JP2006067648A - Motor and buffer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent thermal demagnetization of a magnet in a motor and a deterioration of a performance of a buffer. <P>SOLUTION: The motor M1 is provided with a rotor R having a yoke 4 and the magnet 8 mounted on an outer circumference of the yoke 4. At least one penetration hole 5 is provided in the yoke 4 and opens at both ends. Since heat transmitted to the magnet 8 is dissipated from the penetration hole 5 in addition to the outer circumference of the rotor R, the magnet 8 is prevented from reaching a high temperature. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement of a motor, and also relates to a shock absorber that uses a torque generated by the motor as a damping force that suppresses linear motion of a motion conversion mechanism.

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 side member and the axle side member with rotational torque generated by the motor.
Japanese Patent Laid-Open No. 08-197931 (paragraph number 0023, FIG. 1)

  In the conventional shock absorber, in controlling the posture, as described above, the torque generated by the motor is used as a control force for suppressing the relative linear motion of the vehicle body side member and the axle side member. During traveling, a current constantly flows through the windings of the motor.

  Therefore, since a current always flows through the winding of the motor, the winding itself generates heat. When the motor temperature rises greatly due to the heating of the winding, the heat of the winding is transmitted to the magnet. In addition, there is a risk that the performance of the motor is deteriorated due to a decrease in torque due to the high temperature of the magnet or, in some cases, irreversible demagnetization of the magnet.

  In particular, in this type of shock absorber, the motor is an indispensable part that generates a damping force. Therefore, the deterioration of the performance of the motor immediately leads to the deterioration of the performance of the shock absorber.

  Therefore, the present invention has been created in consideration of the above-mentioned problems, and its purpose is to prevent thermal demagnetization of the magnet of the motor, and to reduce the performance of the shock absorber. Is to prevent.

  In order to achieve the above-described object, the motor of the present invention includes a rotor having a yoke and a magnet attached to the outer periphery of the yoke, and the yoke has at least one through hole opened at both ends thereof. It is characterized by.

  Furthermore, the shock absorber according to the present invention includes a motion conversion mechanism that converts linear motion into rotational motion, and a shock absorber that includes a motor to which the rotational motion is transmitted. The yoke is provided with at least one through hole that opens at both ends of the yoke.

 According to the motor of the present invention, even if the motor is continuously driven or the winding becomes high temperature in a high rotation range, the rotor yoke has a through hole, so that not only the outer peripheral surface of the rotor, Since the heat transmitted from the through hole to the magnet is dissipated, the magnet is prevented from becoming high temperature.

  Therefore, even when the motor is driven for a long time or at a high rotational speed, the temperature of the magnet is prevented from rising, thereby preventing the magnet from demagnetizing.

  Then, since demagnetization of the magnet is prevented during driving of the motor, the performance of the motor is not deteriorated, and stable torque can be generated even if the motor is driven for a long time.

  Further, in the shock absorber of the present invention, since the demagnetization of the magnet is prevented during driving of the motor, the control force including the damping force generated by the shock absorber is stabilized, and the performance of the shock absorber is prevented from being deteriorated. Its function is maintained.

  Furthermore, the yoke is provided with a through hole, and the rotor is lighter than the conventional motor mounted on the shock absorber. Therefore, generation of unnecessary damping force due to moment of inertia can be reduced, and the damping force generated by the shock absorber can be reduced. Controllability is improved, and when the shock absorber is applied to a vehicle, the ride comfort in the vehicle can be improved.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a diagram conceptually illustrating the shock absorber according to the first embodiment. FIG. 2 is a diagram conceptually illustrating a shock absorber according to the second embodiment. FIG. 3 is a diagram conceptually illustrating a shock absorber according to the third embodiment.

