JP2004011751A - Electromagnetic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To conserve an electromagnetic shock absorber main body, and a stator and a rotor of a motor from the outside, promote the heat dissipation of the motor, prevent the damage owing to the rise in temperature exceeding the rating of the motor, improve the productivity, and reduce the manufacturing cost of the electromagnetic shock absorber. <P>SOLUTION: The electromagnetic shock absorber is comprised of the electromagnetic shock absorber main body D having a ball screw nut 16 and a screw shaft 15 rotatably screwed in the ball screw nut 16, and a motor connected to the screw shaft 15. In the electromagnetic shock absorber, linear movement of the ball screw nut 16 is converted into rotational movement of the screw shaft 15, electromagnetic force is generated in the motor by transmitting the rotational movement to a shaft 6 of the motor, and the torque against the rotation of the shaft 6 owing to the electromagnetic force is used as damping force inhibiting the linear movement of the ball screw nut 16. An integrated outer cylinder 1 overlying both the electromagnetic shock absorber main body and the motor is provided, and the outer cylinder doubles as a frame overlying the stator and the rotor of the motor. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention has a mechanism for converting the expansion and contraction movement of an electromagnetic shock absorber into a rotational movement of a motor by rotatably screwing a ball screw into a ball nut, and using the electromagnetic force of the motor as a damping force. The present invention relates to a shock absorber, and more particularly to an improvement of a motor frame and the electromagnetic shock absorber outer cylinder.
[0002]
[Prior art]
In general, a suspension in which a hydraulic shock absorber is interposed between a vehicle body and an axle in parallel with a suspension spring is known. This suspension suspends the vehicle body and attenuates the input of vibrations and the like from the road surface to the vehicle. The ride height and the maneuverability are improved, or the displacement of the vehicle body is suppressed to keep the vehicle height constant.
[0003]
On the other hand, a vehicle that incorporates an electromagnetic shock absorber provided with a hydraulic shock absorber and the like in a part of the suspension and generates an electromagnetic force by flowing a current to the motor when the vehicle body changes, and uses this electromagnetic force as a damping force that suppresses the vehicle body change Suspensions are also known, for example, as disclosed in JP-A-5-44758.
[0004]
However, a suspension using the above-described hydraulic shock absorber requires oil while providing high damping force, and requires a sealing mechanism and a complicated valve mechanism for preventing leakage of the oil.
[0005]
Similarly, a suspension using an electromagnetic shock absorber requires a power supply, a controller, and the like, has a complicated structure, and is disadvantageous in terms of cost.
[0006]
Therefore, a new electromagnetic shock absorber that does not require oil, air, a power supply, and the like has recently been studied, and a paper thereof has been published.
[0007]
The basic structure of this electromagnetic shock absorber is, for example, as shown in the model of FIG. 2, a ball screw nut 16, a flange 34 holding the ball screw nut 16, a flange 37 to which an eye bracket 38 is fixed, A guide rod 36 connecting the flanges 34 and 37; a screw shaft 15 rotatably screwed into the ball screw nut 16; and a motor 27 connected to the upper end of the screw shaft 15 via a coupling 26 and a shaft 27a. It is composed of
[0008]
Here, as the motor as the electromagnetic force generating source, various motors, for example, a DC motor or an induction motor can be used.For example, taking a DC motor as an example, although not particularly shown, if it is a DC brushed motor, A plurality of permanent magnets for generating a magnetic field, a solenoid, an armature, a yoke, a commutator, a frame, and a shaft in the motor 27. An armature is provided on the shaft to form a solenoid by winding a conductive wire. In addition, the solenoid generates an induced electromotive force when the solenoid crosses the magnetic field generated by the permanent magnet due to the rotation of the shaft.
[0009]
When this electromagnetic shock absorber is used as a suspension, for example, by being interposed between the vehicle body and the axle, the upper end of the electromagnetic shock absorber is connected via a bracket 40 fixed to a flange 28 provided on the motor 27. And the lower end of the electromagnetic shock absorber is connected to the axle side via the eye bracket 38.
[0010]
In this case, the lower end of the motor 27 is connected to the flange 32 via the flange 30 and the connecting rod 31, and a ball bearing 43 is fixed to the inner periphery of the flange 32. Is rotatably inserted.
