JP7121671B2 - Electromagnetic buffer - Google Patents

Description

The present invention relates to an electromagnetic shock absorber.

An electromagnetic shock absorber has, for example, a cylindrical linear motor, and uses the thrust generated by the linear motor as a damping force for suppressing vibration of the vehicle body, or as a control force for controlling the attitude of the vehicle body.

However, with such an electromagnetic shock absorber, since it is difficult to suppress the vibration of the heavy vehicle body with only the thrust of the linear motor, a hydraulic damper is provided to compensate for the lack of thrust.

Specifically, the electromagnetic shock absorber has a linear motor arranged in parallel with the hydraulic damper on the outer periphery of the hydraulic damper (see, for example, Patent Document 1). The linear motor in this electromagnetic shock absorber has an annular permanent magnet laminated on the outer circumference of the inner casing forming the outermost shell of the hydraulic damper, and an outer ring covering the outer circumference of the permanent magnet at the tip of the piston rod of the hydraulic damper. It is composed of a coil provided on the inner circumference of the casing.

The electromagnetic shock absorber configured in this way has a hydraulic damper in parallel with the linear motor, and the thrust generated by the linear motor and the damping force generated by the hydraulic damper suppress the vibration of the vehicle body. there is

JP 2005-240984 A

A conventional electromagnetic shock absorber has a hydraulic damper that is separate from the linear motor, and since the cylindrical linear motor is provided on the outer periphery of the hydraulic damper, it becomes large in the radial direction, so it cannot be mounted on the vehicle. The weight increases as well as the strength deteriorates.

In addition, since the hydraulic damper is covered with the linear motor, the hydraulic damper is not exposed to the wind while the vehicle is running, which deteriorates the cooling performance of the working oil of the hydraulic damper.

In addition to the hydraulic damper seal, the linear motor also needs a seal to prevent dust and water from entering the linear motor. , the cost increases.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an electromagnetic shock absorber that can be mounted on a vehicle without impairing its cooling performance, can be reduced in weight and cost, and can achieve smooth expansion and contraction.

In order to achieve the above object, the electromagnetic shock absorber of the present invention comprises a non-magnetic cylinder, a piston rod movably inserted into the inner circumference of the cylinder, a piston rod slidably inserted into the cylinder and a piston rod. A piston provided on the rod and partitioning the inside of the cylinder into an expansion side chamber and a compression side chamber, a cylindrical mover attached to the piston rod and housed in the cylinder, and a cylinder provided on the outer periphery of the cylinder and facing the mover a linear motor having a stator, a working fluid filled in the expansion side chamber and the compression side chamber, a damping passage connecting the expansion side chamber and the compression side chamber, and a resistance to the flow of the working fluid passing through the passage. a damping valve; The electromagnetic shock absorber constructed in this way is composed of a hydraulic damper composed of a cylinder, a piston rod, a piston, a damping passage, and a damping valve, and a linear motor composed of a mover and a stator. The movable element of the linear motor is accommodated in the hydraulic damper, and the stator is mounted on the outer circumference of the cylinder.

In the electromagnetic shock absorber, if the flow rate passing through the passage is set to Q and any value greater than 1 is set to α, the pressure loss that occurs with respect to the flow rate that the damping valve passes is set to be proportional to Q ^α . may be The electromagnetic shock absorber configured in this way can suppress the reduction in the thrust due to the damping valve when functioning as an actuator, and compensates for the reduction in the thrust of the linear motor with the damping force exerted by the damping valve when functioning as a damper. A damping force suitable for the vehicle can be exhibited.

Furthermore, the electromagnetic shock absorber includes a magnetic field magnet having a plurality of annular permanent magnets mounted on the outer circumference of a cylinder in which the stator is laminated along the axial direction, and a cylindrical cover fitted to the outer circumference of the magnetic field magnet. You may have a body. According to the electromagnetic shock absorber configured in this way, it is possible to protect the permanent magnets and ensure the strength of the electromagnetic shock absorber. In addition, when the cover body is used as a back yoke, the thrust of the linear motor can be improved.

Further, the electromagnetic shock absorber may include a free piston that is slidably inserted into the cylinder to form an air chamber adjacent to the compression side chamber in the cylinder. In this case, the linear motor is integrated with the hydraulic damper. Even with an indivisible configuration, the volume can be compensated for when the piston rod moves in and out of the cylinder.

Further, the electromagnetic shock absorber has a hollow portion in which the piston rod communicates with the compression side chamber, and is slidably inserted into the hollow portion to divide the hollow portion into a liquid chamber and an air chamber, which communicate with the compression side chamber. A free piston may be provided. According to the electromagnetic shock absorber configured in this way, a long stroke length can be ensured, so that when the mover is an armature, the total length of the mover can be increased and the thrust of the linear motor can be increased.

Further, the electromagnetic shock absorber includes an outer tube that covers the outer circumference of the stator and forms a reservoir between itself and the stator, a discharge passage that communicates the compression side chamber and the reservoir, and a discharge passage from the compression side chamber to the reservoir via the discharge passage. A base valve that allows only the flow of the working liquid in the direction toward the pressure side chamber and provides resistance to the flow, and a suction passage that allows only the flow of the working liquid from the reservoir to the pressure side chamber. Further, the electromagnetic shock absorber includes a tank provided on the side of the cylinder and having a reservoir therein, a discharge passage communicating between the compression side chamber and the reservoir, and a base that provides resistance to the flow of the working fluid passing through the discharge passage. It may comprise a valve and a suction passage that only allows the working fluid to flow from the reservoir to the pressure side chamber. Since the electromagnetic shock absorber configured in this way does not require an air chamber in the cylinder, it is possible to secure a long stroke length, and when the mover is used as an armature, the overall length of the mover can be lengthened. can be increased, and even if the linear motor is integrally formed with the hydraulic damper, the volume can be compensated for when the piston rod moves in and out of the cylinder.

Further, in the electromagnetic shock absorber, the passage may communicate the expansion side chamber and the compression side chamber through the piston rod, and the damping valve may be provided inside the piston rod and on the inner peripheral side of the mover. In the electromagnetic shock absorber configured in this way, even when adopting a damping valve that requires a space in the radial direction, the damping valve is arranged on the inner peripheral side of the mover, so it is easy to secure the stroke length. Become.

