JP2018084301A - Oil seal and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil seal which eliminates a need of performing processing for reducing a frictional force to a movable shaft, increases the efficiency of maintenance work of the movable shaft, and enables reduction of movable torque of the movable shaft.SOLUTION: The invention relates to an oil seal 4 provided between a housing 3, which houses a mechanical motion mechanism part including a movable shaft 10 and a lubrication oil, and the movable shaft 10 and inhibiting leakage of the lubrication oil housed in the housing and a manufacturing method of the oil seal 4. The oil seal 4 includes: a metal ring 5 detachably attached to one of the housing 3 and the movable shaft 10; and a seal body part 6 having seal lips 81, 82, which slidably contact with the metal ring 5, and attached to the other of the housing 3 and the movable shaft 10. The metal ring 5 includes low friction surfaces 511, 521 which are formed having roughness that reduces a frictional force caused by slide contact of the seal lips 81, 82.SELECTED DRAWING: Figure 1

Description

  The present invention is provided between a movable shaft and a mechanical motion mechanism including a movable shaft, such as an automobile engine, a geared motor, or a pump, and a housing that contains lubricating oil, and is accommodated in the housing. The present invention relates to an oil seal that suppresses leakage of the lubricating oil and a manufacturing method thereof.

  An oil pan or a crankcase (hereinafter, generically referred to as an oil pan for convenience) in which a mechanical motion mechanism such as a connecting rod connected to a piston and a crankshaft is housed is installed at a lower portion of a cylinder block in an automobile engine. In the oil pan, lubricating oil is accommodated in order to smoothly move the friction portions of the mechanical motion mechanism. A part of the crankshaft (rotary shaft) is led out from the combined portion of the cylinder block and the oil pan and connected to the drive transmission mechanism and the like. An oil seal is mounted between the cylinder block, the oil pan, and the crankshaft in the crankshaft lead-out portion of the mating portion. This oil seal prevents external leakage of the lubricating oil from the housing constituted by the cylinder block and the oil pan, and prevents intrusion of dust and the like from the outside into the housing. As such an oil seal, for example, an oil seal as shown in FIG. 4 is used.

  The oil seal 110 shown in FIG. 4 is attached to the lead-out portion of the crankshaft 120 at the mating portion of the oil pan 100 and the cylinder block 200. The lead-out portion of the crankshaft 120 is formed with a through hole 101 communicating with the inside 300 </ b> A of the housing 300 constituted by the oil pan 100 and the cylinder block 200 and the outside 300 </ b> B. The crankshaft 120 is inserted into the through hole 101 from the inside 300A of the housing 300, and a part of the crankshaft 120 is led out as a rotation output shaft to the outside 300B. The oil seal 110 is mounted between the hole wall 101 a on the oil pan 100 side and the hole wall 101 b on the cylinder block 200 side of the through hole 101 and the outer peripheral surface 120 a of the crankshaft 120. The housing 300 accommodates a connecting rod connected to a piston (not shown), a mechanical motion mechanism such as a crankshaft 120, and lubricating oil. The crankshaft 120 rotates about the axis L by the mechanical motion mechanism.

The oil seal 110 includes a core metal 115 fitted to the hole walls 101a and 101b of the through hole 101 via an elastic body 111, an elastic body 111 fixed integrally to the core metal 115, and a series of two seal lips. 112 and 113, and a garter spring 114 for urging the seal lip 112 in the diameter reducing direction. The core metal 115 extends from the cylindrical portion 116 fitted to the hole walls 101a and 101b of the through hole 101 via the elastic body 111 and the inner side (the inner 300A side) end portion 116a of the cylindrical portion 116 toward the inner diameter side. It is composed of a bent hook-shaped portion 117 which is taken out. The elastic body 111 wraps around the outer peripheral surface 116b of the cylindrical portion 116, the entire inner side surface 117a of the bent hook-shaped portion 117 and the inner diameter side end portion 117b of the bent hook-shaped portion 117 so as to cover a part of the outer side surface 117c. It is fixed to the core metal 115. The two seal lips 112 and 113 are formed in series so that the front side portions thereof are opposite to each other in the axis L direction. The seal lips 112 and 113 are configured such that their tip portions elastically contact the outer peripheral surface 120a of the crankshaft 120, and elastically slidably contact the outer peripheral surface 120a of the crankshaft 120 by rotation around the axis L of the crankshaft 120. . The seal lip 112 facing the interior 300 </ b> A side of the housing 300 mainly suppresses external leakage of the lubricating oil in the housing 300. On the other hand, the seal lip 113 facing the outside 300 </ b> B mainly functions to suppress external dust from reaching the seal lip 112.
Normally, a bearing that supports the crankshaft 120 so as to be axially rotatable is often attached to the cylinder block 200 in the vicinity of one of the oil seals 110 in the axis L direction. Omitted (hereinafter the same).

