Braking device

Abstract

This suppresses noise generated when the disc rotates and improves the precision of stopping the rotation of the spindle. [Solution] The device comprises a disc fixed to a rotating shaft, a receiving portion provided facing one side of the disc, a movable portion provided facing the other side of the disc and movable in the direction approaching the disc and the direction away from the disc, and a drive unit that moves the movable portion in the direction approaching and the direction away from the disc. The disc is fixed to the rotating shaft so as not to be displaced in the direction around the axis and in the axial direction relative to the rotating shaft. Braking force is generated when the disc and the receiving portion come into contact and when the disc and the movable portion come into contact. The disc is elastically deformable in the direction along the rotating shaft. When not braking, a predetermined gap is provided between the disc and the receiving portion and between the disc and the movable portion. When braking, the drive unit moves the movable portion in the direction approaching, causing the movable portion to press against the disc, and the disc to elastically deform and press against the receiving portion.

Description

Technical Field

[0001] The present invention relates to a braking device.

Background Art

[0002] Conventionally, an electromagnetic brake device that operates by the electromagnetic force of an electromagnetic coil has been proposed, and an example thereof is disclosed in Patent Document 1. The electromagnetic brake device 1A (see FIG. 4) described in Patent Document 1 includes a field core (not shown) and a side plate 20A that form the frame of the electromagnetic brake device 1A, and an armature (not shown) disposed between the field core and the side plate 20A. Further, the electromagnetic brake device 1A includes a brake disk 60A disposed between the armature and the side plate 20A. The brake disk 60A is connected to a rotating shaft 70A of a motor or the like via a hub 80A. Further, the electromagnetic brake device 1A includes a compression coil spring 14A that biases the armature toward the brake disk side, and an electromagnetic coil (not shown) that generates a magnetic attractive force in a direction away from the brake disk with respect to the armature. The armature reciprocates in the axial direction of the rotating shaft 70A by the biasing force of the compression coil spring 14A and the magnetic attractive force of the electromagnetic coil. When the armature moves toward the brake disk side, the armature presses the brake disk, and the brake disk is sandwiched between the armature and the side plate 20A to perform braking by the brake device. Also, when the armature moves in a direction away from the brake disk, the brake disk separates from the armature, and the braking by the brake device is released.

[0003] A through-hole is formed in the radial center of the brake disc 60A into which the hub 80A is inserted. As shown in Figure 5, multiple internal teeth 61A (splines) are formed on the inner circumferential surface of this through-hole, which mesh with multiple external teeth 81A (splines) formed on the outer circumferential surface of the hub 80A. The internal teeth 61A of the brake disc 60A mesh with the external teeth 81A of the hub 80A so as to be slidable in the axial direction of the hub 80A (the axial direction of the rotation axis 70A). As the armature reciprocates in the axial direction of the rotation axis 70A, the internal teeth 61A of the brake disc 60A slide in the axial direction of the hub 80A relative to the external teeth 81A of the hub 80A. Also, as shown in Figure 5, a gap G (backlash) is provided between the internal teeth 61A of the brake disc 60A and the external teeth 81A of the hub 80A. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2016-56925 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In the electromagnetic brake device described in Patent Document 1, the brake disc 60A and the hub 80A are connected by the meshing of the internal teeth 61A of the brake disc 60A with the external teeth 81A of the hub 80A. As a result, there is a problem that vibration and noise are generated when the brake disc 60A rotates due to the meshing of the internal teeth 61A and the external teeth 81A. Furthermore, because a gap G (backlash) is provided between the internal teeth 61A and the external teeth 81A, there is a problem that the accuracy of stopping the rotation of the rotating shaft 70A relative to the brake disc 60A is reduced. In addition, when the internal teeth 61A of the brake disc 60A rotate while meshing with the external teeth 81A of the hub 80A, and when the internal teeth 61A of the brake disc 60A slide in the axial direction of the hub 80A relative to the external teeth 81A of the hub 80A, the contact surfaces wear down, which further reduces the accuracy of stopping the rotation of the rotating shaft 70A relative to the brake disc 60A. Furthermore, wear particles generated by abrasion on the contact surface may adhere to the spline, rust, and become stuck to the spline, potentially hindering the armature's reciprocating motion in the axial direction of the rotating shaft 70A.

[0006] In view of the above problems, the present invention aims to provide a braking device that can suppress noise when the brake disc rotates and improve the accuracy of stopping the rotation of the rotating shaft. [Means for solving the problem]

[0007] The braking device of the present invention is a braking device for braking the rotation of a rotating shaft to be braked, comprising: a disk fixed to the rotating shaft such that its central axis coincides with the axis of the rotating shaft; a receiving portion provided facing one side of the disk; a movable portion provided facing the other side of the disk and movable in an approaching direction toward the disk and a moving direction toward the disk; and a drive unit for moving the movable portion in the approaching direction and the moving direction, wherein the disk is fixed to the rotating shaft so as not to be displaced in the direction around the axis of the rotating shaft and in the axial direction, and the disk and the receiving portion The braking device is configured such that when the disc and the movable part come into contact, a braking force is generated by friction, and when the disc and the movable part come into contact, a braking force is generated by friction, the disc is elastically deformable in a direction along the axis of rotation, and when the braking device is not braking, a predetermined gap is provided between the disc and the receiving part and between the disc and the movable part, and when the braking device is braking, the drive unit moves the movable part in the approaching direction, causing the movable part to press the disc toward the receiving part, and the disc elastically deforms toward the receiving part, causing the disc to press against the receiving part. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a braking device that can suppress noise when a disk rotates and improve the precision of stopping the rotation of the disk. [Brief explanation of the drawing]

