JP2832164B2 - Linear actuator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear actuator, and more particularly, to a linear actuator in a housing.
And a slide rod that performs linear motion.
Related to a near actuator. 2. Description of the Related Art In recent years, with the technical development of automatic machines represented by robots, the importance of linear actuators for performing accurate linear motion has been increasingly recognized and revealed. In particular, linear actuators for transferring workpieces of assembly robots that require high positioning accuracy are being widely used. [0003] As described above, these linear actuators are not only accurate in positional accuracy, but also reliable, have a long life, are compact, have a uniform operating force, can easily change the moving direction, and have high bending rigidity. Etc. are required. [0004] To meet these requirements, various linear actuators have been conventionally proposed. An example is an apparatus disclosed in Japanese Patent Publication No. 56-14883. In this prior art linear actuator,
A linear ball bearing is disposed in the longitudinal direction of the inner circumference of the housing, and a slide rod in which a cylinder is incorporated in contact with the bearing is disposed, and the slide rod is slid in the axial direction. Are provided with a plurality of orifices, and an operating force is applied to the slide rod by hydraulic pressure or pneumatic pressure or the like to achieve positional accuracy and smooth sliding. [0005] The present invention is, however, hydraulic or pneumatic or the like in a linear actuator according to the prior art
Since a control device is required, the overall size of the device increases,
In addition, their hydraulic or pneumatic controls are expensive
Various disadvantages are inherent, such as economical difficulties
doing. SUMMARY OF THE INVENTION The present invention has been made to overcome all of the above-mentioned disadvantages, and has a simple structure.
By braking the shoe, the entire device can be downsized,
Another object of the present invention is to provide a linear actuator capable of reducing the manufacturing cost . [0007] In order to achieve the above object, the present invention provides a housing, in which a plurality of coil units and a magnetic body as an iron core are provided, and the coil unit and the magnetic body are provided. A linear actuator, in which a slide rod penetrating through is disposed so as to be relatively displaceable relative to the housing, is made of a magnetic material, and has a sectoral cross section corresponding to a part of the outer peripheral surface of the slide rod having a circular cross section. A plurality of brake shoes which are integrally formed with each other and are disposed at predetermined intervals along the circumferential direction of the slide rod, one end of which is engaged with each of the plurality of brake shoes, and the other end of which is formed of iron. A plurality of spring members respectively locked to a core, wherein when the alternating current is not supplied to the coil unit, the plurality of brakes are provided via the elastic force of the spring member. Are pressed against the outer peripheral surfaces of the slide rods to brake the slide rods. On the other hand, when an alternating current is applied, the plurality of brake shoes are pressed against the elastic force of the spring member by the attraction force generated in the iron core. The braking of the slide rod is released by moving away from the outer peripheral surface of the slide rod. According to the present invention, a slide rod having a circular cross section is provided.
Is formed integrally in a fan-shaped cross section corresponding to a part of the outer peripheral surface of
Brake shoes and one end of the brake shoes
キ に に そ れ ぞ れ 他 端
A plurality of spring members to be engaged and engaged, and a coil unit
When the alternating current is not supplied to the
The plurality of brake shoes are connected to the slide block via force.
The slide rod is controlled by pressing against the outer surface of
On the other hand, when an alternating current flows,
The plurality of brake shoes are moved by the spring portion due to a suction force.
Away from the outer peripheral surface of the slide rod against the elasticity of the material
The brake on the slide rod is released
You. As described above, according to the present invention, the fan-shaped section is formed.
A plurality of brake shoes and the brake shoes
A plurality of spring members to be pressed against the ride rod
With this, the slide rod is controlled with a simple configuration.
Operating, miniaturizing the entire device and reducing manufacturing costs
Is done. Next, preferred embodiments of a linear actuator according to the present invention will be described in detail with reference to the accompanying drawings. [0010] Figure 1 is a real施例of the present invention, shows a perspective view of a linear actuator having a single slide rod. That is, in FIG. 1, reference numeral 10 indicates a linear actuator,
Basically it comprises a rectangular housing 12, made of a conductor such as aluminum or copper, the housing 12
Ru is constituted from the slide rod 14 that is provided to be freely displaced relative to the. The housing 12 has contacts 16 a to 16 c for inputting electric signals mounted on a terminal block 18. A plurality of rectangular mounting surfaces 19 are formed at both ends along the longitudinal direction of the slide rod 14. On the other hand, FIG.
Shows a longitudinal cross-sectional view along the axial direction of 0. In FIG.
The same components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. Therefore, in FIG. 2, reference numerals 20a to 20n denote brake shoes made of a magnetic material, and the brake shoes 20a to 20n each have a spring portion.
It is engaged to one end of the timber 22a to 22n, the spring member the other end of the 22a-22n iron core 2 made of a magnetic material
4 locked. The doughnut-shaped coils 26 a to 26 f are embedded in the iron core 24 and are housed in the housing 12. Next, a rectangular cap member 28 is engaged with both ends of the housing 12, and a ring member 29 is fitted in a circular hole defined in the center of the cap member 28. The slide rod 14 is inserted into a hole defined in the ring member 29. Here, a linear ball bearing may be provided in the hole of the ring member 29 in which the slide rod 14 fits, if necessary. Although not shown, the donut-shaped coils 26a to 26f are connected to the electrical signal input contacts 16a to 16c after being connected in a predetermined connection mode described later. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. In this figure, the brake shoe 20 in this embodiment is shown.
