JP2006336711A - Boot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boot capable of suppressing the falling of one transmission shaft from the inside of the outer case of the other transmission shaft of a constant velocity joint. <P>SOLUTION: This boot 10 comprises an extension part 4 formed between a large diameter mounting part 2 and a bellows part 3. A distance dimension between an axis O and the tip 4a of the extension part 4 in the extending direction is set shorter than a distance dimension L2 between the axis O and the end face of a roller member 53. When the transmission shafts 50 and 60 are moved (extended) in the directions that they are apart from each other, the roller member 53 is allowed to abut on the extension part 4 to restrict the relative movements of the transmission shafts 50 and 60. As a result, the falling of the tip parts (roller member 53 and others) from the inside of the outer case 61 can be suppressed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  According to the present invention, a plurality of guide grooves are recessed in the inner peripheral surface of the outer case of one transmission shaft, and a plurality of projecting portions projecting from the other transmission shaft are provided in the plurality of guide grooves, respectively. With regard to boots that are fitted to constant velocity joints that can be expanded and contracted in the axial direction and capable of transmitting rotational force by being fitted, particularly that the other transmission shaft falls off from the outer case of one transmission shaft. The present invention relates to a boot that can be suppressed.

  One of the constant velocity joints used in the drive shafts (propeller shafts) and propulsion shafts of automobiles, etc., is a tripod type constant velocity that can extend and contract in the axial direction and transmit rotational force. There is a joint.

  As shown in FIGS. 5 and 6, the constant velocity joint CVJ includes three trunnions 51 protruding from the output-side (or input-side) transmission shaft 50 in a direction perpendicular to the axis, and each trunnion 51 includes a plurality of trunnions 51. A ring-shaped roller member 53 is fitted over the needle bearing 52.

  On the other hand, a cylindrical outer case 61 having an opening is fixed to the transmission shaft 60 on the input side (or output side). Three guide grooves 61a extend in the axial direction (left and right direction in FIG. 5) on the inner peripheral surface of the outer case 61, and the roller member 53 is slidably fitted into the guide groove 61a. ing.

  A boot 100 is attached to the connecting portion of the constant velocity joint CVJ. In the boot 100, a large-diameter attachment portion 101 and a small-diameter attachment portion 102 are externally fitted to the outer case 60 and the transmission shaft 50, respectively, and are fastened and fixed by a fastening band 80. In addition, a bellows portion 103 is formed between the large-diameter mounting portion 101 and the small-diameter mounting portion 102 so that a valley portion and a mountain portion are repeatedly and continuously formed and expandable and contractable in the axial direction (patent). References 1, 2).

According to the constant velocity joint CVJ configured in this way, for example, even when the tire moves up and down and the effective length of the drive shaft changes, the roller member 53 slides along the guide groove 61a. Thus, the transmission shafts 50 and 60 can be relatively repositioned (expanded in the axial direction) to absorb the change in the effective length of the drive shaft.
JP-A-2005-121122 JP-A-2005-113828

  By the way, in the constant velocity joint CVJ, first, in the mounting process, the transmission shafts 50 and 60 are connected to each other, and the boot 100 is mounted and fixed to the connecting portion and assembled. This assembly is then transported to the assembly process and assembled to the vehicle.

  However, in the above-described conventional configuration, when the assembly is tilted during conveyance from the mounting process to the assembling process or when assembling to the vehicle, the transmission shaft 50 causes the outer case 60 to move due to its own weight. There was a problem that it would easily fall out of the inside.

  Therefore, when transporting an assembly or assembling it to a vehicle, it is necessary to transport and assemble while maintaining the posture of the assembly to prevent the above-mentioned dropout. There was a problem of causing deterioration. In addition, when the above-described dropout occurs, it is necessary to perform the connecting operation of the transmission shafts 50 and 60 again, which not only increases the man-hours, but also causes the fall of the yield due to damage to the boots 100 due to the fallen transmission shaft 50. There was also a point.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a boot that can prevent the other transmission shaft from falling off from the outer case of one transmission shaft.

