JP2950305B2 - Vibration compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration type compressor for compressing a gas by reciprocating a piston, and more particularly to a method for maintaining a neutral position of a piston and stabilizing the operation.

[0002]

2. Description of the Related Art Conventionally, a free displacer type Stirling refrigerator is known as a kind of small refrigerator which generates cryogenic temperature. This refrigerator includes a vibration-type compressor that compresses gas and an expander that expands gas discharged from the compressor.

As a vibration type compressor, for example, Japanese Patent Laid-Open No. 6-1
As disclosed in U.S. Pat. No. 74321, an opposed piston type (double piston type) is known. As shown in FIG. 8, the opposed-piston type compressor has a hermetically sealed housing (101), a cylinder (103) arranged in the housing (101), and a reciprocating cylinder in the cylinder (103). A pair of pistons (107), (107) which are fitted so as to be able to define a compression space (108) in the longitudinal center of the cylinder (103).
And linear motors (115) and (115) as drive sources for reciprocatingly driving the pistons (107) and (107). Also,
The compression space (108) is connected to an expander (not shown) via a gas passage (109) and a connecting pipe (not shown). Each of the linear motors (115) has a driving magnet (116) composed of an annular permanent magnet disposed around the cylinder (103). The magnet (116) allows the cylindrical motor concentric with the center of the cylinder (103). A magnetic field is generated in the space (magnetic gap). In this space, a bobbin (117) integrally fixed to the piston (107) at the center is provided.
A drive coil (118) composed of an electromagnetic coil is wound around the outer periphery of (7). Further, a housing facing the back side of each of the pistons (107) and the open end of the cylinder (103).
(101) A coil spring (125) for elastically supporting the piston (107) so that it can reciprocate between the inner wall and the inner wall.
Has been erected. Drive coil (1) of linear motor (115)
18), a bobbin (117) and an integral part of the bobbin (117) are supplied by an electromagnetic force acting between the current generated by the drive coil (118) and the magnetic field passing through the space formed by the magnet (116). Drive piston (107) to move both pistons (10
7,107) are reciprocated in the cylinder (103) so as to approach and separate from each other. As a result, a predetermined period of gas pressure is generated in the compression space (108).

On the other hand, although not shown, the expander has a cylindrical cylinder, in which a free displacer for partitioning the inside of the cylinder into an expansion space and a working space is fitted reciprocally. The displacer is filled with a regenerator (regenerative heat exchanger), and the regenerator communicates with the expansion space and the working space, respectively. A coil spring for elastically supporting the displacer so as to be able to reciprocate is disposed in the working space. Further, the working space is connected to the compression space (108) of the compressor through the connection pipe, and the gas is expanded from the expansion space by reciprocating the displacer by the gas pressure from the compressor. The cold head at the tip generates cold.

In the above-described vibration type compressor, the piston (107) is provided with a bobbin (117) (more specifically, a drive coil (11)
8) etc.) to form a movable part, and this movable part is suspended by a coil spring (125) so as to reciprocate based on the neutral position. It is used as a resonance spring for the purpose of efficiently reciprocating the movable part. That is, the coil spring (12) is set so that the resonance frequency matches the power supply frequency.
5) The spring constant and so on are set.

However, in such a structure in which the movable portion is elastically supported by the coil spring (125) as an elastic member, the coil spring (125) is in a defective state at the time of assembly, and the coil spring (125) and the movable portion are not connected to each other. There is a problem that the behavior, performance, service life, etc. of the compressor are adversely affected due to the eccentric state during the operation, the repetitive stress of the coil spring (125), and the like. Therefore, setting and adjusting the spring constant and the like of the coil spring (125) has been extremely troublesome in order to eliminate such adverse effects.

Therefore, in order to solve such a problem, the present inventors have proposed to adjust the neutral position of the movable portion by using an electromagnetic force, as described later (Japanese Patent Application No. Hei 9-1997).
229717). That is, a pair of auxiliary coils are provided on both sides of the drive coil, and in addition to the current supplied to the drive coil, a DC current is supplied to the auxiliary coil to generate an electromagnetic force that reciprocates with respect to a predetermined neutral position. It is to be applied to the movable part. This makes it possible to avoid troublesome settings such as the spring constant, and to use a coil spring (125) with a weak spring constant or
Became unnecessary.

[0008]

However, as the auxiliary coil also moves with the reciprocation of the movable part, a back electromotive force is generated in the auxiliary coil. If the influence of the back electromotive force is reduced, the performance of the compressor can be further improved and the life thereof can be prolonged.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and it is an object of the present invention to reduce the effect of the back electromotive force, thereby increasing the accuracy of the neutral position maintaining function of the auxiliary coil, and improving the compressor. The purpose of the present invention is to promote the stabilization of the operation of the device and the extension of its life.

[0010]

In order to achieve the above object, the present invention increases the resistance of a circuit relating to an auxiliary coil and reduces the value of a current generated by a back electromotive force.

