JP3117454U - Vibration isolator and Stirling engine using the same - Google Patents

Abstract

An object of the present invention is to prolong the service life of a vibration isolator used in a device that vibrates during operation, such as a Stirling engine.
In a vibration isolator 42 that includes a mass body 37 and a mass body support spring 23 and reduces vibration of a vibration body that is a target for vibration reduction, the mass body support spring is subjected to rust prevention treatment, Prevents rust generated in the mass support spring and extends the life of the vibration isolator.
[Selection] Figure 1

Description

  The present invention relates to a vibration isolator (dynamic vibration absorber) for reducing vibration of a device that generates vibration, and is applied to, for example, a Stirling engine.

FIG. 1 is a cross-sectional view of an example of a free piston type Stirling refrigerator. The Stirling refrigerator is a cylinder 3A arranged in a pressure vessel 4 filled with working gas.
, 3B, and a piston 1 and a displacer 2 that reciprocate on the same axis, and a linear motor 16 that is a drive mechanism for driving the piston 1. Pressure vessel 4
An anti-vibration device 4 for anti-vibration of the device is provided at the end opposite to the cold head 13 in the axial direction.
2 is arranged. The vibration isolator 42 is mainly composed of the mass support spring 23 and the mass 37.
The resonance frequency obtained from the spring constant of the leaf spring 231 and the mass of the system is designed to be the same as the resonance frequency of the vibration system of the piston 1 and the vibration system of the displacer 2. is there. With this configuration, the vibration isolator 4
2, when vibration is generated in accordance with the movement of the piston 1, it resonates by receiving the vibration, converts the vibration energy into heat energy, and is released to the outside from the entire Stirling refrigerator and vibration isolator 42. Vibration energy can be reduced.

The leaf spring 231 used for the vibration isolator 42 is formed as shown in FIG. FIG. 2A is a plan view of an example of the leaf spring 231, and FIG. 2B is a side sectional view thereof. The leaf springs 231 are based on a stainless steel disk having a predetermined diameter and thickness, and are provided at regular intervals so that four spiral slits 232 are repeated in the circumferential direction. Further, bolts 38 are provided. A through hole 233 for insertion is provided in the center of the disk, and further, a through hole 234 for insertion of the fixed shaft 40 is provided on the extension of the outer peripheral side end of the slit 232 corresponding to the number of fixed shafts. It is provided. Processing for arranging the slit 232 and the through holes 233 and 234 is performed by laser processing, for example.

As a result of the above processing, an arm portion 235 is formed between the slits 232 in a spiral shape from the center portion of the disk, and the arm portion 235 forms a disk surface of the disk. It has a predetermined elastic modulus in the vertical direction, that is, in the axial direction.

The shape shown in FIG. 2 is merely an example, and the range of the spring constant of the leaf spring 231 is determined to some extent by the diameter and thickness of the disc, and depends on the shape of one slit 232 and the number of consecutive repetitions thereof. The spring constant can be set to a predetermined value within the range.

In general, stainless steel is a material that is resistant to rust because it forms a non-conductive film with a chromium layer, and does not generate rust even under salt water dripping conditions. Therefore, no rust or the like is generated even if the rust prevention treatment is not performed, and it is not necessary to consider so much deterioration over time. However, when processing is performed using a high temperature such as laser processing or electric discharge processing, the chrome layer in the processing cross section is broken by the heat, and thus rust is likely to occur.

In particular, the leaf spring 23 of the vibration isolator 42 provided outside the Stirling refrigerator.
Since one surface is always in contact with the outside air, red rust is likely to be generated at the edge of the processed cross section, where the rust is deteriorated and the strength is weakened. Further, since the leaf spring of the vibration isolator vibrates violently in the axial direction along with the vibration of the apparatus due to the operation of the Stirling refrigerator, a large stress is repeatedly applied to the base portion 236 of the arm portion 235. Therefore, the portion where the strength is reduced due to the occurrence of red rust generated at the edge portion of the processed cross section in the vicinity develops into a crack, and eventually the fracture occurs. As described above, when the leaf spring 231 is broken, not only the vibration-proofing effect is lost, but also the leaf spring confidence generates abnormal noise, resulting in an increase in vibration and noise of the apparatus.

