JP2011140967A - Drive shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily reduce the number of part items and assembling man-hours, and to reduce a dimension in the axial direction of an outside joint member. <P>SOLUTION: This drive shaft includes an intermediate shaft 10 and a pair of sliding type constant velocity universal joints 20 and 40 composed of cup-shaped outside joint members 23 and 43 having an opening part on one end and inside joint members 26 and 46 connected to both ends of the intermediate shaft 10 so that torque can be transmitted and transmitting the torque while allowing angular displacement and displacement in the axial direction via balls 27 and 47 between the outside joint members 23 and 43 and the inside joint members, and is provided by respectively installing an end part of cylindrical boots 30 and 50 for blocking up an opening part of the outside joint members 23 and 43 in the opening part of the outside joint members 23 and 43 and the intermediate shaft 10. The boots 30 and 50 have a reaction characteristic of 0.5-3.0 kN/mm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a drive shaft that is used in a power transmission system of an automobile or various industrial machines and has a pair of sliding constant velocity universal joints connected to both ends of an intermediate shaft.

  For example, there are two types of constant velocity universal joints that are used as means for transmitting a rotational force from an automobile engine to wheels at a constant velocity: a fixed constant velocity universal joint and a sliding constant velocity universal joint. Both of these constant velocity universal joints have a structure in which two shafts on the driving side and the driven side are connected so that rotational torque can be transmitted at a constant speed even if the two shafts have an operating angle.

  A drive shaft that transmits power from an automobile engine to a driving wheel needs to cope with an angular displacement and an axial displacement caused by a change in a relative positional relationship between the engine and the wheel. Side) and a fixed type constant velocity universal joint on the wheel side (outboard side), and a structure in which both constant velocity universal joints are connected by an intermediate shaft.

  Further, in the case of a rear drive shaft of an automobile, a large angular displacement is not required on the wheel side (outboard side), so a sliding type constant velocity universal joint is used on both the engine side and the wheel side. There is also a structure in which the sliding type constant velocity universal joints are connected by an intermediate shaft.

  In the rear drive shaft in which a pair of sliding constant velocity universal joints are connected to both ends of the intermediate shaft, the sliding constant velocity universal joints located on both sides of the intermediate shaft must allow axial displacement. Therefore, the intermediate shaft can move in the axial direction between the sliding type constant velocity universal joints attached to the engine side and the wheel side, and the axial position is not determined. Therefore, some drive shafts of this type have a structure that automatically aligns the intermediate shaft so that the intermediate shaft can be forcibly positioned in the axial direction (see, for example, Patent Document 1).

  The drive shaft disclosed in Patent Document 1 has a structure in which tripod type constant velocity universal joints 120 and 140 are connected to both ends of the intermediate shaft 110 as shown in FIG.

  The basic configurations of both constant velocity universal joints 120 and 140 are the same, and are formed into a cup shape having an opening at one end, and three track grooves 121 and 141 extending in the axial direction are formed on the inner peripheral surface. Tripod members 125 and 145 having outer joint members 123 and 143 formed with roller guide surfaces 122 and 142 opposed to each other on inner walls of the track grooves 121 and 141 and three leg shafts 124 and 144 projecting in the radial direction. And are rotatably supported by the leg shafts 124 and 144 of the tripod members 125 and 145 and are rotatably inserted into the track grooves 121 and 141 of the outer joint members 123 and 143 along the roller guide surfaces 122 and 142. The main parts are composed of the rollers 126 and 146 guided in this manner.

  These constant velocity universal joints 120 and 140 have a structure in which inner parts including rollers 126 and 146 and tripod members 125 and 145 are accommodated in outer joint members 123 and 143 so as to be axially slidable. These parts are connected to the shaft holes of the tripod members 125 and 145 so that torque can be transmitted by spline fitting. Further, in order to prevent leakage of a lubricant such as grease enclosed in the joint and to prevent foreign matter from entering from the outside of the joint, cylindrical boots 127 and 147 are provided between the outer joint members 123 and 143 and the intermediate shaft 110. The structure is equipped with.

