JP4324405B2 - Impact drag reduction structure for vehicle propeller shaft - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an impact drag reduction structure for a propeller shaft for a vehicle that transmits driving force of an engine to driving wheels.
[0002]
[Prior art]
In general, a power transmission system for a four-wheel drive vehicle (4WD) or a front engine rear drive (FR) vehicle has a front end portion of a propeller shaft disposed in the front-rear direction with respect to the vehicle body. In addition to being connected to the output shaft, the rear end portion is connected to the drive shaft of the rear wheel, which is the drive wheel, via a differential device.
[0003]
Since this propeller shaft extends in the front-rear direction with respect to the vehicle body, for example, the propeller shaft is stretched against deformation of the vehicle body due to an impact load acting from the front of the vehicle during a vehicle collision. It affects the absorption of impact load due to deformation.
[0004]
Therefore, there are various impact drag reduction structures that protect the occupant by absorbing the impact load from the front side of the vehicle by contracting the propeller shaft arranged extending in the longitudinal direction of the vehicle body by the axial load. Proposed.
[0005]
  For example, the figure9Figure 4 schematically shows the power transmission system and10To the figure9As shown in the enlarged sectional view of part C, a front propeller shaft 101 and a rear propeller shaft 100 connected to a rear end portion of the front propeller shaft 101 via a universal joint 110 are formed. A front end portion of the front propeller shaft 101 is connected to an output shaft of a power unit 113 including an engine and a transmission via a universal joint 112, and a rear end portion of the rear propeller shaft 105 is a driving wheel via a universal joint 114. It connects with the differential apparatus 116 for rear wheels. Furthermore, the front propeller shaft 101 is provided with cone-shaped coupling bodies 104a and 104b that can be deformed by a predetermined load or more at the rear end of the long front shaft main body 102 and the front end of the rear shaft main body 103. Both the coupling bodies 104a and 104b are opposed to each other and end portions are coupled to each other.
[0006]
In a vehicle to which the propeller shaft 100 configured in this way is applied, when the power unit 113 moves toward the rear of the vehicle body due to a collision or the like and a collision load acts on the front propeller shaft 101, the front shaft of the front propeller shaft 101 It is known that the coupling bodies 104a and 104b disposed between the main body 102 and the rear shaft body 103 buckle and the front propeller shaft 101 contracts, and the impact loads are absorbed by the buckling of the coupling bodies 104a and 104b. (For example, refer to Patent Document 1).
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-309146 (paragraph number 0013, FIGS. 1 and 2)
[0008]
[Problems to be solved by the invention]
According to the propeller shaft 100 described in Patent Document 1, the coupling bodies 104a and 104b are buckled by the impact load acting from the front of the vehicle body at the time of a vehicle collision, and the propeller shaft 100 contracts, so that the impact load due to deformation of the vehicle body is reduced. Absorption is possible.
[0009]
However, a relatively large load is required to buckle the cone-like coupling bodies 104a and 104b, and there is a concern that smooth impact load absorption due to sufficient vehicle body deformation cannot be achieved.
[0010]
On the other hand, the propeller shaft 100 mainly transmits rotational torque, but when the coupling bodies 104a and 104b are disposed between the front shaft body 102 and the rear shaft body 103 for contracting the propeller shaft 100, Since an axial load acts when the vehicle starts, suddenly brakes, or bumps / rebounds, the rotational torque and the axial load repeatedly act on the coupling bodies 104a and 104b during normal running, and are easily damaged by fatigue. Is likely to be. For this reason, it is conceivable that the strengths of the coupling bodies 104a and 104b are set to be high in advance, but the impact resistance of the coupling bodies 104a and 104b is increased, so that smooth impact load absorption due to deformation of the vehicle body is hindered. Further, since it is difficult to predict a change in the drag characteristics due to the coupling bodies 104a and 104b with time and it is impossible to know when the impact load due to a collision or the like is applied, the propeller when the impact load is actually applied is not possible. It is extremely difficult to predict the behavior characteristics of the shaft. Furthermore, since the structure differs greatly from the conventional propeller shaft due to the arrangement of the coupling bodies 104a and 104b, the behavior characteristics are greatly different from the conventional propeller shaft, and it is difficult to predict the behavior characteristics, making it difficult to tune the behavior characteristics and reliable. This is a factor that causes a decline in sex.
[0011]
In addition, the hollow cylindrical shaft tube that forms the propeller shaft may be partially expanded or contracted to enable shrinkage due to impact load. Then, since the rapidly changing cross-sectional shape is difficult and changes slowly, there is a concern that the reduction of impact resistance cannot be achieved.
[0012]
Therefore, the object of the present invention made in view of such points is excellent in reliability that can presume the behavior characteristics of the propeller shaft when impact load is applied with very little change with time and can ensure stable reduction of impact resistance. Another object is to provide a structure for reducing the impact resistance of a propeller shaft for a vehicle.
