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 6 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 on the armature 6 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 6 when the coil 5 is de-excited, and a biasing member 4 which biases the armature 6 toward the disc 7, wherein a wave washer is provided between the field core 2 and the armature 6 as the biasing member 4.

Description

Technical Field

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

Background Art

[0002] Conventionally, a brake device for braking a rotating member has been used in a power transmission mechanism of various industrial equipment. As an example, in the fields of robots, OA equipment, etc., a so-called "non-excitation operation brake" is known, which has a mechanism for generating an electromagnetic attractive force by a coil and performs braking in a state where the coil is non-excited (see Patent Document 1: Japanese Patent Application 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 downsizing and thinning of the non-excitation operation brake have been demanded. However, in a conventional non-excitation operation brake as disclosed in, for example, Patent Document 1, a configuration in which a coil spring is used as a biasing member for generating a braking force (frictional force) is common, and there is a problem that it is difficult to reduce the diameter and thickness due to factors such as the need to secure an installation space for the coil spring.

[0005] On the other hand, in a non-excitation operation brake, if it is simply downsized and thinned, the attractive force becomes small and there is also a problem of securing an installation space, making it difficult to use a biasing member with a strong biasing force. As a result, a new problem has arisen that it is impossible to generate a necessary braking force (frictional force).

Means for Solving the Problems

[0006] This invention has been made in view of the above circumstances, and aims to provide a non-excitation-operated brake that is capable of generating the necessary braking force and is smaller in diameter and thinner.

[0007] As one embodiment, the above problem is solved by the solution disclosed below.

[0008] 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 rotatably supported and connected to an external rotating shaft, which contacts the armature when the coil is de-excited; and a biasing member that biases the armature toward the disc, wherein a wave washer is provided between the field core and the armature as the biasing member.

[0009] Furthermore, the field core has an annular housing portion for housing the spool, and it is preferable that the spool is housed in the housing portion such that the armature-side end face of the spool is recessed relative to the armature-side end face of the field core, thereby forming a recess on the armature side of the housing portion, and the wave washer is disposed in the recess.

[0010] Furthermore, it is preferable that the dimensions of the recess in the axial direction and the movement dimension of the armature are set such that when an attractive force is generated on the armature while the coil is energized, the wave washer is compressed to a state where the axial deflection is not zero, and when the attractive force on the armature disappears while the coil is de-energized, the wave washer is stretched to a state where the axial deflection is not at its maximum.

[0011] Furthermore, it is preferable that the overall outer diameter is 20 mm or less, and the overall axial dimension is 10 mm or less.

[0012] Another example is that multiple wave washers are preferably arranged in the recess in a stacked state with flat washers sandwiched between adjacent ones. [Effects of the Invention]

[0013] 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]

[0014] [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-operated brake. [Figure 4] This is an enlarged view of section IV in Figure 3. [Modes for carrying out the invention]

[0015] 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. Figure 4 is an enlarged view of part IV in Figure 3. 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.

[0016] 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.

[0017] As shown in Figures 1 to 4, the non-excitation-operated brake 1 according to this embodiment comprises a coil 5 around which a power supply line 5B is wound on a spool 5A, and an armature 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 armature 6 when the coil 5 is energized (when the power supply line 5B is energized).

[0018] Furthermore, the de-excitation brake 1 is rotatably supported and connected to an external rotating shaft (not shown), and includes a disc 7 (composed of a base plate 7A and lining 7B described later) to which the armature 6 comes into contact when the coil 5 is de-excited (a state in which the power supply line 5B is not energized and the device is de-excited), and a biasing member 4 that biases the armature 6 toward the disc 7. In this embodiment, the external rotating shaft is connected to the disc 7 (base plate 7A) via a driving boss 10, but a configuration without the driving boss 10 is also possible (not shown).

[0019] Furthermore, the de-excitation brake 1 is equipped with a side plate 9 that engages with the field core 2 and encloses and seals the above-mentioned components. In this embodiment, the disc 7 (lining 7B) is also in contact with the side plate 9 when the coil 5 is de-excited (details will be described later).

[0020] Next, each component will be described in detail. First, the field core 2 has a substantially cup shape that opens at one end (the side plate 9 side to be engaged), specifically a double cylinder structure including an inner cylinder portion 2a and an outer cylinder portion 2b, and has a bottom surface portion 2c that connects the inner cylinder portion 2a and the outer cylinder portion 2b at the other end, and the cross-sectional shape (upper half cross-section and lower half cross-section) is formed in a U shape. The annular space between the inner cylinder portion 2a and the outer cylinder portion 2b becomes a housing portion 2d for housing the coil 5 and the like. According to this configuration, when the annular coil 5 housed in the housing portion 2d is excited (that is, in a state where the energizing wire 5B is energized), the field core 2 becomes magnetic and acts to attract the armature 6. As an example, the field core 2 is formed using a magnetic metal material such as SPCE. In this 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 (not shown).