  As shown in FIG. 1, the shock absorber D1 in the first embodiment includes a motion conversion mechanism H that converts linear motion into rotational motion, and a motor M1, and specifically, the motion conversion mechanism H is The ball screw nut 1 and a screw shaft 2 screwed to the ball screw nut 1 are configured to convert the linear motion of the ball screw nut 1 and the screw shaft 2 into the rotational motion of the screw shaft 1. The rotational movement of the screw shaft 1 is transmitted to the rotor R of the motor M1, and an induced electromotive force is generated in the winding 13 in the motor M1, thereby causing the motor M1 to regenerate energy and generating an electromagnetic force. The torque that resists the rotation of the rotor R due to the force is used as a damping force that suppresses the rotational motion of the screw shaft 2 and suppresses the linear motion of the ball screw nut 1.

  Further, in the shock absorber D1, as described above, not only the kinetic energy of the linear motion of the ball screw nut 1 and the screw shaft 2 in the axial direction is regenerated to generate a damping force, but also the motor M1 is actively activated. In this case, the buffer D1 also functions as an actuator.

  That is, particularly when the shock absorber D1 actively functions as an actuator, the shock absorber D1 can generate a control force including a damping force, and controls expansion and contraction of the shock absorber D1 so as not to vibrate the vehicle body. For example, it can function as an active suspension.

  Hereinafter, each part will be described in detail. The motor M1 includes a rotor R and a stator S. The rotor R includes a rotor shaft 3, a yoke 4 with a cylindrical wall pressure fixed to the outer periphery of the rotor shaft 3, and a yoke. The rotor R is supported on the upper and lower ends of the rotor R via ball bearings 10 and 11 provided in the case C, and rotates with respect to the case C. It is installed freely.

  Incidentally, the permanent magnet 8 may be composed of a plurality of blocked magnets and adhered to the outer periphery of the yoke 4, or may be formed in an annular shape and divided and magnetized. .

  In addition, the yoke 4 is provided with a plurality of through holes 5 that open at both ends, which are upper and lower ends in FIG.

  On the other hand, the stator S is composed of a cylindrical stator core 12 mounted on the inner periphery of the case C and a winding 13 wound around the stator core 12, and is opposed to the permanent magnet 8 of the rotor R.

  That is, the motor M1 is configured as a so-called brushless motor that generates a rotating magnetic field in the winding 13 of the stator S and rotationally drives the rotor R. In this embodiment, the winding M13 The rotational position detecting means of the rotor R required for generating the rotating magnetic field is the magnetic sensor 14 shown in the figure, and this magnetic sensor 14 does not hinder the rotation of the rotor R on the inner periphery on the upper end side of the case C. The annular plate P is attached to a surface facing the upper end surface of the permanent magnet 8, and for example, an MR element or a Hall element is used.

  In addition to the MR element and Hall element described above, a resolver or the like can be used as the rotational position detecting means.

  Further, a plurality of holes 15 are provided at the lower end in FIG. 1 of the case C, and the inside and outside of the case C are communicated by the holes 15.

  In turn, the motion conversion mechanism H is composed of the ball screw nut 1 and the screw shaft 2 as described above. The ball screw nut 1 is not shown in detail, but the inner periphery of the screw shaft 2 is not shown. A spiral ball holding portion is provided so as to coincide with a spiral screw groove (not shown), and a large number of balls are arranged in the ball holding portion. A passage (not shown) communicating with both ends of the ball holding portion is provided so that the ball can circulate, and when the ball screw nut 1 is screwed onto the screw shaft 2, the screw Since the ball of the ball screw nut 1 is fitted into the helical screw groove of the shaft 2 and the ball itself is rotated by the frictional force with the screw groove of the screw shaft 2 as the screw shaft 2 rotates, rack and pinion, etc. Smooth operation is possible compared to other mechanisms

  The ball screw nut 1 is fitted to the upper end of the cylinder 18 and, for example, one of the vehicle body side member or the vehicle body side member of the vehicle is provided via an eye 19 provided at the lower end of the cylinder 18 in FIG. Since the rotation of the circumferential direction of the ball screw nut 1 is restricted with respect to the screw shaft 2, when the ball screw nut 1 exhibits a linear motion in the vertical direction in FIG. Driven by rotation.

