JP2020046058A - Upper mount and suspension device including the same - Google Patents

Abstract

To prevent steering torque from increasing as much as possible, while effectively suppressing vibration from being transmitted from a wheel side to a vehicle body side, even in a case where an unsprung weight is large upon mounting an in-wheel motor drive device, etc.SOLUTION: An upper mount 16 comprises: an attachment member 25 to which a vehicle body 11 side of a damper 14 is attached; a first bearing 26 that rotatably supports the body 11 side of a spring 15 disposed outside the damper 14; an elastic member 27 to which the attachment member 25 is fixed on the inside and the first bearing 26 is fixed on the outside; and a connection member 28 that connects the attachment member 25 and the first bearing 26 to the vehicle body 11 via the elastic member 27. The upper mount further comprises a second bearing 30 that rotatably supports a shaft part 18b between the attachment member 25 and the shaft part 18b of one member, which is positioned on the side closer to the vehicle body 11, of a cylinder 17 and a rod 18 constituting the damper 14.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an upper mount and a suspension provided with the upper mount.

  Upper mounts for connecting dampers and springs of an automobile suspension to a vehicle body are roughly classified into an integrated input type and an input separated type. Here, the input integrated type upper mount is a type in which the load transmission path from the spring to the vehicle body and the load transmission path from the damper to the vehicle body are unified. Is a mount in which the transmission path of the load from the spring to the vehicle body and the transmission path of the load from the damper to the vehicle body are separated.

  Specifically, in the input-integrated upper mount, the upper end of the rod constituting the damper is attached to a metal annular member, and the upper end of the coil spring is received by a metal spring seat connected to the annular member. Thus, the load acting not only on the damper but also on the coil spring can be transmitted from the annular member to the vehicle body via the rubber bush (for example, see Patent Document 1). The input-separated type upper mount is configured such that the upper end of the rod constituting the damper is mounted on a metal annular member, and the upper end of the coil spring is received by a metal spring seat. A rubber bush was provided between them, and the point of application of the load from the coil spring to the rubber bush and the point of application of the load from the damper to the rubber bush were separated from the outside and inside of the rubber bush by acting on the coil spring. The load transmission path can be separated from the load transmission path acting on the damper (for example, see Patent Document 2).

JP 2001-116078 A JP 2013-122252 A

  By the way, recently, an in-wheel motor drive device in which a motor is arranged inside a wheel for a wheel and the wheel is driven by this motor is being developed, and introduction into mass-produced products such as an electric vehicle is being studied. ing. When the in-wheel motor driving device is introduced as described above, vibration generated in the front-rear direction of the vehicle body due to driving of the in-wheel motor driving device may be a problem. This vibration is not input to the spring but is transmitted mainly to the vehicle body via the damper. In view of this point, it is preferable to apply an input-separated type upper mount capable of separating the vibration transmitted to the vehicle body into components in each direction, and imparting the rubber bush with vibration reduction characteristics according to the components in each direction. Seem.

  FIG. 4 shows a suspension device 110 that suspends wheels on which the in-wheel motor drive device is mounted. In FIG. 4, reference numeral 11 denotes a vehicle body, reference numeral 12 denotes wheels, reference numeral 13 denotes an in-wheel motor driving device, reference numeral 14 denotes a damper, reference numeral 15 denotes a coil spring, and reference numeral 116 denotes a strut mount as an upper mount. In this suspension device 110, a lower spring seat 23 that receives the lower end of the coil spring 15 is attached to the outer periphery of the cylinder 17 of the damper 14, and the in-wheel motor drive device 13 is connected to the lower end of the cylinder 17. A rod 18 is disposed on the inner periphery of the cylinder 17 so as to be relatively movable in the axial direction and the circumferential direction, and a free piston 19 and a cylinder are disposed between the cylinder 17 and the rod 18 and in the cylinder 17. 17, a plurality of seal portions 20 to 22 are provided. By configuring the suspension device 110 as described above, while suspending the unsprung portions (the cylinder 17, the in-wheel motor drive device 13, the wheels 12, etc.) including the in-wheel motor drive device 13, the vehicle The vibration transmitted to the eleventh side can be effectively suppressed.