  In the constant velocity universal joint 120 on the outboard side (the left side in the figure), a compression coil spring 128 is inserted into a recess formed in the bottom of the outer joint member 123, and a concave spherical member 129 is attached to the tip thereof, and a tripod member A convex spherical member 130 is attached to the end of the intermediate shaft 110 protruding from 125, and the concave spherical member 129 and the convex spherical member 130 are abutted. On the other hand, in the constant velocity universal joint 140 on the inboard side (the right side in the figure), the concave spherical member 149 is mounted on the bottom of the outer joint member 143 and at the end of the intermediate shaft 110 protruding from the tripod member 145. A convex spherical member 150 is mounted, and the concave spherical member 149 and the convex spherical member 150 are abutted against each other.

  By providing the above structure, in the drive shaft of Patent Document 1, the intermediate shaft 110 is forcibly applied by causing the elastic force of the compression coil spring 128 to act on the intermediate shaft 110 from the outboard side to the inboard side. Self-aligning so that positioning is possible.

JP-A-2005-172142

  Incidentally, in the conventional drive shaft disclosed in Patent Document 1 described above, in the constant velocity universal joint 120 on the outboard side, a compression coil spring 128 is incorporated inside the outer joint member 123 and a concave spherical member 129 is provided at the tip thereof. And a convex spherical member 130 is attached to the end of the intermediate shaft 110. In the constant velocity universal joint 140 on the inboard side, a concave spherical member 149 is attached to the inside of the outer joint member 143. In addition, a convex spherical member 150 is attached to the end of the intermediate shaft 110.

  Therefore, in the conventional drive shaft, since separate parts of the compression coil spring 128, the concave spherical members 129 and 149, and the convex spherical members 130 and 150 are required, the drive shaft is increased due to an increase in the number of parts and an increase in assembly man-hours. Will increase the cost.

  Further, the compression coil spring 128, the concave spherical members 129 and 149, and the convex spherical members 130 and 150 are combined into the outer joint members 123 and 143 and the intermediate shaft 110, and the compression coil spring 128 and the concave spherical member are formed. A space for accommodating the separate members 129 and 149 and the convex spherical members 130 and 150 is also required, and the axial dimensions of the outer joint members 123 and 143 are increased, making it difficult to make the drive shaft compact.

  Therefore, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is a drive that can easily reduce the number of parts and assembly man-hours and the axial dimension of the outer joint member. To provide a shaft.

  As technical means for achieving the above-mentioned object, the present invention comprises an intermediate shaft, a cup-shaped outer joint member having an opening at one end, and both ends of the intermediate shaft connected to each other so as to be able to transmit torque. A pair of sliding type constant velocity universal joints composed of an inner joint member that transmits torque while allowing angular displacement and axial displacement through a torque transmission member between the joint member and an opening of the outer joint member A drive shaft in which ends of a cylindrical boot that closes the shaft are attached to the opening of the outer joint member and the intermediate shaft, respectively, and the boot has a reaction force characteristic of 0.5 to 3.0 kN / mm It is characterized by. Here, the “reaction force characteristic” means the rigidity force of the boot per unit length acting in the opposite direction with respect to the axial force generated in the constant velocity universal joint by applying the rotational torque.

  The boot may be made of rubber or resin. Further, the pair of sliding type constant velocity universal joints may be connected to both ends of the intermediate shaft in either the same phase or different phases. Here, “phase” means the circumferential position of the torque transmitting member disposed between the outer joint member and the inner joint member.