  In other words, the relative movement in the axial direction between the ball screw nut 1 and the screw shaft 2 is converted into the rotational motion of the screw shaft 2 by the above mechanism.

  On the other hand, the upper end of the screw shaft 2 is connected to the rotor shaft 3 of the motor M1, and the case C of the motor M1 is connected to the other of the vehicle body side member or the axle side member of the vehicle. It is interposed between the vehicle body side member and the axle side member.

  The screw shaft 2 and the rotor shaft 3 may be coupled via a coupling or the like, or the screw shaft 2 and the rotor shaft 3 may be integrally formed.

In the shock absorber D1 configured as described above, when the vehicle body side member and the axle side member exhibit relative linear motion by vibration input from the road surface, the screw shaft 2 is rotationally driven. When the rotational motion of 2 is transmitted to the rotor R of the motor M1 and the rotor R of the motor M1 exhibits the rotational motion, the winding 13 in the motor M1 crosses the magnetic field of the permanent magnet 8, and an induced electromotive force is generated. That is, kinetic energy is regenerated, and torque due to electromagnetic force caused by the induced electromotive force acts on the rotor R of the motor M1, and the torque suppresses the rotational movement of the rotor R.

  The action of suppressing the rotational movement of the rotor R is to suppress the rotational movement of the screw shaft 2, and the rotational movement of the screw shaft 2 is suppressed, so that the linear movement of the ball screw nut 1 is suppressed. The shock absorber D1 generates a control force that acts as a damping force in this case by the torque, and absorbs and relaxes vibration energy.

  At this time, when the current is actively supplied to the winding wire 13, the expansion and contraction of the shock absorber D1 can be freely controlled by adjusting the torque acting on the rotor R, that is, the control force of the shock absorber D1 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 D1 variable, or to make the shock absorber D1 function as an actuator.

 Here, when the rotor R is rotationally driven, that is, when the shock absorber D1 expands and contracts, a current normally flows through the winding 13 from an external power source or by induced electromotive force.

  In particular, when the motor M <b> 1 is continuously driven or in a high rotation range, the winding 13 has a high temperature because current continuously flows, and this heat is transmitted to the permanent magnet 8.

 However, since the yoke 4 of the rotor R is provided with the through hole 5, the heat transmitted to the permanent magnet 8 is dissipated not only from the outer peripheral surface of the rotor R but also from the through hole 5, so that the permanent magnet 8 It is prevented that the temperature becomes high.

 The heat is transferred to the gas in the case C and dissipated, but a plurality of holes 15 are provided below the case C in FIG. 1, and the inside and outside of the case C are communicated by the holes 15. Therefore, heat is prevented from being trapped in the case C, and this also prevents the temperature of the permanent magnet 8 from rising.

  Therefore, even when the motor M1 is driven for a long time or at a high rotational speed, the temperature of the permanent magnet 8 that is a magnet is prevented from rising. This prevents the permanent magnet 8 that is a magnet from being demagnetized.

  Then, since the demagnetization of the permanent magnet 8 is prevented during the driving of the motor M1, the performance of the motor M1 is not deteriorated, and a stable torque can be generated even when the motor M1 is driven for a long time. The control force including the damping force generated by the shock absorber D1 is stabilized, the performance deterioration of the shock absorber D1 is prevented, and the function is maintained.

  Although one through hole 5 may be used, it is preferable to provide a plurality of through holes 5 in order to enhance the heat dissipation effect.

  Furthermore, in this case, the yoke 4 is provided with a through hole 5, and the rotor R is lighter than the motor mounted on the conventional shock absorber. Therefore, an unnecessary damping force due to the inertia moment peculiar to the shock absorber D1 of this configuration is obtained. Generation can be reduced.

