Patent Description:
Patent Literature <NUM> discloses an electric brake actuator including a service brake mechanism unit that uses rotational power of a motor to drive a push rod equipped with a friction material that is pressed against a wheel of a railroad vehicle, and a spare brake mechanism unit that uses spring force to move the push rod. In Patent Literature <NUM>, when the service brake mechanism unit cannot operate due to a power failure or the like, the spare brake mechanism unit activates the spare brake by means of the push rod that is moved by the force of a pressurized spring, so as to safely stop the railroad vehicle. Then, after recovery from the power failure, the service brake mechanism unit is operated such as to generate the maximum brake force, and the spring is pressurized again by means of the reaction force.

<CIT> relates to an electrically operated brake system for a rail vehicle, wherein each wheel of the vehicle may be braked using one or two motors, each operating a braking mechanism. The motors are powered by respective batteries.

In the technology described in Patent Literature <NUM>, when the service brake mechanism unit cannot be operated, the spare brake activated by the spring cannot be released. Accordingly, a worker who goes to the site needs to manually return the push rod in the direction of pressurizing the spring, for example, to release the spare brake.

The present invention has been made in view of such a situation, and a purpose thereof is to provide a braking device and the like that can reduce the workload related to the operation of a spare brake when a service brake cannot be used.

In response to the above issue, a braking device according to the present invention is defined by the independent claim.

According to this aspect, even when the regular electric motor and/or the regular power supply cannot be used, the spare brake can be operated with the spare electric motor and the spare power supply.

Another aspect relates to a spare brake control device. The spare brake control device includes: a spare power supply that is different from a regular power supply; a spare electric motor that drives a friction material, which is pressed against a braking target member of a railroad vehicle to brake the railroad vehicle, based on electricity supplied from the spare power supply and that is different from a regular electric motor; and an electricity supply controller that controls supply of electricity from the spare power supply to the spare electric motor in response to a spare brake command.

Optional combinations of the aforementioned constituting elements, and implementation of the present invention in the form of methods, apparatuses, systems, recording media, and computer programs may also be practiced as additional modes of the present invention.

The present invention reduces the workload related to the operation of a spare brake when a service brake cannot be used.

Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which:.

<FIG> schematically illustrates a configuration of a braking device <NUM> according to a first embodiment. The braking device <NUM> includes a brake mechanism <NUM>, a service brake unit <NUM>, and a spare brake unit <NUM> as a spare brake control device. The spare brake is sometimes referred to as a security brake, a backup brake, or an emergency brake. The service brake unit <NUM> and the spare brake unit <NUM> are controlled by commands from a brake command unit or a control unit <NUM>.

The brake mechanism <NUM>, which constitutes a tread brake, includes a shoe <NUM> as a friction material that is pressed against a wheel, which is a braking target member in a railroad vehicle, to brake the railroad vehicle. The shoe <NUM> faces at least part of the outer circumference of the wheel, and, on the facing surface (inner circumference surface), brake lining or the like is provided. As will be described later, the shoe <NUM> is driven in a radial direction of the wheel by the service brake unit <NUM> or the spare brake unit <NUM> and, when the shoe <NUM> reaches a brake action position where it comes into contact with the wheel and is then pressed, the frictional force between the brake lining or the like and the wheel slows the rotation of the wheel to brake the railroad vehicle.

The brake mechanism <NUM> may also be configured as a disc brake, and pads may be provided as the friction material instead of the shoe <NUM> used in a tread brake. The pads sandwich a brake disc, which rotates integrally with a wheel, from both sides in a rotational axis direction, and, on the surface of each pad that faces the brake disc, brake lining or the like is provided. The pads are driven in the rotational axis directions of the wheel by the service brake unit <NUM> or the spare brake unit <NUM> and, when the pads reach the brake action position where the pads come into contact with the brake disc from both sides and are then pressed, the frictional force between the brake lining or the like and the brake disc slows the rotation of the wheel to brake the railroad vehicle. The brake mechanism <NUM> may also be configured as any other arbitrary type of brake, such as a drum brake.

