JP2013133012A - Power transmission device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent grounding in a connection section, even if a relative moving amount to a vehicle body of a driving source is large at the time of front collision.SOLUTION: A power transmission device includes: a propeller shaft 12, which extends to a front-back direction of a vehicle body 11 and in which a front end is connected to a transfer output shaft 18 through a hook type joint 14a and a rear end is connected to an input shaft 22 of a differential mechanism 20 through the other hook type joint 14b; a center bearing support 26, which supports the propeller shaft 12 so as to be rotatable to the vehicle body 11; and a fall prevention belt 38a, which has a mounting section 36 mounted on the vehicle body and supports the propeller shaft 12 when the propeller shaft 12 falls; wherein a withstand load (F2), in the mounting section 36 of the fall prevention belt 38a, and a withstand load (F3) of the fall prevention belt 38a itself are set larger than a bending load (F1) of the propeller shaft 12 (F1<F2, F3).

Description

  The present invention relates to a vehicle power transmission device that transmits power to a rear wheel by means of a propeller shaft.

  For example, in an FR (front engine / rear drive system) vehicle or a 4WD (4 wheel driving) vehicle, in order to transmit the driving force from a driving source such as an engine / transmission mounted on the front of the vehicle body to the rear wheels, A propeller shaft extending in the front-rear direction of the vehicle body is provided.

  For example, as disclosed in Patent Document 1, the propeller shaft is generally configured by a front shaft and a rear shaft that are divided into two in the front and rear directions. The front shaft and the rear shaft are connected by a constant velocity universal joint. The front end of the front shaft is connected to an output shaft on the drive source side (a transmission shaft in an FR vehicle, a transfer output shaft in a 4WD vehicle) via an inconstant universal joint.

  Further, the rear end of the rear shaft is connected to an input shaft of a differential mechanism that distributes driving force to the left and right rear wheels via an inconstant universal joint. Furthermore, the rear end of the front shaft or the front end of the rear shaft is rotatably supported with respect to the vehicle body by a support mechanism (center bearing support).

Japanese Patent No. 4739913

  By the way, when the vehicle collides frontward with an obstacle or another vehicle, only the vehicle body moves forward by inertial force while the drive source such as the engine / transmission is almost stationary. In other words, a drive source such as an engine / transmission moves relative to the vehicle body, and the impact at the time of a frontal collision is absorbed by this relative movement.

  In a vehicle equipped with a propeller shaft extending in the longitudinal direction of the vehicle body, such as an FR vehicle or a 4WD vehicle, when the impact is input, a connecting portion between the front shaft and the rear shaft with the constant velocity universal joint being bent. The propeller shaft is bent, the drive shaft is bent at the connecting portion between the output shaft on the driving source and the propeller shaft (front shaft) with the inconstant universal joint being bent, and the input shaft of the differential mechanism and the propeller shaft ( The relative movement is allowed by bending at the connecting portion with the rear shaft).

  However, when the relative movement amount is large, the degree of bending at these connecting parts also increases, and in particular, the degree of bending at the connecting part between the input shaft of the differential mechanism and the propeller shaft increases. A connecting portion between the input shaft of the mechanism and the propeller shaft is grounded to the ground (see FIG. 6), and this grounding may make the shock absorbing performance due to the relative movement unstable.

  The present invention has been made in view of the foregoing points, and is a vehicle power transmission capable of avoiding grounding at a connecting portion even when a relative movement amount of a drive source with respect to a vehicle body is large at the time of a frontal collision. An object is to provide an apparatus.

In order to achieve the above object, the present invention extends in the front-rear direction of the vehicle body, the front end is connected to the output shaft on the drive source side via the first universal joint, and the rear end is connected via the second universal joint. A propeller shaft coupled to the input shaft of the moving mechanism, a support mechanism for rotatably supporting the propeller shaft relative to the vehicle body between the front end and the rear end, and between the front end and the support mechanism In the vehicle power transmission device, including a mounting portion that is attached to the vehicle body across the lower side of the propeller shaft, and a fall prevention band that supports the propeller shaft when the propeller shaft falls.
When a downward load acting on the front end of the propeller shaft is increased in a state where the propeller shaft is supported by the fall prevention band, the fall prevention band is broken or the attachment of the fall prevention band is performed. The load-proof load and the fall prevention in the attachment part of the fall prevention band so that the propeller shaft on the front end side of the fall prevention band is bent downward from the fall prevention band before the breakage in the part occurs. The load resistance of the belt itself is set larger than the bending load of the propeller shaft.