  In order to achieve this object, the boot according to claim 1 is provided with a plurality of guide grooves recessed in the inner peripheral surface of the outer case of one transmission shaft, and the other transmission shaft in the plurality of guide grooves. A plurality of projecting portions projecting from the boot, each of which is fitted to a constant velocity joint configured to expand and contract in the axial direction and transmit a rotational force, A large-diameter attachment portion attached to the outer case of one transmission shaft, a small-diameter attachment portion attached to the other transmission shaft of the constant velocity joint, the large-diameter attachment portion and the small-diameter attachment portion are connected to each other and And a bellows part that is continuously and repeatedly formed in the axial direction, and is located between the large-diameter attachment part and the bellows part, the large-diameter attachment From the inner peripheral surface side of the part A projecting portion formed to project toward the other transmission shaft, and a distance dimension from the shaft core to the projecting direction tip of the projecting portion is from the shaft core to the projecting direction tip of the projecting portion. The distance dimension is set to be shorter than the distance dimension, and when the one transmission shaft and the other transmission shaft are moved relative to each other in a direction away from each other, the projecting portion is configured to abut against the projecting portion. ing.

  The boot according to claim 2 is the boot according to claim 1, wherein the large-diameter mounting portion, the overhanging portion, the bellows portion, and the small-diameter mounting portion are integrally formed of a resin material.

  The boot according to claim 3 is the boot according to claim 1 or 2, wherein a plurality of recesses are dispersed in the circumferential direction on the outer peripheral surface of the outer case, and the large-diameter mounting portion is A plurality of bulging portions projecting from an inner peripheral surface of the large-diameter mounting portion are provided, and the plurality of bulging portions are configured to be fitted into the plurality of concave portions, respectively, and the protruding direction of the protruding portion The tip is configured in a circular shape having the same concentric diameter as a virtual circle that contacts each of the plurality of bulging portions in the axial direction view.

  According to a fourth aspect of the present invention, in the boot according to any one of the first to third aspects, the thickness dimension of the overhanging portion is thicker than the thickness dimension of the bellows portion.

  The boot according to claim 5 is the boot according to any one of claims 1 to 4, wherein the projecting portion projects from the other transmission shaft in a direction perpendicular to the axis, and is freely movable to the trunnion. An annular roller member that is externally fitted to the roller member, and the trunnion tip is configured to project from the end surface of the roller member, and the distance dimension from the shaft core to the tip of the overhang portion in the overhang direction is The distance dimension from the shaft core to the end surface of the roller member is set to a distance dimension longer than the distance from the shaft core to the front end in the projecting direction of the projecting portion. The distance dimension is set to be shorter than the distance dimension to the tip.

  The boot according to claim 6 is the boot according to any one of claims 1 to 4, wherein the projecting portion projects from the other transmission shaft in a direction perpendicular to the axis, and is freely movable to the trunnion. An annular roller member that is externally fitted to the roller member, and the trunnion tip is configured to project from the end surface of the roller member, and the distance dimension from the shaft core to the tip of the overhang portion in the overhang direction is The distance dimension is set shorter than the distance dimension from the shaft core to the end face of the roller member.

  The boot according to claim 7 is the boot according to any one of claims 1 to 6, comprising a plurality of connection portions for connecting the first peak of the bellows portion and the overhang portion, and the plurality of connections. The portions are distributed in the circumferential direction.

  According to the boot of claim 1, an overhang is formed between the large-diameter mounting portion and the bellows portion, and the distance dimension from the shaft core to the tip in the overhang direction of the overhang portion is set to the protruding portion. Since the distance dimension is set to be shorter than the distance dimension to the front end of the projecting direction, when one transmission shaft and the other transmission shaft are moved relative to each other, the projecting direction of the other transmission shaft There is an effect that it is possible to prevent the other transmission shaft from falling out from the outer case of one transmission shaft by bringing the portion into contact with the overhanging portion.