[0011]
Further, the flange 32 is connected to the flange 35 by a connecting rod 33, and the guide rod 36 is slidably inserted into a hole provided in the flange 35, and only the linear movement of the ball screw nut 16 is allowed. It is supposed to be.
[0012]
According to the concept of the suspension using the electromagnetic shock absorber, for example, when the ball screw nut 16 linearly moves in the direction of arrow a due to the vibration input from the road surface, the screw shaft 15 in the ball screw nut 16 becomes the ball screw nut 16. It is guided by the inner ball and the threaded groove 15a on the outer periphery of the screw shaft 15 and converted into a rotational motion.
[0013]
For this reason, the rotational motion of the screw shaft 15 is transmitted as the rotational motion of the shaft 27a in the direction of the arrow b via the coupling 26 attached to the upper end of the screw shaft 15, thereby generating an induced electromotive force in the motor 27. Although not particularly shown, if the electrodes of the motor 27 are short-circuited without using a power supply or connected to a control circuit so as to obtain a desired electromagnetic force, the solenoid in the motor 27 causes the above-mentioned induced electromotive force. Current flows, and the motor 27 generates an electromagnetic force.
[0014]
At this time, if each electrode of the motor 27 is short-circuited or connected to a control circuit so that an electromagnetic force against the rotation of the shaft 27a is generated, a torque against the rotation caused by the electromagnetic force is generated. Thus, the rotation of the shaft 27a of the motor 27 is suppressed.
[0015]
Then, suppressing the rotation of the shaft 27 a means suppressing the rotation of the screw shaft 15, and thus the torque acts as a damping force for suppressing the linear movement of the ball screw nut 16.
[0016]
[Problems to be solved by the invention]
When this electromagnetic shock absorber is actually applied to a vehicle, the shock absorber is usually disposed between the vehicle body and the axle, but there are various problems as described below.
[0017]
That is, in the above-described configuration of the electromagnetic shock absorber, since the motor 27, the screw shaft 15, and the ball screw nut 16 are in a bare state, the motor 27, the screw shaft 15, and the ball screw nut 16 are not isolated from splashes of rain, mud, stones, etc. from outside the vehicle body. For example, rainwater or muddy water enters the motor 27, and the motor 27 is leaked and damaged, or a stone or the like hits the motor 27, the screw shaft 15, and the ball screw nut 16, and is deformed or damaged. Therefore, the function of the motor 1 or the like may be impaired.
[0018]
Therefore, an outer cylinder as a cover for covering the motor 27, the screw shaft 15, and the ball screw nut 16 is required over the entire electromagnetic shock absorber.
[0019]
However, the motor 27 generally includes a stator, a rotor, and a frame that covers the stator. Therefore, if the motor is covered with an outer cylinder, an electromagnetic shock absorber is arranged between the lower surface of the vehicle body and the axle. In such a case, the space between the lower surface of the vehicle body and the axle is limited depending on the type of the vehicle, and the space where the motor 27 can be accommodated in the outer cylinder cannot necessarily be increased.
[0020]
Then, a current flows through the solenoid in the motor 27 due to the rotational motion transmitted from the shaft screw 15 in the motor 27, and the current generates heat due to the current, but as described above. Since the motor 27 as an independent component is housed in a not-so-large outer cylinder, heat radiation of the motor 27 is hindered, heat is trapped in the motor 27, and the temperature of the motor 27 itself rises. .
[0021]
Further, when the temperature of the motor 27 rises and exceeds the temperature rating of the motor 27, the heat generated by the motor itself deteriorates the insulation property due to chemical change of the insulation coating of the conductor forming the solenoid of the motor, and as a result, There is a fear that the motor itself may be damaged due to electric leakage or the like.
[0022]
Further, when the motor 27 is an independent part, when the motor 27 is screwed into the electromagnetic shock absorber main body, the number of parts such as bolts, nuts, and a bracket for the motor increases, and a process of processing the electromagnetic shock absorber is also required. As the number increases, productivity and production costs deteriorate.
[0023]
Therefore, an object of the present invention is to protect the electromagnetic shock absorber main body, the stator and the rotor of the motor from the outside, promote heat radiation of the motor, and prevent damage due to a temperature rise exceeding the rating of the motor. Another object of the present invention is to improve the productivity of the electromagnetic shock absorber and reduce the production cost of the electromagnetic shock absorber.