  Here, the damping force caused by the moment of inertia will be described briefly. The damping force generated by the shock absorber D1 is roughly the moment of inertia of the screw shaft 2, the moment of inertia of the rotor R of the motor M1, and the moment of inertia of the ball screw nut 1. And the sum of the electromagnetic forces generated by the motor M1, and each of the moments of inertia is because the angular acceleration of the rotor R of the motor M1 is proportional to the acceleration of the expansion / contraction motion of the shock absorber D1. Although it increases in proportion to the acceleration of the motion, the inertia moment of the rotor R is relatively large and the influence on the damping force cannot be ignored.

  Since the inertia moment of the rotor R is proportional to the acceleration of the expansion and contraction motion as described above, the shock absorber D1 corresponds to the axial force of the shock absorber D1 input to the shock absorber D1 from the road surface or the like. A damping force that does not depend on the electromagnetic force of the motor M1 is generated. In particular, when a sudden axial force is input, a higher damping force is generated, and the vehicle occupant feels jerky. It will be perceived.

  Therefore, the damping force due to the inertia moment of the rotor R is always generated prior to the damping force depending on the electromagnetic force, and the damping force generated by the inertia moment of the rotor R depending on the acceleration of the expansion and contraction motion of the shock absorber D1. Therefore, the smaller the inertia moment of the rotor R is, the more the influence of the inertia moment on the damping force can be suppressed.

 That is, since the generation of unnecessary damping force due to the moment of inertia of the rotor R can be reduced by reducing the weight of the rotor R, the controllability of the damping force generated by the buffer D1 is improved, and the buffer When D1 is applied to a vehicle, the ride comfort in the vehicle can be improved.

  Subsequently, the shock absorber D2 in the second embodiment will be described, but the same parts as those in the first embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

  The shock absorber D2 in the second embodiment is different from the shock absorber D1 in the first embodiment in its motor part as shown in FIG. 2, specifically, in the second embodiment. In the embodiment, the rotor R2 of the motor M2 of the shock absorber D2 is provided with a plurality of exhaust holes 6 communicating from the outer peripheral side toward the through hole 5.

  Each of these exhaust holes 6 is formed from the outer periphery of the rotor R 2, that is, from the outer periphery side of the permanent magnet 8 toward the yoke 4, and communicates with the corresponding through hole 5.

  Thus, in the motor M2 provided with the exhaust hole 6, the rotor R2 is rotationally driven when the shock absorber D2 expands and contracts, as in the first embodiment. This gas receives a force toward the outer periphery of the rotor R2 by centrifugal force due to the rotation of the rotor R2, and is discharged from the exhaust hole 6.

  Then, the gas flows into the exhaust hole 6 where the atmospheric pressure is reduced by the discharge of the gas through the through hole 5, and the through hole 5 opened at the upper and lower ends of the yoke 4 sucks the exhaust hole 6. Acts as a hole.

  While this gas stays in the through-hole 5 and the exhaust hole 6, it takes away the heat transmitted to the permanent magnet 8 that is a magnet, and is eventually discharged from the exhaust hole 6. The temperature rise of the permanent magnet 8 is prevented.

  Unlike the first embodiment, the gas sucked through the through hole 5 by the exhaust hole 6 can be discharged to the outside of the rotor R2, so that the cooling effect of the permanent magnet 8 is further enhanced. Since the discharged gas is blown directly onto the stator S, the stator S can be cooled.

  The gas sucked into the through-hole 5 is the gas in the case C, but a plurality of holes 15 are provided in the lower part of the case C in FIG. Therefore, heat is prevented from being accumulated in the case C, and the temperature rise of the permanent magnet 8 and the stator S is also prevented by this.

  Accordingly, even in the shock absorber D2 in the second embodiment, the temperature increase of the permanent magnet 8 of the motor M2 is prevented, so that the performance deterioration of the motor M2 is prevented, and as a result, the shock absorber D2 The performance degradation of is prevented.

