Safety brake for railway vehicle

Abstract

The purpose of the present invention is to provide a compact safety brake for a railway vehicle. A safety brake (100) for a railway vehicle according to the present disclosure is provided with: a braking shaft (1) in at least part of which screw thread is formed; a braking unit (2) for holding the braking shaft (1) at a predetermined angle of rotation if rotation of a wheel (29) of the railway vehicle is not decelerated, and relaxing the hold on the braking shaft (1) if rotation of the wheel (29) is decelerated; a first support section (10) for rotatably supporting the braking shaft (1); a braking coil spring (19) for pressing the first support section (10) if rotation of the wheel (29) is not decelerated; a second support section (14) for supporting the braking coil spring (19) at a position facing the first support section (10); and a linear motion unit (17) that is contained in the braking coil spring (19) and is in contact with the screw thread of the braking shaft (1), and is connected to the second support section (14) and causes the second support section (14) to move rectilinearly toward the wheel (29) to decelerate rotation of the wheel (29).

Description

Safety Brake for Railway Vehicles

[0001] The present disclosure relates to a safety brake for railway vehicles.

[0002] The braking system for railway vehicles is composed of a service brake, an emergency brake, a safety brake, etc. In each brake, the brake shoe mechanically applies a braking force to the wheel via a pressing bar or the like. The safety brake is used when the service brake fails. For example, in Patent Document 1, there is disclosed a safety brake for railway vehicles that changes the acting direction of the braking force of the safety brake provided on the upper part of the vehicle using a wedge when the service brake fails, and stops the movement of the wheel from the horizontal direction. The safety brake for railway vehicles disclosed in Patent Document 1 does not require power during operation, and thus effectively operates even when the power source of the vehicle is lost.

[0003] Japanese Patent Translation of PCT No. 2001-521468

[0004] However, the conventional safety brake for railway vehicles that changes the acting direction of the upper braking force and stops the movement of the wheel from the horizontal direction has a problem that the size becomes large in order to secure a large braking force while maintaining the operating stroke of the pressing bar until the brake shoe reaches the wheel. To do this, the angle of the wedge is made small and the length of the wedge in the operating direction of the wedge is increased.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a compact safety brake for railway vehicles.

[0006] The railway vehicle safety brake according to this disclosure comprises a brake shaft having a thread formed on at least a part of it; a braking part provided at one end of the brake shaft which holds the brake shaft at a predetermined rotation angle when the rotation of the railway vehicle's wheels is not to be decelerated and loosens the hold on the brake shaft when the rotation of the wheels is to be decelerated; a first support part connected to the brake part which rotatably supports the brake shaft; a brake coil spring supported by the first support part which presses against the first support part when the rotation of the wheels is not to be decelerated; a second support part which supports the brake coil spring at a position opposite to the first support part; and a linear motion part in which at least a part in the axial direction is enclosed in the brake coil spring, contacts the thread of the brake shaft, is connected to the second support part, and causes the second support part to move linearly toward the wheel, thereby decelerating the rotation of the wheel.

[0007] According to this disclosure, a compact configuration can be achieved by incorporating a linear motion unit into the braking coil spring that transmits braking force. This unit converts linear motion into rotational motion when decelerating the rotation of the wheel, and uses the linear motion to decelerate the rotation of the wheel.

[0008] This is a schematic cross-sectional view showing a railway vehicle safety brake according to Embodiment 1. This is a schematic cross-sectional view showing a railway vehicle safety brake according to Embodiment 1. This is a schematic cross-sectional view showing a railway vehicle safety brake according to Embodiment 1. This is a schematic cross-sectional view showing a railway vehicle safety brake according to Embodiment 1. This is a schematic cross-sectional view showing a railway vehicle safety brake according to Embodiment 1. This is a schematic cross-sectional view showing a railway vehicle safety brake according to Embodiment 1. This is a diagram illustrating the linear motion part of the railway vehicle safety brake according to Embodiment 1. This is a schematic cross-sectional view showing a railway vehicle safety brake according to Embodiment 1. This is a schematic configuration diagram showing a railway vehicle brake system according to Embodiment 1. This is a schematic cross-sectional view showing a railway vehicle safety brake according to Embodiment 2. This is a schematic cross-sectional view showing a railway vehicle safety brake according to Embodiment 3. This is a diagram illustrating the state in which the first teeth and the second teeth constituting the braking part of the railway vehicle safety brake according to Embodiment 3 are meshed. This is a schematic cross-sectional view showing a railway vehicle safety brake according to Embodiment 3. This is a diagram illustrating the state in which the railway vehicle safety brake according to Embodiment 4 is attached to the service brake. This is a schematic cross-sectional view of a safety brake for a railway vehicle according to Embodiment 5.

[0009] The embodiments described herein will be explained below with reference to the drawings. The same or corresponding parts in each drawing are denoted by the same reference numerals. In the description of the embodiments, the descriptions of the same or corresponding parts will be omitted or simplified as appropriate.

[0010] Embodiment 1. The railway vehicle safety brake 100 according to Embodiment 1 will be described with reference to Figures 1 to 10. In addition to service brakes and emergency brakes, railway vehicles are equipped with a railway vehicle safety brake 100. For example, when a service brake that operates using high-pressure air is used in a railway vehicle, if the high-pressure air leaks to the outside and the service brake becomes unable to operate, the railway vehicle safety brake 100 will operate and decelerate the wheels 29. Figure 1 is a schematic cross-sectional view showing the railway vehicle safety brake 100 when the braking unit 2 is in an energized state. The railway vehicle safety brake 100 comprises a brake shaft 1 with a screw formed on at least a part of it, a braking part 2 provided at one end of the brake shaft 1 which holds the brake shaft 1 at a predetermined rotation angle when the rotation of the railway vehicle's wheel 29 is not to be decelerated and loosens the hold on the brake shaft 1 when the rotation of the wheel 29 is to be decelerated, a first support part 10 connected to the brake part 2 which rotatably supports the brake shaft 1, a brake coil spring 19 supported by the first support part 10 which presses the first support part 10 when the rotation of the wheel 29 is not to be decelerated, a second support part 14 which supports the brake coil spring 19 at a position opposite to the first support part 10, and a linear motion part 17 which at least a part in the axial direction is enclosed in the brake coil spring 19, contacts the screw on the brake shaft 1 and is connected to the second support part 14 which moves the second support part 14 in a linear motion toward the wheel 29 and decelerates the rotation of the wheel 29. Here, the aforementioned case of decelerating the rotation of the railway vehicle's wheels 29 refers to the state in which the rotation of the wheels 29 is decelerated by the railway vehicle safety brake 100, and does not include the state in which the rotation of the wheels 29 is decelerated by service brakes other than the railway vehicle safety brake 100, and the rotation of the wheels 29 is not decelerated by the railway vehicle safety brake 100. The aforementioned case of not decelerating the rotation of the railway vehicle's wheels 29 refers to the state in which the rotation of the wheels 29 is not decelerated by the railway vehicle safety brake 100, and does not include the state in which the rotation of the wheels 29 is not decelerated by service brakes other than the railway vehicle safety brake 100, and the rotation of the wheels 29 is decelerated by the railway vehicle safety brake 100.