[0024]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has an electromagnetic shock absorber main body having a ball screw nut and a screw shaft rotatably screwed in the ball screw nut, and a motor coupled to the screw shaft. Then, the linear motion of the ball screw nut is converted into the rotational motion of the screw shaft, and this rotational motion is transmitted to the shaft of the motor to generate an electromagnetic force in the motor, which resists the rotation of the shaft due to the electromagnetic force. An electromagnetic shock absorber that uses the torque generated as a damping force to suppress the linear movement of a ball screw nut, comprises an integral outer cylinder that covers both the electromagnetic shock absorber main body and the motor, and the outer cylinder includes a motor stator and a rotor. Characterized in that it also serves as a frame that covers
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on the embodiment shown in the drawings.
[0026]
The basic form of the electromagnetic shock absorber according to the present invention is an electromagnetic shock absorber having a hollow rod 17, a ball screw nut 16 provided at an end of the hollow rod 17, and a screw shaft 15 rotatably screwed into the ball screw nut 16. The main body D, the stator and the rotor M of the motor coupled to the screw shaft 15, and the outer cylinder 1 that covers both the electromagnetic buffer main body D and the stator and the rotor M of the motor.
[0027]
Hereinafter, a more detailed structure will be described.
[0028]
The stator and the rotor M of the motor are DC brush motors, and include a plurality of permanent magnets 4a and 4b for generating a magnetic field, a solenoid 2a, an armature 2, a commutator 3, a brush 5, and a brush holder. 7 and a shaft 6 and are inserted into the outer cylinder 1.
[0029]
The permanent magnets 4a and 4b are mounted in the outer cylinder 1 so as to face each other, but may be two or more if they are mounted so as to generate a magnetic field.
[0030]
While the upper and lower ends of the shaft 6 are rotatably inserted into the outer cylinder 1 via ball bearings 9 and 10, an armature 2 is provided on the outer periphery of the shaft 6 and a conductive wire is wound around the shaft 6 to form a solenoid 2a. The plurality of conductive wires 2a (not shown) are connected to a commutator 3 provided above the shaft 6, and the commutator 3 is connected to the outer cylinder 1 via a brush holder 7 provided on the side thereof. The brush 5 is in contact with the connected brush 5, and the brush 5 is connected to a lead wire 8.
[0031]
A cap 10 is coupled to the upper end of the outer cylinder 1 to prevent rain and muddy water from entering the outer cylinder 1.
[0032]
Further, the permanent magnets 4a and 4b are coupled to the upper inner periphery of the outer cylinder 1 by matching the position where the armature 2 is accommodated in the outer cylinder 1, whereby a magnetic field is applied to the armature 2. It will be confined. In this case, the outer cylinder 1 has a function as a yoke in addition to a function as a frame that covers the stator and the rotor M of the motor.
[0033]
The lead wires 8 are connected to a control circuit or the like (not shown) or are directly connected to the respective electrodes (not shown) to form a closed circuit. It is necessary to generate a torque against the rotation of the shaft 6 to generate an electromagnetic force on the motor M, and to adjust the motor M to obtain a desired damping force.
[0034]
In this case, if there is no need to provide a control circuit, there is no need to provide a lead wire outside the outer cylinder 1, and the above-described electrodes may be short-circuited inside the outer cylinder 1. Holes may not be provided.
[0035]
In this embodiment, a case where a DC brush motor is used as the motor has been described, but a DC brushless motor, an AC motor, or an induction motor may be used.
[0036]
Further, a permanent magnet may be fixed to the shaft 6 and a solenoid may be connected to the inner periphery of the cover 1.
[0037]
Next, the shock absorber main body D will be described.
[0038]
The electromagnetic shock absorber main body D has a hollow rod 17 connected to the axle side via an eye bracket (not shown), a ball screw nut 16 connected to an upper end of the hollow rod 17, and a rotation inside the ball screw nut 16. The screw shaft 15 is freely screwed.
[0039]
The hollow rod 17 is vertically slidably inserted into the outer cylinder 1, and the lower end of the hollow rod 17 is connected to an axle via the eye bracket 10.
