JP7047789B2 - Bearing support bracket - Google Patents

Description

The present invention relates to a bearing support bracket, and more particularly to a bearing support bracket that supports a bearing member of a power transmission shaft.

A bearing support bracket in which a bearing member that rotatably supports a power transmission shaft is inserted and fixed to a vehicle body is known. For example, the bearing support bracket described in Patent Document 1. The bearing support bracket described in Patent Document 1 includes an annular main body into which a bearing member is inserted, and an arm portion having a pair of fixing portions welded to the arcuate lower end of the main body and fixed to the vehicle body. I have. Further, in the bearing support bracket described in Patent Document 1, two stays are joined by welding between both ends of the arm portion and both sides of the outer peripheral surface of the main body portion, and reinforcing ribs are erected on the outer portion of the stay. There is. This improves the torsional rigidity of the bearing support bracket.

Japanese Unexamined Patent Publication No. 2010-184623

By the way, the bearing support bracket described in Patent Document 1 transmits, for example, a forced force generated by torque fluctuation of a transmission, meshing vibration of a gear, or the like to a vehicle body via a power transmission shaft and a bearing member. In this case, when the resonance frequency of the bearing support bracket, for example, the resonance frequency of the vibration mode in the extension direction of the power transmission shaft, that is, the resonance frequency of the vibration mode in the vehicle left-right direction orthogonal to the vehicle front-rear direction, is close to the frequency of the gear noise due to the forced force of the transmission, the vibration level is increased. It grows larger and generates abnormal noise in the vehicle. In the bearing support bucket rat described in Patent Document 1, a plurality of parts are joined by projection welding, which has a limited number of welding points due to the manufacturing method. Therefore, in the bearing support bracket described in Patent Document 1, the rigidity in the vehicle left-right direction is increased so that the resonance frequency of the bearing support bracket in the vehicle left-right direction and the frequency of the gear noise do not come close to each other, and the vibration mode is set in the vehicle left-right direction. There has been a problem with a large increase in mass when improving the resonance frequency.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bearing support bracket that suppresses an increase in mass and improves rigidity.

The gist of the present invention is a bearing support bracket in which a bearing member that rotatably supports a power transmission shaft is inserted and fixed to a vehicle body, and a cylindrical main body portion into which the bearing member is inserted. And a pair of fixing portions fixed to the vehicle body are integrally molded, and the wall thickness of the portion of the main body portion located at the center between the pair of fixing portions is made relatively larger than the other portions. There is something to do.

According to the bearing support bracket of the present invention, the cylindrical main body portion into which the bearing member is inserted and the pair of fixing portions fixed to the vehicle body are integrally molded, and the pair of the main body portions are integrally formed. The wall thickness of the centrally located portion between the fixed portions is relatively larger than that of the other portions. As a result, deterioration of rigidity due to joining of a plurality of parts can be suppressed as compared with the case where the main body portion and the pair of fixing portions are joined by projection welding or the like. Further, by increasing the wall thickness of the portion of the bearing support bracket where the deformation strain is relatively large, that is, the portion of the main body portion located at the center between the pair of fixed portions, the increase in mass is suppressed. Rigidity can be improved.

It is a schematic diagram which shows a part of the main part of the power transmission shaft to which this invention was applied. It is sectional drawing explaining the bearing member of FIG. 1 and the main part around the bearing member, and is the sectional view II-II of FIG. It is sectional drawing which explains the bearing member of FIG. 1 and the main part around the bearing member, and is the sectional view | FIG. It is sectional drawing explaining the bearing member of FIG. 1 and the main part around the bearing member, and is the sectional view | FIG. It is a figure which shows the relationship between the frequency and the vibration transmission sensitivity level in a bearing support bracket.

The present invention is applied to an engine-driven vehicle having an engine as a driving force source for traveling, a hybrid vehicle having a traveling rotary machine, that is, a driving electric motor in addition to the engine as a driving force source for traveling, an electric vehicle, and the like. .. The present invention can also be applied to an electric vehicle or the like having only an electric motor as a driving force source.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following examples, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of each part are not always drawn accurately.

FIG. 1 is a schematic view showing a main part of a vehicle propeller shaft 10 (hereinafter referred to as a propeller shaft 10), which is a power transmission shaft to which the present invention is applied. FIG. 1 shows a cross-sectional view of parts constituting the propeller shaft 10, specifically, a bearing member 26 described later and a part of the periphery of the bearing member 26. The propeller shaft 10 is a power transmission shaft for transmitting power output from an engine (not shown) to drive wheels of a vehicle (not shown). The propeller shaft 10 is disposed between, for example, a transmission mechanism including a transmission (not shown) connected to the engine and a differential mechanism including a vehicle differential gear device (not shown) connected to the axle of the drive wheel. ing. One end side of the propeller shaft 10, that is, the left side of the drawing in FIG. 1, is the transmission mechanism side, and the other end side of the propeller shaft 10, that is, the right side of the drawing in FIG. 1 is the differential mechanism side. The propeller shaft 10 is rotated around the rotation center axis C.

