JP4882969B2 - Drain mechanism of fluid filter - Google Patents

Description

  The present invention relates to a fluid filter drain mechanism.

  2. Description of the Related Art Conventionally, as a fluid filter, for example, an element exchange type fluid filter that replaces a filter element when a filter medium is clogged due to use for a predetermined time and reaches the end of its life is generally known.

  As a drain mechanism of such an element exchange type fluid filter, a drain mechanism in which a metal drain bolt is screwed into a drain hole of a metal cap is known (see, for example, Patent Document 1). Accordingly, when the filter element is replaced, prior to separation of the case and the cap, the drain bolt can be loosened and removed from the drain hole to open the drain hole, and the residual oil inside the housing can be discharged.

In recent years, it has been proposed to change the drain bolt from a conventional metal to a synthetic resin for weight reduction or the like. In this case, in the conventional drain mechanism, since the drain bolt made of synthetic resin is coupled to the drain hole of the metal cap only by screwing, the drain bolt and the cap having different thermal expansion coefficients are thermally deformed. As a result, the tightening torque of the drain bolt is lowered, the drain bolt is easily loosened, and oil leakage may occur. Even when the entire cap together with the drain bolt is made of synthetic resin, there is a risk that the tightening torque will decrease and the drain bolt will loosen due to the vibration caused by the long-time operation of the device equipped with the fluid filter.
Further, when tightening the drain bolt made of synthetic resin, depending on the operator, the tightening torque becomes too high, and the drain bolt may be damaged.

  In addition, as conventional screw locking technology, (1) providing a biting projection that bites into the object to be tightened on the back surface of the washer, (2) providing a number of head projections on the back surface of the bolt head, It is known to provide a large number of washer protrusions that engage the head protrusions on the surface (see, for example, FIG. 5 and paragraph numbers [0025] and [0028] of Patent Document 2). However, even if these technologies are applied to the drain mechanism using the drain bolt made of the above-mentioned synthetic resin, the projection formed on the drain bolt is scraped or the projection on the other side is overcome when the drain bolt deteriorates. There is a risk of damage without being able to withstand the force.

JP-A-2005-103502 JP-A-9-170616

  The present invention has been made in view of the above situation, and provides a fluid filter drain mechanism having a simple structure that can prevent loosening and overtightening that tend to occur when a resin drain bolt is used. Objective.

The present invention is as follows.
1. In a drain mechanism of a fluid filter, comprising: a cap attached to a case and having a drain hole; and a drain bolt screwed with a predetermined tightening torque by relative rotation with the cap to close the drain hole.
The drain bolt is made of resin,
A first restricting portion provided on the cap; a second restricting portion provided on the drain bolt and contacting or engaging the first restricting portion by relative rotation of the cap and the drain bolt; and the drain bolt An elastic support portion provided and elastically supporting the second restricting portion ;
The fluid filter drain mechanism according to claim 1, wherein the elastic support portion includes a thin wall portion and / or a hole portion formed in a flange portion of the drain bolt .
2. The bottom of the cap is provided with a seal member to which the flange of the drain bolt is pressed, and the first restricting portion is provided on the outer peripheral side of the seal member at the bottom of the cap. 2. The restricting portion is provided on the outer peripheral side of a portion of the flange portion of the drain bolt that is in pressure contact with the seal member . A drain mechanism of the fluid filter described.
3. The bottom of the cap is provided with a seal member to which the flange of the drain bolt is pressed, and the first restricting portion is provided on the inner peripheral side of the seal member at the bottom of the cap, The second restricting portion is provided on the inner peripheral side of the portion of the collar portion of the drain bolt that is in pressure contact with the seal member . A drain mechanism of the fluid filter described.
4). Each of the first restricting portion and the second restricting portion is a protrusion . To 3. The drain mechanism of the fluid filter as described in any one of these .
5. One of the first restricting portion and the second restricting portion is a protrusion, and the other is a recess in which the protrusion is engaged . To 3. The drain mechanism of the fluid filter as described in any one of these.