  Even in the shock absorber D2 in the second embodiment, the moment of inertia of the rotor R2 is reduced in the same manner as in the first embodiment. Therefore, in this respect, the first embodiment It is possible to achieve the same effects as the above.

  Moreover, although the exhaust hole 6 is provided so as to be orthogonal to the outer peripheral surface of the rotor R2 as described above, it may be provided so as to be inclined with respect to the circumferential direction or the axial direction of the rotor R2.

  Finally, the shock absorber D3 in the third embodiment will be described. Also in the third embodiment, the same parts as those in the first embodiment are simply denoted by the same reference numerals, and detailed description thereof is omitted.

  In the shock absorber D3 in the third embodiment, as shown in FIG. 3, the motor portion is different from the shock absorber D1 in the first embodiment, and specifically, in the third embodiment. The configuration of the rotor R3 of the motor M3 in the shock absorber D3 is different.

  Therefore, the above different points will be described in detail. The rotor R3 includes the same rotor shaft 3 as in the first embodiment, a yoke 20, and a coil spring 26 as a fin, and the yoke 20 has a cylindrical shape. The main body 21, lid portions 22 and 23 for closing the open end portions at both ends of the cylindrical main body 21 and connecting the cylindrical main body 21 and the rotor shaft 3, and a plurality of notches 24 provided in the respective lid portions 22 and 23. , 25. In this case, the through hole is formed by the notches 24, 25 and the inside of the cylindrical main body 21.

  Further, a coil spring 26 having an outer diameter substantially the same as the inner diameter of the cylindrical main body 21 is inserted into the cylindrical main body 21 while being sandwiched between the lid portions 22 and 23 in a compressed state.

  When the rotor R3 is driven to rotate, the gas in the cylindrical main body 21 is discharged from one of the notches 24 or 25 because the coil spring 26 is helical, and the gas outside the cylindrical main body 21 is notched. 24 or the other of the notches 25 is sucked into the cylindrical main body 21.

  While this gas stays in the cylindrical main body 21, it takes away the heat transmitted to the permanent magnet 8 that is a magnet and eventually is discharged from one of the notch 24 or the notch 25. The temperature rise of the permanent magnet 8 is prevented.

  Unlike the first embodiment, the coil spring 26 serving as a fin is forcibly discharged to the outside of the cylindrical main body 21, and the cooling effect of the permanent magnet 8 is further enhanced and the gas is notched 25. In this case, the gas sucked into the cylindrical main body 21 is guided into the case C through the hole 15 and passes between the stator S and the outer periphery of the rotor R3 and sucked from the notch 24. On the contrary, when the gas is discharged through the notch 24, the gas sucked into the cylindrical main body 21 through the notch 25 is introduced into the case C through the hole 15 and discharged from the notch 24. The gas passes between the stator S and the outer periphery of the rotor R3, so that the gas passes between the stator S and the outer periphery of the rotor R3 to cool the stator S anyway. But It is a function.

  In addition, the gas sucked into the cylindrical main body 21 is the gas in the case C. A plurality of holes 15 are provided in the lower part of the case C in FIG. 15, it is possible to prevent heat from being accumulated in the case C, and this also prevents the temperature increase of the permanent magnet 8 and the stator S.

  Accordingly, even in the shock absorber D3 in the third embodiment, the temperature increase of the permanent magnet 8 of the motor M3 is prevented, so that the performance deterioration of the motor M3 is prevented, and as a result, the shock absorber D3. The performance degradation of is prevented.

  Even in the shock absorber D3 according to the third embodiment, the moment of inertia of the rotor R3 is reduced as in the first embodiment, and in this respect, the first embodiment It is possible to achieve the same effects as the above.

  Further, in the above description, the fin is the coil spring 26. However, a spiral fin may be formed on the inner periphery of the cylindrical main body 21. There is an advantage that the processing to be formed on the inner periphery is unnecessary, and the manufacturing cost is reduced, and the coil spring 26 is sandwiched between the lid portions 22 and 23 as described above. It is possible to suck and discharge gas efficiently.

