JP5211017B2 - Vehicle suspension system - Google Patents

Description

  The present invention relates to a vehicle suspension device, and in particular, a first damping force generation device that generates a damping force between a sprung member and an unsprung member and an approaching or separating operation of the sprung member and the unsprung member, and The present invention relates to a vehicle suspension apparatus in which a second damping force generator is arranged in series.

  This type of vehicle suspension device is described, for example, in Patent Document 1 below. In the vehicle suspension device described in Patent Document 1 below, the first damping force generator includes a motor assembled to the sprung member, a ball screw nut (rotating member), and a ball screw shaft (linear motion member). And a ball screw mechanism (converting mechanism) that converts the rotational motion of the ball screw nut accompanying the rotational output of the motor to linear motion of the ball screw shaft. For this reason, in the first damping force generator described in Patent Document 1 below, the motor can linearly move (up and down) the linear motion member in accordance with the vibration of the sprung member and the unsprung member. In addition, it is possible to apply not only a damping force but also a propulsive force that actively moves the sprung member and the unsprung member relative to the approaching or separating operation of the sprung member and the unsprung member.

  Further, in the vehicle suspension device described in Patent Document 1 below, the second damping force generator is assembled to the unsprung member and extends in the vertical direction (axial direction), and a ball screw. And a shaft member that is connected to the ball screw shaft of the mechanism and is disposed in the cylinder member and is movable relative to the cylinder member in the vertical direction. The second damping force generator includes an inner cylinder fixed to the shaft member, an outer cylinder arranged on the outer periphery of the inner cylinder and fixed to the cylinder member, and the outer cylinder and the inner cylinder elastically. A pair of upper and lower rubber elastic bodies connected to each other, a pair of upper and lower liquid chambers filled with hydraulic fluid below the upper rubber elastic body and above the lower rubber elastic body, and a flow of hydraulic fluid And a communication passage that communicates with each liquid chamber.

  In the vehicle suspension device described in Patent Document 1 below, when the outer cylinder and the inner cylinder (cylinder member and shaft member) move relative to each other in the vertical direction, each rubber elastic body is elastically deformed, and the volume in each liquid chamber Changes. Thus, when the hydraulic fluid in one liquid chamber flows into the other liquid chamber through the communication passage, the flow of the hydraulic fluid is restricted by the communication passage, and the relative movement in the vertical direction of the outer cylinder and the inner cylinder is limited. Resistance (damping force) acts. For this reason, in the second damping force generator described in Patent Document 1 below, a damping force is applied to the approaching or separating operation of the sprung member and the unsprung member by elastic deformation of each rubber elastic body. In particular, it is possible to attenuate high-frequency vibrations (for example, vibrations of 10 Hz or more) that are difficult to effectively attenuate with the first damping force generator. In addition, since the second damping force generation device includes both liquid chambers and both rubber elastic bodies, the second damping force generation device includes a second damping force as compared with the configuration including the damper device and the coil spring. The force generator can be configured compactly and simply.

JP 2008-247054 A

  By the way, in the vehicle suspension apparatus described in Patent Document 1, the second damping force generator generates a damping force using hydraulic fluid (oil or the like), and therefore, due to temperature change and deterioration of the hydraulic fluid. The viscosity characteristics of the hydraulic fluid are likely to change, making it difficult to obtain the desired damping force. In the second damping force generator described above, the elastic deformation of each rubber elastic body and the liquid flow through the communication path between both liquid chambers are linked, and the relative speed between the cylinder member and the shaft member is If it exceeds a predetermined value (value determined by the viscosity of the hydraulic fluid, the size of the communication path, etc.), the fluid flow between the two fluid chambers will not be able to follow the relative speed, and the elastic deformation of each rubber elastic body will also be It becomes impossible to follow the relative speed, and a desired damping force corresponding to the relative speed cannot be obtained. Therefore, in the vehicle suspension device described in Patent Document 1, the second damping force generator has a compact and simple configuration, but the damping force sequentially required by the second damping force generator can be obtained. There is a risk of not.

  The present invention has been made to cope with the above-described problems, and an object of the present invention is to provide a damping force that is sequentially required by the second damping force generation device while the second damping force generation device is compact and simple. It is an object of the present invention to provide a vehicle suspension device that is easy to obtain.

To achieve the above object, the present invention provides a first damping force generator that generates a damping force between the sprung member and the unsprung member with respect to the approaching or separating operation of the sprung member and the unsprung member. And the second damping force generating device is arranged in series, and the first damping force generating device has a motor assembled to the sprung member, a rotating member, and a linear motion member, and serves as a rotational output of the motor. And a conversion mechanism for converting the rotational motion of the rotating member into the linear motion of the linear motion member, and the second damping force generator is assembled to the unsprung member and extends in the vertical direction. A shaft member that is connected to the linear member of the conversion mechanism and is disposed in the cylinder member and is movable relative to the cylinder member in the vertical direction, and between the shaft member and the cylinder member Previously assembled in series In a vehicle suspension apparatus comprising an upper viscoelastic body (rubber, urethane, etc.) and a lower viscoelastic body (rubber, urethane, etc.) that are elastically deformed by relative movement of the cylinder member and the shaft member in the vertical direction, the upper viscoelastic body is provided. A pair of upper and lower air chambers defined by the cylinder member and the shaft member and communicating with each other through the communication path are formed above the elastic body and below the lower viscoelastic body, and the first damping force is generated. The outer periphery of the device and the second damping force generator has an air chamber filled with pressurized air and air supply / discharge means capable of supplying and discharging pressurized air to and from the air chamber. An air spring device that applies a spring force to the member is provided, and a communication means is provided for communicating the air chamber of the air spring device with any one of the air chambers. In particular there is a feature has been.