  In the present invention, by using a boot having a reaction force characteristic of 0.5 to 3.0 kN / mm, even if the rotational torque is loaded, the intermediate shaft is forced by the centering action by the boot. Thus, it is possible to ensure automatic alignment for positioning in the initial state. By realizing such automatic alignment with the boot, the separate parts of the compression coil spring, the concave spherical member and the convex spherical member as in the prior art are no longer required, so the number of parts and the number of assembly steps can be reduced. . In addition, since the space for accommodating the compression coil spring, the concave spherical member, and the separate components of the convex spherical member is not required, the axial dimension of the outer joint member can be easily reduced.

  If the reaction force characteristic is smaller than 0.5 kN / mm, it is difficult to exert the alignment effect by the boot, and it is difficult to position the intermediate shaft in the initial state. Also, if the reaction force characteristic is larger than 3.0 kN / mm, it is possible to exert the centering effect by the boot, but the rigidity of the boot becomes too high. Therefore, the operability of the constant velocity universal joint or the durability of the boot itself is lowered.

  Each of the pair of sliding constant velocity universal joints in the present invention is desirably of the same specification. Further, it is desirable that the boots mounted on the pair of sliding type constant velocity universal joints have the same specifications. Here, the “same specifications” means constant velocity universal joints having the same size and structure, or boots having the same size and material. In this way, if constant velocity universal joints or boots of the same specification are used, the axial force generated in the constant velocity universal joint or the rigid force of the boots by the application of rotational torque is the same in each constant velocity universal joint or boot. Therefore, the amount of axial movement of the intermediate shaft can be minimized, and automatic alignment that forcibly positions the intermediate shaft in the initial state by the alignment operation by the boot can be realized more reliably. it can.

  In the present invention, the outer joint member is formed with a plurality of linear track grooves extending in the axial direction on the cylindrical inner peripheral surface, and the inner joint member is formed on the spherical outer peripheral surface in pairs with the track grooves of the outer joint member. And the torque transmitting member is held by a cage disposed between the cylindrical inner peripheral surface of the outer joint member and the spherical outer peripheral surface of the inner joint member. A structure that is a ball interposed between the track groove of the inner joint member and the track groove of the inner joint member is desirable. The present invention can be applied to a constant velocity universal joint having such a structure, that is, a double offset type constant velocity universal joint. The number of balls is preferably six, but the number is arbitrary.

  In the outer joint member of the present invention, three track grooves extending in the axial direction are formed on the inner peripheral surface, and roller guide surfaces facing each other are formed on the inner side wall of each track groove. It has three leg shafts projecting in the radial direction, and the torque transmission member is rotatably supported by the leg shaft and is inserted into the track groove of the outer joint member so as to roll along the roller guide surface. The structure is desirable. The present invention is applicable to a constant velocity universal joint having such a structure, that is, a tripod type constant velocity universal joint.

  According to the present invention, by using a boot having a reaction force characteristic of 0.5 to 3.0 kN / mm, even if the rotational torque is loaded, the intermediate shaft can be moved by the centering action by the boot. It is possible to ensure automatic alignment for forcibly positioning to the initial state. By realizing such automatic alignment with the boot, the separate parts of the compression coil spring, the concave spherical member and the convex spherical member as in the prior art are no longer required, so the number of parts and the number of assembly steps can be reduced. . In addition, since the space for accommodating the compression coil spring, the concave spherical member, and the separate components of the convex spherical member is not required, the axial dimension of the outer joint member can be easily reduced.

  In this way, the cost of the constant velocity universal joint can be easily reduced by reducing the number of parts and the number of assembly steps, and the axial dimension of the outer joint member can be reduced to make the constant velocity universal joint more compact and inexpensive. A small drive shaft can be provided.

1 is a longitudinal sectional view showing an overall configuration of a drive shaft in an embodiment of the present invention. When a pair of constant velocity universal joints are connected in the same phase, (a) is a cross-sectional view showing the constant velocity universal joint on the outboard side, and (b) is a cross sectional view showing the constant velocity universal joint on the inboard side. It is. When a pair of constant velocity universal joints are connected at different phases, (a) is a cross-sectional view showing the constant velocity universal joint on the outboard side, and (b) is a cross sectional view showing the constant velocity universal joint on the inboard side. It is. It is a table | surface which shows the test conditions and test result (in the case of no boots) which the present applicant performed. It is a wave form diagram which shows the test result (when there is boots) which the present applicant conducted. It is a longitudinal cross-sectional view which shows the conventional drive shaft.