More specifically, the invention as defined in claim 1 provides a piston (3) fitted to the cylinder (3) so as to define a compression space (8) in the cylinder (3). (7), one of the cylinder (3) and the piston (7) constitutes a fixed part, and the other constitutes a movable part (20) relatively moved with respect to the fixed part by a linear motor (15). The linear motor (15) is provided with a driving magnet (16) provided on one of the fixed part and the movable part (20), and provided on the other of the fixed part or the movable part (20). A driving coil (18) positioned in a magnetic field generated by a driving magnet (16), wherein the gas is periodically compressed in the compression space (8). ) Is applied to the movable part (2) by an electromagnetic force so that the movable part (2)
0), at least one pair of auxiliary coils (28a to 28d)
A neutral position biasing mechanism (27) is provided on the side of the fixed or movable part (20) where the drive coil (18) is provided, and at least one of the auxiliary coils (28a to 28d) is provided. The two are connected in series with each other.

According to the above-mentioned invention specifying matter, the linear motor (1
When an alternating current of a predetermined frequency is supplied to (5), the movable part (20) reciprocates at a predetermined cycle with respect to the fixed part, and the gas is periodically compressed in the compression space (8) in the cylinder (3). You. Then, the pair of auxiliary coils (28a to 28d) applies an urging force composed of an electromagnetic force such that the movable portion (20) reciprocates based on the neutral position, and as a result, the movable portion (20) It is held by the fixed part so that it can reciprocate from the neutral position. At this time, back electromotive force is generated in the auxiliary coils (28a to 28d).
Since at least two of (28a to 28d) are connected in series with each other, the resistance value is increased. Therefore,
The value of the current flowing through the auxiliary coils (28a to 28d) decreases,
The effect of back electromotive force is reduced. As a result, the neutral position maintaining function by the neutral position urging mechanism (27) is improved in accuracy, the operation of the compressor is stabilized, and the life of the compressor is extended.

According to a second aspect of the present invention, in the vibration type compressor according to the first aspect, the pair of auxiliary coils of the neutral position urging mechanism (27) are connected to each other in series with the first auxiliary coil. (28a, 28d) and the second auxiliary coil (28b, 28c),
The first auxiliary coil (28a, 28d) and the second auxiliary coil (28b, 28c)
When one of the auxiliary coils is inside the magnetic field of the drive magnet (16), there is a predetermined interval so that the other auxiliary coil is located outside the magnetic field, and the drive coil (18) The movable part (20) is arranged side by side on both sides in the reciprocating direction.

According to the above-mentioned invention specifying matter, the first auxiliary coil
When either (28a, 28d) or the second auxiliary coil (28b, 28c) is inside the magnetic field, the other is outside the magnetic field. Therefore, since no back electromotive force is generated in the auxiliary coil outside the magnetic field, the auxiliary coil serves as a resistor that increases the resistance value of a circuit related to the auxiliary coil inside the magnetic field. Therefore, the value of the current flowing through the auxiliary coil inside the magnetic field is close to the ideal current value when there is no back electromotive force, and the effect of the back electromotive force is reduced.

According to a third aspect of the present invention, in the vibration type compressor according to the first aspect, while the cylinder (3) forms a fixed portion, the piston is fitted in the cylinder (3) in a state of facing the inside. The linear motor comprises a first piston (7) and a second piston (7) mounted thereon, and constitutes movable parts (20, 20), respectively. The linear motor comprises the first piston (7) and the second piston (7). And a first linear motor (15) and a second linear motor (15) corresponding to the first and second pistons (7, 7). Is the first piston
(7) a first auxiliary coil (28a) and a second auxiliary coil for applying an urging force consisting of an electromagnetic force for urging the reciprocating motion to a neutral position.
(28b) and a third auxiliary coil (2) for applying an urging force consisting of an electromagnetic force for urging the second piston (7) to a neutral position in a reciprocating motion.
8c) and a fourth auxiliary coil (28d) in order.
The auxiliary coil (28a) and the second auxiliary coil (28b), the third auxiliary coil (28c) and the fourth auxiliary coil (28d), the first auxiliary coil (28a) and the third auxiliary coil (28c), or Second
At least one pair of the auxiliary coil (28b) and the fourth auxiliary coil (28d) is connected in series with each other.

According to the above-mentioned invention specific matter, both movable parts (20, 2
0) come and go in synchronization with each other, so that one movable part (20)
The vibration caused by the reciprocating motion is canceled by the reciprocating motion of the other movable portion (20) that moves in synchronization with the opposite direction, and the vibration of the compressor is reduced. Further, since the auxiliary coil in the magnetic field and the auxiliary coil outside the magnetic field are connected in series, the influence of the back electromotive force is reduced.

