JP2013108560A - Sealing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing structure which can prevent effectively an oil leakage without removing a helical continuous groove after machining hardened steel, or processing by a forming tool such that no helical continuous groove is formed.SOLUTION: A sealing structure includes: an oil seal having a plurality of lip parts; an oil sealing surface to which the lip part of the oil seal contacts, wherein the oil sealing surface is finished by machining hardened steel. At least between the lip parts at the oil sealing surface, a helical non-continuous groove is formed by machining the hardened steel.

Description

  The present invention relates to a seal structure, and more particularly to a seal structure including an oil seal having a plurality of lip portions and an oil seal surface with which the lip portions of the oil seal come into contact.

  Constant velocity universal joints are joints that can transmit torque smoothly and smoothly even if the angle between the input shaft and the output shaft varies. They are widely used in automobile drive shafts, propeller shafts, and industrial machinery. Especially in automobiles, it is an indispensable functional component for front wheel drive shafts of FF vehicles, front wheels and rear wheel drive shafts of 4WD vehicles, and is now used in most passenger cars. Generally, the drive shaft uses a fixed type constant velocity universal joint that has a large angle on the wheel side but does not have a sliding function, and a sliding type constant velocity universal joint that can slide on the differential side. The speed universal joint is connected by an intermediate shaft.

  In an outer joint member or the like of a sliding type constant velocity universal joint, a contact surface with an oil seal (a portion that blocks outflow of differential oil) is conventionally finished by grinding or the like. However, in recent years, hardened steel cutting has been applied in place of grinding that requires environmentally undesirable coolant due to environmental considerations and the like. Hardened steel cutting is simply cutting, and since cutting is usually performed in the state of raw material, it was referred to as hardened steel cutting in order to clarify that the cutting was after heat treatment (after quenching). Since cutting is performed after quenching, the heat treatment deformation of the material can be removed in this cutting process.

  However, in the case of hardened steel cutting, since only cutting is performed, a spiral groove 81 is formed on the cutting surface 80 as shown in FIG. If such a spiral groove 81 is formed, oil may flow out along the groove 81.

  Therefore, the lead formed in this way (helical continuous groove) is removed with an elastic grindstone (dry grindstone) (Patent Document 1), and the lead is not generated using a general-purpose tool (patent) Document 2) has been proposed.

JP 2007-15091 A JP 2011-12752 A

  However, if an elastic grindstone is used as described in Patent Document 1, this elastic grindstone is required in addition to the cutting tool, and the shape of the grindstone is liable to break down, and this grindstone needs to be dressed regularly. It was. For this reason, there are problems such as an increase in cost and an increase in cycle time.

  As shown in Patent Document 2, when the total tool is used, if the total tool has a long cutting length, the cutting resistance increases, which has a bad influence on the tool and the machine. It is not suitable for processing the oil seal surface of long constant velocity universal joints. In addition, in order for the oil seal surface to maintain a sealing property, not only a lead (a spiral continuous groove) does not occur, but also a straight surface shape must be maintained. However, as the total number of cutting operations increases, the straight surface shape gradually collapses. In particular, the longer the cutting length, the more prominent. Therefore, also from this point, in the case of a constant velocity universal joint, it turns out that the process by a total type tool is inadequate.

  Therefore, in view of such circumstances, the present invention is a seal structure that can effectively prevent oil leakage without removing the lead after cutting hardened steel or processing so as not to generate a lead with a complete tool. Is to provide.

  The seal structure of the present invention comprises an oil seal having a plurality of lip portions, and an oil seal surface that comes into contact with the lip portions of the oil seal, and the oil seal surface is finished by quenching steel cutting. A groove that is not spirally formed is formed by quenching steel cutting at least between the lip portions on the oil seal surface.

  According to the seal structure of the present invention, since there is a groove that is not spirally connected between the lip portions on the oil seal surface, oil can be prevented from flowing out to the outside.

