JP7719356B2 - Electromagnetic brake - Google Patents

Description

The present invention relates to an electromagnetic brake that is widely used for braking rotating objects, etc.

A known electromagnetic brake is a non-excitation type that generates braking force using the torque of a coil spring (see, for example, Patent Document 1).

As shown in Figure 11, Patent Document 1 discloses a motor comprising a yoke 1, a coil 2 attached to the yoke 1, and a coil spring 10 attached to the yoke 1. The excitation force of the coil 2 and the spring force of the coil spring 10 allow the armature 4 to move back and forth. When de-excited, the coil spring 10 moves the armature 4, sandwiching the disc 5 between it and the side plate 7, thereby transmitting the braking force of the disc 5 to the motor shaft 11. When excited, electromagnetic force separates the armature 4 from the side plate 7, releasing the motor shaft 11 via the disc 5.

Japanese Patent Application Publication No. 10-220504

By the way, the coil spring of a conventional electromagnetic brake is housed in a flat-bottomed spring hole 1x machined into the yoke 1, as shown in Figure 11.

However, when attempting to insert a coil spring 10 into a spring hole 1x of this shape, the spring hole 1x opens in only one direction (the up and down direction in Figure 11), so the coil spring 10 can only be inserted from that direction. For this reason, the spring insertion work must be carried out strictly by hand or by robot.

With this type of spring housing structure, particularly when inserting the coil spring 10 using a robot, the coordinates of the spring hole 1x, which varies depending on the model, must be individually set on the robot or detected each time, requiring complex settings that hinder the automation of spring insertion work using a robot.

The present invention was developed to address these issues, with the aim of realizing an electromagnetic brake with a structure suitable for automating the coil spring insertion process.

To achieve the above objectives, the present invention takes the following measures:

In other words, the electromagnetic brake of the present invention comprises a yoke, a coil attached to the yoke, and a coil spring attached to the yoke, and switches the brake between ON and OFF states using the excitation force of the coil and the spring force of the coil spring, and is based on the premise that the yoke comprises an inner yoke portion and a spring accommodating portion located on the outer periphery of the inner yoke portion and having a spring hole, and that this spring accommodating portion can be attached to the outer periphery of the inner yoke portion with a coil spring accommodated in the spring hole.

In conventional systems, the spring accommodating portion is integrated with the inner yoke portion to form a yoke. In contrast, with the configuration of the present invention, the coil spring can be placed in the spring hole of the spring accommodating portion before the spring accommodating portion is positioned on the outer periphery of the inner yoke portion. Therefore, by designing the spring accommodating portion in a shape that makes it easy to insert a coil spring, it is possible to eliminate the robotic process of setting and locating the position of the spring hole, and then inserting the coil spring by aiming at the spring hole from the direction of its opening.

In the electromagnetic brake of the present invention, based on the above premise, the spring accommodating portion is preferably elongated like a rod, has a spring hole opening at one side edge, a coil spring can be inserted into this opening from the side, and is attached to the outer periphery of the inner yoke portion in a state where the opening is narrowed by bending the spring so that the opening faces the inner periphery and the spring is deformed into a circular or partial circular shape.

In this way, the coil spring can be inserted from the side into the spring hole of the spring housing portion before the spring housing portion is attached to the outer periphery of the inner yoke portion. This means that it is possible to use a parts feeder or other parts supply device to efficiently fit the coil spring into the spring hole without having to precisely target the position of the spring hole. Moreover, because the spring is rod-shaped before being bent, it requires less storage space and is easier to handle.

Furthermore, in the electromagnetic brake of the present invention, based on the above premise, a drop-out prevention portion is provided near the bottom of the spring hole to prevent the coil spring from dropping out.

This effectively prevents the coil spring from falling out of the bottom of the spring accommodating section before the spring accommodating section is attached to the outer periphery of the inner yoke section, even if the spring hole is open.