[0009] [Figure 1] This is a front view showing an example of a braking device according to one embodiment of the present invention. [Figure 2] Figure 1 is a cross-sectional view of the braking system along line AA, showing the braking system in a non-braking state. [Figure 3] Figure 1 is a cross-sectional view of the braking system along line A and B, showing the braking system during braking. [Figure 4]This is a front view showing an example of a conventional braking system. [Figure 5] This is a magnified view of a part of the braking system shown in Figure 4 (the area enclosed by the dashed line). [Modes for carrying out the invention]

[0010] A braking device according to one embodiment of the present invention will be described below with reference to the drawings. Note that the embodiments shown below are merely examples, and the braking device of the present invention is not limited to these embodiments.

[0011] The braking device 1 according to this embodiment (see Figures 1 to 3) is a device for braking the rotation of a rotating shaft R that is to be braked. The braking device 1 can be used, for example, as a device for braking the rotation of a rotating shaft in a machine having a rotating shaft (for example, a vehicle, a robot, etc.). In this specification, "braking" includes not only suppressing the rotation of a rotating shaft R (reducing the rotational speed or stopping the rotation), but also maintaining the non-rotating state of a rotating shaft R that is not rotating (stopped).

[0012] In this specification and in the drawings, direction D1 (see Figures 2 and 3) represents the direction along the axis of rotation R (hereinafter also referred to as axial direction D1), direction D11 represents the direction toward the tip of the axis of rotation R in the axial direction D1 (hereinafter also referred to as the tip direction D11 or tip-side D11), and direction D12 represents the direction toward the base end (or the center in the longitudinal direction) of the axis of rotation R in the axial direction D1 (hereinafter also referred to as the base end direction D12 or base-side D12). Furthermore, direction D2 (see Figure 1) represents the direction around the axis of rotation R (hereinafter also referred to as the direction around the axis D2).

[0013] The type of rotating shaft R is not particularly limited, as long as it is a rotating shaft that is subject to braking. In the example shown in Figure 1, the rotating shaft R is the axle of the vehicle. The axle may be a drive shaft that is rotated by a drive device such as a motor, or it may be a driven shaft that is not connected to a drive device.

[0014] As shown in Figures 2 and 3, the braking device 1 comprises a disc 2, a receiving portion 3, a movable portion 4, and a drive portion 5. The braking device 1 also further comprises a control unit (not shown).

[0015] The disc 2 is fixed to the rotation axis R such that its central axis 21 coincides with the axis of the rotation axis R. The disc 2 is a component that receives braking force from the receiving portion 3 and the movable portion 4, transmits the received braking force to the rotation axis R, and thereby brakes the rotation of the rotation axis R.

[0016] The disk 2 has a through hole 22 in its radial center through which the rotating shaft 2 is inserted. The through hole 22 has a diameter that allows the rotating shaft R to pass through. The disk 2 is fixed to the rotating shaft R so as not to be displaced around the axis of the rotating shaft R and in the axial direction. The manner of fixing is not particularly limited as long as the disk 2 is fixed to the rotating shaft R so as not to be displaced around the axis of the rotating shaft R and in the axial direction. In this embodiment, the disk 2 comprises a disc-shaped disk body 23 and a fixing member 24 that fixes the disk body 23 to the outer circumference of the rotating shaft R. In this embodiment, the disk body 23 has a through hole 231 in its radial center through which the fixing member 24 is inserted. The fixing member 24 has a cylindrical hub 241 that connects the disk body 23 and the rotating shaft R. The fixing member 24 also has a key (machine key) 242 and a nut 244 that fix the hub 241 to the rotating shaft R. The key 242 prevents the hub 241 from rotating in the direction D2 around the axis of rotation R. The nut 244 prevents the hub 241 from moving in the axial direction D1 around the axis of rotation R.

[0017] In the examples shown in FIGS. 2 and 3, key grooves are formed on the outer peripheral surface of the rotating shaft R and the inner peripheral surface of the hub 241. The key 242 is inserted into the key groove of the rotating shaft R and the key groove of the hub 241 to fix the hub 241 to the rotating shaft R. Further, the rotating shaft R has a male thread portion R1 concentric with the center line of the rotating shaft R at its tip end. With the male thread portion R1 inserted into the through hole 22 of the hub 241, a nut 244 is screwed onto the male thread portion R1, and the hub 241 is pressed in the axial base end direction D12 by the nut 244, thereby fixing the hub 241 to the rotating shaft R. Also, the fixing member 24 has a male thread member (bolt) 243 for fixing the disk body 23 to the hub 241. The hub 241 has a female thread portion that engages with the male thread member 243. The disk body 23 has a screw insertion hole 233 through which the leg portion of the male thread member 243 is inserted.

