JP6936587B2 - Bearing device for wheels - Google Patents

Description

The present invention relates to a wheel bearing device.

Conventionally, a wheel bearing device that rotatably supports a wheel has been known (see Patent Document 1). In such a wheel bearing device, an outer member is fixed to the vehicle body. Further, an inner member is arranged inside the outer member, and a plurality of rolling elements are interposed between both rolling surfaces of the outer member and the inner member. In this way, the wheel bearing device constitutes a rolling bearing structure and makes the wheels attached to the inner members rotatable.

By the way, in such a wheel bearing device, when a large and shocking external force is applied, an indentation may be formed on the rolling surface of the rolling element. Specifically, when a large and shocking external force is applied, such as when a wheel rides on a curb, the rolling element rises up the rolling surface, causing so-called edge load and indentation on the rolling surface. There was (see FIG. 13). Therefore, in order to prevent the occurrence of edge load, a wheel bearing device having an arc-shaped shoulder on the rolling surface and a wheel bearing device having an inclined shoulder on the rolling surface have been proposed (). See Patent Document 2 and Patent Document 3). However, even in these wheel bearing devices, if a larger and more shocking external force than expected is applied, indentations may be formed on the rolling surface. As a result, abnormal noise due to indentation may occur or the bearing life may be shortened. Therefore, indentation on the transfer surface without increasing the load capacity of the wheel bearing device, that is, increasing the size of the wheel bearing device. There was a limit to effectively suppressing the outbreak. It should be noted that increasing the size of the wheel bearing device means an increase in unsprung mass in the vehicle, which leads to a decrease in steering stability and fuel consumption, which is not preferable.

JP-A-2015-224655 Japanese Unexamined Patent Publication No. 2011-64263 Japanese Unexamined Patent Publication No. 2011-241938

Provided is a wheel bearing device in which an indentation is not formed on a rolling surface even when a large and shocking external force is applied through the wheel without increasing the size of the wheel bearing device. As a result, the present invention provides a bearing device for wheels that does not generate abnormal noise due to indentation or shorten the bearing life.

The first invention is
An outer member with an outer rolling surface formed on the inner circumference,
An inner member with an inner rolling surface formed on the outer circumference,
A plurality of rolling elements interposed between the outer member and both rolling surfaces of the inner member are provided.
In a wheel bearing device in which a plurality of bolt insertion holes are provided in a vehicle body mounting flange formed on the outer member and the vehicle body is attached to the vehicle body by knuckle bolts inserted into the respective bolt insertion holes.
The vehicle body mounting flange is displaceable with respect to the knuckle bolt.

The second invention is the wheel bearing device according to the first invention.
All the bolt insertion holes have an oval shape extending from the lower front side to the upper rear side.

The third invention is the wheel bearing device according to the first invention.
Of the bolt insertion holes, the first bolt insertion hole has a round circular shape.
The other bolt insertion hole has an oval shape extending in the arc direction centered on the first bolt insertion hole.

The fourth invention is the wheel bearing device according to any one of the first to third inventions.
An elastic member is interposed in the bolt insertion hole.

As the effect of the present invention, the following effects are exhibited.

In the wheel bearing device according to the first invention, the vehicle body mounting flange is freely displaceable with respect to the knuckle bolt. According to such a wheel bearing device, when a large and shocking external force is applied such as when a wheel rides on a curb, the mounting position of the vehicle body mounting flange is displaced, so that the contact pressure between the rolling element and the rolling surface increases. Can be prevented. Therefore, even when a large and shocking external force is applied through the wheels, it is possible to prevent indentation on the rolling surface. As a result, abnormal noise due to indentation is not generated, and it is possible to prevent a decrease in bearing life.

In the wheel bearing device according to the second invention, all the bolt insertion holes have an oval shape extending from the lower front side to the upper rear side. According to such a wheel bearing device, a large and shocking external force is applied not in the vertical direction or substantially the vertical direction when absorbing vibration from the road surface, but from a direction in which it is difficult to apply in a normal running state such as when a wheel rides on a rim stone. Only when this happens, the mounting position will be displaced. Therefore, in the normal running state, the bearing rigidity does not decrease, so that the steering stability is not affected.

In the wheel bearing device according to the third invention, the first bolt insertion hole among the bolt insertion holes has a round circular shape. Further, the other bolt insertion holes have an oval shape extending in the arc direction centered on the first bolt insertion hole. According to such a wheel bearing device, a large and shocking external force is applied not in the vertical direction or substantially the vertical direction when absorbing vibration from the road surface, but from a direction in which it is difficult to apply in a normal running state such as when a wheel rides on a rim stone. Only when this happens, the mounting position will be displaced. Therefore, in the normal running state, the bearing rigidity does not decrease, so that the steering stability is not affected.