[0040]
Here, although the structure of the ball screw nut 16 is not particularly shown, for example, a helical ball holding portion is provided on the inner periphery of the ball screw nut so as to match the helical screw groove of the screw shaft. A large number of balls are arranged in the holding portion, and a passage communicating with both ends of the spiral holding portion is provided inside the ball screw nut so that the balls can circulate, When the screw shaft is screwed into the ball screw nut, the ball of the ball screw nut fits into the helical screw groove of the screw shaft, and the ball itself rotates with the screw groove of the screw shaft with the rotation of the screw shaft. Because of the rotation by the frictional force, smooth operation is possible as compared with a mechanism such as a rack and pinion.
[0041]
As described above, the ball screw nut 16 is rotatably mounted on the screw shaft 15 along the screw groove, and when the ball screw nut 16 makes a linear motion in the vertical direction, the ball of the ball screw nut 16 moves in the vertical direction. At this time, since the ball moves along the spiral screw groove of the screw shaft 15, the screw shaft 15 is forcibly driven to rotate.
[0042]
That is, the linear motion of the ball screw nut 16 is converted into the rotary motion of the screw shaft 15 by the above mechanism, and the linear motion of the hollow rod 17 is converted into the rotary motion of the screw shaft 15 by the above configuration. .
[0043]
The mechanism for converting the linear movement of the hollow rod 17 into the rotational movement is preferably the above-described mechanism. However, a mechanism having the same effect may not be provided by the combination of the ball screw nut 16 and the screw shaft 15.
[0044]
The upper part of the screw shaft 15 is rotatably inserted into the inner periphery of a ball bearing 11 attached to the outer cylinder 1 via a bearing holding member, and the upper end thereof is connected to the shaft 6 of the motor. ing.
[0045]
Accordingly, since the screw shaft 15 is rotatably supported by the ball bearing 11 and the ball screw nut 16, the screw shaft 15 can smoothly rotate.
[0046]
The linear motion of the ball screw nut 16 is converted into the rotary motion of the screw shaft 15 by the above mechanism, and the linear motion of the hollow rod 17 is converted into the rotary motion of the screw shaft 15 by the above configuration.
[0047]
That is, the rotational movement of the screw shaft 15 is transmitted to the shaft 6 of the motor.
[0048]
The above-described mechanism is preferable as a mechanism for converting the linear motion of the hollow rod 17 into a rotary motion. However, any mechanism having the same effect may be used without depending on the combination of the ball screw nut 16 and the screw shaft 15. As a method of transmitting the rotational movement of the screw shaft 15 to the shaft 6, a planetary gear or a torsion bar may be used in addition to the direct connection.
[0049]
When a planetary gear is used, a desired damping force can be obtained without changing a torque characteristic caused by an electromagnetic force generated by a motor by setting a proper gear ratio.
[0050]
With the above configuration, the stator, the rotor M, and the electromagnetic shock absorber main body D of the motor are all housed in the outer cylinder 1.
[0051]
Therefore, compared with the case where the motor M is attached to the electromagnetic shock absorber main body D as an independent part, it is not necessary to use a bracket for mounting the motor M on the main body D, bolts, nuts, and the like. Work such as assembling can be omitted, productivity can be improved, and production cost can be reduced.
[0052]
Further, as described above, no special parts are required for mounting the motor, so that the durability is further improved.
[0053]
Further, since rain, muddy water, stepping stones, etc. are prevented from directly hitting the stator and the rotor M of the motor, the motor can be prevented from being damaged by them.
[0054]
Subsequently, the operation will be described.
[0055]
When an impact such as a thrust input from the road surface or vibration acts on the hollow rod 17 during running of the vehicle, the hollow rod 17 linearly moves in the expansion and contraction direction along the outer cylinder 1. This linear motion is converted into a rotational motion of the screw shaft 15 by a ball screw mechanism of the ball screw nut 16 and the screw shaft 15.
[0056]
Then, the rotational movement of the screw shaft 15 is transmitted to the shaft 6 because the screw shaft 15 and the shaft 6 are connected.
[0057]
When the shaft 6 of the motor exhibits a rotational motion, the solenoid of the armature 2 attached to the shaft 6 also rotates at the same time, and the solenoid crosses the magnetic field of the permanent magnets 4a and 4b, generating an induced electromotive force. As described above, each electrode of the motor is short-circuited, and the current flows through the solenoid so as to generate torque against the rotation of the shaft 6 due to the electromagnetic force of the motor. The torque against the rotation suppresses the rotational movement of the shaft 6.
