ACTUATOR, ACTUATOR FOR VEHICLE TILTING AND VEHICLE TILTING SYSTEM

Abstract

To achieve improvement of power transmission efficiency, responsiveness, and accuracy and achieve energy saving when an inclination of a vehicle body is maintained.SOLUTION: One embodiment of an actuator includes: a motor; a rotary part into which rotational force from the motor is input; a linear motion part which is connected to the rotary part through a ball screw and linearly moves along the ball screw in conjunction with rotation of the rotary part; and a shield part which is incorporated into the rotary part, transmits rotational force from the motor side to the ball screw side, and blocks rotational force from the ball screw side to stop rotation.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an actuator, a vehicle body tilt actuator, and a vehicle body tilt system. [Background technology]

[0002] Electric actuators for carbody tilting and carbody tilting systems have been proposed to improve the ride comfort of railway vehicles traveling at high speeds on curved sections (see, for example, Patent Document 1 and Patent Document 2). Carbody tilting systems tilt and return the carbody by controlling actuators installed between the bogie and the carbody, such as pendulum-type carbody tilting devices and air spring-type carbody tilting devices. Hydraulic actuators are the mainstream actuators in conventional carbody tilting systems. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-29039 [Patent Document 2] JP 2011-025751 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, a vehicle body tilting system using hydraulic actuators has low responsiveness and precision, which may affect the ride comfort. In addition, in the case of hydraulic actuators, the system that drives the actuator (hydraulic and hydraulic system) is large, and a large space is required for installation.

[0005] For this reason, it is conceivable to adopt a sliding screw type electric actuator for the car body tilting system. Although an electric actuator is preferable because it requires a small installation space, a car body tilting system using a sliding screw type actuator may affect the ride comfort due to a decrease in power transmission efficiency. In addition, a car body tilting system using an electric actuator is also concerned about the constant consumption of electricity when maintaining the tilt of the car body, resulting in energy waste. Therefore, an object of the present invention is to improve power transmission efficiency, responsiveness, and accuracy, while also saving energy when maintaining the tilt of the vehicle body. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the actuator of the present invention includes a motor, a rotating unit to which a rotational force from the motor is input, a linear motion unit connected to the rotating unit via a ball screw and moving linearly along the ball screw as the rotating unit rotates, and a blocking unit incorporated in the rotating unit, transmitting the rotational force from the motor side to the ball screw side and blocking the rotational force from the ball screw side to stop the rotation.

[0007] Such actuators improve power transmission efficiency, responsiveness, and precision by using ball screws, and their use for tilting the vehicle body contributes to energy savings when maintaining the vehicle body tilt. Furthermore, such actuators are applicable to a wide range of fields other than vehicle body tilting as they are capable of driving with high responsiveness and precision while isolating the effects of external forces.

[0008] In order to solve the above problems, one aspect of the actuator for vehicle body tilting according to the present invention includes a motor, a rotating unit to which rotational force from the motor is input, a linear motion unit connected to the rotating unit via a ball screw and changing the tilt of the vehicle body by moving linearly along the ball screw as the rotating unit rotates, and a blocking unit incorporated in the rotating unit, transmitting the rotational force from the motor side to the ball screw side and blocking the rotational force from the ball screw side to stop the rotation.

[0009] This type of vehicle body tilt actuator uses a ball screw, which improves power transmission efficiency, responsiveness, and accuracy, and has a compact configuration with a small installation space. In addition, when maintaining tilt, the rotation of the rotating part can be stopped at the cut-off part even without the driving force of the motor, which saves energy. Although the transmission of external force from the linear part to the rotating part increases with the improvement in power transmission efficiency due to the use of a ball screw, the advantage of using a ball screw becomes apparent because the external force transmission is stopped by the cut-off part.

[0010] In addition, in the vehicle body tilt actuator, it is preferable that the cutoff unit functions only by a mechanical mechanism. For example, an electromagnetic clutch can be used as the cutoff unit, but if it is mechanical, no power consumption is required to maintain the tilt of the vehicle body, which is particularly energy-saving. Furthermore, the use of a mechanical cutoff unit simplifies the configuration of the vehicle body tilt actuator, and further space saving is achieved.