  On the other hand, since the in-wheel motor drive device 13 is a heavy object, when the in-wheel motor drive device 13 is mounted on the wheel 12, the moment of inertia around the steered axis increases with an increase in unsprung weight. As a result, a new problem arises in that a large steering torque is required to steer the wheels 12 and the in-wheel motor drive device 13 around the steering axis. Increasing the steering torque is a problem to be avoided because it increases the size and complexity of the steering mechanism, such as increasing the size of the steering operation motor.

  In view of the above circumstances, in this specification, even when the unsprung weight is large, such as when the in-wheel motor drive device is mounted, the steering torque is effectively reduced while effectively suppressing the vibration transmitted from the wheel side to the vehicle body side. The technical problem to be solved is to prevent as much as possible from increasing.

  The above object is achieved by an upper mount according to the present invention. That is, the upper mount includes a mounting member to which the vehicle body side of the damper is mounted, a first bearing for rotatably supporting the vehicle body side of a spring disposed outside the damper, a mounting member fixed to the inside, and a first bearing to the outside. In an upper mount including an elastic member to which a bearing is fixed, and a connecting member for connecting the mounting member and the first bearing to the vehicle body via the elastic member, the dampers are movable in the axial direction with respect to each other, and The cylinder has a cylinder and a rod that can rotate with sliding, and the shaft is rotatable between the mounting part and the shaft of one of the cylinder and rod that is located closer to the vehicle body. It is characterized in that it further comprises a supporting second bearing.

  As described above, in the upper mount according to the present invention, the sliding resistance generated between the cylinder and the rod of the damper at the time of steering is controlled in order to suppress the steering torque that inevitably increases as the unsprung weight increases. I paid attention. For example, in the case where the suspension device 110 has the configuration shown in FIG. 4, in order to enable smooth steering, the rod 18 connected to the vehicle body 11 and the cylinder 17 connected to the wheels 12 are connected. Relative circumferential displacement must be allowed. For this reason, seal portions 20 and 21 are usually provided between the cylinder 17 and the rod 18 so that the cylinder 17 can be axially rotated with respect to the rod 18. However, since sliding resistance between the rotating member (here, the cylinder 17) and the seal portion 20 is unavoidable, a steering torque higher by the resistance is required. The above phenomenon becomes remarkable when the in-wheel motor drive device 13 is mounted on the side of the wheel 12.

  The present invention has been made based on the above findings, and separately from the first bearing that rotatably supports the spring, the shaft of one of the cylinders and rods that constitute the damper is located on the side closer to the vehicle body. A second bearing for rotatably supporting the shaft portion is newly provided between the mounting member and the mounting member. In this way, by rotating and supporting the shaft portion of the damper on the vehicle body side by the second bearing, the cylinder and the rod can be integrally rotated without the cylinder or the rod sliding with the seal portion. Therefore, it is possible to prevent a sliding resistance from being generated between the rod and the cylinder at the time of steering, and even when the in-wheel motor driving device is mounted, the input-separated upper mount structure transmits the vehicle to the vehicle body. It is possible to prevent the steering torque from increasing as much as possible while effectively suppressing the vibration. If an increase in the steering torque can be prevented, it is possible to avoid an increase in the size of the steering operation motor, so that high steering performance can be obtained without changing the steering mechanism.

  In the upper mount according to the present invention, the second bearing may be a bearing having a smaller load capacity than the first bearing.

  While a load is likely to act on the damper as a source of a problematic vibration (for example, vehicle interior noise), the load is not so large as compared with a spring. In view of this point, the second bearing that rotatably supports the shaft portion on the damper side may be a bearing having a smaller load capacity than the first bearing that rotatably supports the spring. According to this configuration, the second bearing can be reduced in size compared to the first bearing, so that a new bearing (second bearing) can be incorporated without largely changing the structure of the existing upper mount. Therefore, the above-described performance of the upper mount can be improved at low cost.

  Further, the upper mount according to the above description, while exhibiting an excellent vibration reduction effect, can prevent an increase in the steering torque due to an increase in unsprung weight as much as possible. , A damper, and a spring.

