WO2010064690A1

WO2010064690A1 - Seal structure

Info

Publication number: WO2010064690A1
Application number: PCT/JP2009/070345
Authority: WO
Inventors: 一彦末岡; 健天沼
Original assignee: 株式会社フコク
Priority date: 2008-12-04
Filing date: 2009-12-03
Publication date: 2010-06-10
Also published as: JP5577032B2; JP2010133487A

Abstract

A seal structure is configured so as to provide, easily and at low cost, good sealing properties between a resin boot and a shaft or an outer case of a constant velocity joint even in an environment in which high temperature and low temperature are repeated, and the sealing properties can be maintained for a long time period. A seal structure which is formed between a small-diameter-side end section (P1) of a boot (4) and a shaft (2a) of a constant velocity joint (2) with the small-diameter-side end section fastened to the shaft by a fastening member (6). A ridge seal (10) which is continuous along the inner peripheral surface (Ps) of the region fastened by the fastening member and projects in the center direction is provided to the small-diameter-side end section, and a containing space (12) in which, with the small-diameter-end section fastened to the shaft, the ridge seal elastically deformed and curved is contained is provided to either the inner peripheral surface of the small-diameter-side end section and/or the outer peripheral surface of the shaft. The ridge seal is, while being kept in contact with the shaft under pressure, permitted to be elastically deformed in the containing space by thermal expansion and thermal contraction.

Description

Seal structure

The present invention relates to a seal structure, and more particularly to a seal structure for improving the sealing performance between a resin boot for a constant velocity joint and the shaft or outer case of the constant velocity joint.

Conventionally, for example, constant velocity joints used for driving shafts (propeller shafts) and propulsion shafts (propeller shafts) of automobiles are sealed with grease as a lubricant and prevented from entering dust and water from the outside. Those equipped with the above-mentioned resin boots have been put into practical use, and various seal structures for maintaining the sealing performance have been studied. As an example, Patent Document 1 discloses a resin boot having a small-diameter cylindrical portion that is fastened to a shaft of a constant velocity joint. The small-diameter cylindrical portion of the resin boot is provided with a resin seal portion in an inner peripheral region to be tightened by a fastening member such as a fastening band, and a resin lip is provided around the inner peripheral surface of the seal portion. Protruding continuously along the direction.

When such a small-diameter cylindrical portion is tightened with a fastening member, the sealing portion is crushed and pressed against the shaft by the tightening force at that time, and the tip of the lip is pressed against the lip groove formed on the shaft to be pressed. Thereby, the sealing performance between the boot and the shaft is maintained.
JP 2004-291438 A

By the way, in the seal structure in which the projecting seal such as the lip and the projection as described above is crushed by the tightening force of the fastening member and its tip is pressed against the shaft, the projecting seal is crushed from the tip side toward the root side. In this state, the shaft is pressed against the shaft, so that the whole is compressed and deformed, and is pressed against the shaft without any gap. When the boot fastened to the shaft in this state is an inboard side boot, in particular, an atmosphere in which high temperature (atmospheric temperature when the engine is driven) and low temperature (atmospheric temperature when the engine is stopped) is repeated. Used in.

Here, when the boot and the shaft as described above are used in a high-temperature atmosphere, a phenomenon (so-called “sagging”) in which the elastic restoring force of the projecting seal that is compressively deformed by the fastening force of the fastening member may occur. is there.
Specifically, in a high temperature atmosphere, the entire boot including the fastening member is thermally expanded. However, since the protruding seal is made of resin, the amount of expansion is larger than that of the metal fastening member. . At this time, since the projecting seal is in a state of being pressed against the shaft without a gap with a constant tightening force by the fastening member, thermal expansion in a high temperature atmosphere is forcibly limited. As a result, a phenomenon in which the elastic restoring force of the projecting seal that is compressively deformed by the fastening force of the fastening member is reduced (so-called sag) occurs.

As described above, when “stickiness” occurs in the projecting seal, the surface pressure (pressure contact force) of the projecting seal with respect to the shaft decreases. Furthermore, when the ambient temperature decreases from a high temperature (when the engine is driven) to a low temperature (when the engine is stopped), the projecting seal also contracts due to this temperature decrease. Since the projecting seal contracts in a state where the surface pressure (pressure contact force) of the projecting seal is reduced, the surface pressure (pressure contact force) of the projecting seal against the shaft further decreases, or the tip of the projecting seal and the shaft There may be a gap between the two. As a result, depending on the degree of decrease in the pressure contact force and the size of the gap, it becomes difficult to maintain the sealability between the boot and the shaft over a long period of time, resulting in early grease leakage. May occur or dust or water may enter from the outside.