  According to the present invention, the front collision of the propeller shaft and the output shaft on the drive source side occur as the vehicle collides frontward with an obstacle or another vehicle and the backward movement of the drive source relative to the vehicle body starts. The connecting portion bends with the first universal joint being bent, and at this time, the front end of the propeller shaft receives a downward load.

  As the drive source moves backward relative to the vehicle body, the downward load increases. In the present invention, the load resistance (F2) at the mounting portion of the fall prevention band and the load resistance of the fall prevention band itself ( Since F3) is set to be larger than the folding load (F1) of the propeller shaft (F1 <F2, F3), the position where the propeller shaft on the front end side from the fall prevention band is supported by the fall prevention band is set downward as the break point. Bends.

  As described above, according to the present invention, the propeller shaft itself is bent at a position where the propeller shaft itself is supported by the fall prevention band at the time of a frontal collision of the vehicle, and accordingly, the rear end of the propeller shaft and the input shaft on the differential mechanism side are connected to each other. The degree of bending of the connecting portion by the second universal joint to be connected can be reduced as compared with the conventional case.

  As a result, according to the present invention, the grounding of the connecting portion between the input shaft of the differential mechanism and the rear end of the propeller shaft is avoided, and the shock absorbing performance due to the rearward movement of the drive source relative to the vehicle body is avoided. Can be stabilized.

  The attachment portion includes both a vehicle body side attachment portion to which the fall prevention band is directly attached and a band prevention portion of the fall prevention band attached to the vehicle body.

  According to the present invention, it is possible to obtain a vehicular power transmission device capable of avoiding grounding at the connecting portion even when the amount of relative movement of the drive source with respect to the vehicle body is large at the time of a frontal collision.

1 is a schematic configuration diagram of a vehicle power transmission device according to an embodiment of the present invention. (A) is a longitudinal sectional view taken along the line A1-A1 in FIG. 1, (b) is a longitudinal sectional view taken along the line A2-A2 in FIG. 1, and (c) is a line A3-A3 in FIG. It is a longitudinal cross-sectional view along line. (A) is a characteristic diagram showing the bending load of the propeller shaft with respect to the displacement amount, (b) is a characteristic diagram showing a load resistance of the vehicle body side mounting portion with respect to the displacement amount, and (c) is a fall prevention band itself with respect to the displacement amount. It is a characteristic view which shows the load resistance of. FIGS. 4A to 4D are side views showing, in time series, a state where the propeller shaft is deformed when the vehicle collides with the front. FIG. 5 is an enlarged side view of FIG. In prior art, it is a side view which shows the state which the connection part of the input shaft of a differential mechanism and a propeller shaft grounded to the ground.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. 1 is a side view of a vehicle power transmission device according to an embodiment of the present invention, FIG. 2 (a) is a longitudinal sectional view taken along line A1-A1 of FIG. 1, and FIG. 2 (b) is FIG. FIG. 2C is a longitudinal sectional view taken along line A3-A3 in FIG. In the drawings, “front and rear” indicates the vehicle body longitudinal direction, and “left and right” indicates the vehicle width direction.

  As shown in FIG. 1, the vehicle power transmission device 10 includes a propeller shaft 12 extending in the front-rear direction of the vehicle body 11. The front end of the propeller shaft 12 is connected to a transfer output shaft 18 of a transmission (transmission) 16 via a hook-type joint (first universal joint) 14a, and the rear end of the propeller shaft 12 is connected to another hook-type joint (first joint). 2 universal joint) 14b, and is connected to the input shaft 22 of the differential mechanism 20. The front portion of the differential mechanism 20 is supported on the vehicle body 11 side via the mount member 23, and the rear portion of the differential mechanism 20 is fixed to a cross member (not shown) via a bolt.