Furthermore, in the electromagnetic brake of the present invention, based on the above premise, the yoke is characterized in that it comprises an inner yoke portion having a coil on its outer periphery, and a spring accommodating portion separate from the inner yoke portion, the spring accommodating portion having a spring hole located on the outer periphery of the inner yoke portion including the coil .

A specific embodiment is one in which an outer yoke portion is provided on the outer periphery of the spring accommodating portion, and the spring accommodating portion is inserted axially into an annular gap formed between the inner yoke portion and the outer yoke portion.
In this way, the spring accommodating portion can be attached to the yoke body, which is made up of the inner yoke portion and the outer yoke portion, simply by inserting the spring accommodating portion into the annular gap from the axial direction.

Furthermore, the electromagnetic brake of the present invention is characterized in that, under the above-mentioned premise, an outer yoke portion that is separate from the inner yoke portion is provided on the outer periphery of the spring accommodating portion, the spring accommodating portion is located on the outer periphery of the inner yoke portion, and the outer yoke portion is fitted onto the outer periphery of the spring accommodating portion.

In this way, the spring accommodating portion can be fitted or wound around the outer periphery of the inner yoke portion, and then the outer yoke portion can be fitted around the outer periphery of the spring accommodating portion to complete the attachment of the spring accommodating portion to the yoke body, which is made up of the inner yoke portion and the outer yoke portion. Of course, it is also possible to first fit the outer yoke portion around the outer periphery of the inner yoke portion, and then insert the spring accommodating portion between the inner and outer yoke portions.

Furthermore, in the electromagnetic brake of the present invention, on the above premise, an intermediate wall forming part of the yoke is provided on the outer periphery of the inner yoke portion, and the spring accommodating portion is attached to the outer periphery of the intermediate wall.

In this way, the intermediate wall, together with the inner yoke portion, forms the yoke body, and also contributes to the stable installation of the spring accommodating portion.

In the above, it is preferable that the spring accommodating portion is made of a resin material.

This makes it easier to fit the spring housing into the core material, and also contributes to reducing the weight of the yoke.

The present invention as described above provides an electromagnetic brake with a structure suitable for automating the coil spring insertion process.

1 is a cross-sectional view showing an electromagnetic brake according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a yoke portion that constitutes the electromagnetic brake of FIG. 1 . FIG. 3 is a diagram showing the yoke portion of FIG. 2 in a state before assembly; FIG. 4 is an explanatory diagram of a spring accommodating portion used in the embodiment. FIG. 5 is an enlarged view of a portion of FIG. 4(b). FIG. FIG. FIG. 10 is a diagram showing another modified example of the present invention. FIG. 10 is a diagram showing yet another modified example of the present invention. FIG. 10 is a diagram showing another modified example of the present invention. FIG. 10 is a diagram showing the structure of a conventional spring housing portion.

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

This electromagnetic brake is essentially the same as the one shown in Figure 8 of the patent document. That is, as shown in Figure 1, it comprises a yoke 1, a coil 2 attached to the yoke 1, and a coil spring 10 attached to the yoke 1. The excitation force of the coil 2 and the spring force of the coil spring 10 allow the armature 4 to move axially. When de-energized, the coil spring 10 moves the armature 4, sandwiching a disk 5 between the armature 4 and the side plate 7, transmitting a braking force to the motor shaft 11 through the frictional force and holding force of the disk 5. When energized, electromagnetic force separates the armature 4 from the side plate 7, releasing the motor shaft 11 through the disk 5. The right half of Figure 1 is a cross-section of the electromagnetic brake taken along a line passing through the coil spring 10, and the left half is a cross-section of the electromagnetic brake taken along a line passing through the screw 9, described below, used in assembling the electromagnetic brake.

