JP5133082B2 - Constant velocity universal joint boot and its mounting structure - Google Patents

Description

  The present invention relates to a boot for a constant velocity universal joint and a mounting structure thereof, and more particularly to an improvement related technique of a boot fixing portion fixed to a shaft extended from an inner joint member of the constant velocity universal joint by a fastening band.

  As is well known, in a constant velocity universal joint incorporated in the power transmission mechanism of automobiles and various industrial machines, a bellows-shaped joint is used for the purpose of preventing foreign matter such as dust from entering the joint and preventing leakage of grease enclosed in the joint. A boot for a constant velocity universal joint (hereinafter also simply referred to as a boot) having a bent portion (expandable portion) or the like is attached.

  In this type of boot, the large-diameter end portion on one side of the bent portion is fitted and fixed to the outer peripheral surface of the outer joint member of the constant velocity universal joint, and the small-diameter end portion on the other side of the bent portion is constant-velocity. It is customary to be fitted and fixed to the outer peripheral surface of a shaft comprising a drive shaft, a driven shaft or an intermediate shaft extending from an inner joint member in the universal joint.

  Here, when attention is paid to the seal structure between the shaft and the small-diameter end portion of this type of boot, that is, the boot fixing portion for fitting and fixing the shaft to the outer peripheral surface of the shaft, the following configuration is known. It has become.

  That is, for example, in the following Patent Document 1, two circumferential protrusions are formed on the outer peripheral surface of the shaft, and between the concave groove existing between the protrusions and the inner peripheral surface of the boot fixing portion. A seal structure is disclosed in which a boot fixing portion is fixed to a shaft by being tightened by a tightening band from the outer peripheral side of the boot fixing portion with a seal member interposed.

  Further, for example, in Patent Document 2 below, a plurality of circumferential protrusions for defining a plurality of grooves are formed on the outer peripheral surface of the shaft, and a protrusion that fits into the groove in the axial center is booted. In addition to projecting on the inner peripheral surface of the fixed part, a seal member is interposed between the other concave groove of the shaft and the inner peripheral surface of the boot fixed part, and the tightening band is attached to the shaft from the outer peripheral side of the boot fixed part. A tightly fixed seal structure is disclosed.

JP 2007-239879 A Japanese Utility Model Publication No. 4-128536

  By the way, in order to form the seal structure as described above by incorporating the boot fixing portion existing at the small-diameter end of this type of boot into the shaft, a seal member (O-ring) is attached to the concave groove of the shaft. The boot fixing portion is moved in the axial direction through the shaft, and the boot fixing portion is positioned at a predetermined position covering the outer peripheral side of the seal member.

  When moving the boot fixing part in the axial direction at the time of this incorporation, the seal member mounted in the concave groove of the shaft is dragged by the boot fixing part to cause a deviation from the normal position in the axial direction. The sealing function may not be obtained. Further, when the seal member is dragged, the seal function may be impaired due to damage or damage to the seal member.

  This situation not only deteriorates the workability of the boot fixing part and shaft, but also reduces work efficiency, and also prevents foreign matters from entering the joint properly and prevents grease from leaking from the joint. It will be a big hindrance to sure prevention. Therefore, such a situation must be avoided as much as possible, but as a measure for that, in the past, attempts have been made to improve the O-ring, but according to this, the O-ring has a special specification. As a result, the cost increases, and it becomes difficult to mount the O-ring in the concave groove, so that the assembling property is deteriorated. Therefore, no actual measures have been found that can effectively deal with such a situation.

  In view of the above circumstances, the present invention causes the seal member to be dragged by the boot fixing portion when the boot fixing portion is incorporated into the shaft without causing the seal member to have a special specification, and the axial position is displaced or scratched. It is a technical problem to avoid such a situation and to secure a sufficient sealing function such as prevention of grease leakage and to improve the assembling property.