[0021] Next, the coil 5 has a configuration in which an energizing wire 5B is wound around a 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. An energizing wire 5B made of a metallic conductive material (as an 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 where the energizing wire 5B is energized and excited), a magnetic force is generated, and the surrounding field core 2 acts as an electromagnet, so that an attractive force to the armature 6 is generated. As a result, the armature 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 where 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 that the attractive force to the armature 6 disappears. As a result, the armature 6 moves in a direction away from the field core 2 by the biasing force of the biasing member 4.

[0022] Next, the armature 6 is supported by the field core 2 so as to be movable only in the axial direction, with a plurality of (for example, three) pins 11 erected on one end side of the field core 2 inserted through corresponding notch portions 6a at the peripheral portion. According to this configuration, when the attractive force of the field core 2 is generated by the excitation of the coil 5, the armature 6 moves closer to the field core 2 against the aforementioned biasing force and is adsorbed to the end faces (the faces on one end side) 2e of the inner cylinder portion 2a and the outer cylinder portion 2b. On the other hand, when the attractive force of the field core 2 disappears due to the non-excitation of the coil 5, the armature 6 moves away from the field core 2 by the aforementioned biasing force and abuts against a disk 7 described later (that is, the braking action described later) is obtained. As an example, the armature 6 is formed using a magnetic metal material.

[0023] Next, the disk 7 has a configuration in which a lining 7B is adhered to the disk surface of a disk-shaped base plate 7A. In the present embodiment, the lining 7B is adhered to both the surface of the base plate 7A on the side of the armature 6 and the surface on the side of the side plate 9, and a "double-plate type" configuration is adopted to obtain a braking force (frictional force) by each lining 7B. However, the present invention is not limited to this configuration, and a "single-plate type" configuration in which the lining 7B is adhered only to the surface on the side of the armature 6 may be adopted (not shown). By adopting the "double-plate type" configuration as in the present embodiment, a larger braking force (frictional force) can be obtained compared with the "single-plate type". As an example, the base plate 7A is formed using a non-magnetic metal material such as stainless steel. Further, the lining 7B is formed using a friction material mainly composed of a resin material or a metal material.

[0024] In this 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 armature 6 disappears, and the biasing force of the biasing member 4 causes the armature 6 to move away from the field core 2. At this time, one surface of the armature 6 (the surface on the side plate 9 side) and one surface of the lining 7B of the disk 7 (the surface on the field core 2 side) come into contact. Furthermore, since this embodiment is a "double-plate type," the contact (pushing) by the armature 6 causes the other surface of the lining 7B of the disk 7 (the surface on the side plate 9 side) to come into contact with one surface of the side plate 9 (the surface on the field core 2 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 lining 7B in this embodiment), and a braking effect (i.e., an effect that slows down or stops the rotation of the disc 7 and, consequently, the rotating shaft) 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 armature 6, and the armature 6 moves in a direction toward the field core 2 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.

[0025] 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 (base plate 7A) (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.

[0026] Next, the side plate 9 is formed in a substantially cup shape (with a through hole in the center) with an opening at one end (the side of the field core 2 to which it is engaged), and is configured to house and seal the above-mentioned components inside when engaged with the field core 2. Furthermore, in this embodiment, as described above, when the coil 5 is in an unexcited state, the surface of the lining 7B of the opposing disk 7 (the surface on the side plate 9 side) comes into contact with the inner surface of the side plate 9 (the surface on the field core 2 side), generating a braking force (frictional force). As an example, the side plate 9 is formed using the same metal material as the armature 6.

[0027] Next, the configuration of the biasing member 4, which is characteristic of this embodiment, will be described in detail. Specifically, an annular wave washer is provided as the biasing member 4 between the field core 2 and the armature 6. Specifically, it is positioned between the coil 5 (spool 5A) housed in the housing portion 2d of the field core 2 and the armature 6 so as to fit onto the outer circumference of the inner cylindrical portion 2a of the field core 2. In this embodiment, a spacer 12 made of a hard material (for example, a metal material or a resin material) is interposed between the spool 5A and the biasing member 4 to suppress wear of the spool 5A, but a configuration without the spacer 12 is also possible.

[0028] Here, a "wave washer" is a biasing member that has a structure in which a thin (for example, about 0.2 mm thick or less) annular plate material of a metal material (for example, stainless steel, spring steel, etc.) is bent into a wave shape (forming alternating peaks and valleys on the plate surface) to create deflection. When the deflection is compressed, a restoring force (elastic force) is generated that tries to return it to its original shape, and this is used as a biasing force. The plate thickness and the number of peaks (valleys) are set appropriately according to conditions such as the attractive force generated in the field core 2 and the movement dimension (distance) of the armature 6.