In the wheel bearing device according to the fourth invention, an elastic member is interposed in the bolt insertion hole. According to such a wheel bearing device, when a large and shocking external force is applied, this external force can be buffered. Further, when the external force is released, the vehicle body mounting flange can be returned to the normal mounting position.

The perspective view which shows the bearing device for a wheel. FIG. 5 is a cross-sectional view showing the structure of a wheel bearing device. FIG. 5 is a cross-sectional view showing a partial structure of a wheel bearing device. FIG. 5 is a cross-sectional view showing a partial structure of a wheel bearing device. The cross-sectional view which shows the mounting structure of the bearing device for a wheel. Sectional drawing which shows the fastening part of a knuckle bolt. The figure which shows the body body mounting flange of the wheel bearing device which is 1st Embodiment. The figure which shows the situation which the vehicle body mounting flange is displaced from the normal mounting position. The figure which shows the situation which the vehicle body mounting flange returns to the normal mounting position. The figure which shows the body body mounting flange of the wheel bearing device which is 2nd Embodiment. The figure which shows the situation which the vehicle body mounting flange is displaced from the normal mounting position. The figure which shows the situation which the vehicle body mounting flange returns to the normal mounting position. The figure which shows the situation where a wheel rides on a curb and an indentation is made on the rolling surface.

First, the wheel bearing device 1 according to the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a perspective view showing a wheel bearing device 1. FIG. 2 is a cross-sectional view showing the structure of the wheel bearing device 1. 3 and 4 are cross-sectional views showing a partial structure of the wheel bearing device 1.

The wheel bearing device 1 rotatably supports the wheels. The wheel bearing device 1 includes an outer member 2, an inner member 3, a rolling element 4, an inner side sealing member 5, and an outer side sealing member 6. In the present specification, the "inner side" represents the vehicle body side of the wheel bearing device 1 when attached to the vehicle body, and the "outer side" refers to the wheel bearing device 1 when attached to the vehicle body. Represents the wheel side.

The outer member 2 constitutes an outer ring portion of the rolling bearing structure. The outer member 2 is made of medium-high carbon steel such as S53C. A sealing surface 2a is formed at the inner end of the outer member 2. Further, a sealing surface 2b is formed at the outer end of the outer member 2. Further, two outer rolling surfaces 2c and 2d are formed on the inner circumference of the outer member 2. The outer rolling surface 2c faces the inner rolling surface 3c, which will be described later. The outer rolling surface 2d faces the inner rolling surface 3d, which will be described later. The outer rolling surfaces 2c and 2d are induction hardened and have a surface hardness in the range of 58 to 64 HRC. In addition, a vehicle body mounting flange 2e is integrally formed on the outer periphery of the outer member 2. The vehicle body mounting flange 2e is provided with a plurality of bolt insertion holes 2f.

The inner member 3 constitutes an inner ring portion of the rolling bearing structure. The inner member 3 is composed of a hub ring 31 and an inner ring 32.

The hub wheel 31 is made of medium-high carbon steel such as S53C. The hub ring 31 is formed with a small diameter step portion 3a from the inner side end portion to the axial central portion. The small diameter step portion 3a refers to a portion where the outer diameter of the hub ring 31 is reduced, and the outer peripheral surface thereof has a cylindrical shape centered on the rotation axis A. Further, the hub ring 31 is formed with a universal joint mounting hole 3b penetrating from the inner side end portion to the outer side end portion thereof. The universal joint mounting hole 3b refers to a through hole provided in the center of the hub ring 31, and a part of the inner peripheral surface thereof has a concave-convex shape (spline hole) in which concave portions and convex portions are alternately arranged. Further, an inner rolling surface 3c is formed on the outer periphery of the hub ring 31. The inner rolling surface 3c faces the outer rolling surface 2c described above. The hub ring 31 is induction hardened from the small diameter step portion 3a through the inner rolling surface 3c to the seal land portion (composed of the shaft surface portion 3e, the curved surface portion 3f, and the side surface portion 3g, which will be described later), and has a surface hardness. Is in the range of 58 to 64 HRC. In addition, a wheel mounting flange 3h is integrally formed on the outer periphery of the hub wheel 31. The wheel mounting flange 3h is provided with a plurality of bolt press-fitting holes 3i at equal intervals on a concentric circle centered on the rotation shaft A, and hub bolts 33 are press-fitted into the respective bolt press-fitting holes 3i.

The inner ring 32 is made of high carbon chrome bearing steel such as SUJ2. A sealing surface 3k is formed on the outer circumference of the inner ring 32. Further, an inner rolling surface 3d is formed on the outer circumference of the inner ring 32. The inner ring 32 is fitted (outerly fitted) to the small diameter step portion 3a of the hub ring 31 to form an inner rolling surface 3d on the outer circumference of the hub ring 31. The inner rolling surface 3d faces the above-mentioned inner rolling surface 2d. The inner ring 32 is so-called stub-quenched and has a core portion in the range of 58 to 64 HRC.