  The grooves that are not spirally connected are constituted by a large number of independent circumferential grooves. Such grooves can effectively prevent the oil from flowing out.

  The oil seal surface may be a cylindrical surface centered on the axis of the rotating shaft, a conical surface centered on the axis of the rotating shaft, or a vertical surface orthogonal to the axis of the rotating shaft. Good.

  In the fixed type constant velocity universal joint of the present invention, the seal surface formed on the stem of the outer joint member is the oil seal surface of the seal structure.

  In the sliding type constant velocity universal joint of the present invention, the seal surface formed on the stem of the outer joint member is the oil seal surface of the seal structure.

  The bearing structure of the present invention is a bearing structure having a seal portion, and the seal portion is constituted by the seal structure.

  In the present invention, since oil can be prevented from flowing out, a highly accurate sealing function can be exhibited. Moreover, since it is not necessary to use a conventional elastic grindstone after quench cutting, the cost can be reduced, and the working time can be shortened by replacing the grindstone and moving the work place. In addition, it does not require regular dressing and is greatly improved in production. Moreover, since the cutting tool to be used does not need to be an all-type tool, it is optimal for processing the oil seal surface of a constant velocity universal joint having a long cutting length.

  Since the oil seal surface is constituted by a large number of independent circumferential grooves, it is possible to effectively prevent oil from flowing out to the outside, and it is excellent in workability and contributes to cost reduction.

  The oil seal surface may be a cylindrical surface centered on the axis of the rotating shaft, a conical surface centered on the axis of the rotating shaft, or a vertical surface orthogonal to the axis of the rotating shaft. Well, this seal structure has a wide range of applications and is highly versatile.

  It is optimal for various seal structures such as fixed constant velocity universal joints, sliding constant velocity universal joints, and bearing structures.

It is sectional drawing which shows the seal structure of this invention. It is a principal part enlarged view of the constant velocity universal joint using the said seal structure. FIG. 3 is a simplified diagram showing a front wheel drive shaft using the constant velocity universal joint shown in FIG. 2. It is process drawing which shows the oil seal surface processing operation | movement of the seal structure of the said FIG. FIG. 2 is a simplified view of a groove formed by the operation of the tool shown in FIG. 1. It is a simplified diagram showing a rotating shaft in a state of being sealed with an oil seal. It is a simplified diagram showing another rotating shaft in a state of being sealed with an oil seal. It is a schematic diagram which shows another rotating shaft of the state sealed with the oil seal. It is principal part sectional drawing which shows the bearing structure using the seal structure of this invention. It is a simplified diagram showing a spiral groove formed by conventional quench cutting.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a sectional view showing a seal structure according to the present invention, and FIG. 2 is an enlarged side view of a constant velocity universal joint (sliding constant velocity universal joint) using the seal structure.

  The sliding type constant velocity universal joint 3 is used for a front wheel drive shaft as shown in FIG. 3, for example. Such a drive shaft includes a shaft 1, a fixed type constant velocity universal joint 2 connected to one end of the shaft 1, and a sliding type constant velocity universal connected to the other end of the shaft 1. The fixed type constant velocity universal joint 2 is connected to the wheel 4 side (wheel side), and the sliding type constant velocity universal joint 3 is connected to the differential (difference) 5 side.

  The sliding type constant velocity universal joint 3 includes an outer joint member 6, an inner joint member (not shown), a torque transmission member interposed between the inner joint member and the outer joint member, and the like. Further, as shown in FIG. 2 and the like, the outer joint member 6 includes a mouth portion 6a in which the inner joint member and the torque transmission member are accommodated, and a stem portion 6b that is connected to the bottom wall 7 of the mouth portion 6a. Become. In addition, the opening part of the mouse | mouth part 6a of the outer joint member 6 is sealed with the boot 8, as shown in FIG. As this sliding type constant velocity universal joint, even if it is a double offset type constant velocity universal joint using a ball as a torque transmission member or a cross groove type constant velocity universal joint, the inner joint member is a tripod member. A tripod type constant velocity universal joint may be used.