[0029] This configuration makes it possible to solve the problems of conventional non-excitation brakes, such as those disclosed in Patent Document 1. Specifically, in conventional non-excitation brakes, a coil spring is generally used as the biasing member that generates braking force (frictional force), and there was a problem in that it was difficult to reduce the diameter and thickness due to factors such as the need to secure space for the installation of the coil spring. In this embodiment, a configuration was devised in which a wave washer is used as the biasing member 4 instead of a coil spring, making it possible to reduce the overall diameter and thickness. Furthermore, if the diameter and thickness are simply reduced, the suction force will decrease and there will be a problem in securing installation space, making it difficult to use a biasing member with a strong biasing force, and thus it will be impossible to generate the necessary braking force (frictional force). In this embodiment, however, it has been confirmed that the necessary braking force can be sufficiently obtained. In actual verification conducted by the inventors, simulation results were obtained showing that it is possible to achieve an outer diameter of 20 mm or less (for example, 20 mm), an overall length (axial dimension) of 10 mm or less (for example, 9 mm), and a braking force of 0.0010 Nm or more (for example, 0.0012 Nm). Thus, in the case of a non-excitation brake, it has become possible to reduce the diameter and thickness to a degree that was previously difficult to achieve when trying to obtain the required braking force.

[0030] In addition, in the present embodiment, the following characteristic configuration regarding the biasing member (wave washer) 4 is provided. Specifically, the end face 5d of the spool 5A on the armature 6 side is positioned deeper (i.e., closer to the bottom face portion 2c) with respect to the end face 2e of the field core 2 on the armature 6 side, and is configured to be accommodated in the accommodating portion 2d. As a result, a concave portion 2f is formed on the armature 6 side of the accommodating portion 2d. The wave washer 4 is disposed in the concave portion 2f. According to this configuration, the configuration in which a biasing member (in the conventional example, a coil spring) is disposed on the outer cylinder portion 2b of the field core 2 as in the prior art can be eliminated, and thus the outer cylinder portion 2b can be formed thinner. Therefore, in particular, it can greatly contribute to the reduction of the diameter. However, in order to generate the biasing force by the wave washer 4, when the total thickness dimension in the axial direction (not the plate thickness) including the amount of deflection in the wave washer 4 is D1, the thickness dimension (plate thickness) of the spacer 12 is D2, and the depth dimension of the concave portion 2f (the distance between the end face 2e and the end face 5d) is D3, it is necessary to set such that D1 + D2 > D3 and D2 < D3.

[0031] Furthermore, this embodiment includes the following characteristic configuration of the biasing member (wave washer) 4. Specifically, when the coil 5 is energized and an attractive force is generated on the armature 6, the wave washer 4 is compressed to a state where the axial deflection is not zero, and when the coil 5 is de-energized and the attractive force on the armature 6 disappears, the wave washer 4 is extended to a state where the axial deflection is not maximized. The depth dimension D3 of the recess 2f in the axial direction and the movement dimension D4 of the armature 6 are set accordingly. The movement dimension D4 of the armature 6 is the dimension (distance) of movement between the position where the armature 6 is closest to the field core 2 (the position where it is attracted to the field core 2) and the position where the armature 6 is closest to the side plate 9 (the position where the lining 7B of the disk 7 contacts the armature 6 and the side plate 9). This configuration provides the following effects. Specifically, in its original application, a "wave washer" is typically used in a state where deflection is zero (or close to it) and without any change in its state. However, the inventors have found that by using the above configuration, it is possible to use it as a biasing member for a non-excitation-operated brake that performs repeated compression and extension operations, and that it is possible to extend its lifespan.

[0032] In this embodiment, a configuration in which one biasing member (wave washer) 4 is provided has been described as an example, but the invention is not limited to this. That is, as another example, a configuration in which multiple biasing members (wave washers) 4 are provided may be used. In that case, the wave washers 4 may be stacked with flat washers sandwiched between adjacent wave washers 4, and then arranged in the aforementioned recess 2f (depth can be set as appropriate) formed between the spool 5A and the armature 6 in the housing section 2d (not shown). With this configuration, the biasing force applied to the armature 6 can be increased compared to the above example, and therefore the braking force (frictional force) applied by the disc 7 can be increased.

[0033] 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.

[0034] 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]

[0035] 1. Non-excitation brake 2 Field Cores 4. Biasing member (wave washer) 5 coils 6 Armature 7 discs 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 armature comprises a biasing member that biases the armature toward the disk side, As the biasing member, a wave washer is provided between the field core and the armature. A non-excitation-operated brake characterized by the following features.

2. The field core has an annular housing portion for housing the spool, The spool is housed in the housing such that the armature-side end face of the spool is recessed relative to the armature-side end face of the field core, thereby forming a recess on the armature side of the housing, and the wave washer is disposed in the recess. The non-excitation-operated brake according to claim 1, characterized by the above.

3. The dimensions of the recess in the axial direction and the movement dimension of the armature are set such that when an attractive force is generated on the armature while the coil is energized, the wave washer is compressed to a state where the axial deflection is not zero, and when the attractive force on the armature disappears while the coil is de-energized, the wave washer is stretched to a state where the axial deflection is not at its maximum. The non-excitation-operated brake according to claim 2, characterized by the above.

4. The overall outer diameter is 20 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 3, characterized by the above.

5. Multiple wave washers are arranged in the recess in a stacked state with flat washers sandwiched between adjacent ones. The non-excitation-operated brake according to claim 2, characterized by the above.

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