The boot according to the present invention, which has been created to solve the above technical problem, is fitted to the outer peripheral side of the shaft extended from the inner joint member of the constant velocity universal joint and is tightened from the outer peripheral side by a tightening band. in boot for the constant velocity universal joint having a boot fixing portion fixed to the shaft at one end, to the inner peripheral surface of the boot fixing portion to form a circumferential groove in which the ring-shaped seal member is attached, the boot fixing At the time of non-mounting to the shaft of the portion, the circumferential depth of the circumferential groove is set to be longer than the radial thickness of the seal member, and at the time of mounting the boot fixing portion to the shaft, The boot fixing portion is tightened from the outer peripheral side with a tightening band, so that the radial thickness of the boot fixing portion is reduced and the seal member is pressed against the outer peripheral surface of the shaft. And it is particularly characterized. Here, “when the boot fixing portion is not attached to the shaft” means that no external force is applied to the boot fixing portion and the seal member.

According to such a configuration, since the circumferential groove in which the seal member is mounted is formed on the inner peripheral surface of the boot fixing portion, the boot fixing portion is passed through the shaft in a state where the sealing member is mounted in the circumferential groove. If assembled, the axial position of the seal member does not deviate from the position where the circumferential groove is formed, and therefore the seal member is maintained in a state of being positioned at the normal axial position. In this case, since the radial depth of the circumferential groove is longer than the radial thickness of the seal member under a state in which no radial compressive force is applied to the boot fixing portion and the seal member, In a state where the seal member is mounted in the peripheral groove on the inner peripheral surface of the fixing portion, the seal member can be prevented from projecting to the inner peripheral side from the inner peripheral surface of the boot fixing portion. This avoids a situation in which the seal member is dragged in the axial direction when the boot fixing part is assembled to the shaft without causing the seal member to have a special specification, and the seal member is damaged. Therefore, it is possible to sufficiently exert a sealing function such as prevention of entry of foreign matter into the joint and prevention of grease leakage from the joint. In addition, by performing such assembling work, it is possible to improve assembling performance and work efficiency without incurring an increase in cost.

  Further, according to the above configuration, even if the seal member is an O-ring, it is not necessary to use a special specification, and it is possible to avoid an increase in cost, and it is easy to mount the O-ring when the boot fixing portion is incorporated into the shaft. Can be performed.

  Furthermore, according to the above configuration, the boot material is made of resin, so that a sufficient sealing function can be exerted, and the above-described useful effect can be obtained by adding a slight improvement to the existing boot. Can be obtained.

  On the other hand, the mounting structure of the constant velocity universal joint boot according to the present invention, which was created to solve the above technical problem, is provided with a seal member mounted on the circumferential groove of the above-described boot fixing portion, and from the inner joint member. By fitting a boot fixing portion on the outer peripheral side of the extended shaft and tightening the boot fixing portion from the outer peripheral side with a tightening band, the radial thickness of the boot fixing portion is reduced, and the sealing member Is pressed against the outer peripheral surface of the shaft.

  According to such a boot mounting structure, the boot fixing portion fitted to the outer peripheral side of the shaft is tightened from the outer peripheral side by the tightening band, and the radial thickness of the boot fixing portion is reduced, thereby providing a seal. Since the member is pressed against the outer peripheral surface of the shaft, an appropriate sealing function is ensured.

  In this case, it is preferable that the compression set amount of the seal member is set to be smaller than that of the boot material.

  In this way, even when the boot fixing part is in a state where the repulsive force decreases due to its compression set and it becomes difficult to obtain sufficient sealing performance, the sealing member secures sealing performance instead of the boot fixing part. Therefore, it becomes possible to maintain a sufficient sealing performance for a long time.

  In the boot mounting structure described above, boot mounting grooves are formed at two locations in the axial direction in the boot tightening region on the outer peripheral surface of the shaft, and the boot mounting grooves are raised from the grooves between the boot mounting grooves. It is preferable that a seal contact portion with which the seal member contacts is formed.