[0013]
[Means for Solving the Problems]
  The invention of the structure for reducing the drag force of a propeller shaft for a vehicle according to claim 1 that achieves the above object extends along the longitudinal direction of the vehicle body, and has a front propeller shaft and a rear end portion of the front propeller shaft via a joint. In the structure for reducing the impact resistance of the propeller shaft including the rear propeller shaft to which the front end portion is coupled, the joint is integrally formed continuously from the base portion and the rear in the axial direction. An extension portion coupled to the front end portion of the propeller shaft, and the extension portion has a small diameter range formed substantially the same diameter as the base portion, and a large diameter range having a diameter larger than the small diameter range. A cylindrical outer case formed continuously through a stepped portion;
  A base portion is coupled to a rear end portion of the front propeller shaft, and a front end shaft portion is disposed between the joint shaft inserted into the outer case, the base portion, and the front end shaft portion. A torque transmitting portion that engages the case and the joint shaft movably in the axial direction and transmits rotational torque, and the outer case by the axial movement of the front propeller shaft caused by an impact load from the front of the vehicle body And a load transmission means for restricting the amount of the joint shaft entering the outer case, and transmitting the impact load to the outer case, and the outer case of the joint shaft by the load transmission means. When the amount of entry into the inside is restricted, the torque transmission part isAbutIt is characterized by that.
[0014]
According to the first aspect of the present invention, the rotational torque from the power unit in normal traveling is smoothly transmitted through the front propeller shaft, the joint and the rear propeller shaft, and the vehicle is started by the joint or suddenly braked. The relative movement in the axial direction of the front propeller shaft and the rear propeller shaft is allowed at the time of bumping or rebounding, and vibration and noise of the vehicle body are reduced, so that excellent riding comfort and comfort can be ensured.
[0015]
On the other hand, when an impact load is applied from the front of the vehicle body, the joint shaft smoothly enters the outer case with an extremely small load by the torque transmission portion as the front propeller shaft moves backward, and as the front propeller shaft moves backward. The propeller shaft contracts. Due to this contraction, the propeller shaft is prevented from being stretched to facilitate the deformation of the vehicle body, and the impact can be reduced by absorbing the impact load due to the deformation of the vehicle body. Thereafter, when the load transmitting means comes into contact with the outer case, the impact load is transmitted to the outer case, and the small diameter range of the extension portion and the continuous portion of the step portion and the continuous portion of the step portion and the large diameter range are buckled and deformed. Furthermore, the impact load is absorbed and the impact is reduced.
[0016]
  In addition, there is no change over time in the characteristics of the joint, front propeller shaft, and rear propeller shaft, and it is extremely easy to assume the behavior characteristics of the propeller shaft based on experiments or simulations in advance when an impact load is actually applied. It is easy to tune behavior characteristics.In addition, when the impact load is applied from the front of the vehicle body, interference between the joint shaft and the extension portion is avoided by forming a large diameter range by breaking the step portion following the small diameter range that continues to the base portion. Thus, the buckling resistance of the extension portion is reduced, so that buckling is facilitated and a reduction in buckling resistance can be expected. Further, the tip shaft portion of the joint shaft or the torque transmission portion provided on the tip shaft portion contacts the step portion to transmit the impact load, and buckling deformation due to a relatively small load is caused by using the step portion as a starting point of deformation. This is done to reduce the buckling drag.
[0017]
  According to a second aspect of the present invention, in the impact drag reducing structure for a vehicle propeller shaft according to the first aspect,By axial movement of the front propeller shaftTo the torque transmission partAboveWith outer casethe aboveThe engagement with the joint shaft is released.
[0018]
According to the invention of claim 2, when the amount of the joint shaft entering is restricted, the engagement between the outer case and the joint shaft by the torque transmitting portion is released, and the rear propeller shaft coupled to the outer case extension and the outer case The buckling of the extension portion and the rear propeller shaft can be efficiently absorbed.
[0023]
  Claim3The invention described in claim 1Or 2In the structure for reducing the impact drag of the propeller shaft for a vehicle as described above, the load transmission means includes:To face the end of the outer case,Center bearing that rotatably supports the joint shaft on the vehicle bodySet inIt is characterized by being a protruding part.
[0024]
  Claim3According to the invention described in (4), the load transmitting means can be formed with a simple configuration in which a convex portion is provided on the existing center bearing portion, and the convex portion abuts on the end portion of the outer case, so that the impact load is specified in the outer case. By transmitting to the part, the rear propeller shaft coupled to the outer case can be buckled in a desired direction.
[0025]
  Claim4The invention described in claim 13One ofDescribed in item 1In the structure for reducing the impact resistance of the propeller shaft for a vehicle, the curvature of the large diameter range and the continuous portion of the stepped portion is,the aboveSmall diameter range andthe aboveIt differs from the curvature of the continuous part of the step part.
[0026]
  Claim4According to the invention, by increasing the curvature of the step portion and the continuous portion of the large diameter range with respect to the continuous portion of the small diameter range and the step portion, the portion where the sudden change in the cross section is formed to a relatively large diameter, and the large diameter side is impacted. The load can be easily absorbed, and the strength reduction of the small diameter portion with respect to the rotational torque can be avoided. Further, by reducing the curvature of the continuous portion of the stepped portion and the large diameter range with respect to the continuous portion of the small diameter range and the stepped portion, the small diameter side can easily absorb the impact load.