In the boot of Patent Document 1 described above, a heat load process is performed in advance on the seal portion of the small-diameter cylindrical portion to cause initial “sagging”. In the heating load process, the small-diameter cylindrical portion is reduced in diameter by a heated pressing jig.
However, in this process, a press jig must be separately prepared in addition to the boot manufacturing apparatus, and a heating load processing process is separately required in addition to the boot manufacturing process. Time is required, and the manufacturing cost of the boot increases accordingly.
Further, in the boot described in Patent Document 1, no study has been made on a decrease in sealing performance when the ambient temperature is decreased from a high temperature (when the engine is driven) to a low temperature (when the engine is stopped).
On the other hand, there has also been proposed a method in which a minute protrusion is formed on the tip side of a projecting seal that is in pressure contact with the shaft, and, in a high temperature atmosphere, the minute protrusion is crushed to prevent deterioration of the sealing property due to “sagging” However, even in this proposal, no consideration has been given to a decrease in sealing performance when the ambient temperature decreases from a high temperature (when the engine is driven) to a low temperature (when the engine is stopped).

Therefore, the object of the present invention is to provide a simple seal between the constant velocity joint resin boot and the constant velocity joint shaft or outer case, even in an atmosphere where high and low temperatures are repeated, and An object of the present invention is to provide a sealing structure that can be improved at low cost and can maintain its sealing performance over a long period of time.

In order to achieve such an object, the present invention provides the small diameter side end portion and the shaft in a state where the small diameter side end portion of the resin boot for constant velocity joint is fastened to the shaft of the constant velocity joint by a fastening member. The small-diameter side end is continuous in the circumferential direction along the inner peripheral surface of the region to be tightened by the fastening member, and from the inner peripheral surface to the central direction. A protruding projecting seal is provided, and at least one of the inner peripheral surface of the small diameter side end portion and the outer peripheral surface of the shaft is in a state where the small diameter side end portion is fastened to the shaft by the fastening member. An accommodation space is provided in which the projecting seal is accommodated by being elastically deformed, and the projecting seal is in thermal contact with the shaft while maintaining a state in pressure contact with the shaft. Elastic deformation due is permitted.
In addition, the present invention provides a constant-velocity joint resin boot between the large-diameter side end and the outer case in a state where the large-diameter end is fastened to the outer case of the constant-velocity joint by a fastening member. In the sealing structure that is configured, the large-diameter side end is continuous in the circumferential direction along the inner peripheral surface of the region to be tightened by the fastening member, and protrudes in the central direction from the inner peripheral surface A state-like seal is provided, and the large-diameter side end is fastened to the outer case by the fastening member on at least one of the inner peripheral surface of the large-diameter end and the outer peripheral surface of the outer case. In this case, an accommodation space is provided in which the projecting seal is accommodated by being elastically deformed, and the projecting seal is thermally expanded in the accommodation space while maintaining a state of being pressed against the outer case. Elastic deformation due to shrinkage is permitted.
In the present invention, the storage space is formed continuously in the circumferential direction along the outer peripheral surface of the shaft, and is formed by recessing a predetermined range including a region facing the protruding seal by a predetermined amount. Yes.
In the present invention, the storage space is formed continuously in the circumferential direction along the outer peripheral surface of the outer case, and is formed by depressing a predetermined range including a region facing the protruding seal by a predetermined amount. ing.
In the present invention, the accommodation space is formed continuously in the circumferential direction along the inner peripheral surface of the end portion on the small diameter side, and is formed by depressing a predetermined range including the protruding seal by a predetermined amount. Yes.
In the present invention, the storage space is formed continuously in the circumferential direction along the inner peripheral surface of the large-diameter end, and is formed by recessing a predetermined range including the protruding seal by a predetermined amount. ing.
In this invention, the area | region for clamping the inner peripheral surface of the said small diameter side edge part to the outer peripheral surface of the said shaft by the said fastening member is provided in the both sides of the axial direction of the said accommodation space.
In this invention, the area | region for clamping the inner peripheral surface of the said large diameter side edge part to the outer peripheral surface of the said outer case by the said fastening member is provided in the both sides of the axial direction of the said accommodation space.
In the present invention, when the small-diameter side end is mounted on the shaft, positioning means is provided for positioning the protruding seal in a state of being accommodated in the accommodating space.

According to the present invention, the sealing performance between the constant velocity joint resin boot and the constant velocity joint shaft or outer case can be easily and low-cost even in an atmosphere where high and low temperatures are repeated. In addition, the sealing performance can be maintained for a long time.

Hereinafter, a seal structure according to an embodiment of the present invention will be described with reference to FIGS. 1A to 1E and FIG. In the present embodiment, the resin boot 4 attached to the constant velocity joint 2 is formed by tightening both ends of the boot 4 with the fastening members 6 and 8 and the shaft 2a of the constant velocity joint 2 and the outer case (both the gear housing). It is fastened to 2b. For example, a thermoplastic resin such as a polyester-based thermoplastic elastomer can be applied as the resin as the molding material of the boot 4, but other molding materials may be used.

As shown in FIG. 1A, the boot 4 is provided with a hollow cylindrical small-diameter side end portion P1 on one end side thereof, and the boot 4 has a larger end on the other end side than the small-diameter side end portion P1. A hollow cylindrical large-diameter end P3 having a diameter is provided. In this case, the small diameter side end P1 is fastened to the shaft 2a of the constant velocity joint 2 by a small diameter side fastening member 6 (hereinafter referred to as a small diameter side fastening band), while the large diameter side end P3 is It is fastened to the outer case 2b of the constant velocity joint 2 by a fastening member 8 (hereinafter referred to as a large-diameter side fastening band).