[0058]
The function of suppressing the rotational movement of the shaft 6 works to suppress the rotational movement of the screw shaft 15 because the shaft 6 is connected to the screw shaft 15.
[0059]
Then, the torque caused by the electromagnetic force of the motor suppresses the rotational movement of the screw shaft 15, and thus acts as a damping force that suppresses the linear movement of the hollow rod 17 in the expansion and contraction direction along the outer cylinder 1. To absorb and reduce the impact energy of the vehicle, improve the riding comfort of the vehicle, and improve the operability.
[0060]
As described above, a function as an electromagnetic shock absorber can be exhibited by a series of operations. However, a load such as a thrust input from the road surface is constantly applied to the hollow rod 17 during running of the vehicle.
[0061]
The rotational motion of the screw shaft 15 due to this load is transmitted to the motor shaft 6 as described above. However, since the current frequently flows through the solenoid of the motor, the motor itself generates heat. appear.
[0062]
Then, the temperature of the motor itself increases, but as described above, the frame of the motor is the outer cylinder 1 and there is no frame that covers the motor separately provided on the motor itself. Is transmitted to the outer cylinder 1 and can radiate heat.
[0063]
Here, the outer cylinder 1 is sufficiently longer than the motor, and when the electromagnetic shock absorber is particularly applied to a vehicle, the electromagnetic shock absorber is attached between the axle and the vehicle body. The wind hits the outer cylinder 1 and heat can be dissipated effectively.
[0064]
【The invention's effect】
As described above, the present invention has the following effects because the outer cylinder also serves as the frame of the motor.
[0065]
(1) Since there is no separate frame in the motor itself, heat generated by the motor can be prevented from being trapped in the motor.
[0066]
(2) Further, although the heat generated by the motor is transmitted to the outer cylinder, the outer cylinder can effectively radiate the heat.
[0067]
(3) Accordingly, it is possible to prevent the temperature of the motor itself from rising, so that it is possible to prevent the insulation from deteriorating due to a chemical change or the like of the insulating film of the conductor forming the solenoid of the motor.
[0068]
(4) Then, it is possible to prevent electric leakage of the motor and the like, so that damage to the motor itself can be suppressed.
[0069]
(5) The motor does not have to be attached to the electromagnetic shock absorber as an independent part, and since the motor and the electromagnetic shock absorber are integrated, the durability against the impact from a road surface or the like is better than before.
[0070]
(6) Compared to a case where the motor is an independent part, parts such as a bracket, a bolt and a nut for attaching the motor to the electromagnetic shock absorber main body are not required, so that the number of parts can be reduced.
[0071]
(7) Therefore, assembling and processing are facilitated, so that productivity can be improved.
[0072]
(8) Further, since the number of parts is reduced, the number of processing steps can be reduced, and the productivity is improved, so that the production cost can be reduced.
[0073]
(9) Since the motor and the shock absorber main body are covered with the outer cylinder, the important parts for performing the function as the electromagnetic shock absorber, that is, the motor, the screw shaft, the ball screw nut, and the power transmission means are provided with rain, Since muddy water, stepping stones and the like are prevented from directly hitting the portion, it goes without saying that the portion can be protected.
[Brief description of the drawings]
FIG. 1 is a side sectional view of an electromagnetic shock absorber according to the present invention.
FIG. 2 is a side view of a conventional electromagnetic shock absorber.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Outer cylinder 2 Armature 2a Solenoid 3 Commutator 4a, 4b Permanent magnet 5 Brush 6 Shaft 7 Brush holder 8 Lead wire 15 Screw shaft 16 Ball screw nut D Electromagnetic shock absorber body M Motor

Claims (1)

An electromagnetic shock absorber main body having a ball screw nut and a screw shaft rotatably screwed into the ball screw nut, and a motor coupled to the screw shaft, wherein the linear movement of the ball screw nut is controlled by the screw shaft. The motor converts the rotational motion into a rotational motion, and transmits the rotational motion to a motor shaft to generate an electromagnetic force. The torque against the rotation of the shaft due to the electromagnetic force suppresses the linear motion of the ball screw nut. In an electromagnetic shock absorber used as a damping force, an integral outer cylinder that covers both the electromagnetic shock absorber main body and the motor is provided, and the outer cylinder also serves as a frame that covers a stator and a rotor of the motor. Electromagnetic shock absorber.

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