[0011] The braking shaft 1 has, at least a portion of it, an external thread formed on its outer circumference. The braking shaft 1 is indirectly connected to the brake shoe 28, and when the linearly moving member such as the brake shoe 28 moves in a linear motion, the braking shaft 1 rotates.

[0012] The braking unit 2 has the brake shaft 1 inserted into it and controls the rotational movement of the brake shaft 1. The braking unit 2 is an excitation-type electromagnetic brake that generates a magnetic field by energizing it, for example, and brakes the brake shaft 1 with magnetic force. When a railway vehicle is in normal operation, the safety brake does not operate, so by energizing the braking unit 2, the brake shaft 1 is held at a predetermined rotation angle to prevent it from rotating. On the other hand, the safety brake is activated when it is necessary to make an emergency stop on the railway vehicle. That is, the braking unit 2 loosens the holding torque that holds the brake shaft 1 to prevent it from rotating, making the brake shaft 1 rotatable. When the safety brake is activated, it is preferable to de-energize the braking unit 2 so that the compression of the brake coil spring 19 returns to normal. Alternatively, when the safety brake is activated, the impact torque on the wheels caused by the safety brake can be mitigated by changing the compression of the brake coil spring 19 at a desired speed by controlling the torque or speed of the braking unit 2. Furthermore, by loosening the holding torque and applying it in the reverse direction, the safety brake can be activated at a faster speed than when the braking unit 2 is de-energized.

[0013] The first support portion 10 is a member with a through hole into which the brake shaft 1 is inserted. The brake portion 2 is fixed to one surface of the first support portion 10 with bolts or the like, and the surface opposite to the surface to which the brake portion 2 is fixed is in contact with one end of the brake coil spring 19. The first support portion 10 is fixed to the vehicle's bogie or the like so as not to move due to the reaction force compressing the brake coil spring 19. The first support portion 10 has a through hole formed perpendicular to the surface to which the brake coil spring 19 is in contact, and the brake shaft 1 is inserted into the through hole.

[0014] The second support portion 14 is provided opposite the first support portion 10 and is in contact with one end of the braking coil spring 19, positioned with the braking coil spring 19 compressed toward the first support portion 10. Since the first support portion 10 is fixed and does not move, the second support portion 14 moves linearly in the direction of expansion and contraction of the braking coil spring 19 due to the reaction force it receives from the braking coil spring 19 when the braking coil spring 19 is compressed.

[0015] The braking coil spring 19 is a compression coil spring that contacts the first support portion 10 and is sandwiched between the second support portion 14, receiving a compressive load. The compressed compression coil spring gives the second support portion 14 a reaction force in the direction of the wheel 29. When the braking unit 2 is energized, it is compressed, and when it is de-energized, the braking coil spring 19 extends by pushing the second support portion 14 toward the wheel 29. Here, when the braking unit 2 is de-energized, the brake shoe 28 comes into contact with and presses against the wheel 29 within the time it takes for the braking coil spring 19 to reach its natural length.

[0016] The linear motion section 17 is attached and connected to the second support section 14, which supports the other end of the braking coil spring 19, by bolts or the like, and at least a portion of it in the axial direction is enclosed within the braking coil spring 19. Furthermore, for example, the linear motion section 17 has an internal thread formed on its inner circumference, which is in contact with the external thread of the third braking shaft section 1C. The internal thread is, for example, a female thread.

[0017] Next, a method for adjusting the operating speed of the second support unit 14 and the linear motion unit 17, which move linearly when the braking unit 2 is de-energized, will be explained. By using a linear motion unit 17 with a small-pitch female thread formed on its inner circumference and a braking shaft 1 with a small-pitch male thread formed on its inner circumference, the number of rotations of the braking shaft 1 required for the linear motion unit 17 to move linearly over a predetermined stroke length is large, resulting in a large inertia of linear motion. Inertia is also called moment of inertia. Therefore, the larger the inertia of linear motion, the more the inertia can offset a portion of the compressive reaction force received from the braking coil spring 19, thereby slowing down the linear motion speed of the linear motion unit 17. Conversely, by using a linear motion unit 17 with a large-pitch female thread formed on its inner circumference and a braking shaft 1 with a large-pitch male thread formed on its inner circumference, the number of rotations of the braking shaft 1 required for the linear motion unit 17 to move linearly over a predetermined stroke length is small, resulting in a small inertia of linear motion. Therefore, the smaller the inertia of the linear motion, the more effectively the compressive reaction force received from the braking coil spring 19 can be utilized to increase the speed of the linear motion of the linear motion unit 17. By changing the pitch of the internal screw in this way, the speed of the linear motion of the linear motion unit 17 toward the wheel 29 can be adjusted.