Further, between the small-diameter side end P1 and the large-diameter side end P3, a hollow conical bellows that elastically deforms following a relative angular change between the shaft 2a of the constant velocity joint 2 and the outer case 2b. Part P2 is provided. The bellows portion P2 has a divergent shape extending from the annular shoulder portion K continuous to the small diameter side end portion P1 toward the large diameter side end portion P3, and a plurality of annular mountain portions M and annular valley portions V are alternately combined. Configured. Thereby, the bellows part P2 is maintained in a state in which it can be elastically deformed elastically.

The small diameter side end portion P1 and the large diameter side end portion P3 are provided with

band mounting portions

6p and 8p for mounting the small diameter side fastening band 6 and the large diameter side fastening band 8, respectively. By attaching and tightening the small-diameter side fastening band 6 and the large-diameter side fastening band 8 respectively to the

band attaching portions

6p and 8p, the small-diameter side end portion P1 can be fastened to the shaft 2a of the constant velocity joint 2. At the same time, the large-diameter end P3 can be fastened to the outer case 2b of the constant velocity joint 2. Thereby, the boot 4 can be attached to the constant velocity joint 2.

The seal structure of the present embodiment has a small diameter side end portion P1 (band mounting portion 6p) of the boot 4 fastened to each other by the small diameter side fastening band 6 and the shaft 2a of the constant velocity joint 2, and a large diameter. A large-diameter side end portion P3 (band mounting portion 8p) of the boot 4 fastened to each other by the side fastening band 8 and the outer case 2b of the constant velocity joint 2 can be formed. In this case, since both the seal structures can have the same configuration, as an example, between the small diameter side end portion P1 (band mounting portion 6p) of the boot 4 and the shaft 2a of the constant velocity joint 2 below. A seal structure configured as described above will be described.

As shown in FIGS. 1B to 1E, the boot 4 is continuous in the circumferential direction along the inner peripheral surface Ps of the region (the band mounting portion 6p of the small diameter side end portion P1) to be tightened by the small diameter side fastening band 6. In addition, a projecting seal 10 is provided in which the inner peripheral surface Ps is formed by partially projecting at least one portion in the central direction. As an example, one protruding seal 10 is shown in the drawing.
The protruding seal 10 protrudes in a direction substantially perpendicular to the inner peripheral surface Ps when the boot 4 is not attached to the constant velocity joint 2, and the small diameter side end portion P1 of the boot 4 is formed. When mounted on the shaft 2a of the constant velocity joint 2 and accommodated in the accommodation space 12 described later, the elastic joint is formed so as to be easily bent by elastic deformation.

On the other hand, on the outer peripheral surface 2s of the shaft 2a of the constant velocity joint 2, the small diameter side end portion P1 (band mounting portion 6p) of the boot 4 and the shaft 2a are fastened together by the small diameter side fastening band 6. An accommodation space 12 in which the cylindrical seal 10 is accommodated by being bent by elastic deformation is provided.

Here, the protruding seal 10 has a protruding end 10t in a state in which the small diameter side end portion P1 (band mounting portion 6p) and the shaft 2a are fastened to each other by the small diameter side fastening band 6 (hereinafter referred to as a band fastened state). The side surface (10a or 10b) from the side to the inner peripheral surface Ps side is curved by elastic deformation with respect to the outer peripheral surface 2s of the shaft 2a (in the present embodiment, a storage space constituting surface 12s of the storage space 12 described later). The outer circumferential surface 2s of the shaft 2a (in the present embodiment, a housing space constituting surface 12s of the housing space 12 described later) is pressed against the outer surface 2s of the shaft 2a to maintain a predetermined surface pressure.
Further, in the projecting seal 10, deformation due to thermal expansion and contraction caused by a change in the ambient temperature of the usage environment is caused by a change in the curved state of the projecting seal 10, a positional deviation on the projecting end 10 t side of the projecting seal 10, etc. Is configured to be acceptable.
For this reason, in the present embodiment, unlike the conventional case, deformation due to thermal expansion of the projecting seal 10 is not restricted by the band fastening force and is allowed in the housing space 12 of the shaft 2a. It is the structure which can suppress generation | occurrence | production of the "stickiness" of the shape seal 10 as much as possible.

More specifically, the projecting seal 10 has a first side face 10a facing the large diameter side end portion P3 of the boot 4 and a second side face 10b facing the opposite side. The first side surface 10a is smoothly continuous from the protruding end 10t to the inner peripheral surface Ps of the small diameter side end portion P1 (band mounting portion 6p), while the second side surface 10b is connected to the small diameter side end portion from the protruding end 10t. It is smoothly continuous over the inner peripheral surface Ps of P1 (band mounting portion 6p).

In this case, the continuous portion Ra between the first side surface 10a and the inner peripheral surface Ps and the continuous portion Rb between the second side surface 10b and the inner peripheral surface Ps are rounded with a predetermined radius of curvature R, respectively. It is preferable to set the shape. Thereby, when the projecting seal 10 is elastically deformed, it is possible to avoid stress concentration in each of the continuous portions Ra and Rb. In addition, since the curvature radius R of each continuous site | part Ra and Rb is arbitrarily set, for example according to the magnitude | size, shape, etc. of the protruding seal 10, there is no numerical limitation in particular here.

