Non-excitation brake

Abstract

The present invention provides a non-excitation-operated brake that can generate the necessary braking force while being smaller in diameter and thinner. [Solution] The present invention provides a non-excitation-operated brake 1 comprising a coil 5 on which a power supply wire 5B is wound around a spool 5A, an armature 6A supported to be movable along the axial direction of the coil 5, a field core 2 which houses the coil 5 and generates an attractive force against the armature 6A when the coil 5 is excited, a disc 7 which is rotatably supported and connected to an external rotating shaft and which contacts the armature 6A when the coil 5 is de-excitation-operated, and a plunger 6B which is supported to be movable along the axial direction within the spool 5A, wherein the armature 6A and the plunger 6B are integrally constructed by molding a single component or by connecting multiple components.

Description

Technical Field

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[0001] The present invention relates to a non-excitation operating brake.

Background Art

[0002] Conventionally, brake devices for braking rotating members have been used in power transmission mechanisms of various industrial equipment. As an example, in the fields of robots, office automation equipment, etc., a so-called "non-excitation operating brake" is known, which has a mechanism that generates an electromagnetic attractive force by a coil and performs braking in a state where the coil is de-energized (see Patent Document 1: Japanese Patent Laid-Open No. 2001-065606).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Recently, the miniaturization of equipment to be mounted has advanced, and the reduction in diameter and thickness of non-excitation operating brakes has been demanded. However, in a conventional non-excitation operating brake as disclosed in, for example, Patent Document 1, if the diameter and thickness are simply reduced, the attractive force becomes small, making it difficult to use a biasing member with a strong biasing force. As a result, a problem has arisen in that the required braking force (frictional force) cannot be generated.

Means for Solving the Problems

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a non-excitation operating brake capable of generating a required braking force and achieving reduction in diameter and thickness.

[0006] As one embodiment, the above problems are solved by the following disclosed solution means.

[0007] The disclosed non-excitation-operated brake comprises a coil on which energizing wires are wound around a spool; an armature supported to be movable along the axial direction of the coil; a field core housing the coil and generating an attractive force on the armature when the coil is excited; a disc supported to be rotatably and connected to an external rotating shaft, and which contacts the armature when the coil is unexcitation-operated; and a plunger supported to be movable within the spool along the axial direction, wherein the armature and the plunger are integrally formed by molding a single component or by connecting multiple components.

[0008] Furthermore, it is preferable to further include a side plate attached to the opening of the field core, wherein the side plate is formed from a resin material and fitted into the opening, and the peripheral wall portion is provided with a notched groove that allows the outer peripheral projection of the armature to be inserted to serve as a guide for movement in the axial direction and as an anti-rotation stopper in the circumferential direction.

[0009] Furthermore, it is preferable that the side plate has a friction plate made of a metal material fixed to its inner surface on the field core side.

[0010] Furthermore, it is preferable that the armature and plunger, which are integrally constructed, have a hollow portion formed at their radial center that penetrates along the axial direction.

[0011] Furthermore, it is preferable that the field core has a double cylindrical outer cylinder portion and an inner cylinder portion, and that one end of the coil is housed between the outer cylinder portion and the inner cylinder portion, and that the end face of the inner cylinder portion of the field core on the plunger side and the end face of the plunger on the inner cylinder portion side are arranged to face each other at the axial center position of the coil.

[0012] Furthermore, it is preferable that the inner diameter of the inner cylinder portion in the field core and the inner diameter of the hollow portion in the armature and plunger are the same dimension, and that a coil spring is disposed between the outer circumferential surface of the inner cylinder portion and the inner circumferential surface of the spool to impart a biasing force to the armature and plunger in the axial direction.

