JP2012159108A - Suspension member structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspension member structure of novel structure, which can efficiently control the pitching vibration, based on torque fluctuation of an engine input to a suspension member, by an active damper, and can decrease the number of required active dampers.SOLUTION: In the suspension member structure 10, the active damper 30 is installed in a position to be a belly of the pitching vibration mode of which a node is a differential 24 of the suspension member 12 on at least either a front or rear side of a vehicle to the differential 24.

Description

  The present invention relates to a suspension member structure that supports a rear wheel suspension arm, a differential gear, and the like in a front engine / rear drive type vehicle, and in particular, can suppress pitching vibration caused by engine torque fluctuations. The present invention relates to a suspension member structure.

  Conventionally, in front engine / rear drive type vehicles, rear suspension members that support a rear wheel suspension arm, a differential gear, and the like have been adopted, and the suspension members are vibration-proof to the vehicle body via member mounts and the like. By being connected, the suspension arm, the differential device and the like are connected to the vehicle body. For example, it is shown in Unexamined-Japanese-Patent No. 2010-95042 (patent document 1).

  By the way, although the vibration of the suspension member is reduced to the vehicle body by a vibration isolator such as a member mount, the transmission of the vibration to the vehicle body can be suppressed by reducing the vibration of the suspension member itself. It is being considered. That is, an active damper as described in Japanese Patent Laid-Open No. 10-231886 (Patent Document 2) is attached to a suspension member to form a suspension member structure, whereby the active damper has a phase opposite to that of the vibration to be controlled. An excitation force is actively applied to the suspension member to cancel and reduce the vibration to be controlled.

  When utilizing such an active damping action by the active damper, the position of the active damper attached to the suspension member is extremely important. In general, the excitation force exerted from the active damper to the suspension member exerts an effective damping action against vibration near the position where the active damper is mounted, so the mounting position of the active damper to the suspension member is It is set near the position where the member mount is located, which is a vibration transmission point from the suspension member to the vehicle body.

  However, since suspension members are generally supported in vibration isolation on the vehicle body via a plurality of member mounts, both end portions in the vehicle width direction are provided with active dampers at respective member mounts. As a result, an increase in vehicle weight, an increase in the number of parts, and the like are likely to be problematic.

  Further, depending on the position of the member mount and the like, there may arise a problem that the active damper itself becomes a new source of vibration and the vibration state deteriorates. In other words, when the position of the active damper attached to the suspension member is not appropriate, the active excitation force exerted from the active damper to the suspension member cannot effectively cancel the vibration to be controlled, and on the contrary, amplifies the vibration. There is a risk that a sufficient vibration control effect cannot be obtained.

JP 2010-95042 A Japanese Patent Laid-Open No. 10-231886

  The present invention has been made in the background of the above-described circumstances, and a solution to the problem is to efficiently suppress the pitching vibration based on the torque fluctuation of the engine input to the suspension member by the active damper. It is another object of the present invention to provide a suspension member structure having a novel structure that can reduce the number of active dampers.

  That is, according to the first aspect of the present invention, the differential device connected to the propeller shaft extending in the vehicle front-rear direction is supported by the suspension member interposed between the suspension arm and the vehicle body, and the suspension In the suspension member structure in which an active damper for applying an active vibration force is attached to the member, the differential member of the suspension member is a node on at least one side of the vehicle front and rear with respect to the differential member. The active damper is attached to a position that becomes an antinode of the pitching vibration mode.

  According to the suspension member structure described in the first aspect, the mounting position of the active damper is set to a position that is at least one of the front and rear sides of the vehicle with respect to the differential device and that is the antinode of the pitching vibration mode. Thus, with a small number of active dampers installed, the generation of a booming noise due to pitching vibration can be efficiently reduced or prevented.

  According to a second aspect of the present invention, in the suspension member structure described in the first aspect, only one active damper is attached to the suspension member on the vehicle rear side of the differential device. It is.

  According to the second aspect, since the active damper is disposed on the rear side of the differential device while avoiding the propeller shaft, it is possible to easily secure the space for disposing the active damper.

  In addition, since the active damper can be disposed at a position closer to the extension line of the propeller shaft (more preferably, on the extension line), adverse effects on the vibration state of the suspension member due to the resonance of the bracket member are suppressed. As a result, the vibration control effect can be obtained more efficiently.

  According to a third aspect of the present invention, in the suspension member structure described in the first or second aspect, the active damper corresponds to a width dimension of the suspension member in a lateral direction of the vehicle at a central portion of the suspension member. It is arranged in an area within 20%.

  According to the third aspect, the active damper is disposed on the suspension member at a substantially central portion in the left-right direction of the vehicle, so that the excitation force exerted from the active damper to the suspension member can be efficiently prevented from pitching vibration. It acts to reduce the pitching vibration and avoid the generation of new vibration due to the action of the excitation force. As a result, the desired vibration damping performance can be effectively obtained with a small number of active dampers.

  According to the present invention, since the active damper is disposed before and after the differential device and at the antinode of the pitching vibration mode of the vibration to be controlled, the target damping is achieved by a small number of active dampers. The vibration effect can be obtained efficiently.