The rolling element 4 constitutes a rolling portion of the rolling bearing structure. The rolling element 4 is made of high carbon chrome bearing steel such as SUJ2. In the rolling element row 4R on the inner side, a plurality of rolling elements 4 are arranged in an annular shape by a cage. Each rolling element 4 is rotatably interposed between the outer rolling surface 2d of the outer member 2 and the inner rolling surface 3d of the inner member 3. On the other hand, in the rolling element row 4R on the outer side, a plurality of rolling elements 4 are arranged in an annular shape by a cage. Each rolling element 4 is rotatably interposed between the outer rolling surface 2c of the outer member 2 and the inner rolling surface 3c of the inner member 3. The rolling element 4 is so-called stub-quenched and has a range of 62 to 67 HRC up to the core.

The inner side sealing member 5 seals the inner side end portion of the annular space S formed between the outer member 2 and the inner member 3. However, the inner side sealing member 5 has various specifications and is not limited to the specifications of the present application.

The inner side sealing member 5 includes a slinger 51. The slinger 51 is fitted (outerly fitted) to the sealing surface 3k of the inner ring 32. The slinger 51 is made of, for example, a stainless steel plate such as SUS430 or SUS304, or a cold-rolled steel plate such as SPCC. The slinger 51 has a shape in which an annular steel plate is deformed by press working and the axial cross section is bent into a substantially L shape. As a result, the slinger 51 is formed with a cylindrical fitting portion 51a and a disc-shaped side plate portion 51b extending from the end portion thereof toward the outer member 2.

The inner side sealing member 5 includes a sealing ring 52. The seal ring 52 is fitted (innerly fitted) to the fitting portion 2a of the outer member 2. The seal ring 52 is composed of a core metal 53 and a seal rubber 54. The core metal 53 is made of, for example, a stainless steel plate such as SUS430 or SUS304, or a cold-rolled steel plate such as SPCC. The core metal 53 has a shape in which an annular steel plate is deformed by press working and the axial cross section is bent into a substantially L shape. As a result, the core metal 53 is formed with a cylindrical fitting portion 53a and a disc-shaped side plate portion 53b extending from the end portion toward the inner ring 32. A seal rubber 54, which is an elastic body, is vulcanized and adhered to the fitting portion 53a and the side plate portion 53b.

The seal rubber 54 is a synthetic rubber such as NBR (acrylonitrile-butadiene rubber), HNBR (hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene rubber), ACM (polyacrylic rubber), FKM (fluorine rubber), or silicon rubber. It is composed of. The tip of the seal lip 54a formed on the seal rubber 54 is in contact with the fitting portion 51a of the slinger 51. Further, the tip portions of the seal lips 54b and 54c are in contact with the side plate portion 51b of the slinger 51. In this way, the inner side sealing member 5 prevents foreign matter such as muddy water and dust from entering the annular space S, and prevents grease from leaking from the annular space S.

The outer side sealing member 6 seals the outer side end portion of the annular space S formed between the outer member 2 and the inner member 3. However, the outer side seal member 6 has various specifications and is not limited to the specifications of the present application.

The outer side seal member 6 is fitted (innerly fitted) to the fitting portion 2b of the outer member 2. The outer side sealing member 6 is composed of a core metal 62 and a sealing rubber 63. The core metal 62 is made of, for example, a stainless steel plate such as SUS430 or SUS304, or a cold-rolled steel plate such as SPCC. The core metal 62 has a shape in which an annular steel plate is deformed by press working and the axial cross section is bent into a substantially L shape. As a result, the core metal 62 is formed with a cylindrical fitting portion 62a and a disc-shaped side plate portion 62b extending from the end portion toward the hub ring 31. A seal rubber 63, which is an elastic body, is vulcanized and adhered to the fitting portion 62a and the side plate portion 62b.

The seal rubber 63 is a synthetic rubber such as NBR (acrylonitrile-butadiene rubber), HNBR (hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene rubber), ACM (polyacrylic rubber), FKM (fluorine rubber), or silicon rubber. It is composed of. The tip of the seal lip 63a formed on the seal rubber 63 is in contact with the shaft surface portion 3e of the hub ring 31. Further, the tip portion of the seal lip 63b is in contact with the curved surface portion 3f of the hub ring 31. Further, the tip portion of the seal lip 63c is in contact with the side surface portion 3g of the hub ring 31. In this way, the outer side sealing member 6 prevents foreign matter such as muddy water and dust from entering the annular space S, and prevents grease from leaking from the annular space S.

Next, a structure for attaching the wheel bearing device 1 to the vehicle body will be described with reference to FIGS. 5 and 6. FIG. 5 is a cross-sectional view showing a mounting structure of the wheel bearing device 1. FIG. 6 is a cross-sectional view showing a fastening portion of the knuckle bolt 34.