  In the vehicle suspension device according to the present invention, the motor is controlled to rotate by the electronic control unit according to the vibration of the sprung member and the unsprung member during vehicle travel, and the rotational motion of the rotating member is linearly driven by the conversion mechanism. It is converted into a linear motion (vertical motion) of the member. At this time, the upper viscoelastic body and the lower viscoelastic body can be elastically deformed according to the vertical movement (relative movement) of the cylinder member and the shaft member. For this reason, a damping force can be obtained by the first damping force generator by rotating the motor, and a damping force can be obtained by the second damping force generator by elastic deformation of the upper viscoelastic body and the lower viscoelastic body. The vibration of the sprung member and the unsprung member can be suppressed.

  Here, when the vibration of the sprung member and the unsprung member is a low-frequency vibration (for example, a vibration of 5 Hz or less), the motor (first damping force generator) is sufficiently sufficient for the low-frequency vibration described above. The first damping force generator can obtain a necessary and sufficient damping force (resistance force). However, at this time, the cylinder member moves up and down together with the shaft member, and the upper viscoelastic body and the lower viscoelastic body do not elastically deform, so that no damping force can be obtained by the second damping force generator.

  On the other hand, when the vibrations of the sprung member and the unsprung member are high-frequency vibrations (for example, vibrations of 10 Hz or more), it becomes difficult for the motor to follow the above-described high-frequency vibrations. Necessary and sufficient damping force cannot be obtained with the device. However, at this time, the cylinder member relatively moves in the vertical direction with respect to the shaft member, and the upper viscoelastic body and the lower viscoelastic body are elastically deformed, and a damping force can be obtained by the second damping force generator. .

  Further, when the cylinder member and the shaft member relatively move in the vertical direction (when the vibrations of the sprung member and the unsprung member are high frequency vibrations), the elastic deformation of the upper viscoelastic body and the lower viscoelastic body The volume in the air chamber changes. For this reason, at this time, the pressurized air (high pressure air) in each air chamber flows through the communication passage, and a resistance force (attenuating force) acts on the relative movement between the cylinder member and the shaft member, thereby causing the second attenuation. Further damping force can be obtained with the force generator.

  By the way, in the vehicle suspension apparatus according to the present invention, since the second damping force generating device generates the damping force using air, there is no need to consider the temperature change and deterioration of the air, and the desired damping is achieved. Easy to get power. In addition, since the working fluid linked to the elastic deformation of the upper viscoelastic body and the lower viscoelastic body is air and has a lower viscosity than when a working fluid (for example, oil) is employed as the working fluid, Even if the relative speed of the shaft member is increased, the flow of air (working fluid) can sufficiently follow the relative speed between the two air chambers. Furthermore, since air is a compressible fluid that can be compressed in each air chamber, if the air flow between the two air chambers cannot follow the relative velocity, the air in each air chamber. Since the elastic deformation of the upper viscoelastic body and the lower viscoelastic body is ensured by the compression of, a desired damping force according to the relative speed is obtained also in this case. Therefore, it is possible to easily obtain the damping force sequentially required by the second damping force generator.

  In addition, the second damping force generation device includes both air chambers and both viscoelastic bodies, and the second damping force generation device is not provided with a damper device and a coil spring. Therefore, the second damping force generation device (cylinder member) can be configured in a compact and simple manner as compared with the configuration in which the second damping force generation device includes the damper device and the coil spring. Therefore, the axial length and the radial length of the suspension device can be reduced, and the weight and cost of the suspension device can be reduced.

Also, before SL on the outer circumference of the first damping-force generating device and the second damping force generating device, pressurized air is sealed the air chamber and the supply and discharge possible air feeding and discharging means pressurized air to the air chamber And an air spring device for applying a spring force to the sprung member and the unsprung member, and communicating means for communicating the air chamber of the air spring device with any one of the air chambers. Is provided. For this reason , even if a minute air leak occurs in each air chamber, the air supply / exhaust means supplies pressurized air to the air chamber, so that the pressurized air enters the air chamber from the air chamber through the communicating means. Can be supplied. Therefore, it is possible to always keep the internal pressure of the air chamber and each air chamber at a desired pressure.

  In this case, for example, if communication means (communication hole, communication pipe, etc.) with a small hole diameter are provided, the flow rate of the pressurized air flowing through the communication means becomes small when the relative speed between the cylinder member and the shaft member is high. Thus, a difference is easily generated between the internal pressures of the two air chambers. On the other hand, when the relative speed between the cylinder member and the shaft member is small, the flow rate of the pressurized air flowing through the communicating means is large, and it is difficult for a difference between the internal pressures of both air chambers to occur. For this reason, when the relative speed between the cylinder member and the shaft member is large, a large damping force can be generated, and when the relative speed between the cylinder member and the shaft member is small, a small damping force can be generated. Therefore, the damping force generated by the second damping force generator can be easily changed by the communicating means in accordance with the relative speed between the cylinder member and the shaft member.

  In carrying out the present invention, a cylindrical portion that extends in the vertical direction to the outer periphery of the cylinder member is connected to a support member that is assembled to the sprung member and supports the motor. It is also possible to provide a bearing between the cylinder member. In this case, when a lateral force (external force in the axial direction) acts on the lower arm that is a part of the unsprung member, this lateral force is transmitted from the cylinder member to the bearing and is mainly received by the bearing. The And since this bearing is provided between the cylinder member assembled | attached to the unsprung member and the cylinder part of the supporting member extended to an up-down direction to the outer periphery of the cylinder member, a lower arm The vertical distance from the bearing to the bearing is short. Therefore, the rotational moment (torsional moment) generated in the member (bearing) that receives the lateral force can be reduced, and the reliability of the member that receives the lateral force can be increased.