  In Patent Document 1 and Patent Document 2, a sleeve (slinger) having a substantially L-shaped cross section is fitted to the movable shaft, a seal body having a plurality of seal lips is attached to the housing, and the seal lip is a sleeve (slinger). A sealing device configured to slidably contact is described. Further, Patent Document 3 describes a sealing device that is mainly used in a vehicle bearing device and is configured by combining a slinger and a seal member having a seal lip that is in sliding contact with the slinger elastically. Has been. And this patent document 3 also describes that surface treatment is performed on the sliding contact surface of the slinger with the seal lip to reduce the frictional force caused by the sliding contact with the seal lip, thereby reducing the rotational torque.

JP 2005-16535 A JP 2005-273864 A JP 2010-78140 A

  By the way, in the case of the oil seal as shown in FIG. 4, the front ends of the seal lips 112 and 113 are in direct contact with the outer peripheral surface 120 a of the crankshaft 120. Therefore, the frictional force between the crankshaft 120 and the seal lips 112 and 113 accompanying the shaft rotation of the crankshaft 120 is large, which becomes a factor for increasing the rotational torque of the crankshaft 120. The sealing devices described in Patent Document 1 and Patent Document 2 are also expected to contain the problem of frictional resistance on the sliding contact surface between the seal lip and the sleeve (slinger). 2 does not suggest solving such a problem. On the other hand, in patent document 3, the structure which solves such a subject in a sealing device is proposed. However, the sealing device of Patent Document 3 mainly seals a bearing space filled with a highly viscous lubricant such as grease, and is suitable as an oil seal that suppresses leakage of lubricating oil with low viscosity. It is not certain whether or not it has.

  The present invention has been made in view of the above circumstances, and eliminates the need to perform a process for reducing the frictional force on the movable shaft, thereby improving the efficiency of the maintenance work of the movable shaft and reducing the movable torque of the movable shaft. It is an object of the present invention to provide an oil seal that can be used and a method for manufacturing the same.

  An oil seal according to a first invention of the present application is provided between a mechanical motion mechanism section including a movable shaft and a housing for accommodating lubricating oil and the movable shaft, and prevents leakage of the lubricating oil accommodated in the housing. An oil seal for restraining, comprising a metal ring that is detachably attached to one of the housing and the movable shaft, and a seal that is attached to the other of the housing and the movable shaft by having a seal lip that is in sliding contact with the metal ring. And a metal ring, wherein the metal ring includes a low friction surface formed to have a roughness that reduces a frictional force caused by sliding contact of the seal lip.

  According to the oil seal of the present invention, the seal lip of the seal body attached to the other of the housing and the movable shaft is in sliding contact with the metal ring attached to one of the housing and the movable shaft. The leakage of the lubricating oil that is sealed and accommodated in the housing is suppressed. Further, the surface of the metal ring on which the seal lip is slidably contacted is a low friction surface formed with a roughness that reduces the frictional force caused by the slidable contact, so that the movable torque of the movable shaft can be reduced. Since the metal ring with which the seal lip is in sliding contact is detachable with respect to the attachment target, the efficiency of the maintenance work can be improved as compared with the case where the movable shaft is processed. In particular, in the case of an oil seal, in order to exhibit sufficient performance, it is required to appropriately manage the roughness of the surface on which the seal lip slides. However, since the metal ring is detachable, such a slide is required. Proper management of the roughness of the contact surface is facilitated.