The wheel bearing device 1 is mounted on the vehicle body using the pilot 2g and the vehicle body mounting flange 2e. Specifically, in the wheel bearing device 1, the knuckle is in a state where the cylindrical pilot 2g is fitted into the round circle of the knuckle N and the end face of the vehicle body mounting flange 2e is in contact with the end face of the knuckle N. It is attached via a bolt 34. At this time, the knuckle bolt 34 is inserted into the bolt insertion hole 2f of the vehicle body mounting flange 2e from the outer side and screwed into the screw hole of the knuckle N.

As shown in FIG. 6A, the knuckle bolt 34 has a large-diameter shaft portion 34c formed between the head portion 34a and the screw portion 34b. The length dimension Dx of the large-diameter shaft portion 34c is slightly larger than the thickness dimension Dz of the vehicle body mounting flange 2e. This is done so that the mounting position of the vehicle body mounting flange 2e can be displaced freely. Further, as shown in FIG. 6B, the knuckle bolt 34 may be screwed into the screw hole of the knuckle N in a state of being inserted into the sleeve 35. In this case, the length dimension Dy of the sleeve 35 should be slightly larger than the thickness dimension Dz of the vehicle body mounting flange 2e. This is also because the mounting position of the vehicle body mounting flange 2e can be displaced freely.

Next, the vehicle body mounting flange 2e of the wheel bearing device 1 according to the first embodiment will be described with reference to FIG. 7. FIG. 7 is a diagram showing a vehicle body mounting flange 2e of the wheel bearing device 1 according to the first embodiment. This corresponds to the view seen from arrow B in FIG. Further, the arrow F in the figure indicates the forward direction of the vehicle body. A straight line that is parallel to the direction in which gravity acts and intersects the rotation axis A is defined as the vertical direction line V. Further, a straight line that is perpendicular to the vertical direction line V and intersects the rotation axis A is defined as the front-back direction line H. Below the front-rear direction line H is the so-called road surface side, and above the front-rear direction line H is the so-called counter-road surface side.

The vehicle body mounting flange 2e of the wheel bearing device 1 has a substantially triangular shape. Each corner portion is provided with a bolt insertion hole 2f that penetrates from the inner end surface to the outer end surface. That is, the vehicle body mounting flange 2e is provided with three bolt insertion holes 2f that penetrate each of the body mounting flanges 2e. In the following, of the three bolt insertion holes 2f, the bolt insertion hole 2f provided slightly in front of the vertical direction line V and above the vertical direction line V is referred to as the "first bolt insertion hole 21f", and the bolt provided below the front side. The insertion hole 2f is referred to as a "second bolt insertion hole 22f", and the bolt insertion hole 2f provided on the lower rear side is referred to as a "third bolt insertion hole 23f".

The first bolt insertion hole 21f has an oval shape extending in a predetermined direction. To be described in detail, the first bolt insertion hole 21f passes through the center point P1 of the knuckle bolt 34 inserted into the first bolt insertion hole 21f, and tends to have a predetermined angle α with respect to the front-rear direction line H. It has an elongated oval shape. The first bolt insertion hole 21f has an oval shape represented by two parallel lines and two arc lines, and the relative distance between the two parallel lines is the diameter of the large diameter shaft portion 34c of the knuckle bolt 34 or the sleeve. The value is slightly larger than the diameter of 35. Also, the diameters of the two arc lines are slightly larger.

The second bolt insertion hole 22f has an oval shape extending in a predetermined direction. To be described in detail, the second bolt insertion hole 22f passes through the center point P2 of the knuckle bolt 34 inserted into the second bolt insertion hole 22f, and tends to have a predetermined angle α with respect to the front-rear direction line H. It has an elongated oval shape. The second bolt insertion hole 22f has an oval shape represented by two parallel lines and two arc lines, and the relative distance between the two parallel lines is the diameter of the large diameter shaft portion 34c of the knuckle bolt 34 or the sleeve. The value is slightly larger than the diameter of 35. Also, the diameters of the two arc lines are slightly larger.

The third bolt insertion hole 23f has an oval shape extending in a predetermined direction. To be described in detail, the third bolt insertion hole 23f passes through the center point P3 of the knuckle bolt 34 inserted into the third bolt insertion hole 23f, and tends to have a predetermined angle α with respect to the front-rear direction line H. It has an elongated oval shape. The third bolt insertion hole 23f has an oval shape represented by two parallel lines and two arc lines, and the relative distance between the two parallel lines is the diameter of the large diameter shaft portion 34c of the knuckle bolt 34 or the sleeve. The value is slightly larger than the diameter of 35. Also, the diameters of the two arc lines are slightly larger.