  The propeller shaft 12 includes a front shaft 12a and a rear shaft 12b. The front shaft 12a includes a hook joint 14a for connecting to the transfer output shaft 18 at the front end, and a cup portion of the constant velocity joint 24 at the rear end. The rear shaft 12b includes a spider portion housed in the cup portion at the front end portion, and another hook joint 14b for connecting to the input shaft 22 of the differential mechanism 20 at the rear end portion.

  In addition, in this embodiment, although demonstrated using the propeller shaft 12 divided | segmented into the front side shaft 12a and the rear side shaft 12b, it is not limited to this, A front side shaft and a rear side shaft are An integrally configured propeller shaft may be used.

  A center bearing support (support mechanism) 26 that rotatably supports the propeller shaft 12 (front end portion of the rear shaft 12b) with respect to the vehicle body 11 is provided at a substantially central portion between the front end and the rear end of the propeller shaft 12. Provided. As shown in FIG. 2B, the center bearing support 26 has a support bracket 30 for fixing and supporting the cross member 28 of the vehicle body 11 via bolts 29 and nuts 33, and a shaft portion 31. A plurality of ball bearings 32 that are supported in the circumferential direction are provided between a bearing member 34 arranged in the circumferential direction, and the support bracket 30 and the bearing member 34, and are formed by an elastic body such as rubber, not shown. And a support member. In FIG. 2B, reference numeral 44 indicates a floor panel.

  Mounting portions that are attached to the vehicle body 11 across the lower side of the propeller shaft 12 between the front end of the propeller shaft 12 and the center bearing support 26 and between the center bearing support 26 and the rear end of the propeller shaft 12, respectively. 36, and two fall prevention bands 38a and 38b are provided to support the propeller shaft 12 when the propeller shaft 12 falls (see FIGS. 2A and 2C). The attachment portion 36 includes both a band side attachment portion 36a for attaching the fall prevention bands 38a and 38b to the vehicle body 11 and a vehicle body side attachment portion 36b for attaching the band side attachment portion 36a to the vehicle body 11. .

  The front drop prevention band 38a has a function of receiving the propeller shaft 12 (front shaft 12a) and preventing the propeller shaft 12 from falling when the front hook joint 14a and the transfer output shaft 18 are detached. The rear fall prevention band 38b functions to prevent the propeller shaft 12 from falling by receiving the propeller shaft 12 (rear side shaft 12b) when the rear hook joint 14b and the input shaft 22 of the differential mechanism 20 are disengaged. Have

  The front-side fall prevention band 38a provided between the front end of the propeller shaft 12 and the center bearing support 26 is made of a metal band formed in a curved shape (see FIG. 2A). A predetermined clearance 40 is provided between the outer peripheral surface. A bent flange portion 42 is provided at one end portion and the other end portion along the longitudinal direction of the belt-like body, and the flange portion 42 is provided with respect to the reinforcing member 46 provided integrally on the lower surface of the floor panel 44. Are fastened and fixed via bolts 48 and nuts 49. In this case, the flange part 42 functions as the band side attaching part 36a, and the reinforcing member 46 functions as the vehicle body side attaching part 36b.

  A rear-side fall prevention band 38b provided between the center bearing support 26 and the rear end of the propeller shaft 12 is formed of a metal band-like body having a substantially U-shaped cross section (see FIG. 2C). A predetermined clearance 40 is provided between the outer peripheral surface of the propeller shaft 12. A bent flange portion 42 is provided at one end portion and the other end portion along the longitudinal direction of the belt-like body, and the flange portion 42 is a bolt 52 with respect to the cross member 50 positioned on the lower side of the floor panel 44. And the nut 54 is fastened and fixed. In this case, the flange portion 42 functions as the band side mounting portion 36a, and the cross member 50 functions as the vehicle body side mounting portion 36b.

  The vehicle driving force transmission device 10 according to the present embodiment is basically configured as described above. Next, the operation and effects thereof will be described.