  If it does in this way, the inner peripheral surface of a boot fixing part will fit in the boot attachment groove formed in the both sides of the axial direction in the state where the seal member contacted the seal contact part in the outer peripheral surface of a shaft. Therefore, the axial positioning of the seal member is ensured.

  Furthermore, in the above-described boot mounting structure, when not tightened by the tightening band, the boot fixing portion in which the seal member is mounted in the circumferential groove is fitted to the outer peripheral side of the shaft, and the boot tightening area of the shaft is terminated as an inner side. It is preferable that the seal member is configured not to contact the outer peripheral surface of the shaft when moved in the axial direction toward the joint member side.

  In this way, as already described, when assembling the boot fixing portion to the shaft, not only the trouble of the seal member being dragged or scratched in the axial direction is avoided, but also the assemblability is extremely simple. It will be something.

Circumferential groove for mounting a seal member such as an O-ring on the inner peripheral surface of the boot fixing portion, which is an assembly portion of one end of the boot, when the boot is assembled to the shaft extended from the inner joint member of the constant velocity universal joint Therefore, if the boot fixing part is assembled through the shaft in a state where the seal member is mounted in the circumferential groove, the axial position of the seal member may be shifted from the position where the circumferential groove is formed. Disappear. Therefore, the seal member is maintained in a state where it is positioned at a normal axial position . In this case, since the radial depth of the circumferential groove is longer than the radial thickness of the seal member under a state in which no radial compressive force is applied to the boot fixing portion and the seal member, In a state where the seal member is mounted in the peripheral groove on the inner peripheral surface of the fixing portion, the seal member can be prevented from projecting to the inner peripheral side from the inner peripheral surface of the boot fixing portion. As a result , when the boot fixing portion is assembled to the shaft, a situation in which the seal member is dragged in the axial direction to cause a positional shift is avoided, and a situation in which the seal member is damaged or the like is less likely to occur. It is possible to sufficiently exert a sealing function such as prevention of foreign material intrusion and grease leakage from the inside of the joint. In addition, by performing such assembling work, it is not necessary to make the seal member a special specification, and an increase in cost can be avoided, and it is also possible to improve assembling performance and work efficiency. .

  Hereinafter, a boot for a constant velocity universal joint according to an embodiment of the present invention and a mounting structure thereof will be described with reference to the drawings.

  FIG. 1 is a vertical cross-sectional side view showing a main part of a mounting structure of a constant velocity universal joint boot 1, and is intended for a TJ (tripod type constant velocity universal joint) 2. The constant velocity universal joint 2 includes an outer member (outer joint member) 2a, in which three track grooves are formed in the axial direction on the inner peripheral surface and axial roller guide surfaces are provided on both sides of each track groove, A tripod member (inner joint member) 2b in which three leg shafts 2bb projecting in the radial direction on the outer peripheral surface are formed at equal intervals in the circumferential direction and each leg shaft 2bb are rotatably mounted and inserted into the track groove. And a roller 2c for transmitting torque between the outer joint member 2a and the inner joint member 2b. The shaft 3 such as a drive shaft, driven shaft or intermediate shaft is extended from the inner joint member 2b. Specifically, the shaft end of the shaft 3 is splined into the shaft hole of the inner joint member 2b. It is in the state fitted by.

  In the boot 1 attached to the constant velocity universal joint 2, the large-diameter end 1b formed on one side of the bellows-like bent portion 1a is fitted and fixed to the outer peripheral surface of the axial end portion of the outer joint member 2a. At the same time, the small-diameter end 1c formed on the other side of the bent portion 1a is fitted and fixed to the outer peripheral surface in the axial direction intermediate portion of the shaft 3 extending from the inner joint member 2b.