[0018] The fixing member 24 further has a pressing plate 245 that presses the surface of the disk body 23 on the axial tip end side D11 toward the hub 241 (in the axial base end direction D12). The pressing plate 245 is formed in a ring shape. The pressing plate 245 is configured to press a portion on the opposite side of the portion (hub side contact portion) that contacts the hub 241 on the surface of the disk body 23 on the axial base end side D12 (the portion corresponding to the hub side contact portion on the surface of the disk body 23 on the axial tip end side D11). That is, the disk body 23 is sandwiched between the hub 241 and the pressing plate 245. The disk body 23 is fixed between the hub 241 and the pressing plate 245 by the tightening force of the male thread member 243 in the state of being sandwiched between the hub 241 and the pressing plate 245. Specifically, the pressing plate 245 has a through hole at a position corresponding to the female thread portion of the hub 241. The through hole has a recess for holding the head of the male thread member 243. When the male thread member 243 inserted into the through hole and the screw insertion hole 233 of the disk body 23 engages with the female thread portion of the hub 241, the head of the male thread member 243 presses the pressing plate 245 against the disk body 23. Thereby, both surfaces of the disk body 23 are pressed by the hub 241 and the pressing plate 245, and the disk body 23 is fixed between the hub 241 and the pressing plate 245.

[0019] The outer circumference of the hub 241 has a notch cut out from the end face D11 on the shaft tip side, with a region (cylindrical region) equal to the thickness of the disc body 23. The inner circumference of the disc body 23 is fitted into this notch. The inner diameter of this notch (cylindrical region) and the inner diameter of the through hole 231 in the disc body 23 are approximately the same. With the inner circumference of the disc body 23 fitted into the notch, the disc body 23 can be more firmly fixed to the hub 241 by fixing it with the pressing member 245 and the male screw member 243. Note that the manner in which the disc 2 is fixed to the rotating shaft R is not limited to the above example. For example, instead of connecting with the key 242, the hub 241 may be fixed to the rotating shaft R by press-fitting or shrink-fitting the rotating shaft R into the through hole of the hub 241.

[0020] As shown in Figures 2 and 3, the disk 2 (specifically the disk body 23) is configured to be elastically deformable in the direction D1 along the rotation axis R (axial direction). By elastically deforming in the axial direction D1, the disk 2 can elastically deform in a direction toward the receiving portion 3 and press against the receiving portion 3 (see Figure 3). Specifically, the movable portion 4, which receives a pressing force from the drive unit 5 toward the receiving portion 3, moves toward the receiving portion 3 (transition from the state in Figure 2 to the state in Figure 3). The disk 2 (specifically the disk body 23) located between the receiving portion 3 and the movable portion 4 receives a pressing force from the movable portion 4 toward the receiving portion 3. The radial center of the disk 2 is fixed to the rotation axis R. Therefore, when the disk 2 is pressed by the movable portion 4, the radial center of the disk 2 (the part fixed to the rotation axis R) does not displace, and only the portion of the disk 2 radially outside the center is elastically displaced (elastically deformed) toward the receiving portion 3 (see Figure 3). In disc 2, the portion that elastically deforms toward the receiving portion 3 contacts and presses against the receiving portion 3. The contact between disc 2 and the movable portion 4 generates a braking force due to friction. Furthermore, the contact between disc 2 and the receiving portion 3 also generates a braking force due to friction. As a result, disc 2 receives braking forces from both the movable portion 4 and the receiving portion 3. That is, disc 2 receives braking forces from both sides in the axial direction D1 (see Figure 3). Therefore, disc 2 can receive a large braking force. Disc 2 transmits the received braking force to the rotating shaft R. Therefore, the braking device 1 can brake the rotation of the rotating shaft R with a large braking force.

[0021] The disk 2 (specifically, the disk body 23) (see Fig. 3) satisfies the following conditions: (i) when pressed by the movable part 4, it elastically deform in the axial direction D1 to press the receiving part 3; (ii) the part contacting the movable part 4 and the part contacting the receiving part 3 generate braking force due to frictional force; and (iii) the braking force received from the movable part 4 and the receiving part 3 is transmitted to the rotating shaft R during rotation or when it stops (the rotational torque of the rotating shaft R is transmitted to the movable part 4 and the receiving part 3). If these conditions are met, its form is not particularly limited. That is, the disk 2 has elasticity that satisfies the condition (i) (the property of deforming when receiving an external force and returning to its original shape when the external force is removed), friction (friction coefficient) that satisfies the condition (ii), and strength that satisfies the condition (iii). The rotational torque mentioned here is the rotational torque of the rotating shaft R during rotation or when it stops.

[0022] In this embodiment, the disk 2 (specifically, the disk body 23) is composed of a shape and material that satisfy the above conditions (i) to (iii). In this embodiment, the disk 2 has a disk shape. Also, the disk 2 has a radius and thickness that satisfy the above conditions (i) to (iii). The shape and material of the disk 2 can be set according to the rotational torque of the rotating shaft R and the diameter of the rotating shaft R. Examples of materials that satisfy this condition include steel and stainless steel.

