JP7049281B2 - Electromagnetic shock absorber - Google Patents

Description

The present invention relates to an electromagnetic shock absorber.

The electromagnetic shock absorber is provided with, for example, a linear motor composed of an armature and a field, and the thrust generated by the linear motor is used as a damping force for suppressing vibration of the vehicle body of an automobile, or a control for controlling the posture of the vehicle body. Use it as a force.

In such an electromagnetic shock absorber, the thrust of the linear motor is used as a damping force or a control force, but in order to generate the thrust in the linear motor, it is necessary to energize the winding provided in the armature, which is large. In order to generate the damping force, the amount of current supplied to the winding is also large.

When the amount of current applied to the winding becomes large, the winding heats up and becomes high temperature, and when the temperature inside the electromagnetic shock absorber becomes high, the magnetic field of the permanent magnet on the field side is weakened by thermal demagnetization, and the electromagnetic shock absorber There is a risk that the damping force that can be generated will decrease.

Therefore, in the conventional electromagnetic shock absorber, a field magnet mounted on the outer circumference of the cylindrical fixed yoke, a tubular armature provided on the inner circumference of the tubular movable yoke provided on the outer circumference of the field magnet, and a tubular armature are used. It is equipped with a cylindrical case that is connected to the fixed yoke and slides into the outer circumference of the movable yoke, and passes through the inner and outer circumferences of the armature winding when the movable yoke moves relative to the fixed yoke. And let the gas pass through the passage to dissipate heat from the armature (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2003-324934

In a conventional electromagnetic shock absorber, when the gas in the space closed by the movable yoke and the case flows during relative movement of the movable yoke with respect to the fixed yoke, the gas passes through the inner and outer peripheral passages of the armature winding. However, since the passage itself causes a pressure loss, heat is generated in the passage, so that the cooling effect is diminished. If a sufficient cooling effect cannot be obtained, the amount of current in the winding must be reduced, and in order to obtain a large thrust even with a small current, it is inevitable to increase the size of the electromagnetic shock absorber.

Therefore, an object of the present invention is to provide an electromagnetic shock absorber that can avoid an increase in size and reduce weight and cost while obtaining a large thrust.

In order to achieve the above object, the electromagnetic shock absorber of the present invention includes a non-magnetic cylinder, a piston rod that is movably inserted into the inner circumference of the cylinder, and a piston that is slidably inserted into the cylinder and a piston. An extension piston provided on the rod to partition the extension chamber in the cylinder, and a piston rod provided on the piston rod with a slidable insertion into the cylinder and an axial distance from the extension piston in the cylinder. A compression side piston that divides the compression side chamber, a tubular armor mounted between the extension side piston and the compression side piston of the piston rod, and a tubular field magnet provided on the outer circumference of the cylinder and facing the armature. A linear motor having a The extension side limiting part, the extension side rectifying part that communicates the extension side chamber to the cooling passage and allows only the flow of gas from the cooling passage to the extension side chamber, and the compression side chamber communicates with the cooling passage and the cooling passage from the compression side chamber. It is provided with a compression side limiting unit that resists the flow of gas toward the pressure side, and a compression side rectifying unit that communicates the compression side chamber to the cooling passage and allows only the flow of gas from the cooling passage to the compression side chamber.

In the electromagnetic shock absorber configured in this way, when the gas moves back and forth between the extension side chamber and the compression side chamber through the cooling passage during expansion and contraction operation, the pressure in the cooling passage is always on the low pressure side of the extension side chamber and the compression side chamber. Since the gas equal to the pressure and invades into the cooling passage from the chamber on the high pressure side of the extension side chamber and the compression side chamber expands and the temperature drops, the armature facing the cooling passage can be effectively cooled.

Further, the electromagnetic shock absorber has a cylindrical core in which the armature is cylindrical and has a plurality of annular slots on the outer circumference, and a winding wire mounted in the slots, and the cooling passage is the outer circumference of the piston rod. It may be formed by an annular gap between the inner circumference of the core. According to the electromagnetic shock absorber configured in this way, the entire inner circumference of the core can be exposed to the gas whose temperature has dropped, so that the armature can be cooled evenly and evenly in the circumferential direction, and the structure of the core is simplified and the cooling passage is simplified. No processing is required to provide the above.