  Embodiments of the drive shaft according to the present invention will be described in detail below. In the following embodiments, the engine side (inboard side) and the wheel side (outboard side) of the automobile are each equipped with a sliding type constant velocity universal joint, and both the constant velocity universal joints are connected by an intermediate shaft. The rear drive shaft provided is exemplified, and a case where a double offset type constant velocity universal joint is applied as one of the sliding type constant velocity universal joints is exemplified.

  The drive shaft in the embodiment shown in FIGS. 1 and 2A and 2B has a structure in which double offset constant velocity universal joints 20 and 40 are connected to both ends of the intermediate shaft 10. The constant velocity universal joint 20 on the outboard side (left side in FIG. 1) and the constant velocity universal joint 40 on the inboard side (right side in FIG. 1) have the same basic configuration. In FIG. 1, a part of the intermediate shaft 10 is omitted. 2A is a cross-sectional view of the constant velocity universal joint 20 on the outboard side, and FIG. 2B is a cross-sectional view of the constant velocity universal joint 40 on the inboard side.

  Both constant velocity universal joints 20 and 40 have a cup shape having an opening at one end, and a plurality of linear track grooves 21 and 41 parallel to the axis are circumferentially equidistant from the cylindrical inner peripheral surfaces 22 and 42. The outer joint members 23, 43 formed in the above-described manner and a plurality of linear track grooves 24, 44 parallel to the axis corresponding to the track grooves 21, 41 of the outer joint members 23, 43 are spherical outer peripheral surfaces 25, 45. A plurality of inner joint members 26 and 46 formed between the outer joint members 23 and 43 and the track grooves 21 and 41 of the outer joint members 23 and the track grooves 24 and 44 of the inner joint members 26 and 46. It is arranged between the balls 27 and 47, which are torque transmission members, the inner peripheral surfaces 22 and 42 of the outer joint members 23 and 43, and the outer peripheral surfaces 25 and 45 of the inner joint members 26 and 46, and at equal intervals in the circumferential direction. Pockets 28 and 48 formed A cage 29, 49 for holding the accommodated balls 27 and 47 are the major components. In this embodiment, six balls 27 and 47 are illustrated as shown in FIGS. 2 (a) and 2 (b). However, the balls 27 and 47 are any of 3, 5, or 8 in addition. The number is arbitrary.

  Both of the constant velocity universal joints 20 and 40 have a structure in which internal parts including inner joint members 26 and 46, balls 27 and 47 and cages 29 and 49 are accommodated in the outer joint members 23 and 43 so as to be slidable in the axial direction. It has. Further, the end of the intermediate shaft 10 is connected to the shaft holes of the inner joint members 26 and 46 by spline fitting. Further, in order to prevent leakage of a lubricant such as grease enclosed in the joint and to prevent foreign matter from entering from the outside of the joint, the cylindrical boots 30 and 50 are interposed between the outer joint members 23 and 43 and the intermediate shaft 10. It has a structure equipped with.

  As described above, by encapsulating the lubricant in the inner space of the outer joint members 23 and 43 and the boots 30 and 50, the intermediate shaft 10 rotates while taking an operating angle with respect to the outer joint members 23 and 43. The sliding part inside the joint, that is, the sliding part constituted by the outer joint members 23 and 43, the inner joint members 26 and 46, the balls 27 and 47, and the cages 29 and 49 is ensured. Yes.

