JP2006177478A - Shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the temperature rise of a motor of a shock absorber. <P>SOLUTION: The shock absorber comprises: a first cylinder 2; a second cylinder 5 inserted into the first cylinder 2; a motion converting mechanism H mounted between the first cylinder 2 and the second cylinder 5 for converting relative motion between the first cylinder 2 and the second cylinder 5 into rotating motion; and the motor 1 fixed to either one of the first cylinder 2 or the second cylinder 5 to which the rotating motion is transmitted. It controls relative movement between the first cylinder 2 and the second cylinder 5 with the output torque of the motor 1. Passages 30a, 21a communicate a space R formed between the first cylinder 2 and the second cylinder 5 with the inside of the motor 1, while a passage 30b communicates the inside with the outside of the motor 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shock absorber that controls expansion and contraction with torque output from a motor.

As this kind of shock absorber, a coil spring that elastically supports the vehicle body, a screw shaft that is rotatably engaged with a ball screw nut that is connected to the axle side, and one end of the screw shaft that is connected to the vehicle body side. Some motors are configured to actively control the relative movement between the vehicle body and the axle with the rotational torque generated by the motor.
Japanese Patent Laid-Open No. 08-197931 (paragraph number 0023, FIG. 1)

  In this type of shock absorber, the motor constantly rotates while the vehicle is running, so that the motor continues to rotate, and as a result, a current flows through the motor winding continuously.

  Then, the motor windings generate heat, and when the motor temperature rises severely due to the heat generated by the windings, the insulation deteriorates due to chemical changes in the insulation film of the conductors that form the windings. There is a risk that the motor itself may be damaged due to electric leakage or the like, and there is a risk of demagnetization of the magnet due to a temperature rise of the motor.

  In this type of shock absorber, the motor is an indispensable part that generates a damping force. Therefore, damage to the motor impairs the function of the suspension device.

  Therefore, the present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to suppress an increase in the temperature of the shock absorber motor.

  In order to achieve the above-described object, the first cylinder, the second cylinder inserted into the first cylinder, the first cylinder and the second cylinder interposed between the first cylinder and the second cylinder A motion conversion mechanism that converts relative motion with the second cylinder into rotational motion, and a motor that is fixed to one of the first cylinder and the second cylinder and that transmits the rotational movement. In the shock absorber for controlling the relative movement of the first cylinder and the second cylinder, a passage communicating the space formed in the first cylinder and the second cylinder and the motor, and a path communicating the inside and outside of the motor And is provided.

  According to the present invention, the shock absorber continuously expands and contracts while the vehicle is running, so that gas frequently flows into and out of the space, and this gas is flowed in and out through the motor. Thus, the winding is quickly cooled by the passage of gas in the motor.

  Therefore, the temperature rise of the winding is suppressed, heat is not trapped in the motor, the temperature rise of the motor can be suppressed, and the insulation is deteriorated due to the chemical change of the insulating coating of the conductive wire forming the winding, As a result, there is no risk of electric leakage and the motor itself being damaged.

  Furthermore, since damage to the motor can be avoided, it is possible to prevent a situation in which the function of the shock absorber is impaired.

  In addition, the temperature rise of the motor can be suppressed, and gas passes through the gap between the magnet and the core to exert an air curtain effect, thereby preventing the heat of the winding from being transferred to the magnet. There is no risk of performance deterioration such as a decrease in torque generated by the motor due to thermal demagnetization of the magnet.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a diagram conceptually illustrating a shock absorber according to an embodiment. FIG. 2 is a longitudinal sectional view of a shock absorber according to another embodiment.

  As shown in FIG. 1, the shock absorber in the present embodiment includes an outer cylinder 2 as a first cylinder, an inner cylinder 5 as a first cylinder that is slidably inserted into the outer cylinder 2, and an outer cylinder. 2, a ball screw nut 4 provided in the ball screw nut 4, a screw shaft 3 that is rotatably engaged with the ball screw nut 4, and a motor 1 that is fixed to the upper end of the inner cylinder 5 and connected to the screw shaft 3. When the shock absorber expands and contracts, that is, when the outer cylinder 2 as the first cylinder and the inner cylinder 5 as the second cylinder move relative to each other, the linear movement of the ball screw nut 4 is changed to the rotational movement of the screw shaft 3. And the rotational motion is transmitted to the shaft 10 of the motor 1 to generate an electromagnetic force in the motor 1, and the torque that resists the rotation of the shaft 10 due to the electromagnetic force is applied to the rotational motion of the screw shaft 3. It is used as a damping force to suppress the linear motion of the ball screw nut 4 by suppressing It is intended that can be inhibited relative axial movement of the inner cylinder 5 and outer cylinder 2.