  Therefore, there is no need to carry and carry assembly work while maintaining the posture of the assembly as in the past, and the freedom of assembly posture during transportation and assembly can be expanded, improving workability. There is an effect that can be achieved.

  Moreover, if the above-mentioned dropout can be suppressed, the useless work of reinserting and connecting the fallen transmission shaft into the outer case and the problem that the fallen transmission shaft damages the bellows portion of the boot in advance. Since this can be avoided, there is an effect that the man-hours can be reduced and the yield can be improved as compared with the conventional product.

  According to the boot of claim 2, in addition to the effect of the boot of claim 1, the large-diameter mounting portion, the overhanging portion, the bellows portion, and the small-diameter mounting portion are integrally formed from a resin material. As a result, it is possible to achieve a reduction in weight as well as to provide sufficient rigidity to the overhanging portion. As a result, there is an effect that the other transmission shaft can be reliably suppressed from falling out of the outer case.

  That is, the prevention of dropout of the transmission shaft by the overhanging portion cannot be achieved with a conventional boot made of a rubber material due to insufficient rigidity or an increase in weight, and is achieved for the first time by using a resin material as in the present invention. As a result, the weight of the entire boot and the securing of the rigidity of the overhanging portion can be achieved at the same time.

  According to the boot of claim 3, in addition to the effect of the boot of claim 1 or 2, the tip of the overhanging portion is configured to be circular in the axial direction view. The effect that the cooling rate can be made uniform over the entire overhanging portion, the occurrence of distortion can be suppressed, and the difference in cooling rate with respect to the bellows portion and the large-diameter mounting portion can be reduced to suppress the influence thereof. There is. As a result, the shape of the bellows portion and the large-diameter attachment portion can be accurately formed, so that the durability of the bellows portion and the sealing performance of the large-diameter attachment portion can be improved.

  In addition, since the tip of the overhanging portion is configured to be concentric and circular with each of the virtual circles in contact with the plurality of bulging portions when viewed in the axial direction, the shape of the large-diameter mounting portion is accurately formed. Thus, there is an effect that the sealing performance can be further improved.

  That is, since the projecting direction tip of the bulging part and the projecting direction tip of the bulging part can be flush with each other, it is possible to suppress the occurrence of distortion on a part of the surface, and as a result. The inner peripheral surface of the bulging portion can be accurately formed.

  Further, by matching the position of the projecting direction tip of the projecting part with the position of the projecting direction tip of the projecting part, the bottom part of the lightening hole formed in the projecting part (the bellows part side) is partially thickened. Thickness can be prevented. As a result, at the time of molding, the cooling rate of the entire bulging portion can be made uniform, and this also allows the bulging portion to be accurately molded.

  According to the boot of claim 4, in addition to the effect of the boot according to any of claims 1 to 3, the thickness dimension of the overhanging portion is configured to be thicker than the thickness dimension of the bellows portion. There is an effect that sufficient rigidity can be given to the protruding portion. Thereby, since the protruding portion can be firmly received by the overhanging portion, it is possible to reliably suppress the other transmission shaft from falling out of the outer case.

  According to the boot of claim 5, in addition to the effect of the boot according to any one of claims 1 to 4, the distance dimension from the shaft core to the tip of the overhanging portion of the overhang portion Set the distance dimension longer than the distance dimension to the end face, and set the distance dimension from the shaft core to the tip of the overhang portion in the overhang direction to a distance dimension shorter than the distance dimension from the shaft core to the tip of the trunnion. Therefore, when the one transmission shaft and the other transmission shaft are moved relative to each other in a direction away from each other, the overhanging portion can be brought into contact with only the tip end portion of the trunnion (the protruding portion from the roller member). There is an effect that you can.