[0027]
  According to a fifth aspect of the present invention, in the impact resistance reduction structure for a vehicle propeller shaft according to the first or second aspect, the small diameter range includes a cylindrical first small diameter range continuous to the base portion, and the rear propeller. A first step that is configured to have a cylindrical second small diameter range that is coupled to the shaft, and that the stepped portion expands rearward continuously from the first small diameter range and continues to the large diameter range. And a second stepped portion that continues to the second small diameter range and is continuous with the large diameter range, and the load transmission means regulates the amount of the joint shaft entering. When the torque transmission portion is the second stepped portion.And a continuous portion of the second small diameter rangeIt is characterized by that.
[0028]
  Claim5According to the invention, the tip shaft portion or the torque transmission portion of the joint shaft abuts the second stepped portion and the continuous portion of the second small diameter range, and an impact load is input to the portion, and the portion is the starting point of buckling deformation. Thus, it becomes possible to buckle and deform more smoothly, improve the absorption of impact load by the propeller shaft, and improve the reliability.
[0029]
  Claim6The invention described in claim 15One ofDescribed in item 1In the vehicle propeller shaft impact drag reducing structure, the end of the extension is frictionally joined to the front end of the hollow cylindrical shaft tube of the rear propeller shaft.
[0030]
  Claim6According to the invention, by joining the end of the extension part and the shaft tube by friction welding, the joining strength can be ensured, and the extension part and the shaft tube due to welding heat do not cause “drop-off” as in the case of arc welding. The part and shaft tube can be made thinner, and the weight of the propeller shaft can be expected.
[0031]
  Claim7The invention described in claim 16One ofDescribed in item 1In the structure for reducing the impact resistance of a vehicle propeller shaft, the torque transmission portion isAddressProvided on the end shaft,AroundLeaveAn inner race in which a plurality of ball grooves extending in the axial direction are formed; a ball groove formed in the inner periphery of the base portion of the outer case and extending in the axial direction opposite to the ball grooves;eachAnd a plurality of balls fitted between the ball grooves.
[0032]
  Claim7This invention is a specific structure of the torque transmission part, and the torque transmission part is fitted into a ball groove formed opposite to the inner race and the base part of the outer case provided on the tip shaft part of the joint shaft. They can be formed by so-called double offset joints.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an impact drag reducing structure for a vehicle propeller shaft according to the present invention will be described below with reference to the drawings.
[0036]
(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. In each figure, an arrow F indicates the vehicle body front direction.
[0037]
FIG. 1 is an overall perspective view of a propeller shaft 1 used in a drive system of a four-wheel drive vehicle or a front engine rear drive vehicle. The propeller shaft 1 includes a front propeller shaft 2 and a rear propeller shaft 5 connected to a rear end portion of the front propeller shaft 2 via a joint 10. A front end portion of the front propeller shaft 2 is connected via a universal joint 7 to an output shaft of a power unit including an engine (not shown) mounted on the front portion of the vehicle body and a transmission mechanism. On the other hand, the rear end portion of the rear propeller shaft 5 is connected via a universal joint 8 to a rear wheel differential device which is a driving wheel (not shown). Further, the joint 10 for connecting the front propeller shaft 2 and the rear propeller shaft 5 is rotatably supported on the lower surface 61 of the vehicle body 60 by the center bearing portion 40 as shown in a perspective view of a main part at the lower part of the vehicle body. .
[0038]
3 is a cross-sectional view taken along the line II of FIG. 1 showing a connecting portion between the rear end portion of the front propeller shaft 2 and the front end portion of the rear propeller shaft 5 that form the impact drag reduction structure of the propeller shaft 1. 4 is an enlarged view of part A in FIG. 3, and FIG. 5 is an enlarged view of part B in FIG.
[0039]
The joint 10 has a joint shaft 11 coupled to the rear end portion of the front propeller shaft 2 and an outer case 20 coupled to the front end portion of the rear propeller shaft 5.
[0040]
The joint shaft 11 is made of a sheet metal that forms the front propeller shaft 2 and is connected to the rear end portion 3a of the hollow cylindrical shaft tube 3. The columnar base portion 12 is connected to the rear end of the base portion 12 via a step portion 12b. The main shaft portion 13 having a smaller diameter than the continuous base portion 12 and the tip shaft portion 14 having a smaller diameter than the main shaft portion 13 continuing to the rear end of the main shaft portion 13 via a step portion 13b are coaxially and continuously formed. Is formed.
[0041]
In the joint shaft 11, a front end portion 12 a of a base portion 12 formed in a ring shape is integrally coupled to a rear end portion 3 a of the shaft tube 3 by friction welding. By friction welding the front end portion 12a of the joint shaft 11 and the rear end portion 3a of the shaft tube 3 in this way, there is a concern that the thin base portion 12 and the shaft tube 3 may be generated by welding heat in the case of arc welding. It is possible to prevent “melting off”, and the base 12 and the shaft tube 3 can be thinned, and weight reduction of the front propeller shaft 2 can be expected.
[0042]
An annular inner race 16 in which a plurality of ball grooves 16 a extending along the axial direction is formed on the outer periphery of the joint shaft 11 is attached by spline fitting and fixed by a clip 17. The
[0043]
On the other hand, the outer case 20 coupled to the front end portion of the rear propeller shaft 5 includes a cylindrical base portion 21 and an extension portion formed integrally and continuously with the base portion 21 by machining as shown in FIGS. 22 is formed in a substantially cylindrical shape.