According to a fourth aspect of the present invention, a cylinder (3) and a piston (7) fitted into the cylinder (3) so as to define a compression space (8) in the cylinder (3) are provided. One of the cylinder (3) and the piston (7) constitutes a fixed part, and the other constitutes a movable part (20) relatively moved with respect to the fixed part by a linear motor (15).
(15) is a drive magnet (16) provided on one of the fixed portion or the movable portion (20), and the drive magnet (16) provided on the other of the fixed portion or the movable portion (20). And a drive coil (18) positioned in a magnetic field by the compression space (8), wherein the gas is periodically compressed in the compression space (8). At least one pair of auxiliary coils (28a to 28d) for applying an urging force composed of an electromagnetic force to the movable portion (20) so as to be urged to the neutral position includes a fixed portion or a movable portion (2).
0) of the auxiliary coil (2) provided on the side where the drive coil (18) is provided to constitute the neutral position urging mechanism (27).
8a to 28d) and a power supply (92) for supplying current to the auxiliary coil (28a to 28d).
28d), an additional resistor (93) is provided.

The auxiliary coil (28a
The resistance of the circuit according to .about.28d) increases by the amount of the additional resistor (93). Therefore, the value of the current flowing through the auxiliary coils (28a to 28d) approaches the ideal current value when there is no back electromotive force, and the effect of the back electromotive force is reduced.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> -Structure of Compressor (A)-FIG. 1 shows a vibration type compressor (A) for a Stirling refrigerator according to a first embodiment of the present invention. This compressor (A) constitutes a refrigerator in combination with a conventionally known free displacer type expander (not shown).

The compressor (A) has a closed cylindrical housing (1) extending horizontally and horizontally. This housing
(1) comprises a cylindrical wall portion (1a) having a center line in the left-right direction, and disk wall portions (1b, 1b) for hermetically closing both ends of the cylindrical wall portion (1a). The housing (1) includes a fixed member (3) constituting a cylinder and a pair of pistons (7, 7) forming a compression space (8) between the fixed member (3). The movable member (20) is accommodated.

The fixed side member (3) of the present embodiment comprises a yoke member (4).
, A cylinder member (5) and a pair of magnet support members (6, 6) are integrally assembled.

The yoke member (4) is a substantially cylindrical member whose outer peripheral surface is fixed to the inner surface of the cylindrical wall (1a) of the housing (1).
The yoke member (4) has a large-diameter portion (4a) abutting against the inner surface of the cylindrical wall portion (1a) and a small-diameter portion (4b) located at a substantially central portion in the axial direction.
And a pair of connecting portions (4c, 4c) for connecting the large diameter portion (4a) and the small diameter portion (4b). The inner diameter (dimension t1 in FIG. 2) of the small diameter portion (4b) is set to be larger than the outer diameter of the piston (7) by a predetermined dimension. In addition, this small diameter part (4
A protruding portion (5a) of a cylinder member (5) to be described later, which protrudes toward the inner circumferential side, can be in contact with one end edge in the axial direction (left edge in FIG. 1) of the inner peripheral surface of b). A contact portion (4d) is formed. The inner diameter (dimension t2 in FIG. 2) of the contact portion (4d) is set slightly larger than the outer diameter of the piston (7). As a result, the small-diameter portion (4
A concave fitting part (4e) is formed by b) and the contact part (4d).

The cylinder member (5) is a cylindrical member whose inner diameter (dimension t3 in FIG. 2) substantially matches the outer diameter of the piston (7). The outer diameter of the cylinder member (5) matches the inner diameter (t2) of the contact portion (4d) of the yoke member (4). A projection (5a) is formed at a substantially central portion in the axial direction of the cylinder member (5). The outer diameter of the protrusion (5a) matches the inner diameter (t1) of the small diameter portion (4b) of the yoke member (4).

Each magnet support member (6, 6) is a cylindrical member that supports a drive magnet (16, 16) of each linear motor (15, 15) described later. The inner diameter of the magnet support member (6) matches the outer diameter (t2) of the cylinder member (5). The outer diameter (dimension t4 in FIG. 2) of the magnet support member (6) is set so as to have a predetermined distance from the inner surface of the large diameter portion (4a) of the yoke member (4). I have. A step (6a) for supporting the drive magnet (16) is formed on the outer peripheral surface of the magnet support member (6). In particular, the one end edge (left edge in FIG. 1) of the right magnet support member (6) in FIG. 1 is provided only on the inner peripheral side and is in contact with the contact portion (4d) of the yoke member (4).
A holding portion (6b) for holding the projecting portion (5a) of the cylinder member (5) is formed integrally with the cylinder member (5). The outer diameter of the holding portion (6b) is the inner diameter (t) of the small diameter portion (4b) of the yoke member (4).
It matches 1).

The shape of each of the members (4, 5, 6) is set as described above, and the protrusion (5a) of the cylinder member (5) has a contact portion (4d) of the yoke member (4). The right magnet support member (6) has a holding portion (6b) with a cylinder member (5).
Is mounted on the cylinder member (5) and the yoke member (4) such that the protrusion (5a) of the yoke member is pressed down toward the contact portion (4d) of the yoke member (4). That is, the protrusion (5) of the cylinder member (5)
a) is sandwiched between the contact portion (4d) of the yoke member (4) and the sandwiching portion (6b) of the magnet support member (6). The stationary member (3) is configured in this manner, and the cylinder member (5)
The piston fitting hole (11) will be formed inside the.