Here, the angle α is the bearing rigidity and the rolling surface (outer rolling surface 2c / 2d, inner rolling surface 3c) in a normal running state (running state in which a large and shocking external force is not applied via the wheels). It is a value obtained by analyzing all cases where the indentation of the rolling element 4 is attached to 3d), and is in the range of 15 ° to 45 ° from the lower front side to the upper rear side. However, the specific value is not limited. Further, the bush 36, which is an elastic member so as to wrap the knuckle bolt 34 inserted in each bolt insertion hole 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion hole 23f). Is intervened.

The bush 36 is a synthetic rubber such as NBR (acrylonitrile-butadiene rubber), HNBR (hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene rubber), ACM (polyacrylic rubber), FKM (fluorine rubber), or silicon rubber. It is composed of. Alternatively, it may be composed of a resin such as ABS or PVC. The bush 36 has a substantially crescent shape, and has an outer peripheral surface of the large-diameter shaft portion 34c of each knuckle bolt 34 and each bolt insertion hole 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion). A predetermined elastic force is applied to the inner peripheral surface of the hole 23f). Alternatively, the bush 36 applies a predetermined elastic force to the outer peripheral surface of each sleeve 35 and the inner peripheral surface of each bolt insertion hole 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion hole 23f). Is exerting. The value of the elastic force is also a value obtained by analyzing all cases in which the rolling surface (outer rolling surface 2c / 2d, inner rolling surface 3c / 3d) is indented by the rolling element 4.

Next, a situation in which the mounting position of the vehicle body mounting flange 2e is displaced will be described with reference to FIGS. 8 and 9. FIG. 8 is a diagram showing a situation in which the vehicle body mounting flange 2e is displaced from the normal mounting position. FIG. 9 is a diagram showing a situation in which the vehicle body mounting flange 2e returns to the normal mounting position. The arrows F in these figures also indicate the forward direction of the vehicle body. As in FIG. 7, a straight line that is parallel to the direction in which gravity acts and intersects the rotation axis A is defined as the vertical direction line V. Further, a straight line that is perpendicular to the vertical direction line V and intersects the rotation axis A is defined as the front-back direction line H. Below the front-rear direction line H is the so-called road surface side, and above the front-rear direction line H is the so-called counter-road surface side.

First, the mounting position of the vehicle body mounting flange 2e in a normal running state (a running state in which a large and shocking external force is not applied via the wheels) will be described. As shown in FIG. 8A, in such a state, the vehicle body mounting flange 2e is in the normal mounting position. The normal mounting position is the direction in which the knuckle bolt 34 inserted into the first bolt insertion hole 21f is in the longitudinal direction of the first bolt insertion hole 21f (the direction in which the angle α is a predetermined angle with respect to the front-rear direction line H). It passes through a position that is offset to the center or slightly to the rear. Further, the knuckle bolt 34 inserted through the second bolt insertion hole 22f is located in the central portion or slightly rear side of the second bolt insertion hole 22f in the longitudinal direction (direction at which a predetermined angle α is formed with respect to the front-rear direction line H). It passes through a position that is misaligned. Then, the knuckle bolt 34 inserted through the third bolt insertion hole 23f is located in the central portion or slightly rear side of the third bolt insertion hole 23f in the longitudinal direction (direction at which a predetermined angle α is formed with respect to the front-rear direction line H). It passes through a position that is misaligned. The mounting position of the vehicle body mounting flange 2e determined in this way is the normal mounting position.

Next, the mounting position of the vehicle body mounting flange 2e in a state where a large and impactful external force is applied via the wheels will be described. As shown in FIG. 8B, in such a state, the vehicle body mounting flange 2e is in the mounting position when retracted. The mounting position at the time of retracting is the first bolt insertion hole 21f because the vehicle body mounting flange 2e is displaced in the direction of a predetermined angle α with respect to the front-rear direction line H according to the magnitude of the external force (see arrow M). The knuckle bolt 34 inserted into the knuckle bolt 34 has moved to the front side of the position of the knuckle bolt 34 in the normal mounting position. Further, the knuckle bolt 34 inserted through the second bolt insertion hole 22f is also moved to the front side of the position of the knuckle bolt 34 in the normal mounting position. The knuckle bolt 34 inserted through the third bolt insertion hole 23f has also moved to the front side of the position of the knuckle bolt 34 in the normal mounting position. The mounting position of the vehicle body mounting flange 2e determined in this way is the mounting position at the time of evacuation.