  In this case, in the suspension device according to the present invention, the damper is an inverted damper in which a rod is disposed on a side far from the vehicle body and a cylinder is disposed on a side close to the vehicle body. May be supported by the second bearing.

  By applying a single-cylinder high-pressure and inverted damper, the unsprung weight can be reduced, and the strut rigidity is high so that the drive response can be improved. Therefore, it is suitable for an in-wheel motor drive device. In addition, an inverted damper requires a seal not only between the rod and cylinder, between the cylinder and the free piston, but also between the cylinder and the cylinder case. There is a concern that the sliding resistance will increase. On the other hand, in the suspension device according to the present invention, the cylinder constituting the inverted damper is provided with the shaft, and the shaft is rotatably supported by the second bearing. The shaft can be rotated. Therefore, according to this configuration, it is possible to avoid an increase in the sliding resistance due to the application of the inverted damper, and to prevent an increase in the steering torque.

  Further, in the suspension device according to the present invention, the in-wheel motor drive device may be connected to the other member of the cylinder and the rod that is located farther from the vehicle body.

  By adopting a structure in which the in-wheel motor driving device is connected to the wheel side of the damper in this way, it is possible to more effectively suppress the vibration generated due to the driving of the in-wheel motor driving device.

  As described above, according to the present invention, even when the unsprung weight is large, such as when the in-wheel motor drive device is mounted, the steering while effectively suppressing the vibration transmitted from the wheel side to the vehicle body side is achieved. An increase in torque can be prevented as much as possible.

It is a sectional view showing the composition of the suspension concerning a first embodiment of the present invention. It is sectional drawing which expands and shows the principal part of the suspension device shown in FIG. It is sectional drawing which expands and shows the principal part of the suspension device which concerns on 2nd embodiment of this invention. It is sectional drawing which shows the structure of the suspension apparatus which concerns on comparison with this invention.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view illustrating a configuration of a main part of a suspension device 10 according to the first embodiment of the present invention. As shown in FIG. 1, the suspension device 10 is a system (specifically, a strut type) in which a wheel 12 is independently suspended and supported on a vehicle body 11. In the present embodiment, an in-wheel motor drive device 13 is used. The mounted wheels 12 can be suspended. Here, the suspension device 10 includes a damper 14, a coil spring 15 disposed coaxially with the damper 14, a predetermined arm member (not shown), and a strut mount as an upper mount for attaching the damper 14 and the coil spring 15 to the vehicle body 11. 16 mainly.

  In the present embodiment, the damper 14 is a single-cylinder high-pressure damper, and has a cylinder 17 and a rod 18 that are mutually movable in the axial direction. Further, between the piston portion 18a of the rod 18 and the cylinder 17, between the opening portion 17a of the cylinder 17 and the rod 18, and between the free piston 19 and the cylinder 17 disposed inside the cylinder 17, respectively. The seal portions 20 to 22 are provided, and the cylinder 17 and the rod 18 are configured to be rotatable with each other while sliding.

  A metal lower spring seat 23 for receiving the lower end 15 a of the coil spring 15 is provided on the outer periphery of the cylinder 17, and a motor connection for connecting to the in-wheel motor driving device 13 is provided on the lower end of the cylinder 17. A member 24 is provided.

  Next, the configuration of the strut mount 16 will be described with reference to FIG.

  The strut mount 16 includes a metal mounting member 25 to which the vehicle body 11 side of the damper 14 is mounted, a first bearing 26 that rotatably supports the coil spring 15 on the vehicle body 11 side, a mounting member 25 fixed inside, and a second mounting member 25 outside. An elastic member 27 made of rubber to which one bearing 26 is fixed, and a metal vehicle body connecting member 28 connecting the mounting member 25 and the first bearing 26 to the vehicle body 11 via the elastic member 27 are provided.

  The first bearing 26 is, for example, a thrust bearing, and includes an upper race 26a, a lower race 26b, and a rolling element 26c. In the present embodiment, the upper race 26a is fixed to the vehicle body connecting member 28 via the elastic member 27, and a metal upper spring seat 29 is fixed below the lower race 26b. The spring seat 29 receives the upper end 15b of the coil spring 15. Thus, the vehicle body 11 side of the coil spring 15 is rotatably supported by the first bearing 26 via the upper spring seat 29, and the load applied to the coil spring 15 is connected to the vehicle body via the first bearing 26 and the elastic member 27. It can be transmitted to member 28.