  The fixed type constant velocity universal joint 2 includes an outer joint member 10, an inner joint member (not shown), a torque transmission member interposed between the inner joint member and the outer joint member, and the like. The outer joint member 10 includes a mouth portion 10a in which the inner joint member and the torque transmission member are accommodated, and a stem portion 10b that is provided continuously with the bottom wall 11 of the mouth portion 10a. Note that the opening of the mouth portion 10 a of the outer joint member 6 is sealed with a boot 12. The fixed type constant velocity universal joint may be a Rzeppa type constant velocity universal joint in which the track groove is an arc or an undercut free type constant velocity universal joint in which the track groove is an arc and a straight portion.

  Incidentally, as shown in FIG. 2, a boss portion 15 is formed on the mouth portion side of the stem portion 6b of the outer joint member 6 of the sliding type constant velocity universal joint 3, and an outer diameter surface 16 of the boss portion 15 is formed. The oil seal surface M is a cylindrical surface. That is, the seal structure of the present invention includes an oil seal 20 having at least two lip portions 22a and 22b, and the oil seal surface M with which the lip portions 22a and 22b come into contact (pressure contact).

  Here, as shown in FIGS. 1 and 2, the oil seal 20 includes a seal body 22 made of a rubber elastic material having a metal ring 21 embedded therein. The seal body 22 has a seal lip portion 22a and a dust lip portion 22b. The seal lip portion 22a is pressed toward the oil seal surface M by a spring member 23, and the wedge-shaped lip tip portion 24 is oil seal. Pressed against the surface M. Thereby, the oil can be sealed. The dust lip 22b is provided as an auxiliary, and is in close contact with the oil seal surface M to prevent intrusion of dust and the like.

  The outer joint member 6 of the constant velocity universal joint 3 is made of, for example, medium carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C. A hardened layer is formed on the outer diameter surface 16. As a hardening process which forms a hardened layer, induction hardening, carburizing hardening, etc. are performed. Quenching by high-frequency heating is a quenching method that applies the principle of heating a conductive object by placing Joule heat in a coil through which high-frequency current flows, and generating Joule heat by electromagnetic induction. is there. Carburizing and quenching is a process in which carbon is impregnated from the surface layer (carburizing treatment) by heating the steel in a carburizing agent such as activated carbon-rich gas, liquid or solid for a long time. It is a method of quenching and tempering steel.

  Then, the outer diameter surface 16 of the boss portion 15 constituting the oil seal surface M is subjected to hardened steel cutting with a cutting tool 26 having a cutting tool 25 as shown in FIG. Hardened steel cutting is simply cutting, and since cutting is usually performed in the state of raw material, it was referred to as hardened steel cutting in order to clarify that the cutting was after heat treatment (after quenching). Since cutting is performed after quenching, the heat treatment deformation of the material can be removed in this cutting process.

  The tool 25 of the cutting tool 26 is a tool capable of cutting hardened steel. For example, a sintered tool obtained by adding a special ceramic binder to CBN (cubic boron nitride) can be used.

  The cutting tool 26 and the outer joint member 6 that is a workpiece are moved relative to each other in the axial direction and the radial direction, and the outer diameter surface of the boss portion 15 that is the machining surface of the workpiece by the cutting tool 26. 16 will be cut.

  Specifically, the tool 25 of the cutting tool 26 performs an operation as shown in FIG. 4 on the outer joint member 6. In this case, the outer joint member 6 that is a workpiece is supported by a support device (not shown) that can rotate around its axis. The cutting tool 25 is supported by a drive mechanism capable of reciprocating along the axial direction of the outer joint member 6 and reciprocating along a direction orthogonal to the axial direction.