  That is, since the point of load acting on the overhanging portion can be brought closer to the base side of the overhanging portion, the leverage required for the overhanging portion can be reduced by the lever principle. As a result, since the thickness of the overhanging portion can be set to be thinner, the amount of resin material used can be reduced while reducing the amount of resin material while ensuring prevention of the above-mentioned dropout, and simultaneously reducing the material cost. You can also

  According to the boot described in claim 6, in addition to the effect of the boot according to any one of claims 1 to 4, the distance dimension from the shaft core to the tip of the projecting direction of the projecting portion is determined by the distance between the shaft core and the roller member. Since the distance dimension is set to be shorter than the distance dimension to the end surface, when the one transmission shaft and the other transmission shaft are moved relative to each other in a direction away from each other, the protruding portion is brought into contact with the roller member. There is an effect that can be.

  That is, by allowing the overhanging portion to extend to a position where it reaches the roller member, a sufficiently large allowance between the overhanging portion and the roller member (projecting portion of the other transmission shaft) can be secured. Therefore, even if the overhanging part is pushed by the roller member and warps, the roller member can get over the overhanging part, so that the tip of the trunnion is at the base side of the overhanging part (large-diameter mounting part side). It is possible to reliably prevent the other transmission shaft from falling out of the outer case.

  According to the boot according to claim 7, in addition to the effect of the boot according to any one of claims 1 to 6, the boot includes a plurality of connection portions that connect the first mountain of the bellows portion and the overhang portion. There is an effect that the protruding portion can be received more firmly by increasing the rigidity of the overhanging portion. As a result, it is possible to reliably suppress the other transmission shaft from falling out of the outer case.

  In addition, the rigidity required by the overhanging part itself is reduced by the reinforcement effect of the connecting part, so the thickness of the overhanging part can be set to be thinner, and as a result, the overall weight is reduced. And the material cost can be reduced at the same time.

  Furthermore, by dispersing and arranging the connecting portions in the circumferential direction, at the time of molding, the cooling speed of the connecting portions can be increased and the cooling rate in the vicinity of the connecting portions can be made uniform, so that the overhanging portion As a result, not only the overhanging portion but also the bellows portion and the large-diameter mounting portion can be formed with high accuracy.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. Fig.1 (a) is a longitudinal cross-sectional view of the boot 10 in 1st Embodiment of this invention, FIG.1 (b) is a front view of the boot 10 in the arrow Ib direction view of Fig.1 (a). .

  2 and 3 are partial cross-sectional views showing a state in which the boot 10 is attached to the connecting portion of the constant velocity joint CVJ. 2 and 3 show a state in which the axial centers O, P, and Q of the boot 10 and the transmission shafts 50 and 60 are coincident with each other. Further, the same parts as those of the constant velocity joint CVJ described in the background art are denoted by the same reference numerals, and the description thereof is omitted.

  The boot 10 is attached to a connecting portion of the constant velocity joint CVJ, and seals grease necessary for lubrication in the connecting portion and plays a role of preventing entry of foreign matters such as water and mud into the connecting portion. In the invention, it is configured to prevent the tip end portion of the transmission shaft 50 from falling out of the outer case 61.

  As shown in FIGS. 1 to 3, the boot 10 includes a large-diameter attachment portion 1 attached to the outer case 61, a small-diameter attachment portion 2 attached to the transmission shaft 50, and the large-diameter attachment portion 1 and the small-diameter attachment portion. 2 are mainly provided with a bellows part 3 that connects the two and a projecting part 4 positioned between the bellows part 3 and the large-diameter mounting part 1, and these parts are integrally formed of a thermoplastic elastomer resin material. Has been.

  As shown in FIGS. 1 to 3, the large-diameter mounting portion 1 has an outer peripheral surface formed in a circular shape concentric with a small-diameter mounting portion 2 described later, while an inner peripheral surface corresponds to the outer peripheral surface of the outer case 61. The outer case 61 is configured to be in close contact with the outer peripheral surface.