[0013] Furthermore, it is preferable that the overall outer diameter is 10 mm or less, and the overall axial dimension is 10 mm or less. [Effects of the Invention]

[0014] According to the disclosed non-excitation-operated brake, it is possible to generate the necessary braking force while achieving a smaller diameter and thinner profile. [Brief explanation of the drawing]

[0015] [Figure 1] A perspective view showing an example of a non-excitation operated brake according to an embodiment of the present invention. [Figure 2] Figure 1 is an exploded perspective view showing an example of a non-excitation-operated brake. [Figure 3] Figure 1 is a cross-sectional view showing an example of a non-excitation brake. [Modes for carrying out the invention]

[0016] Embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 is a perspective view (schematic diagram) showing an example of a non-excitation operated brake 1 according to an embodiment of the present invention, Figure 2 is an exploded perspective view (schematic diagram) thereof, and Figure 3 is a cross-sectional view (schematic diagram) thereof. In the following, the direction parallel to the central axis C common to the components shown in Figure 2 may be referred to as the "axial direction." Also, in all the figures used to explain the embodiments, components having the same function will be denoted by the same reference numeral, and repeated explanations may be omitted.

[0017] The de-excitation brake 1 according to this embodiment is a device that is incorporated into, for example, a robot, office automation equipment, etc., to brake a rotating member (specifically, a rotating shaft) in a power transmission mechanism. More specifically, it is a so-called "de-excitation type" brake that is equipped with a coil that generates an electromagnetic attractive force and performs braking when the coil is de-excited.

[0018] As shown in Figures 1 to 3, the non-excitation brake 1 according to this embodiment comprises a coil 5 around which a power supply line 5B is wound on a spool 5A, and a movable part 6 supported so as to be movable along the axial direction of the coil 5 (a direction parallel to the central axis C of the spool 5A). It also includes a field core 2 that houses the coil 5 and generates an attractive force on the movable part 6 when the coil 5 is energized (when the power supply line 5B is energized). The movable part 6 according to this embodiment has a configuration in which an armature 6A and a plunger 6B are integrated (details will be described later). Furthermore, the external rotating shaft (not shown) to be braked is configured to enter from the bottom surface 2C side of the field core 2 (i.e., inserted through the field core 2) and is connected to the driving boss 10 described later (however, it may also be configured to enter from the opposite side).

[0019] Furthermore, the de-excitation brake 1 is rotatably supported and connected to an external rotating shaft (not shown), and includes a disc 7 that contacts the movable part 6 when the coil 5 is de-excited (a state in which no current is supplied to the power supply line 5B and the unit is de-excited), and a biasing member 4 (a coil spring described later) that biases the movable part 6 toward the disc 7. In this embodiment, the external rotating shaft is connected to the disc 7 via a driving boss 10, but a configuration without the driving boss 10 is also possible (not shown).

[0020] Furthermore, the no-excitation operation brake 1 is engaged with the field core 2 and includes a side plate 9 that houses and seals the above-described components therein. In the present embodiment, the disk 7 is also configured to abut against a friction plate 8 fixed to the side plate 9 when the coil 5 is in a no-excitation state (details will be described later).

[0021] Subsequently, each component will be described in detail. First, the field core 2 has a substantially cup shape that opens at one end side (the side of the side plate 9 to be engaged), specifically, a double-cylindrical structure including an inner cylinder portion 2A that serves as a fixed core and an outer cylinder portion 2B (however, the total lengths of the inner cylinder portion 2A and the outer cylinder portion 2B are different), and includes a bottom surface portion 2C that connects the inner cylinder portion 2A and the outer cylinder portion 2B at the other end side, and the cross-sectional shape (upper half cross-section and lower half cross-section) is formed in a J shape. The annular space between the inner cylinder portion 2A and the outer cylinder portion 2B serves as a housing portion that houses one end side (about half of the total length in the present embodiment) of the coil 5. Also, the side plate 9 is attached to the opening 2a. According to this configuration, when the annular coil 5 housed in the housing portion is excited (that is, when the energized wire 5B is energized), the field core 2 has a magnetic force and attracts the movable portion 6. As an example, the field core 2 is formed using a magnetic metal material such as SPCE or an iron-based sintered material. In the present embodiment, the inner cylinder portion 2A, the outer cylinder portion 2B, and the bottom surface portion 2C are formed separately and joined by caulking, but the present invention is not limited to this, and they may be integrally formed (by press molding or the like) (not shown).