  In such a set state, the outer joint member 6 that is a workpiece is rotated around its axis, and the cutting tool 25 is separated from the outer diameter surface 16 of the boss portion 15 by a predetermined amount in the outer diameter direction. First, the outer joint member 6 is moved in the arrow A1 direction along the axial direction of the outer joint member 6 to the axial cutting start position. At that position, the cutting tool 25 is moved by a predetermined amount along the direction of the arrow B1 perpendicular to the axial direction of the outer joint member 6. As a result, the outer joint member 6 that is a workpiece is cut in a direction perpendicular to the outer diameter surface 16 of the boss portion 15. Thereafter, the cutting tool 25 is moved in the direction of the arrow C1 which is the direction opposite to the arrow B1 direction, thereby separating (retracting) the cutting tool 25 in the vertical direction with respect to the outer diameter surface 16 of the boss portion 15. Thereby, the circumferential groove 30 (30A) as shown in FIG. 5 can be formed.

  Thereafter, the outer joint member 6 is moved by a predetermined amount in the arrow A2 direction along the axial direction. At that position, the cutting tool 25 is moved by a predetermined amount along the direction of the arrow B2 orthogonal to the axial direction of the outer joint member 6, and then the cutting tool 25 is moved in the direction of the arrow C2 opposite to the direction of the arrow B2. Thereby, the circumferential groove 30 (30B) as shown in FIG. 5 can be formed. Thereafter, similarly, by moving with arrows A3, B3, C3..., A plurality of circumferential grooves 30 are formed along the axial direction in a predetermined range in the axial direction, and the oil seal surface M can be formed.

  The moving direction, moving amount, transfer speed, rotational speed of the outer joint member 6 and the like of the cutting tool 25 are controlled by control means, storage means, etc. (not shown). The control means can be composed of, for example, a microcomputer in which a ROM (Read Only Memory), a RAM (Random Access Memory), and the like are connected to each other via a bus with a central processing unit (CPU) as a center. The storage means (storage device) can be composed of an HDD (Hard Disc Drive), a DVD (Digital Versatile Disk) drive, a CD-R (Compact Disc-Recordable) drive, an EEPROM (Electronically Erasable and Programmable Read Only Memory), or the like. The ROM can store programs and data executed by the CPU.

  The range in which the plurality of independent circumferential grooves 30 are formed only needs to be formed at least between the range in which the seal lip portion 22a is in sliding contact and the range in which the dust lip portion 22b is in sliding contact. For this reason, even if the circumferential groove 30 is formed over the entire range from the range where the seal lip portion 22a is slidably contacted to the range where the dust lip portion 22b is slidably contacted as the oil seal surface M, the seal lip portion 22a is slidably contacted. It may be formed only between the range and the range where the dust lip 22b is in sliding contact. Further, the circumferential groove 30 may be formed in the entire range of the oil seal surface M.

  According to the seal structure of the present invention, the processed surface of the workpiece (the outer diameter surface 16 of the boss portion 15 of the outer joint member 6) can be cut into an oil seal surface M without a continuous spiral groove. For this reason, if it is such an oil seal surface M, it can prevent that oil flows out outside and can exhibit a highly accurate seal function. Moreover, since it is not necessary to use a conventional elastic grindstone, it is possible to reduce the cost, and it is possible to shorten the work time by replacing the grindstone and moving the work place, etc. It does not require regular dressing and will be significantly better in production. Moreover, since the cutting tool to be used does not need to be an all-type tool, it is optimal for processing the oil seal surface of a constant velocity universal joint having a long cutting length.

  By the way, as the formation site of the oil seal surface M, in the above-described embodiment, as shown in FIG. 6, it is the cylindrical surface 52 centered on the axis of the rotation shaft 50 (50a), but as shown in FIG. The conical surface 53 may be centered on the axis of the rotation shaft 50 (50b). Furthermore, as shown in FIG. 8, it may be a vertical plane 54 orthogonal to the axis of the rotation axis (50b). Note that the oil seal 20 shown in FIG. 8 has a lip portion 22 c that contacts the vertical surface 54. 6 to 8 is a stationary member 51 into which the oil seal 20 is fitted.