Further, the yoke member (4) and the magnet support member
(6) is made of a magnetic material such as pure iron, and constitutes a yoke (yoke) for forming a magnetic circuit. On the other hand, the cylinder member (5) is made of a sliding material that reduces the coefficient of friction with the piston (7).

A pair of left and right substantially cylindrical pistons (7, 7) are slidably fitted in the cylinder member (5) with their distal ends facing each other. , 7) surrounded by the cylinder member (5) is the compression space (8).
It has been. A gas passage (9) penetrating in the radial direction is formed in a part of the protrusion (5a) of the cylinder member (5). The inner end of the gas passage (9) is always in communication with the compression space (8). One end of a communication pipe (10) is inserted into the cylindrical wall (1a) of the housing (1) and the small diameter section (4b) of the yoke member (4), and the communication pipe (10) is connected to the gas passage (9). ). Thus, the compression space (8) communicates with an expander (not shown) through the communication pipe (10). Also, this connecting pipe (10)
An O-ring is provided between the cylinder member (5) and the distal end of the cylinder member (5) to prevent fluid leakage from between the outer peripheral surface of the communication pipe (10) and the cylinder member (5). The connecting pipe (10) is provided with a flange (10a), and the flange (10a) is in contact with the outer peripheral surface of the cylindrical wall (1a) of the housing (1). This contact portion is also provided with an O-ring to prevent fluid leakage.

The left and right pistons (7, 7) are drivingly connected to linear motors (15, 15) as drive sources for reciprocating the respective pistons (7, 7). Each of these linear motors
(15) has a drive magnet (16) formed of an annular permanent magnet fitted and fixed to the step (6a) of the magnet support member (6), and includes a magnet support member (6) and a yoke member ( 4) as a yoke, a magnetic field (static magnetic field) of a predetermined strength is applied to a magnetic gap formed by the space between the outer peripheral surface of the driving magnet (16) and the inner peripheral surface of the large diameter portion (4a) of the yoke member (4). generate.

Each of the pistons (7) has a flange portion (7a) extending radially outward from the back side thereof, that is, from the end opposite to the center of the fixed member (3). A cylindrical bobbin (17) serving as a drive unit of the linear motor (15) is integrally connected to the outer periphery of the flange portion (7a) at the base end thereof. The bobbin (17) extends concentrically with the piston (7) toward the center of the housing, and has a tip portion which is connected to the outer peripheral surface of the driving magnet (16) and the inner peripheral surface of the large diameter portion (4a) of the yoke member (4). Are arranged so as to be able to reciprocate in the left-right direction in the magnetic gap therebetween. A drive coil (18) composed of an electromagnetic coil is wound around the outer periphery of the bobbin (17) near the front end at a position corresponding to the drive magnet (16). A movable member (20) is constituted by the bobbin (17) and the piston (7) (including the entire movable parts such as the drive coil (18) and auxiliary coils (28a to 28d) described later). Movable member
(20) is movable relative to the fixed member (3). In addition, each drive coil (18) is
(1) are connected to a drive power supply via a pair of drive current introduction terminals (not shown) which are supported in an insulated state on each of the disk wall portions (1b), and the drive power supply supplies the two linear motors (15, 15). An alternating current of a predetermined frequency is supplied through each drive current introduction terminal in synchronization with the drive coils (18, 18) of the drive coils (18, 18), so that the two pistons (7, 7) move in opposite directions so as to contact and separate from each other at the resonance frequency. It is configured to reciprocate to generate a gas pressure of a predetermined cycle in the compression space (8).

Each piston (7) is a coil spring.
Supported by (30). See Housing
A support member (31) for supporting the coil spring (30) is attached to the disk wall (1b) of (1). The support member (31) includes a shaft portion (31a) having a small-diameter cylindrical shape,
A flange portion (31b) formed at an axially outer end of the shaft portion (31a), and the flange portion (31b) is
Fastened to the inner surface of (1b). A spring stopper (31c) is screwed to the tip of the shaft (31a). On the other hand, a cylindrical spring stopper (17a) is formed at the inner peripheral end of the bobbin (17). Grooves for mounting the coil spring (30) are formed on the outer peripheral surfaces of the spring stopper (31c) and the spring stopper (17a). The coil spring (30) is connected to the shaft (31
a) and one end of the spring stopper (31)
c), the other ends are respectively attached to the spring stoppers (17a). That is, the coil spring (30) is installed between the support member (31) and the bobbin (17), and the fixed side is located at the distal end inside the piston (7), and the movable side is the piston (7). Located on the proximal side of the interior. As a result, the piston (7) is elastically supported.