The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a long-life vibration isolator.

In order to achieve the above object, the present invention includes a mass body and a mass body support spring that supports the mass body, wherein the mass body support is provided in a vibration isolator that reduces vibration of a vibration body that is a vibration reduction target. The vibration isolator is characterized in that the spring is subjected to rust prevention treatment.

Rust prevention coating is suitable for the rust prevention treatment. As other rust prevention treatments, there are a method of removing a portion altered by processing with acid after processing and regenerating the chromium layer, a method of removing a portion altered by processing by polishing the surface after processing and regenerating the chromium layer. However, rust prevention can be most reliably prevented by applying rust-proof coating. In addition, as an antirust coating, the electrodeposition coating of an acrylic resin is used suitably. This is because the acrylic resin has good weather resistance, which can prevent the leaf spring from being rusted for a very long time.

As described above, in the present invention, in the vibration isolator (dynamic vibration absorber) that includes the mass body and the mass body support spring that supports the mass body and reduces the vibration of the vibration body that is the object of vibration reduction,
By subjecting the mass body support spring made of stainless steel to a rust prevention treatment, it is possible to extend the life of the vibration isolator (dynamic vibration absorber).

In addition, a Stirling engine using this can be operated for a long period of time without breaking the vibration isolator.

Hereinafter, as an example of an object to be subjected to vibration isolation using the vibration isolation device, a case where vibration isolation of a free piston type Stirling refrigerator will be described.

FIG. 1 is a cross-sectional view showing an example of a free piston type Stirling refrigerator. This Stirling refrigerator is configured to operate the Stirling cycle and cool the cold head 13 with various configurations arranged in the pressure vessel 4.

Explaining each configuration, the pressure vessel 4 is mainly disposed on the back space 8 side.

It is formed from a vessel 4B and an outer cylinder 3C arranged on the working space 7 side. The vessel 4B is further divided into two structures, the cold head 13 side being the vessel body 4D, and the side facing the cold head 13 side (hereinafter referred to as the vibration isolator side in this specification). In the description of the assembly structure, even when the vibration isolator 42 is not assembled yet, for the convenience of explanation, the term on the vibration isolator side is used on the basis of the state of the finished product. is there.

In the pressure vessel 4, a cylinder 3 </ b> A and a cylinder 3 </ b> B joined with a communication hole 12 </ b> A are disposed. A piston 1 and a displacer 2 that can reciprocate on the same axis as the cylinders 3A and 3B are inserted into the cylinders 3A and 3B. Further, a linear motor 16 that drives the piston 1 is disposed outside the cylinder 3A. Is provided.

The inside of the pressure vessel 4 is roughly divided into two spaces, one of which is a back space 8 mainly surrounded by the vessel 4B and the piston 1, and the other one is mainly the piston 1, the outer cylinder 3C, And a working space 7 surrounded by the cold head 13. The working space 7 is further divided into two spaces by the displacer 2, the space existing between the displacer 2 and the piston 1 is the compression space 9, and the space existing between the displacer 2 and the cold head 13 is the expansion space. 10.

The compression space 9 and the expansion space 10 communicate with each other via a communication path 12 formed between the cylinder 3B and the outer cylinder 3C. In the communication path 12, a high temperature side internal heat exchanger 21 is provided.
The regenerator 11 and the low temperature side internal heat exchanger 22 are arranged in order from the compression space 9 toward the expansion space 10.

The cold head 13 is formed of a high thermal conductivity material such as copper or aluminum in a substantially bottomed cylindrical shape, and the bottom portion 13A faces the opening of the cylinder 3B.
3B is arrange | positioned so that the low temperature side internal heat exchanger 22 may be opposed. The worm head 41 is formed by forming a high thermal conductivity material such as copper or aluminum in a ring shape, and the inner circumference thereof is arranged to face the outer circumference of the high temperature side internal heat exchanger 21.