  FIG. 3 (a) is a characteristic diagram showing the bending load of the propeller shaft with respect to the displacement amount, FIG. 3 (b) is a characteristic diagram showing the load resistance of the vehicle body side mounting portion with respect to the displacement amount, and FIG. 3 (c) is a displacement diagram. It is a characteristic view which shows the load resistance of the fall prevention belt itself with respect to quantity. In addition, in each figure of Fig.3 (a)-(c), each displacement amount (mm) of a horizontal axis and each load (N) of a vertical axis | shaft are graduated on the same scale, respectively.

First, the bending load of the propeller shaft 12 was measured as follows.
In the state where only the front shaft 12a is used and both the rear end of the front shaft 12a and the portion supported by the fall prevention band 38a when the front shaft 12a falls are firmly fixed by a fixing member (not shown), A downward load was applied to the tip portion by a load applying means (not shown), and the amount of sagging of the tip portion was measured as a displacement amount. Moreover, the load provided to the location supported by the fall prevention belt | band | zone 38a of the front side shaft 12a was measured using the load meter. As a result, the front shaft 12a is supported by the fall prevention band 38a when the load applied to the place supported by the fall prevention band 38a reaches the predetermined load F1 indicated by the broken line in FIG. Was broken at the break point. The predetermined load F1 functions as a bending load of the propeller shaft 12.

Next, the load resistance of the vehicle body side attachment portion 36b was measured as follows.
In a state where the front drop prevention band 38a is attached to the vehicle body 11 via bolts 48 and nuts 49, a vertically downward load is applied as a tensile load to the drop prevention band 38a by load applying means (not shown). As a result, when the tensile load reaches a predetermined load F2 indicated by a broken line in FIG. 3B, the vehicle body side mounting portion 36b of the vehicle body 11 is damaged, and the bolt 48 that fastens the fall prevention band 38a and The nut 49 fell out of the vehicle body side attachment portion 36b. The predetermined load F2 functions as a load resistance at the attachment portion 36 of the fall prevention band 38a.

Next, the load resistance of the fall prevention band 38a itself was measured as follows.
This is basically the same as the case where the load resistance of the vehicle body side mounting portion 36b is measured, but the thickness of the vehicle body 11 to which the front side fall prevention band 38a is attached is increased to be stronger and more resistant to the fall prevention band 38a. A vertically downward load was applied as a tensile load by a load applying means (not shown). As a result, when the tensile load reached a predetermined load F3 indicated by a broken line in FIG. 3C, the fall prevention band 38a was broken from the flange portion 42. This predetermined load F3 functions as a load resistance of the fall prevention band 38a itself.

  From the above, the relationship between the bending load F1 of the propeller shaft 12, the load resistance F2 at the mounting portion 36 of the fall prevention band 38a, and the load resistance F3 of the fall prevention band 38a itself is as follows. The load F2 and the load resistance F3 of the fall prevention band 38a itself are set to be larger than the folding load F1 of the propeller shaft 12 (F1 <F2, F3). In this case, in this embodiment, the load resistance F3 of the fall prevention band 38a itself is set to be the largest as compared with other loads (F1 <F2 <F3). For example, the bending load F1 of the propeller shaft 12 is set. And may be set to be smaller than the load resistance F2 at the mounting portion 36 of the fall prevention band 38a (F1 <F3 <F2).

  Next, when the bending load F1 of the propeller shaft 12, the load resistance F2 at the mounting portion 36, and the load resistance F3 of the fall prevention belt 38a are set in such a relationship, the vehicle is moved against the obstacle. The experimental results of the frontal collision will be described in detail below. 4A to 4D are side views showing a state in which the propeller shaft is deformed in time series when the vehicle collides front, and FIG. 5 is an enlarged side view of FIG. FIG. 4A shows the normal state of the propeller shaft before the vehicle collides front.

  As the vehicle collides frontally with an obstacle and the movement of the drive source including the engine E and the transmission 16 starts to move backward relative to the vehicle body 11, the load (see the arrow) from the drive source side is increased by the propeller shaft 12 When applied to, a crack occurs in the mount member 23 that supports the front portion of the differential mechanism 20 made of a relatively heavy object. For this reason, as shown in FIG. 4B, when the front portion of the differential mechanism 20 falls from the mount member 23, the connecting portion between the rear end of the propeller shaft 12 and the input shaft 22 of the differential mechanism 20 is different. The hook-type joint 14b is bent at a bending point.