[0018] The operation of the railway vehicle safety brake 100 according to Embodiment 1 will now be described. When the braking unit 2 is energized, the braking shaft 1 is held at a predetermined rotation angle, which suppresses the conversion of linear motion to rotational motion in the linear motion unit 17. As a result, the braking shaft 1 cannot rotate, and therefore the linear motion unit 17 cannot perform linear motion. In other words, since the braking shaft 1 cannot rotate, the braking shaft 1 and the linear motion unit 17 remain stationary. Figure 2 is a schematic cross-sectional view showing the railway vehicle safety brake 100 when the braking unit 2 is de-energized. When the braking unit 2 is de-energized, the braking shaft 1 becomes rotatable, allowing the linear motion of the linear motion unit 17 to be converted into rotational motion of the braking shaft 1. The linear motion unit 17, to which the second support unit 14 is connected, receives a reaction force (force in the direction toward the wheel) from the force compressing the braking coil spring 19, causing it to move linearly toward the wheel, and the braking shaft 1 to rotate. As a result of the linear motion of the linear motion unit 17 toward the wheel, the rotation of the railway vehicle's wheel 29 is slowed down. Examples of when the braking unit 2 changes from an energized state to a de-energized state include power loss of the railway vehicle and failure of the service brake 26. If the service brake 26 fails, the braking unit 2 of the railway vehicle safety brake 100 receives an electrical signal, the braking unit 2 becomes de-energized, and the second support unit 14 and the linear motion unit 17 move linearly toward the wheel 29 due to the pressing force of the braking coil spring 19.

[0019] Furthermore, it is preferable that the braking shaft 1 is composed of a first braking shaft portion 1A enclosed within the braking section 2, a second braking shaft portion 1B connected to the first braking shaft portion 1A and enclosed within the first support portion 10, having a smaller diameter than the first braking shaft portion 1A, and a third braking shaft portion 1C enclosed within the linear motion portion 17, with a male thread formed thereon. If the diameters of the first braking shaft portion 1A and the second braking shaft portion 1B constituting the braking shaft 1 are different, a step is created, and the surface perpendicular to the axial length direction is pressed against the first support portion 10, allowing the braking shaft 1 to be supported in the axial length direction. In this case, when the braking section 2 is not energized, the pressed area slides, as shown in Figure 2. To make the sliding smoother, a lubricant such as grease may be applied to the surface where the first support portion 10 and the braking shaft 1 come into contact.

[0020] Furthermore, as shown in Figure 3, for example, when a bearing 24 is enclosed in the first support portion 10 and the second braking shaft portion 1B is inserted into the inner ring of the bearing 24, the bearing 24 is fixed to the first support portion 10 by the retaining plate 25 pressing its outer ring against the first support portion 10. In addition, a step provided on the braking shaft 1, where the diameter of the second braking shaft portion 1B, which has a different diameter from the first braking shaft portion 1A, changes, has a surface perpendicular to the axial length direction that presses against the side surface of the inner ring of the bearing 24. When the braking portion 2 is in an unexcited state, the braking shaft 1 receives a force toward the wheel 29 due to the pressing force generated by the braking coil spring 19, and when it is pressed against the inner ring of the bearing 24 enclosed in the first support portion 10, the bearing 24 supports the braking shaft 1 in the axial length direction. The bearing 24 also suppresses the rotational runout of the braking shaft 1. Figure 3 shows an example in which a deep groove ball bearing is used as the bearing 24 enclosed in the first support portion 10. However, the bearing 24 can be any other type as long as it can withstand the load in the axial direction in order to support the braking shaft 1 in the axial direction. Alternatively, the braking shaft 1 may be supported by multiple bearings 24.

[0021] Furthermore, as shown in Figure 4, for example, the first support portion 10 may be formed integrally with a cylindrical portion 13 that is enclosed within the braking coil spring 19 and has a smaller outer diameter than the second support portion 14, supporting the linear motion portion 17, and a first flange portion 12 that is connected to the braking portion 2, contacts the braking coil spring 19, and has a larger outer diameter than the cylindrical portion 13. The cylindrical portion 13 has the function of guiding the linear motion portion 17 to move linearly toward the wheel 29. In other words, by configuring the first support portion 10 with a cylindrical portion 13 that supports the outer circumference of the linear motion portion 17 and a first flange portion 12 that has a larger outer diameter than the cylindrical portion 13, and supporting one end of the braking coil spring 19 with the first flange portion 12, a compact configuration can be realized in which the linear motion portion 17 is enclosed within the braking coil spring 19 that transmits braking force, and converts linear motion into rotational motion in the unexcited state, thereby decelerating the rotation of the wheel 29 by linear motion.

[0022] The operation of the railway vehicle safety brake 100 when the first support portion 10 includes a cylindrical portion 13 will be described. When a brake shoe 28 is attached to a second support portion 14 that can move linearly together with the linear motion portion 17, and the braking portion 2 is in an unexcited state, the linear motion portion 17, the first support portion 10, and the brake shoe 28 are pressed against the wheel 29 by the pressing force generated by the braking coil spring 19, the brake shoe 28 receives a frictional force in the direction of rotation of the wheel 29, and a bending moment may be applied to the braking shaft 1. In this case, if there is no support from the cylindrical portion 13, the braking shaft 1 may bend, and linear motion may become impossible again. Therefore, as shown in Figure 5, if a cylindrical portion 13 that supports the linear motion portion 17 is provided, it is possible to prevent a state in which linear motion becomes impossible.

[0023] Alternatively, as shown in Figure 6, for example, the cylindrical portion 13 of the first support portion 10 may be pressed against the flange surface of a cylindrical fixing portion 11 that has a flange surface with an outer diameter smaller than the outer diameter of the second support portion 14 and supports the outer circumference of the linear motion portion 17, thereby supporting the outer circumference of the linear motion portion 17 via the fixing portion 11. With such a configuration, the first support portion is subdivided, making it possible to replace only localized components, including parts that wear out due to sliding, etc., thus reducing the weight of the components to be replaced and making maintenance such as replacement easier.

[0024] Alternatively, for example, the internal thread on the inner circumference of the linear motion section 17 may be a ball screw in which multiple first balls are arranged spirally on the threads. The first balls contact the male thread of the third braking shaft section 1C, which is inserted into the inner circumference of the linear motion section 17, causing the braking shaft 1 to rotate in conjunction with the linear motion of the linear motion section 17. By making the inner surface of the linear motion section 17 a ball screw, frictional resistance with the male thread of the third braking shaft section 1C can be reduced.