  In carrying out the present invention, the motor is elastically connected to the sprung member via an upper support, and the upper support has an annular elastic portion, and the diameter of the inner hole of the elastic portion is It is also possible to make it smaller than the outer diameter of the motor. In this case, since the elastic part of the upper support is not penetrated by the motor as described in, for example, Patent Document 1, it is possible to increase the volume of the elastic part of the upper support compared to Patent Document 1. Thus, it is possible to reduce the spring constant (spring characteristic) of the elastic portion of the upper support. Therefore, by reducing the spring constant of the elastic part of the upper support, it is possible to improve the riding comfort against high-frequency vibration (vibration that feels rugged), reduce noise and vibration, and reduce the unsprung member's vibration. It is possible to mitigate the impact caused by pushing up.

1 is a front cross-sectional view illustrating a first embodiment of a vehicle suspension device according to the present invention. It is front sectional drawing which expanded the lower side of FIG. It is front sectional drawing which showed 2nd Embodiment of the suspension apparatus for vehicles in this invention. It is front sectional drawing which showed 3rd Embodiment of the suspension apparatus for vehicles in this invention.

  Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 shows a first embodiment of a vehicle suspension apparatus according to the present invention. This suspension apparatus SP is provided for each of the front, rear, left and right wheels of the vehicle, and is provided between the mount HA and the lower arm LA. Is provided. The mount HA and the vehicle body supported by the mount HA are the sprung member SU, and the lower arm LA and the wheel connected to the lower arm LA via a knuckle are the unsprung members SD.

  As shown in FIG. 1, the suspension device SP includes a first damping force generation device A1 and a second damping force generation device that generate a damping force with respect to the approaching or separating operation of the sprung member SU and the unsprung member SD. A2, an air spring device A3 that applies a spring force to the sprung member SU and the unsprung member SD, and a lateral force guide mechanism A4 that receives a lateral force (an external force in the direction perpendicular to the axis) that acts on the lower arm LA. ing. The first damping force generation device A1 and the second damping force generation device A2 are arranged in series, and the first damping force generation device A1 is provided above (on the sprung member SU side), and the second damping force generation device A1 is provided. The force generator A2 is provided below (the unsprung member SD side).

  As shown in FIG. 1, the first damping force generator A1 includes a holder 10 assembled to the mount portion HA, a motor 20 supported by the holder 10, and a rotational output of the motor 20 in a straight line. A ball screw mechanism 30 for converting into motion and a ball spline mechanism 40 provided in the holder 10 are provided, and a damping force is generated by rotational driving of the motor 20.

  The holder 10 is elastically connected to the sprung member SU via the upper support 11 and extends in the vertical direction (axial direction). The holder 10 has a holder main body 10 a that houses the motor 20 and the ball screw mechanism 30, and a small-diameter cylindrical portion 10 b that houses the ball spline mechanism 40 below. The upper cylinder member 70 (cylinder part) in the lateral force guide mechanism A4 is connected to the lower end part of the holder body 10a.

  The upper support 11 has an upper metal part 11a, a lower metal part 11b, and an elastic part 11c. The upper metal part 11a is formed in an annular shape, and is fixed to the mount part HA using three bolts BT. The lower metal fitting 11b is formed in an annular shape and is fixed to the upper end portion of the holder body 10a. A cap 12 is assembled in the inner hole 11b1 of the lower metal fitting 11b. With this cap 12, the motor 20 is enclosed in the holder 10 and the upper support 11 except for the wiring 13. The elastic part 11c is formed in an annular shape, and is interposed between the upper metal part 11a and the lower metal part 11b. The diameter of the inner hole 11 c 1 of the elastic portion 11 c is smaller than the outer diameter of the motor 20.

  The motor 20 is elastically connected to the mount part HA via the upper support 11. The motor 20 is rotated by being controlled by an electronic control device (not shown) and includes a motor shaft 21. The motor shaft 21 is formed in a hollow shape and is rotatably supported by the holder body 10a via a bearing (not shown). The motor shaft 21 rotates with respect to the holder body 10 in accordance with the drive current output from the electronic control device.

  The ball screw mechanism 30 includes a ball screw shaft 31 as a linear motion member, a ball screw nut 32 as a rotating member, and a plurality of balls (not shown), and the rotational motion of the ball screw nut 32 according to the rotational output of the motor 20. Is converted into a linear motion of the ball screw shaft 31. The ball screw shaft 31 passes through the motor shaft 21, and has a male screw groove 31a and an outer spline groove 31b. The ball screw nut 32 is formed in a cylindrical shape and is rotatably supported by the holder main body 10a via a bearing Br1. The ball screw nut 32 is connected to the motor shaft 21 so as to be capable of rotating integrally (torque transmission is possible). The ball screw nut 32 has a female screw groove (not shown) on the inner periphery, and a plurality of balls are interposed between the female screw groove of the ball screw nut 32 and the male screw groove 31 a of the ball screw shaft 31. Yes. Thereby, when the ball screw nut 32 rotates, the ball screw shaft 31 can move in the vertical direction.

  The ball spline mechanism 40 includes a ball spline nut 41 and a plurality of balls (not shown), and supports the ball screw shaft 31 so as not to rotate with respect to the holder 10 and to be movable in the vertical direction. The ball spline nut 41 is formed in a cylindrical shape, and is fixed to the small diameter cylindrical portion 10 b of the holder 10 using a key 42. The ball spline nut 41 has an inner spline groove (not shown) on the inner periphery, and a plurality of balls are interposed between the inner spline groove of the ball spline nut 41 and the outer spline groove 31b of the ball screw shaft 31. It is disguised.