According to the drain mechanism of the fluid filter of the present invention, when the drain bolt is rotated relative to the cap in the direction in which the drain bolt is tightened, the first restriction is applied when the drain bolt is screwed to the cap with a predetermined tightening torque. The second restricting portion abuts on the part and is positioned at a position where the second restricting portion abuts on or approaches the first restricting portion, or the second restricting portion engages with the first restricting portion. Therefore, even if the drain bolt tries to rotate in the loosening direction with respect to the cap from this state, the loosening around the drain bolt is restricted by the contact or engagement of the first restricting portion and the second restricting portion, and the occurrence of fluid leakage is prevented. Can be prevented. Further, the operator can confirm that the tightening torque of the drain bolt has become appropriate by the feeling that the second restricting part gets over the first restricting part and the feel of the engagement of the first restricting part and the second restricting part. . As a result, excessive tightening of the drain bolt can be prevented and breakage of the drain bolt can be prevented. In addition, since the first restricting portion is provided integrally with the cap and the second restricting portion and the elastic support portion are provided integrally with the resin drain bolt, the loosening restricting structure can be configured without increasing the number of parts. Further, since the second restricting portion is elastically supported by the elastic support portion, the pressure applied to the second restricting portion can be absorbed or dissipated by the elastic support portion to prevent damage to both restricting portions, and the drain bolt Can be tightened or loosened without difficulty.
Further, the elastic support portion, said since a thin portion formed at the flange portion of the drain bolt and / or holes, can be easily set easily elastic support portion bending on the surface side of the flange portion of the drain bolt.
The bottom of the cap is provided with a seal member that presses the flange of the drain bolt, and the first restricting portion is provided on the outer peripheral side of the seal member at the bottom of the cap, When the second restricting portion is provided on the outer peripheral side of the portion of the flange portion of the drain bolt that is in pressure contact with the seal member, the seal member improves the sealing performance of the drain hole during normal use of the fluid filter. be able to. In addition, the second restricting portion and the elastic support portion can be provided on the outer peripheral side of the drain bolt collar portion, and in the drain bolt collar portion, the vicinity of the male screw portion can be thickened, so that the drain bolt has a predetermined tightening torque. It is easy to secure the required strength.
In addition, a seal member is provided at the bottom of the cap so that the flange portion of the drain bolt is in pressure contact, and the first restricting portion is provided on the inner peripheral side of the seal member at the bottom of the cap. In the case where the second restricting portion is provided on the inner peripheral side of the portion of the flange portion of the drain bolt that is in pressure contact with the seal member, the seal member can improve the sealing performance of the drain hole during normal use of the fluid filter. Can be increased. In addition, since the first and second restricting portions are not exposed to the outside air by the sealing member, it is possible to prevent damage due to adhesion of dust or the like to both restricting portions.
Further, when each of the first restricting portion and the second restricting portion is a protrusion, when the drain bolt is screwed to the cap with a predetermined tightening torque, the second restricting portion is second with respect to the first restricting portion. The restricting part comes into contact and gets over, but the climbing period of the second restricting part with respect to the first restricting part, that is, the period during which pressure is applied to the second restricting part is instantaneous. It can be prevented more reliably and the drain bolt can be tightened or loosened without difficulty.
Further, when one of the first restricting portion and the second restricting portion is a protrusion and the other is a recess, when the drain bolt is screwed into the cap with a predetermined tightening torque, The first restricting portion and the second restricting portion are engaged. Therefore, both restricting portions can be positioned at a more accurate engagement position, and overtightening of the drain bolt can be prevented more reliably.

  The drain mechanism of the fluid filter according to the present embodiment includes a cap, a drain bolt, and a loosening restriction structure described below.

  As long as the “cap” is attached to the case and has a drain hole, its structure, shape, material and the like are not particularly limited. Examples of the material of the cap and the case include iron, aluminum, and resin.

The cap can be formed, for example, by inserting a metal insert member having a drain hole in which a female screw is formed on the inner periphery thereof into a resin cap body. In addition, the upper end part of an insert member is normally utilized as a metal seal of a drain hole.
At the bottom of the cap, for example, a seal member can be provided to which the flange of the drain bolt is pressed. Thereby, the sealing performance of the drain hole can be further enhanced.

  As long as the “drain bolt” is screwed into the cap with a predetermined tightening torque by relative rotation and closes the drain hole, its structure, shape, etc. are not particularly limited. This drain bolt is made of resin. Examples of the resin include polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PCV), acrylic resin (PMMA), polystyrene terephthalate (PET), polyacetal (POM), and polycarbonate (PC). And polyamide (PA) (nylon and the like).