  Incidentally, the oil seal surface M is also formed in the outer joint member 10 of the fixed type constant velocity universal joint. For this reason, the oil seal surface M is processed by the oil seal surface processing method.

  Therefore, the oil seal surface M can also be cut to an oil seal surface without a spiral groove, and oil can be prevented from flowing out.

  Next, FIG. 9 shows a bearing structure. This bearing structure pivotally supports a rotating shaft 56 inserted into the fixing member 55 and includes a bearing 57 and a seal portion 58.

  The bearing 57 includes an inner ring 61, an outer ring 62, and a ball 63 as a rolling element interposed between the inner ring 61 and the outer ring 62. Further, the seal part 58 includes an oil seal 20, the oil seal 20 shown in FIG. 1 and the like, and an oil seal surface M with which the lip parts 22a and 22b of the oil seal 20 come into contact.

  Therefore, in the bearing structure as shown in FIG. 9, the oil seal surface M of the rotating shaft 56 is processed by the processing method shown in FIG. For this reason, the oil seal surface M without a spiral groove can be formed, and oil can be prevented from flowing out. For this reason, the bearing structure which exhibits a highly accurate sealing effect can be provided.

  By the way, the oil seal is used for an automobile engine, a geared motor, and the like, and mainly prevents oil leakage from the end of the rotating shaft and intrusion of dust from the outside. For this reason, it is used as a sealing device for machines in various fields such as automobiles, airplanes, ships, railway vehicles, construction machinery, agricultural machinery, petrochemical plants, and home appliances. Therefore, the seal structure of the present invention can be used, and by using such a seal structure, various industrial machines that exhibit a highly accurate sealing effect can be provided.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above-described embodiment, as an oil seal, FIGS. It is not limited to those shown in FIG. 1, and various types of lip portions having at least two lip portions can be used.

  Further, the size, shape, material, etc. of the cutting tool 25 can be variously changed according to the material, hardness, etc. of the processed surface of the workpiece. The depth and formation range of the circumferential groove to be cut can be variously changed within a range that does not leak oil. In the above embodiment, the cutting tool 25 side is moved in the axial direction and the radial direction. However, the workpiece side may be moved in the axial direction and the radial direction, or both may be moved.

2 Fixed constant velocity universal joint 3 Sliding constant velocity universal joint 6b Stem portion 6a Mouse portion 6 Outer joint member 10b Stem portion 10 Outer joint member 20 Oil seal 22a, 22b Lip portion 22c Lip portion 30 Circumferential groove 50 Rotating shaft 52 Cylindrical surface 53 Conical surface 54 Vertical surface M Oil seal surface

Claims (8)

An oil seal having a plurality of lip portions, and an oil seal surface that comes into contact with the lip portions of the oil seal, wherein the oil seal surface is finished by quenching steel cutting,
The seal structure according to claim 1, wherein a groove that is not spirally formed is formed by quenching steel cutting at least between the lip portions on the oil seal surface.   2. The seal structure according to claim 1, wherein the grooves not connected in a spiral shape are constituted by a plurality of independent circumferential grooves.   The seal structure according to claim 1, wherein the oil seal surface is a cylindrical surface centering on an axis of a rotation shaft.   3. The seal structure according to claim 1, wherein the oil seal surface is a conical surface centered on an axis of a rotation shaft.   The seal structure according to claim 1, wherein the oil seal surface is a vertical surface orthogonal to the axis of the rotation shaft.   It is a fixed type constant velocity universal joint, Comprising: The seal surface formed in the stem of an outer joint member is an oil seal surface of the seal structure of any one of the said Claims 1-5. Fixed constant velocity universal joint.   It is a sliding type constant velocity universal joint, Comprising: The seal surface formed in the stem of an outer joint member is an oil seal surface of the seal structure of any one of the said Claims 1-5. Sliding constant velocity universal joint.   A bearing structure having a seal portion, wherein the seal portion is configured by the seal structure according to any one of claims 1 to 5.

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