Further, the electromagnetic shock absorber may have a cylindrical heat sink on the inner circumference of the core, and when configured in this way, the heat sink can be exposed to the gas passing through the cooling passage, and the heat sink can be efficiently wound. And can cool the core.

Further, the electromagnetic shock absorber may be provided with a vent hole that opens from the outer periphery to the cooling passage in the core, and if it is configured in this way, the armature can be cooled more effectively, so that a large thrust is obtained. It becomes easier and the electromagnetic shock absorber can be further miniaturized.

Further, the electromagnetic shock absorber is an annular check valve having a notch provided in the extension side piston by the extension side limiting part and the extension side rectifying part, and has a notch provided in the compression side piston by the compression side limiting part and the compression side rectifying part. It may be an annular check valve provided. According to the electromagnetic shock absorber configured in this way, the extension side limiting part and the extension side rectifying part, and the compression side limiting part and the compression side rectifying part are each composed of an annular check valve having a short axial length dimension. It becomes easy to secure the stroke length of the electromagnetic shock absorber.

According to the electromagnetic shock absorber of the present invention, it is possible to avoid an increase in size and reduce the weight and cost while obtaining a large thrust.

It is a vertical sectional view of the electromagnetic shock absorber of one Embodiment.

Hereinafter, the present invention will be described based on the embodiments shown in the figure. As shown in FIG. 1, the electromagnetic shock absorber D in one embodiment has a non-magnetic cylinder 1, a piston rod 2 movably inserted into the inner circumference of the cylinder 1, and a slidable inside the cylinder 1. The extension-side piston 3 is inserted into the piston rod 2 and is provided on the piston rod 2 to partition the extension-side chamber R1 in the cylinder 1, and is slidably inserted into the cylinder 1 and axially with respect to the extension-side piston 3. A tubular armor mounted between the compression side piston 4 provided on the piston rod 2 at intervals and partitioning the compression side chamber R2 in the cylinder 1 and the extension side piston 3 and the compression side piston 4 of the piston rod 2. A linear motor LM having an E and a tubular field F facing the armature E provided on the outer periphery of the cylinder 1, a gas filled in the extension side chamber R1 and the compression side chamber R2, and a surface on the armature E. It is provided with a cooling passage CP, an extension side limiting unit ER, an extension side rectifying unit EC, a compression side limiting unit CR, and a compression side rectifying unit CC.

Hereinafter, each part of the electromagnetic shock absorber D will be described in detail. The cylinder 1 is tubular and is made of a non-magnetic material, and a tubular back yoke 9 made of a soft magnetic material that forms an annular gap with the cylinder 1 is provided on the outer periphery of the cylinder 1. Has been done. An annular rod guide 5 that fits into the middle upper end of FIG. 1 of the cylinder 1 is attached to the upper middle end of FIG. 1 of the back yoke 9, and the lower middle end of FIG. 1 of the cylinder 1 is attached to the lower middle end of FIG. A cap 6 that fits into the cylinder 6 is attached. The cap 6 is provided with a bracket 6a that can be attached to the vehicle.

The piston rod 2 is inserted through the inner circumference of the rod guide 5 and movably inserted into the cylinder 1, and the extension side piston 3, the armature E, and the compression side piston 4 are mounted on the outer periphery thereof. Although not shown, a bracket that can be mounted on a vehicle is provided at the upper end of FIG. 1, which is the base end of the piston rod 2. Further, a sealing member 5a is provided on the inner circumference of the rod guide 5, and the inside of the cylinder 1 is airtightly sealed.

The extension side piston 3 and the compression side piston 4 are attached to the outer periphery of the piston rod 2 at an axial interval, and the armature E is the outer circumference of the piston rod 2 and includes the extension side piston 3 and the compression side piston 4. It is attached in a state of being in contact with both of them.

The extension-side piston 3 is annular and is attached to the piston rod 2 and slidably inserted into the cylinder 1 as described above, and the extension-side chamber R1 is partitioned upward in FIG. 1 in the cylinder 1. ing. Further, in the present embodiment, the compression side piston 4 has an annular shape, is attached to the piston rod 2 as described above, and is slidably inserted into the cylinder 1, and is slidably inserted into the cylinder 1 in the lower part of FIG. The compression side chamber R2 is partitioned. The extension side chamber R1 and the compression side chamber R2 are filled with gas. As the gas, a gas used as a refrigerant such as hydrochlorofluorocarbon, hydrofluorocarbon, perfluorocarbon and the like may be used, but other gases may be used.