  That is, on the inner peripheral surface of the large-diameter mounting portion 1, three bulging portions 1a bulging inward in the radial direction are arranged at equal intervals in the circumferential direction (120 degree intervals). Each of the bulged portions 1 a is fitted into three recessed portions 61 b that are recessed in the outer peripheral surface of the outer case 61.

  In addition, the bulging part 1a of the large diameter attachment part 1 is provided with a plurality of lightening holes 1a1 opened at one end side (right side in FIG. 1A). Further, fastening grooves 1b and 2b serving as winding portions of the fastening band 80 are formed in the outer peripheral surfaces of the large diameter mounting portion 1 and the small diameter mounting portion 2 so as to be recessed over the entire circumference, and the inner peripheral surface has a sealing property. Two seal lips 1c, 2c are provided so as to project over the entire circumference.

  As shown in FIG. 1 to FIG. 3, the bellows portion 3 includes a valley portion and a mountain portion that are repeatedly and continuously formed in the direction of the axis O, and is configured to be expandable and contractable in the direction of the axis O. In addition, the taper is tapered so that the diameter decreases from the large diameter attachment portion 1 side toward the small diameter attachment portion 2 side. An internal space formed by the bellows portion 3 serves as a grease enclosure space.

  The overhanging portion 4 is a portion for preventing the tip end portion (the roller member 51 and the like) of the transmission shaft 50 from falling out of the outer case 61. As shown in FIGS. And the bellows part 3 and is formed to project from the inner peripheral surface side of the large-diameter attachment part 1 toward the transmission shaft 50.

  As will be described later, when the transmission shafts 50 and 60 of the constant velocity joint CVJ move relative to each other in a direction away from each other, the overhanging portion 4 contacts the roller member 51 of the transmission shaft 50 as shown in FIG. By making it possible, the relative movement of the transmission shafts 50 and 60 is restricted, and the transmission shaft 50 is prevented from falling out of the outer case 61.

  As shown in FIG. 1B, the overhanging direction tip 4a of the overhanging portion 4 is formed in a circular shape concentric and concentric with a virtual circle IS in contact with the three bulging portions 1a when viewed in the direction of the axis O. Yes. The virtual circle IS is a circle centered on the axis O, and, as shown in FIG. 1A, the smallest diameter surface excluding the seal lip 1c of the bulged portion 1a (that is, the base side of the seal lip 1c). The surface).

  Thus, by making the shape of the projecting direction tip 4a circular, the cooling rate at the time of molding can be made uniform over the entire projecting portion 4, and the occurrence of distortion can be suppressed, and the large-diameter mounting portion 1 and Since the difference in the cooling rate with the bellows portion 3 can be reduced, each of the portions 1, 3, and 4 can be accurately formed.

  Further, the shape of the projecting direction tip 4a is a circle having the same concentric diameter as the virtual circle IS when viewed in the direction of the axis O, as shown in FIG. 1A, the minimum diameter surface ( The protruding direction tip) and the protruding direction tip 4a of the protruding portion 4 can be flush with each other without a step, so that the generation of distortion on a part of this surface is suppressed, and the protruding portion 1a The inner peripheral surface can be accurately formed.

  Furthermore, the bottom part (bellows part) of the lightening hole 1a1 formed in the bulging part 1a is made by making the protruding part 4a of the bulging part 4 coincide with the minimum diameter surface (tip in the protruding direction) of the bulging part 1a. 3 side) can be prevented from becoming partially thick. As a result, at the time of molding, the thickness change can be reduced and the cooling rate of the entire bulged portion 1a can be made uniform, so that the bulged portion 1a can be molded with high accuracy.

  Here, the distance dimension L1 from the shaft core O to the front end 4a of the projecting portion 4 (see FIG. 1) is the distance dimension from the shaft core O (that is, the shaft cores P and Q) to the end face of the roller member 53. The distance dimension is set shorter than L2 (see FIG. 2 or 3) (L1 <L2).