[0011] Furthermore, in the case where the vehicle body tilt actuator further includes a speed reducer that is incorporated in the rotating part and reduces the rotation speed, the cutoff part may be provided between the speed reducer and the ball screw, or between the motor and the speed reducer. For example, when the load torque in the vehicle body tilt actuator is large or when the output torque (thrust) of the vehicle body tilt actuator is large, it is preferable that the cutoff part be provided between the motor and the speed reducer. Furthermore, in the case where the response of the cutoff part to stop rotation is improved or noise is reduced, it is preferable that the cutoff part be provided between the speed reducer and the ball screw.

[0012] In order to solve the above problems, the vehicle body tilting system of the present invention is a vehicle body tilting system comprising an actuator that changes the inclination of the vehicle body, and a control unit that controls the inclination of the vehicle body by controlling the actuator, wherein the actuator comprises the motor, the rotating unit, the linear motion unit, and the blocking unit. Such a vehicle body tilting system not only improves power transmission efficiency, responsiveness, and accuracy, but also saves energy when maintaining the vehicle body tilted.

[0013] In the vehicle body tilting system, it is preferable that the control unit stops driving the motor when maintaining the tilt of the vehicle body. By stopping the driving of the motor, the function of the cutoff unit is significantly utilized, thereby achieving excellent energy saving. Effect of the Invention

[0014] According to the present invention, it is possible to improve power transmission efficiency, responsiveness, and accuracy, and also to save energy when maintaining the tilt of the vehicle body. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a functional block diagram showing a railway vehicle incorporating an embodiment of a carbody tilting system according to the present invention. [Diagram 2] 1 is a structural conceptual diagram showing a railway vehicle incorporating an embodiment of a carbody tilting system of the present invention. FIG. [Diagram 3] FIG. 2 is a cross-sectional view showing the structure of an electric actuator. [Figure 4] FIG. [Diagram 5] 11A and 11B are diagrams illustrating the operation of the reverse input cutoff clutch when a rotational force (rotational torque) is input from the input member side. [Figure 6] 11A and 11B are diagrams illustrating the operation of the reverse input cutoff clutch when a rotational force (rotational torque) is input from the output member side. [Figure 7] 13A and 13B are diagrams illustrating an electric actuator according to another embodiment. [Figure 8] FIG. 13 is a diagram showing a schematic diagram of a railway vehicle incorporating a modified carbody tilting system. [Figure 9] FIG. 11 is a diagram showing a second specific example of vehicle body tilt control. [Figure 10] FIG. 11 is a diagram showing a third specific example of vehicle body tilt control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, in order to avoid the following description becoming unnecessarily redundant and to facilitate understanding by those skilled in the art, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters and duplicated description of substantially the same configuration may be omitted. In addition, elements shown in the previously described figures may be appropriately referenced in the description of the later figures.

[0017] 1 and 2 are diagrams showing a railway vehicle incorporating an embodiment of a carbody tilting system of the present invention. Fig. 1 shows a functional block diagram, and Fig. 2 shows a conceptual structural diagram.

[0018] The railway vehicle 1 has a carbody 100 and a bogie 200, and a carbody tilting system 300 of this embodiment is provided between the carbody 100 and the bogie 200. Any type of carbody tilting system 300 may be adopted, such as a controlled natural pendulum type, a forced carbody tilting type, an air spring type with an actuator, or a hybrid carbody tilting system that combines the pendulum type and the air spring type. This carbody tilting system 300 corresponds to one embodiment of the carbody tilting system of the present invention.

[0019] The vehicle body tilt system 300 includes a vehicle body tilt mechanism 310 , an ECU (Electronic Control Unit) 320 , a vehicle body tilt control device 330 , and a sensor 340 .

[0020] The car body tilt mechanism 310 is a mechanism that changes and maintains the tilt of the car body 100 relative to the bogie 200 by means of an electric actuator 350. As the sensor 340, for example, an acceleration sensor, a gyro sensor, and a speed sensor are mainly used.

[0021] The carbody tilt control device 330 calculates a desired inclination of the carbody 100 based on running information of the railway vehicle 1 obtained by the sensor 340, and issues a command to an ECU (Electronic Control Unit) 320 to achieve such carbody inclination. The ECU 320 controls a motor (not shown) of an electric actuator 350 to drive the carbody tilt mechanism 310, thereby achieving the desired carbody inclination. The carbody inclination control device 330 corresponds to an example of a control unit referred to in the present invention that controls the electric actuator 350 to control the inclination of the carbody.