[0025] Furthermore, as shown in Figure 6 and Figure 7 at the A-A cross-sectional position in Figure 6, a ball screw with multiple balls arranged on its peaks is formed on the inner circumference of the linear motion part 17, and a ball spline nut containing a ball circulation part 22 for circulating the balls is formed on the fixing part 11 that supports the outer circumference of the linear motion part 17. A transfer groove 20 on which the balls roll is formed in the axial direction on the outer circumference of the linear motion part 17, and the rotation of the linear motion part 17 can be suppressed by the balls coming into contact with the transfer groove 20.

[0026] In Figure 7, the threads formed on the inner circumference of the linear motion section 17 and the outer circumference of the second braking shaft section 1B are omitted. The fixed section 11 of the first support section 10 encloses a plurality of second balls 21 and a ball circulation section 22. The ball circulation section 22 is a space formed so that the second balls 21 can roll and circulate. A plurality of second balls 21 are arranged in the ball circulation section 22 via a retainer, and the second balls 21 roll in the ball circulation section 22 and circulate in accordance with the linear motion of the linear motion section 17. Some of the second balls 21 are in contact with the transfer groove 20 of the linear motion section 17 on the inner circumferential surface of the fixed section 11. The transfer groove 20 supports the linear motion section 17 in the rotational direction by the contact of the second balls 21 with the linear motion section 17, preventing the linear motion section 17 from rotating.

[0027] The second support portion 14 may also be configured to have a second flange portion 15 and a pressing force transmission portion 16 that protrudes from the second flange portion 15 toward the wheel 29. The second support portion 14 is provided in contact with the braking coil spring 19 and is pushed toward the wheel 29 by the compression reaction force of the braking coil spring 19, and is fixed to the linear motion portion 17 by catching on a projection 18 provided on the outer circumference of the linear motion portion 17. The pressing force transmission portion 16 has the function of receiving the reaction force of the force that compresses the braking transmission spring 4 and transmitting this reaction force to the brake shoe 28.

[0028] The braking unit 2 may be, for example, a friction-type excitation electromagnetic brake comprising a braking transmission unit 3, a braking transmission spring 4, a contact pole 5, and a brake stator 9.

[0029] The braking transmission unit 3 is fixed to the braking shaft 1 in the rotational direction and in the axial direction. The braking transmission spring 4 is, for example, a leaf spring and is attached to the braking transmission unit 3. The braking transmission spring 4 rotates together with the rotation of the braking shaft 1. When the braking unit 2, which is an excitation-type electromagnetic brake, is in an excited state, the braking transmission spring 4 applies a force to the axle 5 that pulls it away from the friction member 6.

[0030] The axle 5 is attached to the other end of the braking spring 4 and rotates with the braking shaft 1 when the braking shaft 1 rotates. When the braking unit 2 is energized, the axle 5 is made of a soft magnetic material capable of forming a magnetic circuit inside, so when a magnetic field is formed by the winding coil 7 (described later), the axle 5 is magnetized inside. Therefore, it comes into contact with the friction member 6 of the brake stator 9 (described later), and the static friction force suppresses the rotation of the braking shaft 1, the braking transmission unit 3, and the braking spring 4. When the braking unit 2 is not energized, the braking spring 4 compresses towards the braking transmission unit 3, so the axle 5 moves away from the friction member 6 and returns to the braking transmission unit 3 side. As the axle 5 returns to the braking transmission unit 3 side, a gap is formed between the axle 5 and the friction member 6.

[0031] Since the braking spring 4 and the axle 5 are integrated with the braking transmission unit 3, the braking transmission unit 3, the braking spring 4, and the axle 9 rotate together with the braking shaft 1. In other words, when the rotation of the wheel 29 is reduced, the braking transmission unit 3, the braking spring 4, and the axle 9 rotate in the same direction as the rotation of the braking shaft 1.

[0032] The brake stator 9 comprises a friction member 6, a winding coil 7, and a coil case 8. The winding coil 7 is positioned opposite the abutment 5 via the friction member 6. The friction member 6 is made of, for example, a corrosion-resistant metal such as stainless steel, or a resin. A high static friction coefficient between the abutment 5 and the friction member 6 is desirable. The coil case 8 may be omitted, and the brake stator 9 may be configured such that the winding coil 7 is encased in resin, with the friction member 6 in contact with the resin.

[0033] Figure 8 shows a railway vehicle safety brake 100 using a friction-type excitation electromagnetic brake in the de-excited state. When the braking unit 2 is excited, the winding coil 7 is excited and generates a magnetic field. The generated magnetic field biases the axole 5, causing it to contact the friction member 6. The friction member 6 prevents the axole 5 from rotating together with the braking shaft 1 due to the static friction force generated between the axole 5 and the friction member 6. When the braking unit 2 is de-excited, the magnetic field disappears, so the axole 5 moves away from the friction member 6 and returns to the braking transmission unit 3 side due to the restoring force of the braking transmission spring 4, and the braking shaft 1 becomes rotatable. The pressing force generated by the braking coil spring 19 causes the linear motion unit 17 to which the second support unit 14 is attached to move linearly toward the wheel 29, and the motion mode is changed by the screw on the inner circumference of the linear motion unit 17, causing the braking shaft 1 to rotate. At this time, the braking transmission unit 3, the axle 5, and the braking transmission spring 4 rotate together with the braking shaft 1 while maintaining a gap between the axle 5 and the friction member 6.

[0034] Furthermore, as shown in Figure 9, the railway vehicle safety brake 100 is equipped with a brake cover 23 that covers the brake shaft 1, the linear motion section 17, the fixed section 11, and the cylindrical section 13 in order to suppress the intrusion of moisture or dust from the outside.

[0035] Furthermore, as shown in Figure 10, when the railway vehicle safety brake 100 is installed opposite the service brake 26 with the wheel 29 in between, the brake shoe 28 is positioned between the wheel 29 and the second support 14, on the extension of the direction of linear motion of the second support 14. By being pressed against the wheel 29 of the railway vehicle, it reduces the rotational speed of the wheel 29. When the braking unit 2 is de-energized, the brake shoe 28 is positioned on the extension of the direction of linear motion of the second support 14, thereby transmitting the pressing force generated by the braking coil spring 19 to the wheel 29 without changing the direction of action of the pressing force. When the braking unit 2 is energized, the brake shoe 28 is positioned away from the wheel 29. In addition, the second support 14 may have a retaining rod 27 at its tip, and the brake shoe 28 may be attached to the retaining rod 27. Therefore, the railway vehicle safety brake 100 according to this disclosure has a structure that presses the brake shoe 28 against the wheel 29 without changing the direction of action of the pressing force generated by compressing the braking transmission spring 4, and thus can be positioned adjacent to the service brake 26 in the horizontal direction.

