oil at the tip of a plug body (21) arranged in a flow path through which oil for lubricating an iron member circulates. A plug,
The iron powder adsorption surface (22c) includes a first portion (a) and a second portion (b) from the distal end side toward the proximal end side, and the bus bar of the first portion (a) is the magnet (22). It is composed of an arc having a center (O1) on the axis (L), and the bus of the second part (b) is composed of an arc having a center (O2) at a point a predetermined distance from the axis (L). cage, wherein the first portion generatrix of radius of the second portion relative to the radius (R1) of the generatrix of (a) (b) (R2) is minor, and the second portion (b) is the plug body ( 21) An oil drain plug exposed from the tip of 21) .

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