As described above, in the wheel bearing device 1, the vehicle body mounting flange 2e is freely displaceable with respect to the knuckle bolt 34. According to such a wheel bearing device, when a large and shocking external force is applied such as when a wheel rides on a rim stone, the mounting position of the vehicle body mounting flange 2e is displaced (from the normal mounting position to the retracted mounting position). Since it is displaced), it is possible to prevent the contact pressure between the rolling element 4 and the rolling surface (outer rolling surface 2c / 2d, inner rolling surface 3c / 3d) from increasing. Therefore, even when a large and shocking external force is applied through the wheels, it is possible to prevent indentations on the rolling surface (outer rolling surface 2c / 2d, inner rolling surface 3c / 3d). can. As a result, abnormal noise due to indentation is not generated, and it is possible to prevent a decrease in bearing life.

Specifically, in the bearing device 1 for this wheel, all the bolt insertion holes 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion hole 23f) are from the lower front side to the upper rear side. It is an oval shape extending to. Therefore, when a large and shocking external force is applied through the wheels, the mounting position is displaced in a predetermined direction (see arrow M in FIG. 8B). According to the wheel bearing device 1, it is not in the vertical direction or substantially the vertical direction when absorbing vibration from the road surface, but in a direction (component force in the front-rear direction) that is difficult to be applied in a normal running state such as when a wheel rides on a rim stone. The mounting position will be displaced only when a large and shocking external force is applied from the larger direction). Therefore, in the normal running state, the bearing rigidity does not decrease, so that the steering stability is not affected.

In addition, in the bearing device 1 for this wheel, the bush 36 is interposed in each bolt insertion hole 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion hole 23f). The bush 36 buffers an external force. Further, as shown in FIGS. 9A and 9B, the vehicle body mounting flange 2e returns to the normal mounting position when the external force is released (see arrow M). This is due to the elastic force of the bush 36. However, it may be realized by another urging member such as a spring instead of the bush 36.

As described above, in the bearing device 1 for this wheel, the elastic member (bush 36) is interposed in the bolt insertion hole 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion hole 23f). ing. According to the wheel bearing device 1, when a large and shocking external force is applied, this external force can be buffered. Further, when the external force is released, the vehicle body mounting flange 2e can be returned to the normal mounting position (see arrow M in FIG. 9B).

Next, the vehicle body mounting flange 2e of the wheel bearing device 1 according to the second embodiment will be described with reference to FIG. FIG. 10 is a diagram showing a vehicle body mounting flange 2e of the wheel bearing device 1 according to the second embodiment. This corresponds to the view seen from arrow B in FIG. Further, the arrow F in the figure indicates the forward direction of the vehicle body. A straight line that is parallel to the direction in which gravity acts and intersects the rotation axis A is defined as the vertical direction line V. Further, a straight line that is perpendicular to the vertical direction line V and intersects the rotation axis A is defined as the front-back direction line H. Below the front-rear direction line H is the so-called road surface side, and above the front-rear direction line H is the so-called counter-road surface side.

The vehicle body mounting flange 2e of the wheel bearing device 1 has a substantially triangular shape. Each corner portion is provided with a bolt insertion hole 2f that penetrates from the inner end surface to the outer end surface. That is, the vehicle body mounting flange 2e is provided with three bolt insertion holes 2f that penetrate each of the body mounting flanges 2e. In the following, of the three bolt insertion holes 2f, the bolt insertion hole 2f provided slightly in front of the vertical direction line V and above the vertical direction line V is referred to as the "first bolt insertion hole 21f", and the bolt provided below the front side. The insertion hole 2f is referred to as a "second bolt insertion hole 22f", and the bolt insertion hole 2f provided on the lower rear side is referred to as a "third bolt insertion hole 23f".

The first bolt insertion hole 21f has a round circular shape. More specifically, the first bolt insertion hole 21f has a circular shape centered on the center point P1 of the knuckle bolt 34 inserted into the first bolt insertion hole 21f. The diameter of the first bolt insertion hole 21f is slightly larger than the diameter of the large-diameter shaft portion 34c of the knuckle bolt 34 or the diameter of the sleeve 35.

The second bolt insertion hole 22f has an oval shape extending in the arc direction centered on the first bolt insertion hole 21f. More specifically, the second bolt insertion hole 22f passes through the center point P2 of the knuckle bolt 34 inserted into the second bolt insertion hole 22f, and has a radius D2 about the first bolt insertion hole 21f in the arc direction. It has an oval shape that extends to. The second bolt insertion hole 22f has an oval shape represented by two parallel lines and two arc lines, and the relative distance between the two parallel lines is the diameter of the large diameter shaft portion 34c of the knuckle bolt 34 or the sleeve. The value is slightly larger than the diameter of 35. Also, the diameters of the two arc lines are slightly larger.

The third bolt insertion hole 23f has an oval shape extending in the arc direction centered on the first bolt insertion hole 21f. More specifically, the third bolt insertion hole 23f passes through the center point P3 of the knuckle bolt 34 inserted into the third bolt insertion hole 23f, and has a radius D3 centered on the first bolt insertion hole 21f in the arc direction. It has an oval shape that extends to. The third bolt insertion hole 23f has an oval shape represented by two parallel lines and two arc lines, and the relative distance between the two parallel lines is the diameter of the large diameter shaft portion 34c of the knuckle bolt 34 or the sleeve. The value is slightly larger than the diameter of 35. Also, the diameters of the two arc lines are slightly larger.