  Referring to FIG. 2, a detailed description will be given of the small diameter end 1c of the boot 1, that is, the boot fixing portion 1c for fitting and fixing the boot 1 to the shaft 3. The inner peripheral surface 1ca of the boot fixing portion 1c includes: A circumferential groove 1cb having a rectangular cross section in which a seal member 4 made of an O-ring is mounted is formed. And, in the state shown in the figure, that is, in the state where the fastening force does not act on the boot fixing portion 1c and the seal member 4, the depth (diameter depth) D of the circumferential groove 1cb is the thickness of the seal member 4 ( (Thickness in radial direction) is set longer than d. Therefore, under the state where the seal member 4 is mounted in the circumferential groove 1cb of the boot fixing portion 1c, the inner peripheral surface of the seal member 4 does not protrude from the inner peripheral surface 1ca of the boot fixing portion 1c. A band contact recess 1cc is formed on the outer peripheral surface side of the peripheral groove 1cb forming portion of the boot fixing portion 1c, with the peripheral groove 1cb forming portion being the central portion in the axial direction.

  FIG. 3 shows a band that is fastened to a band contact recess 1cc formed on the outer peripheral surface of the boot fixing portion 1c in a state where the boot fixing portion 1c is fitted to a fitted portion (boot tightening region) 3a of the shaft 3. 5 shows a state in which 5 is fitted and tightened and fixed. In this case, two annular ridges 3b are formed in the fitted portion 3a of the shaft 3 so as to be separated from each other by a predetermined dimension in the axial direction, and each annular ridge is provided between the annular ridges 3b. A boot mounting groove 3c adjacent to 3b is formed. Further, a seal contact portion 3d that forms a flat cylindrical surface that protrudes from each boot attachment groove 3c and contacts the seal member 4 is formed between the boot attachment grooves 3c. It should be noted that both ends of the band contact recess 1cc on the outer peripheral surface of the boot fixing portion 1c and the fastening band 5 in the axial direction protrude from the two annular ridges 3b of the shaft 3 toward both sides in the axial direction.

  Under this condition, the boot fixing portion 1c is tightened from the outer peripheral side with the tightening band 5, so that the radial thickness of the boot fixing portion 1c is reduced, whereby the seal member 4 is pressed against the outer peripheral surface of the shaft 3. , Sealability is ensured. Therefore, the cross-sectional shape of the seal member 4 exhibits a circular shape when the tightening force is not shown in FIG. 2, but has a long elliptical shape in the axial direction when the tightening force is shown in FIG. The compression set amount of the seal member 4 is set to be smaller than the compression set amount of the boot material.

  Further, under the action of the tightening force shown in FIG. 3, boot attachments formed at two locations in the axial direction of the fitted portion 3 a of the shaft 3, specifically, at two locations on both sides in the axial direction of the seal contact portion 3 d with which the seal member 4 contacts. The groove 3c is in a state in which the meat portion on the inner peripheral surface side of the boot fixing portion 1c is fitted or in a state of being bitten. Therefore, the seal member 4 is not only properly positioned in the axial direction, but also has a very high sealing performance around the seal member 4.

  On the other hand, when the boot 1 is assembled to the shaft 3 and the constant velocity universal joint 2, in order to position the boot fixing portion 1c on the fitted portion 3a of the shaft 3, as shown in FIG. In a state where the seal member 4 is mounted in the groove 1cb, the boot fixing portion 1c is passed through the shaft 3 from the right end portion and moved in the axial direction. In that case, since the axial relative movement of the seal member 4 with the boot fixing portion 1c is restricted by the circumferential groove 1cb, the seal member 4 is in a period until the boot fixing portion 1c moves to the fitted portion 3a of the shaft 3. The seal member 4 is not dragged and the position does not shift. In addition, since the seal member 4 is mounted in the circumferential groove 1cb of the boot fixing portion 1c without protruding inwardly, the boot fixing portion 1c is moved in the axial direction around the fitted portion 3a of the shaft 3. Even in this case, the contact between the seal member 4 and the boot mounting groove 3c is avoided, and the seal member 4 reaches a position where it can contact the seal contact portion 3d of the shaft 3 accurately.