The extension-side piston 3 has a piston ring 3a that is in sliding contact with the cylinder 1 on the outer periphery, an annular convex portion 3b provided at the armature side end, and an annular convex portion 3b that opens from the extension-side chamber side end at the upper end in FIG. 1 is provided with a plurality of through holes 3c leading to the armature side end, which is the lower end in FIG. 1, and an annular valve seat 3d provided at the extension side chamber side end and surrounding the outlet end of the through hole 3c. At the end of the extension side piston 3 on the extension side chamber side, a check valve 7 made of an annular plate that takes off and sits on the annular valve seat 3d and opens and closes the outlet end of the through hole 3c is provided. The check valve 7 has a notch 7a that functions as an orifice on the outer circumference, and the inner peripheral side is a fixed end to allow bending of the outer peripheral side. When seated on the annular valve seat 3d, the through hole 3c is closed. The extension side chamber R1 and the through hole 3c are communicated with each other only by the notch 7a, and when the valve seat 3d is bent away from the annular valve seat 3d, the outlet end of the through hole 3c is opened. Therefore, the check valve 7 makes the notch 7a effective for the gas flow from the extension side chamber R1 to the through hole 3c side to give resistance to the gas flow, and the check valve 7 makes the gas flow from the through hole 3c toward the extension side chamber R1. Allow this with little resistance to the flow. Therefore, in the present embodiment, the extension side limiting unit ER is configured by the notch 7a of the check valve 7, and the extension side rectifying unit EC is configured by the check valve 7. The configuration of the extension side limiting unit ER and the extension side rectifying unit EC is not limited to the above, but the check valve 7 is made of one annular plate and has a short axial dimension, and the extension side limiting unit ER and the extension side are extended. If the rectifying unit EC is integrated, there is an advantage that it becomes easy to secure the stroke length of the electromagnetic shock absorber D.

The compression side piston 4 has a piston ring 4a that is in sliding contact with the cylinder 1 on the outer periphery, an annular convex portion 4b provided at the armature side end, and an annular convex portion 4b that is opened from the compression side chamber side end at the lower end in FIG. It is provided with a plurality of through holes 4c leading to the armature side end, which is the upper end in FIG. 1, and an annular valve seat 4d provided at the compression side chamber side end and surrounding the outlet end of the through hole 4c. A check valve 8 made of an annular plate that takes off and sits on the annular valve seat 4d to open and close the outlet end of the through hole 4c is provided at the compression side chamber side end of the compression side piston 4. The check valve 8 has a notch 8a that functions as an orifice on the outer circumference, and the inner peripheral side is a fixed end to allow bending of the outer peripheral side. When seated on the annular valve seat 4d, the through hole 4c is closed. The compression side chamber R2 and the through hole 4c are communicated with each other only by the notch 8a, and when the valve seat 4d is bent and separated from the annular valve seat 4d, the outlet end of the through hole 4c is opened. Therefore, the check valve 8 makes the notch 8a effective for the gas flow from the compression side chamber R2 toward the through hole 4c side to give resistance to the gas flow, and the check valve 8 makes the gas flow from the through hole 4c toward the compression side chamber R2. Allow this with little resistance to the flow. Therefore, in the present embodiment, the compression side limiting unit CR is configured by the notch 8a of the check valve 8, and the compression side rectifying unit CC is configured by the check valve 8. The configuration of the compression side limiting unit CR and the compression side rectifying unit CC is not limited to the above, but the compression side limiting unit CR and the compression side rectifying unit CC are attached to the check valve 8 which is made of one annular plate and has a short axial dimension. If aggregated, there is an advantage that it becomes easy to secure the stroke length of the electromagnetic shock absorber D.

The armature E is a winding mounted in a tubular iron core 11 arranged on the outer periphery of the piston rod 2 and a slot 11a formed of an annular groove provided on the outer periphery of the core 11 at a predetermined pitch in the axial direction. It is configured to include a wire 12. The winding 12 mounted in the slot 11a is a U-phase, V-phase, and W-phase three-phase winding. An annular gap is provided between the outer circumference of the core 11 and the inner circumference of the cylinder 1 so that the core 11 and the cylinder 1 do not directly interfere with each other.