In the oil seal of the present invention, the movable shaft is a rotating shaft, and the metal ring includes a cylindrical portion attached to one of the housing and the rotating shaft, and a flange extending in a radial direction from one axial end portion of the cylindrical portion. The seal lip includes a main seal lip that is slidably in contact with the cylindrical portion, and a sub-seal lip that is in slidable contact with the flange portion, and the main seal lip is disposed closer to the housing than the sub-seal lip. The secondary seal lip is arranged on the outer side of the main seal lip so as to prevent external dust from reaching the main seal lip. The slidable contact surface with which the main seal lip is slidably contacted may be the low friction surface formed with a roughness that reduces the frictional force.
According to this, external leakage of the lubricating oil in the housing is suppressed by the main seal lip, and dust from the outside is suppressed from reaching the main seal lip by the sub seal lip. In this way, by suppressing the arrival of dust to the main seal lip, it is possible to reduce the occurrence of dust biting between the main seal lip and the metal ring, thereby suppressing wear of the main seal lip and sealing. The service life is extended. In addition, the rotational torque of the rotating shaft generated by the oil seal is easily affected by the sliding contact state between the main seal lip and the sliding surface of the cylindrical portion of the metal ring, which is a radial surface. Therefore, the rotational torque can be appropriately reduced.

In the oil seal of the present invention, the slidable contact surface of the flange portion with which the secondary seal lip is slidably contacted is a low friction surface formed to have a roughness that reduces frictional force due to the slidable contact of the secondary seal lip. It is good.
According to this, since the sliding contact surface of the flange portion as well as the sliding contact surface of the cylinder portion is formed to have a roughness that reduces the frictional force, the rotational torque can be reduced more appropriately.

In the oil seal of the present invention, the sub seal lip may have a concavo-convex portion formed in a roughness range that allows ventilation at a distal end portion that is in sliding contact with the flange portion.
According to this, since the space between the sub seal lip and the main seal lip is easily ventilated to the outside of the housing, it is difficult for the space between the sub seal lip and the main seal lip to have a negative pressure. As a result, it is possible to prevent the lubricating oil to be sealed by the main seal lip from being drawn between the main seal lip and the sub seal lip, and thus to suppress the deterioration of the sealing performance.

In the oil seal of the present invention, the low friction surface of the metal ring may be a plateau structure surface having oil film retention.
According to this, the trough part formed in a low friction surface functions as an oil sump. Accordingly, it is possible to suppress the loss of the oil film between the seal lip and the low friction surface, and it is possible to avoid the sliding contact portion of the seal lip from being caught on the peak portion of the low friction surface, thereby further reducing the friction force.
In this case, the width of the opening of the valley portion of the plateau structure surface may be smaller than the sliding contact width of the seal lip with respect to the plateau structure surface.
According to this, since the sliding contact portion of the seal lip covers the opening of the valley portion of the plateau structure surface, a passage leading to the inside and outside of the sliding contact portion of the seal lip through the valley portion cannot be formed, and the sealing performance is deteriorated. This can be suppressed.

In the oil seal of the present invention, the roughness for reducing the frictional force may be set in a range of 0.1 to 0.6 μmRa.
According to this, the performance as the oil seal can be secured while reducing the torque of the movable shaft. Incidentally, when the roughness of the sliding contact surface is less than 0.1 μmRa, the effect of reducing the frictional force tends not to be obtained sufficiently, while when the roughness of the sliding contact surface is larger than 0.6 μmRa, The sealing performance tends to decrease.

  According to a second aspect of the present invention, there is provided a method for manufacturing an oil seal, comprising: a mechanical motion mechanism including a movable shaft; a housing for housing lubricating oil; and the movable shaft, the lubricating oil housed in the housing. The oil seal includes a metal ring that is detachably attached to one of the housing and the movable shaft, and a seal lip that is in sliding contact with the metal ring. A seal body attached to the other of the housing and the movable shaft, blasting the slidable contact surface of the metal ring with which the seal lip is slidably contacted, and slidably contacting the slidable contact surface with the seal lip It is characterized by having a low friction surface set to a roughness that reduces the frictional force due to.

  According to the method of manufacturing an oil seal of the present invention, the sliding contact surface with which the seal lip in the metal ring comes into sliding contact is a low friction surface set to a roughness that reduces the frictional force by blasting. An oil seal with a reduced movable torque can be manufactured.

  According to the oil seal and the method of manufacturing the oil seal of the present invention, it is not necessary to perform a process for reducing the frictional force on the movable shaft, thereby improving the efficiency of maintenance work of the movable shaft and reducing the movable torque of the movable shaft. can do.