The electromagnetic shock absorber may have a connecting portion that connects the cylinder and the tank, and the base valve may be provided in the connecting portion or the tank. .

According to the electromagnetic shock absorber of the present invention, it is possible to improve mountability on a vehicle, reduce weight and cost, and achieve smooth telescopic operation.

1 is a longitudinal sectional view of an electromagnetic shock absorber according to a first embodiment; FIG. FIG. 4 is a diagram showing pressure loss characteristics of a damping valve; It is a longitudinal cross-sectional view of the electromagnetic shock absorber in the 1st modification of 1st embodiment. FIG. 4 is a diagram showing the characteristics of the force generated with respect to the piston speed of the electromagnetic shock absorber of the first embodiment; It is a longitudinal cross-sectional view of the electromagnetic shock absorber in the second modification of the first embodiment. It is a longitudinal cross-sectional view of the electromagnetic shock absorber in the 3rd modification of 1st embodiment. It is a longitudinal cross-sectional view of the electromagnetic shock absorber of 2nd embodiment. It is a longitudinal cross-sectional view of the electromagnetic shock absorber in the 1st modification of 2nd embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on embodiments shown in the drawings. It should be noted that configurations common to the electromagnetic buffers of the embodiments described below are denoted by the same reference numerals, and in order to avoid duplication of description, the configuration described in the description of the electromagnetic buffer of one embodiment A detailed description will be omitted in the description of the electromagnetic shock absorbers of other embodiments.

<First embodiment>
The electromagnetic shock absorber D1 in the first embodiment comprises, as shown in FIG. A piston 3 which is movably inserted and provided in the piston rod 2 to divide the inside of the cylinder 1 into an expansion side chamber R1 and a compression side chamber R2; A linear motor LM having a cylindrical stator S provided on the outer periphery and facing the mover M, hydraulic oil as a hydraulic fluid filled in the growth side chamber R1 and the compression side chamber R2, and the growth side chamber R1 and the compression side It comprises a damping passage P that communicates with the chamber R2 and a damping valve V that gives resistance to the flow of hydraulic oil passing through the damping passage P.

Each part of the electromagnetic shock absorber D1 will be described in detail below. The cylinder 1 is cylindrical and made of a non-magnetic material, and on the outer circumference of the cylinder 1, a bag as a cylindrical cover made of a soft magnetic material forms an annular gap with the cylinder 1. A yoke 4 is provided. An annular rod guide 5 is attached to the upper end of the back yoke 4 in FIG. 1 to fit the upper end of the cylinder 1 in FIG. A cap 6 that fits in is attached. Note that the cap 6 is provided with a bracket 6a that enables attachment to the vehicle.

The piston rod 2 is inserted through the inner periphery of the rod guide 5 and is movably inserted into the cylinder 1, and the piston 3 is provided on the outer periphery of the tip. Although not shown, the base end of the piston rod 2, which is the upper end in FIG. 1, is provided with a bracket that enables attachment to a vehicle. A sealing member 5a is provided on the inner periphery of the rod guide 5, and the inside of the cylinder 1 is liquid-tightly sealed.

The piston 3 is slidably inserted into the cylinder 1, and divides the inside of the cylinder 1 into an expansion side chamber R1 and a compression side chamber R2. A free piston 7 is slidably inserted in the inner periphery of the cylinder 1 in the lower part in FIG. 1, and an air chamber G adjacent to the pressure-side chamber R2 is formed below the pressure-side chamber R2. , the expansion side chamber R1 and the compression side chamber R2 are filled with hydraulic oil as a hydraulic fluid. The hydraulic liquid may be water, aqueous solution, or any other liquid other than hydraulic oil as long as the damping valve V can generate a damping force.

A cylindrical armature as a mover M is attached to the outer periphery of the piston rod 2 . Further, a damping passage P is provided that opens from the side portion above the mover M of the piston rod 2 in FIG. The damping passage P communicates the expansion side chamber R1 and the compression side chamber R2. An orifice is provided as a damping valve V in the middle of the damping passage P. As shown in FIG. In the present embodiment, the damping valve V is defined by Q as the flow rate of the hydraulic fluid passing through it, PL as the pressure loss generated with respect to the flow rate through which the damping valve V passes, and α as any value greater than 1. Assuming that the coefficient of is β, the pressure flow characteristic of the damping valve V is set to be P=β× ^Qα as shown in FIG. That is, the pressure loss PL generated with respect to the flow rate through which the damping valve V passes is set to be proportional to ^Qα .

In addition to the orifice, the damping valve V may be a choke or a leaf valve, or may be a damping force adjustment valve capable of adjusting the damping force. When the damping valve V is used as a damping force adjusting valve, the damping valve V includes, for example, a valve seat provided in the middle of the damping passage P provided in the piston rod 2, a A drive source for driving the body toward or away from the valve seat or an urging force generating source capable of adjusting the urging force for pressing the valve body against the valve seat is provided to make the flow passage area or the valve opening pressure variable. It is sufficient if the valve or the like is used.

When the damping valve V is used as a damping force adjusting valve, it may be provided inside the piston rod 2 and on the inner peripheral side of the mover M. As shown in FIG. If the damping valve V is a damping force adjusting valve, it is often necessary to secure a large space in the piston rod 2 in the radial direction. In some cases, the rod 2 needs to have a large-diameter portion at a position away from the mover M. The outer diameter of the mover M is larger than that of the piston rod 2. If the piston rod 2 is provided with a large-diameter portion other than the portion where the mover M is attached, the axis from this large-diameter portion to the mover M The directional length reduces the stroke length of the piston rod 2 . Therefore, when the damping valve V is used as a damping force adjusting valve, if it is arranged inside the piston rod 2 and on the inner peripheral side of the mover M, there is an advantage that it becomes easy to secure the stroke length of the electromagnetic shock absorber D1. .

When the damping valve V is used as a damping force adjusting valve, the piston rod 2 is used as the driving source or biasing force generating source so as not to be affected by the magnetic field generated by the energization of the mover M or the magnetic field generated by the magnetic field described later. is provided at the upper end in FIG. 1, and the piston rod 2 is cylindrical, and the power of the drive source or biasing force generation source is transmitted to the valve body via the control rod inserted through the piston rod 2. may Further, when the damping valve V is a damping force adjusting valve, a rotary valve as disclosed in Japanese Patent Laid-Open No. 2009-287764 may be used as an example.