  In the case of the present embodiment, the shock absorber is connected to the axle side member of the vehicle via the eye E provided at the lower end in FIG. It is connected to the vehicle body side member via the mount 20, and as a result, relative movement between the axle side member and the vehicle body side member can be suppressed.

 Hereinafter, the detailed structure of each part will be described. The motor 1 is mounted and connected in a mount inner cylinder 21 of a mount 20 connected to the upper end in FIG. 1 of the inner cylinder 5, and the shaft 10 of the motor 1 is in ball bearings 8 and 9 in the inner cylinder 5. Is connected to a screw shaft 3 that is rotatably inserted through the shaft. Note that the shaft 10 of the motor 1 and the screw shaft 3 may be integrally formed.

 Further, as described above, the mount 20 for attaching the shock absorber to the vehicle is provided at the upper end in FIG. 1 of the inner cylinder 5. The mount 20 includes a mount inner cylinder 21 and a mount outer cylinder. 22 and an anti-vibration rubber 23 for connecting the mount inner cylinder 21 and the mount outer cylinder 22 to the bottom of the mount inner cylinder 21 in addition to the hole into which the shaft 10 of the motor 1 is inserted. A hole 21 a communicating with the inside of the cylinder 5 is provided.

 Specifically, the mount outer cylinder 22 is connected to the vehicle body side, and the shock absorber is connected to the vehicle body side.

 On the other hand, as shown in FIG. 1, the motor 1 includes a case 30, the shaft 10, a magnet 32 attached to the outer periphery of the shaft 10 via a cylindrical yoke 31, and the inner periphery of the case 30. A core 33 that is an armature core attached so as to face the magnet 32 and a winding 34 fitted to the core 33 are provided, and is configured as a so-called brushless motor.

 The magnet 32 is formed in an annular shape and has a divided magnetic pole pattern in which the N pole and the S pole appear alternately along the circumference, but the plurality of magnets are bonded to form an annular shape. It may be formed.

 The yoke 31 is provided with a plurality of through holes 31a along the axis and at equal intervals on a concentric circle so that gas can pass through the through holes 31a.

 The motor 1 is connected to an external power source so as to be able to control the rotational torque of the shaft 10 and is adjusted to obtain a desired damping force. By driving, this shock absorber functions not only as a shock absorber but also as an actuator.

 Incidentally, the motor 1 is provided with a rotor position detecting means 40, and an outer cylinder 2 and an inner cylinder 5 in which a shock absorber is generated according to the state of rotation of the rotor (rotation angle, angular velocity, etc.), As a result, the relative movement between the vehicle body side member and the axle side member can be controlled. Specifically, for example, a Hall element, a magnetic sensor, or an optical sensor may be used as the position detection unit 40.

 In the present embodiment, the motor 1 is a brushless motor, but various motors such as a DC motor, an AC motor, an induction motor, and the like can be used as long as they can be used as an electromagnetic force generation source.

 The case 30 is provided with holes 30a and 30b that allow passage of gas at the upper end and the lower end in FIG. 1, and the hole 30b provided on the upper end side communicates with the inside and outside of the case 30. That is, the hole 30 a provided on the other lower end side is communicated with the hole 21 a provided in the mount inner cylinder 21.

 Further, a seal member 35, in this case, an O-ring, is interposed between the lower end surface in FIG. 1 of the case 30 and the bottom inner surface of the mount inner cylinder 21. There is no gas leakage from between.

 Further, the hole 30b is provided with a filter F for preventing water droplets from entering the motor 1, and the filter F is specifically obtained by processing a polyurethane resin, a fluororesin, or the like. What is necessary is just to form with a raw material, and the thing provided with the fine hole of the grade which can prevent not only water droplets but invasion of dust etc. is preferable.