The piston 1 is a cylindrical structure, and a through hole 1a into which the rod 2a can be inserted is processed at the center axis thereof. Further, the refrigerant compressed by the compression space 9 is used as a refrigerant between the outer peripheral surface of the piston 1 and the cylinder 3A. A gas bearing (not shown) is provided for releasing the gap between them to provide a bearing effect.

The displacer 2 is a cylindrical structure, and is provided with a gas bearing (not shown) that discharges the refrigerant compressed by the compression space 9 to the gap between the outer peripheral surface of the displacer 2 and the cylinder 3B to provide a bearing effect. . A rod 2 a is attached to the surface of the displacer 2 on the piston 1 arrangement side, and the rod 2 a is inserted through the through hole 1 a of the piston 1. A threaded portion 2b is machined at the end of the rod 2a opposite to the displacer 2 side.

The linear motor 16 is mainly composed of a permanent magnet 15 arranged in an annular shape and a permanent magnet 15.
Is comprised of an outer yoke 17A and an inner yoke 17B. The outer yoke 17A is formed by sandwiching a coil 20 wound around a bobbin inside a substantially U-shaped flat iron core that is laminated in a ring shape, and sandwiching it from both sides in the axial direction with a non-magnetic material. 17B is formed by laminating and fixing flat iron cores in an annular shape. Inner yoke 17B and inner circumference of outer yoke 17A
A gap 19 is formed between the outer circumference of the sleeve 14 and the sleeve 14 is formed in the gap 19.

A held permanent magnet 15 is arranged.

The sleeve 14 has a bottomed cylindrical shape, and an annular digging is provided on the inner periphery on the tip side of the peripheral edge portion 14c. Then, the arcuate permanent magnets 15 having a plurality of sides are arranged in an annular shape as a whole. The bottom 14b of the sleeve 14
A through hole into which the rod 2a can be inserted is provided at the center of the boss portion 14a.
Is formed. The piston 1 is disposed on the surface of the bottom 14b on the side where the peripheral edge 14c is arranged.
However, it is adjusted so that the axis of the piston 1 and the center of the bottom portion 14b are arranged coaxially, and is fixed using a fixing means such as a bolt.

A plurality of three or more fixing shafts 24 for fixing the piston support spring 5 and the displacer support spring 6 from the end surface toward the vibration isolator side are provided on the end surface of the outer yoke 17A on the vibration isolator side. For example, 4). This fixed shaft 2
4, a screw is formed on the outer periphery of the nut 4. The nut 25 is screwed so that the upper surface of the nut 25 is substantially flush with the upper surface of the boss portion 14a.

The piston support spring 5 includes two disc-shaped plate springs 51 having the same shape as in FIG.
, 51, and sandwiching the spacer 26 between the two leaf springs 51, 51, the perforated bolt 28 inserted through the center through hole of the leaf spring 51 and the through hole of the spacer 26, and the boss portion 14 a of the sleeve 14. The piston 1 is fixed to the piston support spring 5 by fitting. Through holes are also provided at several locations around the leaf spring 51, the spacer 27 is sandwiched between the leaf springs 51, 51, and fixed to the through hole around the leaf spring 51 and the through hole of the spacer 27. The shaft 24 is inserted.

The displacer support spring 6 is composed of two disc-shaped plate springs 61 and 61 having the same shape as in FIG. 2, and the spacer 30 is sandwiched between the two plate springs 61 and 61.
The displacer 2 is fixed to the displacer support spring 6 by screwing the threaded portion 2b of the rod 2a inserted through the through hole in the center of the leaf spring 61 and the through hole of the spacer 30 and the nut 32. Through holes are provided in several places around the leaf spring 61, the spacer 31 is sandwiched between the leaf springs 61, 61, and a spacer 29 having a predetermined height is placed on the piston support spring 5. The fixed shaft 24 is inserted through the through hole around the leaf spring 61 and the through holes of the spacers 29 and 31.