[0023] Also, if the disk 2 (specifically, the disk body 23) satisfies the above conditions (i) to (iii), it may be composed of one disk-shaped piece 232, or may be composed of a plurality of disk-shaped pieces 232 stacked in the thickness direction (see Figs. 2 and 3). In the examples shown in Figs. 2 and 3, the disk 2 is composed of a plurality of disk-shaped pieces 232 stacked in the thickness direction. That is, the number of disk-shaped pieces 232 constituting the disk 2 is plural (two in the examples shown in Figs. 2 and 3). More specifically, the disk body 23 is composed of a plurality (for example, two) of disk-shaped pieces 232 stacked in the thickness direction.

[0024] If a braking force is generated between the disc 2 and the receiving portion 3 due to friction, the configuration for generating the friction force is not particularly limited. In this embodiment, the portion of the disc 2 that contacts the receiving portion 3 is made of a friction material. Specifically, the disc 2 has a friction member 25 at the position where it contacts the receiving portion 3. The friction member 25 is a brake pad having a predetermined thickness. Also in this embodiment, the portion of the disc 2 that contacts the movable portion 4 is made of a friction material. Specifically, the disc 2 has a friction member 25 at the position where it contacts the movable portion 4. The friction member 25 is a brake pad having a predetermined thickness. The friction member 25 has high friction (high coefficient of friction).

[0025] The configuration in which braking force is generated by friction between the disc 2 and the receiving portion 3 is not limited to the above example. For example, the portion of the receiving portion 3 that contacts the disc 2 may be made of a friction material. Specifically, the receiving portion 3 may have a friction member (not shown) at the position where it contacts the disc 2. The friction member is a brake pad having a predetermined thickness. Also, the portion of the movable portion 4 that contacts the disc 2 may be made of a friction material. Specifically, the movable portion 4 may have a friction member (not shown) at the position where it contacts the disc 2. The friction member is a brake pad having a predetermined thickness.

[0026] As shown in Figures 2 and 3, the receiving portion 3 is provided so as to face one side of the disc 2 (the side D11 on the shaft tip side). The receiving portion 3 is a side plate that generates a braking force due to friction between itself and the disc 2 by contacting the disc 2. When the braking device 1 is not braking (see Figure 2), the receiving portion 3 has a predetermined gap G1 between itself and the disc 2. In the example shown in Figure 2, when the braking device 1 is not braking, the receiving portion 3 has a gap G1 between itself and the friction member 25 of the disc 2 (the size of the gap G1 is greater than zero). When braking (see Figure 3), the gap G1 disappears (the size of the gap G1 becomes zero). The receiving portion 3 and the field core 51, which will be described later, are in a positional relationship with a certain distance S1 between them. The configuration of the receiving portion 3 is not particularly limited as long as it can generate a braking force due to friction between itself and the disc 2 by contacting it. In this embodiment, the receiving portion 3 is configured in the shape of a disc.

[0027] In the examples shown in Figures 1 to 3, the receiving portion 3 has a through hole 31 through which the tip of the rotating shaft R can be inserted. Also in the examples shown in Figures 1 to 3, the braking device 1 includes a spacing holding portion 6 that maintains the distance S1 between the receiving portion 3 and the field core 51. The configuration of the spacing holding portion 6 is not particularly limited as long as it can maintain the distance S1 between the receiving portion 3 and the field core 51. In the examples shown in Figures 2 and 3, the receiving portion 3 includes a plurality of male screw members 61 that are inserted into a plurality of screw insertion holes 32 formed along the periphery of the receiving portion 3, and a cylindrical spacer 62 into which the legs of the male screw members 61 are inserted. The tips of the plurality of male screw members 61 are screwed into the female threads of a plurality of screw holes 511 formed along the periphery of the field core 51. The spacer 62 is provided so as to be interposed between the receiving portion 3 and the field core 51. This makes it possible to maintain a constant distance S1 between the receiving portion 3 and the field core 51.

[0028] As shown in Figures 2 and 3, the movable part 4 is positioned to face the other side of the disk 2 (the side D12 on the shaft base end). The movable part 4 is configured to move in an approaching direction, which is the direction towards the disk 2, and in a moving away direction, which is the direction away from the disk 2. The approaching direction is the same direction as the shaft tip direction D11, and will hereinafter be referred to as the approaching direction D11. The moving away direction is the same direction as the shaft base end direction D12, and will hereinafter be referred to as the moving away direction D12.

[0029] When the braking device 1 is not braking (see Figure 2), the movable part 4 has a predetermined gap G2 between it and the disc 2. In the example shown in Figure 2, when the braking device 1 is not braking, the movable part 4 has a predetermined gap G2 between it and the friction member 25 of the disc 2 (the size of the gap G2 is greater than zero). When the braking device 1 is braking (see Figure 3), the gap G2 disappears (the size of the gap G2 becomes zero). The configuration of the movable part 4 is not particularly limited, as long as it can generate a braking force due to friction between itself and the disc 2 by contacting the disc 2. In this embodiment, the movable part 4 is configured in the shape of a disc.