Further, in the present embodiment, all damping passages P are provided in the piston rod 2, but like the electromagnetic shock absorber D1-1 of the first modification of the _first embodiment shown in FIG. , may form a damping passage P. Specifically, a gap is provided between the mover M and the piston 3, holes 3a and 3b are provided through the piston 3 in the axial direction, and the piston rod 2 is opened between the piston 3 and the mover M. Then, a hole 2a leading to the expansion side chamber R1 is provided. These holes 2a, 3a, and 3b may be used as damping passages P. In this case, a leaf valve 8 stacked on the upper end of the piston 3 in FIG. 3 for opening and closing the hole 3a and a leaf valve 9 stacked on the lower end of the piston 3 in FIG. Valves 8 and 9 may be damping valves V. FIG. In this way, when the electromagnetic shock absorber D1-1 expands, the leaf valve ₈ closes the hole 3a and the leaf valve 9 opens the hole 3b to give resistance to the flow of hydraulic oil, and when the electromagnetic shock absorber _D1-1 contracts, The leaf valve 9 closes the hole 3b and the leaf valve 8 opens the hole 3a to give resistance to the flow of hydraulic oil. Therefore, by doing so, the damping force can be tuned independently when the electromagnetic shock absorber _D11 is extended and when it is retracted.

The mover M consists of a core 11 mounted on the outer circumference of the piston rod 2, and windings 12 mounted in slots 11a, which are annular grooves arranged on the outer circumference of the core 11 at a predetermined pitch in the axial direction. and is configured as an armature in the present embodiment. The windings 12 attached to the slots 11a are three-phase windings of U-phase, V-phase and W-phase. An annular gap is provided between the outer circumference of the core 11 and the inner circumference of the cylinder 1 to prevent direct interference between the core 11 and the cylinder 1 .

A plurality of annular permanent magnets 10a and 10b are laminated on the outer periphery of the cylinder 1, and these permanent magnets 10a and 10b are accommodated in an annular gap between the cylinder 1 and the back yoke 4. there is In the present embodiment, the permanent magnets 10a and 10b and the back yoke 4 constitute a magnetic field that alternately applies S-pole and N-pole magnetic fields to the inner peripheral side of the cylinder 1. A stator S is formed. Since the cylinder 1 is made of a non-magnetic material, the magnetic field generated by the magnetic field can permeate the cylinder 1 and act on the inside of the cylinder 1 .

In the present embodiment, the permanent magnet 10a serving as the main magnetic pole and the permanent magnet 10b serving as the auxiliary magnetic pole are laminated in the Halbach arrangement so that the S pole and the N pole appear alternately in the axial direction on the inner peripheral side of the cylinder 1. ing. In FIG. 1, the triangular marks on the permanent magnet 10a of the main pole and the permanent magnet 10b of the subsidiary pole indicate the direction of magnetization, and the direction of magnetization of the permanent magnet 10a of the main pole is the radial direction. The direction of magnetization of the permanent magnet 10b of the secondary magnetic pole is the axial direction. The axial length of the permanent magnet 10a of the main magnetic pole is longer than the length of the permanent magnet 10b of the sub-magnetic pole in the axial direction. Since the resistance can be reduced and the magnetic field acting on the core 11 can be increased, the thrust of the linear motor LM can be improved. The permanent magnets 10a and 10b do not need to be arranged in the Halbach arrangement, since the magnetic field should be applied so that the S pole and the N pole alternately appear on the inner peripheral side of the cylinder 1 in the axial direction. In this case, the permanent magnets 10a and 10b may have the same length in the axial direction, have different magnetic poles on their inner circumferences, and may be alternately laminated.

Since the back yoke 4 can secure a magnetic path with low magnetic resistance even if the axial length of the permanent magnet 10b of the sub-magnetic pole is shortened, the linear motor 4 when lengthening the axial length of the permanent magnet 10a of the main magnetic pole is used. The thrust of LM can be effectively improved. More specifically, when the back yoke 4 is provided on the outer periphery of the permanent magnets 10a and 10b, a magnetic path with low magnetic resistance can be secured, so that the increase in magnetic resistance due to the shortening of the axial length of the permanent magnet 10b of the secondary magnetic pole can be prevented. Suppressed. Therefore, if the axial length of the permanent magnet 10a of the main magnetic pole in the axial direction is longer than the length of the permanent magnet 10b of the secondary magnetic pole in the axial direction and the cylindrical back yoke 4 is provided around the outer circumference of the permanent magnets 10a and 10b, the linear motor LM It can greatly improve thrust. The thickness of the back yoke 4 may be set to a thickness suitable for suppressing an increase in the external magnetic resistance of the permanent magnet 10a of the main magnetic pole. The back yoke 4 can secure a magnetic path with low magnetic resistance even when the permanent magnets 10a and 10b are not arranged in a Halbach arrangement, so that the thrust of the linear motor LM can be improved.

In this embodiment, the back yoke 4 also functions as an outer shell of the electromagnetic shock absorber D1, and also serves as a strength member that protects the permanent magnets 10a and 10b and receives axial and lateral forces. If the back yoke 4 is provided, an increase in magnetic resistance can be suppressed, but the back yoke 4 can be omitted. It is preferable to provide a tube that functions as a protective member and a strength member for 10a and 10b.

In the electromagnetic shock absorber D1 constructed in this manner, the cylinder 1, the piston rod 2, the piston 3, the damping passage P, and the damping valve V constitute a hydraulic damper. M is accommodated in the hydraulic damper, and the stator S is attached to the outer circumference of the cylinder 1, so that the linear motor LM and the hydraulic damper are integrally and inseparably constructed.