  Thus, for example, when the transmission shafts 50 and 60 of the constant velocity joint CVJ are relatively moved away from each other in the state shown in FIG. 2, as shown in FIG. Since the movement of the transmission shaft 50 can be restricted by bringing the right side surface into contact with the side surface (left side surface in FIG. 3) of the roller member 53, the tip end portion (the roller member 53 and the like) of the transmission shaft 50 is inside the outer case 61. It is possible to avoid falling out of.

  In the present embodiment, as described above, since the overhanging portion 4 is overhanging to a position where the overhanging portion 4 can contact the roller member 53, the catching margin between the overhanging portion 4 and the roller member 53 is sufficiently large. Can be secured.

  That is, even when the roller member 52 gets over the overhanging portion 4 by the overhanging portion 4 being pushed and warped by the roller member 53, the tip end portion of the trunnion 51 is placed on the base side of the overhanging portion 4 (large Therefore, the tip end of the transmission shaft 50 can be reliably prevented from falling out of the outer case 61.

  Thus, if it is possible to prevent the tip end portion of the transmission shaft 50 from falling out of the outer case 61, as in the prior art (see FIG. 4), the assembly is transported while maintaining the posture of the assembly in order to avoid the dropout. There is no need to perform work or assembly work, and the degree of freedom of the posture of the assembled product at the time of transportation or assembly can be expanded, so that workability can be improved accordingly.

  Further, if the above-mentioned dropout can be suppressed, useless work of reinserting and connecting the dropped transmission shaft 50 into the outer case 61, or the fallen transmission shaft 50 damages the bellows portion 3 of the boot 10. Therefore, it is possible to reduce the man-hours and improve the yield as compared with the conventional product.

  In the present embodiment, as shown in FIG. 1A, the thickness dimension t1 of the overhanging portion 4 is configured to be thicker than the thickness dimension t2 of the bellows portion 3 (t2 <t1). Accordingly, sufficient rigidity can be given to the overhanging portion 4, so that the roller member 53 can be firmly received by the overhanging portion 4, and the tip end portion of the transmission shaft 50 can be more reliably removed from the outer case 61. Can be suppressed.

  Next, a second embodiment will be described with reference to FIG. In the first embodiment, the case where the gap between the first mountain of the bellows portion 3 (the mountain closest to the overhanging portion 4) and the overhanging portion 4 is a gap over the entire area has been described. However, the second embodiment Then, the connection part 4 b is provided between the first mountain of the bellows part 3 and the overhang part 4. In addition, the same code | symbol is attached | subjected to the part same as above-described 1st Embodiment, and the description is abbreviate | omitted.

  FIG. 4A is a front view of the boot 11 in the second embodiment, and FIG. 4B is a partial cross-sectional view of the boot 11 taken along the line IVb-IVb in FIG.

  As shown in FIG. 4, the boot 11 according to the second embodiment includes a plurality of connection portions 4 b that connect the first mountain of the bellows portion 3 and the side surface of the overhang portion 4 (left side surface in FIG. 1B). I have. As shown in FIG. 4A, these connecting portions 4b are arranged in a radial straight line with respect to the axis O while being distributed in the circumferential direction.

  In the present embodiment, a total of nine connection portions 4b, in which three are grouped, are arranged. The group of connection portions 4b are arranged at equal intervals in the circumferential direction (120 degree intervals), and in order to efficiently exhibit the reinforcing effect of the overhang portions 4 with a smaller number, the intermediate portions between the adjacent bulge portions 1a. Placed in position.

  In this way, by providing the plurality of connection portions 4b that connect the first mountain of the bellows portion 3 and the side surface of the overhang portion 4, the rigidity of the overhang portion 4 is increased, and the roller member 53 of the transmission shaft 50, etc. As a result, it is possible to reliably prevent the tip end portion of the transmission shaft 50 from falling out of the outer case 61.