It is one Embodiment of the oil seal which concerns on this invention, Comprising: It is the partial fracture | rupture longitudinal cross-sectional view which shows typically the state with which the mounting object was mounted | worn with an enlarged part. It is a modification of the oil seal of the embodiment, Comprising: It is a partially broken longitudinal cross-sectional view which shows the state with which the mounting object was mounted | worn typically with an enlarged part. It is another embodiment of the oil seal which concerns on this invention, Comprising: It is a figure similar to FIG. It is a figure similar to FIG. 1 which shows the example of the conventional oil seal.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a joint portion between an oil pan 1 and a cylinder block 2 in an automobile engine. The oil pan 1 is fastened and integrally attached to a lower end portion of the cylinder block 2 by a bolt (not shown). The oil pan 1 and the cylinder block 2 are connected to a mechanical motion mechanism portion (not shown) including a movable shaft and a lubricating oil (same as above). ) Is configured. A through hole 30 for leading out the crankshaft 10 as a movable shaft is formed in the mating portion. The through hole 30 includes a semicircular hole wall 30a formed on the oil pan 1 side and a semicircular hole wall 30b formed on the cylinder block 2 side. The crankshaft 10 is connected to a piston (both not shown) via a connecting rod and a piston pin, and the vertical reciprocation of the piston is converted into rotation around the axis L of the crankshaft 10 (shaft rotation), thereby mechanical movement. The mechanism part is configured. The crankshaft 10 is supported by the cylinder block 2 through a bearing (not shown) so as to be rotatable about the shaft, and is led out from the through hole 30 as an output shaft.

  The oil seal 4 according to the present embodiment is provided between the mechanical motion mechanism including the crankshaft 10 and the housing 3 housing the lubricating oil and the crankshaft 10, and the lubricating oil stored in the housing 3. This prevents the leakage of water. Specifically, the oil seal 4 of this embodiment has a metal ring 5 that is detachably attached to the crankshaft 10 (one of the housing and the movable shaft), and seal lips 81 and 82 that elastically contact the metal ring 5. And a seal body 6 attached to the housing 3 (the other of the housing and the movable shaft). The metal ring 5 includes low friction surfaces 511 and 521 formed at a portion where the seal lips 81 and 82 are in sliding contact with each other so as to reduce the frictional force caused by the sliding contact. The metal ring 5 and the seal main body 6 both have a substantially L-shaped cross section, and are combined so that the L-shaped shapes face each other. A portion between the housing 3 and the crankshaft 10 in the through hole 30. Assembled to. More specifically, the seal body 6 is assembled along the axis L direction so that the seal body 6 is positioned on the inner 3A side of the housing 3 and the metal ring 5 is positioned on the outer 3B side of the housing 3. In a state where the metal ring 5 and the seal body 6 are combined, the closest radial contact between the elastic body 50 described later covered by the metal ring 5 and the seal body 8 described later constituting the seal body 6. A labyrinth r1 that suppresses intrusion of dust from the outside 3B is formed in the portion.

  The metal ring 5 includes a cylindrical portion (cylinder portion) 51 and a flange portion 52 that extends from the outer 3B side end portion (axial end portion) 51a of the cylindrical portion 51 in the outer radial direction (radial direction). The inner peripheral surface 51b of the cylindrical portion 51 of the metal ring 5 and the one surface 52a facing the outside 3B side of the flange portion 52 continuous thereto are covered with an elastic body 50 such as rubber. The elastic body 50 is integrally molded by being vulcanized and bonded to the metal ring 5. Hereinafter, a portion of the elastic body 50 that covers the cylindrical portion 51 of the metal ring 5b is referred to as a first covering portion 50a, and a portion that covers one surface 52a of the flange portion 52 is referred to as a second covering portion 50b. In addition, the 1st coating | coated part 50a is formed so that it may wrap around to the edge part by the side of the inside 3A of a cylindrical part. The second covering portion 50 b is formed so as to go around to the outer diameter side end portion of the flange portion 52. The cylindrical portion 51 in the metal ring 5 is fitted to the outer peripheral surface 10a of the crankshaft 10 with the first covering portion 50a of the elastic body 50 interposed therebetween. This fitting is performed in a state where the first covering portion 50a is in an elastically compressed state, whereby the fitting portion between the metal ring 5 and the crankshaft 10 is sealed.