[0022] Next, the coil 5 has a configuration in which the energizing wire 5B is wound around the spool 5A. Specifically, the spool 5A includes a first ring-shaped portion 5a, a second ring-shaped portion 5b, and a cylindrical portion 5c that connects the first ring-shaped portion 5a and the second ring-shaped portion 5b, and is integrally formed. As an example, the spool 5A is formed using a resin material having electrical insulation properties. The energizing wire 5B made of a metallic conductive material (for example, copper or the like) is wound around the outer peripheral surface of the cylindrical portion 5c of the spool 5A to form the coil 5. According to this configuration, when the coil 5 is in an excited state (a state in which the energizing wire 5B is energized and excited), a magnetic force is generated, and the surrounding field core 2 acts as an electromagnet, so an attractive force to the movable portion 6 is generated. As a result, the movable portion 6 moves in a direction approaching the field core 2 against the biasing force of the biasing member 4 (described later). On the other hand, when the coil 5 is in a non-excited state (a state in which the energizing wire 5B is not energized and is non-excited), the magnetic force disappears, and the surrounding field core 2 does not act as an electromagnet, so the attractive force to the movable portion 6 disappears. As a result, the movable portion 6 moves in a direction away from the field core 2 by the biasing force of the biasing member 4.

[0023] Next, as described above, the movable portion 6 has a configuration in which the armature 6A and the plunger 6B are integrated. In the present embodiment, the armature 6A and the plunger 6B are formed separately and joined by caulking, that is, an integrated configuration is formed by connecting a plurality (in this case, two) of members. However, it is not limited to this, and an integrated configuration by molding (such as cutting) of a single member may also be used (not shown). As an example, the armature 6A and the plunger 6B are formed using the same magnetic metal material (different materials may also be used).

[0024] Here, the armature 6A according to the present embodiment has a configuration in which a plurality (in this case, two locations with a phase difference of 180 degrees) of outer peripheral protrusions 6a (protrusions protruding in the radial direction) are provided on the peripheral edge of an annular member having a predetermined thickness. The outer peripheral protrusion 6a is inserted into a notch groove 9c of a side plate 9 described later and serves functions functions as a movement guide and a rotation stopper.

[0025] On the other hand, the plunger 6B according to this embodiment has a substantially cylindrical shape having a predetermined length in the axial direction, and is configured such that almost the entire portion, excluding the portion connected to the armature 6A, is housed (slidably fitted inside) within the spool 5A.

[0026] According to the above configuration, when an attractive force is generated in the field core 2 by the excitation of the coil 5, the following effects are obtained. Specifically, against the aforementioned biasing force (i.e., when the attractive force of the field core 2 exceeds the biasing force), the movable part 6 (i.e., the integrally configured armature 6A and plunger 6B) moves in a direction approaching the inner cylinder (fixed iron core) 2A due to the attractive force generated in the field core 2.

[0027] On the other hand, when the attractive force of the field core 2 disappears due to the de-excitation of coil 5, the following effect is obtained. Specifically, because there is no attractive force from the field core 2, the movable part 6 (i.e., the integrally constructed armature 6A and plunger 6B) moves away from the inner cylinder (fixed iron core) 2A due to the aforementioned biasing force. As a result, the movable part 6 (in this case, the armature 6A) comes into contact with the disk 7 described later (i.e., for the braking action described later).

