Electromagnetic brake device

Abstract

To provide a light-weight non-excitation operative brake.SOLUTION: An electromagnetic brake device 3 includes a yoke 30, a guide pin 26, an outer plate 24, and an inner plate 25. On the end face of the yoke 30, a plurality of pin mounting holes 38 are provided in the peripheral direction. An outer peripheral wall part 32 of the yoke 30 has thick parts 32y in each of which the pin mounting hole 38 is provided, and thin parts 32x provided between the thick parts 32y. The outer peripheral face of each thin part 32x is recessed radially inside of a virtual circle O.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electromagnetic brake device. [Background technology]

[0002] Patent Document 1 discloses a motor with a built-in brake, which has an electromagnetic brake device that applies a braking force to the motor when it is not energized. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-372078 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, however, there has been a demand for reducing the weight of electromagnetic brake devices such as that described in Patent Document 1. Therefore, an object of the present disclosure is to provide a lightweight electromagnetic brake device. [Means for solving the problem]

[0005] An electromagnetic brake device according to one aspect of the present invention comprises: a yoke for housing the winding; A guide pin provided on an end surface of the yoke; an outer plate fixed at a position spaced apart from the yoke by the guide pin; an inner plate provided between an end surface of the yoke and the outer plate, The inner plate is fixed by the guide pin so as to be movable in the direction of the rotation axis but not rotatable, A plurality of pin mounting holes into which the guide pins are mounted are provided in a circumferential direction on an end surface of the yoke, the outer peripheral wall portion of the yoke has a plurality of thick portions in which the pin mounting holes are respectively provided, and thin portions provided between the plurality of thick portions in the circumferential direction, The outer peripheral surface of the thin portion is recessed radially inward from an imaginary circle centered on the rotation axis, the imaginary circle being formed by connecting points of the pin mounting hole farthest from the rotation axis. Effect of the Invention

[0006] According to the present disclosure, a lightweight electromagnetic brake device is provided. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view of a motor having an electromagnetic brake device according to the present disclosure. [Diagram 2] FIG. 2 is an enlarged partial view of FIG. 1 showing the brake mechanism. [Diagram 3] FIG. 3 is a front view of the yoke. [Figure 4] FIG. 4 is a front view of a yoke of an electromagnetic brake device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. For the sake of convenience, the description of the members having the same reference numbers as those already described in the description of the embodiment will be omitted.

[0009] Fig. 1 is a cross-sectional view of a motor with a built-in brake 1 having an electromagnetic brake device 3 according to the present disclosure. As shown in Fig. 1, the motor with a built-in brake 1 has a motor 2, an electromagnetic brake device 3, and a case 4 that covers the motor 2 and the electromagnetic brake device 3. The motor with a built-in brake 1 according to the present disclosure is a motor with a built-in brake equipped with an electromagnetic brake device, in which a braking force acts on the motor 2 when not energized.

[0010] The electromagnetic brake device 3 has a rotating shaft portion 10 extending in the direction of the rotation axis Ax, a brake mechanism 20 that applies a braking force to the rotating shaft portion 10, and a bearing 5 that supports the brake mechanism 20 rotatably relative to the rotating shaft portion 10. In the following description, with respect to the direction of the rotation axis Ax, the left side in Fig. 1 may be referred to as the front F, and the right side in Fig. 1 may be referred to as the rear R.

[0011] In Fig. 1, the electromagnetic brake device 3 is provided behind the motor 2. The rotating shaft portion 10 is connected to the output shaft 2a of the motor 2. The rotating shaft portion 10 rotates around the rotation axis Ax together with the motor 2. The rotating shaft portion 10 may be integral with the output shaft 2a of the motor 2, or may be a separate member from the output shaft 2a of the motor 2. The rotating shaft portion 10 may be connected to the output shaft 2a of the motor 2 by a power transmission member such as a gear.

[0012] The brake mechanism 20 includes a winding 21 , a yoke 30 that houses the winding 21 , and a spring 22 . The winding 21 is disposed within the yoke 30 and is a metal wire, such as a copper wire, wound to form a coil. The winding 21 is wound to form a coil having a substantially cylindrical shape as a whole.

[0013] The yoke 30 is a metal member having an accommodation portion 37 for accommodating the winding 21 therein. The yoke 30 is a cylindrical member with a bottom. The yoke 30 integrally includes an inner circumferential wall portion 31 that covers the inner periphery of the cylindrical winding 21, an outer circumferential wall portion 32 that covers the outer periphery of the cylindrical winding 21, and an end wall portion 33 that covers the end of the cylindrical winding 21 on the opposite side to the motor 2 with respect to the rotation axis Ax.

[0014] The rotating shaft portion 10 passes through a through hole 34 on the inner peripheral side of the inner peripheral wall portion 31. The rotating shaft portion 10 is rotatably supported with respect to the yoke 30 via a bearing 5 provided in the yoke 30.