Finally, the piston support spring 5 and the displacer support spring 6 are incorporated in the Stirling refrigerator by tightening nuts 33 inserted into the fixed shaft 24 from above and below. After the piston support spring 5 and the displacer support spring 6 are assembled in the Stirling refrigerator in this way, necessary connections such as power supply wiring to the linear motor 16 are completed, and the vessel cap 4C is welded and fixed to the vessel body 4D. To do.

A vibration isolator 42 for vibration isolation of the Stirling refrigerator is disposed at the end of the pressure vessel 4 opposite to the cold head 13 in the axial direction. The vibration isolator 42 is mainly composed of a mass body support spring 23 and a mass body 37, and the resonance frequency obtained from the spring constant of the leaf spring 231 and the mass of the system is the vibration system of the piston 1 and the displacer 2. It is designed to be the same as the resonance frequency of the vibration system. By designing in this way, the vibration isolator 42 vibrates violently upon receiving vibration energy based on the operation of the piston 1 and the displacer 2, thereby canceling the vibration energy and consequently the entire Stirling refrigerator. Can be reduced.

The mass support spring 23 is formed of a plate spring 231 having a shape as shown in FIG. 2 as in the conventional case, and a stainless steel disk is laser processed into a shape as shown in FIG. Painted. This rust-proof coating is performed by electrodeposition coating of acrylic resin. Since acrylic resin has excellent weather resistance, it is a very useful coating for rust prevention.

By applying such a rust-proof coating, the surface of the stainless steel is guarded by an acrylic resin coating film having high weather resistance and does not come into direct contact with the outside air, so that an oxide film is not formed and it is resistant to rust. Moreover, since this coating film is electrodeposition-coated, it has an extremely high affinity with the stainless steel surface, and even if it is subjected to repeated stress, it is difficult to crack or peel off, so it has a rust-proofing effect even under severe conditions involving severe plastic deformation. continue.

Therefore, after the stainless steel disk is laser processed to form a leaf spring 231 having a shape as shown in FIG. 2, the above-mentioned antirust coating is applied to the entire leaf spring 231 so that the strength characteristic of the stainless steel is obtained. It was confirmed that the life of the vibration isolator 42 was extended more than 10 times under normal operating conditions of the Stirling refrigerator.

Alternatively, instead of rust-proof coating, a stainless steel disk may be laser processed into a shape as shown in FIG. 2 and then the entire disk may be post-treated with acid.

By performing the post-treatment with acid in this way, the part that has been altered by heat due to laser processing is washed away, and the non-conductive film by the chromium layer is regenerated by the self-regenerating function, so that the leaf spring 231 that is less likely to rust is obtained again. Can do.

In addition to this, it is considered that the surface of the entire disk may be polished after a stainless steel disk is laser processed into the shape shown in FIG.

By polishing the surface in this manner, the portion altered by heat due to laser processing is removed, and the non-conductive film made of the chromium layer is regenerated by the self-regenerating function, so that the leaf spring 231 that is less likely to rust can be obtained again. .

Next, a procedure for incorporating the mass support spring 23 formed by combining such plate springs 231 into the Stirling refrigerator will be described. Incorporation of the mass support spring 23 is
A mounting frame 34 is arranged on the vessel cap 4C, and a plurality of (preferably three or more, four when the leaf spring 231 shown in FIG. This is done by attaching a vibration device 42. The fixed shaft 40
A screw provided with a screw on the outer periphery is used.

FIG. 3 is a partially exploded cross-sectional view showing a process when the vibration isolator 42 is attached to the Stirling refrigerator, and an example of assembly will be described with reference to FIG.
A nut 36 is attached to the fixed shaft 40 as a spacer, and then a plate spring 231 having a bolt 38 inserted in a hole provided in the center in advance is attached to the fixed shaft 40. At this time, the screw side end of the bolt 38 faces the side opposite to the mounting frame 34. Further, spacers 39 and 41 such as nuts or washers are attached to the fixed shaft 40 and the screw portion of the bolt 38. At this time, the spacer 3 attached to the fixed shaft 40
9 and the spacer 41 attached to the bolt 38 are of the same thickness.

After that, the second leaf spring 231 is installed in the center from the side opposite to the mounting frame 34.