[0036] As described above, the railway vehicle safety brake 100 according to Embodiment 1 is installed on a railway vehicle together with a service brake, etc., and slows down the rotation of the wheels when it is necessary to activate the railway vehicle safety brake, and comprises a brake shaft 1 with a screw formed on at least a part of it, a braking part 2 provided at one end of the brake shaft 1 which holds the brake shaft 1 at a predetermined rotation angle when it is not necessary to slow down the rotation of the railway vehicle's wheels 29, and loosens the hold on the brake shaft 1 when it is necessary to slow down the rotation of the wheels 29, and a first support part 10 which is connected to the braking part 2 and rotatably supports the brake shaft 1 The railway vehicle safety brake 100 is made compact because it includes a braking coil spring 19 supported by the first support portion 10 and pressing against the first support portion 10 when the rotation of the wheel 29 is not to be decelerated, a second support portion 14 that supports the braking coil spring 19 at a position opposite to the first support portion 10, and a linear motion portion 17 in which at least a part in the axial direction is enclosed within the braking coil spring 19, contacts the screw of the braking shaft 1, and is connected to the second support portion 14, causing the second support portion 14 to move linearly toward the wheel 29 and decelerating the rotation of the wheel 29.

[0037] Although an example using an excitation-type electromagnetic brake as the braking unit 2 has been described, a rotating machine that applies rotational torque or holding torque to the braking shaft 1 may also be used. The rotating machine is, for example, a motor. By using a rotating machine in the braking unit 2 and monotonically decreasing the rotational torque applied to the rotating braking shaft 1, the railway vehicle safety brake 100 can bring the linear motion unit 17 into contact with the wheel 29 gradually, thereby avoiding abrupt deceleration of the wheel 29 and, consequently, abrupt deceleration of the railway vehicle. Furthermore, when decelerating the rotation of the wheel 29, or when not decelerating the rotation of the wheel 29, the braking unit 2 can accelerate the rotation of the braking shaft 1 by applying rotational torque in the opposite direction to the holding torque applied to the braking shaft 1. This allows the linear motion unit 17 to move rapidly in a straight line until just before contacting the wheel 29, and then gradually bring the linear motion unit 17 into contact with the wheel 29.

[0038] Furthermore, the boundary between the first brake shaft portion 1A and the second brake shaft portion 1B, i.e., the step, catches on the first support portion 10, and the first support portion 10 supports the brake shaft 1 in the axial direction, thus enabling a configuration in which the brake shaft 1 does not move toward the wheel 29 with a simple structure.

[0039] Furthermore, by having the bearing 24 enclosed and fixed within the first support portion 10, and by having the pressing force generated by the braking coil spring 19 applied to the bearing 24 via the braking shaft 1, the rotation of the braking shaft 1 can be stabilized.

[0040] Furthermore, the cylindrical portion 13 included in the first support portion 10 can alleviate the bending load applied to the braking shaft 1 when the brake shoe 28 is pressed against the wheel 29, thereby reducing the risk of the braking shaft 1 breaking.

[0041] Furthermore, since the number of parts that slide and wear down during the linear motion of the linear motion unit 17 can be reduced, maintenance such as parts replacement can be easily performed.

[0042] Furthermore, while an example was described in which the railway vehicle safety brake 100 activates to decelerate the rotation of the wheels 29 when the service brake is unable to operate, the railway vehicle safety brake 100 may also activate to decelerate the rotation of the wheels 29 when the service brake is operating and decelerating the rotation of the wheels 29.

[0043] Further, the internal thread formed on the inner circumference of the linear motion part 17 is a ball screw in which a plurality of first balls are arranged on the thread part. The fixing part 11 is a ball spline nut that encloses the balls and the ball circulation part 22. By doing so, the frictional resistance generated by the rotation of the brake shaft 1 and the linear motion of the linear motion part 17 can be reduced. Since the rotational motion of the linear motion part 17 and the second support part 14 can be restricted by the ball spline nut, the torque for twisting the brake coil spring 19 can be suppressed, and performance deterioration can be suppressed. Also, by suppressing the movement of the brake wheel 28 in the rotational direction, unnecessary sliding between the contact surface with the wheel 29 can be prevented.

[0044] Further, a pressing force transmission part 16 is provided from the second flange part 15 in the expansion and contraction direction of the brake transmission spring 4. By excluding the parts unnecessary for the transmission of the pressing force, the second support part 14 can be lightened, and maintenance such as disassembling the brake can be easily performed.

[0045] Also, by using the brake part 2 whose braking of the brake shaft 1 is released when de-energized, the railway vehicle safety brake 100 can operate automatically when the power supply of the vehicle is lost.

[0046] Embodiment 2. The railway vehicle safety brake 100 according to Embodiment 2 will be described with reference to FIG. 11. In Embodiment 1, the railway vehicle safety brake 100 in which the brake shaft is screwed into the inner diameter part of the hollow linear motion part has been described. However, in Embodiment 2, the difference is that the linear motion part is screwed into the hollow brake shaft. The following will focus on the differences from Embodiment 1, and the description of the same or corresponding parts will be omitted as appropriate.

[0047] Hereinafter, an example in which the brake part 2 is an electromagnetic brake of the excitation type will be described. Similar to Embodiment 1, when the brake part 2 is in the non-excited state, the brake transmission part 3, the brake transmission spring 4, and the armature 9 rotate together with the brake shaft 1. Hereinafter, the brake transmission part 3, the brake transmission spring 4, and the armature 9 will be collectively referred to as the rotating part.

[0048] Figure 11 shows the case where the safety brake 100 for railway vehicles using a friction - type excited electromagnetic brake is in the non - excited state. The brake shaft 1 of the safety brake 100 for railway vehicles according to the present embodiment is a hollow shaft having a shaft portion 1d and a third flange portion 1e. The shaft portion 1d is inserted into the through - hole of the brake transmission portion 3. The third flange portion 1e is provided in a direction intersecting the axial length direction, for example, in a perpendicular direction, at the end on the side opposite to the wheel side in the axial length direction. The brake shaft has a female screw portion provided in the axial length direction on the inner diameter surface and is fixed to the rotating portion of the brake portion 2 via the third flange portion 1e.