[0044]
A plurality of ball grooves 21 a extending in the axial direction are formed on the inner peripheral surface of the base portion 21 so as to face the ball grooves 16 a of the inner race 16. Further, an annular clip groove 21b is formed along the front end of each ball groove 21a on the inner peripheral surface of the base portion 21, and an annular joint cap mounting portion 21c is formed along the rear end of each ball groove 21a. Yes.
[0045]
The extended portion 22 includes a cylindrical small diameter range 23 that is continuous from the rear end of the base portion 21 with the same diameter, a step portion 24 in which the inner peripheral end continuously expands at the rear end of the small diameter range 23, and the step A cylindrical large-diameter range 25 having a front end continuous to the outer peripheral end of the portion 24 and continuing to the rear with the same diameter is continuously formed. Here, in particular, with respect to the curvature of the continuous portion 26 between the rear end of the small diameter range 23 and the inner peripheral end of the step portion 24 in the cross-sectional shape, the continuous portion 27 of the outer peripheral end of the step portion 24 and the front end of the large diameter range 25 Increase the curvature of the cross-sectional shape. The curvatures of the continuous portions 26 and 27 can be easily processed into a predetermined shape by machining with less processing restrictions. The cross-sectional shape of the continuous portion 27 between the outer peripheral end of the step portion 24 and the front end of the large-diameter range 25 with respect to the curvature of the continuous portion 26 between the rear end of the small-diameter range 23 and the inner peripheral end of the step portion 24 in the cross-sectional shape. The curvature of may be set small.
[0046]
The outer case 20 is press-fitted with a joint cap 28 having a disc shape and a flange formed on the outer periphery thereof into the joint cap mounting portion 21c, thereby dividing the inside into a base portion 21 side and an extension portion 22 side. The end 22a of the extension 22 formed in a ring shape is integrally coupled to the front end 6a of the shaft tube 6 made of sheet metal and forming the rear propeller shaft 5 by friction welding. In other words, the end 22a of the machined outer case 20 and the front end 6a of the shaft tube 6 made of sheet metal are friction-welded, so that oxides and other foreign matters at the joint are pushed out of the welding surface by the pressure contact force. Thus, a uniform joint structure can be obtained, the joint strength can be secured, and there is no “melt-off” between the extension portion 22 and the shaft tube 6 that may be generated by welding heat as in arc welding, and the extension portion 22 and the shaft tube 6 are not melted. Thinning is possible, and weight reduction of the rear propeller shaft 5 can be expected.
[0047]
Furthermore, the balls 31 held by the ring-shaped gauges 30 are fitted and mounted in the respective ball grooves 16a formed on the outer periphery of the inner race 16 disposed on the distal end shaft portion 14 of the joint shaft 11. The inner race 16 fitted with the gauge 30 and the ball 31 is inserted into the outer case 20, and the gauge 30 is inserted between the ball grooves 16 a of the inner race 16 and the ball grooves 21 a of the base portion 21 facing each other. The held ball 31 is fitted. The joint shaft 11 and the outer case 20 are moved in the axial direction by the ball groove 16a of the inner race 16 attached to the joint shaft 11, the ball groove 21a of the outer case 20, and the ball 31 fitted in the ball grooves 16a and 21a. A torque transmitting portion 10A that engages freely and transmits rotational torque is formed.
[0048]
Further, a ring-shaped clip 32 is fitted and mounted in the clip groove 21b to prevent the inner race 16 from coming out of the outer case 20. A cylindrical boot 33 made of an elastic member such as rubber is provided between the outer case 20 and the distal end shaft portion 14 of the joint shaft 11 in order to protect the lubricant in the outer case 20 and prevent foreign matter from entering from the outside. It is sealed by.
[0049]
The joint 10 thus configured includes an inner race 16 provided on the tip shaft portion 14 of the joint shaft 11 attached to the front propeller shaft 2, an outer race 21, an inner race 16 and an outer race attached to the rear propeller shaft 5. A rotational torque is transmitted between the front propeller shaft 2 and the rear propeller shaft 5 at a constant speed by a ball 31 or the like fitted between the ball grooves 16a and 21a formed in the case 21, and the relative angle and axial direction of each other. A double offset joint (DOJ) that allows relative movement of the two is constituted.
[0050]
Next, the center bearing portion 40 that supports the joint 10 on the lower surface 61 of the vehicle body 60 will be described with reference to FIGS. 2 and 4.
[0051]
The center bearing portion 40 includes a bearing 41 fitted to the joint shaft 11, an inner cylinder member 42 fixed to the outer periphery of the bearing 41, and an outer cylinder member connected to the outer periphery of the inner cylinder member 42 via an insulator 43. 44 and a bracket 53 for attaching the outer cylinder member 44 to the lower surface 61 of the vehicle body 60.
[0052]
  The bearing 41 has a stepped portion and a cylindrical spacer 47 whose inner race 41 a is fitted to the main shaft portion 13 of the joint shaft 11 and is locked to a clip 46 that is fitted to a clip groove formed in the main shaft portion 13. 12bIt is supported by being sandwiched between.