  The boots 30 and 50 include large-diameter end portions 32 and 52 fastened and fixed to the outer peripheral surfaces of the openings of the outer joint members 23 and 43 by boot bands 31 and 51, and the intermediate shaft 10 extending from the inner joint members 26 and 46. The small-diameter end portions 34 and 54 fastened and fixed to the outer peripheral surface by the boot bands 33 and 53, the large-diameter end portions 32 and 52, and the small-diameter end portions 34 and 54 are connected, and the large-diameter end portions 32 and 52 are connected to the small-diameter end. It is comprised with the elastic bellows parts 35 and 55 which were diameter-reduced toward the parts 34 and 54. As shown in FIG.

  As these boots 30 and 50, natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, chloroprene rubber, butyl rubber, nitrile rubber, hydrogenated nitrile rubber, ethylene propylene rubber, ethylene acrylic rubber, chlorinated polyethylene, chlorosulfonated polyethylene Made of rubber such as silicone rubber, urethane rubber, fluoro rubber, chlorosulfone rubber, etc., or ester elastomer, urethane elastomer, olefin elastomer, urethane elastomer, styrene elastomer, amide elastomer, vinyl chloride elastomer Resins made of various known elastomers such as the above can be used.

  The boots 30 and 50 attached to both constant velocity universal joints 20 and 40 have reaction force characteristics of 0.5 to 3.0 kN / mm. Here, the reaction force characteristic means the rigidity force of the boots 30 and 50 per unit length acting in the opposite direction with respect to the axial force generated in the constant velocity universal joints 20 and 40 by applying the rotational torque. .

  By using the boots 30 and 50 having reaction force characteristics of 0.5 to 3.0 kN / mm, the intermediate shaft 10 can be adjusted by the centering action by the boots 30 and 50 even when the rotational torque is applied. It is possible to secure automatic alignment for forcibly positioning the lens in the initial state. By realizing such automatic alignment with the boots 30 and 50, separate parts such as the conventional compression coil spring 128, concave spherical members 129 and 149 and convex spherical members 130 and 150 (see FIG. 6) are obtained. Since it becomes unnecessary, the number of parts and the number of assembly steps can be reduced. Further, since the space for accommodating the separate parts of the compression coil spring 128, the concave spherical members 129 and 149 and the convex spherical members 130 and 150 (see FIG. 6) is not required, the axial direction of the outer joint members 23 and 43 is eliminated. The size can be easily reduced.

  If this reaction force characteristic is smaller than 0.5 kN / mm, it is difficult to exert the alignment action by the boots 30 and 50, and it becomes difficult to position the intermediate shaft 10 in the initial state. 10 is shifted to one of the constant velocity universal joints 20 and 40 side. Further, if the reaction force characteristic is larger than 3.0 kN / mm, it is possible to exert the alignment action by the boots 30 and 50, but the rigidity of the boots 30 and 50 becomes too high. The handling property at the time of vehicle assembly, the operability of the constant velocity universal joints 20 and 40, or the durability of the boot itself will be lowered.

  The present applicant conducted a test on the drive shaft (see FIG. 1) in which the double offset constant velocity universal joints 20 and 40 described above are connected to both ends of the intermediate shaft 10 based on the following conditions. In order to eliminate the influence of the weights of the left and right constant velocity universal joints 20 and 40 shown in the figure, a mounting angle of 10 ° was set in the horizontal direction, and rotational torque was applied to the constant velocity universal joints 20 and 40 at a rotation speed of 100 rpm. In addition, the phase of the constant velocity universal joints 20 and 40 shown in the figure, the rotation direction, the driving direction, and the movement of the intermediate shaft 10 as a test result are as shown in the table of FIG. FIG. 4 shows a case where the boots 30 and 50 are not attached.