  The seal body 6 includes a cylindrical part 71 and a cored bar 7 including an inward flange part 72 extending from the inner 3A side one end 71a of the cylindrical part 71 to the inner diameter side, and an elastic body such as rubber having the seal lips 81 and 82. The seal body 8 is provided. The seal body 8 is fixed to the core metal 7 so as to cover the inner and outer peripheral surfaces 71b and 71c of the cylindrical portion 71 of the core metal 7 and the one surface 72a facing the outside 3B side of the inward flange portion 72, and the seal lips 81 and 82 are The tip of the seal body 8 is formed so as to elastically contact a predetermined portion of the metal ring 5. Hereinafter, a portion of the seal body 8 that covers the outer peripheral surface 71c of the cylindrical portion 71 of the core metal 7 is referred to as a third covering portion 8a, and a portion that covers the inward flange portion 72 is referred to as a fourth covering portion 8b. The cylindrical portion 71 of the metal core 7 is fitted into the hole wall 30a on the oil pan 1 side and the hole wall 30b on the cylinder block 2 side with the third covering portion 8a of the seal body 8 interposed. This fitting is performed in a state where the third covering portion 8a is elastically compressed, whereby the fitting portion between the cored bar 7 and the through hole 30 is sealed.

  The seal lip 81 is a main seal lip whose tip is reduced in diameter toward the inside 3 </ b> A side of the housing 3 and suppresses leakage of the lubricating oil in the housing 3, and the cylindrical portion 51 in the metal ring 5. This is a radial lip that elastically contacts the outer peripheral surface 51c. A garter spring 83 that elastically urges the distal end portion of the main seal lip 81 so as to tighten the distal end portion in the diameter-reducing direction is externally covered. The low friction surface 511 is formed on at least a portion of the outer peripheral surface 51c of the cylindrical portion 51 where the main seal lip 81 is elastically contacted. The seal lip 82 is a sub-seal lip that is disposed on the outer 3B side of the main seal lip 81 and has a shape that prevents dust from the outer 3B from reaching the main seal lip 81. The auxiliary seal lip 82 is an axial lip whose tip end is expanded toward the outside 3B side of the housing 3 and elastically contacts the other surface 52b of the flange portion 52 of the metal ring 5 facing the inside 3A. The low friction surface 521 is formed on at least a portion of the other surface 52b of the flange portion 52 where the sub seal lip 82 is elastically contacted. Grease for lubrication is supplied between the sub seal lip 82 and the low friction surface 521. Both the main seal lip 81 and the sub seal lip 82 are elastically contacted with the metal ring 5 with an allowance, and are configured to relatively elastically contact with the rotation of the crankshaft 10. The two-dot chain line of the enlarged portion in FIG. 1 indicates the original shape of the main seal lip 81 and the sub seal lip 82 before elastic deformation. In the present embodiment, a plurality of concavo-convex portions 82 a that repeat at appropriate intervals in the circumferential direction are further formed at the distal end portion of the sub seal lip 82. Since the sub seal lip 82 only needs to be able to suppress the intrusion of dust, the uneven portion 82a formed on the sub seal lip 82 vents between the front and back of the sub seal lip 82 even in the elastic contact state with the flange portion 52 in the metal ring 5. Is formed in an allowable roughness range. Specifically, the sub seal lip 82 is formed so that the tip end portion has a roughness of 0.5 to 5.0 μmRa.

  The low friction surfaces 511 and 521 are formed by blasting the outer peripheral surface 51 of the cylindrical portion 51 and the other surface 52 b of the flange portion 52 in the metal ring 5. Specifically, the target surface is formed by blasting a substantially spherical medium having a particle diameter of 20 to 200 μm at an injection speed of 100 m / sec or more. The obtained low friction surface is formed to have a roughness of 0.1 to 0.6 μmRa to reduce the friction. The low friction surface is formed such that the protruding valley depth Rvk defined by JIS B 0671-2 is 0.08 μm or less, and the top portions of the peak portions 511a and 521a are flat plateau structure surfaces. The low friction surface in this roughness range is a rough surface suitable for the purpose of reducing the frictional force caused by the sliding contact between the main seal lip 81 and the sub seal lip 82. Further, the widths (diameters) d1 and d2 of the openings of the valley portions 511b and 521b in the plateau structure surfaces of the low friction surfaces 511 and 521 are the sliding contact widths D1 of the main seal lip 81 and the sub seal lip 82 with respect to the metal ring 5, respectively. , Smaller than D2. The “width of the opening of the valley portion” means a width along the same direction as the sliding contact width in the opening of each valley portion. More specifically, the low friction surface 511 of the present embodiment has a width along the direction parallel to the axis L, while the low friction surface 521 of the present embodiment is parallel to the low friction surface 521 and The width is along the direction orthogonal to the axis L.