[0053]
The inner cylinder member 42 has a main body portion 42a fitted to the outer periphery of the outer race 41b of the bearing 41, a large-diameter portion 42b formed in an annular shape by expanding from the main body portion 42a, and the outer race 41b from the main body portion 42a. It is formed in a substantially cylindrical shape integrally formed with a small diameter portion 42 d extending in a cylindrical shape along the spacer 47 via a stepped portion 42 c that decreases in diameter along the rear surface. Furthermore, the convex part 48 which is a load transmission part means extended from the level | step-difference part 42c along the upper surface of the small diameter part 42d and facing the upper part of the front-end part of the outer case 20 is provided. The distance from the convex portion 48 to the front end of the outer case 10 and the distance from the inner race 16 to the step portion 24 in the joint 10 are set to be approximately equal.
[0054]
  Of the inner cylinder member 42Large diameter part 42bA retainer 49 formed in an annular shape with a substantially C-shaped or U-shaped cross section is provided therein. On both sides of the bearing 41, ring-shaped oil seals 51a and 51b for sealing between the retainer 49 and the small diameter portion 42d of the inner cylinder member 42 and the joint shaft 11 are disposed.
[0055]
The insulator 43 is made of an elastic member such as rubber. The insulator 43 is formed in an annular shape having a substantially C-shaped cross section in which an inner periphery is coupled to the inner cylinder member 42 and an outer periphery is coupled to the outer cylinder member 44. The cylindrical portion 43 b extends from the insulator portion 43 a along the inner cylinder member 42 and covers the small-diameter portion 44 d and the convex portion 48.
[0056]
A bracket 53 for fixing the outer cylinder member 44 to the vehicle body is attached to the outer cylinder member 44. As shown in FIGS. 1 and 2, the bracket 53 has a belt-like shape that is coupled along the lower surface of the outer cylinder member 44, and a bolt whose front side of the vehicle body is opened in a slit shape at mounting portions 54 formed at both ends thereof. A hole 55 is formed and attached to the lower surface 61 of the vehicle body 60 by a bolt 56 penetrating the bolt hole 55. With this configuration, the mounting portion 54 is damaged by an impact load from the front direction of the vehicle body that is greater than or equal to a predetermined value, and is dropped from the lower surface 61 of the vehicle body 60.
[0057]
Next, the action of the impact drag reducing structure of the propeller shaft 10 configured as described above will be described.
[0058]
  In normal travel, the rotational torque from the power unit is transmitted from the front propeller shaft 2 to the rear propeller shaft 5 via the joint 10, and is transmitted from the rear propeller shaft 5 to the rear wheels via the differential device. During this travel, the relative movement in the axial direction of the front propeller shaft 2 and the rear propeller shaft 5 is allowed by the joint 10.,carVia the propeller shaft 1 that accompanies the swinging of the power unit and the differential device at the time of both start, sudden braking or bump / reboundPower unitFrom the differential device side and from the differential device sidePower unitVibration transmission to the side is prevented, and vibration transmission to the vehicle body 60 is reduced. Further, the propeller shaft 1 is rotated at high speed by rotatably supporting the joint 10 connecting the front propeller shaft 2 and the rear propeller shaft 5, which is an intermediate portion of the propeller shaft 1, to the vehicle body 60 via the center bearing portion 40. As a result, the vibration and noise of the vehicle are effectively suppressed, and the improvement in ride comfort and comfort can be ensured.
[0059]
On the other hand, when an impact load of a predetermined level or more is applied from the front of the vehicle body to the front of the vehicle body due to a vehicle collision or the like, if the power unit moves toward the rear of the vehicle body due to the impact load, that is, retreats, the front via the universal joint 7 An impact load acts on the propeller shaft 2, and the front propeller shaft 2 moves backward. As the front propeller shaft 2 moves backward, the center bearing portion 40 that supports the joint shaft 11 moves backward, and when the center bearing portion 40 moves slightly, the mounting portion 54 of the bracket 53 that is coupled to the vehicle body 60 with the bolt 56 is moved. The joint 10 is dropped together with the center bearing portion 40 due to breakage. The relationship with the vehicle body 60 is cut off by the dropping of the joint 10, and the front propeller shaft 2 can be easily retracted.
[0060]
As the front propeller shaft 2 moves backward, the joint shaft 11 is caused to roll by the balls 31 fitted between the ball grooves 21a of the outer case 20 attached to the rear propeller shaft 5 and the ball grooves 16a of the inner race 16. It enters the outer case 20 smoothly with an extremely small load and moves backward. When the joint shaft 11 enters the outer case 20, the joint cap 28 fitted and supported by the joint cap mounting portion 21 c is pushed and removed at the tip of the tip shaft portion 14, and the inner race 16 is moved forward by the joint shaft 11 retreating. , The ball 31 comes out of the ball groove 21a of the outer case 20 and the engagement between the joint shaft 11 and the outer case 20 is released.
[0061]
Due to the contraction of the propeller shaft 1 accompanying the retraction of the front propeller shaft 2, the propeller shaft 1 is prevented from being stretched against the vehicle body, so that the vehicle body is easily deformed. Relaxation is obtained.