The electromagnetic shock absorber D1 is configured as described above, and its operation will be described below. When the electromagnetic shock absorber D1 is extended by an external force, the piston 3 moves upward in FIG. 1 with respect to the cylinder 1, contracting the extension side chamber R1 and expanding the compression side chamber R2. Then, the hydraulic fluid moves from the contraction side chamber R1 to the expansion side chamber R2 via the damping passage P and the damping valve V. Since the hydraulic oil passes through the damping valve V, pressure loss occurs according to the flow rate of the passage, and the pressure in the expansion side chamber R1 rises, creating a pressure difference between the expansion side chamber R1 and the compression side chamber R2. The damper D1 functions as a damper to generate a damping force that impedes the extension actuation. When the electromagnetic shock absorber D1 is extended, the volume of the piston rod 2 withdrawing from the cylinder 1 is compensated for by the displacement of the free piston 7 and the expansion of the air chamber G. Moreover, since the electromagnetic shock absorber D1 is provided with the linear motor LM, the thrust generated by the linear motor LM can be used as a damping force for suppressing the extension operation. On the other hand, the thrust of the linear motor LM can positively extend the electromagnetic shock absorber D1 so that the electromagnetic shock absorber D1 can function as an actuator.

When the electromagnetic shock absorber D1 is contracted by an external force, the piston 3 moves downward in FIG. 1 with respect to the cylinder 1, contracting the pressure side chamber R2 and expanding the expansion side chamber R1. Then, the hydraulic fluid moves from the compression side chamber R2, which is contracted, to the expansion side chamber R1, which is expanded via the damping passage P and the damping valve V. Since the hydraulic fluid passes through the damping valve V, pressure loss occurs according to the flow rate of the passage, and the pressure in the compression side chamber R2 rises, creating a pressure difference between the compression side chamber R2 and the expansion side chamber R1. The damper D1 functions as a damper to generate a damping force that impedes the contraction actuation. When the electromagnetic shock absorber D1 is contracted, the volume of the piston rod 2 entering the cylinder 1 is compensated for by the displacement of the free piston 7 and the contraction of the air chamber G. Moreover, since the electromagnetic shock absorber D1 is provided with the linear motor LM, the thrust generated by the linear motor LM can be used as a damping force for suppressing the contraction operation. On the other hand, the electromagnetic shock absorber D1 can be made to function as an actuator by actively contracting the electromagnetic shock absorber D1 with the thrust of the linear motor LM.

The limit of thrust that can be generated while generating power when the linear motor LM is short-circuited and driven by an external force is shown by the dashed line in FIG. until the moving speed of the mover M with respect to the stator S, that is, the piston speed, which is the axial relative speed of the piston 3 with respect to the cylinder 1 of the electromagnetic shock absorber D1, reaches a high speed. becomes larger at higher speeds, but becomes smaller as the piston speed rises beyond high speed. FIG. 4 shows the characteristics of the force (total force of the thrust force of the linear motor LM and the damping force of the hydraulic damper) that can be generated by the electromagnetic shock absorber D1 as a whole. shows the characteristics when the electromagnetic shock absorber D1 exhibits an extension action and exerts a damping force that prevents extension, and in the second quadrant in the figure, the electromagnetic shock absorber D1 exhibits a contraction action and exerts a thrust force that promotes contraction. The third quadrant shows the characteristics in the state in which the electromagnetic shock absorber D1 exhibits contraction action and exerts a damping force that prevents contraction, and the fourth quadrant shows the characteristics in the state in which the electromagnetic shock absorber D1 exhibits extension action and extends. It shows the characteristics in the state of exerting a thrust that promotes

The characteristic of the pressure loss of the damping valve V of the present embodiment is set so that the characteristic is small when the flow rate is low and increases when the flow rate is high. The flow rate passing through the damping valve V increases in proportion to the piston speed, and the damping force generated by the electromagnetic shock absorber D1 is proportional to the pressure loss generated by the damping valve V. Therefore, in the electromagnetic shock absorber D1 in the present embodiment, the pressure loss of the damping valve V is tuned to compensate for the decrease in the upper limit of the thrust that can be generated by the linear motor LM, and the electromagnetic shock absorber D1 is damped. The damping force characteristics when the damping force is generated only by the valve V are set as indicated by the one-dot chain line in FIG. In this way, the total sum of the maximum thrust that can be generated by the linear motor LM and the damping force generated by the damping valve V is as indicated by the solid line in FIG. Therefore, the electromagnetic shock absorber D1 can generate necessary and sufficient damping force even if the piston speed becomes high. Further, when the electromagnetic shock absorber D1 is actively expanded and contracted by the thrust of the linear motor LM and used as an actuator, the damping force exerted by the damping valve V works as a resistance to prevent the expansion and contraction of the electromagnetic shock absorber D1. However, since the pressure loss PL generated with respect to the flow rate through which the damping valve V passes is set to be proportional to ^Qα , the piston speed when actively expanding and contracting the electromagnetic shock absorber D1 is such that the damping valve V can be made very small. Therefore, if the pressure loss PL generated with respect to the flow rate through which the damping valve V passes is set to be proportional to ^Qα , the electromagnetic shock absorber D1 can be actively expanded and contracted to function as an actuator. can suppress the reduction in thrust force due to the damping valve V, and when the electromagnetic shock absorber D1 functions as a damper, the damping force exerted by the damping valve V compensates for the thrust reduction of the linear motor LM with the damping force exerted by the damping valve V, thereby exerting a damping force suitable for the vehicle. can.

The pressure loss characteristics of the damping valve V are not limited to the characteristics described above, and other characteristics may be used as long as they can compensate for the drop in the thrust force of the linear motor LM when the piston speed becomes high. . Further, when the damping valve V is a damping force adjustment valve capable of adjusting the damping force, the damping force generated by the electromagnetic shock absorber D1 can be adjusted. By minimizing the resistance that the valve V gives to the flow of the hydraulic oil, it is possible to suppress the decrease in the thrust due to the damping valve V.

In the electromagnetic shock absorber D1 of this embodiment, the piston 3 is slidably inserted into the cylinder 1, the mover M is attached to the piston rod 2, and the stator S is attached to the outer circumference of the cylinder 1. Since the mover M is kept concentric with the stator S, the thrust force of the linear motor LM does not decrease. Further, in the present embodiment, a structure is adopted in which the magnetic field is mounted on the outer circumference of the cylinder 1 as the stator S. Even in the assembly process of inserting the piston rod 2 into the cylinder 1 fitted with the field system, contact between the mover M and the stator S is avoided, so that the permanent magnets 10a and 10b can be protected during the assembly process. . In this embodiment, the piston 3 is provided at the distal end of the piston rod 2 relative to the mover M, but may be provided at the proximal end side of the piston rod 2 relative to the mover M. Further, like the electromagnetic shock absorber D1-2 of the _second modification of the first embodiment shown in FIG. By disposing the mover M between the piston 3 and the slider 13, even if a lateral force acts on the electromagnetic shock absorber D1, the eccentricity of the mover M with respect to the stator S can be prevented. The device D1 can exert a stable damping force.