As shown in FIG. 1, the propeller shaft 10 connects the transmission mechanism and the differential mechanism via the first universal joint 20 and the second universal joint 22 provided at both ends. The propeller shaft 10 is via a shaft-shaped front propeller 24 having one end connected to the first universal joint 20, a center bearing 26 which is a bearing member that rotatably supports the front propeller 24, and a third universal joint 28. A rear propeller 30 having one end connected to the other end of the front propeller 24 is provided. The other end of the rear propeller 30 is connected to the second universal joint 22.

FIG. 2 is a sectional view taken along the line II-II of FIG. 1 and is a sectional view illustrating a main part around the center bearing 26. That is, FIG. 2 is a diagram showing a center bearing 26 and a main part around the center bearing 26 as viewed from the rotation center axis C direction. FIG. 3 is a sectional view taken along line III-III of FIG. 2, which is a sectional view illustrating a main part around the center bearing 26. As shown in FIGS. 2 and 3, the center bearing 26 is fitted concentrically with the rotation center axis C of the propeller shaft 10 on the radial outer side of the propeller shaft 10. The center bearing 26 rotatably supports the propeller shaft 10. As the center bearing 26, for example, a radial ball bearing is used. A cylindrical bearing support bracket 40 for supporting the center bearing 26 is provided on the radial outer side of the center bearing 26. The bearing support bracket 40 is provided concentrically with the rotation center axis C. A cushioning member 42 is provided between the center bearing 26 and the bearing support bracket 40. The upward direction on the paper in FIG. 2 is the upward direction on the vehicle, and the left direction on the paper in FIG. 2 indicates the left direction on the vehicle. Further, the left direction of the paper in FIG. 3 indicates the front direction of the vehicle.

As shown in FIG. 3, the center bearing 26 has a cylindrical inner race 26a fitted to the outer peripheral surface of the propeller shaft 10 and a cylindrical outer race 26b fitted to the inner peripheral portion 42a of the cushioning member 42. A plurality of balls 26c formed in a spherical shape, and a cage 26d that keeps a constant distance between the balls 26c arranged in a line in the circumferential direction between the inner race 44 and the outer race 46. ..

The cushioning member 42 is made of, for example, synthetic rubber vulcanized and bonded to the inner peripheral member 42a and the outer peripheral member 42b, which are cylindrical pressed parts, and the outer peripheral surface of the inner peripheral member 42a and the inner peripheral surface of the outer peripheral member 42b. It is provided with an elastic member 42c and is formed in a substantially annular shape as a whole. The cushioning member 42 is provided between the center bearing 26 and the bearing support bracket 40 in the radial direction, and the outer peripheral member 42b is fitted into the inside of the cylindrical main body portion 40a of the bearing support bracket 40, which will be described later, by press fitting or the like. ing. The inner peripheral member 42a of the cushioning member 42 is formed by bending so as to have a step in the radial direction. The center bearing 26 is positioned in the rotation center axis C direction by the stop member 44 press-fitted into the inner peripheral surface of the inner peripheral member 42a of the cushioning member 42 and the stepped portion.

As shown in FIGS. 2 and 3, the bearing support bracket 40 is symmetrical with respect to the cylindrical main body portion 40a extending in the rotation center axis C direction and the vertical line passing through the center line of the main body portion 40a, that is, the rotation center axis C. It has a pair of left and right fixing portions 40b, which are respectively projected in the horizontal direction from the position. A propeller shaft 10, a center bearing 26, and a cushioning member 42 are internally inserted in the main body portion 40a, and the main body portion 40a supports the center bearing 26 via the cushioning member 42. The fixed portion 40b is formed in a flat plate shape that protrudes outward in the radial direction from the outer peripheral surface of the main body portion 40a and extends in the direction of the rotation center axis C. A bolt insertion hole 50 penetrates the fixing portion 40b. The bolt insertion hole 50 is formed so that the fastening bolt 52 can be inserted, and the bearing support bracket 40 and the vehicle body 54 shown by the alternate long and short dash line in FIG. 2 are fixed by the fastening bolt 52. A spacer 56 through which the fastening bolt 52 is inserted is provided between the vehicle body 54 and the bearing support bracket 40, and for example, the support height of the propeller shaft 10 and the inclination in the vehicle left-right direction are adjusted. As shown in FIG. 2, the fixed portion 40b is provided at a position lower than the rotation center axis C of the main body portion 40a in the vehicle vertical direction, that is, the vehicle height direction.