  In the first damping force generator A1 described above, the electronic control unit rotates the motor 20 according to the vibration of the sprung member SU and the unsprung member SD, and the rotational motion of the ball screw nut 32 is the linear motion of the ball screw shaft 31. Converted to (vertical movement). For this reason, when the ball screw shaft 31 moves up and down in response to the vibration of the sprung member SU and the unsprung member SD, the motor 20 rotates the ball screw nut 32 to resist the vertical movement of the ball screw shaft 31 (damping force). ).

  As shown in FIGS. 1 and 2, the second damping force generator A2 includes a cylinder member 50 assembled to the lower arm LA, a shaft member 51 connected to the ball screw shaft 31, a collar 52, A pair of upper and lower annular plates 53U, 53D, a pair of upper and lower upper bushes 54U (upper viscoelastic body), a lower bush 54D (lower viscoelastic body), and a nut 55 are provided, and elastic deformation of each bush 54U, 54D is provided. A damping force is generated.

  The cylinder member 50 extends in the vertical direction (axial direction) and is formed in a bottomed cylindrical shape. The cylinder member 50 accommodates the shaft member 51, the collar 52, the annular plates 53U and 53D, the bushes 54U and 54D, and the nut 55, and has an inward flange portion 50a at an intermediate portion in the vertical direction. . The bottom 50b of the cylinder member 50 is fixed to the lower arm LA via a lower bush (not shown). The upper part 50c of the cylinder member 50 is relatively movable in the vertical direction with respect to the outer periphery of the small diameter cylindrical part 10b of the holder 10 and the inner periphery of the upper cylindrical member 70 in the lateral force guide mechanism A4.

  The shaft member 51 extends coaxially with the ball screw shaft 31 and is disposed in the cylinder member 50. The shaft member 51 has a large-diameter shaft portion 51a on the upper side and a small-diameter shaft portion 51b on the lower side. The shaft member 51 is formed with a communication passage 51c through which pressurized air can flow. The small diameter shaft portion 51b passes through the inward flange portion 50a of the cylinder member 50, and a screw for screwing with the nut 55 is formed at the lower end portion of the small diameter shaft portion 51b. One end of the communication path 51c is provided on the peripheral surface of the large-diameter shaft portion 51a, and the other end of the communication path 51c is provided on the lower end of the small-diameter shaft portion 51b. The shaft member 51 may be configured integrally with the ball screw shaft 31 or may be configured separately.

  The collar 52 is for defining a vertical distance between the upper annular plate 53U and the lower annular plate 53D, and is assembled to the outer periphery of the small-diameter shaft portion 51b of the shaft member 51. The upper annular plate 53U passes through the small diameter shaft portion 51b of the shaft member 51, and is sandwiched between the large diameter shaft portion 51a of the shaft member 51 and the upper bush 54U. The lower annular plate 53D passes through the small-diameter shaft portion 51b of the shaft member 51, and is sandwiched between the nut 55 and the lower bush 54D.

  The upper bush 54U and the lower bush 54D are rubber which is a viscoelastic body (an elastic body having a damping performance), and is formed in a cylindrical shape. Further, the upper bush 54U and the lower bush 54D have gaps 54U1 and 54D1 (see FIG. 2) for adjusting the amount of elastic compression deformation, respectively. The upper bushing 54U and the lower bushing 54D are assembled in series between the small-diameter shaft portion 51b of the shaft member 51 and the cylinder member 50, and in an inward flange portion 50a of the cylinder member 50 in a state of being elastically compressed and deformed by a predetermined amount. Is pinched. Pressurized air cannot flow between the lower surface of the upper bushing 54U and the upper surface of the inward flange portion 50a of the cylinder member 50, and between the upper surface of the lower bushing 54D and the lower surface of the inward flange portion 50a of the cylinder member 50, Pressurized air cannot flow.

  Here, the assembly procedure of the second damping force generator A2 configured as described above will be described. First, the upper annular plate 53U is assembled to the upper end of the small-diameter shaft portion 51b of the shaft member 51, and the upper bush 54U is assembled to the upper outer periphery of the small-diameter shaft portion 51b. Next, the cylinder member 50 is assembled to the outer periphery of the shaft member 51, and the upper bush 54U is sandwiched between the upper annular plate 53U and the inward flange portion 50a of the cylinder member 50. Then, the lower bush 54D is assembled to the outer periphery of the lower portion of the small-diameter shaft portion 51b of the shaft member 51, and the collar 52 is assembled between the outer periphery of the small-diameter shaft portion 51b and the inner periphery of each bush 54U, 54D. Finally, the lower annular plate 53D is assembled to the outer periphery of the lower end of the small-diameter shaft portion 51b of the shaft member 51, and each bush 54U, 54D is elastically deformed by a predetermined amount to be formed on the small-diameter shaft portion 51b. The nut 55 is screwed into the existing screw. The screwing amount of the nut 55 can be adjusted as appropriate by adjusting the axial length (vertical length) of the collar 52. Therefore, by adjusting the screwing amount of the nut 55, it is possible to adjust the elastic compression amount of the bushes 54U and 54D and adjust the spring constant of the bushes 54U and 54D. Instead of screwing the nut 55 into the screw of the small diameter shaft portion 51b, the fixing member may be crimped to the lower end portion of the small diameter shaft portion 51b.