  Further, since the rigidity required for the overhanging portion 4 itself can be reduced by the reinforcement effect by the connecting portion 4b, the thickness t2 of the overhanging portion 4 can be set to be thinner, As a result, the amount of the resin material used can be reduced, and the weight of the boot 11 as a whole and the material cost can be reduced at the same time.

  Furthermore, by disposing and arranging the connecting portions 4b in the circumferential direction, at the time of molding, the cooling rate of the connecting portions 4b can be increased, and the cooling rate in the vicinity of the connecting portions 4b can be made uniform. Generation | occurrence | production of the distortion of the overhang | projection part 4b can be suppressed, As a result, not only the overhang | projection part 4b but the bellows part 3 and the large diameter attaching part 1 can be shape | molded accurately.

  Here, as shown in FIG. 4B, the outer peripheral surface shape of the connecting portion 4 b is convex toward the axis O (that is, outward) in the vertical cross-sectional shape including the axis O of the boot 11. (Concave) arcuate shape. Thereby, stress concentration at the time of deformation can be eased and generation of distortion at the time of molding can be suppressed.

  In addition, it is preferable that the thickness dimension ta of the connection part 4b is set to be smaller than the thickness dimension t1 of the overhanging part 4 and thicker than the thickness dimension t2 of the bellows part 3. Thereby, at the time of shaping | molding, it is because it can suppress that a difference arises in the cooling rate between each site | part 3, 4, 4b, and generation | occurrence | production of distortion can be reduced.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. It can be easily guessed.

  For example, the numerical values (for example, the number of arrangements) given in the above embodiments are merely examples, and other numerical values can naturally be adopted.

  Further, in each of the above embodiments, the distance dimension L1 from the axis O to the protruding end 4a is set to be shorter than the distance dimension L2 from the axis O to the end surface of the roller member 53 (L1 < Although L2) has been described, it is not necessarily limited to this distance dimension, and other distance dimensions are naturally possible.

  For example, the distance dimension La (not shown) from the shaft core O to the front end 4a of the projecting portion 4 is greater than the distance dimension L2 from the shaft core O (that is, the shaft cores P and Q) to the end face of the roller member 53. And a distance dimension La from the axis O to the tip end of the trunnion 51 is set to a distance dimension L3 from the axis O to the tip end 4a of the extension 4 (see FIG. 2 or FIG. 3). ) May be set to a shorter distance dimension (L2 <La <L3).

  Thereby, since the overhang | projection part 4 can be made to contact | abut only to the front-end | tip part (projection part from the roller member 53) of the trunnion 51, the load action point which acts on the overhang | projection part 4 is made into the base side of the overhang | projection part 4. (Large diameter mounting portion 1 side) can be closer. Therefore, the leverage required for the overhanging portion 4 is reduced by the lever principle, and accordingly, the thickness t2 of the overhanging portion 4 can be set to be thinner. On the other hand, the amount of resin material used can be reduced to simultaneously reduce weight and material cost.

(A) is a longitudinal cross-sectional view of the boot in 1st Embodiment of this invention, (b) is a front view of the boot in the arrow Ib direction view of Fig.1 (a). It is a fragmentary sectional view which shows the state with which the boot was mounted | worn with the connection part of the constant velocity joint. It is a fragmentary sectional view which shows the state with which the boot was mounted | worn with the connection part of the constant velocity joint. (A) is a front view of the boot in 2nd Embodiment, (b) is the partial expanded sectional view of the boot in the IVb-IVb line | wire of Fig.4 (a). It is a figure which shows the conventional boot, and is a fragmentary sectional view which shows the state with which the boot was mounted | worn with the connection part of the constant velocity joint. It is sectional drawing of the boot in the VI-VI line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,11 Boot 1 Large diameter attaching part 1a Swelling part 2 Small diameter attaching part 3 Bellows part 4 Overhanging part 4a Overhanging direction front end 4b Connection part CVJ Constant velocity joint 50 Transmission shaft (the other transmission shaft)
51 trunnion (part of protruding part)
53 Roller member (part of protruding part)
60 Transmission shaft (One transmission shaft)
61 Outer case 61a Guide groove 61b Recess L1 Distance dimension from the shaft core to the tip of the overhanging portion L2 Distance dimension from the shaft core to the end surface of the roller member L3 Distance from the shaft core to the tip of the protruding portion in the protruding direction Dimensions, distance from shaft core to trunnion tip t1, overhang thickness t2, bellows thickness O shaft core (boot core)
P shaft core (axis of the other transmission shaft)
Q shaft core (shaft core of one transmission shaft)
IS virtual circle