  As shown in FIG. 4, among the drive shafts of conditions A to H, the conditions A to D are the same phase, and the conditions E to H are the opposite phase. Here, the same phase means the left and right constant velocity universal joint 20 and the constant velocity universal joint 40 shown in FIG. 1 and the circumferential positions of the balls 27 and 47 as shown in FIGS. Means the same. As shown in FIGS. 3A and 3B, the reverse phase means that the circumferential positions of the balls 27 and 47 are shifted by, for example, 30 ° between the constant velocity universal joint 20 and the constant velocity universal joint 40. To do. In addition, the conditions C, D, G, and H are normal rotations, and the conditions A, B, E, and F are reverse rotations. With respect to this rotation direction, the arrow direction in FIG. 1 is the forward rotation “+”, and the opposite direction is the reverse rotation “−”. Furthermore, with respect to the driving direction, the left and right constant velocity universal joints 20 and the constant velocity universal joint 40 “drive” the side that applies the rotational torque, and “driven” the side that follows the application of the rotational torque. It was.

  As a result of the test based on these conditions, as shown by “movement of the intermediate shaft” in FIG. 4, the intermediate shaft 10 is connected to the driven-side constant velocity universal joints 20, 40 from the driven-side constant velocity universal joints 20, 40 regardless of the rotation direction and phase. It turned out that it moved toward the constant velocity universal joints 20 and 40. In the driven constant velocity universal joints 20, 40, the internal parts continue to move until they abut against the bottom surfaces of the outer joint members 23, 43, and then the internal parts are in contact with the bottom surfaces of the outer joint members 23, 43. Continue to rotate.

  On the other hand, the boots 30 and 50 having a reaction force characteristic of 0.5 to 3.0 kN / mm are applied to the constant velocity universal joints 20 and 40 (when the boots 30 and 50 are not mounted) of the drive shafts in the above conditions A to H. The drive shafts under conditions A to H with the boots 30 and 50 attached were tested under the same conditions as when the boots 30 and 50 were not attached.

  As a result, test results as shown in FIG. 5 were obtained for all drive shafts under conditions A to H. That is, the intermediate shaft 10 starts to move from the constant velocity universal joints 20 and 40 on the driving side toward the constant velocity universal joints 20 and 40 on the driven side, but immediately moves in the opposite direction and is several mm. After moving from the constant velocity universal joints 20 and 40 on the driving side to the constant velocity universal joints 20 and 40 on the driven side, it moves in the opposite direction.

  In this way, with the amplitude W of several millimeters around the initial position, the movement from the constant velocity universal joints 20 and 40 on the driving side to the constant velocity universal joints 20 and 40 on the driven side and the constant velocity universal on the driven side are possible. It has been found that the movement from the joints 20 and 40 to the constant velocity universal joints 20 and 40 on the driving side is repeated. In addition, although this test was performed for 10 minutes from the start of operation, the internal components of the constant velocity universal joints 20 and 40 did not hit the bottom surfaces of the outer joint members 23 and 43.

  From the above test results, when the boots 30 and 50 are not mounted, the intermediate shaft 10 is driven from the drive-side constant velocity universal joints 20 and 40 by the axial force generated in the constant velocity universal joints 20 and 40. It moves toward the constant velocity universal joints 20 and 40 on the side. On the other hand, when the boots 30 and 50 having a reaction force characteristic of 0.5 to 3.0 kN / mm are mounted, the constant velocity universal joint 20 on the drive side with an amplitude W of several millimeters around the initial position. By repeating the movement from 40 to the driven constant velocity universal joints 20 and 40 and the movement from the driven side constant velocity universal joints 20 and 40 to the driving side constant velocity universal joints 20 and 40, the boot Automatic alignment by 30, 50 can be realized.

  The left and right constant velocity universal joints 20 and 40 or the boots 30 and 50 have the same specifications. Here, the “same specification” means constant velocity universal joints 20 and 40 having the same size and structure, or boots 30 and 50 having the same size and material.