[0015] The internal space formed by the inner circumferential wall portion 31, the outer circumferential wall portion 32, and the end wall portion 33 is the accommodation portion 37. The accommodation portion 37 opens forward (toward the motor 2) in the direction of the rotation axis Ax. When a current is applied to the winding 21, the yoke 30 forms a magnetic circuit of magnetic lines of force generated in the winding 21. The yoke 30 increases the magnetic flux density of the magnetic force, thereby increasing the magnetic force.

[0016] Fig. 2 is a partially enlarged view of Fig. 1 showing the brake mechanism 20. As shown in Fig. 2, the brake mechanism 20 further has a friction member 23, an outer plate 24, an inner plate 25, and a guide pin 26. The outer plate 24, the friction member 23, and the inner plate 25 are arranged in this order from front to rear in the direction of the rotation axis Ax.

[0017] The guide pin 26 has a pin 26a extending in the direction of the rotation axis Ax and a sleeve 26b through which the pin 26a is inserted. A head 26c of the guide pin 26 protrudes forward from a front end face of the yoke 30. A rear end of the guide pin 26 located opposite the head 26c is fixed to the yoke 30. The guide pin 26 is fixed to an outer circumferential wall portion 32 located radially outward of the housing portion 37 of the yoke 30. The multiple guide pins 26 are provided along the circumferential direction on a front end face 32a of the outer circumferential wall portion 32 of the yoke 30.

[0018] The pin 26a is inserted through a sleeve 26b. A head 26c of the guide pin 26 is fixed via the sleeve 26b at a position spaced apart from a front end surface 30a of the yoke 30. The guide pin 26 is fixed to the yoke 30 by a fixing means such as adhesion, welding, press-fitting, fitting, or screwing.

[0019] The outer plate 24 is a plate-like member extending in a radial direction intersecting with the rotation axis Ax. The outer plate 24 is also ring-shaped, and the rotation shaft portion 10 passes through a through hole provided in the radial center of the outer plate 24. The outer plate 24 is fixed by being sandwiched between a head 26c of a guide pin 26 and a sleeve 26b. The outer plate 24 is fixed at a position separated from a front end surface 30a of the yoke 30 via the sleeve 26b. In other words, the outer plate 24 is immovable relative to the yoke 30.

[0020] The friction member 23 is a plate-like member extending in a radial direction intersecting with the rotation axis Ax. The friction member 23 is also ring-shaped, and the rotating shaft portion 10 passes through a through hole provided in the radial center of the friction member 23. The friction member 23 is a member having a surface with a high friction coefficient that generates a friction force between the friction member 23 and the outer plate 24. The friction member 23 can be composed of, for example, a metal main body and a high-friction material made of ceramics or the like attached to the surface of the main body.

[0021] The outer circumferential surface of the friction member 23 is located radially inward of the sleeve 26b of the guide pin 26. The friction member 23 is located between the sleeve 26b and the rotating shaft portion 10 in the radial direction.

[0022] An engagement groove 23a extending in the direction of the rotation axis Ax is provided on the inner peripheral surface of the friction member 23. This engagement groove 23a has a shape corresponding to an engagement portion 27a provided on the outer peripheral surface of a hub member 27 fixed to the rotating shaft portion 10. Therefore, the friction member 23 is movable in the direction of the rotation axis Ax relative to the rotating shaft portion 10 but cannot rotate around the rotation axis Ax. In other words, the friction member 23 rotates in conjunction with the rotation of the rotating shaft portion 10.

[0023] The inner plate 25 is a plate-like member extending in a radial direction intersecting with the rotation axis Ax. The inner plate 25 is also ring-shaped, and the rotation shaft portion 10 passes through an inner peripheral hole of the inner plate 25. The outer peripheral portion of the inner plate 25 is provided with recesses having a shape corresponding to the sleeves 26b of the guide pins 26. In other words, the inner plate 25 is prevented from rotating around the rotation axis Ax by the sleeves 26b. For this reason, like the friction member 23, the inner plate 25 is movable in the direction of the rotation axis Ax but is unable to rotate around the rotation axis Ax.

[0024] Returning to FIG. 1 , the spring 22 is accommodated in a spring accommodating portion 35 that opens on the front end surface of the yoke 30. The spring 22 is, for example, a coil spring. The spring 22 is accommodated in the spring accommodating portion 35 in a compressed state. The spring 22 exerts an elastic restoring force on the inner plate 25, which presses the inner plate 25 against the friction member 23.