[0049] By bolt - fixing the third flange portion 1e and the brake transmission portion 3, the brake shaft 1 is fixed to the brake transmission portion 3. Also, key grooves (not shown) are formed in the brake shaft 1 and the brake transmission portion 3, and the brake shaft 1 and the brake transmission portion 3 may be fixed by fitting a key into the key grooves of the brake shaft 1 and the brake transmission portion 3. Thus (Fig. 11), the brake transmission portion 3, the brake transmission spring 4, and the armature 5 and the brake shaft 1 are fixed.

[0050] The linear motion portion 17 has a male screw portion 17a in a range of a predetermined length from the end on the side opposite to the wheel 29 side. The range of a predetermined length from the end is a length range greater than the distance from the fixed position of the brake wheel 28 connected to the end on the wheel 29 side of the second support portion to the wheel 29.

[0051] The male screw portion 17a of the linear motion portion 17 is screwed into the female screw portion of the brake shaft 1. The male screw portion of the linear motion portion 17 and the female screw portion of the brake shaft 17 are a sliding screw. When the linear motion portion 17 moves linearly toward the wheel 29 by the female screw portion of the brake shaft 1 and the male screw portion 17a of the linear motion portion 17, the brake shaft 1 and the rotating portion perform a rotational motion.

[0052] As shown in Fig. 11, when the linear motion portion 17 is fixed by the fixing portion 11 so as not to rotate around the axial length direction as the rotation axis, the brake coil spring 19 pushes the second flange portion 15 in the direction of the wheel 29, and the linear motion portion 17 performs only linear motion without rotating.

[0053] When the braking unit 2 is de-energized, the magnetic field disappears, and the force pressing the abutment 5 against the friction member 6 by the magnetic field is removed. However, the force exerted by the braking coil spring 19 pushing the second flange portion 15 toward the wheel 29 pulls the linear motion portion 17 and the rotating portion toward the wheel 29. Therefore, even in the de-energized state, the abutment 4 of the rotating portion may come into contact with the friction member 6 while rotating, as shown in the example in Figure 11. The case described above is when there is no gap between the abutment 4 and the friction member 6 and they are in contact when de-energized, but the rotating portion may rotate together with the braking shaft 1 even when the abutment 5 and the friction member 6 are separated.

[0054] The operation of the railway vehicle safety brake according to this embodiment will now be described. When the braking unit is in an unexcited state, the railway vehicle safety brake decelerates the rotation of the wheel 29. In this case, the braking unit 2 loosens its hold on the rotation direction of the rotating unit, thereby making the braking shaft 1 rotatable. The rotatable braking shaft 1 also enables the linear motion of the linear motion unit 17, and the force of the braking coil spring 19 can propel the linear motion unit 17 toward the wheel 29. That is, the force of the braking coil spring 19 pushing toward the wheel 29 allows the second support unit 14 connected to the linear motion unit 17 to move linearly toward the wheel 29.

[0055] In this way, by providing the braking shaft 1 outside the braking coil spring 19, it is possible to reduce the size of the linear motion section 17 in the direction intersecting the axial length, thereby reducing the diameter of the braking coil spring 19. In other words, the size of the railway vehicle safety brake 100 can be further miniaturized. Furthermore, in this embodiment, by using sliding screws for the male threaded portion 17a of the linear motion section 17 and the female threaded portion of the braking shaft 1, component costs can be reduced compared to the case where a ball screw is used. Moreover, when the braking section 2 is energized, the static friction force that hinders the rotational movement of the male threaded portion 17a of the linear motion section 17 and the female threaded portion of the braking shaft 1 is higher than in the case of a ball screw, making it possible to maintain the rotation angle of the braking shaft 1 at a predetermined angle, thereby stopping the linear motion of the linear motion section 17.

[0056] Embodiment 3. A railway vehicle safety brake 100 according to Embodiment 3 will be described with reference to Figures 12 to 14. In Embodiment 1, a railway vehicle safety brake 100 that suppresses the rotation of the braking shaft 1 by static friction force was described, but in Embodiment 3, the first teeth 30 formed on the axle 5 and the second teeth 31 provided on the brake stator 9 mesh together to suppress the rotation of the braking shaft 1. The following will mainly describe the differences from Embodiment 1, and descriptions of the same or corresponding parts will be omitted as appropriate.

[0057] Figure 12 is a schematic cross-sectional view showing the braking section 2 of the railway vehicle safety brake 100 according to Embodiment 3 in an excited state. As shown in Figure 12, the braking section 2 is an excitation-type tooth brake and consists of a braking transmission section 3 having first teeth 30 into which the braking shaft 1 is inserted and fixed, and a brake stator 9 that provides the braking force to the braking shaft 1 to the braking transmission section 3. Figure 13 is an enlarged schematic perspective view showing the meshed first teeth 30 and second teeth 31 in Figure 12. The dynamic transmission section consists of a braking transmission spring 4 and an axle 5 connected to the braking transmission spring 4 and having the first teeth 30 formed on it, and the brake stator 9 consists of a winding coil 7 arranged opposite to the first teeth 30 via a second tooth 31 that meshes with the first teeth 30. The braking transmission spring 4 is attached to a support bolt 32, and the axle 5 and the braking transmission section 3 are fixed together.

[0058] Figure 14 is a schematic cross-sectional view showing the case when the braking unit 2 of the railway vehicle safety brake 100 according to Embodiment 3 is in an unenergized state. When the winding coil 7 is energized, the first tooth 30 and the second tooth 31 mesh together, and when de-energized, the first tooth 30 separates from the second tooth 31, allowing the braking transmission unit 3, armature 5, and braking transmission spring 4 to rotate together with the braking shaft 1. When the braking unit 2 is unenergized, a gap is formed between the first tooth 30 and the second tooth 31 so that they do not interfere with each other. Because the first tooth 30 and the second tooth 31 do not interfere with each other, the braking shaft 1 becomes rotatable, and the linear motion unit 17 can move linearly toward the wheel 29.