Further, the shape of the protruding seal 10 is such that the distance between the first side surface 10a and the second side surface 10b gradually (continuously) decreases from the respective continuous portions Ra and Rb toward the protruding end 10t, for example. The shape may be any shape such as a tapered shape or a straight shape in which the distance between the first side surface 10a and the second side surface 10b is constant from the respective continuous portions Ra and Rb toward the protruding end 10t. it can. 1B, FIG. 1D, FIG. 1E, and FIG. 2 show a tapered projecting seal 10 as an example, but this is only an example, and the technical scope of the invention is not limited thereby. Absent. In any case, it is preferable that the projecting end 10t has a semicircular arc shape that is rounded.

Further, the thickness W of the projecting seal 10 is defined by the distance between the first side surface 10a and the second side surface 10b, but the average thickness W including the tapered shape and the straight shape described above (for example, Assuming a thickness W of the center position of the protruding length described later, the protruding seal 10 is preferably set to a thickness W that can be elastically deformed by a force applied to the protruding end 10t side, for example. . Specifically, the thickness W of the protruding seal 10 is such that, in the band fastening state, the first side surface 10a or the second side surface 10b constituting the protruding end 10t side is the outer peripheral surface 2s of the shaft 2a (this embodiment). In this case, the thickness W is set to a thickness W that abuts against a housing space constituting surface 12s) of the housing space 12 to be described later and is curved by elastic deformation and can be pressed by an elastic restoring force to maintain a predetermined surface pressure. Note that the thickness W of the projecting seal 10 is arbitrarily set according to the size and shape of the projecting seal 10 and the projection length H, which will be described later. Further, regarding the thickness W of the projecting seal 10, even when the projecting seal 10 is thermally expanded in a high temperature atmosphere, the deformation due to the thermal expansion is caused by the change in the curved state of the projecting seal 10 itself. Further, the thickness W is set such that it can be tolerated by the positional deviation on the protruding end 10t side.

The protruding length H of the protruding seal 10 is the length from the inner peripheral surface Ps of the band mounting portion 6p to the protruding end 10t at the small diameter side end portion P1 of the boot 4 (or in a direction perpendicular to the inner peripheral surface Ps). In this case, the protruding seal 10 has a side surface (10a or 10b) constituting the protruding end 10t side of the outer peripheral surface 2s of the shaft 2a (described later in this embodiment). The protrusion length H is set so as to be in contact with the storage space constituting surface 12s) of the storage space 12 and to bend by elastic deformation, and to be kept in contact with the elastic restoring force to maintain a predetermined surface pressure.
Specifically, the projecting length H of the projecting seal 10 is the projecting length H that can accommodate the projecting seal 10 in the accommodating space 12 described later in the band fastening state, and in this state, the projecting end The protruding length H may be set such that the side surface (10a or 10b) constituting the 10t side is elastically deformed and pressed against the outer peripheral surface 2s (accommodating space forming surface 12s described later) of the shaft 2a. The protruding length H of the projecting seal 10 is arbitrarily selected according to, for example, the size and shape of the projecting seal 10, the above-described thickness W, the size of the accommodating space 12 described later, and the shape of the accommodating space constituting surface 12s. Since it is set, the numerical value is not particularly limited here.

The protruding direction of the protruding seal 10 is shown in FIGS. 1B, 1D, 1E, and 2 as an example, but the protruding seal 10 protruding in the direction perpendicular to the inner peripheral surface Ps is shown. For example, it may be inclined toward the large diameter side end portion P3 of the boot 4 or may be inclined toward the opposite side. As an example, FIG. 4A shows a protruding seal 10 that is inclined toward the large-diameter side end portion P3 of the boot 4. Here, a reference plane X extending in a direction perpendicular to the inner peripheral surface Ps is assumed, and as an inclination direction of the projecting seal 10, an inclination passing through the projecting end 10t and the central portion of each continuous portion Ra, Rb. Assuming the axis Y, the inclination angle θ of the protruding seal 10 can be defined as the angle formed by the inclination axis Y with respect to the reference plane X. In this case, the inclination angle θ is arbitrarily set according to, for example, the self-sealing effect described later or the ease of mounting the small diameter side end portion P1 of the boot 4 to the shaft 2a. There is no particular numerical limitation.

On the other hand, the accommodating space 12 is formed continuously in the circumferential direction along the outer peripheral surface 2s of the shaft 2a, and is formed by depressing a predetermined range including a region facing the protruding seal 10 by a predetermined amount. ing. The housing space 12 has a housing space constituting surface 12s formed so as to be recessed from the outer peripheral surface 2s of the shaft 2a. In this case, in the band fastening state, the projecting seal 10 is accommodated between the housing space constituting surface 12s and the inner peripheral surface Ps of the small diameter side end portion P1 (band mounting portion 6p). The accommodating space 12 is configured such that the protruding end 10t side can be bent by elastic deformation.