 Incidentally, in the present embodiment, the mount inner cylinder 21 of the mount 20 may be used as a case of the motor 1. In this case, the core 33 and the winding 34 are attached to the mount inner cylinder 21, and A lid for closing the upper end opening in FIG.

 Next, the screw shaft 3 connected to the shaft 10 is provided with a screw groove on the outer periphery thereof, and is a ball that is non-rotatably provided at the upper end portion in FIG. 1 of the connecting tube 6 rising from the bottom of the outer tube 2 described above. The screw nut 4 is rotatably screwed.

  That is, in the case of this embodiment, the motion conversion mechanism H is constituted by the screw shaft 3 and the ball screw nut 4, and when the ball screw nut 4 performs a linear motion in the vertical direction in FIG. Since the rotation of the ball screw nut 4 is restricted by the outer cylinder 2 fixed to the axle side, the screw shaft 3 is forcibly rotated, and conversely, the motor 1 is driven to rotate the screw shaft 3. Then, since the rotation of the ball screw nut 4 is restricted, it is possible to move the ball screw nut 4 in the vertical direction.

 In addition, bearings 11 and 12 are provided between the outer cylinder 2 and the inner cylinder 5 to prevent the inner cylinder 5 from being shaken with respect to the outer cylinder 2, and the lower ends of the connecting cylinder 6 and the inner cylinder 5 in FIG. Is provided with a bearing 15 between which the axial displacement of the connecting cylinder 6 and the inner cylinder 5 is prevented. As a result, the axial displacement of the screw shaft 3 with respect to the ball screw nut 4 is prevented, Thereby, it is possible to prevent a load from being concentrated on a part of the balls (not shown) of the ball screw nut 4 and to prevent the ball or the screw groove of the screw shaft 3 from being damaged.

 In addition, since the ball or the screw groove of the screw shaft 3 can be prevented from being damaged, the smooth movement of each of the rotation of the screw shaft 3 with respect to the ball screw nut 4 and the movement of the shock absorber in the expansion / contraction direction can be maintained. Since the smoothness of each operation can be maintained, the function as a shock absorber is not impaired, and the failure of the shock absorber can be prevented.

  Further, a dust seal 13 is provided between the outer cylinder 2 and the inner cylinder 5 and above the bearing 11, and the inside of the outer cylinder 2 is substantially sealed.

 Further, a hole 5a is formed in the lower side portion of the inner cylinder 5 in FIG. 1, and the inside of the outer cylinder 2 and the inside of the inner cylinder 5 are communicated with each other through the hole 5a. A substantially sealed space R is formed between the inside and the inside of the inner cylinder 5.

 The connecting cylinder 6 is not necessarily formed in a cylindrical shape, and may be any one that can connect the ball screw nut 4 to the outer cylinder 2 in a state where the rotation of the ball screw nut 4 is restricted.

 Further, the bearing 15 may be omitted, and even in this case, the shaft runout of the screw shaft 3 with respect to the ball screw nut 4 is prevented by the bearings 11 and 12 described above, so there is no inconvenience. By omitting, the inner cylinder 5 and the outer cylinder 2 communicate with each other to form a space R, so that the hole 5a can be omitted.

  The space R communicates with the motor 1 through the holes 30a and 21a. The holes 30a and 21a serve as a passage that communicates the motor 1 with the space R.

  In the present embodiment, the motion conversion mechanism H is constituted by a ball screw nut and a screw shaft. However, this may be constituted by another configuration, for example, a rack and pinion, or a ball screw. The nut may be replaced with a simple nut.

  Now, the shock absorber of the present invention is configured as described above, and the operation thereof will be described below.

  First, when the shock absorber expands and contracts, that is, when the inner cylinder 5 moves up and down in FIG. 1 with respect to the outer cylinder 2, the linear motion of the ball screw nut 4 connected to the outer cylinder 2 is The ball screw mechanism of the screw nut 4 and the screw shaft 3 is converted into a rotational motion of the screw shaft 3, and the shaft 10 of the motor 1 connected to the screw shaft 3 also rotates.

  When the shaft 10 of the motor 1 exhibits a rotational motion, the winding 34 in the motor 1 crosses the magnetic field of the magnet 32, and an induced electromotive force is generated. The shaft 10 of the motor 1 is electromagnetically caused by the induced electromotive force. Torque due to force acts, and the torque suppresses the rotational movement of the shaft 10.