  In the above-described second damping force generator A2, an upper air chamber 56U defined by the cylinder member 50 and the shaft member 51 is formed above the upper bush 54U. Pressurized air is sealed in the upper air chamber 56U. A lower air chamber 56D defined by the cylinder member 50 and the shaft member 51 is formed below the lower bush 54D. Pressurized air is sealed in the lower air chamber 56D. The upper air chamber 56U and the lower air chamber 56D communicate with each other through a communication passage 51c formed in the shaft member 51. The damping force generated by the second damping force generator A2 not only changes the shape and material of the bushes 54U and 54D, the diameter of the communication passage 51c of the shaft member 51, but also the internal pressure of the air chambers 56U and 56D, It is possible to easily adjust by changing the volume of each air chamber 56U, 56D.

  As shown in FIG. 1, the air spring device A3 is disposed on the outer periphery of the first damping force generator A1 and the second damping force generator A2, and includes an air outer cylinder 60, an air inner cylinder 61, A diaphragm 62 and air supply / discharge means 63 are provided. The air outer cylinder 60 is a cylindrical body extending in the vertical direction, and is connected to the mount portion HA via the holder 10 and the upper support 11. The air inner cylinder 61 is a bottomed cylinder extending in the vertical direction, and the bottom of the air inner cylinder 61 is fixed to the outer periphery of the cylinder member 50. The diaphragm 62 is formed in an annular shape, the radially outer end portion 62 a is fixed to the lower end portion of the air outer cylinder 60, and the radially inner end portion 62 b is fixed to the upper end portion of the air inner cylinder 61. Yes. As a result, an air chamber 64 defined by the air outer cylinder 60, the air inner cylinder 61, the diaphragm 62, the holder main body 10a, the upper cylinder member 70, and a lower cylinder member 71 described later is formed. Pressurized air is enclosed.

  The air supply / discharge means 63 includes a supply / discharge control valve 63a connected to the air outer cylinder 60, a pump (not shown) connected to the supply / discharge control valve 63a, a pressure sensor (not shown), and the like. In addition, pressurized air can be supplied to and discharged from the air chamber 64. For this reason, the air spring device A3 uses the air supply / discharge means 63 to adjust the capacity of the pressurized air in the air chamber 64 and adjust the spring force that acts on the sprung member SU and the unsprung member SD, It is possible to adjust the distance between the sprung member SU and the unsprung member SD (adjust the vehicle height).

  As shown in FIGS. 1 and 2, the lateral force guide mechanism A4 includes an upper cylinder member 70 fixed to the holder body 10a, a lower cylinder member 71 fixed to the upper cylinder member 70, and an upper cylinder. An upper sliding bearing 72 assembled to the member 70 and a lower sliding bearing 73 assembled to the lower cylindrical member 71 are provided. The upper cylinder member 70 and the lower cylinder member 71 may be configured integrally with the holder body 10a.

  The upper cylindrical member 70 extends in the vertical direction (axial direction) from the lower end portion of the holder main body 10a to the outer periphery of the intermediate portion of the cylinder member 50, and the air chamber 64 of the air spring device A3 and the upper air chamber at the upper end portion. A communication hole 70a (communication means) for communicating with 56U is provided. The pressurized air that has flowed from the air chamber 64 into the upper cylindrical member 70 through the communication hole 70 a is an annular hole 50 c 1 formed between the outer periphery of the small diameter cylindrical portion 10 b of the holder 10 and the inner periphery of the upper portion 50 c of the cylinder member 50. It can flow to upper air chamber 56U through (communication means). The communication hole 70 a is formed so that the hole diameter of the communication hole 70 a is smaller than the hole diameter of the communication path 51 c of the shaft member 51. The annular hole 50c1 described above is formed such that the flow rate of the pressurized air flowing through the annular hole 50c1 is smaller than the flow rate of the pressurized air flowing through the communication passage 51c of the shaft member 51.

  The upper sliding bearing 72 is formed in an annular shape, and is fixed to the mounting portion 70b of the upper cylindrical member 70 by press fitting or the like. The lower sliding bearing 73 is formed in an annular shape, and is fixed to the mounting portion 71a of the lower cylindrical member 71 by press fitting or the like. The upper sliding bearing 72 and the lower sliding bearing 73 can smoothly move the cylinder member 50 in the vertical direction with respect to the upper cylindrical member 70 and the lower cylindrical member 71, and lateral force (shaft) acting on the cylinder member 50. (External force in the straight direction) can be received.

  In the first embodiment configured as described above, the motor 20 is rotationally driven by the electronic control unit according to the vibration of the sprung member SU and the unsprung member SD during vehicle travel, and the ball screw mechanism 30 The rotational movement of the screw nut 32 is converted into the linear movement (vertical movement) of the ball screw shaft 31. At this time, the upper bush 54U and the lower bush 54D can be elastically deformed in accordance with the vertical movement (relative movement) of the cylinder member 50 and the shaft member 51. For this reason, the first damping force generator A1 can obtain a damping force by the rotational drive of the motor 20, and the upper viscoelastic body and the lower viscoelastic body are elastically deformed, whereby the second damping force generator is obtained. A damping force can be obtained at, and vibrations of the sprung member SU and the unsprung member SD can be suppressed.

  Here, when the vibration of the sprung member SU and the unsprung member SD is a low-frequency vibration (for example, a vibration of 5 Hz or less), the motor 20 sufficiently follows the low-frequency vibration described above (the motor The ball screw shaft 31 and the shaft member 51 can smoothly move up and down in accordance with the rotational drive of 20), and a necessary and sufficient damping force (resistance force) can be obtained by the first damping force generator A1. However, at this time, the flange portion 50a of the cylinder member 50 moves up and down together with the small-diameter shaft portion 51b of the shaft member 51, and the upper bushing 54U and the lower bushing 54D do not elastically deform, so that the second damping force generator A2 Damping force cannot be obtained.