Here, in the wheel bearing device 1 of the second embodiment, the positions of the respective bolt insertion holes 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion hole 23f) are important. Become. These positions are the bearing rigidity and the rolling surface (outer rolling surface 2c / 2d, inner rolling surface 3c / 3d) in the normal running state (running state in which a large and shocking external force is not applied through the wheels). ) Is indented by the rolling element 4, and is required by analyzing all cases. Further, the bush 36, which is an elastic member so as to wrap the knuckle bolt 34 inserted in each bolt insertion hole 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion hole 23f). Is intervened.

The bush 36 is a synthetic rubber such as NBR (acrylonitrile-butadiene rubber), HNBR (hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene rubber), ACM (polyacrylic rubber), FKM (fluorine rubber), or silicon rubber. It is composed of. Alternatively, it may be composed of a resin such as ABS or PVC. The bush 36 has a substantially crescent shape, and has an outer peripheral surface of the large-diameter shaft portion 34c of each knuckle bolt 34 and each bolt insertion hole 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion). A predetermined elastic force is applied to the inner peripheral surface of the hole 23f). Alternatively, the bush 36 applies a predetermined elastic force to the outer peripheral surface of each sleeve 35 and the inner peripheral surface of each bolt insertion hole 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion hole 23f). Is exerting. The value of the elastic force is also a value obtained by analyzing all cases in which the rolling surface (outer rolling surface 2c / 2d, inner rolling surface 3c / 3d) is indented by the rolling element 4.

Next, a situation in which the mounting position of the vehicle body mounting flange 2e is displaced will be described with reference to FIGS. 11 and 12. FIG. 11 is a diagram showing a situation in which the vehicle body mounting flange 2e is displaced from the normal mounting position. FIG. 12 is a diagram showing a situation in which the vehicle body mounting flange 2e returns to the normal mounting position. The arrows F in these figures also indicate the forward direction of the vehicle body. As in FIG. 10, a straight line that is parallel to the direction in which gravity acts and intersects the rotation axis A is defined as the vertical direction line V. Further, a straight line that is perpendicular to the vertical direction line V and intersects the rotation axis A is defined as the front-back direction line H. Below the front-rear direction line H is the so-called road surface side, and above the front-rear direction line H is the so-called counter-road surface side.

First, the mounting position of the vehicle body mounting flange 2e in a normal running state (a running state in which a large and shocking external force is not applied via the wheels) will be described. As shown in FIG. 11A, in such a state, the vehicle body mounting flange 2e is in the normal mounting position. The normal mounting position is the central portion of the knuckle bolt 34 inserted into the second bolt insertion hole 22f in the longitudinal direction of the second bolt insertion hole 22f (the arc direction centered on the first bolt insertion hole 21f). Or it passes through a position that is slightly displaced to the rear side. Further, the knuckle bolt 34 inserted through the third bolt insertion hole 23f is displaced to the central portion or slightly rearward in the longitudinal direction of the third bolt insertion hole 23f (the arc direction centered on the first bolt insertion hole 21f). It is passing through the position. The mounting position of the vehicle body mounting flange 2e determined in this way is the normal mounting position.

Next, the mounting position of the vehicle body mounting flange 2e in a state where a large and impactful external force is applied via the wheels will be described. As shown in FIG. 11B, in such a state, the vehicle body mounting flange 2e is in the mounting position when retracted. The mounting position at the time of retracting is that the vehicle body mounting flange 2e is displaced in the arc direction centered on the first bolt insertion hole 21f according to the magnitude of the external force (see arrow M), so that the vehicle body mounting flange 2e is inserted into the second bolt insertion hole 22f. The knuckle bolt 34 is moved to the front side of the position of the knuckle bolt 34 in the normal mounting position. Further, the knuckle bolt 34 inserted through the third bolt insertion hole 23f is also moved to the front side of the position of the knuckle bolt 34 in the normal mounting position. The mounting position of the vehicle body mounting flange 2e determined in this way is the mounting position at the time of evacuation.

As described above, in the wheel bearing device 1, the vehicle body mounting flange 2e is freely displaceable with respect to the knuckle bolt 34. According to such a wheel bearing device, when a large and shocking external force is applied such as when a wheel rides on a rim stone, the mounting position of the vehicle body mounting flange 2e is displaced (from the normal mounting position to the retracted mounting position). Since it is displaced), it is possible to prevent the contact pressure between the rolling element 4 and the rolling surface (outer rolling surface 2c / 2d, inner rolling surface 3c / 3d) from increasing. Therefore, even when a large and shocking external force is applied through the wheels, it is possible to prevent indentations on the rolling surface (outer rolling surface 2c / 2d, inner rolling surface 3c / 3d). can. As a result, abnormal noise due to indentation is not generated, and it is possible to prevent a decrease in bearing life.