  The drain bolt has, for example, a male screw portion that is screwed into a female screw portion formed on the inner peripheral side of the drain hole, and a collar portion that is continuous with the male screw portion and contacts the bottom portion of the cap. Can be. On the outer peripheral side of the collar portion, for example, a grip portion for gripping and hand-tightening by an operator can be provided.

  The loosening restriction structure includes a first restriction part, a second restriction part, and an elastic support part described below.

  As long as the “first regulating portion” is provided on the cap, the shape, the number, the arrangement form, and the like are not particularly limited. The first restricting portion is usually provided integrally with the cap. Moreover, this 1st control part can be provided in the bottom part (including the above-mentioned insert member) of the cap which the collar part of the said drain bolt press-contacts, for example. Thereby, when the drain bolt is extracted from the drain hole, the state of the first restricting portion exposed at the bottom of the cap can be easily confirmed.

  As long as the “second restricting portion” is provided on the drain bolt and contacts or engages with the first restricting portion by relative rotation of the cap and the drain bolt, its shape, size, number, etc. are not particularly limited. The second restricting portion is usually provided integrally with the drain bolt. Moreover, this 2nd control part can be provided in the surface side of the collar part of the drain bolt which press-contacts to the bottom part of the said cap, for example. Thereby, a 2nd control part and an elastic support part can be provided in the surface side of the collar part of a drain bolt, and it can prevent the enlargement of a drain bolt and by extension loosening control structure.

As long as the “elastic support portion” is provided on the drain bolt and elastically supports the second restricting portion, the shape, the number, the arrangement form, etc. are not particularly limited. This elastic support portion is usually provided integrally with the drain bolt. Examples of the elastic deformation direction of the elastic support portion include the axial direction, the radial direction, and the circumferential direction of the drain bolt.
The elastic support part can be composed of, for example, a thin wall part and / or a hole part formed in the collar part of the drain bolt. There are no particular limitations on the shape, number, etc. of these thin portions and holes.

  Here, as an arrangement form of the first and second restricting portions, for example, (1) the first restricting portion is provided on the outer peripheral side of the seal member at the bottom of the cap, and the second restricting portion is a collar of the drain bolt. (2) The first restricting portion is provided on the inner peripheral side of the seal member at the bottom of the cap, and the second restricting portion is the collar portion of the drain bolt. The form etc. which are provided in the inner peripheral side of the site | part which press-contacts in a sealing member can be mentioned.

  As a combination of the shapes of the first restricting portion and the second restricting portion, for example, (1) each of the first restricting portion and the second restricting portion is a protrusion, and (2) the first restricting portion is a dent. (3) The first restricting portion is a protrusion, and the second restricting portion is a recess.

In the form (1), for example, when the first and second restricting portions rotate relative to the cap in the direction P1 of tightening the drain bolt, immediately before the drain bolt is screwed with a predetermined tightening torque. It can arrange | position so that it may contact | abut. As a result, the first and second restricting portions do not repeatedly come into contact with each other during the tightening of the drain bolt, so that the first and second restricting portions can be more reliably prevented from being damaged and the drain bolt can be tightened or loosened without difficulty.
In this case, just before the drain bolt is screwed with the predetermined tightening torque, the second restricting portion comes into contact with the first restricting portion and rides on, and the first time when the drain bolt is screwed with the predetermined tightening torque. The second restricting portion gets over the restricting portion and is located at a position where both restricting portions contact or approach each other (see FIG. 7).

  In the configurations (2) and (3), for example, when the first and second restricting portions rotate relative to the cap in the direction P1 for tightening the drain bolt, the drain bolt is screwed with a predetermined tightening torque. Can be arranged to engage when done. As a result, the first and second restricting portions are not repeatedly engaged during the tightening of the drain bolt, so that the breakage of the first and second restricting portions can be more reliably prevented and the drain bolt can be tightened or loosened without difficulty.

The first restricting portion and the second restricting portion are, for example, a first abutting surface that abuts against the other restricting portion when rotating in the direction P1 of tightening the drain bolt with respect to the cap, and a drain bolt with respect to the cap. And a second abutting surface that abuts against the other-side restricting portion when rotating in the loosening direction P2 (see FIGS. 7 and 9). In this case, it is preferable that the angle A formed by the first contact surface and the rotation direction P1 is set to be smaller than the angle B formed by the second contact surface and the rotation direction P2. When the drain bolt is rotated in the direction P1 to be tightened, it can be easily tightened even if the first contact surfaces are in contact with each other. On the other hand, when the drain bolt is rotated in the direction P2 to be loosened, This is because the drain bolt can be made difficult to loosen.
The angle A can be, for example, 10 to 50 degrees (preferably 20 to 40 degrees). The angle B can be, for example, 40 to 80 degrees (preferably 50 to 70 degrees).