The bearing support bracket 40 is integrally molded by aluminum extrusion molding in which an aluminum alloy is coldly or hotly extruded using, for example, a die having an extrusion hole having a cross-sectional shape similar to that of the main body portion 40a and the pair of fixing portions 40b.

The outer peripheral surface of the main body portion 40a has an elliptical shape in which the vertical direction of the vehicle is the long axis and the left-right direction of the vehicle is the short axis in the view from the rotation center axis C direction shown in FIG. Specifically, the wall thickness of each of the main body portions 40a on the vehicle vertical direction side is formed to be relatively larger than the wall thickness of each of the main body portions 40a on the vehicle left and right direction side. The wall thickness of the main body portion 40a is formed so as to continuously increase from the left-right direction of the vehicle toward the top-down direction of the vehicle.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 2, and is a diagram illustrating a center bearing 26 and a main part around the center bearing 26. FIG. 4 is a cross-sectional view of the center bearing 26 and the main parts around the center bearing 26 as viewed from an angle different from that of FIG. T1 shown in FIG. 3 and t2 shown in FIG. 4 indicate the wall thickness of the main body portion 40a. That is, t1 shown in FIG. 3 is the wall thickness t1 of the main body portion 40a on the upper side of the vehicle, and indicates the wall thickness t1 of the main body portion 40a of the portion located at the center between the pair of fixed portions 40b. Part A shown in FIG. 2 schematically shows a portion located at the center between the pair of fixed portions 40b. T2 shown in FIG. 4 is the wall thickness t2 of the main body portion 40a on the way from the right side of the vehicle to the upper side of the vehicle, and is the main body portion of the portion located on the right side of the vehicle rather than the central portion between the pair of fixed portions 40b. The wall thickness t2 of 40a is shown. The portion B shown in FIG. 2 schematically shows a portion located on the right side of the vehicle with respect to a portion located at the center between the pair of fixed portions 40b. Further, the portion C shown in FIG. 2 schematically shows a portion of the main body portion 40a located on the right side of the vehicle with respect to the portion B, and specifically, the portion C is located in the vicinity of the main body portion 40a in which the fixed portion 40b protrudes. The part to be used is shown.

As shown in FIGS. 3 and 4, the wall thickness of the main body portion 40a is such that the wall thickness t1 of the main body portion 40a of the portion located at the center between the pair of fixing portions 40b is another portion, for example, the pair of fixing portions 40a. It is formed to be larger than the wall thickness t2 of the main body portion 40a of the portion located on the right side of the vehicle with respect to the center of the space. Further, the wall thickness t1 of the main body portion 40a is larger than the wall thickness of the main body portion 40a of the portion located on the right side of the vehicle more than the portion indicated by the wall thickness t2, specifically, the portion indicated by the point C in FIG. It is formed large.

As shown in FIG. 2, the main body 40a is formed symmetrically with respect to the vertical line or the horizontal line passing through the rotation center axis C. Therefore, the wall thickness t1 of the main body portion 40a is formed so as to be larger than the wall thickness of the main body portion 40a of the other portion located on the left side of the vehicle than the portion located at the center between the pair of fixed portions 40b. .. That is, the wall thickness t1 is formed so as to have the largest wall thickness among the main body portions 40a located above the vehicle above the horizontal line passing through the rotation center axis C. Similarly, the wall thickness of the main body portion 40a of the portion located at the center between the pair of fixed portions 40b on the lower side of the vehicle is the most among the main body portions 40a located below the horizontal line passing through the rotation center axis C. It is formed to have a large wall thickness.

FIG. 5 is a diagram showing the relationship between the frequency f (Hz) and the vibration transmission sensitivity level L (dB). In FIG. 5, the vertical axis indicates the vibration transmission sensitivity level L, and the horizontal axis indicates the frequency f. The vibration transmission sensitivity level L is a vibration level indicating the ease of transmission of vibration. That is, when the vibration transmission sensitivity level L is large, for example, the vibration from the vibration source is easily transmitted, and when the vibration transmission sensitivity level L is small, the vibration from the vibration source is difficult to be transmitted. The thick solid line V shown in FIG. 5 indicates the frequency fv of gear noise due to the forced force of a transmission mechanism (not shown). The solid line d1 shown in FIG. 5 shows the relationship between the frequency f and the vibration transmission sensitivity level L in the bearing support bracket 40 of this embodiment. The alternate long and short dash line dc shown in FIG. 5 shows the relationship between the frequency f and the vibration transmission sensitivity level L in the comparative example. The conventional bearing support bracket is used, in which the bearings are joined to each other and the thickness of the support portion of the center bearing 26 is uniformly formed. Lc shown in FIG. 5 indicates the vibration transmission sensitivity level Lc of the comparative example at the frequency fv, and L1 indicates the vibration transmission sensitivity level L1 of the present embodiment at the frequency fv.