The brake mechanism <NUM> further includes a power transmission mechanism <NUM> connected to the service brake unit <NUM> and the spare brake unit <NUM>. When the service brake unit <NUM> is functioning, the power transmission mechanism <NUM> transmits the power of the service brake unit <NUM> to the shoe <NUM>, and, when the service brake unit <NUM> is not functioning, the power transmission mechanism <NUM> transmits the power of the spare brake unit <NUM> to the shoe <NUM>. Thus, the power transmission mechanism <NUM> preferentially transmits the power of the service brake unit <NUM> to the shoe <NUM> and transmits, only when the service brake unit <NUM> is not functioning, the power of the spare brake unit <NUM> to the shoe <NUM>. The power transmission mechanism <NUM> may be configured by a combination of publicly-known mechanical elements, such as a clutch and Torque Diode (trademark). The power transmission mechanism <NUM> may be equipped with a booster mechanism, such as a toggle mechanism, that amplifies rotational power generated by the motors of the service brake unit <NUM> and the spare brake unit <NUM>, and a reduction mechanism that obtains torque corresponding to the reduction ratio of the rotational power. The power transmission mechanism <NUM> also includes a rotational-linear transformation mechanism that transforms the rotational power generated by the motors of the service brake unit <NUM> and the spare brake unit <NUM> into linear power used to drive the shoe <NUM> in the radial direction.

The service brake unit <NUM> includes a vehicle power supply <NUM> as a regular power supply, a control circuit <NUM>, and a motor <NUM> as a regular electric motor. The vehicle power supply <NUM> may be provided outside the service brake unit <NUM> or even outside the braking device <NUM>. The vehicle power supply <NUM> may supply the control circuit <NUM> with electricity supplied from a pantograph to the railroad vehicle. The vehicle power supply <NUM> mounted on at least one railroad vehicle supplies alternating-current (AC) or direct-current (DC) electricity supplied through a train line, such as an overhead train line (overhead line) and a power feed rail (third rail), to various equipment and devices of the railroad vehicle, including the control circuit <NUM> and the motor <NUM>. The control circuit <NUM> includes an inverter for generating multiphase AC electricity of desired frequency and amplitude based on the electricity supplied from the vehicle power supply <NUM>, so as to generate AC electricity, such as three-phase AC electricity, to be applied to the motor <NUM> in response to a service brake command from the vehicle cab as the control unit <NUM>. The motor <NUM> as the regular electric motor is an AC motor, which drives the shoe <NUM> based on the AC electricity generated by the control circuit <NUM> in response to a service brake command from the control unit <NUM>.

The service brake commands from the vehicle cab as the control unit <NUM> are broadly classified into a service brake action command issued to drive the shoe <NUM> to the brake action position where the shoe <NUM> is pressed against the wheel, and a service brake release command issued to drive the shoe <NUM> to a brake release position where the shoe <NUM> is not pressed against the wheel. When the service brake action command is given by the control unit <NUM>, the control circuit <NUM> rotates the rotor of the motor <NUM> in a first direction (hereinafter, also referred to as an action direction or a normal rotation direction) to generate a first alternating current (hereinafter, also referred to as an action alternating current or a normal rotation alternating current) to drive the shoe <NUM> to the brake action position. Also, when the service brake release command is given by the control unit <NUM>, the control circuit <NUM> rotates the rotor of the motor <NUM> in a second direction (hereinafter, also referred to as a release direction or a reverse rotation direction), which is opposite to the first direction, to generate a second alternating current (hereinafter, also referred to as a release alternating current or a reverse rotation alternating current) to drive the shoe <NUM> to the brake release position.

When the service brake unit <NUM> is functioning properly, i.e., when all of the vehicle power supply <NUM>, the control circuit <NUM>, and the motor <NUM> are functioning properly, the control of action and release of the brake, i.e., driving of the shoe <NUM> between the brake action position and the brake release position, is performed by the service brake unit <NUM>. On the other hand, when the service brake unit <NUM> is not functioning properly, i.e., when at least one of the vehicle power supply <NUM>, the control circuit <NUM>, or the motor <NUM> is not functioning properly, the control of action and release of the brake, i.e., driving of the shoe <NUM> between the brake action position and the brake release position, is performed by the spare brake unit <NUM>.