It is appreciated that the four surfaces constituting the cross Men'ogi shape. The linear actuator 10 according to the embodiment of the present invention is basically configured as described above. Next, the operation and effects of the linear actuator 10 will be described. As can be easily understood from FIGS. 1 to 3, in the linear actuator 10 according to the present embodiment, the slide rod 14 and the housing 12 are slidable with each other. That is, in this embodiment, the housing 1
Whether to fix the 2 or the slide rod 14 can be appropriately selected according to the needs of the user. In this case, the other component can be used as a moving body with respect to the fixed component. It is. Here, for convenience of explanation, it is assumed that the housing 12 is fixed to a fixed body (not shown). Incidentally, in the configuration in which the donut-shaped coils 26a to 26f are arranged on the inner periphery of the housing 12 shown in FIG. 2, an electromagnetic force may be applied to the slide rod 14 in order to move the slide rod 14 right and left. This is possible by passing an appropriate alternating current through the donut-shaped coils 26a-26f. Therefore, the action direction of the electromagnetic force induced by passing an appropriate alternating current through the donut-shaped coils 26a to 26f will be considered. First, the donut type coil 26a shown in FIG.
To 26f are connected as shown in FIG. 4a. In the circuit connection diagram of FIG. 4A, reference numerals 40a to 40l denote fuses that melt at a predetermined temperature, and protect the linear actuator 10 from burning of the coil.
Since these are not the gist of the present invention, they will not be described in detail. Here, in order to make the above connection easier to understand, the circuit connection diagram is rearranged and arranged as shown in FIG. 4B.
As can be easily understood from the circuit connection diagram of FIG.
This circuit is a circuit equivalent to a Δ-connection load in three-phase alternating current. Therefore, as shown in FIG.
6c is connected to a symmetric three-phase AC power supply 36. Here, the reference symbol E represents the ground of the symmetric three-phase AC power supply 36. Next, magnetic flux interlinking direction of the relative sliding rod 14 when the current from the symmetrical three-phase AC power supply 36 is energized toroidal coil 26a-26f, likewise occurs slide rod 14 The direction of the generated eddy current and the direction of the electromagnetic force generated by the magnetic flux and the eddy current, so-called Lorentz force, will be described. In the symmetric three-phase alternating current, if the period of an arbitrary one-phase power is T, the electromotive forces of the other phases have the same waveform and have a time T.
The same process is repeated with a delay of / 3, 2T / 3. Therefore, now, assuming that T = 3t ₁ , time t ₁ , 2t ₁ ,
If Shimese a magnetic field orientation caused by toroidal coil 26a-26f in time 3t ₁ macroscopically, represented by the direction of magnetic field lines drawn upwardly in FIG. 4a. In the direction diagram of the magnetic field drawn in the upper part of FIG. 4a, the symbol S represents the south pole of the magnet, and the symbol N represents the north pole of the magnet. The arrow drawn between the S pole and the N pole indicates the direction of the line of magnetic force. At this time, first, since the magnetic poles forming the lines of magnetic force appear on the iron core 24, the brake shoes 20a to 20n and the like made of the magnetic material by the magnetic poles resilience the spring members 22a to 22n. It is sucked by the iron core 24 against the force . The brake shoes 20a to 20n and the like are separated from the slide rod 14 by this suction action, so that the slide rod 14 becomes slidable. On the other hand, as can be easily understood from the direction of the magnetic field lines drawn in the upper part of FIG.
Since moving along a fourth axis direction, this time, eddy current is generated in a substantially spiral shape with the sliding rod 14. In this case, the slide rod 14 receives an electromagnetic force in the axial direction, and as a result, the performing linear motion in the axial direction. In addition, the moving direction, moving speed,
The moving distance and the like can be easily controlled by preparing a three-phase power supply reversing switch and a power supply device with variable voltage and frequency. When power is not supplied,
The brake shoes 20a to 20n, etc.
Slide rod is pressed under the action of ~ 22n elastic force
14 are pressed against the outer peripheral surfaces. As a result,
The id rod 14 is braked. As described above, according to the present invention, a simple
Device by braking slide rod by configuration
The overall size can be reduced and the manufacturing cost can be reduced.
it can.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a linear actuator according to the actual施例of the present invention. FIG. 2 shows an axial direction of the linear actuator shown in FIG.
Is a longitudinal cross-sectional view taken along. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2; FIG. 4 is a schematic electric circuit diagram for driving a linear actuator. [Description of Signs] 10 Linear actuator 12 Housing 14 Slide rods 16a to 16c
... Contact 20 ... Brake shoes 22a-22n
... Spring member 24 ... Iron core 26a-26f
... Coil 36 ... Symmetric three-phase AC power supply

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-49-138611 (JP, A) Japanese Utility Model Showa 49-138314 (JP, U) Japanese Utility Model Showa 52-84608 (JP, U) Japanese Utility Model Showa 53- 12506 (JP, U) Actually open 1986-117590 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02K 41/00-41/06

Claims (1)

(57) [Claims] A linear actuator in which a plurality of coil units and a magnetic material as an iron core are disposed in a housing, and a slide rod penetrating the coil unit and the magnetic material is disposed so as to be relatively displaceable with respect to the housing. A plurality of slide rods each made of a magnetic material are integrally formed in a sector shape corresponding to a part of the outer peripheral surface of the slide rod having a circular cross section, and are arranged at a predetermined angle apart in the circumferential direction of the slide rod. A brake shoe, and a plurality of spring members, one end of which is respectively engaged with the plurality of brake shoes, and the other end of which is locked to the iron core. In some cases, the plurality of brake shoes are respectively pressed against the outer peripheral surface of the slide rod via the elastic force of the spring member to brake the slide rod. On the other hand, when the alternating current is supplied, the plurality of brake shoes are separated from the outer peripheral surface of the slide rod against the resilience of the spring member by the attraction force generated in the iron core, thereby braking the slide rod. A linear actuator characterized by being released.