Further, the core 11 is provided with a tubular heat radiating plate 11b formed of a metal having a high thermal conductivity such as copper on the inner circumference thereof. The inner diameter of the heat sink 11b, which is the minimum inner diameter of the core 11, is larger than the outer diameter of the piston rod 2, and an annular gap is formed between the inner circumference of the core 11 and the outer circumference of the piston rod 2. A cooling passage CP is provided in this annular gap. The core 11 is fitted to the annular convex portion 3b of the extension side piston 3 and the annular convex portion 4b of the compression side piston 4, and is positioned radially while being sandwiched between the extension side piston 3 and the compression side piston 4 and the piston rod 2. Is fixed to. Since the through holes 3c and the through holes 4c are open to the armature side ends of the annular convex portions 3b and 4b, they communicate with the cooling passage CP, respectively, and the through holes 3c and 4c and the cooling passage CP provide the extension side chamber R1. It communicates with the compression side chamber R2.

Further, the core 11 is provided with a plurality of ventilation holes 11c that open from the outer periphery to the inner circumference of the heat radiating plate 11b, and the cooling passage CP and the gap between the cylinder 1 and the core 11 communicate with each other by the ventilation holes 11c. Has been done.

Subsequently, a plurality of annular permanent magnets 10a and 10b are laminated and mounted on the outer periphery of the cylinder 1, and these permanent magnets 10a and 10b are placed in the annular gap between the cylinder 1 and the back yoke 9. It is contained. In the present embodiment, the permanent magnets 10a and 10b and the back yoke 9 form a field F in which magnetic fields of S pole and N pole are alternately applied to the inner peripheral side of the cylinder 1. Since the cylinder 1 is made of a non-magnetic material, the magnetic field generated by the field F can pass through the cylinder 1 and act on the cylinder 1.

Further, in the present embodiment, the permanent magnets 10a of the main magnetic pole and the permanent magnets 10b of the sub magnetic pole are laminated so that the S pole and the N pole appear alternately on the inner peripheral side of the cylinder 1 in the Halbach array. ing. In FIG. 1, the triangular marks on the permanent magnet 10a of the main magnetic pole and the permanent magnet 10b of the secondary magnetic pole indicate the magnetizing direction, and the magnetizing direction of the permanent magnet 10a of the main magnetic pole is the radial direction. The magnetizing direction 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 axial length of the permanent magnet 10b of the secondary magnetic pole, and the magnetism between the core 11 and the permanent magnet 10a of the main magnetic pole in the armature E. 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 may not be arranged in a Halbach array because a magnetic field may be applied to the inner peripheral side of the cylinder 1 so that S poles and N poles appear alternately in the axial direction. In that case, the permanent magnets 10a and 10b may have the same axial length and have different magnetic poles on the inner circumferences of the permanent magnets 10a and 10b, and may be stacked alternately.

Since the back yoke 9 can secure a magnetic path having low magnetic resistance even if the axial length of the permanent magnet 10b of the secondary magnetic pole is shortened, a linear motor for increasing the axial length of the permanent magnet 10a of the main magnetic pole. The thrust of the LM can be effectively improved. More specifically, if the back yoke 9 is provided on the outer periphery of the permanent magnets 10a and 10b, a magnetic path having a low magnetic resistance can be secured, so that the magnetic resistance increases due to the shortening of the axial length of the permanent magnet 10b of the secondary magnetic pole. It is suppressed. Therefore, if the axial length of the permanent magnet 10a of the main magnetic pole is made longer than the axial length of the permanent magnet 10b of the secondary magnetic pole and the tubular back yoke 9 is provided on the outer periphery of the permanent magnets 10a and 10b, the linear motor LM The thrust can be greatly improved. The wall thickness of the back yoke 9 may be set to a wall thickness suitable for suppressing an increase in the external magnetic resistance of the permanent magnet 10a of the main magnetic pole. Since the back yoke 9 can secure a magnetic path having a low magnetic resistance even when the permanent magnets 10a and 10b are not arranged in a Halbach array, the thrust of the linear motor LM can be improved.