The spare brake unit <NUM> constitutes a spare brake drive device that drives, when the service brake unit <NUM> is unable to drive the shoe <NUM> placed at the brake action position to the brake release position, the shoe <NUM> to the brake release position in response to a spare brake release command (shown as "RELEASE COMMAND" in <FIG>) from the control unit <NUM>. More specifically, when the service brake unit <NUM> is not functioning, the spare brake unit <NUM> drives the shoe <NUM> between the brake action position and the brake release position, based on DC electricity supplied from a battery <NUM> as a spare power supply. The spare brake unit <NUM> includes the battery <NUM>, a relay circuit <NUM> as an electricity supply controller, and a DC motor <NUM> as a spare electric motor and a DC electric motor.

The battery <NUM>, different from the vehicle power supply <NUM>, supplies DC electricity. The relay circuit <NUM> supplies the DC electricity from the battery <NUM> to the DC motor <NUM>, in response to a spare brake command as a spare brake action command and a spare brake release command from the control unit <NUM>. The DC motor <NUM> drives the shoe <NUM> between the brake action position and the brake release position, based on the DC electricity supplied from the battery <NUM> via the relay circuit <NUM>. The DC motor <NUM> may be constituted by an inverter that converts the DC electricity supplied from the relay circuit <NUM> into AC electricity, and by an electric motor, similar to the regular electric motor (motor <NUM>), that generates rotational power based on the AC electricity converted by the inverter.

<FIG> schematically illustrates the details of the relay circuit <NUM>. In the relay circuit <NUM>, a first path <NUM> and a second path <NUM>, which each connect the battery <NUM> and the DC motor <NUM>, are provided in parallel. The first path <NUM> includes a high potential line <NUM> connected to a high potential terminal <NUM> of the battery <NUM>, and a low potential line <NUM> connected to a low potential terminal <NUM> of the battery <NUM>. The high potential line <NUM> is also connected to a first terminal <NUM> of the DC motor <NUM> via a spare brake action switch <NUM>, which will be described later, and the low potential line <NUM> is also connected to a second terminal <NUM> of the DC motor <NUM> via a spare brake action switch <NUM>, which will also be described later.

The second path <NUM>, which connects the battery <NUM> and the DC motor <NUM> in parallel with the first path <NUM>, includes a first parallel line <NUM> that is connected to the high potential line <NUM> on the battery <NUM> side with respect to the spare brake action switch <NUM>, an auxiliary switch <NUM>, and a spare brake release switch <NUM>, which will be described later, and that is also connected to the second terminal <NUM> of the DC motor <NUM> with respect to the spare brake action switch <NUM>, the auxiliary switch <NUM>, and the spare brake release switch <NUM>. The second path <NUM> also includes a second parallel line <NUM> that is connected to the low potential line <NUM> on the battery <NUM> side with respect to the spare brake action switch <NUM>, an auxiliary switch <NUM>, and a spare brake release switch <NUM>, which will be described later, and that is also connected to the first terminal <NUM> of the DC motor <NUM> with respect to the spare brake action switch <NUM>, the auxiliary switch <NUM>, and the spare brake release switch <NUM>. Thus, the first parallel line <NUM> and the second parallel line <NUM> are connected to the high potential line <NUM> and the low potential line <NUM> such as to cross each other.