Specifically, the yoke 1 is fixed to the stationary frame 3 of the motor to which the electromagnetic brake is attached. The yoke 1 houses the current-carrying coil 2, and forms a magnetic path Φ between the yoke 1 and the armature 4, which is positioned axially on the motor shaft 11. A disk 5 is adjacent to the armature 4, and the disk 5 is fitted with a hub 6, restricting its rotational direction and allowing it to slide axially. The side plate 7 is fixed to the yoke 1 via a collar 8 with screws 9 or the like. Multiple coil springs 10 are housed in the yoke 1. The hub 6 is restricted in its rotational direction to the motor shaft 11 with a key 13 and is fixed via a retaining ring 12 or the like. Alternatively, the hub 6 may be fixed to the motor shaft 11 by press-fitting or adhesive. A predetermined gap is provided between the side plate 7 and the yoke 1 due to the dimensions of the collar 8, allowing the armature 4 and disk 5 to move axially within this gap. When the coil 2 is de-energized, the pressing force of the multiple coil springs 10 housed in the yoke 1 presses the disc 5 against the side plate 7 via the armature 4, and the disc 5 generates torque due to the frictional force at the contact surface between the armature 4 and the side plate 7, putting the brake into effect. When the coil 2 is energized, a magnetic path Φ is formed between the yoke 1 and the armature 4, generating a magnetic attraction force that overcomes the pressing force of the coil springs 10 and attracts the armature 4 to the yoke 1, releasing the disc 5 and disengaging the brake.

In this embodiment of the electromagnetic brake, as shown in the yoke assembly diagram of Figure 2 and the partial exploded view of the yoke in Figure 3, the portion of the yoke 1 structure that houses the coil spring 10 is separated from the yoke body 100 as the spring housing portion 103, thereby improving ease of installation of the coil spring 10.

Specifically, this electromagnetic brake has a yoke 1 that includes at least an inner yoke portion 101 and a spring accommodating portion 103 located on the outer periphery of the inner yoke portion 101 and having a spring hole 131. The spring accommodating portion 103 can be attached to the outer periphery of the inner yoke portion 101 with a coil spring 10 housed in the spring hole 131.

The yoke body 100, which forms the main body of the yoke 1, is constructed using an iron core material so that the inner yoke portion 101 and the outer yoke portion 102 are integral with each other, and has an annular gap 100a (a bottomed groove in this embodiment) on its upper surface. The coil 2 held by the coil holding member 2a is attached to the inner periphery of the annular gap 100a, and the spring housing portion 103 is inserted from above (axially) between the coil 2 and the outer yoke portion 102, as shown in Figure 2. Of course, the coil may be of a type that does not have a "coil holding member 2a," i.e., an "air-core coil type."

The spring accommodating portion 103 is made of a resin part, and normally, when the yoke 1 in FIG. 1 is viewed from the axial direction, the spring accommodating portion corresponds to the annular region as shown in FIG. 4(a). Line A-A in FIG. 4(a) indicates that FIG. 1 is a cross section taken along that line. The spring accommodating portion 103 in this embodiment has a shape similar to that obtained by cutting out this annular region. Furthermore, when deployed, the spring accommodating portion 103 is configured to have an elongated rod-like shape as shown in FIG. 4(b).

This spring accommodating section 103 has a spring hole 131 opening on one side edge, corresponding to the position of the spring hole 1x in Figure 4(a), and the coil spring 10 can be inserted into this opening from the side. The spring accommodating section 103 is then bent so that the opening of the spring hole 131 faces inward, as shown in Figures 4(c), 5(a), and (b), thereby narrowing the opening and deforming it into an annular shape, allowing it to be inserted from above (axially) into the annular gap 100a in the yoke body 100, as shown in Figure 3. In the unfolded state shown in Figure 4(b), the spring hole 131 has a U-shaped groove shape.

In addition, V-shaped notches 132 are provided between the spring holes 131, 131 to make it easier to bend the spring accommodating section 103. In other words, the spring accommodating section 103 is made up of a number of separate spring accommodating sections (sections in which the spring holes 131 are formed), and these spring accommodating sections are connected by thin-walled groove bottoms of the notches 132.