  On the other hand, when the vibration of the sprung member SU and the unsprung member SD is a high-frequency vibration (for example, a vibration of 10 Hz or more), the motor 20 becomes difficult to follow the above-described high-frequency vibration. Necessary and sufficient damping force cannot be obtained by the damping force generator A1. However, at this time, the flange portion 50a of the cylinder member 50 moves relative to the small diameter shaft portion 51b of the shaft member 51 in the vertical direction. By this relative movement, one of the upper bush 54U and the lower bush 54D is extended, and the other of the upper bush 54U and the lower bush 54D is compressed, and a damping force can be obtained by the second damping force generator A2. .

  When the flange portion 50a of the cylinder member 50 and the small-diameter shaft portion 51b of the shaft member 51 are relatively moved in the vertical direction (when the vibrations of the sprung member SU and the unsprung member SD are high-frequency vibrations), the upper bush Due to the elastic deformation of 54U and lower bush 54D, the volume in each air chamber 56U, 56D changes. Therefore, at this time, the pressurized air (high pressure air) in the air chambers 56U and 56D flows through the communication passage 51c of the shaft member 51, and resists (attenuates) the relative movement between the cylinder member 50 and the shaft member 51. Force) acts, and further damping force can be obtained by the second damping force generator.

  By the way, in this 1st Embodiment, since 2nd damping force generator A2 has generated damping force using air, it is not necessary to consider the temperature change and deterioration of air, and desired damping force Easy to get. In addition, since the working fluid linked to the elastic deformation of the upper bush 54U and the lower bush 54D is air and has a lower viscosity than when a working fluid (for example, oil) is employed as the working fluid, the cylinder member 50 and the shaft Even if the relative speed of the member 51 increases, the air flow between the air chambers 56U and 56D can sufficiently follow the relative speed. Furthermore, since air is a compressible fluid that can be compressed in each of the air chambers 56U and 56D, if the air flow between the air chambers 56U and 56D cannot follow the relative speed, Since the elastic deformation of the upper bush 56U and the lower bush 56D is ensured by the compression of the air in each of the air chambers 56U, 56D, an expected damping force corresponding to the relative speed is obtained also in this case. Therefore, it is possible to easily obtain the damping force sequentially required by the second damping force generator A2.

  Further, in the first embodiment, the suspension device SP is provided with the air spring device A3, and the communication hole 70a and the annular hole 50c1 for communicating the air chamber 64 of the air spring device A3 with the upper air chamber 56U. (Communication means) is provided. For this reason, even if minute air leakage occurs in the air chambers 56U and 56D, the pressurized air is supplied from the air supply / discharge means 63 to the air chamber 64, so that the communication holes 70a and It is possible to supply pressurized air into the upper air chamber 56U through the annular hole 50c1. Therefore, the internal pressures of the air chamber 64 and the air chambers 56U and 56D can always be kept at the desired pressures.

  In the first embodiment, the communication hole 70a is formed so that the diameter of the communication hole 70a is smaller than the diameter of the communication path 51c formed in the shaft member 51, and the annular hole 50c1. Is formed such that the flow rate of the pressurized air flowing through the annular hole 50c1 is smaller than the flow rate of the pressurized air flowing through the communication passage 51c of the shaft member 51. As a result, when the relative speed between the cylinder member 50 and the shaft member 51 is high, that is, when the vibration of the sprung member SU and the unsprung member SD is a high-frequency vibration, the additional fluid flowing through the communication hole 70a and the annular hole 50c1 is added. The flow rate of the pressurized air decreases (substantially becomes zero), and the internal pressures of the air chambers 56U and 56D tend to be different. On the other hand, when the relative speed between the cylinder member 50 and the shaft member 51 is small, that is, when the vibration of the sprung member SU and the unsprung member SD is a low frequency vibration, the pressure that flows through the communication hole 70a and the annular hole 50c1. The air flow rate increases, and the internal pressures of the air chambers 56U and 56D are unlikely to vary.

  Therefore, a large damping force can be generated when the relative speed between the cylinder member 50 and the shaft member 51 is large, and a small damping force can be generated when the relative speed between the cylinder member 50 and the shaft member 51 is small. It is. Accordingly, it is possible to easily change the damping force generated by the second damping force generator A2 in accordance with the relative speed between the cylinder member 50 and the shaft member 51 by the communication hole 70a and the annular hole 50c1.

  Incidentally, in the suspension device (electric active suspension device) in which the first damping force generator A1 generates a damping force by the rotational drive of the motor 20, the vibration of the sprung member SU and the unsprung member SD is a low-frequency vibration. (When the relative speed between the cylinder member 50 and the shaft member 51 is small), the motor 20 (first damping force generator A1) can sufficiently follow the low-frequency vibration described above, and has a large damping force. Can be generated. However, when the vibration of the sprung member SU and the unsprung member SD is a high-frequency vibration (when the relative speed between the cylinder member 50 and the shaft member 51 is large), the motor 20 follows the high-frequency vibration described above. It becomes difficult to reduce the damping force generated by the first damping force generator A1. For this reason, in the electric active suspension device, when the vibration of the sprung member SU and the unsprung member SD is a high-frequency vibration, the ratio depending on the damping force generated by the second damping force generator A2 increases.

  Therefore, as described above, the damping force characteristics of the second damping force generator A2 using the communication hole 70a and the annular hole 50c1 (communication means) (the vibrations of the sprung member SU and the unsprung member SD are high-frequency vibrations). In some cases, a large damping force is generated, and when the vibration of the sprung member SU and the unsprung member SD is a low frequency vibration, a damping force characteristic that generates a small damping force) is preferable for the electric active suspension apparatus. It is a force characteristic.