[0062]
Thereafter, as shown in FIG. 6, the convex portion 48 provided on the center bearing portion 40 that retreats integrally with the front propeller shaft 2 hits the upper front end of the outer case 20, and the amount of entry of the joint 11 into the outer case 20 is increased. The impact load that is restricted and the front propeller shaft 2 is retracted is input from the convex portion 48 of the center bearing portion 40 to the outer case 20 coupled to the front end portion of the rear propeller shaft 5.
[0063]
The outer case 20 to which an impact load is input from the front is buckled by the small diameter range 23 of the extension 22 and the continuous portion 26 of the stepped portion 24 and the continuous portion 27 of the stepped portion 24 and the large diameter range 25 whose cross-sectional shape changes suddenly. Deforms to absorb impact load and relieve impact. In particular, since the stepped portion 24 formed with a relatively large curvature and the continuous portion 27 of the large diameter range 25 are buckled and deformed with a relatively small load, a smooth impact load absorption characteristic can be obtained, and an effective impact can be obtained. Mitigation can be ensured.
[0064]
In buckling deformation of the outer case 20, the stepped portion 24 formed in the extension portion 22 and the continuous portion 27 of the large diameter range 25 become the starting point of deformation and are smoothly buckled and deformed by a relatively small load. A reduction in yield strength is obtained. The large diameter range 25 and the shaft tube 6 are formed to have a large diameter through the step portion 24 with respect to the small diameter range 23 in which the extended portion 22 of the outer case 20 continues to the base portion 21, and the outer case 20 and the shaft tube 6 enter the outer case 20. The interference of the tip shaft portion 14 of the joint shaft 11 and the inner race 16 is suppressed, the buckling resistance of the extension portion 22 of the outer case 20 can be reduced, the buckling is facilitated, and the buckling resistance can be further reduced. .
[0065]
Further, when the convex portion 48 and the front end portion of the outer case 20 come into contact with each other, the inner race 16 provided on the distal end shaft portion 14 of the joint shaft 11 comes into contact with the step portion 24, and the distal end shaft portion 14 and the inner race 16 The impact load from the front propeller shaft 2 acts intensively on the portion, and a bending force is applied to the shaft tube 6 of the rear propeller shaft 5. By this bending force, the buckling deformation of the shaft tube 6 can be executed smoothly following the buckling deformation of the outer case 20, and the impact load due to the deformation of the rear propeller shaft 5 can be absorbed smoothly. In particular, when the rear propeller shaft 5 is buckled and deformed, the rear end upper portion of the outer case 20 is pressed by the convex portion 48 of the center bearing portion 40 that retreats together with the front propeller shaft 2, and the rotation angle of the propeller shaft 1 after the collision is fine. Therefore, it is possible to avoid the problem that the front portion of the rear propeller shaft 5 is effectively pushed down to damage the lower surface 61 of the vehicle body 60 by the propeller shaft 1 and the fuel tank disposed on the lower surface 61.
[0066]
Therefore, the propeller shaft 1 contracts with a very small load over the entire range from the start of retraction of the power unit due to a vehicle collision until the convex portion 48 of the center bearing portion 40 contacts the outer case 20, and the propeller shaft 1 is stretched. The power unit can be retracted without any impact, and the impact load can be absorbed smoothly by the deformation of the front part of the vehicle body. Further, even after the convex portion 48 abuts against the outer case 20, the impact load can be absorbed gently by the deformation of the extended portion 22 whose cross-sectional shape changes suddenly, and effective impact resistance can be reduced. The impact can be reduced by the deformation of the part and the deformation of the propeller shaft 1.
[0067]
Further, the curvature of the continuous portion 27 of the stepped portion 24 and the large diameter range 25 is increased with respect to the continuous portion 26 of the small diameter range 23 and the stepped portion 24 of the outer case 20, and the continuous portion is formed so as to change suddenly. Although there is a concern about a decrease in strength with respect to the transmission of the rotational torque 27, a sufficient strength can be ensured because the portion is formed with a large diameter.
[0068]
In addition, there is no change with time in the characteristics of the joint 10, the front propeller shaft 2, and the rear propeller shaft 5, and it is extremely possible to predict in advance the behavior characteristics of the propeller shaft 1 when an impact load is actually applied based on experiments or simulations. The basic configuration is the same as that of a conventional propeller shaft, and the behavior characteristics of the propeller shaft 1 can be predicted more easily and the behavior characteristics can be easily tuned.
[0069]
Although the detailed description is omitted by attaching the same reference numerals to the portions corresponding to those in FIGS. 1 to 6 in FIG. 7, the center bearing portion 40 is integrated with the front propeller shaft 2 without providing the convex portion 48. The amount of entry of the joint 11 into the outer case 20 is regulated by the inner cylindrical member 42 of the center bearing portion 40 that moves backward, and the impact load due to the backward movement of the front propeller shaft 2 is rearward from the inner cylindrical member 42 in the center bearing portion 40. You may make it input into the outer case 20 couple | bonded with the front-end part of the propeller shaft 5. FIG.