Further, in the compressor (A), each movable member (20)
There is provided a neutral position urging mechanism (27) that applies an urging force composed of an electromagnetic force to the movable member (20) so that the movable member (20) reciprocates with respect to the fixed side member (3) based on a predetermined neutral position. This neutral position urging mechanism (27) is a bobbin for each linear motor (15).
(17) A pair of auxiliary coils composed of electromagnetic coils wound adjacent to the left and right sides of the drive coil (18) at predetermined positions on the outer periphery
(28a, 28b, 28c, 28d). That is, the pair of auxiliary coils (28a, 28b, 28c, 28d) are juxtaposed on both sides of the drive coil (18) in the reciprocating direction of the movable member (20). And, between a pair of auxiliary coils (28a, 28b, 28c, 28d),
A predetermined interval is provided so that when one of them is inside the magnetic field generated by the driving magnet (16), the other is located outside the magnetic field. That is, the left linear motor (15) shown in FIG. 1 is provided with a first auxiliary coil (28a) on the left side of the drive coil (18) and a second auxiliary coil (28b) on the right side of the drive coil (18). Is provided. The right side linear motor (15) shown in FIG. 1 is provided with a third auxiliary coil (28c) on the left side of the drive coil (18) and the fourth auxiliary coil (28c) on the right side of the drive coil (18).
An auxiliary coil (28d) is provided. And between the first auxiliary coil (28a) and the second auxiliary coil (28b), and
Between the auxiliary coil (28c) and the fourth auxiliary coil (28d),
A predetermined interval slightly longer than the length of the driving magnets (16, 16) is provided.

As a feature of this embodiment, each linear motor
A pair of auxiliary coils (28a, 28b; 28c, 28d) provided in (15)
Are connected in series. Specifically, the first
The auxiliary coil (28a) and the second auxiliary coil (28b) are connected in series with each other, and a pair of energizing current introduction terminals (not shown) are supported by the left disk wall (1b) of the housing (1) in an insulated manner. ) Is connected to a DC power supply (not shown). The third auxiliary coil (28c) and the fourth auxiliary coil (2c
8d) are connected in series with each other, and are connected to a DC power supply (not shown) via an energizing current introduction terminal (not shown) similarly penetratingly supported by the right disk wall (1b). Then, the auxiliary coils (28a to 28a) of each linear motor (15) are
d) to supply a DC current by applying a DC voltage to
An urging force consisting of an electromagnetic force acting between the current generated by the auxiliary coils (28a to 28d) and the magnetic field generated by the driving magnet (16) of the linear motor (15) is applied to the movable member (20). Each movable member (20) is reciprocated with respect to the cylinder (3) based on a predetermined neutral position.

-Operation of Compressor (A)-Next, the operation of this embodiment will be described. With the start of operation of the refrigerator, both linear motors (15,
An alternating current of a predetermined frequency is synchronously supplied from the driving power supply to the driving coil (18, 18) of (15). Along with this energization, both movable members (20, 20) consisting of a bobbin (17) and a piston (7) are generated by the action between the magnetic fields of the drive coil (18) and the drive magnet (16).
Reciprocate from the neutral position in opposite directions so as to approach and separate from each other, and the volume of the compression space (8) increases and decreases due to the contact and separation of the pistons (7, 7). A pressure wave of a predetermined cycle is generated. Since the compression space (8) communicates with the expander through the connecting pipe (10), the displacer in the expander reciprocates at the same cycle as the pressure wave in the compression space (8) and moves in the expansion space. Due to the expansion of the gas, cold occurs, and the reciprocating movement of the displacer cools the cold head at the tip of the cylinder to an extremely low temperature.

At this time, the movable members (20, 20) are held by a neutral position urging mechanism (27) so as to be able to reciprocate based on the neutral position. That is, a DC current is supplied from a DC power supply to the auxiliary coils (28a to 28d) wound around the bobbin (17) of each linear motor (15), so that the auxiliary coils (28a to 28d) are supplied.
Due to the interaction between the current flowing through 28d) and the magnetic field of the drive magnet (16) of the linear motor (15), each of the auxiliary coils (28a to 28d) exerts a force in the direction pushed out of the magnetic gap by the drive magnet (16). receive.

For example, the movable member (20) reciprocates from the neutral position by driving the linear motor (15), and as shown in FIG. 3 (a), the first auxiliary coil (28) moves forward.
When a) moves in the magnetic field, the movable member (20) is urged in the backward direction by the force received by the first auxiliary coil (28a). Conversely, as shown schematically in FIG. 3 (b), when the movable member (20) moves in the backward direction and the second auxiliary coil (28b) moves in the magnetic field, the second auxiliary coil (28b) The movable member (20) is urged in the forward movement direction by the force received.

As described above, the movable member (20) is urged together with the auxiliary coils (28a to 28d) in the direction of being pushed out of the magnetic field by the force received by each of the auxiliary coils (28a to 28d). Is driven to a predetermined neutral position for reciprocating motion.

At this time, the auxiliary coil (28a
Back electromotive force is generated in .about.28d). Therefore, the auxiliary coil
(28a to 28d) changes under the influence of the back electromotive force.