Therefore, with the spring accommodating portion 103 in the expanded state shown in Figure 4(b), the coil spring 10 is inserted from the side (i.e., in a direction approximately perpendicular to the axial direction of the coil spring 10 accommodated in the spring hole 131) into the spring hole 131 opening on one side edge, and then the spring accommodating portion 103 is bent into an annular shape as shown in Figures 4(c) and 5(a)-(b). Then, as shown in Figure 3, this spring accommodating portion 103 is inserted from above into the annular gap 100a in the yoke body 100, thereby completing the attachment of the coil spring 10 to the yoke body 100.

The spring accommodating portion 103 also has an escape hole 133 for the fixing screw 9 used during brake assembly as shown in Figure 1 (see Figures 4 and 5). This escape hole 133 is also provided in a position corresponding to the spring insertion groove 1y in Figure 4(a), and by providing an opening on the inner periphery, it can accommodate bending deformation toward the inner periphery.

The collar 8 in Figure 1 has a portion in contact with the yoke 1 (the portion indicated by P in the figure), which reduces the force applied to the spring accommodating portion 103 when the screw is tightened.

As described above, the electromagnetic brake of this embodiment comprises a yoke 1, a coil 2 attached to the yoke 1, and a coil spring 10 attached to the yoke 1. The ON/OFF state of the brake is switched by the excitation force of the coil 2 and the spring force of the coil spring 10. The yoke 1 comprises an inner yoke portion 101 and a spring accommodating portion 103 located on the outer periphery of the inner yoke portion 101 and having a spring hole 131. The spring accommodating portion 103 can be attached to the outer periphery of the inner yoke portion 101 with the coil spring 10 housed in the spring hole 131.

In the conventional structure shown in Figure 11, the spring accommodating portion 103 is an integral part of the yoke 1. In contrast, in this embodiment, the spring accommodating portion 103 is separated from the yoke 1, allowing the coil spring 10 to be accommodated in the spring hole 131 of the spring accommodating portion 103 before the spring accommodating portion 103 is positioned on the outer periphery of the inner yoke portion 101. Therefore, by designing the spring accommodating portion 103 to facilitate insertion of the coil spring 10, the conventional problem shown in Figure 11 can be eliminated, namely, the robotic process of setting and locating the spring hole position, and then inserting the coil spring by aiming at the spring hole opening from the direction of its opening. This reduces the work time. Naturally, similar effects can be achieved when the work is performed manually.

The spring accommodating portion 103 has an elongated rod-like shape, with a spring hole 131 opening on one side edge, into which the coil spring 10 can be inserted from the side. The opening is then bent so that it faces the inner periphery, narrowing the opening and deforming it into a circular shape, allowing it to be attached to the outer periphery of the inner yoke portion 101.

This allows the coil spring 10 to be inserted into the spring hole 131 of the spring accommodating portion 103 before attaching the spring accommodating portion 103 to the outer periphery of the inner yoke portion 101. This eliminates the need to precisely target the position of the spring hole 131, and makes it possible to use a parts supply device such as a parts feeder to efficiently place the coil spring into the spring hole. Furthermore, by making the spring accommodating portion 103 rod-shaped, there is no dead space on the inner periphery compared to when it is constructed to be annular from the start, so less storage space is required and it is convenient for transportation and for constructing a coil spring loading device.

In addition, an outer yoke portion 102 is provided around the outer periphery of the spring accommodating portion 103, and the spring accommodating portion 103 is configured to be inserted axially into the annular gap 100a formed between the inner yoke portion 101 and the outer yoke portion 102.

As a result, simply by inserting the spring accommodating portion 103 axially into the annular gap 100a, the spring accommodating portion 103 can be attached to the yoke body 100, which is made up of the inner yoke portion 101 and the outer yoke portion 102.

In addition, the spring accommodating portion 103 in this embodiment is made of a resin material. This makes it easier to fit the spring accommodating portion 103 into the yoke body 100, which is made of iron core material, and having a portion of the yoke 1 made of resin also contributes to reducing the overall weight of the yoke 1.