Thus, the electromagnetic shock absorber D1 of the present invention comprises a non-magnetic cylinder 1, a piston rod 2 movably inserted into the inner circumference of the cylinder 1, and a slidable piston rod 2 inserted into the cylinder 1. A piston 3 provided on the piston rod 2 and partitioning the inside of the cylinder 1 into an expansion side chamber R1 and a compression side chamber R2, a cylindrical mover M attached to the piston rod 2, and a mover provided on the outer periphery of the cylinder 1 A linear motor LM having a cylindrical stator S facing M, hydraulic oil (working fluid) filled in the growth side chamber R1 and the compression side chamber R2, and damping that communicates the growth side chamber R1 and the compression side chamber R2 It comprises a passage P and a damping valve V that resists the flow of hydraulic oil (hydraulic fluid) passing through the damping passage P.

The electromagnetic shock absorber D1 configured in this manner includes a hydraulic damper composed of a cylinder 1, a piston rod 2, a piston 3, a damping passage P, and a damping valve V, a mover M and a stator S A movable element M of the linear motor LM is housed in a hydraulic damper, and a stator S is mounted on the outer periphery of the cylinder 1. Therefore, according to the electromagnetic shock absorber D1 of the present invention, it is possible to reduce the size in the radial direction as compared with the conventional electromagnetic shock absorber, so that the mountability on the vehicle is improved and the weight can be reduced. Further, since the hydraulic damper is not covered with the linear motor, but rather the stator S and the cylinder 1 are integrated, the cooling performance of hydraulic oil (working liquid) of the hydraulic damper is improved while the vehicle is running. . Furthermore, in the electromagnetic shock absorber D1, since the sealing is required only around the piston rod 2 in the sliding portion, it is sufficient to install only the sealing member 5a, so that the friction during expansion and contraction of the electromagnetic shock absorber D1 can be reduced and the cost can be reduced. can also be reduced. Therefore, according to the electromagnetic shock absorber D1 of the present invention, it is possible to improve the mountability on the vehicle without impairing the cooling performance, reduce the weight and cost, and realize the smooth expansion and contraction operation.

In the above description, the stator S is used as the magnetic field and the mover M is used as the armature. A magnetic field may be formed by mounting a permanent magnet on the piston rod 2, and this may be used as the mover M.

Further, in the electromagnetic shock absorber D1 of the present embodiment, if Q is the flow rate passing through the damping passage P and α is an arbitrary value greater than 1, the pressure loss generated with respect to the flow rate passing through the damping valve V is , ^Qα , the reduction in thrust force due to the damping valve V can be suppressed when the electromagnetic buffer D1 functions as an actuator, and the linear motor LM when the electromagnetic buffer D1 functions as a damper. The decrease in the thrust of the vehicle can be compensated for by the damping force exerted by the damping valve V, and the damping force suitable for the vehicle can be exerted.

Further, in the electromagnetic shock absorber D1 of the present embodiment, the stator S has a plurality of annular permanent magnets 10a and 10b which are stacked and mounted on the outer circumference of the cylinder 1 along the axial direction, and the field magnet and a cylindrical back yoke 4 fitted to the outer periphery of the housing. In the electromagnetic shock absorber D1 configured in this manner, a magnetic path with low magnetic resistance can be secured by the back yoke 4, and the back yoke 4 can be used as an outer shell of the electromagnetic shock absorber D1. Therefore, according to the electromagnetic shock absorber D1 configured in this way, not only can the thrust of the linear motor LM be improved, but also the permanent magnets 10a and 10b can be protected, and the strength of the electromagnetic shock absorber D1 can be ensured.

Further, in the electromagnetic shock absorber D1 of the present embodiment, the free piston 7 is slidably inserted into the cylinder 1 and forms the air chamber G adjacent to the compression side chamber R2 in the cylinder 1. Even if the linear motor LM is integrally formed with the pressure damper, the volume of the piston rod 2 moving in and out of the cylinder 1 can be compensated.

The air chamber G1 can also be provided in the piston rod 2 like the electromagnetic shock absorber D13 of the _third modification of the first embodiment shown in FIG. In this case, the piston 3 is arranged on the upper side in FIG. there is In this case, the mover M is arranged in the compression-side chamber R2, and the upper and lower portions of the mover M in the compression-side chamber R2 in FIG. is ensured. The piston rod 2 is provided with a hollow portion 2b that opens in the axial direction from the tip, and a horizontal hole 2c that opens from the side between the mover M and the piston 3 and communicates with the hollow portion 2b. , and a cap 14 for closing the opening of the hollow portion 2b is attached to the tip. Further, a free piston 15 is slidably inserted in the hollow portion 2b of the piston rod 2, and the inside of the hollow portion 2b is communicated with the compression side chamber R2 through the horizontal hole 2c by the free piston 15. It is divided into a chamber L and an air chamber G1 filled with gas. In the electromagnetic shock absorber D13 of the _third modification of the first embodiment configured in this way, the air chamber G1 is provided in the piston rod 2, so an air chamber is provided below the compression side chamber R2. Therefore, a longer stroke length can be ensured compared to the electromagnetic shock absorber D1 in which the air chamber G is provided below the compression side chamber R2. Therefore, in the electromagnetic shock absorber D1-3 of the _third modification of the first embodiment, a long stroke length can be ensured. can increase the thrust of

Furthermore, in the electromagnetic shock absorber D1 of the present embodiment, the damping passage P communicates the expansion side chamber R1 and the compression side chamber R2 through the piston rod 2, and the damping valve V is inside the piston rod 2 and inside the mover M. provided on the periphery. In the electromagnetic shock absorber D1 configured in this way, even if a damping valve V that requires a space in the radial direction is employed, the damping valve V is arranged on the inner peripheral side of the mover M, so that the stroke length is easier to secure.