  The mounting member 25 has a substantially cylindrical shape in the present embodiment, and integrally includes a cylindrical portion 25a fixed inside the elastic member 27 and a bottom portion 25b located at a lower end of the cylindrical portion 25a. The bottom 25b is provided with a hole 25c, into which the upper end of the damper 14, in this embodiment, the upper end 18b of the rod 18, is inserted. Here, a second bearing 30 is provided between the upper end 18 b of the rod 18 and the bottom 25 b of the mounting member 25. In the present embodiment, the second bearing 30 is a radial bearing and includes an outer ring 30a, an inner ring 30b, and a rolling element 30c. Here, the outer ring 30a is fixed to the bottom 25b, and the inner ring 30b is fixed to the outer periphery of the rod 18. Specifically, a shoulder 18c having an axial end face is provided at the upper end 18b of the rod 18, and a male screw 18d is provided on the outer periphery on the upper end side of the shoulder 18c, and the inner race 30b is The inner ring 30b is fixed to the rod 18 by tightening the inner ring 30b with the nut 32 via the collar 31 in a state where the inner ring 30b is in contact with the shoulder 18c. Accordingly, the vehicle body 11 side of the damper 14 is rotatably supported by the second bearing 30, and the load acting on the damper 14 is applied to the vehicle body connecting member 28 via the second bearing 30, the mounting member 25, and the elastic member 27. Can be communicated.

  According to the strut mount 16 and the suspension device 10 including the strut mount 16, the transmission path of the load applied to the coil spring 15 can be separated from the transmission path of the load applied to the damper 14. While suspending the unsprung portion including the wheel motor driving device 13 (in this embodiment, the cylinder 17, the in-wheel motor driving device 13, and the wheels 12), it is possible to effectively suppress the vibration transmitted from the unsprung portion to the vehicle body 11. It becomes possible.

  Further, in the strut mount 16 having the above-described configuration, apart from the first bearing 26 that rotatably supports the coil spring 15, one of the cylinder 17 and the rod 18 that constitute the damper 14, which is located closer to the vehicle body 11, The embodiment is characterized in that a second bearing 30 for rotatably supporting the upper end portion 18b is newly provided between the upper end portion 18b as a shaft portion of the rod 18 and the mounting member 25. In this way, by rotating and supporting the shaft portion (upper end portion 18b) of the damper 14 on the vehicle body 11 side by the second bearing 30, the rod 18 and the cylinder 17 can be rotated integrally with the shaft. Therefore, it is possible to prevent the sliding resistance from being generated between the rod 18 and the cylinder 17 when the wheel 12 is steered, and even when the in-wheel motor driving device 13 is applied (see FIG. 1). In addition, in the strut mount 16 of the input-separated type, it is possible to effectively suppress the vibration transmitted to the vehicle body 11 and to prevent the steering torque from increasing as much as possible. If an increase in the steering torque can be prevented, it is possible to avoid an increase in the size of the steering operation motor, so that high steering performance can be obtained without changing the steering mechanism.

  In the strut mount 16 according to the present embodiment, a bearing having a smaller load capacity than the first bearing 26 is used as the second bearing 30. According to this configuration, the second bearing 30 can be made smaller in size than the first bearing 26 (see FIG. 2), so that a new bearing (the second bearing 30) can be used without largely changing the structure of the existing strut mount 16. ) Can be incorporated. Therefore, the above-described performance of the strut mount 16 can be improved at low cost.

  Further, in the suspension device 10 according to the present embodiment, a single-cylinder high-pressure damper 14 is applied. For example, when a double-cylinder damper is used, bubbles generated by cavitation may clog the orifice and obstruct the flow of oil in the cylinder 17. In particular, when used in an environment in which the temperature changes drastically, such as in an automobile, the generation of air bubbles is inevitable, so that the damping performance is likely to be reduced. On the other hand, if the single-tube high-pressure damper 14 does not have the above-described problem of bubbles, the damper 14 can be suitably applied to the suspension system 10 for an automobile.