  The loosening restriction structure includes, for example, two or more sets including a first restriction portion, a second restriction portion, and an elastic support portion, and the two or more sets are substantially equal along the circumferential direction of the drain bolt. Can be arranged at intervals. Thereby, since the loosening restriction and the overtightening restriction are uniformly performed along the circumferential direction of the flange portion of the drain bolt, the loosening and overtightening can be more reliably prevented.

  Hereinafter, the present invention will be described in detail with reference to the first and second embodiments with reference to the drawings. In this embodiment, an oil filter attached to a cylinder block (not shown) of an internal combustion engine is exemplified as the element exchange type filter.

Example 1
(1) Configuration of Oil Filter As shown in FIG. 1, the oil filter 1 according to the present embodiment is housed in a housing 4 composed of a synthetic resin case 2 and a cap 3 that can be engaged and disengaged with each other. The filter element 5 and the drain mechanism 7 are configured.

  An external thread portion 8 is formed on the outer peripheral surface of the cap 3 and an O-ring 9 is attached. An internal thread portion 10 is formed on the inner peripheral surface of the case 2. When the male screw portion 8 and the female screw portion 10 are screwed together and the case 2 and the cap 3 are engaged via the O-ring 9, the inside of the housing 4 is sealed so as to be kept liquid tight. . Inside the housing 4, the upper and lower end portions of the filter element 5 are sealed by the case protrusions 6 provided on the plate 12 and the case 2 by the urging force of the spring 11 via the sealing members 13 and 14. The oil is filtered by 5.

  A metal insert member 16 having a drain hole 15 having an internal thread 15a formed on the inner periphery thereof is insert-molded at the center of the bottom 3a of the cap 3. An annular cap projection 18 is provided at the upper end of the insert member 16. An O-ring 17 (illustrated as a “seal member” according to the present invention) is attached to the lower end of the bottom 3 a of the cap 3 so as to surround the drain hole 15.

  Next, the drain mechanism 7 will be described. As shown in FIG. 2, the drain mechanism 7 includes a drain bolt 20 made of synthetic resin, a valve member 21 made of metal, and a spring 11. The drain bolt 20 has a male screw portion 22 in which a male screw 22a is formed and a collar portion 23 connected to a lower portion of the male screw portion 22 (see FIGS. 3 and 4). On the outer peripheral side of the collar portion 23, a grip portion 24 is provided for gripping when the operator manually tightens. Then, when the male screw 22 a of the drain bolt 20 and the female screw 15 a of the drain hole 15 are screwed together and the drain bolt 20 is screwed into the drain hole 15, the flange portion 23 of the drain bolt 20 is pressed against the O-ring 17. Thus, the drain hole 15 is sealed.

  The valve member 21 is formed in a tray shape as a whole, and has a contact portion 25 that contacts the outer peripheral surface of the cap protrusion 18. The abutment portion 25 is normally abutted against the cap protrusion 18 by the biasing force of the spring 11, and the drain hole 15 is metal-sealed. Therefore, even if the drain bolt 20 is removed from the drain hole 15, only a small amount of residual oil inside the housing 4 flows out from the drain hole 15 to the outside.

  As shown in FIG. 2, a loosening restricting structure 30 is provided between the cap 3 and the drain bolt 20. The loosening restriction structure 30 includes a first restriction part 31, a second restriction part 32, and an elastic support part 33 described below.

  The said 1st control part 31 is the protrusion integrally molded by the bottom part 3a of the cap 3 with which the collar part 23 of the drain bolt 20 contact | abuts (refer FIG. 5). As shown in FIG. 7A, the first restricting portion 31 includes a first abutting surface 31 a that abuts on the second restricting portion 32 when rotating the cap 3 in the direction P <b> 1 for tightening the drain bolt 20. And a second abutment surface 31b that abuts against the second restricting portion 32 when the drain bolt 20 is rotated relative to the cap 3 in the loosening direction P2. An angle A formed by the first contact surface 31a and the rotation direction P1 is set to 30 degrees. The angle B formed by the second contact surface 31b and the rotation direction P2 is set to 60 degrees.