<Second embodiment>
Next, the electromagnetic shock absorber D2 of the second embodiment will be explained. As shown in FIG. 7, the electromagnetic shock absorber D2 in the second embodiment is provided with an outer tube 16 on the outer circumference of the stator S, and between the stator S and the outer tube 16, the piston rod 2 is inserted into the cylinder 1. A reservoir R is provided to compensate for the volume entering and exiting. That is, the electromagnetic shock absorber D1 of the first embodiment provided the air chamber G in the cylinder 1 to compensate for the volume of the piston rod 2, but in the electromagnetic shock absorber D2 of the second embodiment, A reservoir R is provided in place of the air chamber G.

A specific configuration of the electromagnetic shock absorber D2 of the second embodiment will be described. The electromagnetic shock absorber D2 of the second embodiment, as shown in FIG. A piston 3 which is movably inserted and provided on the piston rod 2 to divide the inside of the cylinder 1 into an expansion side chamber R1 and a compression side chamber R2; A linear motor LM having a stator S facing the mover M, an outer tube 16 covering the outer periphery of the stator S and forming a reservoir R between the stator S, an expansion side chamber R1 and a compression side chamber. Hydraulic oil as a hydraulic fluid filled in R2, a damping passage P that communicates the expansion side chamber R1 and the compression side chamber R2, a damping valve V that provides resistance to the flow of hydraulic oil passing through the damping passage P, and a compression side A discharge passage EP that communicates the chamber R2 and the reservoir R, a base valve BV that provides resistance to the flow of hydraulic fluid passing through the discharge passage EP, and a suction that allows only the flow of hydraulic fluid from the reservoir R toward the compression side chamber R2. passage SP.

That is, the electromagnetic shock absorber D2 of the second embodiment eliminates the free piston 7 from the configuration of the electromagnetic shock absorber D1 of the first embodiment, and has a reservoir R, an exhaust passage EP, a base valve BV and a suction passage. It is set as the structure which provided SP.

In the following, parts of the electromagnetic damper D2 of the second embodiment that differ from the electromagnetic damper D1 of the first embodiment will be described in detail. In the electromagnetic shock absorber D2 of the second embodiment, the lower end of the cylinder 1 in FIG. R2 is filled with working oil as working fluid.

A rod guide 5 is fitted to the upper end of the cylinder 1 in FIG. 7 and fixed to the upper end of the outer tube 16 . Also, the lower end of the outer tube 16 in FIG. 7 is closed by attaching a cap 18 having a bracket 18a. The cylinder 1 and the stator S are fixed in the outer tube 16 by being sandwiched between rod guides 5 and caps 18 attached to the upper and lower ends of the outer tube 16 .

The reservoir R is formed by an annular gap between the back yoke 4 and the outer tube 16 of the stator S, and is filled with hydraulic oil as hydraulic fluid as well as gas such as inert gas. In the electromagnetic shock absorber D2 of the second embodiment, the stator S is accommodated in the outer tube 16, and the outer tube 16 can be used as a cover body for protecting the permanent magnets 10a and 10b. Yoke 4 may be omitted.

A valve case 17 attached to the lower end of the cylinder 1 in FIG. 7 is provided with an exhaust passage EP, a base valve BV and a suction passage SP. The discharge passage EP communicates the pressure-side chamber R2 and the reservoir R, and the base valve BV is provided in the discharge passage EP and is an orifice in this embodiment. Similarly to the damping valve V, the base valve BV has Q representing the flow rate of the hydraulic oil passing through it, PL representing the pressure loss generated with respect to the flow rate through which the base valve BV passes, and α representing an arbitrary value greater than 1, Assuming that an arbitrary coefficient is β, the pressure flow characteristic of the base valve BV is set to be P= ^β ×Qα. That is, the pressure loss PL generated with respect to the flow rate through which the base valve BV passes is set to be proportional to ^Qα . In addition to the orifice, the base valve BV may be a choke or leaf valve, or may be a damping force adjustment valve capable of adjusting the damping force.

The suction passage SP includes a passage 20 that communicates between the reservoir R and the pressure-side chamber R2, and a check valve 21 that is provided in the passage 20 and allows only the flow of hydraulic oil from the reservoir R toward the pressure-side chamber R2. Therefore, in the suction passage SP, when the pressure in the pressure-side chamber R2 is higher than the pressure in the reservoir R, the check valve 21 closes the passage 20 to prevent the hydraulic fluid from passing through. When the pressure of the reservoir R falls below the pressure, the check valve 21 opens the passage 20 to allow the hydraulic fluid to flow from the reservoir R to the compression side chamber R2. In the case of this embodiment, the base valve BV is an orifice. Therefore, when the check valve 21 is a leaf valve, the passage 20 of the suction passage SP is also used as the discharge passage EP so that the check valve 21 may be provided with an orifice which always communicates with the passage 20, and this orifice may be the base valve BV. However, if the base valve BV is a valve having a check valve function such as a leaf valve, the passage 20 of the suction passage SP cannot be used as the discharge passage EP.

Further, in the electromagnetic shock absorber D2 of the present embodiment, in addition to the damping passage P in which the damping valve V is provided, the check valve 23 is provided to allow only the flow of hydraulic oil from the compression side chamber R2 to the expansion side chamber R1. 22 are provided.

The electromagnetic shock absorber D2 of the second embodiment is constructed as described above, and its operation will be described below. When the electromagnetic shock absorber D2 is extended by an external force, the piston 3 moves upward in FIG. 7 with respect to the cylinder 1, contracting the extension side chamber R1 and expanding the compression side chamber R2. Then, the hydraulic fluid moves from the contraction side chamber R1 to the expansion side chamber R2 via the damping passage P and the damping valve V. Since the hydraulic oil passes through the damping valve V, pressure loss occurs according to the flow rate of the passage, and the pressure in the expansion side chamber R1 rises, creating a pressure difference between the expansion side chamber R1 and the compression side chamber R2. The damper D2 functions as a damper to generate a damping force that opposes the extension actuation. When the electromagnetic shock absorber D2 is extended, the check valve 21 in the suction passage SP is opened to compensate for the amount of hydraulic oil corresponding to the volume of the piston rod 2 withdrawing from the cylinder 1, which is supplied from the reservoir R into the cylinder 1. . Moreover, since the electromagnetic shock absorber D2 is provided with the linear motor LM, the thrust generated by the linear motor LM can be used as a damping force for suppressing the extension operation. On the other hand, the thrust of the linear motor LM can positively extend the electromagnetic shock absorber D2 so that the electromagnetic shock absorber D2 can function as an actuator.