  In the housing 3 to which the oil seal 4 configured as described above is applied, when the crankshaft 10 is axially rotated by the operation of the mechanical motion mechanism portion, the tip portion of the main seal lip 81 becomes the cylindrical portion 51 in the metal ring 5. The outer peripheral surface 51 is elastically slidably contacted. By this relative sliding contact, leakage of the lubricant accommodated in the housing 3 to the outside 3B side is suppressed. Further, the distal end portion of the sub seal lip 82 is elastically slidably contacted with the other surface 52 b of the flange portion 52 in the metal ring 5. Due to this relative sliding contact, the dust from the outside 3 </ b> B is prevented from reaching the sliding contact portion of the main seal lip 81. In this way, the arrival of dust at the tip of the main seal lip 81 is suppressed, so that it is possible to reduce the occurrence of dust biting between the main seal lip 81 and the metal ring 5. The wear of the tip portion of 81 is suppressed, and the life of the sealing function is extended. In this case, the rotational torque of the crankshaft 10 generated in the oil seal 4 is influenced by the sliding contact state between the outer peripheral surface 51 c (sliding contact surface) of the cylindrical portion 51 of the metal ring 5 that is a radial surface and the main seal lip 81. Easy to receive. However, since the outer peripheral surface 51c of the cylindrical portion 51 is the low friction surface 511, the rotational torque can be appropriately reduced. In addition, since the garter spring 83 is attached to the main seal lip 81, the state in which the main seal lip 81 is elastically slidably contacted with the cylindrical portion 51 of the metal ring 5 is stably maintained.

  Since the low friction surfaces 511 and 521 of the metal ring 5 are set in a roughness range of 0.1 to 0.6 μmRa, the frictional force between the main seal lip 81 and the sub seal lip 82 and the metal ring 5 is low. It is optimized. Thereby, the performance as the oil seal 4 can be ensured while reducing the torque of the crankshaft 10. Further, since the low friction surface 511 of the metal ring 5 is a plateau structure surface having oil film retaining property, a trough portion 511b formed in the low friction surface 511 is stored in the housing of the lubricating oil accommodated in the housing 3. Function as. Therefore, it is possible to prevent the oil film between the main seal lip 81 and the low friction surface 511 from disappearing. Further, since the low friction surface 521 of the metal ring 5 is a plateau structure surface having oil film retention, the valley portion 521b formed on the low friction surface 521 functions as a grease reservoir. Accordingly, it is possible to prevent the grease between the sub seal lip 82 and the low friction surface 521 from being lost. In addition, it is possible to prevent the sliding portions of the main seal lip 81 and the sub seal lip 82 against the metal ring 5 from being caught on the peak portions 511a and 521a of the low friction surfaces 511 and 521, thereby further reducing the frictional force. Further, since the widths d1 and d2 of the openings of the valley portions 511b and 521b on the plateau structure surface are formed smaller than the sliding widths D1 and D2 of the seal lips 81 and 82, the sliding contact of the seal lips 81 and 82 is achieved. The opening covers the valley portions 511b and 521b. Thereby, the passage which leads to the inside and outside of the sliding contact part of the seal lips 81 and 82 via the valley parts 511b and 521b cannot be made, and it can suppress that a sealing performance falls. Further, since the sub seal lip 82 has the uneven portion 82a at the tip end portion which is in sliding contact with the other surface 52b of the flange portion 52 in the metal ring 5, the sub seal lip 82, the main seal lip 81 and the metal ring 5 are provided. The space S surrounded by the cylindrical portion 51 is easy to ventilate the outside 3B of the housing 3. For this reason, even if the temperature in the space S changes during rotation of the crankshaft 10, it is difficult for the space S to become negative pressure. As a result, it is possible to prevent the lubricating oil to be sealed by the main seal lip 81 from being drawn between the main seal lip 81 and the sub seal lip 82, and further to suppress the deterioration of the sealing performance. .

  Further, the low friction surfaces 511 and 521 as described above are simply formed by blasting the metal ring 5, and the roughness can be easily set by selecting a medium, setting the ejection speed, or the like. be able to. Therefore, the process of reducing the frictional force on the crankshaft 10 is unnecessary, and the efficiency of the maintenance work of the crankshaft 10 can be improved. In addition, the oil seal 4 that can reduce the rotational torque of the crankshaft 10 can be manufactured appropriately. Moreover, since the metal ring 5 is detachable with respect to the crankshaft 10, the metal ring 5 set to an appropriate roughness can be selected and used according to the specifications and the like. When the roughness changes, maintenance work such as replacement of the metal ring 5 can be easily performed.