[0022] A reverse input cutoff clutch 360 is incorporated in the electric actuator 350, and as will be described in detail later, energy saving is achieved in maintaining the inclination of the vehicle body 100. The electric actuator 350 corresponds to one embodiment of the vehicle body inclination actuator of the present invention. The detailed structure of the electric actuator 350 will be described below.

[0023] Fig. 3 is a cross-sectional view showing the structure of the electric actuator 350. Fig. 3 shows a cross-sectional view cut along a plane along the center of the output shaft of the electric actuator 350. For ease of understanding, the appearance of some elements is shown instead of a cross-section.

[0024] The electric actuator 350 of this embodiment is a ball screw type linear actuator that utilizes a ball screw to convert rotational motion into linear motion, converting the rotational force input from the motor into axial force (force in the direction along the axis) and outputting it.

[0025] The electric actuator 350 of this embodiment includes a ball screw 10, a transmission gear 20, an input side rotating shaft 22, an output shaft 30, a housing member 40, a ball bearing 51, a bearing housing 50, a reverse input cut-off clutch 360, and a motor and a reducer (not shown).

[0026] The transmission gear 20 is fixed to an input side rotating shaft 22 by a gear fixing nut 21. The transmission gear 20 receives a rotational force from a motor via a reducer and transmits it to the input side rotating shaft 22.

[0027] The reverse input cutoff clutch 360 transmits the rotational force of the input side rotating shaft 22 to the screw shaft 11 of the ball screw 10. The ball screw 10 converts the rotational motion due to the rotational force transmitted via the reverse input cutoff clutch 360 into linear motion.

[0028] The output shaft 30 is connected to the nut 13 of the ball screw 10, and outputs the axial force converted from the rotational force by the ball screw 10. The axial force output by the output shaft 30 is transmitted to the vehicle body 100 shown in FIG. 2, and the inclination of the vehicle body 100 is changed. The housing member 40 is a substantially cylindrical member that houses the ball screw 10 and the output shaft 30 , and holds the electric actuator 350 in its entirety.

[0029] The ball bearing 51 rotatably holds the screw shaft 11 of the ball screw 10 and the input side rotating shaft 22. The bearing housing 50 fixes the ball bearing 51 to the housing member 40. A reverse input cutoff clutch 360 is also incorporated in the bearing housing 50.

[0030] The portion from the reducer to the screw shaft 11 of the ball screw 10 that is rotated by the motor corresponds to an example of the rotating part according to the present invention, and the output shaft 30 corresponds to an example of the linear motion part according to the present invention.

[0031] The ball screw 10 comprises a screw shaft 11 having a helical screw groove 11a on its outer surface, a nut 13 having a helical screw groove 13a on its inner surface that faces the screw groove 11a of the screw shaft 11, a plurality of balls (not shown) loaded so as to be able to roll within a helical ball rolling path formed by both screw grooves 11a, 13a, and a ball circulation path (not shown) that circulates the balls from the end point of the ball rolling path back to the starting point.

[0032] The balls move within the ball rolling path, rotate around the screw shaft 11, and reach the end point of the ball rolling path, where they are picked up from the ball rolling path and enter one end of the ball circulating path. The balls that have entered the ball rolling path pass through the ball circulating path and reach the other end of the ball circulating path, from which they are returned to the start point of the ball rolling path.

[0033] The materials of the screw shaft 11, the nut 13, and the balls are not particularly limited, and general materials can be used, for example, metals such as steel, ceramics, etc. The cross-sectional shape of the screw grooves 11a, 13a may be a circular arc or a gothic arc.

[0034] In the ball screw 10, when the nut 13 and the screw shaft 1, which are indirectly engaged via the balls, are rotated relative to each other, the screw shaft 11 and the nut 13 move linearly relative to each other in the axial direction via the rolling of the balls. An endless ball passage is formed by the ball rolling path and the ball circulation path, and the balls rolling in the ball rolling path circulate endlessly in the endless ball passage, so that the screw shaft 11 and the nut 13 can move linearly continuously. The direction of linear movement of the nut 13 is determined by the direction of rotation of the screw shaft 11.

[0035] The nut 13 is connected to the output shaft 30 by a connecting element 53. In the present embodiment, as an example, two connecting elements 53 are provided. When the nut 13 moves linearly, the axial force is transmitted to the output shaft 30 by the connecting element 53, and the output shaft 30 moves linearly together with the nut 13, so that the axial force is output from the output shaft 30.