When the electromagnetic shock absorber D2 is contracted by an external force, the piston 3 moves downward in FIG. 7 with respect to the cylinder 1, contracting the pressure side chamber R2 and expanding the expansion side chamber R1. Then, since the check valve 23 is opened and the passage 22 is opened, hydraulic fluid moves from the contraction side chamber R2 through the passage 22 to the expansion side chamber R1. When the electromagnetic shock absorber D2 is contracted, the piston rod 2 enters the cylinder 1, so that the volume of hydraulic oil that the piston rod 2 enters into the cylinder 1 becomes excessive. This excess hydraulic oil is discharged to the reservoir R via the discharge passage EP and the base valve BV. When the electromagnetic shock absorber D2 is contracted, the expansion side chamber R1 and the compression side chamber R2 are communicated with each other through the passage 22, so that the pressures in the expansion side chamber R1 and the compression side chamber R2 are almost equal, but hydraulic fluid does not pass through the base valve BV. Therefore, the pressure in the entire cylinder 1 increases. Since the piston rod 2 is inserted only through the expansion chamber R1, the pressure receiving area of the piston 3 is larger in the compression chamber R2 than in the expansion chamber R1. The damper D2 functions as a damper to generate a damping force that impedes the contraction actuation. Hydraulic oil pushed away by the piston rod 2 entering the cylinder 1 is discharged to the reservoir R as described above, so that the volume of the piston rod 2 entering the cylinder 1 is compensated. Moreover, since the electromagnetic shock absorber D2 is provided with the linear motor LM, the thrust generated by the linear motor LM can be used as a damping force for suppressing the contraction operation. On the other hand, the electromagnetic shock absorber D2 can be made to function as an actuator by actively contracting the electromagnetic shock absorber D2 with the thrust of the linear motor LM.

The characteristics of the pressure loss of the damping valve V and the base valve BV in the electromagnetic shock absorber D2 of the present embodiment are set so that the characteristics are small when the flow rate is low and increase when the flow rate is high. The damping valve V generates damping force when the electromagnetic damper D2 is extended, and the base valve BV generates damping force when the electromagnetic damper D2 is retracted. Therefore, in the electromagnetic shock absorber D2 according to the present embodiment, if the pressure loss of the damping valve V and the base valve BV is tuned to compensate for the decrease in the upper limit of the thrust that can be generated by the linear motor LM, the electromagnetic Like the damper D1, the electromagnetic damper D2 can generate a necessary and sufficient damping force even if the piston speed becomes high. In this embodiment, the damping valve V is provided with a passage 22 so that it functions as a damping force generation source only when the electromagnetic shock absorber D2 is extended. The damping force during extension operation and contraction operation of the shock absorber D2 can be tuned independently. The damping valve V may function as a damping force generation source both when the electromagnetic shock absorber D2 expands and contracts, and the base valve BV functions as a damping force generation source only when the electromagnetic shock absorber D2 contracts. By tuning the valve V and the base valve BV, it is possible to tune the damping force during the extension operation and contraction operation of the electromagnetic shock absorber D2.

The pressure loss characteristics of the damping valve V and the base valve BV are not limited to the characteristics described above. I wish I could make up for it. Further, when the damping valve V and the base valve BV are damping force adjusting valves capable of adjusting the damping force, the damping force generated by the electromagnetic shock absorber D2 can be adjusted, and the electromagnetic shock absorber D2 functions as an actuator. In this case, the reduction in thrust due to the damping valve V can be suppressed by minimizing the resistance exerted by the damping valve V and the base valve BV on the flow of hydraulic fluid.

Thus, the electromagnetic shock absorber D2 of the second embodiment includes a nonmagnetic cylinder 1, a piston rod 2 movably inserted into the inner circumference of the cylinder 1, and a piston rod 2 slidably inside the cylinder 1. A piston 3 which is inserted and provided on the piston rod 2 and divides the inside of the cylinder 1 into an extension side chamber R1 and a compression side chamber R2, a mover M attached to the piston rod 2, and a movable member M provided on the outer periphery of the cylinder 1 A linear motor LM having a stator S facing the element M, an outer tube 16 that covers the outer periphery of the stator S and forms a reservoir R between the stator S, and a growth side chamber R1 and a compression side chamber R2. Hydraulic oil as a hydraulic fluid to be filled, a damping passage P that communicates the expansion side chamber R1 and the compression side chamber R2, a damping valve V that provides resistance to the flow of the hydraulic oil passing through the damping passage P, and a compression side chamber R2. A discharge passage EP that communicates with the reservoir R, a base valve BV that provides resistance to the flow of hydraulic fluid passing through the discharge passage EP, and a suction passage SP that allows only the flow of hydraulic fluid from the reservoir R toward the compression side chamber R2. is configured with

The electromagnetic shock absorber D2 configured in this manner includes a hydraulic damper composed of a cylinder 1, a piston rod 2, a piston 3, a damping passage P, and a damping valve V, a movable element M and a stator S A movable element M of the linear motor LM is housed in a hydraulic damper, and a stator S is mounted on the outer periphery of the cylinder 1. Therefore, according to the electromagnetic shock absorber D2, compared with the conventional electromagnetic shock absorber, the size in the radial direction can be reduced, so that the mountability to the vehicle can be improved and the weight can be reduced. Further, since the hydraulic damper is not covered with the linear motor, but rather the stator S and the cylinder 1 are integrated, the cooling performance of hydraulic oil (working fluid) of the hydraulic damper is improved while the vehicle is running. . Furthermore, in the electromagnetic shock absorber D2, since the sliding part requires a seal only around the piston rod 2, it is sufficient to install only the seal member 5a. can also be reduced. Therefore, according to the electromagnetic shock absorber D2 of the present invention, it is possible to improve the mountability on the vehicle without impairing the cooling performance, reduce the weight and cost, and realize the smooth expansion and contraction operation.