  As described above, the first embodiment of the present invention has been described. However, the upper mount and the suspension device according to the present invention can adopt a configuration other than the above without departing from the gist thereof.

  For example, in the above-described embodiment, the case where the damper 14 in which the rod 18 is disposed on the side close to the vehicle body 11 and the cylinder 17 is disposed on the side far from the vehicle body 11 is applied as the suspension device 10 is exemplified, Of course, other forms are also possible. FIG. 3 is a cross-sectional view showing a configuration of a main part of a suspension device 40 according to an example (a second embodiment of the present invention). As shown in FIG. 3, the suspension device 40 according to the present embodiment is different from the suspension device 10 according to the first embodiment mainly in the configuration of the damper 41. Specifically, this damper 41 has a cylinder 42 and a rod 43 that can move and rotate in the axial direction with respect to each other, and arranges the cylinder 42 on the side closer to the vehicle body 11 and the rod 43 on the side farther from the vehicle body 11. This is a so-called inverted damper that is arranged. In this case, the opening 42a of the cylinder 42 is located below (the side farther from the vehicle body 11), and the closing part 42b is located above (the side closer to the vehicle body 11). That is, the rod 43 protrudes downward from the cylinder 42.

  Further, in the present embodiment, the damper 41 further has a cylinder case 44 that houses the cylinder 42. In this case, the cylinder case 44 has an upper opening 44a and a lower opening 44b below. A hole 44c is formed in the closing portion 44b, and a lower end 43b of the rod 43 projecting downward is fixed to the hole 44c by, for example, screw fitting. This allows the cylinder 42 to move in the axial direction with respect to the rod 43 and the cylinder case 44. Further, seal portions 46 to 48 are provided between the piston 43a of the rod 43 and the cylinder 42, between the rod 43 and the opening 42a of the cylinder 42, and between the free piston 45 and the cylinder 42 in the cylinder 42, respectively. At the same time, seal portions 49 and 50 are provided between the outer periphery of the opening 42a of the cylinder 42 and the cylinder case 44, and between the cylinder 42 and the outer periphery of the opening 44a of the cylinder case 44, respectively. This allows the cylinder 42 to rotate with respect to the rod 43 and the cylinder case 44 while sliding.

  Further, a metal lower spring seat 23 for receiving the lower end portion 15a of the coil spring 15 is provided on the outer periphery of the cylinder case 44, and an in-wheel motor driving device is provided at the lower end thereof as in the first embodiment. A motor connecting member 24 (see FIG. 1) that connects to the motor 13 is provided.

  Further, a shaft portion 51 extending upward is provided integrally or separately in the closing portion 42b of the cylinder 42. The shaft portion 51 is inserted into a hole 25c of the mounting member 25 constituting the strut mount 16, and the inner ring 30b of the second bearing 30 is fixed to the outer periphery of the shaft portion 51. Specifically, the shaft portion 51 is provided with a shoulder portion 51a having an axial end surface, and a male screw portion 51b located on the distal end side of the shoulder portion 51a. The inner ring 30b is fixed to the shaft 51 by tightening the inner ring 30b with the nut 32 via the collar 31 in a state where the inner ring 30b is in contact with the shoulder 51a. Thereby, the vehicle body 11 side of the damper 41 is rotatably supported by the second bearing 30, and the load acting on the damper 41 is applied to the vehicle body connecting member 28 via the second bearing 30, the mounting member 25, and the elastic member 27. Can be communicated. Note that the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description will be omitted.

  As described above, in the strut mount 16 according to the present embodiment, apart from the first bearing 26 that rotatably supports the coil spring 15, the cylinder 42 and the rod 43 that constitute the damper 41 Since the second bearing 30 for rotatably supporting the shaft portion 51 is provided between the shaft portion 51 of 42 and the mounting member 25, the cylinder 42 or the rod 43 is formed between the seal portions 46, 47, 49, and 50. The axis of rotation of the cylinder 42 and the rod 43 can be integrally rotated without sliding. Therefore, it is possible to prevent a sliding resistance from being generated between the cylinder 42 and the rod 43 when the wheel 12 is steered, and even when the in-wheel motor driving device 13 is applied (see FIG. 1). In addition, it is possible to prevent the transmission torque from increasing as much as possible while effectively suppressing the vibration transmitted to the vehicle body 11 by the input mount type upper mount structure.