  As described above, by using the constant velocity universal joints 20 and 40 or the boots 30 and 50 having the same specifications, the axial force generated in the constant velocity universal joints 20 and 40 or the rigidity force of the boots 30 and 50 due to the application of rotational torque. Is the same for each constant velocity universal joint 20, 40 or boot 30, 50. Therefore, automatic alignment for forcibly positioning the intermediate shaft 10 in the initial state by the alignment operation by the boot 30, 50 is further enhanced. It can be realized reliably. Further, the amount of axial movement of the intermediate shaft 10 can be minimized, and the axial length of the outer joint members 23 and 43 can be minimized, so that the axial dimension of the drive shaft can be shortened. Compact size can be easily achieved.

  In the above embodiment, the case where the double offset type constant velocity universal joint is applied as one of the sliding type constant velocity universal joints has been described. However, the present invention is not limited to this, and other sliding type etc. It is also possible to apply a tripod type constant velocity universal joint as the speed universal joint.

  Although not shown, this tripod type constant velocity universal joint has three track grooves extending in the axial direction on the inner peripheral surface and an outer joint in which roller guide surfaces facing each other are formed on the inner wall of each track groove. A member, a tripod member which is an inner joint member having three leg shafts projecting in the radial direction, and a roller guide which is rotatably supported by the leg shaft and is rotatably inserted into a track groove of the outer joint member. It is comprised with the roller which is a torque transmission member guided along a surface (refer FIG. 6).

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

10 Intermediate shaft 20, 40 Constant velocity universal joint 21, 41 Track groove 22, 42 Cylindrical inner peripheral surface 23, 43 Outer joint member 24, 44 Track groove 25, 45 Spherical outer peripheral surface 26, 46 Inner joint member 27, 47 Torque transmission member (ball)
29,49 Cage 30,50 Boots

Claims (10)

  An intermediate shaft, a cup-shaped outer joint member having an opening at one end, and both ends of the intermediate shaft are connected so as to be able to transmit torque, and are angularly displaced between the outer joint member and the outer joint member via a torque transmission member. A pair of sliding type constant velocity universal joints configured to transmit torque while allowing axial displacement, and an end portion of a cylindrical boot that closes an opening of the outer joint member is connected to the outer joint A drive shaft mounted on each of the opening of the member and the intermediate shaft, wherein the boot has a reaction force characteristic of 0.5 to 3.0 kN / mm.   The drive shaft according to claim 1, wherein the boot is made of rubber.   The drive shaft according to claim 1, wherein the boot is made of resin.   The drive shaft according to any one of claims 1 to 3, wherein each of the pair of sliding constant velocity universal joints has the same specification.   5. The drive shaft according to claim 1, wherein the boots mounted on the pair of sliding constant velocity universal joints have the same specifications.   The drive shaft according to any one of claims 1 to 5, wherein the pair of sliding constant velocity universal joints are coupled to both ends of the intermediate shaft in the same phase.   The drive shaft according to any one of claims 1 to 5, wherein the pair of sliding constant velocity universal joints are connected to both ends of the intermediate shaft at different phases.   The outer joint member has a plurality of linear track grooves extending in the axial direction on a cylindrical inner peripheral surface, and the inner joint member forms a plurality of pairs on the spherical outer peripheral surface in pairs with the track grooves of the outer joint member. A straight track groove is formed, and the torque transmission member is held by a cage disposed between a cylindrical inner peripheral surface of the outer joint member and a spherical outer peripheral surface of the inner joint member, and the outer joint The drive shaft according to any one of claims 1 to 7, wherein the drive shaft is a ball interposed between a track groove of a member and a track groove of the inner joint member.   The drive shaft according to claim 8, wherein the number of the balls is six.   In the outer joint member, three track grooves extending in the axial direction are formed on the inner peripheral surface, and roller guide surfaces facing each other are formed on the inner wall of each track groove, and the inner joint member is formed in the radial direction. The torque transmission member is rotatably supported by the leg shaft and is rotatably inserted in the track groove of the outer joint member and guided along the roller guide surface. The drive shaft according to any one of claims 1 to 7.

Images