In the present embodiment, the back yoke 9 also functions as an outer shell of the electromagnetic shock absorber D, and also serves as a protection member for the permanent magnets 10a and 10b and as a strength member that receives axial force and lateral force. If the back yoke 9 is provided, an increase in magnetic resistance can be suppressed, but the back yoke 9 can be omitted. If the back yoke 9 is omitted, the permanent magnets do not function as back yokes on the outer circumferences of the permanent magnets 10a and 10b, but are permanent magnets. It is preferable to provide a cylinder that protects 10a and 10b and functions as a strength member.

The electromagnetic shock absorber D is configured as described above, and its operation will be described below. When the electromagnetic shock absorber D is extended, the piston rod 2 moves upward in FIG. 1 with respect to the cylinder 1, the extension side chamber R1 is reduced by the displacement of the extension side piston 3, and the compression side is compressed by the displacement of the compression side piston 4. Room R2 is expanded. Then, the check valve 7 which is the extension side rectifying section EC closes, and the extension side chamber R1 and the cooling passage CP communicate with each other only through the notch 7a which is the extension side limiting section ER. Therefore, the gas passes from the reduced extension side chamber R1 through the notch 7a and the cooling passage CP, opens the check valve 8 which is the compression side rectifying unit CC, and moves to the compression side chamber R2.

Here, during the extension operation of the electromagnetic shock absorber D, the pressure in the extension side chamber R1 increases due to the pressure loss generated when the gas passes through the notch 7a which is the extension side limiting portion ER. However, the cooling passage CP is communicated with the compression side chamber R2 through the compression side rectifying unit CC, and the pressure in the cooling passage CP becomes almost the same as the pressure in the compression side chamber R2 expanded by the extension operation of the electromagnetic shock absorber D. .. Therefore, when the electromagnetic shock absorber D is extended, the pressure of the gas until it passes through the notch 7a which is the extension side limiting portion ER is high, and it passes through the notch 7a which is the extension side limiting portion ER. The pressure of the gas that reaches the cooling passage CP becomes low pressure. When the gas passes through the extension side limiting portion ER and reaches the cooling passage CP in this way, the pressure of the gas drops at once and the volume of the gas expands, so that the gas temperature drops. Therefore, the temperature in the cooling passage CP is lowered, and the armature E facing the cooling passage CP can be cooled by the temperature lowering of the gas.

Further, when the electromagnetic shock absorber contracts, the piston rod 2 moves downward in FIG. 1 with respect to the cylinder 1, the compression side chamber R2 is reduced by the displacement of the compression side piston 4, and the extension side piston 3 is displaced. The extension chamber R1 is enlarged. Then, the check valve 8 which is the compression side rectifying section CC closes, and the compression side chamber R2 and the cooling passage CP are communicated with each other only through the notch 8a which is the compression side limiting section CR. Therefore, the gas passes through the notch 8a and the cooling passage CP from the reduced compression side chamber R2, opens the check valve 7 which is the extension side rectifying unit EC, and moves to the extension side chamber R1. Here, during the contraction operation of the electromagnetic shock absorber D, the pressure in the compression side chamber R2 rises due to the pressure loss generated when the gas passes through the notch 8a which is the compression side limiting portion CR. However, the cooling passage CP is communicated to the extension chamber R1 through the extension side rectifying section EC, and the pressure in the cooling passage CP is almost the same as the pressure in the extension chamber R1 expanded by the contraction operation of the electromagnetic shock absorber D. Become. Therefore, when the electromagnetic shock absorber D contracts, the pressure of the gas until it passes through the notch 8a, which is the compression side limiting portion CR, is high, and the gas passes through the notch 8a, which is the compression side limiting portion CR, to pass through the cooling passage. The pressure of the gas that reaches CP becomes low pressure. When the gas passes through the pressure side limiting portion CR and reaches the cooling passage CP in this way, the pressure of the gas drops at once and the volume of the gas expands, so that the gas temperature drops. Therefore, the temperature in the cooling passage CP is lowered, and the armature E facing the cooling passage CP can be cooled by the temperature lowering of the gas.