  As shown in FIGS. 3 to 5, the second restricting portion 32 is a protrusion integrally formed on the surface side of the flange portion 23 of the drain bolt 20 that contacts the bottom portion 3 a of the cap 3. As shown in FIG. 7A, the second restricting portion 32 includes a first abutting surface 32a that abuts on the first restricting portion 31 when rotating the cap 3 in the direction P1 for tightening the drain bolt 20. The second abutment surface 32b abuts on the first restricting portion 31 when the drain bolt 20 is rotated relative to the cap 3 in the loosening direction P2. An angle A formed by the first contact surface 32a and the rotation direction P1 is set to 30 degrees. The angle B formed by the second contact surface 32b and the rotation direction P2 is set to 60 degrees. In addition, the said 1st control part 31 and the 2nd control part 32 are arrange | positioned at the outer peripheral side of the O-ring 17 (refer FIG. 2).

  As shown in FIGS. 3 to 5, the elastic support portion 33 is composed of a flat fan-shaped thin portion 33 a formed on the surface side of the flange portion 23 of the drain bolt 20. The second restricting portion 32 is provided on the surface of the elastic support portion 33, and the second restricting portion 32 is elastically supported in the axial direction of the drain bolt 20 by the elastic support portion 33.

  In the present embodiment, the “elastic support portion” according to the present invention is exemplified by only the thin portion 33a. However, the present invention is not limited to this, and, for example, as shown in FIG. Alternatively, the elastic support portion 33 may be formed of the thin portion 33a and the hole portion 33b formed on the surface side of the surface 23, or may be formed of only the hole portion 33b.

(2) Operation of Oil Filter Next, the operation of the oil filter 1 will be described.
During normal use of the oil filter 1, as shown in FIG. 1, a drain bolt 20 is screwed to the drain hole 15 of the cap 3 via an O-ring 17 to seal the drain hole 15. Further, the drain hole 15 is metal-sealed by the contact between the valve member 21 and the cap protrusion 18. On the other hand, when replacing the filter element 5 or the like, first, the drain bolt 20 is removed from the drain hole 15. Next, a pipe-shaped drain jig (not shown) is inserted into the drain hole 15, and the valve member 21 is pushed up to release the metal seal. Then, the residual oil inside the housing 4 is discharged to the outside through the drain jig. Next, when the residual oil is completely discharged, the draining jig 30 is pulled out from the cap 3, the cap 3 is separated from the case 2, and the replacement work of the filter element 5 and the like is performed.

After the above replacement work, the cap 3 is screwed by rotating in the direction P1 in which the drain bolt 20 is tightened. At the final stage of screwing, as shown in FIG. 7A, the second restricting portion 32 of the drain bolt 20 faces the first restricting portion 31 of the cap 3. Thereafter, the drain bolt 20 is further tightened, and immediately before the flange portion 23 of the drain bolt 20 contacts the bottom portion 3a of the cap 3 and the drain bolt 20 reaches a predetermined tightening torque, the first contact of the first restricting portion 31 is achieved. The contact surface 31 a and the first contact surface 32 a of the second restricting portion 32 come into contact with each other, and the elastic support portion 33 is elastically deformed to be second with respect to the first restricting portion 31 as shown in FIG. The regulation part 32 gets on. Immediately thereafter, as shown in FIG. 7C, the applied pressure to the second restricting portion 32 is instantaneously released by the elasticity of the elastic support portion 33, and the second restricting portion 32 is moved relative to the first restricting portion 31. The climbing restricting portions 31 and 32 are located at positions close to or in contact with each other. At this time, the drain bolt 20 is in a state of being tightened with a predetermined appropriate tightening torque.
In addition, when removing the drain bolt 20 from the cap 3, the effect | action contrary to the above-mentioned fastening is implemented.

(3) Effects of Embodiment As described above, in the present embodiment, when the drain bolt 20 is rotated relative to the cap 3 in the direction P1 of tightening the drain bolt 20, the drain bolt 20 is screwed to the cap 3 with a predetermined tightening torque. When combined, the second restricting portion 32 gets over the first restricting portion 31 and is positioned at a position where the second restricting portion 32 comes into contact with or close to the first restricting portion 31, so that the drain bolt 20 is loosened with respect to the cap 3 from this state. Even if it tries to rotate to P2, it is controlled that drain bolt 20 loosens more than necessary by contact of the 1st and 2nd control parts 31 and 32. As a result, it is possible to prevent oil leakage due to loosening of the drain bolt 20. Further, the operator who manually tightens the drain bolt 20 feels that the second restricting portion 32 gets over the first restricting portion 31 due to the elasticity of the elastic support portion 33, and the tightening torque of the drain bolt 20 becomes appropriate. I can confirm that. As a result, excessive tightening of the drain bolt 20 can be prevented and damage to the drain bolt 20 can be prevented.