Here, when the auxiliary coils (28a to 28d) are connected in parallel to the DC power supply, the change in the DC current is relatively large, so that the neutral position urging mechanism (2
7) The function of maintaining the neutral position is apt to deteriorate. For example, the first
When the auxiliary coil (28a) moves into the magnetic field,
As shown in (a), when the voltage of the DC power supply is E, the voltage due to the back electromotive force is Ea (t), and the resistance value of the first auxiliary coil (28a) is Ra, the current flows through the first auxiliary coil (28a). Current I
a1 is

[0040]

(Equation 1)

## EQU1 ## Therefore, the current Ia when no back electromotive force is generated, that is,

[0042]

(Equation 2)

Compared with the current value, the current value changes by Ea (t) / Ra.

However, in this embodiment, the first auxiliary coil
Since (28a) is connected in series with the second auxiliary coil (28b), as shown in FIG. 4B, the second auxiliary coil (28b)
Is Rb, the current Ia2 flowing through the first auxiliary coil (28a) is

[0045]

(Equation 3)

Is as follows. At this time, the influence of the back electromotive force is E
a (t) / (Ra + Rb). Since Ra + Rb> Ra, Ea (t) / Ra> Ea (t) / (Ra + R
b). Therefore, the current flowing through the first auxiliary coil (28a) is reduced in the influence of the back electromotive force, and is closer to the ideal current value Ia when no back electromotive force is generated.

-Effects of this embodiment- As described above, in this embodiment, a pair of auxiliary coils (28a, 2
8b; 28c, 28d) are connected in series, so that the resistance value of the circuit related to the auxiliary coil (28a, 28b; 28c, 28d) increases. Therefore, a change in current caused by the back electromotive force can be reduced. Therefore, the neutral position urging mechanism (27) is hardly affected by the back electromotive force, and the function of maintaining the neutral position is maintained at a high level. As a result, the operation of the compressor (A) can be further stabilized, and its life can be prolonged.

Further, since the pair of movable members (20, 20) are moved in and out of synchronization with each other by the linear motors (15, 15) connected to each other, the vibration accompanying the reciprocating motion of each movable member (20) is reduced. Are offset by the reciprocating motion of the other movable member (20) which moves synchronously in the opposite direction. Therefore, generation of vibration of the compressor (A) can be reduced.

The compressor (A) of the present embodiment is a type in which the present invention is applied to a horizontal type in which a piston (7, 7) reciprocates in a horizontal direction. It is also possible to apply the present invention to a vertical type in which) reciprocates vertically.

<Embodiment 2> FIG. 5 shows Embodiment 2 of the present invention.
The present invention is applied to a single-piston vibration compressor in which a movable member (20) moves in a vertical direction. Here, differences from the first embodiment will be described.

The compressor (A) of the present embodiment has a housing
(1) has a vertical centerline, and a fixed side member (3) is disposed below the housing (1) with a vertical centerline. The fixed-side member (3) of this embodiment is also composed of a yoke member (4), a cylinder member (5), and a magnet support member (6), similarly to the first embodiment.
The protruding part (5a) formed on (5) is in contact with the yoke member (4).
These three members are integrated by being sandwiched between the holding member (6) of the magnet supporting member (6) and the holding member (6). A communication pipe (10) is inserted through the center of the yoke member (4) and the cylinder member (5), and this communication pipe (10) connects the compression space (8) to an expander (not shown). A first auxiliary coil (28a) is provided above the drive coil (18), and a second auxiliary coil (28b) is provided below the drive coil (18). The first auxiliary coil (28a) and the second auxiliary coil (28b) are connected in series with each other, and are connected to a DC power source (not shown) via an energizing current introduction terminal (not shown).

According to such a configuration, the effect of reducing the influence of the back electromotive force can be obtained as in the first embodiment.

In this embodiment, the compressor (A) in which the present invention is applied to a vertical type in which the piston (7) reciprocates in the vertical direction is used, but the piston (7) reciprocates in the horizontal direction. It is also possible to apply the present invention to a moving horizontal type.

<Embodiment 3> Embodiment 3 is based on Embodiment 1.
All auxiliary coils (28
a, 28b, 28c, 28d) are connected in series. That is, the first auxiliary coil (28a), the second auxiliary coil (28b), the third auxiliary coil (28c), and the fourth auxiliary coil (28d) are connected in series.

Therefore, as shown in FIG. 6, the first auxiliary coil (28a), the second auxiliary coil (28b), and the third auxiliary coil (28)
c) and the resistance of the fourth auxiliary coil (28d) is Ra,
Rb, Rc, Rd, DC voltage E, first auxiliary coil
(28a) and the voltage due to the back electromotive force generated on the second auxiliary coil (28b) side, and the voltage due to the back electromotive force generated on the third auxiliary coil (28c) and the fourth auxiliary coil (28d) side. Is Ed (t), the DC current Ia ′ flowing through each of the auxiliary coils (28a to 28d) is

[0056]

(Equation 4)

Is as follows. Therefore, it is possible to suppress the effect of the back electromotive force applied to the neutral position urging mechanism (27), and the value of the current flowing through each of the auxiliary coils (28a to 28d) is determined by the current value when no back electromotive force is generated. You can get closer.