  In the first embodiment, the upper cylindrical member 70 and the lower cylindrical member 71 (cylinder part) are connected to the holder 10, and an upper sliding bearing 72 is provided between the upper cylindrical member 70 and the cylinder member 50. A lower sliding bearing 73 is provided between the lower cylindrical member 71 and the cylinder member 50. For this reason, when a lateral force (external force in the axial direction) acts on the lower arm LA that is a part of the unsprung member SD, this lateral force is transmitted from the cylinder member 50 to the upper sliding bearing 72 and the lower sliding bearing 73. The upper slide bearing 72 and the lower slide bearing 73 are mainly used. The upper sliding bearing 72 and the lower sliding bearing 73 include a cylinder member 50 assembled to the unsprung member SD and an upper cylindrical member 70 extending in the vertical direction from the holder 10 to the outer periphery of the cylinder member 50. Since it is provided between the lower cylindrical member 71, the vertical distance from the lower arm LA to the upper sliding bearing 72 and the lower sliding bearing 73 is small. Therefore, it is possible to reduce the rotational moment (torque moment) generated in the members that slide while receiving the lateral force (upper sliding bearing 72, lower sliding bearing 73), and to improve the reliability of the member that receives the lateral force. It is possible to increase.

  In the first embodiment, the diameter of the inner hole 11 c 1 of the elastic portion 11 c in the upper support 11 is smaller than the diameter of the outer periphery of the motor 20. For this reason, since the elastic part of the upper support is not penetrated by the motor as described in Patent Document 1, for example, the volume of the elastic part 11c of the upper support 11 can be increased, and the elastic part 11c of the upper support 11 can be increased. It is possible to reduce the spring constant (spring characteristic). Therefore, by reducing the spring constant of the elastic portion 11c of the upper support 11, it is possible to improve the riding comfort against high-frequency vibration (vibration that feels terrible), reduce noise and vibration, and unsprung. It is possible to mitigate the impact caused by pushing up the member SD.

  Note that, by reducing the spring constant of the elastic portion 11c in the upper support 11, the lower end side of the suspension device SP can easily tilt (swing) with respect to the upper end side of the suspension device SP. For this reason, when a lateral force acts on the lower arm LA, it is possible to reduce the intensive load acting on each component of the suspension device SP, and it is possible to improve the reliability of each component of the suspension device SP. is there.

  In the first embodiment, the cap 12 is assembled in the inner hole 11b1 of the lower metal fitting 11b in the upper support 11, and the motor 20 allows the motor 20 and the upper support except the wiring 13 by the cap 12. 11 is enclosed. For this reason, the operating sound of the motor 20 can be reduced. In the first embodiment, the second damping force generator A2 uses the bushes 54U and 54D and pressurized air, so that the second damping force generator uses, for example, a hydraulic damper device. Compared to the configuration, the second damping force generator can be configured to be suitable for the environment in consideration of recyclability and the like.

  In the first embodiment configured as described above, an upper sliding bearing 72 is provided between the upper cylindrical member 70 and the cylinder member 50, and a lower sliding bearing 73 is provided between the lower cylindrical member 71 and the cylinder member 50. However, it is also possible to provide a rolling bearing 172 between the cylindrical member 170 and the cylinder member 50 as in the second embodiment shown in FIG.

  In the second embodiment, as shown in FIG. 3, the cylindrical member 170 extends in the vertical direction from the lower end of the holder main body 10a to the outer periphery of the cylinder member 50, and is constituted by a single member. Has been. Since the configuration other than the configuration of the second embodiment described above is substantially the same as the configuration of the first embodiment described above, the corresponding parts are denoted by the same reference numerals and the description thereof is omitted.

  In the second embodiment described above, since the rolling bearing 172 is provided between the cylindrical member 170 and the cylinder member 50, the first embodiment described above (when each of the sliding bearings 72 and 73 is provided) is provided. In comparison, the sliding resistance with respect to the cylinder member 50 can be reduced, and the cylinder member 50 can be smoothly moved in the axial direction with respect to the cylindrical member 170. However, since the cylinder member 50 is in point contact with the rolling bearing 172, compared with the first embodiment described above (when the cylinder member 50 is in line contact or surface contact with the sliding bearings 72 and 73), it is lateral. The load (surface pressure) acting on the cylinder member when a force is applied increases. The other effects of the second embodiment are substantially the same as the effects of the first embodiment described above, and are therefore omitted.

  In 2nd Embodiment comprised as mentioned above, the cylinder member 170 (cylinder part) extended in the up-down direction to the holder 10 at the outer periphery of the cylinder member 50 is connected, and this cylinder member 170 and the cylinder member 50 are connected. The rolling bearing 172 is provided between them, but as in the third embodiment shown in FIG. 4, a cylinder portion 270 extending in the vertical direction to the outer periphery of the holder 10 is connected to the cylinder member 50. It is also possible to provide a rolling bearing 272 between the cylindrical portion 270 and the holder 10.

  In the third embodiment, the air inner cylinder 61 in the air spring device A3 described above is not provided, and the radially outer end portion 262a of the diaphragm 262 is fixed to the lower end portion of the air outer cylinder 60, and the diaphragm A radially inner end 262 a of 262 is fixed to the cylinder member 50. Since the configuration other than the configuration of the above-described third embodiment is substantially the same as the configuration of the above-described second embodiment, the same reference numerals are given to corresponding portions, and description thereof is omitted.