Since the pressure in the extension side chamber R1 and the pressure in the compression side chamber R2 are different due to the expansion / contraction operation of the electromagnetic shock absorber D, a damping force that hinders the expansion / contraction operation of the electromagnetic shock absorber D is generated. Further, since the electromagnetic shock absorber D includes the linear motor LM, the thrust generated by the linear motor LM can be used as a damping force for suppressing the expansion / contraction operation to function as a damper, and the thrust of the linear motor LM is positive. It can also be expanded and contracted to function as a couture.

As described above, the electromagnetic shock absorber D of the present invention is slidably inserted into the non-magnetic cylinder 1, the piston rod 2 movably inserted into the inner circumference of the cylinder 1, and the cylinder 1. An extension piston 3 provided on the piston rod 2 to partition the extension chamber R1 in the cylinder 1, and a piston that is slidably inserted into the cylinder 1 and is axially spaced from the extension piston 3. A tubular armor E and a cylinder 1 mounted between the compression side piston 4 provided on the rod 2 and partitioning the compression side chamber R2 in the cylinder 1 and the extension side piston 3 and the compression side piston 4 of the piston rod 2. A linear motor LM provided on the outer periphery and having a tubular field F facing the armature E, a gas filled in the extension side chamber R1 and the compression side chamber R2, and a cooling passage CP facing the armature E. The extension side limiting portion ER that communicates the extension side chamber R1 to the cooling passage CP and resists the flow of gas from the extension side chamber R1 to the cooling passage CP, and the extension side chamber R1 communicates with the cooling passage CP and from the cooling passage CP. The extension side rectifying unit EC that allows only the flow of gas toward the extension side chamber R1 and the compression side limiting unit CR that communicates the compression side chamber R2 with the cooling passage CP and gives resistance to the gas flow from the compression side chamber R2 toward the cooling passage CP. And the compression side rectifying unit CC that communicates the compression side chamber R2 to the cooling passage CP and allows only the flow of gas from the cooling passage CP to the compression side chamber R2.

In the electromagnetic shock absorber D configured in this way, when the gas moves back and forth between the extension side chamber R1 and the compression side chamber R2 via the cooling passage CP during expansion and contraction operation, the pressure in the cooling passage CP is always the extension side chamber R1 and the compression side. The pressure on the low pressure side of the chamber R2 becomes equal, and the gas that has entered the cooling passage CP from the chamber on the high pressure side of the extension side chamber R1 and the compression side chamber R2 expands and the temperature drops, so that it faces the cooling passage CP. The armature E can be effectively cooled.

As described above, in the electromagnetic shock absorber D of the present invention, the armature E can be sufficiently cooled during the expansion / contraction operation, so that it is not necessary to limit the amount of current applied to the winding 12 to a small size, and a large thrust can be exhibited even in a small size. .. Therefore, according to the electromagnetic shock absorber D of the present invention, it is possible to avoid an increase in size and reduce the weight and cost while obtaining a large thrust.

Further, in the electromagnetic shock absorber D of the present embodiment, the armature E has a cylindrical core 11 having a plurality of annular slots 11a on the outer periphery thereof, and a winding 12 mounted on the slot 11a. The cooling passage CP is formed by an annular gap between the outer circumference of the piston rod 2 and the inner circumference of the core 11. In the electromagnetic shock absorber D configured in this way, since the cooling passage CP is formed by the annular voids on the inner circumference of the core 11, the entire inner circumference of the core 11 can be exposed to the gas whose temperature has dropped. The child E can be cooled evenly and evenly in the circumferential direction. The cooling passage CP may be provided inside the core 11 in addition to being formed by an annular gap between the piston rod 2 and the core 11, but the cooling passage CP is provided with the piston rod 2 and the core 11. If the armature E is formed with an annular gap between the two, there is an advantage that the armature E can be cooled without bias, the structure of the core 11 is simplified, and processing for providing the cooling passage CP becomes unnecessary.

Further, in the electromagnetic shock absorber D of the present embodiment, since the core 11 has a cylindrical heat sink 11b on the inner circumference, the heat sink 11b can be exposed to the gas passing through the cooling passage CP, and the heat sink 11b can be wound efficiently. The wire 12 and the core 11 can be cooled.