[0036] The ball screw 10 has excellent power transmission efficiency, responsiveness, and accuracy, and 90% or more of the rotational force input to the screw shaft 11 is output as linear movement of the output shaft 30. Conversely, when an external force is applied to the output shaft 30, a high proportion of the force is transmitted to the screw shaft 11 as rotation. In order to maintain the inclination of the vehicle body, it is necessary to stop the rotation of the screw shaft 11 transmitted from the external force in this manner, and stopping the rotation by the driving force of the motor would result in a waste of energy.

[0037] Therefore, in the electric actuator 350, a reverse input cutoff clutch 360 that stops the rotation by cutting off the rotational force transmitted from the screw shaft 11 side to the motor side is incorporated in the rotating part extending from the reducer to the screw shaft 11. In the example shown in Fig. 3, the reverse input cutoff clutch 360 is incorporated between the screw shaft 11 of the ball screw 10 and the input side rotating shaft 22.

[0038] The reverse input cutoff clutch 360 transmits the rotational force from the input side rotating shaft 22 to the screw shaft 11 for both left and right rotations, and cuts off the rotational force from the screw shaft 11 for both left and right rotations to stop the rotation. The reverse input cutoff clutch 360 eliminates the need to drive the motor when maintaining the vehicle body inclination, thereby saving energy. In addition, the electric actuator 350 equipped with the reverse input cutoff clutch 360 has a compact configuration and requires less installation space than a hydraulic actuator, thereby saving space. The reverse input cutoff clutch 360 corresponds to an example of the cutoff unit referred to in the present invention. FIG. 4 is an exploded perspective view of the reverse input cutoff clutch 360.

[0039] The reverse input cutoff clutch 360 is a locking type reverse input cutoff clutch, and includes an input member 362, an output member 363, a pressed member 364, a pair of engagement members 365a, 365b, and a biasing spring 366. The reverse input cutoff clutch 360 has a reverse input cutoff function of transmitting all of the rotational torque input to the input member 362 to the output member 363, while not transmitting the rotational torque reversely input to the output member 363 to the input member 362.

[0040] The input member 362 is integral with the input side rotation shaft 22 and receives the input of rotational torque. The input member 362 has a pair of input engagement protrusions 362a. Each of the pair of input engagement protrusions 362a has a generally elliptical cylindrical shape and extends in the axial direction from the input member 362. The pair of input engagement protrusions 362a are spaced apart from each other in the radial direction of the input member 362. In this specification and claims, unless otherwise specified, the axial direction refers to the axial direction of the input member 2, and the radial direction refers to the radial direction of the input member 2.

[0041] The output member 363 is integrated with the screw shaft 11 of the ball screw 10 and outputs a rotational torque. The output member 363 is disposed coaxially with the input member 362, and has an output engagement cam 363a.

[0042] The output engagement cam 363a is generally oval cylindrical and extends in the axial direction from the center of the output member 363. The distance from the rotation center of the output engagement cam 363a to the outer circumferential side surface is not constant in the circumferential direction, and the output engagement cam 363a is disposed in a portion between a pair of input engagement protrusions 362a. In addition, the output engagement cam 363a is formed with a guide hole 363b having a circular cross section, passing through the center of the output engagement cam 363a in the minor axis direction (diameter direction).

[0043] The biasing spring 366 is arranged inside the guide hole 363b without any rattle. The biasing spring 366 is a coil spring, and its entire length in a free state is greater than the width of the output engagement cam 366 in the minor axis direction.

[0044] The pressed member 364 is fixed integrally with the bearing housing 50, and its rotation is restricted (prevented). The pressed member 364 is arranged coaxially with the input member 362 and the output member 363, and radially outward of the input member 362 and the output member 363. Specifically, in the assembled state of the reverse input cutoff clutch 360, a pair of input engagement protrusions 362a and output engagement cam 363a are arranged radially inward of the pressed member 364. A pressed surface 364a, which is a cylindrical concave surface, is provided over the entire circumference of the inner circumferential surface of the pressed member 364.

[0045] The pair of engagement elements 365a, 365b are configured in a substantially semicircular plate shape (arch-shaped plate shape) and are disposed radially inside the pressed member 364. Specifically, the pair of engagement elements 365a, 365b are disposed so as to sandwich the output engagement cam 363a from both sides in the short axis direction. The pair of engagement elements 365a, 365b have outer circumferential side surfaces facing the pressed surface 364a, and have radially inner bottom surfaces engageable with the output engagement cam 363a.