[0030] In this embodiment, the movable part 4 is a movable iron core (armature) that can move as described above. The movable part 4 is made of a magnetic material. Specifically, when the field core 51 is magnetized by the electromagnetic coil 52 described later, the movable part 4 is also magnetized and attracted to the field core 51. As a result, the movable part 4 can move in the separation direction D12 (transitioning from the state shown in Figure 3 to the state shown in Figure 2). In the example shown in Figure 2, the movable part 4 is attracted to the field core 51 and comes into contact with the field core 51 (the distance between it and the field core 51 becomes zero).

[0031] A control unit (not shown) controls the energization state of the electromagnetic coil 52 (for example, the voltage of the electromagnetic coil 52). The control unit is not particularly limited as long as it can control the energization state of the electromagnetic coil 52, and can use known computers including, for example, a centralized processing unit (CPU), a storage device such as an HDD or SSD, and memory such as RAM or ROM.

[0032] The drive unit 5 is configured to move the movable part 4 in the approaching direction D11 and the separating direction D12. The configuration of the drive unit 5 is not particularly limited as long as it can move the movable part 4 in the approaching direction D11 and the separating direction D12. In this embodiment, the drive unit 5 comprises a field core 51, an electromagnetic coil 52, and a compression coil spring 53 (see Figure 3). The field core 51 is a fixed iron core and is made of a magnetic material.

[0033] Specifically, the field core 51 is magnetized by the energization of the electromagnetic coil 52, thereby magnetizing the movable part 4. This allows the field core 51 to magnetically attract the movable part 4 (moving it in the direction D12 towards the base of the shaft) (see Figure 2). In the example shown in Figure 2, the magnetic force with which the field core 51 attracts the movable part 4 is greater than the elastic force of the compression coil spring 53 (the pressing force that attempts to move the movable part 4 in the direction D11 towards the tip of the shaft). As a result, the movable part 4 is attracted to the field core 51 and comes into contact with it. When the movable part 4 is in contact with the field core 51, the movable part 4 has a predetermined gap G2 between it and the disk 2 (see Figure 2). This results in a state where no braking force due to friction is generated between the movable part 4 and the disk 2 (unbraked state).

[0034] Furthermore, the control unit can control the strength of the magnetic field generated by the electromagnetic coil 52 by controlling the voltage of the electromagnetic coil 52 (for example, weakening the magnetic field strength or making the magnetic field strength zero). As a result, the magnetization of the field core 51 due to the energization of the electromagnetic coil 52 weakens, or the energization stops and the field core 51 becomes demagnetized. As a result, the magnetic force of the movable part 4 also weakens or becomes demagnetized. Therefore, the magnetic force that the field core 51 exerts on the movable part 4 (moving it in the direction D12 towards the base of the shaft) becomes smaller than the elastic force (pressing force) of the compression coil spring 53. As a result, the compression coil spring 53 presses the movable part 4 in the direction D11 towards the tip of the shaft, moving the movable part 4 in the direction D11 towards the tip of the shaft (see Figure 3). As a result, the movable part 4 moves away from the field core 51 and comes into contact with the disk 2, pressing against the disk 2. This generates a braking force due to friction between the movable part 4 and the disk 2 (braking state).

[0035] As shown in Figures 2 and 3, the electromagnetic coil 52 is located inside the field core 51. Specifically, an annular groove 512 is formed on the surface of the field core 51 at the shaft tip side D11 (the surface facing the movable part 4), concentric with the outer circumference of the field core 51. The annular electromagnetic coil 52 is located inside this groove 512. When the electromagnetic coil 52 is energized, the field core 51 and the movable part 4 are magnetized. This allows the field core 51 to magnetically attract the movable part 4 towards the shaft base end side D12 (see Figure 2). Furthermore, the control unit can control the strength of the magnetic field produced by the electromagnetic coil 52 by controlling the voltage supplied to the electromagnetic coil 52 (for example, weakening the magnetic field strength or making the magnetic field strength zero). This weakens the magnetization of the field core 51 and the movable part 4, or demagnetizes them. As a result, the magnetic force with which the field core 51 attracts the movable part 4 becomes smaller than the elastic force (compression force) of the compression coil spring 53, and the movable part 4 moves toward the shaft tip side D11 due to the elastic force of the compression spring 53 (see Figure 3).

[0036] As shown in Figure 3, the compression coil spring 53 is located inside the field core 51. Specifically, a number of recesses 513 are formed along the outer circumference of the field core 51 on the surface of the field core 51 at the shaft tip side D11 (the surface facing the movable part 4). The compression coil spring 53 is located inside these recesses 513. In its natural state, the tip of the compression coil spring 53 is positioned to protrude from the surface of the field core 51 at the shaft tip side D11. The compression coil spring 53 constantly presses the movable part 4 against the shaft tip side D11. When the elastic force (pressing force) of the compression coil spring 53 is less than the magnetic force that attracts the movable part 4 to the field core 51, the movable part 4 comes into contact with the field core 51 due to the magnetic force of the field core 51 (see Figure 2). On the other hand, when the current supply to the electromagnetic coil 52 is controlled, weakening the magnetization of the field core 51 and the movable part 4, or when the current supply is stopped and the field core 51 and the movable part 4 are demagnetized, the force with which the field core 51 attracts the movable part 4 becomes smaller than the elastic force of the compression coil spring 53. Therefore, the elastic force of the compression coil spring 53 causes the movable part 4 to move away from the field core 51 and come into contact with the disk 2 (see Figure 3).