  The effect of suppressing the rotational movement of the shaft 10 is to suppress the rotational movement of the screw shaft 3, and the rotational movement of the screw shaft 3 is suppressed, so that the linear movement of the ball screw nut 4 is suppressed. The shock absorber generates a damping force by the electromagnetic force and absorbs and relaxes vibration energy.

  At this time, when the current is actively supplied to the winding 34, the expansion / contraction of the shock absorber can be freely controlled by adjusting the torque acting on the shaft 10, that is, the control force generated by the shock absorber can be generated. Since it is possible to control freely within a range, it is possible to make the damping characteristic of the shock absorber variable or to make the shock absorber function as an actuator.

  In turn, when the shock absorber is extended, the inner cylinder 5 is withdrawn from the outer cylinder 2, so that the space R is enlarged. In the space R, the holes 30 b and 30 a provided in the case 30 of the motor 1 and the mount inner cylinder 21 are provided. Since the gas flows in through the hole 21a provided in the gas, the gas always passes through the motor 1.

  On the contrary, when the shock absorber contracts, the inner cylinder 5 enters from the outer cylinder 2 so that the space R contracts. From the space R, the holes 30 b and 30 a provided in the case 30 of the motor 1 and the mount inner cylinder 21 are contracted. Since the gas is discharged through the provided hole 21a, the gas always passes through the motor 1 and is exhausted.

  The inflow and discharge of the gas into the space R are frequently performed because the shock absorber constantly expands and contracts while the vehicle is traveling. However, since the inflow and discharge of the gas are performed through the motor 1, the winding is performed. The wire 34 is quickly cooled by the passage of gas in the motor 1.

  Therefore, the temperature rise of the winding 34 is suppressed, the heat is not accumulated in the motor 1, the temperature rise of the motor 1 can be suppressed, and the insulating property is improved by the chemical change of the insulating film of the conductive wire forming the winding 34. As a result, there is no risk that the motor itself will be damaged due to leakage of electric current.

  Furthermore, since damage to the motor 1 can be avoided, it is possible to prevent a situation in which the function of the shock absorber is impaired.

  In addition, the temperature rise of the motor 1 can be suppressed, and the gas passes through the gap between the magnet 32 and the core 33 to exert an air curtain effect, so that the heat of the winding 34 is transmitted to the magnet 32. Therefore, there is no fear of performance deterioration such as a decrease in torque generated by the motor 1 due to thermal demagnetization of the magnet 32.

  Further, as shown in FIG. 1, since the yoke 31 is provided with a plurality of through holes 31a at equal intervals on a concentric circle, the gas passes through the gap in addition to the gap between the magnet 32 and the core 33. Since it can pass through the hole 31a, heat can be dissipated from the yoke 31 to the gas, so that the effect of preventing thermal demagnetization of the magnet 32 is further enhanced, and the pressure loss when the gas passes through the motor 1 is excessive. This prevents the shock absorber from expanding and contracting quickly.

  When the gas flows in, the gas always passes through the hole 30b provided in the case 30. Since the filter 30 is provided in the hole 30b, water drops such as rainwater enter the motor 1. As a result, the motor 1 is protected from rainwater and the like, and at the same time, the ball bearings 8 and 9, the ball bearing (not shown) in the motor 1, the screw shaft 3, the ball screw nut 4, etc. This prevents water droplets from adhering and causing rust, thereby ensuring a smooth expansion and contraction of the shock absorber.

  Further, when the filter F prevents dust and the like from entering, the motor 1 and the motion conversion mechanism H can be protected from dust and the like, and in this respect, a smooth expansion / contraction operation of the shock absorber is ensured.

 Next, a shock absorber according to another embodiment shown in FIG. 2 will be described. In addition, about the member similar to the buffer in one above-mentioned embodiment, it shall attach | subject the same code | symbol and suppose that the detailed description is abbreviate | omitted.

  In the shock absorber in the other embodiment, the motor portion is different from the shock absorber in the one embodiment, and the other portions have the same configuration as the shock absorber in the one embodiment.