[0046] A through hole that passes through the engaging elements 365a, 365b in the axial direction is provided in the radially intermediate portion of the pair of engaging elements 365a, 365b, and the input engaging protrusion 362a is inserted into the through hole.

[0047] When the input engaging protrusion 362a is inserted into the through holes of the engaging elements 365a, 365b, a gap exists between the input engaging protrusion 362a and the through holes. Therefore, the input engaging protrusion 362a is capable of moving relative to the engaging elements 365a, 365b in the rotational direction of the input member 362. A biasing force is applied to the pair of engaging elements 365a, 365b by a biasing spring 366 so as to move them away from each other. Next, the operation of the reverse input cutoff clutch 360 will be described. First, a case where a rotational torque is input from the input member 362 side will be described. FIG. 5 is a diagram showing the operation of the reverse input cutoff clutch 360 when a rotational force (rotational torque) is input from the input member 362 side.

[0048] When a rotational torque is input to the input member 362, the input engaging protrusion 362a rotates in the rotation direction of the input member 362 (clockwise in the example of FIG. 5) within the through holes of the engaging elements 365a, 365b, as shown in FIG. 5. Then, the radially inner surface of the input engaging protrusion 362a presses the inner surfaces of the engaging elements 365a, 365b radially inward, causing the pair of engaging elements 365a, 365b to move in a direction away from the pressed surface 364a against the force of the biasing spring 366.

[0049] As a result, the pair of engaging elements 365a, 365b move toward each other to sandwich the output engaging cam 363a from both radial sides. Therefore, the rotational torque input to the input member 362 is transmitted to the output member 363 via the pair of engaging elements 365a, 365b, and is output from the output member 363.

[0050] When a rotational torque is input to the input member 362, the reverse input cutoff clutch 360 moves the pair of engagement elements 365a, 365b in a direction away from the pressed surface 364a, regardless of the rotational direction of the input member 362. Then, the rotational torque input to the input member 362 is transmitted to the output member 363 via the pair of engagement elements 364a. Next, a case where a rotational torque is reversely input from the output member 363 side will be described. FIG. 6 is a diagram showing the operation of the reverse input cutoff clutch 360 when a rotational force (rotational torque) is input from the output member 363 side.

[0051] When a rotational torque is input in reverse to the output member 363, as shown in Fig. 6, the output engagement cam 363a rotates between the pair of engagement pieces 365a, 365b in the rotational direction of the output member 363 (clockwise in the example of Fig. 6). Then, both end portions of the output engagement cam 363a press the pair of engagement pieces 365a, 365b and move them away from each other. As a result, the outer surfaces of the pair of engagement pieces 365a, 365b are pressed against the pressed surface 364a. Then, the pair of engagement pieces 365a, 365b are pushed between the output engagement cam 363a and the pressed member 364, so that the rotation relative to the pressed member 364 is stopped, and the rotational torque is not transmitted to the input member 362 side.

[0052] When a rotational torque is reversely input to the output member 363, the reverse input cutoff clutch 360 moves the pair of engagement members 365a, 365b in directions approaching the pressed surface 364a, respectively, regardless of the rotational direction of the output member 363, thereby stopping the rotation.

[0053] 3, the electric actuator 350 transmits the rotational force transmitted from the motor to the input side rotating shaft 22 via the reducer and the transmission gear 20 to the screw shaft 11 of the ball screw 10. On the other hand, the electric actuator 350 uses the reverse input cutoff clutch 360 to cut off the rotational force input in reverse to the screw shaft 11 by an external force from the output shaft 30 side, thereby stopping the rotation. Therefore, since the reverse input rotational force is not transmitted to the transmission gear 20, the reducer, or the motor, there is no need to drive the motor to stop the rotation. In other words, the electric actuator 350 does not require the motor to be driven to maintain the inclination of the vehicle body 100, and energy saving is achieved.

[0054] 1, the vehicle body tilt control device 330 stops driving the motor via the ECU 320 when maintaining the tilt of the vehicle body 100. This allows the vehicle body tilt system 300 to achieve energy saving.

[0055] As the cutoff unit of the present invention, for example, an electromagnetic clutch may be used, but in this embodiment, as described above, a mechanical reverse input cutoff clutch 360 is used. Therefore, no power is required to stop the rotation, and further energy saving is achieved. In addition, by using the mechanical reverse input cutoff clutch 360, the configuration of the electric actuator 350 is simpler than when an electromagnetic clutch is used, and further space saving is achieved.