Specifically, in the wheel bearing device 1, the first bolt insertion hole 21f of the bolt insertion holes 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion hole 23f) is round. It has a circular shape. Further, the other bolt insertion holes 2f (second bolt insertion hole 22f, third bolt insertion hole 23f) have an oval shape extending in the arc direction centered on the first bolt insertion hole 21f. Therefore, when a large and shocking external force is applied through the wheels, the mounting position is displaced in the arc direction (see arrow M in FIG. 11B). According to such a wheel bearing device, a large and shocking external force is applied not in the vertical direction or substantially the vertical direction when absorbing vibration from the road surface, but from a direction in which it is difficult to apply in a normal running state such as when a wheel rides on a rim stone. Only when this happens, the mounting position will be displaced. Therefore, in the normal running state, the bearing rigidity does not decrease, so that the steering stability is not affected.

In addition, in the bearing device 1 for this wheel, the bush 36 is interposed in each bolt insertion hole 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion hole 23f). The bush 36 buffers an external force. Further, as shown in FIGS. 12A and 12B, the vehicle body mounting flange 2e returns to the normal mounting position when the external force is released (see arrow M). This is due to the elastic force of the bush 36. However, it may be realized by another urging member such as a spring instead of the bush 36.

As described above, in the bearing device 1 for this wheel, the elastic member (bush 36) is interposed in the bolt insertion hole 2f (first bolt insertion hole 21f, second bolt insertion hole 22f, third bolt insertion hole 23f). ing. According to the wheel bearing device 1, when a large and shocking external force is applied, this external force can be buffered. Further, when the external force is released, the vehicle body mounting flange 2e can be returned to the normal mounting position (see arrow M in FIG. 12B).

The wheel bearing device 1 in the present application is an inner member composed of an outer member 2 having a vehicle body mounting flange 2e and an inner member 3 in which one inner ring 32 is fitted to a hub wheel 31. It has a third-generation structure with member rotation specifications, but it is not limited to this. For example, a third outer member rotation specification composed of an outer member formed as a hub ring and an inner member in which one inner ring is fitted to a support shaft having a vehicle body mounting flange. It may have a generational structure. Further, a second generation structure of an inner member rotation specification, which is composed of an outer member having a vehicle body mounting flange and a pair of inner members, and the pair of inner members are fitted to the outer circumference of the hub wheel. It may be. Further, a hub wheel and a universal joint are connected as an inner member, and the outer member having a vehicle body mounting flange and an inner member which is a fitting body of the hub wheel and the universal joint are formed. It may have a four-generation structure.

The present invention is not limited to each embodiment, but is merely an example, and it goes without saying that the present invention can be further implemented in various forms without departing from the gist of the present invention. The scope of the invention is indicated by the description of the scope of claims, and further includes the equal meaning described in the scope of claims, and all modifications within the scope.

1 Wheel bearing device 2 Outer member 2c Outer rolling surface 2d Outer rolling surface 2e Body mounting flange 2f Bolt insertion hole 21f First bolt insertion hole 22f Second bolt insertion hole 23f Third bolt insertion hole 3 Inner member 31 Hub wheel 32 Inner ring 33 Hub bolt 34 Knuckle bolt 34a Head 34b Threaded part 34c Large diameter shaft part 35 Sleeve 36 Elastic member (bush)
3c Inner rolling surface 3d Inner rolling surface 4 Rolling element 5 Inner side sealing member 6 Outer side sealing member

Claims (4)

An outer member with an outer rolling surface formed on the inner circumference,
An inner member with an inner rolling surface formed on the outer circumference,
A plurality of rolling elements interposed between the outer member and both rolling surfaces of the inner member are provided.
In a wheel bearing device in which a plurality of bolt insertion holes are provided in a vehicle body mounting flange formed on the outer member and the vehicle body is attached to the vehicle body by a knuckle bolt inserted into each of the bolt insertion holes.
A wheel bearing device characterized in that the bolt insertion hole is displaceable with respect to the knuckle bolt. The wheel bearing device according to claim 1, wherein all the bolt insertion holes have an oval shape extending from the lower front side in the forward direction of the vehicle body to the upper rear side in the forward direction of the vehicle body. Of the bolt insertion holes, the first bolt insertion hole has a round circular shape.
The wheel bearing device according to claim 1, wherein the other bolt insertion hole has an oval shape extending in an arc direction centered on the first bolt insertion hole. The wheel bearing device according to any one of claims 1 to 3, wherein an elastic member is interposed in the bolt insertion hole.

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