 This different portion will be described in detail. A shock absorber motor 51 according to another embodiment includes a case 60, the shaft 10, and a cylindrical yoke 52 on the outer periphery of the shaft 10 as shown in FIG. A so-called brushless motor including a magnet 53 attached to the core 53, an armature core 53 attached to the inner periphery of the case 60 so as to face the magnet 32, and a winding 34 fitted to the core 53. It is configured as.

 The core 53 is provided with a plurality of through holes 53a along the axis and at equal intervals on a concentric circle so that gas can pass through the through holes 53a.

 In addition, holes 60 a and 60 b that allow passage of gas are formed at the upper end and the lower end in FIG. 2 of the case 60, and the holes 60 b provided on the upper end side communicate with the inside and outside of the case 60. However, the opening end of the hole 60b on the outer side of the case 60 is formed to face downward.

 Furthermore, a filter F similar to that of the embodiment for preventing water droplets from entering the motor 51 is provided at the opening end of the hole 60b on the outer side of the case.

  The difference is the above, and in the shock absorbers of the other embodiments as well, the gas can be flowed into and out of the space R by expansion and contraction of the shock absorbers, so basically the buffer in the above-described one embodiment. However, in the shock absorbers of the other embodiments, the opening end on the case outer side of the hole 60b faces downward, so that water drops such as rainwater enter the motor 51. This is further prevented as compared with the shock absorber in the embodiment.

  Further, in the shock absorber in this other embodiment, since the gas also passes through the through-hole 53a of the armature core 53, the heat can be dissipated from the core 53 to the gas. It is possible to effectively prevent thermal demagnetization of the magnet 32 by suppressing the temperature rise, and it is possible to prevent the pressure loss when the gas passes through the motor 1 from being excessive, and to expand and contract the shock absorber. It can be swiftly conditioned.

  The yoke 52 may be provided with a through hole in the same manner as the yoke 31 in the embodiment. In this case, heat can be dissipated from the yoke 52 in addition to heat dissipated from the core 53. It becomes possible to further prevent thermal demagnetization of the magnet 32.

  In each of the above-described embodiments, the motor 1 is fixed to the inner cylinder 5 side as the second cylinder, but the motor 1 connected to the screw shaft 3 is fixed to the outer cylinder 2 side as the first cylinder. The ball screw nut 4 may be provided on the inner cylinder 5 side.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

It is a figure which shows notionally the buffer in one Embodiment. It is a longitudinal cross-sectional view of the buffer in other embodiment.

Explanation of symbols

1, 51 Motor 2 First cylinder outer cylinder 3 Screw shaft 4 Ball screw nut 5 Second cylinder inner cylinder 6 Connecting cylinder 8, 9 Ball bearing 10 Shaft 11, 12, 15 Bearing 13 Dust seal 20 Mount 21 Inside mount Cylinder 5a, 21a, 30a, 30b Hole 22 Mount outer cylinder 23 Anti-vibration rubber 30, 60 Case 31, 52 Yoke 31a, 53a Through hole 32 Magnet 33, 53 Core 34 Winding 35 Seal member 40 Position detecting means E Eye H Motion Conversion mechanism

Claims (5)

A first cylinder, a second cylinder inserted into the first cylinder, and a relative movement between the first cylinder and the second cylinder interposed between the first cylinder and the second cylinder; A movement converting mechanism for converting to a rotary movement; and a motor that is fixed to one of the first cylinder and the second cylinder and that transmits the rotary movement. The first cylinder and the second cylinder are output torque of the motor. In the shock absorber for controlling the relative movement of the first and second cylinders, there is provided a passage communicating between the space formed in the first cylinder and the second cylinder and the motor, and a path communicating between the inside and outside of the motor. Shock absorber. 2. The shock absorber according to claim 1, wherein a filter for preventing at least water droplets from entering the motor is provided in a passage communicating between the inside and outside of the motor. The shock absorber according to claim 1 or 2, wherein a passage communicating between the inside and outside of the motor is provided such that an outlet thereof faces downward. The shock absorber according to any one of claims 1 to 3, wherein a through hole through which gas passes is provided in a yoke of the motor. The shock absorber according to any one of claims 1 to 4, wherein a through hole through which gas passes is provided in a core of an armature of a motor.

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