[0070]
(Second Embodiment)
FIG. 8 is a cross-sectional view corresponding to FIG. 6 showing the outline of the second embodiment of the impact drag reducing structure of the present invention. In FIG. 8, parts corresponding to those in FIGS. 1 to 6 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0071]
In the present embodiment, the outer case 20 of the joint 10 coupled to the front end of the rear propeller shaft 5 is opposed to each ball groove 16a of the inner race 16 on the inner peripheral surface of the base portion 21 as in the first embodiment. Thus, a plurality of ball grooves 21a are formed extending in the axial direction.
[0072]
The extended portion 72 continuously formed on the base portion 21 includes a cylindrical first small diameter range 73 that is continuous from the rear end of the base portion 21 with the same diameter, and an inner peripheral end that extends continuously from the rear end of the small diameter range 73. A first stepped portion 74 having a diameter, a large-diameter range 75 in which the front end is continuous to the outer peripheral end of the first stepped portion 74 and the same diameter in the rear, and an outer peripheral end is continuous to the rear end of the large-diameter range 75. A second stepped portion 76 having a reduced diameter and a second small diameter range 77 having a front end continuous with the inner peripheral end of the second stepped portion 76 are continuously formed, and an end 72a of the second small diameter range 77 is a shaft of the rear propeller shaft 5. The front end 6a of the tube 6 is coupled by friction welding.
[0073]
The curvature of the continuous portion of the first stepped portion 74 and the large diameter range 75 is larger than the continuous portion of the first small diameter range 73 and the first stepped portion 74, and the continuous portion of the second stepped portion 76 and the second small diameter range 77 On the other hand, the curvature of the continuous portion of the large diameter range 75 and the second stepped portion 76 is set large.
[0074]
Further, the continuous portion of the second stepped portion 76 and the second small diameter range 77 is formed so that the front propeller shaft 2 moves backward as the power unit due to an impact load acting on the front portion of the vehicle body from the front of the vehicle body due to a vehicle collision moves backward. In a state where the convex portion 48 of the portion 40 hits the front end upper portion of the outer case 20, the tip shaft portion 14 or the inner race 16 of the joint shaft 11 is set to a position where it abuts. Other configurations are the same as those of the first embodiment.
[0075]
With this configuration, in addition to the first embodiment, when the convex portion 48 provided in the center bearing portion 40 that retreats integrally with the front propeller shaft 2 contacts the upper front end of the outer case 20, the joint shaft 11 end shaft portion 14 or inner race 16 abuts on a continuous portion of second stepped portion 76 and second small diameter range 77 and an impact load is input to this portion, and this portion becomes a starting point for deformation of outer case 20. Thus, buckling deformation can be more reliably performed, and the absorption of impact load by the propeller shaft 1 is improved, thereby improving the reliability.
[0076]
Note that the curvature of the continuous portion of the first stepped portion 74 and the large diameter range 75 is set smaller than the continuous portion of the first small diameter range 73 and the first stepped portion 74, and the second stepped portion 76 and the second small diameter range 77 You may set the curvature of the continuous part of the large diameter range 75 and the 2nd level | step-difference part 76 small with respect to a continuous part.
[0089]
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, in the first embodiment and the second embodiment described above, the convex portion 48 of the center bearing portion 40 is disposed so as to face the upper front end of the outer case 20, but a desired buckling direction of the rear propeller shaft 5 is provided. The arrangement position can be changed according to the above.
[0090]
Further, in the second embodiment, the curvature of the continuous portion of the first stepped portion 74 and the large diameter range 75 is set smaller than the continuous portion of the first small diameter range 73 and the first stepped portion 74, and the second stepped portion. The curvature of the continuous portion of the large diameter range 75 and the second stepped portion 76 can be set smaller than the continuous portion of 76 and the second small diameter range 77.
[0092]
【The invention's effect】
According to the impact drag reduction structure for a vehicle propeller shaft according to the present invention described above, when an impact load is applied from the front of the vehicle body, the joint shaft is attached to the rear propeller shaft as the front propeller shaft moves backward. The torque transmitting portion disposed between the joint shafts smoothly enters the outer case with an extremely small load, and the propeller shaft contracts. By shortening the propeller shaft, the propeller shaft is prevented from being stretched, so that the impact load due to the deformation of the vehicle body is surely absorbed and the impact can be reduced. Thereafter, when the load transmitting means comes into contact with the outer case, the impact load is transmitted to the outer case, and the small diameter range of the extension portion and the continuous portion of the step portion and the continuous portion of the step portion and the large diameter range are buckled and deformed. The impact load can be absorbed and the impact reduced. Furthermore, the characteristics of the joint, the front propeller shaft, and the rear propeller shaft do not change with time, and it is extremely easy to predict the behavior characteristics of the propeller shaft based on experiments or simulations, and the behavior characteristics can be easily tuned.
[0093]
In addition, according to the impact resistance reduction structure for a propeller shaft for a vehicle according to the present invention, when an impact load is applied from the front of the vehicle body, the small diameter range of the extension portion of the joint shaft and the continuous portion of the stepped portion as the front propeller shaft retracts. In addition, the step portion and the continuous portion of the large diameter range are buckled and deformed, so that it is possible to efficiently absorb the impact load due to the deformation of the vehicle body, and the impact can be reduced.