  The fins are not necessarily provided on the inner peripheral side of the cylindrical main body 21, and the fins on the outer peripheral side of the rotor shaft 3 may be formed. In this case as well, the fins can be coil springs. .

  Further, as shown in the figure, the yoke 20 is composed of a cylindrical main body 21, lid portions 22 and 23, and notches 24 and 25, but a magnet that is formed into a cylindrical shape by omitting the cylindrical main body 21. May be connected to the rotor shaft 3 by a lid portion similar to the lid portions 22 and 23, and a through hole may be formed by the inside of the magnet and a hole provided in the lid portion.

  Further, in the present embodiment, the lid portions 22 and 23 are formed in an annular shape. However, the lid portions 22 and 23 are connected to the inner peripheral side of the open end of the cylindrical main body 21 and the outer periphery of the rotor shaft 3, respectively. For example, three arms, and in this case, the gap between the arms allows passage of gas, so that this gap functions as a part of the through hole. Become.

  Incidentally, in each of the above-described embodiments, the motion conversion mechanism H is the ball screw nut 1 and the screw shaft 2. However, for example, the pinion side may be connected to a motor as a rack and pinion mechanism.

  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 shock absorber in 1st Embodiment. It is a figure which shows notionally the shock absorber in 2nd Embodiment. It is a figure which shows notionally the shock absorber in 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ball screw nut 2 Screw shaft 3 Rotor shaft 4,20 Yoke 5 Through-hole 6 Exhaust hole 8 Permanent magnet 10 and 11 which are magnets Ball bearing 12 Stator core 13 Winding 14 Magnetic sensor 15 Hole 18 Cylinder 19 Eye 21 Cylindrical main body 22, 23 Lid 24, 25 Notch 26 Coil spring C Case D1, D2, D3 Shock absorber H Motion conversion mechanism M1, M2, M3 Motor R, R2, R3 Rotor S Stator

Claims (10)

A motor comprising a rotor having a yoke and a magnet attached to the outer periphery of the yoke, wherein the yoke is provided with at least one through hole that opens at both ends thereof. The yoke includes a cylindrical main body, a lid portion that closes both ends of the cylindrical main body and connects the cylindrical main body and the rotor shaft, and at least one notch provided in each lid portion. The motor according to claim 1, wherein the motor is formed by a notch and a cylindrical main body. The yoke includes a pair of lid portions that connect the open end portions of both ends of the magnet formed in a cylindrical shape and the rotor shaft, and at least one notch provided in each lid portion. The motor according to claim 1, wherein the motor is formed in a magnet. The motor according to any one of claims 1 to 3, further comprising an exhaust hole that opens from an outer peripheral side of the rotor and communicates with the through hole. The motor according to claim 2, wherein a spiral fin is provided in the through hole. A shock absorber having a motion conversion mechanism for converting linear motion into rotational motion and a motor to which the rotational motion is transmitted, wherein the motor includes a rotor having a yoke and a magnet mounted on the outer periphery of the yoke, and the yoke The shock absorber is characterized in that at least one or more through holes are provided at both ends of the shock absorber. The yoke includes a cylindrical main body, a lid portion that closes both ends of the cylindrical main body and connects the cylindrical main body and the rotor shaft, and at least one notch provided in each lid portion. The shock absorber according to claim 6, wherein the shock absorber is formed by a notch and a cylindrical main body. The yoke includes a pair of lid portions that connect the open end portions of both ends of the magnet formed in a cylindrical shape and the rotor shaft, and at least one notch provided in each lid portion. The shock absorber according to claim 6, wherein the shock absorber is formed in a magnet. The shock absorber according to any one of claims 6 to 8, further comprising an exhaust hole that opens from an outer peripheral side of the rotor and communicates with the through hole. The shock absorber according to claim 7 or 8, wherein a helical fin is provided on the inner peripheral side of the cylindrical main body or the outer peripheral side of the rotor shaft.

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