[0025] As shown in Fig. 2, the bearing 5 supports the yoke 30 of the brake mechanism 20 rotatably around the rotation axis Ax with respect to the rotating shaft portion 10. The bearing 5 has an inner ring 51, an outer ring 52, and rolling elements 53. The inner ring 51 is fixed to the rotating shaft portion 10. The outer ring 52 is fixed to the yoke 30. The yoke 30 has a bearing fixing portion 36 to which the outer ring 52 of the bearing 5 is fixed. In the illustrated example, the bearing fixing portion 36 is provided at the rear end portion of the inner circumferential wall portion 31 of the yoke 30. The motor-side bearing, which is located on the front side in the direction of the rotation axis Ax, supports the output shaft 2a of the motor 2 rotatably relative to the case 4.

[0026] In the motor with built-in brake 1, in the normal state when the motor 2 is operating, power is also supplied to the windings 21. When current is applied to the windings 21, electromagnetic force is generated by the windings 21. This electromagnetic force attracts the inner plate 25 to the yoke 30 against the elastic restoring force of the spring 22. In this state, gaps are generated between the inner plate 25 and the friction member 23, and between the friction member 23 and the outer plate 24, and no frictional force is generated between the respective members. In other words, in the normal state of the motor with built-in brake 1, no braking force is generated by the brake mechanism 20.

[0027] In a non-energized state in which the current to the windings 21 is cut off, such as when the current to the motor 2 is interrupted, no electromagnetic force acts on the windings 21. Therefore, the elastic restoring force of the springs 22 causes the inner plate 25 to press the friction member 23 against the outer plate 24. Therefore, frictional forces are generated between the inner plate 25 and the friction member 23, and between the friction member 23 and the outer plate 24. That is, in a non-energized state, a braking force is generated by the brake mechanism 20.

[0028] 3 is a view of the yoke 30 as viewed from the front. As shown in FIG. 3, when the yoke 30 is viewed from the front, a through hole 34 through which the rotating shaft 10 is inserted, an inner circumferential wall 31, a housing 37, and an outer circumferential wall 32 are provided in the radial center from the radial inside to the radial outside. In the illustrated example, a spring housing 35 is provided in the inner circumferential wall 31, and a pin mounting hole 38 into which the guide pin 26 is mounted is provided in the outer circumferential wall 32. Six spring housings 35 are provided at equal intervals along the circumferential direction on the inner circumferential wall 31. The thickness (radial dimension) of the inner circumferential wall 31 is constant along the circumferential direction.

[0029] The thickness (diameter dimension) of the outer peripheral wall portion 32 is not constant along the circumferential direction. The outer peripheral wall portion 32 has a plurality of thin portions 32x and a plurality of thick portions 32y that are provided between adjacent thin portions 32x and have a greater thickness than the thin portions 32x. In the illustrated example, the outer peripheral wall portion 32 has three thin portions 32x and three thick portions 32y. Two pin mounting holes 38 are provided in one thick portion 32y. The two pin mounting holes 38 are arranged in the circumferential direction. The pin mounting holes 38 are not provided at equal intervals in the circumferential direction. The interval R1 between adjacent pin mounting holes 38 provided in the thick portion 32y is shorter than the interval R2 between the pin mounting holes 38 separated by the thin portion 32x.

[0030] 3 shows an imaginary circle O centered on the rotation axis Ax, which is formed by connecting the points of the pin mounting hole 38 farthest from the rotation axis Ax. The outer peripheral surface 32z of the thin-walled portion 32x is located inside this imaginary circle O. In the example shown, the distance from the rotation axis Ax to the outer peripheral surface of the thin-walled portion 32x is equal to the distance from the rotation axis Ax to the central axis of the pin mounting hole 38. In contrast, the outer peripheral surface 32z of the thick-walled portion 32y is located outside this imaginary circle O. Thus, according to the electromagnetic brake device 3 (electromagnetic brake device) of the present disclosure, the outer peripheral surface 32z of the thin-walled portion 32x is recessed radially inward from an imaginary circle O centered on the rotation axis Ax, which is formed by connecting the points furthest from the rotation axis Ax of the pin mounting hole 38.

[0031] The yoke 30 is made of cast iron or the like, and is a relatively heavy metallic member. When considering ways to reduce the weight of the electromagnetic brake device 3, the present inventors focused on this heavy yoke 30. The yoke 30 of the electromagnetic brake device 3 of the present disclosure has a first function of increasing the magnetic force generated in the winding 21 and a second function of supporting the guide pin 26. Regarding the first function, the inner circumferential wall portion 31 is required to have a certain thickness in order to increase the magnetic flux density generated in the winding 21, but the outer circumferential wall portion 32 is not required to have such a thickness. Therefore, the inventors have considered reducing the weight of the yoke 30 by reducing the thickness of the outer circumferential wall portion 32. Regarding the second function, reducing the thickness may impair the function of supporting the guide pin 26, but they have focused on the fact that the outer circumferential wall portion 32 has a portion where the guide pin 26 is not provided. Thus, the inventors came up with the idea of ​​reducing the thickness of the portion of the outer circumferential wall portion 32 where the guide pin 26 is not provided, and completed the present invention. According to the electromagnetic brake device 3 of the present disclosure, the mounting strength of the guide pin 26 is ensured by the thick-walled portion 32y of the outer peripheral wall portion 32 of the yoke 30, while the thickness of the thin-walled portion 32x where the pin mounting hole 38 is not provided is reduced, thereby making it possible to reduce the weight of the yoke 30.