[0056] 3, the reverse input cutoff clutch 360 in the electric actuator 350 is provided between the reducer and the ball screw 10. When the reverse input cutoff clutch 360 is disposed in this manner, when a reverse input occurs, the rotational force is transmitted to the reverse input cutoff clutch 360 without passing through the reducer, improving the responsiveness of the rotation stop. In addition, when the reverse input cutoff clutch 360 is disposed in this manner, the effects of backlash and the like caused by the reducer are suppressed, reducing noise. Next, another embodiment in which the reverse input cutoff clutch 360 is disposed differently will be described. FIG. 7 is a diagram showing an electric actuator according to another embodiment. The electric actuator 400 shown in FIG. 7 is used in place of the electric actuator 350 shown in FIG. 3 in the vehicle body tilt system 300 shown in FIG. 1 and FIG.

[0057] FIG. 7 also illustrates the motor 410 and the reducer 420, which are not shown in FIG. 3, but the housing member 40, which is shown in FIG. 3, is not shown. The motor 410 is, for example, a servo motor, which corresponds to an example of the motor referred to in the present invention.

[0058] The reducer 420 has multiple gears 421, 422, 423, and the gears with different numbers of teeth mesh and rotate, thereby reducing the rotation speed on the transmission gear 20 side relative to the rotation speed on the motor 410 side. By reducing the rotation speed in this way, a rotation force (rotation torque) larger than the rotation force (rotation torque) on the motor 410 side is generated on the transmission gear 20 side. The reducer 420 corresponds to an example of the speed reduction section according to the present invention. As the speed reduction section according to the present invention, a belt type may be used instead of a gear type.

[0059] When the load torque in the electric actuator 400 is large or when the output torque (thrust) is large, a reducer 420 with a large reduction ratio is adopted, and the rotational force (rotational torque) on the transmission gear 20 side becomes particularly large relative to the rotational force (rotational torque) on the motor 410 side. For this reason, in the arrangement of the reverse input cutoff clutch 360 shown in Fig. 3, a large force is also applied to the reverse input cutoff clutch 360, and a large reverse input cutoff clutch 360 is required.

[0060] It is desirable to avoid making the reverse input cutoff clutch 360 larger, since this leads to an increase in the size of the electric actuator 400. Therefore, in the electric actuator 400 shown in FIG. 7, the reverse input cutoff clutch 360 is disposed between the motor 410 and the reducer 420. With such an arrangement of the reverse input cutoff clutch 360, when a rotational force due to an external force is reversely input, the rotational force is reduced by passing through the reducer 420. Therefore, the force related to the reverse input cutoff clutch 360 is reduced, making it possible to reduce the size of the reverse input cutoff clutch 360, and thus reducing the size of the electric actuator 400. Next, a modified example of the vehicle body tilt system 300 will be described.

[0061] Fig. 8 is a diagram showing a schematic diagram of a railway vehicle 2 incorporating a modified carbody tilting system 300. Fig. 8 shows the railway vehicle 2 in a non-tilting state (A) and a tilting state (B).

[0062] The railway vehicle 2 shown in Fig. 8 is provided with a modified carbody tilting system 300 and a carbody tilting mechanism 310 between the carbody 100 and the bogie 200. The modified carbody tilting system 300 and carbody tilting mechanism 310 shown in Fig. 8 are provided with a plurality of electric actuators 350, and each electric actuator 350 is arranged facing in a direction along the direction of gravity.

[0063] Each of the electric actuators 350 has a structure as shown in Fig. 3. When the electric actuators 350 push up the car body 100 by the same amount, the railway vehicle 2 is in a non-tilted state (A), and when the electric actuators 350 push up the car body 100 by different amounts, the railway vehicle 2 is in a tilted state (B).

[0064] Next, a specific example of carbody tilt control will be described using as an example a railway vehicle 2 incorporating a modified carbody tilt system 300. However, the specific example of carbody tilt control described below may also be adopted in the railway vehicle 1 shown in Figs. 1 and 2.