  Further, in the suspension device 10 according to the present embodiment, as a single-cylinder high-pressure damper, an inverted damper 41 in which the rod 43 is arranged on the side far from the vehicle body 11 and the cylinder 42 is arranged on the side close to the vehicle body 11 is used. Applied. By arranging the damper 41 of this form between the strut mount 16 and the in-wheel motor drive device 13, the unsprung weight can be reduced, and the strut rigidity can be increased to improve the drive response. In addition, by adopting the inverted damper 41, not only between the rod 43 and the cylinder 42 and between the cylinder 42 and the free piston 45, but also between the cylinder 42 and the cylinder case 44, the sealing portions 46 to 50, there is a concern that the sliding resistance may increase. However, according to the suspension device 40 according to the present embodiment, the above-mentioned sliding resistance is not likely to occur. The damper 41 can be applied.

  In the above embodiment, a case where a thrust ball bearing is applied as the first bearing 26 that rotatably supports the coil spring 15 on the vehicle body 11 side has been described as an example, but other thrust bearings can also be applied. is there. Also, the second bearing 30 that rotatably supports the damper 14, 41 on the vehicle body 11 side is not limited to the radial ball bearing, and other types of radial bearings (such as a sliding bearing and a fluid bearing) can be applied. . Of course, depending on the magnitude of the load acting on the dampers 14 and 41, a thrust bearing may be used instead of the radial bearing.

  In the above embodiment, the case where the motor connecting member 24 is provided on the cylinder 17 or the cylinder case 44 of the damper 14 and the damper 14 is directly connected to the in-wheel motor driving device 13 has been exemplified. Can be adopted. For example, although not shown, it is also possible to connect the dampers 14, 41 to predetermined arm members constituting the suspension devices 10, 40.

  Further, in the above embodiment, the suspension devices 10 and 40 for suspending the wheel 12 on which the in-wheel motor drive device 13 is mounted have been exemplified. However, of course, the present invention suspends the wheel 12 without the in-wheel motor drive device 13. The case is also applicable.

10, 40 Suspension device 11 Body 12 Wheel 13 In-wheel motor drive 14, 41 Damper 15 Coil spring 16 Strut mount 17, 42 Cylinder 18, 43 Rod 18a Piston portion 18c, 51a Shoulder portion 18d, 51b Screw portion 19, 45 Free Pistons 20 to 22, 46 to 50 Seal part 24 Motor connecting member 25 Mounting member 26 First bearing 27 Elastic member 28 Body connecting member 30 Second bearing 31 Collar 32 Nut 44 Cylinder case 51 Shaft part 110 Suspension device (configuration for comparison) )
116 Strut mount (comparison configuration)

Claims (5)

A mounting member to which the vehicle body side of the damper is mounted,
A first bearing that rotatably supports the vehicle body side of a spring disposed outside the damper,
An elastic member to which the mounting member is fixed inside, and the first bearing is fixed to the outside;
An upper mount including: a connecting member that connects the mounting member and the first bearing to the vehicle body via the elastic member;
The damper has a cylinder and a rod that are movable in the axial direction with respect to each other, and are rotatable with sliding relative to each other,
It further comprises a second bearing rotatably supporting the shaft portion between the mounting portion and the shaft portion of one of the cylinder and the rod, which is located closer to the vehicle body than the body. Yes, upper mount.   The upper mount according to claim 1, wherein the second bearing is a bearing having a smaller load capacity than the first bearing.   A suspension device comprising the upper mount according to claim 1, the damper, and the spring.   The damper is an inverted damper in which the rod is disposed on a side far from the vehicle body and the cylinder is disposed on a side close to the vehicle body, and the shaft provided on the cylinder is the second bearing. 4. The suspension of claim 3, which is supported.   The suspension device according to claim 3, wherein an in-wheel motor drive device is connected to the other of the cylinder and the rod that is located farther from the vehicle body.

Images