  In the present embodiment, the first restricting portion 31 is integrally formed on the bottom portion 3a of the cap 3 made of synthetic resin, and the second restricting portion 32 and the elastic support portion 33 are integrally formed on the drain bolt 20 made of synthetic resin. As a result, the loosening restriction structure 30 can be configured without increasing the number of parts.

  In the present embodiment, since the second restricting portion 32 is elastically supported by the elastic support portion 33, the pressure applied to the second restricting portion 32 is absorbed or diverged by the elastic support portion 33, and The breakage of the second restricting portions 31 and 32 can be prevented and the drain bolt 20 can be tightened or loosened without difficulty.

  Further, in this embodiment, the elastic support portion 33 is constituted by the thin portion 33a formed on the surface side of the collar portion 23 of the drain bolt 20, so that the elastic support portion easily deflects on the surface side of the collar portion 23 of the drain bolt 20. 33 can be set easily. Moreover, since the 1st control part 31 was provided in the bottom part 3a of the cap 3, when the drain bolt 20 is extracted from the drain hole 15, the state of the 1st control part 31 exposed by the bottom part 3a of the cap 3 can be confirmed easily. . Moreover, since the 2nd control part 32 and the elastic support part 33 were provided in the surface side of the collar part 23 of the drain bolt 20, the enlargement of the drain bolt 20 and the loose rotation control structure 30 can be prevented. Further, the second restricting portion 32 and the elastic support portion are provided even when the operator accidentally drops the drain bolt 20 as compared with the case where the second restricting portion 32 is provided protruding from the outer peripheral surface of the flange portion 23 of the drain bolt 20. 33 can be prevented from being damaged.

  In the present embodiment, the first and second restricting portions 31 and 32 are provided on the outer peripheral side of the O-ring 17, so that the elastic support portion 33 is provided on the outer peripheral side of the flange portion 23 of the drain bolt 20. In the flange 23 of the drain bolt 20, the vicinity of the male screw portion 22 can be thickened, and it is easy to ensure the strength necessary for a predetermined tightening torque of the drain bolt 20.

  In the present embodiment, since each of the first and second restricting portions 31 and 32 is a projection, when the drain bolt 20 is screwed to the cap 3 with a predetermined tightening torque, the first restricting portion 31 is used. On the other hand, the period during which the second restricting portion 32 rides, that is, the period during which the second restricting portion 32 is pressurized is instantaneous, and the breakage of the restricting portions 31, 32 can be prevented more reliably and the drain bolt 20 can be installed. It can be tightened or loosened without difficulty.

  Further, in the present embodiment, when the first and second restricting portions 31 and 32 are rotated relative to the cap 3 in the direction P1 of tightening the drain bolt 20, the drain bolt 20 is screwed with a predetermined tightening torque. Since the first and second restricting portions 31 and 32 do not repeat contact when the drain bolt 20 is tightened, the both restricting portions 31 and 32 are more reliably damaged. The drain bolt 20 can be tightened or loosened with ease. Moreover, it can confirm more reliably that the fastening torque of the drain bolt 20 became appropriate.

  In the present embodiment, the angle A formed by the first contact surfaces 31a, 32a of the first and second restricting portions 31, 32 and the rotation direction P1 is set to the second of the first and second restricting portions 31, 32. Since a value smaller than the angle B formed by the contact surfaces 31b and 32b and the rotation direction P2 is set, even when the first contact surfaces 31a and 32a contact each other when the drain bolt 20 is rotated in the direction P1. On the other hand, when the drain bolt 20 is rotated in the loosening direction P2, the drain bolt 20 can be hardly loosened by the contact between the second contact surfaces 31b and 32b.

(Example 2)
Next, a drain mechanism according to Embodiment 2 will be described. Note that the drain mechanism according to the second embodiment will not be described in detail with respect to substantially the same configuration and effect as the drain mechanism 30 of the first embodiment.