[0065] In a first specific example of vehicle body tilt control, as shown in Fig. 8, control is performed to keep the vehicle body 100 horizontal with respect to the inclination of the ground surface 500. The sensor 340 in Fig. 1 provided in the vehicle body tilt system 300 detects the inclination of the vehicle body 100, and the multiple electric actuators 350 tilt the vehicle body 100 with respect to the bogie 200 in a direction that cancels the detected inclination. As a result, the electric actuators 350 tilt the vehicle body 100 by the inclination angle of the ground surface 500 in the opposite direction to the inclination of the ground surface 500, and as a result, the vehicle body 100 is kept horizontal.

[0066] According to the first specific example of the car body tilt control, cargo and passengers inside the car body 100 are kept horizontal regardless of the inclination of the ground 500, improving the ride comfort and suppressing the collapse of cargo. The first specific example of the car body tilt control can be applied to vehicles other than railways, for example, automobiles. Fig. 9 is a diagram showing a second specific example of vehicle body tilt control, which also shows a railway vehicle 2 in a non-tilted state (A) and a tilted state (B). In a second specific example shown in FIG. 9, control is performed in response to centrifugal force that occurs when the railcar 2 travels around a curve such as a curve.

[0067] The sensor 340 of the vehicle body tilt system 300 detects the direction of the resultant force Fr of gravity Fg and centrifugal force Fc, and the electric actuators 350 tilt the vehicle body 100 in the same direction as the resultant force Fr is tilted from the direction of gravity Fg. As a result, the electric actuators 350 tilt the vehicle body 100 toward the inside of the turn by the angle between the direction of gravity Fg and the direction of the resultant force Fr, and the passengers 600 in the vehicle body 100 feel that the floor of the vehicle body 100 is directly below them, improving the ride comfort. FIG. 10 is a diagram showing a third specific example of the vehicle body tilt control.

[0068] In the first and second specific examples of carbody tilt control, carbody tilt control for a moving vehicle has been described, but in a third specific example shown in Fig. 10, carbody tilt control is performed for a stopped freight railcar 3. In the freight railcar 3, a side surface 110 of a carbody 100 is supported by a fulcrum 120 at the top so as to be freely rotatable. A load 700 such as earth and sand is loaded inside the carbody 100, and when transferring the load to a transport vehicle 800 or the like, an electric actuator 350 tilts the carbody 100 toward the transport vehicle 800. As a result, the load 700 slides along the floor of the carbody 100, pushing open the side surface 110, and the load 700 is thrown into the transport vehicle 800. In each of the specific examples described above, the electric actuator 350 can maintain the inclination of the vehicle body 100 without the supply of power, thereby achieving energy conservation.

[0069] Although the above description shows an example of application of the carbody tilting actuator and the carbody tilting system to a railway vehicle, the carbody tilting actuator and the carbody tilting system of the present invention may also be applied to other vehicles, such as automobiles.

[0070] Furthermore, although the above explanation shows an example of application of the actuator to a vehicle body tilting system, the actuator of the present invention can be applied in a wide range of fields as an actuator for devices that maintain posture, etc. against external forces, such as walking assistance devices and robot arms. [Explanation of symbols]

[0071] 1,2,3...Railway vehicle, 100...Car body, 200...Bogie, 300...Car body tilting system, 310...body tilt mechanism, 320...ECU (Electronic Control Unit), 330... vehicle body inclination control device, 340... sensor, 350... electric actuator, 10...ball screw, 20...transmission gear, 22...input side rotating shaft, 30...output shaft, 40...housing member, 51...ball bearing, 50...bearing housing, 11...screw shaft, 13... Nut, 360... Reverse input cutoff clutch, 362... Input member, 363... Output member, 364: pressed member; 365a, 365b: engaging element; 366: biasing spring; 362a...input engagement protrusion, 363a...output engagement cam, 410...motor, 420...reduction gear 500…ground, 600…passengers, 700…cargo, 800…vehicle

Claims

[Claim 1] An actuator for changing the inclination of the vehicle body; a control unit that controls the actuator to control the inclination of the vehicle body; A vehicle body tilting system comprising: The actuator, A motor; a rotating unit to which a rotational force from the motor is input; a linear motion unit that is connected to the rotating unit via a ball screw and moves linearly along the ball screw as the rotating unit rotates, thereby changing the inclination of the vehicle body; a cut-off unit that is incorporated in the rotating unit and transmits a rotational force from the motor side to the ball screw side and cuts off the rotational force from the ball screw side to stop the rotation; Equipped with A vehicle body tilt system, characterized in that the control unit stops driving the motor when the tilt of the vehicle body is to be maintained.

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