The bolts 38 are mounted so that the bolts 38 are inserted into the drilled holes, and the fixed shaft 40 is inserted into the holes arranged at the peripheral edge thereof. Thereafter, the nut 35 is fixed to the fixed shaft 4
The plate spring 231 is fixed by screwing it to 0, and the mass body 37 is screwed and fixed to the screw side end of the bolt 38. Thereby, attachment of the vibration isolator 42 is completed.

In the Stirling refrigerator configured as described above, a refrigerant is sealed in a pressure vessel. This refrigerant can be hydrogen, helium, nitrogen, etc., and is sealed at a high pressure of several tens of atmospheres.

When an alternating voltage is applied to the linear motor 16, the linear motor 16 reciprocates, and the piston 1 also reciprocates accordingly. The displacer 2 reciprocates in a state in which the phase is advanced by about a quarter of the operation of the piston 1 to form a Stirling cycle in the working space 7. As a result, the high temperature side internal heat exchanger 21 is heated to a high temperature, and the low temperature side heat exchanger 22 is cooled to a low temperature.

Heat of the high temperature side internal heat exchanger 21 is transmitted to the worm head 41 and released to the outside, and heat is supplied to the low temperature side internal heat exchanger 22 from the outside via the cold head 13. That is, the cold head 13 is in a very low temperature state when viewed from the outside, and various objects can be cooled by using this low temperature.

As mentioned above, although the application example about the Stirling refrigerator was described in this embodiment, it is not restricted to this, It is provided with a mass body and the mass body support spring which supports the said mass body, and vibration of the vibrating body used as a vibration reduction object The present invention is applicable to all vibration isolators adjusted to have the same resonance frequency as the frequency.

Moreover, although the free piston type Stirling refrigerator has been described as an example, the present invention is not limited to this type, and can be applied to other types of Stirling refrigerators. Furthermore, in general, Stirling refrigerators can be operated with the cycle reversed, in which case they can operate as generators or power generators, but can also be applied to these devices.

The Stirling engine referred to in this specification includes a Stirling refrigerator, a generator,
It is used as a word that means all devices that use a Stirling cycle, such as a power generator.

It is sectional drawing of an example of the free piston type Stirling refrigerator equipped with the vibration isolator which concerns on this invention. (A) is a top view of an example of the leaf | plate spring used for a vibration isolator, (b) is the side surface sectional drawing. It is a partially exploded sectional view which shows the attachment process to the Stirling refrigerator of a vibration isolator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piston 2 Displacer 3A, 3B Cylinder 4 Pressure-resistant container 5 Piston support spring 6 Displacer support spring 8 Back space 9 Compression space 10 Expansion space 11 Regenerator 13 Cold head 14 Sleeve 16 Linear motor 20 Electromagnetic coil 23 Mass body support spring 24,40 Fixed shaft 25, 32, 33, 36 Nut 26, 27, 29, 30, 31, 39, 41 Spacer 28 Perforated bolt 37 Mass body 38 Bolt 42 Vibration isolator 51, 61, 231 Leaf spring

Claims (5)

In a vibration isolator that includes a mass body and a mass body support spring that supports the mass body, and that reduces vibrations of a vibration body that is subject to vibration reduction, the mass body support spring made of stainless steel is subjected to rust prevention treatment. An anti-vibration device characterized by that. The mass body support made of stainless steel formed by laser processing in a vibration isolator that includes a mass body and a mass body support spring that supports the mass body, and that reduces vibration of a vibration body that is a target for vibration reduction. An anti-vibration device characterized by applying anti-rust treatment to the spring. The anti-vibration device according to claim 1 or 2, wherein the antirust treatment is performed by electrodeposition coating of an acrylic resin. The anti-vibration device according to claim 2, wherein the anti-rust treatment is a post-treatment with an acid, and is a treatment for washing away a portion altered by heat by laser processing. A Stirling engine comprising a piston and a displacer inserted into a cylinder and reciprocating on the same axis, and a drive mechanism for driving the piston, and forming a Stirling cycle by the reciprocating movement of the piston. A Stirling engine equipped with the vibration isolator described in 1.

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