[0028] Thus, in this embodiment, by integrating the armature 6A and the plunger 6B to form the movable part 6, the following significant advantages can be obtained compared to the case where the movable part is composed only of an annular armature. Specifically, a configuration can be realized that applies a stronger magnetic circuit, that is, a stronger magnetic force (magnetic attraction force), to the movable part 6, allowing the biasing force setting in the biasing member 4 to be increased. Therefore, the force (pressure) that brings the armature 6A and the disk 7 into contact, that is, the braking force, can be increased, making it possible to reduce the diameter and thickness while ensuring the necessary braking force.

[0029] Furthermore, the movable part 6 (integrated armature 6A and plunger 6B) according to this embodiment has a hollow portion 6c formed at its radial center, extending through it in the axial direction. Moreover, the inner diameter of the hollow portion 6c and the inner diameter of the inner cylinder portion 2A of the field core 2 are configured to be the same dimension (diameter). With this configuration, constraints such as having to form the external rotating shaft that enters from the bottom surface portion 2C of the field core 2 in a stepped shape are not imposed, thus simplifying both the attachment of the rotating shaft to the de-excitation brake 1 and the attachment of the de-excitation brake 1 to the equipment to be mounted.

[0030] Furthermore, in this embodiment, a coil spring is used as the biasing member 4, and the coil spring 4 is arranged between the outer circumferential surface of the inner cylinder portion 2A and the inner circumferential surface of the spool 5A. With this configuration, it is possible to make the inner diameters of the hollow portion 6c and the inner cylinder portion 2A the same. Moreover, since the outer diameter of the coil spring 4 can be maximized within the central space of the spool 5A (i.e., made the same diameter as the outer diameter of the plunger 6B), the plunger 6B (and consequently the integrated armature 6A) can be stably biased (pushed).

[0031] For example, the coil spring 4 is formed using a metal material such as stainless steel or spring steel. The wire diameter and number of turns are set appropriately according to conditions such as the attractive force generated in the field core 2 and the movement dimension (distance) of the movable part 6.

[0032] Furthermore, a characteristic feature of this embodiment is that the end face 6b of the plunger 6B (the end face on the inner cylinder portion 2A side) and the end face 2b of the inner cylinder portion 2A (the end face on the plunger 6B side) are arranged to face each other at the axial center position of the coil 5 (here, the 1 / 2 position in the axial direction and its vicinity). With this configuration, even if a coil spring 4 with a thin wire diameter is used, the overall length (axial dimension) can be secured to a certain extent, and the necessary biasing force can be generated. At the same time, the overall length (axial dimension) of the plunger 6B can be secured to a certain extent, and the necessary suction force can be generated. Therefore, the balance between the biasing force and the suction force can be optimized, and a configuration can be realized in which the necessary braking force (frictional force) can be obtained even when the diameter and thickness are reduced.

[0033] Next, the disc 7 is formed in the shape of a disc of a predetermined thickness using a friction material mainly composed of resin or metal. In this embodiment, a "double-plate" configuration is adopted in which braking force (frictional force) is obtained from both sides, the side facing the movable part 6 and the side facing the side plate 9. By adopting this "double-plate" configuration, a larger braking force (frictional force) can be obtained compared to a "single-plate" configuration (i.e., a configuration in which braking force is obtained from only one side). However, the disc 7 may also be a "single-plate" configuration (not shown). Furthermore, the disc 7 may be composed of multiple members (for example, a configuration in which friction material is attached to a base plate made of metal or the like) (not shown).