Fourth Embodiment As shown in FIG. 7, in the fourth embodiment, an additional resistor (93) is provided between the DC power supply (92) and each of the auxiliary coils (28a to 28d) in the first embodiment. It is provided.

With such a configuration, the auxiliary coil (28a
Since the resistance of the circuit according to -28d) further increases, the change in the current value due to the back electromotive force can be further reduced. Therefore, the effect of the back electromotive force can be further suppressed.

The additional resistor (93) may be provided outside the compressor (A) or may be provided inside the compressor (A).

The auxiliary coils (28a to 28d) are connected to a DC power supply (9
2) Each auxiliary coil is connected in parallel to
(28a to 28d) may be provided with an additional resistor (93).

Further, all the auxiliary coils (28a to 28d) may be connected in series, and an additional resistor (93) may be provided thereon.

<Other Embodiments> Instead of the series connection of each pair in the first embodiment, a first auxiliary coil (28a) and a third auxiliary coil (28c) may be connected in series. Further, the second auxiliary coil (28b) and the fourth auxiliary coil (28d) may be connected in series. Also in this case, when one of the auxiliary coils connected in series is inside the magnetic field, the other auxiliary coil is located outside the magnetic field, and the effect of the back electromotive force can be reduced.

As an application of the third embodiment, a connection method as shown in FIG. 9 may be used. That is, the first auxiliary coil
(28a) and the fourth auxiliary coil (28d) are connected in series,
The auxiliary coil (28b) and the third auxiliary coil (28c) are connected in parallel and then connected in series. In such a connection method, the auxiliary coil close to the compression chamber (8),
Since the half current of the first auxiliary coil (28a) and the fourth auxiliary coil (28d) flows through the auxiliary coil (28b) and the third auxiliary coil (28c), the neutral position is slightly shifted from the compression chamber (8). Can be far away. Further, for the same reason as in the third embodiment, the effect of the back electromotive force applied to the neutral position urging mechanism (27) can be reduced. Thus, when the input power is larger than the rated power, the effect of the back electromotive force applied to the neutral position urging mechanism (27) is reduced while avoiding collision between the movable portion and the fixed portion on the compression chamber side. be able to.

In the above embodiment, each movable member (20) has one
Although only a pair of auxiliary coils, that is, two auxiliary coils, are provided, three or more auxiliary coils may be provided on the movable member (20). For example, two pairs of auxiliary coils may be formed on the movable member (20) using four auxiliary coils. In this case, the effect of the back electromotive force can be reduced by connecting at least two or more auxiliary coils in series.

In the above-described embodiment, the cylinder constitutes the fixed part and the piston constitutes the movable part. However, as long as the gas can be periodically compressed in the compression space, either the cylinder or the piston may be the movable part. It may be. The configuration may be such that the cylinder forms a movable part and the piston forms a fixed part.

[0067]

As described above, according to the first aspect of the present invention, since the auxiliary coil is connected in series, the resistance value of the circuit relating to the auxiliary coil becomes large, so that the current value due to the back electromotive force is increased. Change is small. Therefore, the influence of the back electromotive force is reduced, and a current near the ideal current value when no back electromotive force is applied flows to the auxiliary coil. Therefore, the function of maintaining the neutral position by the neutral position urging mechanism can be made more precise, and the operation of the compressor can be stabilized and the life can be extended.

According to the second aspect of the present invention, when one of the pair of auxiliary coils connected in series is inside the magnetic field, the other is located outside the magnetic field. Therefore, no back electromotive force is generated in the auxiliary coil outside the magnetic field, and the auxiliary coil acts as an additional resistance of a circuit related to the auxiliary coil inside the magnetic field. Therefore, the resistance value of the circuit relating to the auxiliary coil can be easily increased, and the effect of the back electromotive force can be effectively reduced.

According to the third aspect of the present invention, a pair of movable parts are arranged facing each other, and the linear motor is driven so that the two movable parts are moved in and out in synchronization with each other. In addition, the vibration caused by the reciprocating motion of one movable portion can be offset by the reciprocating motion of the other movable portion, and the vibration of the compressor can be reduced. Therefore, the operation of the compressor can be further stabilized. At this time, the effect of the back electromotive force is reduced because the auxiliary coil in the magnetic field and the auxiliary coil outside the magnetic field are connected in series.

According to the fourth aspect of the invention, the resistance value of the circuit relating to the auxiliary coil increases by the amount of the additional resistance. Therefore, the value of the current flowing through the auxiliary coil can be approximated to the ideal current value when there is no back electromotive force, and the effect of the back electromotive force can be suppressed. Therefore, the function of maintaining the neutral position by the neutral position urging mechanism can be made more precise, and the operation of the compressor can be stabilized and the life can be extended.