FIG. 2 shows a modification of the embodiment shown in FIG. In the oil seal 4 of this example, the elastic body 50 covering the metal ring 5 is not interposed between the cylindrical portion 51 of the metal ring 5 and the crankshaft 10, and the cylindrical portion 51 of the metal ring 5 is not connected to the crankshaft 10. The outer peripheral surface 10a is directly fitted. Instead, the protrusion 50c is formed in an annular shape at the inner diameter side end of the second covering portion 50b in the elastic body 50. In the fitting state of the metal ring 5 with respect to the crankshaft 10, the protrusion 50c is elastically deformed and is in elastic contact with the outer peripheral surface 10a of the crankshaft 10. A protrusion 50c indicated by a two-dot chain line in FIG. 2 indicates the original shape before elastic deformation. The fitting portion between the metal ring 5 and the crankshaft 10 is sealed by the elastic contact of the tongue-like protrusion 50c with the elastic deformation with respect to the crankshaft 10.
Since the other configuration is the same as the example shown in FIG. 1, the same reference numerals are given to the common parts, and the description of the configuration, operation and effect, etc. is omitted.

FIG. 3 shows another embodiment of the oil seal according to the present invention. In the oil seal 4 of the present embodiment, the core metal 7 constituting the seal body 6 is opposite in the direction of the axis L to the core metal 7 in the example of FIG. That is, the metal ring 5 and the seal body 6 are combined so that the flange 52 of the metal ring 5 and the inward flange 72 of the core 7 in the seal body 6 are both located on the outside 3B side. . Accordingly, the inward flange portion 72 of the cored bar 7 is formed to extend from the one end portion 71 d on the outer 3B side of the cylindrical portion 71 toward the inner diameter side. The main seal lip 81 and the sub seal lip 82 are arranged closer to the housing 3 than the sub seal lip 82, as in the above example. However, the sub seal lip 82 is a radial lip that elastically contacts the outer peripheral surface 51 c (low friction surface 511) of the cylindrical portion 51 in the metal ring 5. The sub-seal lip 82 has a shape whose tip end is reduced in diameter toward the outside 3B side, and dust from the outside 3B is prevented from reaching the main seal lip 81. The seal body 8 including the main seal lip 81 and the sub seal lip 82 covers the outer peripheral surface 71 of the cylindrical portion 51 of the core metal 7 and covers the one surface 72a of the inward flange portion 72 facing the outside 3B side. It is fixed. In this embodiment, the other surface 52b of the flange portion 52 in the metal ring 5 is not subjected to the blasting process for forming the low friction surface as in the above example. Also, a labyrinth r2 that suppresses the intrusion of dust from the outside 3B is formed at the closest portion in the axis L direction between the elastic body 50 covered with the metal ring 5 and the seal body 8 constituting the seal body 6. The In this case, since the path of the labyrinth r2 is longer than the labyrinth r1 in the above example, the labyrinth effect is further exhibited.
In addition, although the example of FIG. 3 shows that the same uneven part 82a as the above example does not exist in the front-end | tip part of the sub seal lip 82, you may provide such an uneven part as needed.
Since the other configuration is the same as the example shown in FIG. 1, the same reference numerals are given to the common parts, and the description of the configuration, operation and effect, etc. is omitted.