[0032] In addition, in the electromagnetic brake device 3 of the present disclosure, a single thick-walled portion 32y is provided with a plurality of pin mounting holes 38. Since the plurality of pin mounting holes 38 are provided intensively in the single thick-walled portion 32y, it is easier to reduce the number of thick-walled portions 32y compared to a case in which a single pin mounting hole 38 is provided in a single thick-walled portion 32y. This makes it easier to reduce the weight of the yoke 30 by using the thin-walled portions 32x.

[0033] Fig. 4 is a front view of a yoke 30A of an electromagnetic brake device 3 according to a modified example of the present disclosure. In the example shown in Fig. 4, the outer peripheral wall of the yoke 30A has four thick portions 32y and four thin portions 32x. In this example, two pin mounting holes 38 are provided in one thick portion 32y, and the yoke 30A has eight pin mounting holes 38. In this example, the outer peripheral surface 32z of the thin-walled portion 32x is also recessed radially inward from an imaginary circle O that is centered on the rotation axis Ax and is formed by connecting the points furthest from the rotation axis Ax of the pin mounting hole 38. This reduces the weight of the yoke 30, thereby providing a lightweight electromagnetic brake device 3.

[0034] Although the embodiment of the present disclosure has been described above, it goes without saying that the technical scope of the present disclosure should not be interpreted as being limited by the description of the present embodiment. The present embodiment is merely an example, and it is understood by those skilled in the art that various modifications of the embodiment are possible within the scope of the invention described in the claims. The technical scope of the present disclosure should be determined based on the scope of the invention described in the claims and its equivalents.

[0035] In the above description, the spring accommodating portion 35 is provided in the inner circumferential wall portion 31, but the spring accommodating portion 35 may be provided in the outer circumferential wall portion 32. When the spring accommodating portion 35 is provided in the outer circumferential wall portion 32, it is preferable that the spring accommodating portion 35 is also provided in the thick portion 32y.

[0036] In the above description, the friction member 23 is described as a member having a high friction material, but the present disclosure is not limited to this. The friction member 23 may not have a high friction material, and a high friction material may be attached to a portion of the outer plate 24 or the inner plate 25 that comes into contact with the friction member 23. It is sufficient that the friction member 23 is configured to come into contact with at least one of the outer plate 24 and the inner plate 25 to generate a frictional force. [Explanation of symbols]

[0037] 1 Motor with built-in brake 2 Motors 2a Output shaft 3. Electromagnetic brake device 4 Cases 5. Bearings 10 Rotating shaft 20 Brake mechanism 21 Windings 22 Spring 23 Friction materials 23a Fitting groove 24 Outer plate 25 Inner plate 26 Guide pin 26a Pin 26b Sleeve 26c head 27 Hub parts 30 York 30a Front end face of yoke 31 Inner peripheral wall 32 Outer wall 32a Front end face of outer wall 32x thin section 32y thick part 32z Thin-walled outer surface 33 End wall 33a Inner surface of end wall 34 Through hole 35 Spring housing 36 Bearing fixing part 37 Storage unit 51 Inner Circle 52 Outer ring 53 Rolling elements 55 Motor side bearing Ax Rotation axis O Virtual circle

Claims

1. a yoke for housing the winding; A guide pin provided on an end surface of the yoke; an outer plate fixed at a position spaced apart from the yoke by the guide pin; an inner plate provided between an end surface of the yoke and the outer plate, The inner plate is fixed by the guide pin so as to be movable in the direction of the rotation axis but not rotatable, A plurality of pin mounting holes into which the guide pins are mounted are provided in a circumferential direction on an end surface of the yoke, the outer peripheral wall portion of the yoke has a plurality of thick portions in which the pin mounting holes are respectively provided, and thin portions provided between the plurality of thick portions in the circumferential direction, an outer peripheral surface of the thin-walled portion is recessed radially inward from an imaginary circle centered on the rotation axis, the imaginary circle being formed by connecting points of the pin mounting hole farthest from the rotation axis.

2. 2. The electromagnetic brake device according to claim 1, wherein the guide pin is bonded, welded, press-fitted, fitted, or screwed to the yoke.

3. 2. The electromagnetic brake device according to claim 1, wherein a plurality of said pin mounting holes are provided in a single said thick-walled portion.

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