[Brief description of the drawings]

FIG. 1 is a sectional view of a vibration compressor according to a first embodiment.

FIG. 2 is a diagram for explaining dimensions of each member constituting a fixing member.

FIGS. 3A and 3B are schematic diagrams illustrating the operation of a neutral position urging mechanism.

FIGS. 4A and 4B are circuit diagrams of a circuit relating to an auxiliary coil.

FIG. 5 is a diagram corresponding to FIG. 1 showing a vibration type compressor according to a second embodiment.

FIG. 6 is a diagram corresponding to FIG. 4, showing a vibration type compressor according to a third embodiment.

FIG. 7 is a configuration diagram of a vibration compressor according to a fourth embodiment.

FIG. 8 is a sectional view showing a conventional example of a vibration type compressor.

FIG. 9 is a diagram corresponding to FIG. 4 in another embodiment.

[Explanation of symbols]

 (1) Housing (7) Piston (8) Compression space (15) Linear motor (16) Drive magnet (18) Drive coil (20) Movable member (27) Neutral position biasing mechanism (28a) to (28d) Auxiliary coil (30) Coil spring (93) Additional resistance

Claims (4)

(57) [Claims] A cylinder (3) and a piston (7) fitted in the cylinder (3) so as to define a compression space (8) in the cylinder (3); Alternatively, one of the pistons (7) constitutes a fixed part, while the other is a movable part (2) relatively moved with respect to the fixed part by a linear motor (15).
The linear motor (15) includes a driving magnet (16) provided on one of the fixed part and the movable part (20), and a driving magnet (16) provided on one of the fixed part and the movable part (20). A drive coil (18) provided in the magnetic field of the drive magnet (16), wherein the gas is periodically compressed in the compression space (8). At least one pair of auxiliary coils (28a to 28d) for applying an urging force composed of an electromagnetic force to the movable portion (20) so that the movable portion (20) is biased to the neutral position of the reciprocating motion is fixed or movable. Department
(20) is provided on the side where the drive coil (18) is provided to constitute a neutral position urging mechanism (27), and at least two of the auxiliary coils (28a to 28d)
A vibratory compressor characterized by being connected in series with each other. 2. The vibration type compressor according to claim 1, wherein the pair of auxiliary coils of the neutral position urging mechanism (27) are connected to a first auxiliary coil (28a, 28d) connected in series with each other. The first auxiliary coil (28a, 28d) and the second auxiliary coil (28b, 28c).
c) means that when one of the auxiliary coils is inside the magnetic field generated by the drive magnet (16), the drive coil (18) is separated by a predetermined distance so that the other auxiliary coil is positioned outside the magnetic field. ), The vibration type compressor being arranged side by side on both sides of the movable portion (20) in the reciprocating direction. 3. The vibration type compressor according to claim 1, wherein the cylinder (3) constitutes a fixed part, and the piston (1) is fitted in the cylinder (3) in a state of being opposed to the cylinder (3). 7) and a second piston (7),
The linear motor (15) includes a first linear motor (15) and a second linear motor (15) corresponding to the first piston (7) and the second piston (7). The neutral position urging mechanism (27) urges the first piston (7) to a neutral position in a reciprocating motion. A first auxiliary coil (28a) and a second auxiliary coil (28b) for applying an urging force comprising
A third auxiliary coil (28c) and a fourth auxiliary coil (28d) for applying an urging force comprising an electromagnetic force for urging the piston (7) to a neutral position in a reciprocating motion; ) And the second auxiliary coil (28b), the third auxiliary coil (28c) and the fourth auxiliary coil (28d), the first auxiliary coil (28a) and the third auxiliary coil (28c), or the second auxiliary coil. (28b) and at least one pair of the fourth auxiliary coil (28d) are connected in series with each other. 4. A cylinder (3) comprising a cylinder (3) and a piston (7) fitted in said cylinder (3) so as to define a compression space (8) in said cylinder (3). Alternatively, one of the pistons (7) constitutes a fixed part, while the other is a movable part (2) relatively moved with respect to the fixed part by a linear motor (15).
The linear motor (15) includes a driving magnet (16) provided on one of the fixed part and the movable part (20), and a driving magnet (16) provided on one of the fixed part and the movable part (20). A drive coil (18) provided in the magnetic field of the drive magnet (16), wherein the gas is periodically compressed in the compression space (8). At least one pair of auxiliary coils (28a to 28d) for applying an urging force composed of an electromagnetic force to the movable portion (20) so that the movable portion (20) is biased to the neutral position of the reciprocating motion is fixed or movable. Department
A power supply (92) provided on the side of the drive coil (18) provided with the drive coil (18) to constitute a neutral position urging mechanism (27) and supplying a current to the auxiliary coils (28a to 28d) A vibration-type compressor characterized in that an additional resistor (93) is provided between the auxiliary coil (28a to 28d) and the auxiliary coil (28a to 28d).