(1) Configuration of Drain Mechanism The drain mechanism 7A according to the second embodiment includes a loosening restriction structure 40 as shown in FIG. The loosening restriction structure 40 includes a first restriction part 41, a second restriction part 42, and an elastic support part 33. The first restricting portion 41 is a recess formed integrally with the bottom portion 3a of the cap 3 with which the flange portion 23 of the drain bolt 20 abuts. The second restricting portion 42 is a protrusion integrally formed on the surface side of the flange portion 23 of the drain bolt 20 that contacts the bottom portion 3a of the cap 3.

(2) Action and effect of loosening restricting structure After replacing the filter element 5 and the like, as shown in FIG. 9A, the cap 3 is screwed in the direction P1 in which the drain bolt 20 is tightened. . At the final stage of screwing, as shown in FIG. 9B, the second restricting portion 42 of the drain bolt 20 is pressed against the bottom 3a of the cap 3 and the elastic support portion 33 is elastically deformed. Thereafter, when the drain bolt 20 is further tightened, the applied pressure to the second restricting portion 42 is instantaneously released by the elasticity of the elastic support portion 33 as shown in FIG. A protrusion which is the second restricting portion 42 enters the recess, and the first and second restricting portions 41 and 42 are engaged with each other. At this time, the drain bolt 20 is in a state of being tightened with a predetermined appropriate tightening torque.

  Therefore, even if the drain bolt 20 tries to rotate in the loosening direction P2 with respect to the cap 3 from this state, the drain bolt 20 is restricted from being loosened more than necessary due to the engagement of the first and second restricting portions 41 and 42. Is done. Further, the operator who manually tightens the drain bolt 20 confirms that the tightening torque of the drain bolt 20 is appropriate due to the feeling that the first and second restricting portions 41 and 42 are engaged by the elasticity of the elastic support portion 33. This can be confirmed, and excessive tightening of the drain bolt 20 can be prevented to prevent the drain bolt 20 from being damaged.

  In the present embodiment, the first restricting portion 41 is a recess and the second restricting portion 42 is a protrusion that enters the recess, so that the first and second restricting portions 41 and 42 can be positioned at more accurate engagement positions. Further, the over tightening of the drain bolt 20 can be prevented more reliably.

  Further, in the present embodiment, when the first and second restricting portions 41 and 42 are rotated relative to the cap 3 in the direction P1 of tightening the drain bolt 20, the drain bolt 20 is screwed with a predetermined tightening torque. Since the first and second restricting portions 41 and 42 are not repeatedly engaged and disengaged when the drain bolt 20 is tightened, both the restricting portions 41 and 42 are more reliably prevented from being damaged. In addition, the drain bolt 20 can be tightened or loosened without difficulty. Moreover, it can confirm more reliably that the fastening torque of the drain bolt 20 became appropriate.

  In the present invention, the present invention is not limited to the first and second embodiments, and various modifications can be made within the scope of the present invention depending on the purpose and application. That is, in the first and second embodiments, the first restricting portions 31 and 41 are provided on the bottom 3a of the cap 3 on the outer peripheral side of the O-ring 17 and the second restricting portion on the outer peripheral side of the flange portion 23 of the drain bolt 20. However, the present invention is not limited thereto. For example, as shown in FIG. 10, the first restricting portion 31, the bottom portion 3 a of the cap 3 on the inner peripheral side of the O-ring 17, that is, the insert member 16, 41 and the second restriction portions 32 and 42 may be provided on the inner peripheral side of the flange portion 23 of the drain bolt 20. In this case, the first restricting portions 31 and 41 and the second restricting portions 32 and 42 are not exposed to the outside air by the O-ring 17, so that damage due to adhesion of dust or the like to both the restricting portions 31, 41, 32, 42, etc. Can be prevented.

  In the first and second embodiments, the first restricting portions 31 and 41 are provided on the bottom portion 3a of the cap 3 to which the flange portion 23 of the drain bolt 20 is pressed. However, the present invention is not limited to this. As shown in FIG. 1, the first restricting portions 31 and 41 may be provided on the bottom portion 47 of the cap 3 where the flange portion 23 of the drain bolt 20 is not pressed.

  Moreover, in the said Example 1 and 2, although the elastic support part 33 elastically deformed to the axial direction of the drain bolt 20 was illustrated, it is not limited to this, For example, as shown in FIG. 12, the radial direction of the drain bolt 20 Alternatively, the elastic support portion 34 may be elastically deformed, or the elastic support portion 35 may be elastically deformed in the circumferential direction of the drain bolt 20.