Although one embodiment of the present invention has been described above, the specific configuration of each part is not limited to the above-described embodiment.

For example, as shown in Figure 6, a fall prevention portion 131a that prevents the coil spring 10 from falling off may be provided near the bottom of the spring hole 131.

In this way, even if the spring hole 131 penetrates in the vertical direction, it is possible to effectively prevent the coil spring 10 from falling out of the bottom of the spring accommodating portion 103 during movement when positioning the spring accommodating portion 103 at the outer periphery of the inner yoke portion 101.

It is also effective to provide a recess 133a and a protrusion 133b in the fixing screw relief hole 133, as shown in Figure 7. These recesses 133a and protrusions 133b are provided on both sides of the opening edge of the fixing screw relief hole 133, so that when the fixing screw relief hole 133 is bent, one recess 133a fits into the other protrusion 133b, allowing the fixing screw relief hole 133 to close in a desirable shape. By using such a shape, for example, the gap in the cutout of the relief hole 133 for the fixing screw 9 in Figure 5(b) is eliminated. This allows the screw to press evenly around the periphery of the relief hole 133 when tightening the screw, and also reduces deformation of the spring accommodating portion 103 due to the screw tightening force. This configuration is effective when the spring accommodating portion 103 is made of a soft material such as resin.

Also, as shown in Figure 8, a structure can be used in which an outer yoke portion 102 separate from the inner yoke portion 101 is provided around the outer periphery of the spring accommodating portion 103, with the spring accommodating portion 103 positioned around the outer periphery of the inner yoke portion 101 and the outer yoke portion 102 fitted around the outer periphery of the spring accommodating portion 103.

In this way, after fitting or winding the spring accommodating portion 103 around the outer periphery of the inner yoke portion 101, the outer yoke portion 102 can be fitted around the outer periphery of the spring accommodating portion 103 to complete the attachment of the spring accommodating portion 103 to the yoke body 100, which is made up of the inner yoke portion 101 and the outer yoke portion 102. Of course, it is also possible to insert the spring accommodating portion 103 between the inner yoke portion 101 and the outer yoke portion 102 after fitting the outer yoke portion 102 into the inner yoke portion 101.

Alternatively, as shown in Figure 9(a), an intermediate wall 104 forming part of the yoke 1 may be provided on the outer periphery of the inner yoke portion 101, and the spring accommodating portion 103 may be attached to the outer periphery of the intermediate wall 104.

In this way, the intermediate wall 104, together with the inner yoke portion 101, constitutes the yoke body 100 and also contributes to the stable installation of the spring accommodating portion 103. In this case, the spring accommodating portion 103 can be fixed by fitting the outer yoke portion 102 to the outside of the spring accommodating portion 103. In this case, the outer yoke portion 102 does not necessarily have to be made of an iron core material, as the intermediate wall 104 forms a magnetic path.

In addition, in the structure shown in Figure 9(a), the intermediate wall 104 is configured integrally with the inner yoke portion 101, but it may also be attached as a separate body from the inner yoke portion 101, as in the intermediate wall 104' shown in Figure 9(b).

Alternatively, as shown in Figure 10(a), if the spring accommodating portion 103 can be stably attached, the outer yoke portion can be omitted.

Also, as shown in Figure 10(b), a spacer 8 that keeps the distance between the side plate 7 and the yoke 1 constant may be integrally formed in the part of the spring accommodating section 103 where the fixing screw relief hole 133 used during brake assembly is provided. This allows for a reduction in the number of parts.

Furthermore, the spring accommodating portion does not necessarily have to be circular; it can also be configured as a partial ring, with two or more portions assembled to form a ring.

Alternatively, the spring accommodating section may be configured in a continuous, long form, for example wound up like a reel, and then cut to the required length for use.