[0059] Thus, in the railway vehicle safety brake 100 according to Embodiment 3, the first tooth 30 and the second tooth 31 mesh together when energized, generating a large force to suppress the rotation of the brake shaft 1, and thus suppressing the rotation of the brake shaft 1 caused by a greater pressing force generated by the brake coil spring 19.

[0060] Embodiment 4. The railway vehicle safety brake 100 according to Embodiment 4 will be described with reference to Figure 15. In Embodiment 1, an example in which the railway vehicle safety brake 100 is used alone was described, but in Embodiment 4, the difference is that the service brake 26 and the railway vehicle safety brake 100 are facing each other with the wheel 29 in between. The following description will focus on the differences from Embodiment 1, and descriptions of the same or corresponding parts will be omitted as appropriate.

[0061] Figure 15 shows an example in which the railway vehicle safety brake 100 according to Embodiment 3 is installed adjacent to the service brake 26 in the horizontal direction. As shown in Figure 15, the railway vehicle safety brake 100 is positioned adjacent to the service brake 26, which operates the brake shoe 28 using high-pressure air. The power source for the service brake 26 to which the railway vehicle safety brake 100 is attached may be electricity or the like, in addition to the high-pressure air mentioned above. The second support part 14 has a retaining rod 27 at its tip on the wheel 29 side and is integrated with the retaining rod 27 of the service brake 26, and they are used in common. The retaining rod 27 transmits the pressing force from the braking transmission spring 4 received from the second support part 14 to the brake shoe 28, and the brake shoe 28 is pressed against the wheel 29, so the rotation of the wheel 29 is reduced. Here, the retaining rod 27 shown in Figure 10 has a step in the axial direction, but the presence or absence of the step is not required. The brake shoe 28 is attached to the tip of the retaining rod 27.

[0062] If the power supply, such as high-pressure air, to the service brake 26 is interrupted, the service brake 26 cannot operate, the excitation of the braking unit 2 is released, and the braking shaft 1 becomes rotatable. The linear motion unit 17 attached to the second support unit 14 moves linearly toward the wheel 29, pressing the brake shoe 28 against the wheel 29 and decelerating the rotation of the wheel 29. Alternatively, regardless of whether the service brake 26 has lost power, the linear motion unit 17 attached to the second support unit 14 may move linearly toward the wheel 29 if the braking unit 2 receives an electrical signal to release the excitation.

[0063] As described above, the railway vehicle safety brake 100 according to Embodiment 4 is installed adjacent to the service brake 26 in the horizontal direction, so that the space around the wheel 29 can be effectively utilized.

[0064] Embodiment 5. The railway vehicle safety brake 100 according to Embodiment 5 will be described with reference to Figure 16. In Embodiment 1, the braking unit 2 was described as suppressing the rotation of the braking shaft 1, but in Embodiment 5, the braking unit 2 also has a power generation function, which is a difference. The following will mainly describe the differences from Embodiment 1, and descriptions of the same or corresponding parts will be omitted as appropriate.

[0065] The braking unit 2 includes a plurality of stators 35, a rotor 34 attached to the braking shaft 1 and rotating around the braking shaft 1, and a stator support unit 33 that supports the stators 35, and has a generator that generates electricity from the axial magnetic flux caused by the rotation of the braking shaft 1. The generator is, for example, an axial gap motor. It may further include a power storage unit for storing the generated electricity.

[0066] The stator support portion 33 is fixed with one surface in contact with the first support portion 10 and the other surface in contact with the coil case 8. The stator support portion 33 has a through hole formed perpendicular to the surface in contact with the first support portion 10, and a plurality of disc-shaped stators 35 are fixed to the inner circumference of the through hole, and the braking shaft 1 is inserted and positioned so as not to touch the stators 35. A disc-shaped rotor 34 is attached to the braking shaft 1, and the rotor 34 is positioned with a predetermined gap between it and the plurality of stators 35.

[0067] When the braking unit 2 is de-energized, the rotor 34 rotates together with the braking shaft 1. The rotation of the braking shaft 1 is used as input to operate the generator, converting the kinetic energy from the rotation into electrical energy and storing it. Using the stored electricity, the generator rotates, causing the linear motion unit 17 to which the second support unit 14 is attached to move linearly away from the wheel 29, and thus the brake shoe 28 moves away from the wheel 29.

[0068] Thus, the railway vehicle safety brake 100 according to Embodiment 5 can release the action of the brake shoe 28 pressing against the wheel 29 by using the electricity generated by a generator that converts the kinetic energy due to the rotation when the linear motion unit 17 moves linearly toward the wheel 29 into electrical energy, thereby rotating the brake shaft 1 to which the rotor 34 of the generator is attached.

[0069] While this disclosure describes various exemplary embodiments, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the art disclosed herein. For example, these include modifying, adding, or omitting at least one component, or even extracting at least one component and combining it with a component from another embodiment.

[0070] 1 Brake shaft, 1A First brake shaft section, 1B Second brake shaft section, 1C Third brake shaft section, 2 Brake section, 3 Brake transmission section, 4 Brake transmission spring, 5 Affix, 6 Friction member, 7 Winding coil, 8 Coil case, 9 Brake stator, 10 First support section, 11 Fixing section, 12 First flange section, 13 Cylindrical section, 14 Second support section, 15 Second flange section, 16 Pressing force transmission section, 17 Linear motion section, 18 Projection, 19 Brake coil spring, 20 Transfer groove, 21 Second ball, 22 Ball circulation section, 23 Brake cover, 24 Bearing, 25 Retaining plate, 26 Service brake, 27 Retaining rod, 28 Brake shoe, 29 Wheel, 30 First tooth, 31 Second tooth, 32 Support bolt, 33 Stator support section, 34 Rotor, 35 stator

Claims

1. A safety brake for a railway vehicle comprising: a brake shaft having a thread formed on at least a portion of it; a braking part provided at one end of the brake shaft, which holds the brake shaft at a predetermined rotation angle when the rotation of the wheel of the railway vehicle is not to be reduced, and loosens the hold on the brake shaft when the rotation of the wheel is to be reduced; a first support part connected to the braking part and rotatably supporting the brake shaft; a brake coil spring supported by the first support part and pressing against the first support part when the rotation of the wheel is not to be reduced; a second support part supporting the brake coil spring at a position opposite the first support part; and a linear motion part, in which at least a portion in the axial direction is enclosed within the brake coil spring, contacts the thread on the brake shaft, and is connected to the second support part, which moves the second support part linearly toward the wheel and reduces the rotation of the wheel.