[0034] According to the above configuration, when the coil 5 is de-energized and the field core 2 does not act as an electromagnet, the attractive force of the field core 2 on the movable part 6 disappears, and the biasing force of the biasing member 4 causes the movable part 6 to move away from the inner cylinder part 2A. At this time, one surface of the movable part 6 (armature 6A) (the surface on the side plate 9 side) and one surface of the disk 7 (the surface on the inner cylinder part 2A side) come into contact. Furthermore, since this embodiment is a "double-plate type," the contact (pushing) by the movable part 6 (armature 6A) causes the other surface of the disk 7 (the surface on the side plate 9 side) to come into contact with one surface of the friction plate 8 (described later) fixed to the inner surface of the side plate 9 (the surface on the inner cylinder part 2A side). As described later, the disc 7 is connected to an external rotating shaft (not shown) via the driving boss 10. Therefore, when the rotating shaft, i.e., the disc 7, is in a rotating state, a braking force (frictional force) is generated by the above-mentioned contact (contact on both sides of the disc 7 in this embodiment), and a braking effect (i.e., an effect that slows down the disc 7 and, consequently, the rotating shaft, and stops its rotation) can be obtained. On the other hand, when the coil 5 is energized and the field core 2 acts as an electromagnet, an attractive force is generated by the field core 2 on the movable part 6, and the movable part 6 moves in a direction toward the inner cylinder part 2A against the biasing force of the biasing member 4. At this time, the above-mentioned contact does not occur, and therefore no braking effect is obtained.

[0035] Next, the driving boss 10 is formed in a rectangular shape with rounded corners when viewed from the front, corresponding to the shape of the through hole 7a formed at the radial center of the disc 7 (a rectangular shape with rounded corners), and is configured to fit into the through hole 7a. Note that the disc 7 is not completely fixed to the driving boss 10, and is configured to allow a small amount of axial movement (corresponding to the displacement of the disc 7). As mentioned above, an external rotating shaft (not shown) is connected to and fixed to the driving boss 10 (fixing screws and other fasteners are not shown). With this configuration, the rotating shaft and the disc 7 can be connected via the driving boss 10. Therefore, by applying the aforementioned braking force (frictional force) to the disc 7, a braking effect can be obtained that slows down or stops the rotation of the rotating shaft. As an example, the driving boss 10 is formed using a non-magnetic metal material or a resin material. The external rotating shaft is connected to the driving boss 10 from the field core 2 side (i.e., in a configuration that passes through the field core 2), but this is not the only configuration, and it may be connected from the opposite side.

[0036] Next, the side plate 9 is configured to include a ring-shaped portion 9a and a peripheral wall portion 9b extending from the peripheral edge of the ring-shaped portion 9a toward the field core 2. As an example, the side plate 9 is integrally formed using an electrically insulating resin material. In this embodiment, the peripheral wall portion 9b has an intermittent configuration in the circumferential direction (i.e., it is provided only partially, not over the entire circumference), but it may also have a continuous configuration (i.e., it is provided over the entire circumference).

[0037] The side plate 9 is configured to house and seal the above-mentioned components inside while engaged with the field core 2. In this embodiment, the entire side plate 9 is fitted into the opening 2a of the field core 2 (i.e., the outer edge of the side plate 9 fits inside the opening 2a). This configuration makes it possible to reduce the radial diameter of the non-excitation brake 1.

[0038] Furthermore, the peripheral wall portion 9b is provided with a notched groove 9c into which the outer peripheral projection 6a of the armature 6A is inserted and held so as to be movable in the axial direction. With this configuration, the armature 6A can be prevented from rotating in the circumferential direction and guided to move linearly in the axial direction. In this embodiment, the peripheral wall portion of the field core 2 also has a notched groove 2c formed at a position corresponding to the notched groove 9c, and the outer peripheral projection 6a of the armature 6A can be visually observed and manually operated (moved) from the outside.

[0039] In this way, by using a resin material for the side plate 9, it is possible to form a complex shape that enables a lightweight structure and multi-functionality (specifically, fixing to the field core 2, guiding movement and preventing rotation for the armature 6A).