  The centering support 26 that supports the substantially central portion of the propeller shaft 12 breaks from the annular support member formed of an elastic body such as rubber, but the support bracket 30 remains on the vehicle body side to support the propeller shaft 12. Is in a state.

  Subsequently, as shown in FIG. 4C, the connecting portion between the front end of the propeller shaft 12 and the transfer output shaft 18 bends with the hook joint 14a being bent, and at this time, the front end of the propeller shaft 12 is downward. Receive the load.

  This downward load increases as the drive source moves relatively rearward with respect to the vehicle body 11, but in this embodiment, the load resistance F2 and the fall prevention band 38a in the mounting portion 36 of the front fall prevention band 38a are increased. Since the load resistance F3 of the propeller shaft 12 is set to be larger than the bending load F1 of the propeller shaft 12 (F1 <F2, F3), the position where the propeller shaft 12 on the front end side from the fall prevention band 38a is supported by the fall prevention band 38a. Bend down as a break point.

  In other words, since the load resistance F2 at the mounting portion 36 of the fall prevention band 38a on the front side of the folding load F1 of the propeller shaft 12 and the load resistance F3 of the fall prevention band 38a itself are set large, the front fall prevention band 38a. The propeller shaft 12 is supported (constrained) by the front-side fall prevention band 38a until it breaks and / or the mounting portion 36 is damaged. For this reason, due to an increase in the downward load from the drive source side, the propeller shaft 12 bends at a place supported by the front-side fall prevention band 38a.

  As described above, in the present embodiment, the propeller shaft 12 itself is bent at the breakage point where the propeller shaft 12 is supported by the front drop prevention band 38a at the time of the frontal collision of the vehicle, and accordingly, the rear end of the propeller shaft 12 and the differential mechanism 20 side. The degree of bending of the connecting portion by the other hook joint 14b connecting the input shaft 22 can be reduced as compared with the conventional case.

  As a result, in this embodiment, the grounding of the connecting portion (other hook joint 14b) between the input shaft 22 of the differential mechanism 20 and the rear end of the propeller shaft 12 is avoided (FIG. 4D). 5), it is possible to stabilize the shock absorbing performance due to the backward movement of the engine E and the transmission 16 relative to the vehicle body 11.

DESCRIPTION OF SYMBOLS 10 Vehicle power transmission device 11 Vehicle body 12 Propeller shaft 14a Hook joint (first universal joint)
14b Other hook joint (second universal joint)
16 Transmission (drive source)
18 Transfer output shaft (output shaft)
20 Differential mechanism (differential mechanism)
22 Input shaft 26 Center bearing support (support mechanism)
36 Mounting portion 38a Fall prevention band E: Engine (drive source)
F1: Propeller shaft bending load F2: Load resistance at the mounting part of the fall prevention band F3: Load resistance of the fall prevention band itself

Claims (1)

A propeller shaft extending in the front-rear direction of the vehicle body, having a front end connected to the output shaft on the drive source side via the first universal joint, and a rear end connected to the input shaft of the differential mechanism via the second universal joint;
A support mechanism for rotatably supporting the propeller shaft with respect to the vehicle body between the front end and the rear end;
A drop-preventing band that supports the propeller shaft when the propeller shaft falls, having a mounting portion that is attached to the vehicle body across the lower side of the propeller shaft between the front end and the support mechanism;
In a vehicle power transmission device comprising:
When a downward load acting on the front end of the propeller shaft is increased in a state where the propeller shaft is supported by the fall prevention band, the fall prevention band is broken or the attachment of the fall prevention band is performed. The load-proof load and the fall prevention in the attachment part of the fall prevention band so that the propeller shaft on the front end side of the fall prevention band is bent downward from the fall prevention band before the breakage in the part occurs. A power transmission device for a vehicle, wherein a load resistance of the belt itself is set larger than a bending load of the propeller shaft.

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