In the example of FIGS. 1 and 2, the uneven portion 82a is formed at the tip of the sub seal lip 82, but the uneven portion 82a may not be present. Further, in each of the embodiments, the thickness of the elastic body 50 is not particularly limited, but the thickness of the elastic body 50 may be larger than the thickness of the metal ring 50 in both the first covering portion 50a and the second covering portion 50b. It may be good or small.
Further, in each of the above embodiments, the low friction surface 521 with which the sub seal lip 82 is brought into relative sliding contact is formed to be a plateau structure surface. However, if the friction with the sub seal lip 82 can be reduced, It may not be a plateau structure surface. Further, the low friction surface 511 with which the main seal lip 81 is relatively slidably contacted may not be a plateau structure surface as long as low friction with the main seal lip 81 can be realized. Moreover, each low friction surface 511,521 is not restricted to what was formed in the roughness of 0.1-0.6 micrometer Ra, If it can implement | achieve lower friction than before, it will be 0.1-0.6 micrometer Ra. The roughness may be set outside the range, or the roughness may be defined by other parameters.
Furthermore, the secondary seal lip 82 may be omitted as necessary. The cross-sectional shape of the metal ring 5 is not limited to the L shape, and may be appropriately changed to another shape.
In addition, in the embodiment, an example in which the housing 3 is configured by the oil pan 1 and the cylinder block 2 in the automobile engine has been described. However, the present invention is not limited thereto, and for example, an automobile engine, a ship, or an agricultural machine. It may be a housing such as a geared motor or a pump used for the above. In this case, the movable shaft is the output shaft, and the mechanical motion mechanism unit is configured by the gear mechanism and the output shaft configured by meshing a plurality of gears. Further, the movable shaft is not limited to a shaft rotating, and may be a reciprocating motion along the axial direction. Furthermore, in the embodiment, the example in which the metal ring 5 is attached to the crankshaft 10 and the seal body 6 is attached to the housing 3 has been described. However, the metal ring 5 is attached to the housing 3 and the seal body 6 is connected to the crankshaft. 10 may be attached.

3 Housing 10 Crankshaft (movable shaft)
4 Oil seal 5 Metal ring 51 Cylindrical part (cylinder part)
51a One end 52 Flange 511, 521 Low friction surface 511b, 521b Valley 6 Seal body 81 Main seal lip (seal lip)
82 Secondary seal lip (seal lip)
82a Concavity and convexity L axis

Claims (8)

An oil seal provided between the movable shaft and a mechanical motion mechanism portion including a movable shaft and a housing that contains lubricating oil, and suppresses leakage of the lubricating oil contained in the housing;
A metal ring that is detachably attached to one of the housing and the movable shaft, and a seal body that is attached to the other of the housing and the movable shaft with a seal lip that is in sliding contact with the metal ring,
The oil seal according to claim 1, wherein the metal ring includes a low friction surface formed to have a roughness that reduces a frictional force caused by sliding contact of the seal lip. The oil seal according to claim 1,
The movable shaft is a rotating shaft;
The metal ring includes a cylindrical portion attached to one of the housing and the rotating shaft, and a flange portion extending in a radial direction from one axial end portion of the cylindrical portion,
The seal lip includes a main seal lip that is in sliding contact with the cylindrical portion, and a secondary seal lip that is in sliding contact with the flange portion,
The main seal lip is disposed on the housing side from the sub seal lip so as to suppress the leakage of lubricating oil in the housing, and the sub seal lip is disposed on the outer side from the main seal lip and is externally provided. It is shaped to prevent dust from reaching the main seal lip,
The oil seal according to claim 1, wherein a sliding contact surface with which the main seal lip is slidably contacted is the low friction surface formed to have a roughness for reducing the frictional force. The oil seal according to claim 2,
The oil seal according to claim 1, wherein a sliding contact surface of the flange portion in sliding contact with the sub seal lip is a low friction surface formed to have a roughness that reduces a frictional force caused by sliding contact with the sub seal lip. In the oil seal according to claim 2 or claim 3,
The sub-seal lip has an uneven part formed in a roughness range that allows ventilation at a tip part in sliding contact with the flange part. In the oil seal according to any one of claims 1 to 4,
The oil seal according to claim 1, wherein the low friction surface of the metal ring is a plateau structure surface having oil film retention. The oil seal according to claim 5,
The oil seal according to claim 1, wherein a width of the opening of the valley portion of the plateau structure surface is smaller than a sliding contact width of the seal lip with respect to the plateau structure surface. In the oil seal according to any one of claims 1 to 6,
The roughness for reducing the frictional force is set in a range of 0.1 to 0.6 μmRa. A method of manufacturing an oil seal that is provided between a mechanical motion mechanism including a movable shaft and a housing that contains lubricating oil and the movable shaft, and suppresses leakage of the lubricating oil contained in the housing,
The oil seal includes a metal ring that is detachably attached to one of the housing and the movable shaft, and a seal body that is attached to the other of the housing and the movable shaft with a seal lip that is in sliding contact with the metal ring. With
The slidable contact surface of the metal ring with which the seal lip is slidably contacted is subjected to blasting, and the slidable contact surface is set to a low friction surface set to a roughness that reduces frictional force due to the slidable contact with the seal lip. An oil seal manufacturing method characterized by the above.

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