[Brief description of the drawings]
FIG. 1 is an overall perspective view of a propeller shaft showing an outline of a first embodiment of a structure for reducing impact resistance of a propeller shaft for a vehicle according to the present invention.
FIG. 2 is a perspective view of a main part of a lower part of a vehicle body.
3 is a cross-sectional view taken along the line II of FIG. 1, showing a connecting portion between a front propeller shaft and a rear propeller shaft.
4 is an enlarged view of a part A in FIG. 3;
FIG. 5 is an enlarged view of part B in FIG. 3;
FIG. 6 is a cross-sectional view showing an outline of an impact drag reducing action by the propeller shaft.
FIG. 7 is a cross-sectional view showing a modification of the present embodiment.
FIG. 8 is a cross-sectional view of a connecting portion between a front propeller shaft and a rear propeller shaft, showing an outline of a second embodiment of the present invention.
FIG. 9 is an explanatory diagram showing an outline of a conventional drive system.
FIG. 109In the C section enlarged view ofis there.
[Explanation of symbols]
1 Propeller shaft
2 Front propeller shaft
3 Shaft tube
3a Rear end
5 Rear propeller shaft
6 Shaft tube
6a Front end
10 Joint
10A Torque transmission part
11 Joint shaft
12 base
13 Spindle part
14 Tip shaft
16 Inner race
16a Ball groove
20 Outer case
21 Base part
21a Ball groove
22 Extension
22a end
23 Small diameter range
24 steps
25 Large diameter range
26 continuous parts
27 continuous parts
31 balls
40 Center bearing
42 Inner cylinder member
48 Convex (load transmission means)
53 Bracket
54 Mounting part
60 body
61 Bottom
72 Extension
73 1st small diameter range
74 First step
75 Large diameter range
76 Second step
77 2nd small diameter range
77a Rear end

Claims (7)

In the structure for reducing the impact resistance of a propeller shaft that extends along the longitudinal direction of the vehicle body and includes a front propeller shaft and a rear propeller shaft that is coupled to a rear end portion of the front propeller shaft via a joint.
The above joint is
A base portion and an extension portion that is integrally formed continuously rearward in the axial direction from the base portion, and an end portion is coupled to the front end portion of the rear propeller shaft, and the extension portion is substantially the same as the base portion. A cylindrical outer case in which a small diameter range formed in a diameter and a large diameter range having a diameter larger than the small diameter range are continuously formed via a stepped portion;
A joint shaft having a base portion coupled to a rear end portion of the front propeller shaft and a distal end shaft portion inserted into the outer case;
A torque transmitting portion that is disposed between the base portion and the tip shaft portion, engages the outer case and the joint shaft movably in the axial direction, and transmits rotational torque;
The axial movement of the front propeller shaft caused by the impact load from the front of the vehicle body abuts on the outer case to transmit the impact load to the outer case, and the amount of entry of the joint shaft into the outer case is reduced. A load transmitting means for regulating,
The structure for reducing the impact resistance of a propeller shaft for a vehicle, wherein the torque transmission portion comes into contact with the step portion when the amount of the joint shaft entering the outer case is restricted by the load transmission means.   The impact resistance reduction structure for a propeller shaft for a vehicle according to claim 1, wherein the engagement between the outer case and the joint shaft in the torque transmission portion is released by the axial movement of the front propeller shaft. . The load transmitting means is
The vehicle propeller shaft according to claim 1 or 2, wherein the vehicle propeller shaft is a convex portion provided in a center bearing portion that rotatably supports the joint shaft on a vehicle body so as to face an end portion of the outer case. Impact resistance reduction structure.   The vehicle propeller according to any one of claims 1 to 3, wherein a curvature of a continuous portion of the large diameter range and the stepped portion is different from a curvature of the continuous portion of the small diameter range and the stepped portion. Shaft impact drag reduction structure. The small-diameter range includes a cylindrical first small-diameter range that is continuous with the base portion, and a cylindrical second small-diameter range that is coupled to the rear propeller shaft.
The stepped portion expands rearward continuously from the first small diameter range, and the first stepped portion continues to the large diameter range and the rearward diameter decreases continuously from the large diameter range. And a second step portion continuous with the second small diameter range,
2. The torque transmitting portion abuts against a continuous portion between the second stepped portion and the second small diameter range when an amount of the joint shaft entering is restricted by the load transmitting means. 5. The impact resistance reduction structure for a vehicle propeller shaft according to any one of 4 above. The end of the extension is
The impact resistance reduction structure for a propeller shaft for a vehicle according to any one of claims 1 to 5, wherein the structure is friction-bonded to a front end portion of a hollow cylindrical shaft tube of the rear propeller shaft. The torque transmission part is
An inner race provided in the tip shaft portion and formed with a plurality of ball grooves extending in the axial direction on the outer periphery;
A ball groove formed on the inner periphery of the base portion of the outer case so as to extend in the axial direction so as to face the ball groove;
The impact resistance reduction structure for a propeller shaft for a vehicle according to any one of claims 1 to 6, further comprising a plurality of balls fitted between the ball grooves.

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