Further, in the electromagnetic shock absorber D of the present embodiment, the core 11 is provided with a ventilation hole 11c that opens from the outer periphery and leads to the cooling passage CP. Since the cooling passage CP, the annular gap between the armature E and the cylinder 1 are communicated with each other through the ventilation hole 11c, the wound having a reduced temperature wraps around the outer circumference of the armature E and generates heat. 12 can be directly exposed to gas. Therefore, according to the electromagnetic shock absorber D of the present embodiment, the armature E can be cooled more effectively, so that a large thrust can be easily obtained, and the electromagnetic shock absorber D can be further miniaturized.

Further, in the electromagnetic shock absorber D of the present embodiment, the extension side limiting unit ER and the extension side rectifying unit EC are an annular check valve 7 having a notch 7a provided in the extension side piston 3, and the compression side limiting unit CR. The compression side rectifying unit CC is an annular check valve 8 provided with a notch 8a provided in the compression side piston 4. According to the electromagnetic shock absorber D configured in this way, the extension side limiting unit ER, the extension side rectifying unit EC, the compression side limiting unit CR, and the compression side rectifying unit CC each have an annular check valve 7 having a short axial length. Since it is composed of, and 8, it is easy to secure the stroke length of the electromagnetic shock absorber D.

Although the preferred embodiments of the present invention have been described in detail above, they can be modified, modified, and modified as long as they do not deviate from the claims.

1 ... Cylinder, 2 ... Piston rod, 3 ... Extension side piston, 4 ... Pressure side piston, 7 ... Check valve (extension side rectifying part), 8 ... Check valve (pressure side rectification) Part), 7a ... notch (extension side limiting part), 8a ... notch (compression side limiting part), 9 ... back yoke, 10a, 10b ... permanent magnet, 11 ... core, 11a ...・ ・ Slot, 11b ・ ・ ・ Heat dissipation plate, 11c ・ ・ ・ Vent hole, 12 ・ ・ ・ Winding, CC ・ ・ ・ Pressure side rectifying part, CP ・ ・ ・ Cooling passage, CR ・ ・ ・ Pressure side limiting part, D.・ ・ Electromagnetic shock absorber, E ・ ・ ・ armature, EC ・ ・ ・ extension side rectifier part, ER ・ ・ ・ extension side limit part, F ・ ・ ・ field magnet, LM ・ ・ ・ linear motor, R1 ・ ・ ・ extension Side chamber, R2 ... compression side chamber

Claims (5)

Non-magnetic cylinder and
A piston rod that is movably inserted into the inner circumference of the cylinder,
An extension piston that is slidably inserted into the cylinder and is provided on the piston rod to partition the extension chamber in the cylinder.
A compression-side piston that is slidably inserted into the cylinder and is provided on the piston rod at an axial distance from the extension-side piston to partition the compression-side chamber in the cylinder.
A linear motor having a tubular armature mounted between the extension-side piston and the compression-side piston of the piston rod, and a tubular field magnet provided on the outer periphery of the cylinder and facing the armature. When,
The gas filled in the extension side chamber and the compression side chamber,
The cooling passage facing the armature and
An extension side limiting portion that communicates the extension side chamber with the cooling passage and imparts resistance to the flow of gas from the extension side chamber to the cooling passage.
An extension side rectifying unit that communicates the extension side chamber with the cooling passage and allows only a gas flow from the cooling passage to the extension side chamber.
A compression side limiting portion that communicates the compression side chamber with the cooling passage and imparts resistance to the flow of gas from the compression side chamber to the cooling passage.
An electromagnetic shock absorber comprising the compression side rectifying unit that communicates the compression side chamber with the cooling passage and allows only the flow of gas from the cooling passage to the compression side chamber. The armature has a cylindrical core having a plurality of annular slots on the outer circumference thereof, and a winding wire mounted in the slots.
The electromagnetic shock absorber according to claim 1, wherein the cooling passage is formed by an annular gap between the outer circumference of the piston rod and the inner circumference of the core. The electromagnetic shock absorber according to claim 2, wherein the core has a cylindrical heat sink on the inner circumference. The electromagnetic shock absorber according to claim 2 or 3, wherein the core has a ventilation hole that opens from the outer circumference and leads to the cooling passage. The extension-side limiting portion and the extension-side rectifying portion are annular check valves provided with notches provided in the extension-side piston.
The electromagnetic shock absorber according to any one of claims 1 to 4, wherein the compression side limiting portion and the compression side rectifying portion are annular check valves provided with a notch provided in the compression side piston.

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