1 is a plan view schematically showing a suspension member structure as a first embodiment of the present invention. FIG. 2 is a left side view schematically showing the suspension member structure shown in FIG. 1.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 show a suspension member structure 10 as one embodiment of the present invention in a state where it is mounted on a vehicle. The suspension member structure 10 includes a suspension member 12 and an active damper system 14 attached to the suspension member 12. In the following description, in principle, the front corresponds to the front of the vehicle in the lower part of FIG. 1 (right side in FIG. 2), and the rear refers to the rear of the vehicle in FIG. The upper part in the middle (left side in FIG. 2) shall be referred to.

  More specifically, the suspension member 12 is a subframe having sufficient rigidity capable of supporting a suspension arm or the like (not shown), and a pair of suspension members 12 extending in the front-rear direction at both ends in the left-right direction (left-right direction in FIG. 1). Body connecting portions 16 and 16 are provided. The front and rear ends of the body connecting portion 16 are vibration-proof connected to the vehicle body by suspension member mounts 18, respectively, and the suspension member 12 is interposed between a suspension arm (not shown) and the vehicle body. Note that the suspension member 12 and the suspension member mount 18 may each be of a known conventional structure, and thus will be described briefly here.

  Further, the pair of body connecting portions 16 and 16 are connected to each other by a front side differential support portion 20 and a rear side differential support portion 22. The front-side differential support portion 20 and the rear-side differential support portion 22 both extend in the left-right direction, and both left and right end portions are fixed to one of the pair of body connecting portions 16, 16 by means such as welding. . The front-side differential support portion 20 supports the front portion of the differential device 24 on the left and right, and the rear-side differential support portion 22 supports the rear portion of the differential device 24 on the rear side.

  The differential device 24 transmits the rotational force of a propeller shaft 28 (described later) exerted by a power unit (not shown) to the rear wheel axle (not shown), and adjusts the amount of rotation of the left and right wheels to improve running stability. Is. The differential 24 is connected to the front-side differential support portion 20 by vibration-proofing on both the left and right sides of the front portion by differential mounts 26 and 26, and the rear portion is protected from the rear-side differential support portion 22 by differential mounts 26 and 26. By vibration coupling, the suspension member 12 supports the vibration isolation. Note that the details of the structure of the differential device 24 and the differential mount 26 are not essential parts of the present invention, and any known conventional structure can be adopted.

  A propeller shaft 28 is connected to the differential device 24. The propeller shaft 28 extends in the vehicle front-rear direction, and transmits the generated force of a power unit (not shown) mounted on the front portion of the vehicle to the rear wheels. The propeller shaft 28 is connected to the differential device 24 by inserting a rear end portion provided with a gear into the differential device 24 and meshing with the gear of the differential device 24.

  On the other hand, an active damper system 14 is attached to the rear differential support portion 22 of the suspension member 12. The active damper system 14 includes an active damper 30 and a control system 32 for controlling driving thereof.

  The active damper 30 is an electromagnetic damper that generates an excitation force in the opposite phase to the vibration to be controlled by displacing a mass member (not shown) by energization from the outside. It has a member and an electromagnetic actuator that drives and displaces the mass member. The active damper 30 is provided with a housing (not shown) that houses the mass member and the electromagnetic actuator. As the active damper 30, for example, one having a known structure as disclosed in Japanese Patent Laid-Open No. 10-231886 can be adopted, and detailed description regarding a specific structure is omitted here. Further, the excitation direction of the active damper 30 is set to a substantially vertical vertical direction (vertical direction in FIG. 2).

  Further, a bracket member 34 is attached to the housing of the active damper 30. The bracket member 34 has a bracket main body 36 which is a highly rigid plate member having a substantially mountain shape when viewed in the front-rear direction. Bolt holes are formed in the outer peripheral portion of the bracket main body 36 at three vertex portions, respectively. Has been. The bracket member 34 is provided with a damper stay 38 as an attachment portion of the active damper 30, and the active damper 30 is fixed to the bracket member 34 by fitting the housing to the damper stay 38. Note that the damper stay 38 may have various structures such as a cylindrical shape that is externally fitted to the housing, and a protrusion or a protruding piece shape that is locked to the housing.

  The bracket member 34 is provided with a sensor stay 40. The sensor stay 40 is a highly rigid member in which the primary natural frequency is set higher than the primary natural frequency of the bracket body 36 and the damper stay 38, and is fixed to the bracket body 36 by welding or screwing. ing. Further, the sensor stay 40 is provided at a portion where the bracket body 36 is fixed to the suspension member 12, in other words, near the bolt hole in the bracket body 36. The sensor stay 40 may be formed integrally with the bracket body 36.

  An acceleration sensor 42 is attached to the sensor stay 40. The acceleration sensor 42 detects a vibration state by detecting the acceleration of the sensor stay 40, and incorporates a transmission means (not shown) that generates a residual signal based on the detection result. The acceleration sensor 42 is fixed and supported to the sensor stay 40 by means such as adhesion and screwing, and the acceleration sensor 42 detects the vibration state of the suspension member 12 transmitted to the sensor stay 40. It has become so. The specific structure of the acceleration sensor 42 is not particularly limited, and a mechanical or optical acceleration sensor can also be adopted. Preferably, however, the change in charge based on the piezoelectric effect and the capacitance A semiconductor-type acceleration sensor that detects acceleration based on a change in the angle is employed.