[0037] As shown in Figure 3, when the braking device 1 is applied, the drive unit 5 moves the movable unit 4 in the approaching direction D11, causing the movable unit 4 to press the disc 2 toward the receiving unit 3. The disc 2 then elastically deforms toward the receiving unit 3, causing the disc 2 to press against the receiving unit 3. In this embodiment, the movable unit 4 presses the portion of the disc 2 radially outward from the portion fixed to the rotation axis R (in the example shown in Figure 3, the portion of the disc body 23 fixed to the fixing member 24). Specifically, the movable unit 4 presses the region of the disc 2 that is a predetermined distance away from the portion fixed to the rotation axis R. This makes the disc 2 more susceptible to elastic deformation toward the receiving unit 3 (axis tip side D11) starting from the portion fixed to the rotation axis R. In the example shown in Figure 3, the disc 2 elastically deforms so as to tilt toward the receiving unit 3 (axis tip side D11) starting from the portion fixed to the rotation axis R. In the example shown in Figure 3, the movable part 4 presses the friction member 25 on the shaft base end side D12 of the disk 2 toward the receiving part 3. As a result, the disk body 23 elastically deforms toward the shaft tip side D11 in the portion radially inward of the friction member 25. Due to this elastic deformation, the friction member 25 on the shaft base end side D12, the friction member 25 on the shaft tip side D11, and the portion of the disk body 23 corresponding to the friction member 25 move toward the shaft tip direction D11. As a result, the friction member 25 on the shaft tip side D11 presses against the receiving part 3.

[0038] In the braking device 1 of this embodiment, the disc 2 is fixed to the rotating shaft R so as not to be displaced in the axial direction and direction relative to the rotating shaft R (see Figures 2 and 3). That is, in this embodiment, the disc 2 is fixed to the rotating shaft R so as not to be displaced in the axial direction D2 and direction D1 relative to the rotating shaft R, and the means of fixing the disc 2 to the rotating shaft R does not employ the meshing of splines. For this reason, unlike the electromagnetic brake device of Patent Document 1, this embodiment does not generate vibration or noise due to the meshing of splines. Also, because the meshing of splines is not employed, unlike the electromagnetic brake device of Patent Document 1, problems caused by backlash do not occur. In other words, the accuracy of stopping the rotation of the rotating shaft R relative to the disc 2 can be improved. Therefore, the rotating rotating shaft R can be stopped with high accuracy at a desired rotation angle. In addition, if unnecessary rotational torque is applied to the stopped rotating shaft R, the stopped state of the rotating shaft R can be maintained with high accuracy. Furthermore, unlike Patent Document 1, in this embodiment, relative sliding (sliding in the axial direction D2 and sliding in the axial direction D1) does not occur at the connection between the rotating shaft R and the disk 2. Therefore, in this embodiment, no wear due to relative sliding occurs, and no wear particles are generated. Consequently, in this embodiment, the accuracy of stopping the rotation of the rotating shaft R relative to the disk 2 can be steadily improved over time.

[0039] In the examples shown in Figures 2 and 3, the disk 2 is composed of multiple disk-shaped pieces 232 stacked in the thickness direction. The number of stacked disk-shaped pieces 232 is not particularly limited. In the examples shown in Figures 2 and 3, the disk 2 is composed of two disk-shaped pieces 232. However, the disk 2 may be composed of three or more disk-shaped pieces 232.

[0040] When disk 2 is composed of multiple disk-shaped pieces 232 stacked in the thickness direction (hereinafter also referred to as the former case), disk 2 is more easily elastically deformed compared to when disk 2 of the same thickness is composed of a single disk-shaped piece 232 (i.e., the thickness of disk-shaped piece 232 is greater than the thickness of disk-shaped piece 232 in the former case) (hereinafter also referred to as the latter case). The reason for this is that, theoretically, the external force required for deflection is proportional to the cube of the plate thickness. For example, if the thickness of disk-shaped piece 232 in the former case is 1 / 2 the thickness of disk-shaped piece 232 in the latter case, the external force required for deflection of disk-shaped piece 232 in the former case will be 1 / 8 of that in the latter case (i.e., (1 / 2) cubed). In the former case, since the two disc-shaped pieces 232 are superimposed, the external force required for the deflection of the disc-shaped pieces 232 in the former case is 1 / 4 of that in the latter case (i.e., twice (1 / 8)). Therefore, the external force required for the deflection of the disc 2 in the former case is reduced to 1 / 4 of that in the latter case.

[0041] The principle mentioned above, that the external force required for deflection is proportional to the cube of the plate thickness, is based on the equation for plate deflection.

[0042] The equation for deflection is expressed as follows: σA=PL 3 / (3EI) (Equation 1) Here, σ is the deflection, A is the cross-sectional area of ​​the cantilever beam, P is the load on the free end of the cantilever beam, L is the length of the cantilever beam, E is Young's modulus, and I is the second moment of area.