Here, the size and shape of the accommodation space 12 can be arbitrarily set according to the amount of depression and the shape of the depression of the accommodation space constituting surface 12s. In FIG. 1B, FIG. 1C, and FIG. 2, as an example, the accommodation space 12 in which the accommodation space constituting surface 12s is recessed in an arc shape is shown. However, the present invention is not limited to this. For example, the housing space constituting surface 12s can be recessed. In short, the accommodation space constituting surface 12s may be set so that the accommodation space 12 has a size and shape that can accommodate the protruding seal 10 in the band fastening state. In this case, the depression amount and the depression shape of the accommodation space constituting surface 12 s can be accommodated by the protruding seal 10 being curved and elastically deformable in the band fastening state, and constitute the protruding end 10 t side of the protruding seal 10. The side surface (10a or 10b) may be set so that a predetermined surface pressure can be maintained by pressing against the housing space constituting surface 12s with an elastic restoring force.

In addition, the amount of depression of the housing space constituting surface 12s is determined by the bottom surface (reference numeral is omitted) of the housing space constituting surface 12s where the protruding end 10t side of the projecting seal 10 is in pressure contact with the outer peripheral surface 2s of the shaft 2a. Is defined as a recess amount G (see FIG. 1C) between the two, and the recess amount G depends on, for example, the protruding length H (the length from the inner peripheral surface Ps to the protruding end 10t) of the protruding seal 10 described above. Therefore, the numerical value is not particularly limited here. Further, with respect to the shape of the accommodation space constituting surface 12s, at least the shape of the bottom surface of the accommodation space constituting surface 12s corresponding to the depression amount G can be accommodated while the protruding seal 10 is elastically deformed and accommodated in a band fastening state. In addition, the side surface (10a or 10b) constituting the protruding end 10t side of the projecting seal 10 may be set so as to be able to maintain a predetermined surface pressure by pressing against the housing space constituting surface 12s with an elastic restoring force.

Moreover, the position which comprises the seal structure of this Embodiment is the small diameter side edge part P1 (band mounting part 6p) by the small diameter side fastening band 6 on both sides of the protruding seal 10 and the accommodation space 12 in a band fastening state. It is preferable to set so as to secure fastening regions F1 and F2 (see FIG. 1B) for fastening the inner peripheral surface Ps to the outer peripheral surface 2s of the shaft 2a. In the figure, a fastening region F1 is secured on the large diameter side end portion P3 side of the boot 4, and a fastening region F2 is secured on the opposite side. The sizes (ranges) of the tightening regions F1 and F2 are arbitrarily set in consideration of, for example, the ratio of the accommodation space 12 to the entire outer peripheral surface 2s of the shaft 2a. .

Further, the seal structure of the present embodiment is provided with positioning means for positioning the protruding seal 10 in a state in which it is accommodated in the accommodating space 12 when the boot 4 is attached to the shaft 2 a of the constant velocity joint 2. . As positioning means, the inner peripheral surface Ps of the small-diameter side end portion P1 (band mounting portion 6p) is provided with a projecting portion 14 formed by projecting a part thereof inward (center direction), and a shaft. The outer peripheral surface 2s of 2a is provided with a recess 16 in which the protrusion 14 is recessed so as to be engageable. In this case, it is preferable that the protrusion part 14 and the hollow part 16 are comprised continuously along the circumferential direction.

It should be noted that the positioning means shown in FIGS. 1B to 1D are merely examples, and the technical scope of the invention is not limited thereby. For example, contrary to the configuration of FIGS. 1B to 1D, a recess (not shown) is provided on the inner peripheral surface Ps of the small-diameter side end portion P1 (band mounting portion 6p), and a projecting portion (not shown) is formed on the outer peripheral surface 2s of the shaft 2a. (Not shown) may be provided. Further, the shape of the protruding portion 14 and the recessed portion 16 can be arbitrarily set as long as it is a shape that can be engaged with each other such as an elliptical shape or a rectangular shape other than the circular arc shape as shown in FIGS. 1B to 1D. . Furthermore, the arrangement of the positioning means is not limited to the arrangement shown in FIGS. 1B to 1D, and can be arbitrarily set as long as it can form the protrusions 14 and the depressions 16. Further, whether or not the positioning means is provided is also arbitrary.

As described above, according to the present embodiment, when the boot 4 is attached to the constant velocity joint 2, when the small diameter side end portion P1 of the boot 4 is assembled to the shaft 2a of the constant velocity joint 2, the small diameter side end portion P1 (band attachment) By engaging the protrusion 14 formed on the inner peripheral surface Ps of the portion 6p) with the recess 16 formed on the outer peripheral surface 2s of the shaft 2a, the small-diameter end P1 (band mounting portion 6p) The protruding seal 10 formed on the inner peripheral surface Ps can be accurately positioned in the accommodation space 12 formed on the outer peripheral surface 2s of the shaft 2a. Further, since the protruding end 10t of the protruding seal 10 has a semicircular arc shape, when the small diameter side end portion P1 is assembled to the shaft 2a, the protruding end 10t and the outer peripheral surface 2s of the shaft 2a The frictional resistance due to the sliding contact can be reduced. Thereby, the small diameter side edge part P1 can be assembled | attached smoothly to the shaft 2a.