  Further, the residual signal generated based on the vibration detection result of the acceleration sensor 42 is transmitted to the drive control device 44. The drive control device 44 is a device that controls the electromagnetic actuator of the active damper 30. For example, the drive control device 44 is disposed on a power supply path from a power supply device (not shown) to the electromagnetic actuator, and supplies power to the electromagnetic actuator. Is controlled based on the residual signal to control the excitation force. As described above, the acceleration sensor 42 and the drive control device 44 constitute a control system 32 for controlling the active damper 30. The bracket member 34 attached to the suspension member 12, the active damper 30 fitted to the bracket member 34, and the control system 32 that controls the active damper 30 constitute the active damper system 14 of the present embodiment.

  Such an active damper system 14 is disposed and attached to the suspension member 12 at a predetermined position. That is, the bracket main body 36 of the bracket member 34 constituting the active damper system 14 is superimposed on the rear surface of the rear differential support portion 22 of the suspension member 12 and fixed with bolts. Accordingly, only one active damper 30 is disposed behind the differential device 24 and is attached to the central portion in the left-right direction of the suspension member 12. The active damper system 14 is attached to the suspension member 12 to constitute the suspension member structure 10 of the present embodiment.

  The mounting position of the active damper 30 is set in a region overlapping with the differential device 24 in the longitudinal projection of the vehicle, and preferably the center when the horizontal dimension (width dimension) of the suspension member 12 is 100%. Is set to 20% of the area. As a result, the active damper 30 is disposed on the extension line of the propeller shaft 28 or at a position closer to the extension line of the propeller shaft 28 than the left and right ends of the suspension member 12 in the left-right direction. In the vertical direction, the position of the active damper 30 is not particularly limited, and there is no problem even if the extension line of the propeller shaft 28 or the differential device 24 is moved up and down, but in this embodiment, the propeller shaft 28 are arranged on an extension line.

  In addition, in the mounted state on the vehicle, pitching vibration due to engine torque fluctuation is exerted on the suspension member 12, but the active damper 30 has an antinode in the pitching vibration mode with the differential device 24 as a node in the suspension member 12. It is attached to the position. As described above, the active damper 30 is attached to the antinode of the vibration mode in which the amplitude of the vibration to be controlled is maximum, so that the vibration canceling action (damping action) by the active excitation force of the active damper 30 is achieved. Is effectively exhibited, and pitching vibration caused by torque fluctuation is reduced.

  In addition, since the active damper 30 is disposed in the central portion of the suspension member 12 in the left-right direction, new vibrations are generated in the suspension member 12 due to the mass of the active damper 30 and the bracket member 34 and the vibration force of the active damper 30. Can be prevented. As described above, only one active damper 30 can obtain an effective vibration damping effect against pitching vibration while preventing the deterioration of the mass balance in the left-right direction and the adverse effect on the vibration state due to the vibration.

  Further, the active damper 30 is disposed so as not to deviate from the extension line of the propeller shaft 28 in the vertical direction. As a result, the vibration generated by the resonance of the bracket member 34 and the generated force of the electromagnetic actuator constituting the active damper 30 is suppressed, and an effective damping effect is exhibited.

  Further, since the active damper 30 is attached to the rear side of the vehicle with respect to the differential device 24, the active damper 30 is disposed without being limited by the propeller shaft 28 extending from the differential device 24 to the front side of the vehicle. Space can be easily secured.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, the arrangement position of the active damper 30 may be off the extension line of the propeller shaft 28 in both the vertical direction and the horizontal direction.

  Furthermore, the active damper 30 is desirably disposed behind the differential device 24 for reasons such as ensuring a space for disposition. However, if the active damper 30 is located at the antinode of the pitching vibration mode, the differential may be provided. It may be arranged in front of the device 24.

  Further, the number of active dampers 30 is not necessarily limited to that provided by one, and for example, a total of two active dampers 30, 30 are provided one by one before and after the differential device 24. Also good.

10: Suspension member structure, 12: Suspension member, 24: Differential gear, 28: Propeller shaft, 30: Active damper

Claims (3)

A differential gear connected to a propeller shaft extending in the longitudinal direction of the vehicle is supported by a suspension member interposed between the suspension arm and the vehicle body and exerts an active excitation force on the suspension member. In the suspension member structure to which the active damper is attached,
The suspension member is characterized in that the active damper is attached to at least one side of the differential device at the front and rear sides of the suspension member at a position that becomes an antinode of a pitching vibration mode with the differential device as a node. Structure.   The suspension member structure according to claim 1, wherein only one active damper is attached to the suspension member on a vehicle rear side of the differential device.   The suspension member structure according to claim 1 or 2, wherein the active damper is disposed in a region within 20% of a width dimension of the suspension member in a vehicle left-right direction at a central portion of the suspension member.

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