  In the above-described third embodiment, the cylinder portion extending in the vertical direction from the holder 10 is not provided on the outer periphery of the cylinder member 50, and the air inner cylinder in the air spring device A3 is provided on the outer periphery of the cylinder member 50. Since it is not provided, the outer diameter of the diaphragm 262 can be reduced as compared with the second embodiment described above, and the spring constant of the air spring device A3 can be reduced. However, since the vertical distance between the rolling bearing 272 that receives the lateral force and the lower arm LA is larger than the vertical distance between the rolling bearing 172 and the lower arm LA of the second embodiment described above, As compared with the second embodiment, the rotational moment (torsional moment) acting on the rolling bearing 272 is increased. The other operations and effects of the third embodiment are substantially the same as the operations and effects of the second embodiment described above, and are therefore omitted.

  In each of the above-described embodiments, the upper bush 54U and the lower bush 54D are made of rubber that is a viscoelastic body (an elastic body having a damping performance), but the upper bush 54U and the lower bush 54D are viscoelastic bodies. For example, the upper bushing 54U and the lower bushing 54D may be formed by foamed urethane or hard urethane.

  In each of the above embodiments, the communication member 56c that connects the upper air chamber 56U and the lower air chamber 56D is provided in the shaft member 51. However, the upper air chamber 56U and the lower air chamber 56D communicate with each other. It is also possible to provide the communication path to be provided on the peripheral wall of the cylinder member 50. It is also possible to provide a communication pipe that connects the upper air chamber 56U and the lower air chamber 56D, and to provide a communication path that connects the upper air chamber 56U and the lower air chamber 56D.

  Further, in each of the above embodiments, the communication hole 70a and the annular hole 50c1 (communication means) for communicating the air chamber 64 of the air spring device A3 and the upper air chamber 56U are provided, but the air of the air spring device A3 is provided. It is also possible to provide communication means for communicating the chamber 64 and the lower air chamber 56D.

  Further, in each of the above-described embodiments, the air spring device A3 that applies the spring force to the sprung member SU and the unsprung member SD is arranged on the outer periphery of the first damping force generator A1 and the second damping force generator A2. However, instead of the air spring device A3, a coil spring that applies a spring force to the sprung member SU and the unsprung member SD may be provided.

  Further, in each of the above-described embodiments, the first damping force generator A1 is provided upward (the motor 20 is assembled to the sprung member SU), and the second damping force generator A2 is provided downward (cylinder member). 50 is assembled to the unsprung member SD), the first damping force generator is provided below (the motor is assembled to the unsprung member SD), and the second damping force generator A2 is provided above. It is also possible to carry out (by attaching the cylinder member to the sprung member SU).

SP ... Suspension device, SU ... Spring member, SD ... Unsprung member, HA ... Mount part, LA ... Lower arm, A1 ... First damping force generator, A2 ... Second damping force generator, A3 ... Air spring device, A4 ... Lateral force guide mechanism, 10 ... Holder, 11 ... Upper support, 11c ... Elastic part, 11c1 ... Inner hole, 12 ... Cap, 20 ... Motor, 30 ... Ball screw mechanism, 31 ... Ball screw shaft, 32 ... Ball screw nut, 40 DESCRIPTION OF SYMBOLS ... Ball spline mechanism, 41 ... Ball spline nut, 50 ... Cylinder member, 50a ... Inward flange part, 50c1 ... Annular hole, 51 ... Shaft member, 51c ... Communication path, 52 ... Collar, 53U, 53D ... Annular plate, 54U ... Upper bush, 54D ... lower bush, 55 ... nut, 56U ... upper air chamber, 56D ... lower air chamber 60 ... Air outer cylinder, 61 ... Air inner cylinder, 62 ... Diaphragm, 63 ... Air supply / discharge means, 63a ... Supply / discharge control valve, 64 ... Air chamber, 70 ... Upper cylinder member, 70a ... Communication hole, 71 ... Lower cylinder 72, upward sliding bearing, 73 ... downward sliding bearing, 170 ... cylindrical member, 172 ... rolling bearing, 262 ... diaphragm, 270 ... cylindrical portion, 272 ... rolling bearing

Claims (3)

Between the sprung member and the unsprung member, a first damping force generating device and a second damping force generating device that generate a damping force with respect to the approaching or separating operation of the sprung member and the unsprung member are arranged in series. And
The first damping force generating device includes a motor assembled to a sprung member, a rotating member, and a linear motion member. And a conversion mechanism for converting to
The second damping force generator includes a cylinder member that is assembled to an unsprung member and extends in a vertical direction, and is arranged in the cylinder member so as to be connected to the linear motion member of the conversion mechanism. A shaft member that is relatively movable in the vertical direction with respect to the cylinder member, and is assembled in series between the shaft member and the cylinder member, and is elastically deformed by the relative movement of the cylinder member and the shaft member in the vertical direction. In a vehicle suspension apparatus comprising an upper viscoelastic body and a lower viscoelastic body,
A pair of upper and lower air chambers that are partitioned by the cylinder member and the shaft member and communicate with each other through a communication path are formed above the upper viscoelastic body and below the lower viscoelastic body ,
On the outer periphery of the first damping force generation device and the second damping force generation device, there is an air chamber filled with pressurized air and air supply / discharge means capable of supplying and discharging the pressurized air to and from the air chamber. An air spring device that applies a spring force to the sprung member and the unsprung member is disposed,
A suspension device for a vehicle, comprising a communication means for communicating the air chamber of the air spring device with any one of the air chambers . The vehicle suspension device according to claim 1 ,
A cylindrical portion that extends in the vertical direction to the outer periphery of the cylinder member is connected to a support member that is assembled to the sprung member and supports the motor, and a bearing is provided between the cylindrical portion and the cylinder member. A suspension apparatus for a vehicle, characterized in that is provided. The vehicle suspension device according to claim 1 or 2 ,
The motor is elastically connected to the sprung member via an upper support,
The upper support has an annular elastic part, and the diameter of the inner hole of the elastic part is smaller than the diameter of the outer periphery of the motor.

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