  Moreover, in the said Example 1 and 2, although the 2nd control parts 32 and 42 were provided in the collar part 23 of the drain bolt 20, it is not limited to this, For example, the top of the external thread part 22 of the drain bolt 20 You may make it provide the 2nd control part 32 and 42 in the side. In this case, the first restricting portions 31 and 41 are disposed on the upper end side of the insert member 16.

  Moreover, in the said Example 1 and 2, although only one set of a pair of 1st and 2nd control parts 31 and 32 (41, 42) was provided, it is not limited to this, For example, a pair of 1st and 2nd You may make it provide two or more sets of 2nd control parts 31 and 32 (41, 42). In this case, as indicated by phantom lines in FIG. 2, a plurality of sets (two sets in the figure) are preferably arranged at equal intervals along the circumferential direction of the drain bolt 20.

  Moreover, in the said Example 1 and 2, although the synthetic resin cap 3 formed by insert-molding the metal insert member 16 was illustrated, it is not limited to this, For example, the insert member 16 is stopped and all synthetic resin It is good also as a cap which consists of.

  Furthermore, in the said Example 2, although the 1st control part 41 was made into the dent and the 2nd control part 42 was made into the protrusion, it is not limited to this, For example, the 1st control part 41 is made into the protrusion and the 2nd control part 42 It is good also as a dent.

  It is widely used in oil filters, fuel filters and related fields for filtering foreign matters, wear powder, carbon and the like mixed in oil for lubricating an internal combustion engine.

1 is a longitudinal sectional view showing an oil filter according to Embodiment 1. FIG. 1 is a longitudinal sectional view showing a drain mechanism according to Embodiment 1. FIG. It is a front view which shows a drain bolt. It is IV arrow line view of FIG. It is a perspective view which shows a drain bolt and a cap. It is a perspective view which shows the drain bolt of other forms. It is explanatory drawing for demonstrating the effect | action of the loosening rotation control structure which concerns on Example 1. FIG. 6 is a longitudinal sectional view showing a drain mechanism according to Embodiment 2. FIG. It is explanatory drawing for demonstrating the effect | action of the loosening rotation control structure which concerns on Example 2. FIG. It is a longitudinal cross-sectional view which shows the loosening rotation control structure of another form. Furthermore, it is a longitudinal cross-sectional view which shows the loosening rotation control structure of another form. It is a top view which shows the drain bolt of other forms.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1; Oil filter, 3; Cap, 3a; Bottom part, 7 and 7A; Drain mechanism, 15: Drain hole, 17; O-ring, 20; Drain bolt, 23: Collar part, 30, 40; , 41; first restricting portion, 32, 42; second restricting portion, 33, 34, 35; elastic support, 33a; thin wall portion, 33b;

Claims (5)

In a drain mechanism of a fluid filter, comprising: a cap attached to a case and having a drain hole; and a drain bolt screwed with a predetermined tightening torque by relative rotation with the cap to close the drain hole.
The drain bolt is made of resin,
A first restricting portion provided on the cap; a second restricting portion provided on the drain bolt and contacting or engaging the first restricting portion by relative rotation of the cap and the drain bolt; and the drain bolt An elastic support portion provided and elastically supporting the second restricting portion ;
The fluid filter drain mechanism according to claim 1, wherein the elastic support portion includes a thin wall portion and / or a hole portion formed in a flange portion of the drain bolt . The bottom of the cap is provided with a seal member to which the flange of the drain bolt is pressed, and the first restricting portion is provided on the outer peripheral side of the seal member at the bottom of the cap. 2. The drain mechanism of the fluid filter according to claim 1 , wherein the restriction portion is provided on an outer peripheral side of a portion of the flange portion of the drain bolt that is in pressure contact with the seal member . The bottom of the cap is provided with a seal member to which the flange of the drain bolt is pressed, and the first restricting portion is provided on the inner peripheral side of the seal member at the bottom of the cap, The fluid filter drain mechanism according to claim 1 , wherein the second restricting portion is provided on an inner peripheral side of a portion of the flange portion of the drain bolt that is in pressure contact with the seal member . The first restricting portion and each of said second restricting portion fluid filter of the drain mechanism according to any one of claims 1 to 3 is a projection. The first restricting portion and one of said second restricting portion is projections and the other fluid filter drain mechanism according to any one of claims 1 to 3 is recessed to projecting Kiga engagement.

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