Furthermore, since the electromagnetic shock absorber D2 of the second embodiment does not need to provide the air chamber G in the cylinder 1, compared to the electromagnetic shock absorber D1 in which the air chamber G is provided below the compression side chamber R2, A long stroke length can be secured. Therefore, in the electromagnetic shock absorber D2 of the second embodiment, a long stroke length can be ensured, and when the mover M is used as an armature, the overall length of the mover M can be increased and the thrust of the linear motor LM can be increased. Further, even if the linear motor LM is integrally formed with the hydraulic damper, it is possible to compensate for the volume of the piston rod 2 moving in and out of the cylinder 1 .

Instead of forming the reservoir R by providing the outer tube 16 on the outer periphery of the stator S like the electromagnetic shock absorber D21 in the _first modification of the second embodiment shown in FIG. A tank T having a reservoir R therein may be provided on the side of the cylinder 1 . The tank T is connected to the cap 6 provided at the lower end of the cylinder 1 via a connecting portion 25, and is arranged parallel to the cylinder 1 in this embodiment. The inside of the tank T is hollow, and a free piston 26 is slidably inserted therein. The inside of the tank T is divided into a liquid chamber L1 and an air chamber G2 by the free piston 26, and functions as a reservoir R. . Further, in this case, as shown in FIG. 8, a valve case 17 is provided inside the tank T, and a base valve BV is provided inside the tank T. The connecting portion 25 has a cylindrical shape and communicates with the pressure side chamber R2 and the inside of the tank T. The pressure side chamber R2 communicates with the liquid chamber L1 in the reservoir R via the discharge passage EP and the suction passage SP. It is

Instead of the structure in which the outer tube 16 is provided and the reservoir R is formed between the stator S and the outer tube 16, a structure in which the tank T is provided and the reservoir R is provided in the tank T may be used. There is no need to provide an air chamber G in Therefore, the electromagnetic shock absorber D2-1 of the _first modification of the second embodiment can secure a longer stroke length than the electromagnetic shock absorber D1 in which the air chamber G is provided below the compression side chamber R2, and the mover M is used as the armature, the total length of the mover M can be increased, so that the thrust of the linear motor LM can be increased. Further, even if the linear motor LM is integrally formed with the hydraulic damper, it is possible to compensate for the volume of the piston rod 2 moving in and out of the cylinder 1 .

Further, in the electromagnetic shock absorber D21 according to the _first modification of the second embodiment, the base valve BV is provided inside the tank T, so the need to mount the valve case 17 on the cylinder 1 is eliminated. _The stroke length of the electromagnetic shock absorber D2-1 can be made longer. Therefore, according to the electromagnetic shock absorber D21 in the _first modified example of the second embodiment, the thrust force of the linear motor LM can be further increased. Note that the base valve BV may be provided inside the connecting portion 25 .

Although preferred embodiments of the invention have been described in detail above, modifications, variations, and changes are possible without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 1... Cylinder, 2... Piston rod, 2a... Hole, 2b... Hollow part, 3... Piston, 4... Back yoke (cover body), 7, 15, 26... Free piston 10a, 10b Permanent magnet 16 Outer tube 25 Connecting portion BV Base valve EP Exhaust passage D1, D1 ₁ , D1 ₂ , D1 ₃ , D2, D2 ₁ ...Electromagnetic buffer, G, G1, G2...Air chamber, L, L1...Liquid chamber, LM...Linear motor, M...Motor, P... Attenuation passage, R: reservoir, R1: expansion side chamber, R2: compression side chamber, S: stator, SP: suction passage, T: tank, V: damping valve

Claims (9)

a non-magnetic cylinder;
a piston rod movably inserted into the inner circumference of the cylinder;
a piston slidably inserted into the cylinder and provided on the piston rod to divide the inside of the cylinder into an expansion-side chamber and a compression-side chamber;
a linear motor having a cylindrical mover mounted on the piston rod and housed in the cylinder, and a cylindrical stator provided on the outer circumference of the cylinder and facing the mover;
a working liquid filled in the expansion-side chamber and the compression-side chamber;
a damping passage that communicates the expansion side chamber and the compression side chamber;
and a damping valve that resists the flow of hydraulic fluid passing through the damping passage. Let Q be the flow rate passing through the damping passage, and α be an arbitrary value greater than 1. The pressure loss generated with respect to the flow rate passing through the damping valve is set to be proportional to Q ^α . The electromagnetic buffer according to claim 1, characterized by: The stator is
a field magnet having a plurality of annular permanent magnets stacked and mounted along the axial direction on the outer periphery of the cylinder;
The electromagnetic shock absorber according to claim 1 or 2, further comprising a cylindrical cover body provided on the outer circumference of the field system. The electromagnetic according to any one of claims 1 to 3, further comprising a free piston that is slidably inserted into the cylinder and forms an air chamber within the cylinder adjacent to the compression side chamber. buffer. The piston rod has a hollow portion that communicates with the pressure-side chamber,
4. The free piston according to any one of claims 1 to 3, further comprising a free piston that is slidably inserted into the hollow portion and divides the hollow portion into a liquid chamber communicating with the pressure-side chamber and an air chamber. The electromagnetic buffer described in the paragraph. an outer tube that covers the outer periphery of the stator and forms a reservoir between itself and the stator;
a discharge passage communicating between the pressure-side chamber and the reservoir;
a base valve that resists the flow of hydraulic fluid through the discharge passage;
The electromagnetic shock absorber according to any one of claims 1 to 3, further comprising a suction passage that allows only the flow of the working fluid from the reservoir to the pressure-side chamber. a tank provided on the side of the cylinder and having a reservoir therein;
a discharge passage communicating between the pressure-side chamber and the reservoir;
a base valve that resists the flow of working fluid through the exhaust passage;
The electromagnetic shock absorber according to any one of claims 1 to 3, further comprising a suction passage that allows only the flow of the working fluid from the reservoir to the pressure-side chamber. The damping passage communicates the expansion side chamber and the compression side chamber through the piston rod,
The electromagnetic shock absorber according to any one of claims 1 to 7, wherein the damping valve is provided inside the piston rod and on the inner peripheral side of the mover. A connecting portion that connects the cylinder and the tank,
9. The electromagnetic shock absorber according to claim 7 or claim 8 depending on claim 7, wherein the base valve is provided in the connecting portion or the tank.

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