In this state, the projecting seal 10 is bent by elastic deformation and stored in the storage space 12. In this state, when the small diameter side end portion P1 (band mounting portion 6p) and the shaft 2a are fastened to each other by the small diameter side fastening band 6, the fastening force of the small diameter side fastening band 6 at this time is a projecting seal. 10 and the tightening regions F1 and F2 secured on both sides of the accommodating space 12 act substantially equally. Thereby, the inner peripheral surface Ps of the small diameter side end portion P1 (band mounting portion 6p) can be firmly and firmly fixed to the outer peripheral surface 2s of the shaft 2a.
On the other hand, the projecting seal 10 is not crushed by the fastening force of the small-diameter side fastening band 6, and the side surface (10a or 10b) constituting the projecting end 10t side of the projecting seal 10 is the outer peripheral surface 2s of the shaft 2a. In the embodiment, the storage space constituting surface 12s) of the storage space 12 is curved to be elastically deformed and pressed to maintain a predetermined surface pressure.

At this time, the protruding end 10t side of the projecting seal 10 is, for example, as shown in FIG. 2, when the first side surface 10a is curved and pressed against the housing space constituting surface 12s (indicated by a dotted line in the figure). And the second side surface 10b is curved and press-contacted (shown by a solid line in the figure). In any case, due to the elastic restoring force of the protruding seal 10 in the curved state, the side surface (10a or 10b) constituting the protruding end 10t side is pressed against the accommodation space constituting surface 12s of the accommodation space 12 with an optimum surface pressure. To do. Thereby, a sealing effect is exhibited and grease leakage can be reliably prevented.

Here, when the second side surface 10b constituting the protruding end 10t side is curved and pressed against the accommodating space constituting surface 12s, for example, the inner peripheral surface Ps of the small diameter side end portion P1 (band mounting portion 6p) and the shaft The grease that has entered the housing space 12 through the space between the outer peripheral surface 2s of 2a is concentrated on the projecting end 10t side along the first side surface 10a of the projecting seal 10 as indicated by the arrow T in FIG. . At this time, if the internal pressure of the grease is applied to the protruding end 10t side, the surface pressure of the second side surface 10b with respect to the housing space constituting surface 12s is increased, and the so-called self-sealing effect can be exhibited. In the specification that preferentially exhibits such an effect, the protruding direction of the protruding seal 10 may be set to an inclination angle θ as shown in FIG. 4A, for example. According to such a self-sealing structure, the boot 4 used in a high-temperature atmosphere can be made compact, the shaft 2a can be changed at a high angle, and the internal pressure of the grease can be increased due to the longer stroke of the constant velocity joint 2.

Further, in the band fastening state described above, in the accommodation space 12, the side surface (10a or 10b) constituting the protruding end 10t side of the projecting seal 10 is curved to be elastically deformable with respect to the accommodation space constituting surface 12s of the shaft 2a. It is in pressure contact. For this reason, when used in an atmosphere where high and low temperatures are repeated, even when the protruding seal 10 is thermally expanded in a high temperature atmosphere, the thermal expansion is allowed in the accommodation space 12 and is fastened as in the conventional case. The thermal expansion of the protruding seal 10 is not restricted by the force.
In this case, as shown by the solid line in FIG. 5, the protruding seal 10 that has thermally expanded can be further curved by the protruding end 10 t side being displaced along the accommodating space constituting surface 12 s. As a result, it is possible to suppress the occurrence of “sagging” due to compression set as in the conventional case to the protruding seal 10 including the side surface (10a or 10b) constituting the protruding end 10t side as much as possible. In addition, the broken line in FIG. 5 has shown the accommodation state of the protruding seal | sticker 10 after heat shrink in a low-temperature atmosphere. FIG. 5 illustrates the specifications of the protruding seal 10 in which one side surface 10b on the protruding end 10t side is in pressure contact with the housing space constituting surface 12s. On the contrary, although not particularly illustrated, the protruding end 10t Even in the specification of the protruding seal 10 in which the other side surface 10a on the side is in pressure contact with the housing space constituting surface 12s, it is possible to suppress the occurrence of “sagging” due to compression set as in the past as much as possible.

Thus, according to the seal structure in which the occurrence of “sagging” of the projecting seal 10 is prevented, the side surface (10a) constituting the protruding end 10t side in use in an atmosphere where high and low temperatures are repeated. Alternatively, the surface pressure with respect to the housing space constituting surface 12s of 10b) can be kept constant over a long period of time without being lowered as in the prior art. Thereby, the sealing performance between the boot 4 and the shaft 2a can be maintained over a long period of time, and it is possible to prevent the occurrence of grease leakage and the entry of dust and water from the outside.

Further, according to the seal structure of the present embodiment, the projecting seal 10 can be formed at the same time by a series of manufacturing processes of the boot 4, and the accommodation space 12 only needs to be recessed on the outer peripheral surface 2s of the shaft 2a. Thereby, a seal structure can be constructed more easily and at a lower cost than in the past.

Further, the present invention is not limited to the above-described embodiment, and the following modifications are also within the technical scope of the present invention, and the same effects can be realized. In the following description, only the specific configuration of this modification will be described.