[0043] The second moment of area of ​​a cantilever beam with a rectangular cross-section is expressed by the following formula. I=bh 3 / 12 (Formula 2) Here, b represents the width of the cross-section, and h represents the height (thickness) of the cross-section.

[0044] From Equation 1, it can be seen that in order to reduce the external force P required for the deflection of the disc-shaped piece 232, the second moment of area (I) should be reduced. Furthermore, from Equation 2, it can be seen that in order to reduce the second moment of area (I), the thickness (h) of the disc-shaped piece 232 should be reduced. Also, from Equations 1 and 2, it can be seen that the external force P required for the deflection of the disc-shaped piece 232 is proportional to the cube of the thickness (h) of the disc-shaped piece 232.

[0045] In the examples shown in Figures 2 and 3, a disc-shaped piece 232 located on one side of the disc 2 (shaft tip side D11) and another disc-shaped piece 232 located on the other side of the disc 2 (shaft base end side D12) have friction material. This allows a braking force to be generated by friction between the disc-shaped piece 232 located on one side of the disc 2 and the receiving part 3. Furthermore, a braking force can be generated by friction between the disc-shaped piece 232 located on the other side of the disc 2 and the movable part 4 (see Figure 3). In the examples shown in Figures 2 and 3, the friction material is a friction member 25 having a predetermined thickness. The friction member 25 is provided on the disc-shaped piece 232 so as to protrude from the surface on which the friction member 25 is provided.

[0046] In this embodiment, the multiple disc-shaped pieces 232 are arranged to slide against each other when they undergo elastic deformation. When multiple overlapping disc-shaped pieces 232 undergo elastic deformation (for example, when they bend), differences in elastic deformation, such as curvature, may occur in the direction of elastic deformation. When differences in elastic deformation occur, the mating surfaces of the pieces tend to shift (slide) against each other. If the mating surfaces are designed to be difficult to shift (slide) against each other, the multiple disc-shaped pieces 232 may hinder each other's elastic deformation. In contrast, if the multiple disc-shaped pieces 232 are arranged to slide against each other when they undergo elastic deformation, such problems do not occur. Therefore, the multiple disc-shaped pieces 232 can undergo elastic deformation smoothly, and the external force required for elastic deformation can be easily reduced.

[0047] In this embodiment, a lubricant is applied to the mating surfaces of the multiple disc-shaped pieces 232. As described above, when the multiple disc-shaped pieces 232 are arranged to slide against each other during elastic deformation, the disadvantage of the multiple disc-shaped pieces 232 hindering each other's elastic deformation does not occur. Therefore, by applying a lubricant to the mating surfaces of the multiple disc-shaped pieces 232, the sliding of the multiple disc-shaped pieces 232 against each other during elastic deformation is promoted. Consequently, the multiple disc-shaped pieces 232 can undergo elastic deformation more smoothly, and the external force required for elastic deformation can be reduced more easily.

[0048] According to the braking device 1 of this embodiment, the disc 2 is elastically deformed toward the receiving portion 3 in order to transition from a state in which a predetermined gap G1 is provided between the receiving portion 3 and the disc 2 to a state in which the disc 2 presses against the receiving portion 3. When the disc 2 is brought into contact with the receiving portion 3 by elastic deformation of the disc 2, the magnitude of the force with which the disc 2 presses against the receiving portion 3 is the value obtained by subtracting the force required to elastically deform the disc 2 from the elastic force of the compression coil spring 53. Therefore, in order to obtain a large braking force, it is preferable that the force required to elastically deform the disc 2 is small.

[0049] Therefore, in this embodiment, the disk 2 is composed of multiple disk-shaped pieces 232 that are stacked in the thickness direction. When the disk 2 is composed of multiple disk-shaped pieces 232 that are stacked in the thickness direction, the disk 2 is more elastically deformable compared to when the disk 2 of the same thickness is composed of a single disk-shaped piece 232. For this reason, if the total thickness of the disk 2 is the same in the former (multiple disk-shaped pieces 232) and the latter (one disk-shaped piece 232), the former can be elastically deformed with a smaller external force. Thus, by composing the disk 2 with multiple disk-shaped pieces 232 that are stacked in the thickness direction, a greater braking force can be obtained. Furthermore, since the strength of the disk 2 (specifically the disk body 23) required to transmit the braking force to the rotation axis R depends on the total thickness of the disk 2, the former can also be made strong enough to transmit the braking force to the rotation axis R.

[0050] Next, an example of how to use the braking device 1 according to this embodiment will be described with reference to Figures 2 and 3. For example, consider the case where the rotation of a rotating shaft R is being braked. When the braking device 1 is not braking (see Figure 2), the rotating shaft R rotates with a gap G1 between the disc 2 and the receiving part 3, and a gap G2 between the disc 2 and the movable part 4. The electromagnetic coil 52 is energized, and the force with which the field core 51 pulls the movable part 4 is greater than the elastic force of the compression coil spring 53 (see Figure 2).