As shown in FIG. 5, in this embodiment, the vibration transmission sensitivity level L at the frequency fv is smaller than that in the comparative example. That is, in this embodiment, the frequency so-called resonance frequency in the bearing support bracket 40 is improved, so that the proximity between the resonance frequency of the bearing support bracket 40 and the frequency fv of the gear noise due to the forced force of the transmission mechanism (not shown) is avoided. Therefore, the vibration transmission sensitivity level L1 is smaller than the vibration transmission sensitivity level Lc of the comparative example. Specifically, the bearing support bracket 40 includes a main body portion 40a and a pair of fixing portions 40b and is integrally molded, so that a plurality of bearing support brackets 40 are compared with a bearing support bracket in which a plurality of parts are joined by, for example, projection welding. Deterioration of rigidity due to joining of parts is suppressed. Further, in the bearing support bracket 40, for example, in a predetermined vibration mode, that is, in a vehicle vibration mode in which the bearing support bracket 40 is deformed in the vehicle left-right direction, the deformation strain of the bearing support bracket 40 in the vehicle left-right direction is compared with other parts. The wall thickness is increased by concentrating on the relatively large portion, that is, the portion of the main body portion 40a located at the center between the pair of fixed portions 40b. Therefore, the bearing support bracket 40 has improved rigidity without reducing the amount of component material used and not accompanied by a large increase in mass. Therefore, in this embodiment, the rigidity of the bearing support bracket 40 is improved as compared with the comparative example shown in FIG. 5, so that the resonance frequency of the bearing support bracket 40 is high, and the comparative example shown in FIG. 5 at the frequency fv. The vibration transmission sensitivity level L is reduced by Ld, which is the difference between the vibration transmission sensitivity level Lc of the above and the vibration transmission sensitivity level L1 of this embodiment.

Returning to FIG. 2, a structural space S is formed between the bearing support bracket 40 and the vehicle body 54. The space S is different in the radial direction of the bearing support bracket 40, for example. Specifically, as shown in FIG. 2, the space S between the outer peripheral surface of the bearing support bracket 10 and the vehicle body 54 is large on the upper side of the vehicle and small on the left and right sides of the vehicle. Since the bearing support bracket 40 is integrally molded by, for example, aluminum extrusion molding, the wall thickness can be freely set, so that the wall thickness on the left and right sides of the vehicle, which has a limitation on the space S, can be easily reduced, and the wall thickness on the left and right sides of the vehicle is relatively small. It is possible to increase the wall thickness on the upper side of the vehicle with a margin.

As described above, according to the bearing support bracket 40 of the present embodiment, the center bearing 26 is integrally molded including the cylindrical main body portion 40a into which the center bearing 26 is inserted and the pair of fixing portions 40b fixed to the vehicle body 54. The wall thickness t1 of the portion of the main body portion 40a located at the center of the pair of fixed portions 40b is relatively larger than the other portions. As a result, deterioration of rigidity due to joining of a plurality of parts can be suppressed as compared with the case where the main body portion 40a and the pair of fixing portions 40b are joined by projection welding or the like. Further, the increase in mass is suppressed by increasing the wall thickness t1 of the portion of the bearing support bracket 40 where the deformation strain is relatively large, that is, the portion of the main body portion 40a located at the center between the pair of fixing portions 40b. Moreover, the rigidity can be improved. Therefore, the bearing support bracket 40 can improve the rigidity at low cost.

Although the preferred embodiments of the present invention have been described in detail with reference to the drawings, the present invention is not limited to this, and the present invention is also carried out in still another embodiment.

For example, in the above-described embodiment, the main body portion 40a is formed symmetrically with respect to the vertical line or the horizontal line passing through the rotation center axis C, but is not necessarily limited to this. That is, the wall thickness of the main body portion 40a may not be formed symmetrically in the vertical direction of the vehicle and the left and right sides of the vehicle, and the shape of the main body portion 40a may be asymmetric with respect to the vertical line or the horizontal line passing through the rotation center axis C. ..

Although the embodiments of the present invention have been described in detail with reference to the drawings, the above is only one embodiment, and although no other examples are given, the present invention can be described by those skilled in the art without departing from the spirit of the present invention. It can be implemented with various changes and improvements based on knowledge.

10: Vehicle propeller shaft (power transmission shaft)
26: Center bearing (bearing member)
40: Bearing support bracket 40a: Main body 40b: Fixed part 54: Body

Claims (1)

A bearing support bracket in which a bearing member that rotatably supports the power transmission shaft is inserted and fixed to the vehicle body.
It is integrally molded including a cylindrical main body portion into which the bearing member is inserted and a pair of fixing portions fixed to the vehicle body.
A bearing support bracket characterized in that the wall thickness of a portion of the main body portion located at the center between the pair of fixed portions is relatively larger than that of the other portions.

Images