As shown in FIGS. 3A and 3B, in the seal structure according to this modification, the accommodation space 12 is continuous in the circumferential direction along the inner peripheral surface Ps of the small diameter side end portion P1 (band mounting portion 6p) of the boot 4. And a predetermined range including the protruding seal 10 is recessed by a predetermined amount. The protruding seal 10 described in detail in the above embodiment is continuous in the circumferential direction along the accommodation space 12 and inward (center direction) beyond the inner circumferential surface Ps from the accommodation space 12. Protrusively formed.

In this modification, the storage space 12 has a storage space constituting surface 12s formed by being recessed from the inner peripheral surface Ps of the small diameter side end portion P1 (band mounting portion 6p). In this case, in the band fastening state, the accommodation space 12 in which the protruding seal 10 is curved and accommodated by elastic deformation is configured between the accommodation space constituting surface 12s and the outer peripheral surface 2s of the shaft 2a. In addition, since the size and shape of the accommodation space 12 can be configured in the same manner as in the above embodiment, the description thereof is omitted.

Further, the protruding length H of the projecting seal 10 is such that, in the band fastening state, the side surface (10a or 10b) constituting the projecting end 10t side comes into contact with the outer peripheral surface 2s of the shaft 2a and is bent by elastic deformation, and elastically restored. The protrusion length H is set so as to maintain a predetermined surface pressure by pressure contact. As an example, FIG. 3A shows a state in which the second side surface 10b on the protruding end 10t side is in contact with the outer peripheral surface 2s of the shaft 2a and is curved and pressed by elastic deformation in the band fastening state. Yes.

As an example of the protruding direction of the protruding seal 10, FIG. 3B shows the protruding seal 10 protruding in a direction perpendicular to the inner peripheral surface Ps of the small diameter side end portion P <b> 1 (band mounting portion 6 p). However, it is not limited to this, for example, you may incline toward the large diameter side edge part P3 side of the boot 4, or may incline toward the opposite side. FIG. 4B shows, as an example, a protruding seal 10 that is inclined toward the large-diameter side end portion P3 of the boot 4. In addition, since the inclination angle θ of the protruding seal 10 can be configured in the same manner as in the above-described embodiment, the description thereof is omitted.

Here, in the seal structure according to this modification, the shaft 2a can be used as it is without any processing including the outer peripheral surface 2s. In addition, the cost of the seal structure can be further reduced by the amount that processing on the shaft 2 is unnecessary.

Further, in this modification, the seal structure including the projecting seal 10 and the accommodation space 12 is provided only in the boot 4, and the invention as the boot 4 alone can be obtained. Then, the second side surface 10b on the protruding end 10t side is curved by elastic deformation with respect to the outer peripheral surface 2s of the shaft 2a only by assembling the small diameter side end portion P1 of the boot 4 to an arbitrary portion of the outer peripheral surface 2s of the shaft 2a. And can be pressed. Thereby, the freedom degree of the assembly | attachment of the small diameter side edge part P1 of the boot 4 with respect to the shaft 2a can be improved. In this case, since the positioning means applied in the above-described embodiment can be eliminated, the cost of the seal structure can be further reduced.

Moreover, in the said one Embodiment and modification, when the accommodation space 12 is comprised in either one of the outer peripheral surface 2s of the shaft 2a, or the inner peripheral surface Ps of the small diameter side edge part P1 (band mounting part 6p) of the boot 4 However, the present invention is not limited to this, and the storage space 12 may be provided on both sides.

In the embodiment and the modification described above, the seal structure configured between the small diameter side end portion P1 (band mounting portion 6p) of the boot 4 and the shaft 2a of the constant velocity joint 2 has been described. Needless to say, the seal structure can be applied between the large-diameter side end P3 (band mounting portion 8p) of the boot 4 and the outer case 2b of the constant velocity joint 2 without being limited.

In the above-described embodiment and modification, the description has been made assuming a single seal structure including one projecting seal 10 and a storage space 12 corresponding thereto, but the present invention is not limited to this. Two or more seal structures may be provided.
Furthermore, one seal structure (one accommodating space 12) may be provided, and a plurality of protruding seals 10 accommodated in the accommodating space 12 may be provided in the axial direction.

The figure which shows the structure of the constant velocity joint and resin boot to which the seal structure which concerns on one embodiment of this invention was applied. Sectional drawing which expands and partially shows the structure of the seal structure between the small diameter side end part of a boot, and the shaft of a constant velocity joint in the state fastened mutually by the small diameter side fastening band. Sectional drawing which expands and partially shows the structure of the outer peripheral surface of the shaft in which the accommodation space was formed. Sectional drawing which expands and partially shows the structure of the internal peripheral surface of the small diameter side edge part in which the protruding seal was formed. FIG. 1D is a cross-sectional view showing a partially enlarged configuration of the protruding seal shown in FIG. 1D. Sectional drawing which expands partially and shows the state which the side surface which comprises the front end side of a projecting seal contact | abuts the accommodation space structural surface of accommodation space, and was curved and pressed by elastic deformation. The seal structure according to the modification of the present invention is partially enlarged in the structure of the seal structure between the small diameter side end portion of the boot and the shaft of the constant velocity joint in a state where they are fastened together by the small diameter side fastening band. FIG. Sectional drawing which partially enlarges and shows the structure of the internal peripheral surface of the small diameter side edge part in which the accommodation space and the protruding seal were formed together. Sectional drawing which expands and partially shows the structure of the projecting seal inclined toward the large diameter side edge part side of a boot in the seal structure which concerns on one embodiment of this invention. Sectional drawing which expands partially the structure of the protruding seal | sticker inclined toward the large diameter side edge part side of a boot in the seal structure which concerns on the modification of this invention. The typical sectional view which expands and shows the deformation state at the time of a projection seal thermally expanding and contracting in the atmosphere where high temperature and low temperature are repeated.