Claims (7)

A plurality of guide grooves are recessed in the inner peripheral surface of the outer case of one transmission shaft, and a plurality of projecting portions projecting from the other transmission shaft are fitted in the plurality of guide grooves, respectively. A boot attached to a constant velocity joint configured to be expandable and contractable in the axial direction and capable of transmitting a rotational force, a large diameter attachment portion attached to an outer case of one transmission shaft of the constant velocity joint; A small-diameter attachment portion attached to the other transmission shaft of the constant velocity joint, the large-diameter attachment portion and the small-diameter attachment portion are connected to each other, and a valley portion and a mountain portion are repeatedly and continuously formed. In a boot comprising a bellows part that can expand and contract in the direction,
It is located between the large-diameter mounting portion and the bellows portion, and includes a projecting portion that is formed to project from the inner peripheral surface side of the large-diameter mounting portion toward the other transmission shaft,
The distance dimension from the shaft core to the projecting direction tip of the projecting part is set to a distance dimension shorter than the distance dimension from the shaft core to the projecting direction tip of the projecting part, and the one transmission shaft and the one A boot characterized in that the projecting portion comes into contact with the projecting portion when the other transmission shaft is relatively moved in a direction away from each other.   The boot according to claim 1, wherein the large-diameter attachment portion, the overhang portion, the bellows portion, and the small-diameter attachment portion are integrally formed from a resin material. A plurality of recesses are provided in the outer circumferential surface of the outer case in a distributed manner in the circumferential direction.
The large-diameter mounting portion includes a plurality of bulging portions protruding from an inner peripheral surface of the large-diameter mounting portion, and the plurality of bulging portions are configured to be externally fitted to the plurality of concave portions, respectively.
The tip of the overhanging direction of the overhanging part is configured in a circular shape that is concentric and concentric with a virtual circle that contacts each of the plurality of bulging parts in the axial direction view. boots.   The boot according to any one of claims 1 to 3, wherein a thickness dimension of the overhang portion is configured to be thicker than a thickness dimension of the bellows portion. The projecting portion includes a trunnion projecting in a direction perpendicular to the axis from the other transmission shaft, and an annular roller member that is slidably fitted to the trunnion, and a tip end portion of the trunnion is the roller Configured to protrude from the end face of the member,
The distance dimension from the shaft core to the tip of the projecting part in the projecting direction is set to a distance dimension longer than the distance dimension from the shaft core to the end surface of the roller member, and the projecting part from the shaft core 5. The boot according to claim 1, wherein a distance dimension from the tip end in the projecting direction is set to a distance dimension shorter than a distance dimension from the shaft core to the tip end portion of the trunnion. . The projecting portion includes a trunnion projecting in a direction perpendicular to the axis from the other transmission shaft, and an annular roller member that is slidably fitted to the trunnion, and a tip end portion of the trunnion is the roller Configured to protrude from the end face of the member,
The distance dimension from the said shaft core to the front-end | tip of the overhang | projection part of the said overhang | projection part is set to the distance dimension shorter than the distance dimension from the said shaft core to the said end surface of the said roller member. 4. The boot according to any one of 4.   2. The apparatus according to claim 1, further comprising a plurality of connection portions that connect the first peak of the bellows portion and the overhang portion, and the plurality of connection portions are distributed in the circumferential direction. The boot according to any one of 6.

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