[0040] On the other hand, because the side plate 9 is made of resin, it is not possible to obtain braking force (frictional force) by making contact with the armature 6A. Therefore, in this embodiment, a friction plate 8 made of metal is fixed to the inner surface of the side plate 9 (the surface facing the field core 2) (for example, "adhesion," but other fixing methods are also acceptable). With this configuration, when the coil 5 is in an unexcited state, the surface of the opposing disc 7 (the surface facing the side plate 9) comes into contact with the surface of the friction plate 8 fixed to the inner surface of the side plate 9 (the surface facing the field core 2), thereby obtaining braking force (frictional force). Therefore, even if the side plate 9 is made of resin to realize the above multi-functionality, a "double-plate type" brake can be realized in which both sides of the disc 7 act as linings. For example, the friction plate 8 is made of the same metal material as the armature 6A.

[0041] As mentioned above, in conventional non-excitation brakes, simply reducing the diameter and thickness reduces the attractive force, making it difficult to use a biasing member with a strong biasing force, and thus making it impossible to generate the necessary braking force (frictional force). In response to this problem, it was confirmed that the non-excitation brake 1 having the above configuration can sufficiently obtain the necessary braking force. In actual verification conducted by the inventors, simulation results were obtained showing that a braking force of 0.002 Nm or more (for example, 0.002 Nm) can be achieved with an outer diameter of 10 mm or less (8 mm for example) and an overall length (axial dimension) of 10 mm or less (8 mm for example). Thus, in non-excitation brakes, it has become possible to reduce the diameter and thickness to a degree that was previously difficult to achieve when trying to obtain the necessary braking force.

[0042] As described above, the present invention makes it possible to realize a non-excitation-operated brake that can generate the necessary braking force while achieving a smaller diameter and thinner design.

[0043] It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the scope of the present invention. [Explanation of symbols]

[0044] 1. Non-excitation brake 2 Field Cores 4. Biasing member 5 coils 6 Moving parts 6A Armature 6B Plunger 7 discs 8 friction plates 9 Side Plates 10 Driving Boss

Claims

1. A coil with a live wire wound around a spool, An armature supported so as to be movable along the axial direction of the coil, A field core that houses the coil and generates an attractive force on the armature when the coil is energized, A disk that is rotatably supported and connected to an external rotating shaft, and which contacts the armature when the coil is de-energized, The spool comprises a plunger supported so as to be movable along the axial direction, The armature and the plunger are integrally formed by molding a single component or by connecting multiple components. A non-excitation-operated brake characterized by the following features.

2. The field core further comprises side plates attached to the openings, The side plate is formed from a resin material and fitted into the opening, and the peripheral wall portion is provided with a notched groove that allows the outer peripheral projection of the armature to be inserted to serve as a guide for movement in the axial direction and as an anti-rotation mechanism in the circumferential direction. The non-excitation-operated brake according to claim 1, characterized by the above.

3. The side plate has a friction plate made of a metal material fixed to its inner surface on the field core side. The non-excitation-operated brake according to claim 2, characterized by the above.

4. The armature and plunger, which are integrally constructed, have a hollow portion formed at their radial center that penetrates along the axial direction. The non-excitation-operated brake according to claim 1, characterized by the above.

5. The field core has a double cylindrical outer cylinder portion and an inner cylinder portion, and is configured such that one end of the coil is housed between the outer cylinder portion and the inner cylinder portion. The end face of the inner cylinder portion of the field core on the plunger side and the end face of the plunger on the inner cylinder portion side are configured to face each other at the central position in the axial direction of the coil. The non-excitation-operated brake according to claim 4, characterized by the above.

6. The inner diameter of the inner cylinder portion in the field core and the inner diameter of the hollow portion in the armature and plunger are configured to be the same dimension. A coil spring is disposed between the outer circumferential surface of the inner cylinder and the inner circumferential surface of the spool, thereby applying a biasing force to the armature and the plunger in the axial direction. The non-excitation-operated brake according to claim 5, characterized by the above.

7. The overall outer diameter is 10 mm or less, and the overall axial dimension is 10 mm or less. A non-excitation-operated brake according to any one of claims 1 to 6, characterized by the above.

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