Furthermore, if convenience in storage, etc. is not required, there is nothing to prevent the spring accommodating portion from being molded into a circular shape from the beginning.

Various modifications to other configurations are possible without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1... yoke 2... coil 10... coil spring 100a... annular gap 101... inner yoke portion 102... outer yoke portion 103... spring accommodating portion 104... intermediate wall 131... spring hole 131a... fall-off prevention portion

Claims (6)

A brake device comprising a yoke, a coil provided in the yoke, and a coil spring provided in the yoke, in which the ON/OFF state of a brake is switched by the excitation force of the coil and the spring force of the coil spring,
The yoke comprises an inner yoke portion and a spring accommodating portion located on the outer periphery of the inner yoke portion and having a spring hole, and the spring accommodating portion can be attached to the outer periphery of the inner yoke portion with a coil spring accommodated in the spring hole,
the spring accommodating portion has an elongated rod-like shape, a spring hole opening at one side edge, a coil spring can be inserted into this opening from the side, and the spring accommodating portion is attached to the outer periphery of the inner yoke portion in a state where the opening is narrowed by bending the spring accommodating portion so that the opening faces the inner periphery and the spring is deformed into a circular or partial circular shape. A brake device comprising a yoke, a coil provided in the yoke, and a coil spring provided in the yoke, in which the ON/OFF state of a brake is switched by the excitation force of the coil and the spring force of the coil spring,
The yoke comprises an inner yoke portion and a spring accommodating portion located on the outer periphery of the inner yoke portion and having a spring hole, and the spring accommodating portion can be attached to the outer periphery of the inner yoke portion with a coil spring accommodated in the spring hole,
An electromagnetic brake characterized in that a fall-off prevention portion is provided near the bottom of the spring hole to prevent the coil spring from falling off. A brake device comprising a yoke, a coil provided in the yoke, and a coil spring provided in the yoke, in which the ON/OFF state of a brake is switched by the excitation force of the coil and the spring force of the coil spring,
an electromagnetic brake, characterized in that the yoke comprises an inner yoke portion having a coil provided on its outer periphery, and a spring accommodating portion separate from the inner yoke portion, the spring accommodating portion having a spring hole located on the outer periphery of the inner yoke portion including the coil, and the spring accommodating portion can be attached to the outer periphery of the inner yoke portion with a coil spring accommodated in the spring hole. 4. The electromagnetic brake according to claim 3, further comprising an outer yoke portion on an outer periphery of the spring accommodating portion, the spring accommodating portion being inserted in the axial direction into an annular gap formed between the inner yoke portion and the outer yoke portion. A brake device comprising a yoke, a coil provided in the yoke, and a coil spring provided in the yoke, in which the ON/OFF state of a brake is switched by the excitation force of the coil and the spring force of the coil spring,
The yoke comprises an inner yoke portion and a spring accommodating portion located on the outer periphery of the inner yoke portion and having a spring hole, and the spring accommodating portion can be attached to the outer periphery of the inner yoke portion with a coil spring accommodated in the spring hole,
An electromagnetic brake characterized in that the electromagnetic brake has a structure in which an outer yoke portion separate from the inner yoke portion is provided on the outer periphery of the spring accommodating portion, the spring accommodating portion is located on the outer periphery of the inner yoke portion, and the outer yoke portion is fitted onto the outer periphery of the spring accommodating portion. A brake device comprising a yoke, a coil provided in the yoke, and a coil spring provided in the yoke, in which the ON/OFF state of a brake is switched by the excitation force of the coil and the spring force of the coil spring,
The yoke comprises an inner yoke portion and a spring accommodating portion located on the outer periphery of the inner yoke portion and having a spring hole, and the spring accommodating portion can be attached to the outer periphery of the inner yoke portion with a coil spring accommodated in the spring hole,
An electromagnetic brake comprising an intermediate wall forming a part of the yoke at an outer periphery of the inner yoke portion, and the spring accommodating portion attached to an outer periphery of the intermediate wall.