[0051] Next, the braking device 1 is transitioned to the braking state. First, the control unit controls the strength of the magnetic field produced by the electromagnetic coil 52 by controlling the voltage of the electromagnetic coil 52 (for example, weakening the magnetic field strength or making the magnetic field strength zero). As a result, the force with which the field core 51 attracts the movable part 4 becomes smaller than the elastic force of the compression coil spring 53. This causes the elastic force of the compression coil spring 513 to move the movable part 4 toward the receiving part 3, and the movable part 4 presses against the disc 2. By pressing the disc 2 with the movable part 4, the disc 2 is elastically deformed toward the receiving part 3, causing the disc 2 to press against the receiving part 3. This allows braking force to be applied to the disc 2 from both sides. The braking force applied to the disc 2 is transmitted to the rotating shaft R, and the rotation of the rotating shaft R is braked (see Figure 3).

[0052] To return to the unbraked state, the control unit controls the voltage of the electromagnetic coil 5, thereby increasing the strength of the magnetic field produced by the electromagnetic coil 52. As a result, the force with which the field core 51 attracts the movable part 4 becomes greater than the elastic force of the compression coil spring 53. This causes the magnetic force to move the movable part 4 away from the receiving part 3, against the elastic force (pressing force) of the compression coil spring 513. As a result, the movable part 4 separates from the disk 2, and the disk 2 returns to its shape before elastic deformation (natural state). This returns to a state where there is a gap G1 between the disk 2 and the receiving part 3, and a gap G2 between the disk 2 and the movable part 4 (unbraked state) (see Figure 2). [Explanation of Symbols]

[0053] 1 Braking device 2 discs 21 Center axis 22 Through hole 23. Disc body 231 Through hole 232 disc-shaped pieces 233 Screw insertion holes 24 Fixing member 241 Hub 242 keys 243 Male threaded component 244 nuts 245 Pressing plate 25 Friction Member 3 Receiving part 31 Through hole 32 Screw insertion holes 4 Moving parts 5 Drive Unit 51 Field Core 511 Screw holes 512 Groove 513 Recess 52 Electromagnetic Coil 53 Compression coil spring 6 Spacing section 61 Male threaded member 62 Spacers D1 Direction along the axis of rotation (axial direction) D11 Shaft tip direction (shaft tip side), approach direction D12 Shaft base end direction (shaft base end side), separation direction Direction around the D2 axis G1 Gap between the receiving part and the disc G2 Gap between the movable part and the disc R rotation axis R1 Male thread section S1 Distance between the receiving part and the field core

Claims

1. A braking device that brakes the rotation of a rotating shaft that is the object to be braked, A disk fixed to the rotating shaft such that its central axis coincides with the axis of the rotating shaft, A receiving portion provided so as to face one side of the disk, A movable part is provided so as to face the other side of the disk and is movable in an approaching direction, which is the direction toward the disk, and in a moving direction, which is the direction toward the disk. The movable part is further equipped with a drive unit that moves it in the approaching direction and the separating direction, The disk is fixed to the rotating shaft so as not to be displaced in the direction of the axis of rotation and in the axial direction relative to the rotating shaft. When the disc and the receiving portion come into contact, a braking force is generated due to friction. When the disc and the movable part come into contact, a braking force is generated due to friction. The disk is elastically deformable in the direction along the axis of rotation, When the braking device is not braking, a predetermined gap is provided between the disc and the receiving portion, and between the disc and the movable portion. During braking of the braking device, the drive unit moves the movable part in the approaching direction, causing the movable part to press the disc toward the receiving part, and the disc elastically deforms toward the receiving part, thereby pressing the disc toward the receiving part. The aforementioned disk is composed of a plurality of disk-shaped pieces stacked in the thickness direction, A braking device in which the plurality of disc-shaped pieces are arranged to be slidable relative to each other when elastically deformed.

2. A braking device for braking the rotation of a rotating shaft which is the object to be braked, A disk fixed to the rotating shaft such that its central axis coincides with the axis of the rotating shaft, A receiving portion provided so as to face one side of the disk, A movable part is provided so as to face the other side of the disk and is movable in an approaching direction, which is the direction toward the disk, and in a moving direction, which is the direction toward the disk. The movable part is further equipped with a drive unit that moves it in the approaching direction and the separating direction, The disk is fixed to the rotating shaft so as not to be displaced in the direction of the axis of rotation and in the axial direction relative to the rotating shaft. When the disc and the receiving portion come into contact, a braking force is generated due to friction. When the disc and the movable part come into contact, a braking force is generated due to friction. The disk is elastically deformable in the direction along the axis of rotation, When the braking device is not braking, a predetermined gap is provided between the disc and the receiving portion, and between the disc and the movable portion. During braking of the braking device, the drive unit moves the movable part in the approaching direction, causing the movable part to press the disc toward the receiving part, and the disc elastically deforms toward the receiving part, thereby pressing the disc toward the receiving part. The aforementioned disk is composed of a plurality of disk-shaped pieces stacked in the thickness direction, A braking device in which a lubricant is applied to the mating surfaces of the plurality of disc-shaped pieces.

3. The braking device according to claim 1 or 2, wherein the disc-shaped piece located on one side and the disc-shaped piece located on the other side have a friction material.

4. The braking device according to claim 1 or 2, wherein the disc is composed of two disc-shaped pieces.

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