2a Shaft 2s Shaft outer peripheral surface 4 Resin boot 6 Small diameter side fastening band (fastening member)
6p Band mounting part (area to be tightened by fastening member)
Inner circumferential surface 10 of Ps band mounting part Protruding seal 12 Housing space

Claims

In a state where one end of the resin boot for the constant velocity joint is fastened to the constituent member of the constant velocity joint by the fastening member, the seal structure is configured between the end and the constituent member,
The end portion is provided with a projecting seal that is continuous in the circumferential direction along the inner circumferential surface of the region to be tightened by the fastening member and protrudes in the central direction from the inner circumferential surface,
At least one of the inner peripheral surface of the end portion and the outer peripheral surface of the component member accommodates the projecting seal curved by elastic deformation in a state where the end portion is fastened to the component member by the fastening member. Storage space is provided,
The seal structure is characterized in that the projecting seal is allowed to be elastically deformed by thermal expansion and contraction in the accommodation space while maintaining a state in pressure contact with the component member.
The end portion is a small-diameter side end portion of the resin boot for the constant velocity joint,
The component is a shaft of the constant velocity joint;
In the state where the small diameter side end is fastened to the shaft by a fastening member, the seal structure is configured between the small diameter side end and the shaft,
The small-diameter side end is provided with a projecting seal that is continuous in the circumferential direction along the inner peripheral surface of the region to be tightened by the fastening member, and protrudes in the center direction from the inner peripheral surface,
At least one of the inner peripheral surface of the small-diameter end and the outer peripheral surface of the shaft is bent by elastic deformation when the small-diameter end is fastened to the shaft by the fastening member. Storage space is provided,
2. The seal structure according to claim 1, wherein the protruding seal is allowed to be elastically deformed by thermal expansion and contraction in the accommodation space while maintaining a state of being pressed against the shaft.
The end is a large-diameter side end of the resin boot for the constant velocity joint,
The component member is an outer case of the constant velocity joint,
In a state where the large-diameter side end is fastened to the outer case by a fastening member, the seal structure is configured between the large-diameter side end and the outer case,
The large-diameter side end is provided with a projecting seal that is continuous in the circumferential direction along the inner circumferential surface of the region to be tightened by the fastening member, and protrudes in the center direction from the inner circumferential surface,
At least one of the inner peripheral surface of the large-diameter side end and the outer peripheral surface of the outer case is elastic in that the projecting seal is elastic when the large-diameter end is fastened to the outer case by the fastening member. An accommodation space that is curved and accommodated by deformation is provided,
2. The seal structure according to claim 1, wherein the projecting seal is allowed to be elastically deformed by thermal expansion and contraction in the housing space while maintaining a state in pressure contact with the outer case.
The housing space is formed continuously in the circumferential direction along the outer peripheral surface of the shaft, and is formed by depressing a predetermined range including a region facing the protruding seal by a predetermined amount. The seal structure according to claim 2.
The accommodating space is formed continuously in the circumferential direction along the outer peripheral surface of the outer case, and is formed by depressing a predetermined range including a region facing the protruding seal by a predetermined amount. The seal structure according to claim 3, wherein the seal structure is characterized.
The accommodation space is formed continuously in the circumferential direction along the inner peripheral surface of the end portion on the small diameter side, and is formed by recessing a predetermined range including the protruding seal by a predetermined amount. The seal structure according to claim 2.
The housing space is formed continuously in the circumferential direction along the inner peripheral surface of the end portion on the large diameter side, and is formed by depressing a predetermined range including the protruding seal by a predetermined amount. The seal structure according to claim 3, wherein the seal structure is characterized.
The area | region for clamping the inner peripheral surface of the said small diameter side edge part to the outer peripheral surface of the said shaft by the said fastening member is provided in the both sides of the axial direction of the said accommodation space, The 2, 4 characterized by the above-mentioned. Or the sealing structure of any one of 6.
The area | region for clamping the internal peripheral surface of the said large diameter side edge part to the outer peripheral surface of the said outer case by the said fastening member is provided in the both sides of the axial direction of the said accommodation space, The 3rd aspect is provided. The seal structure according to any one of 5 and 7.
7. The positioning device according to claim 2, further comprising positioning means for positioning the projecting seal in a state of being accommodated in the accommodation space when the small diameter side end is attached to the shaft. The seal structure according to any one of the above.