  Thereafter, the tightening band 5 is fitted into the band contact recess 1cc on the outer peripheral surface of the boot fixing portion 1c and tightened, whereby the already described state shown in FIG. 3 is obtained. After that, the inner joint member 2b, the outer joint member 2a, and the like are incorporated into the right end portion of the shaft 3 and grease is sealed, and the large-diameter end portion 1b of the boot 1 is fitted to the outer peripheral surface of the outer joint member 2a. By fixing with the fastening band 6, the mounting structure of the boot 1 as shown in FIG. 1 is obtained.

  In the above embodiment, the present invention is applied to TJ (tripod type constant velocity universal joint), but besides this, BJ (ball fixed joint), DOJ (double offset type joint), LJ (cross groove type). The present invention can be similarly applied to a joint), UJ (undercut free joint), and the like.

It is a schematic longitudinal cross-sectional side view which shows the attachment structure of the boot for constant velocity universal joints concerning embodiment of this invention. It is a principal part expansion vertical side view which shows the boot for constant velocity universal joints concerning embodiment of this invention as a single unit. It is an expanded vertical side view which shows the principal part of the attachment structure of the boot for constant velocity universal joints concerning embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Constant velocity universal joint boot 1c Boot fixing | fixed part 1ca Inner peripheral surface 1cb of a boot fixing | fixed part 2 Circumferential groove 2 Constant velocity universal joint 2b Inner joint member 3 Shaft 3a Shaft fitting part (boot tightening area | region)
3c Boot mounting groove 3d Seal contact part 4 of shaft Seal member (O-ring)
5 Tightening band D Radial depth of circumferential groove d Radial thickness of seal member

Claims (6)

For constant velocity universal joints having a boot fixing portion at one end that is fitted to the outer peripheral side of the shaft extended from the inner joint member of the constant velocity universal joint and is tightened from the outer peripheral side by a fastening band and fixed to the shaft. In boots,
A circumferential groove to which a ring-shaped seal member is attached is formed on an inner peripheral surface of the boot fixing portion, and a radial depth of the circumferential groove is determined when the boot fixing portion is not attached to the shaft. The radial direction of the boot fixing part is set to be longer than the radial thickness of the boot fixing part, and when the boot fixing part is mounted on the shaft, the boot fixing part is tightened from the outer peripheral side with a tightening band. A constant velocity universal joint boot, characterized in that the thickness is reduced and the seal member is pressed against the outer peripheral surface of the shaft . The constant velocity universal joint boot according to claim 1, wherein the seal member is an O-ring. The boot for a constant velocity universal joint according to claim 1 or 2, wherein the boot material is a resin. A seal member is attached to the circumferential groove of the constant velocity universal joint boot according to any one of claims 1 to 3 , and a boot fixing portion is fitted to the outer peripheral side of the shaft extended from the inner joint member, and The boot fixing portion is tightened from the outer peripheral side with a tightening band to reduce the thickness of the boot fixing portion in the radial direction, and the seal member is pressed against the outer peripheral surface of the shaft. Mounting structure for joint boots. In the boot tightening region on the outer peripheral surface of the shaft, a boot mounting groove is formed at two locations in the axial direction, and the seal is raised between the boot mounting grooves and contacts the seal member between the boot mounting grooves. The structure for mounting a constant velocity universal joint boot according to claim 4, wherein a contact portion is formed. When not tightened by the tightening band, the boot fixing portion in which the seal member is mounted in the circumferential groove is fitted to the outer peripheral side of the shaft, and the shaft toward the inner joint member side is terminated with the boot tightening region of the shaft as an end. The structure for mounting a boot for a constant velocity universal joint according to claim 4 or 5 , wherein the seal member is configured not to contact the outer peripheral surface of the shaft when moved in the direction.

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