2. The safety brake for a railway vehicle according to claim 1, wherein the braking unit is an electromagnetic brake that is energized when the rotation of the wheel is not decelerated to maintain the rotation of the braking shaft at a predetermined rotation angle, and the energization is released when the rotation of the wheel is decelerated to loosen the hold on the braking shaft.

3. The safety brake for a railway vehicle according to claim 1, wherein the braking unit is a rotating machine that applies rotational torque to the braking shaft, and when the rotation of the wheel is decelerated, the rotational torque applied to the braking shaft is monotonically reduced, thereby causing the linear motion unit to come into gentle contact with the wheel.

4. The safety brake for a railway vehicle according to claim 1, wherein the braking unit is a rotating machine that applies rotational torque or holding torque to the braking shaft, and when decelerating the rotation of the wheel, it applies rotational torque in the opposite direction to the holding torque applied when the rotation of the wheel is not decelerated.

5. The safety brake for a railway vehicle according to claim 1, wherein the braking shaft has a first braking shaft portion enclosed within the braking section and a second braking shaft portion connected to the first braking shaft portion and enclosed within the first support portion, and the surface of the first braking shaft portion perpendicular to the axial direction is pressed against the first support portion and supported in the axial direction by a step created by making the diameter of the first braking shaft portion larger than the diameter of the second braking shaft portion, and when the braking section is in an unexcited state, the surface perpendicular to the axial direction at the step and the first support portion slide against each other.

6. The safety brake for a railway vehicle according to claim 1, wherein the brake shaft has a first brake shaft portion enclosed within the brake section and a second brake shaft portion enclosed within the first support portion, and the surface of the first brake shaft portion perpendicular to the axial direction is pressed against the first support portion and supported in the axial direction by a step created by making the diameter of the first brake shaft portion larger than the diameter of the second brake shaft portion, the first support portion encloses a bearing, and when the brake section is in an unexcited state, the surface of the step perpendicular to the axial direction contacts the inner ring of the bearing as the brake shaft rotates.

7. The safety brake for railway vehicles according to any one of claims 1 to 6, wherein the first support portion supports the outer circumference of the linear motion portion and is composed of a cylindrical portion having an outer diameter smaller than the outer diameter of the second support portion and a first flange portion having an outer diameter larger than the cylindrical portion, and the first flange portion supports one end of the braking coil spring.

8. The railway vehicle safety brake according to claim 7, wherein the first support portion further supports the outer circumference of the linear motion portion and comprises a cylindrical fixing portion having a flange surface and having an outer diameter smaller than the outer diameter of the second support portion, the cylindrical portion is pressed against the flange surface of the fixing portion and supports the outer circumference of the linear motion portion via the fixing portion.

9. A safety brake for a railway vehicle according to claim 7 or 8, wherein a plurality of first balls are arranged on the threads of an inner circumference screw on the inner circumference of the linear motion part, the screw of the braking shaft is in contact with the first balls, and the first support part has a second ball that suppresses the rotational motion of the linear motion part that attempts to rotate together with the braking shaft which is rotated by the first balls, and a ball circulation part that circulates the second ball, and guides the linear motion of the linear motion part.

10. The safety brake for a railway vehicle according to claim 9, wherein the internal circumferential screw adjusts the speed of the linear motion of the linear motion part toward the wheel.

11. The safety brake for a railway vehicle according to any one of claims 1 to 10, wherein the second support portion comprises a cylindrical second flange portion that supports a part of the outer circumference of the linear motion portion, and a pressing force transmission portion integrated with the second flange portion that transmits pressing force in the direction of the wheel.

12. The safety brake for a railway vehicle according to claim 2, wherein the braking unit comprises a braking transmission unit that transmits braking force to the braking shaft, a braking transmission spring fixed to the braking transmission unit, an abutment attached to the braking transmission spring, and a winding coil positioned opposite the abutment via a friction member, wherein when the winding coil is energized, the friction member and the abutment are in contact, and when the winding coil is de-energized, the abutment separates from the friction member, and the braking transmission unit, the abutment, and the braking transmission spring rotate together with the braking shaft.

13. The safety brake for a railway vehicle according to claim 2, wherein the braking unit comprises a braking transmission unit that transmits braking force to the braking shaft, a braking transmission spring provided within the braking transmission unit, an armature connected to the braking transmission spring and having a first tooth formed thereon, and a winding coil positioned opposite the armature via a second tooth that meshes with the first tooth, wherein when the winding coil is energized, the first tooth and the second tooth mesh, and when the winding coil is de-energized, the first tooth separates from the second tooth, and the braking transmission unit, the armature, and the braking transmission spring rotate together with the braking shaft.

14. The safety brake for a railway vehicle according to claim 1, wherein the braking unit has a rotating unit that can rotate in the same direction as the braking shaft when decelerating the rotation of the wheel, the braking shaft is a hollow shaft having a third flange portion formed in a direction intersecting the axial direction at the end opposite to the wheel side in the axial direction, and has an internal thread portion in the axial direction of its inner diameter surface, and is fixed to the rotating unit via the third flange portion, and the linear unit has an external thread portion in a range of a predetermined length from the end opposite to the wheel side, and is screwed into the internal thread portion via the external thread portion.

15. A safety brake for a railway vehicle according to any one of claims 1 to 14, provided horizontally adjacent to a service brake and sharing brake shoes with the service brake.

16. The safety brake for a railway vehicle according to any one of claims 1 to 15, wherein the braking unit comprises a plurality of stators, a rotor attached to the braking shaft and rotating about the braking shaft, and a stator support unit that fixes the plurality of stators inside, and is provided with a generator that generates electricity from the axial magnetic flux caused by the rotation of the braking shaft, the rotor is arranged between the plurality of stators, and the stator support unit is fixed in contact with the first support unit.

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