Each of the first path <NUM> and the second path <NUM> conducts electricity and hence supplies DC electricity to the DC motor <NUM> when all the switches provided on the path are closed. As will be described later, the first path <NUM> and the second path <NUM> do not conduct electricity simultaneously. More specifically, when the spare brake action switches <NUM> and <NUM> are closed, the first path <NUM> conducts electricity, so that the high potential terminal <NUM> of the battery <NUM> is connected to the first terminal <NUM> of the DC motor <NUM> via the high potential line <NUM>, and the low potential terminal <NUM> of the battery <NUM> is connected to the second terminal <NUM> of the DC motor <NUM> via the low potential line <NUM>. At the time, in the DC motor <NUM>, a direct current flows in the first direction from the first terminal <NUM> of high potential toward the second terminal <NUM> of low potential, and the rotor of the DC motor <NUM> rotates in the first direction (or action direction or normal rotation direction), so that the shoe <NUM> is driven to the brake action position.

Meanwhile, when the auxiliary switches <NUM> and <NUM> and the spare brake release switches <NUM> and <NUM> are closed, the second path <NUM> conducts electricity, so that the high potential terminal <NUM> of the battery <NUM> is connected to the second terminal <NUM> of the DC motor <NUM> via the first parallel line <NUM>, and the low potential terminal <NUM> of the battery <NUM> is connected to the first terminal <NUM> of the DC motor <NUM> via the second parallel line <NUM>. At the time, in the DC motor <NUM>, a direct current flows in the second direction (opposite to the first direction) from the second terminal <NUM> of high potential toward the first terminal <NUM> of low potential, and the rotor of the DC motor <NUM> rotates in the second direction (or release direction or reverse rotation direction), so that the shoe <NUM> is driven to the brake release position.

A spare relay <NUM>, which is controlled by a spare brake command as a spare brake action command from the vehicle cab as the control unit <NUM>, includes the spare brake action switch <NUM> provided on the high potential line <NUM>, the spare brake action switch <NUM> provided on the low potential line <NUM>, the auxiliary switch <NUM> provided on the first parallel line <NUM>, and the auxiliary switch <NUM> provided on the second parallel line <NUM>. These four switches <NUM>-<NUM> are mechanically connected and are biased upward in <FIG> by springs or the like. When the spare brake command is given by the vehicle cab, the switches <NUM>-<NUM> are not pressurized downward, so that, by the upward biasing force, the spare brake action switches <NUM> and <NUM> are closed, and the auxiliary switches <NUM> and <NUM> are opened. When the spare brake command is not given by the vehicle cab, on the other hand, the switches <NUM>-<NUM> are pressurized downward, so that the spare brake action switches <NUM> and <NUM> are opened, and the auxiliary switches <NUM> and <NUM> are closed. Thus, the spare brake action switches <NUM> and <NUM> and the auxiliary switches <NUM> and <NUM> are opened and closed to complement each other, based on whether or not the spare brake command is given.

Accordingly, while the first path <NUM> conducts electricity, since the spare brake action switches <NUM> and <NUM> are closed whereas the auxiliary switches <NUM> and <NUM> are open, the second path <NUM> cannot conduct electricity. Similarly, while the second path <NUM> conducts electricity, since the auxiliary switches <NUM> and <NUM> are closed whereas the spare brake action switches <NUM> and <NUM> are open, the first path <NUM> cannot conduct electricity. Therefore, the first path <NUM> and the second path <NUM> do not conduct electricity simultaneously, thereby effectively preventing the conflict between the action of the spare brake implemented by the conduction of the first path <NUM> and the release of the spare brake implemented by the conduction of the second path <NUM>.

A release relay <NUM>, which is controlled by a spare brake release command (shown as "RELEASE COMMAND" in <FIG>) from the vehicle cab as the control unit <NUM>, includes the spare brake release switch <NUM> provided in series with the auxiliary switch <NUM> on the first parallel line <NUM>, and the spare brake release switch <NUM> provided in series with the auxiliary switch <NUM> on the second parallel line <NUM>. These two switches <NUM> and <NUM> are mechanically connected and are biased upward in <FIG> by springs or the like. When the spare brake release command is given by the vehicle cab, the switches <NUM> and <NUM> are pressurized downward and closed. When the spare brake release command is not given by the vehicle cab, on the other hand, the switches <NUM> and <NUM> are not pressurized downward and hence opened by the upward biasing force.

<FIG> shows combinations of the spare brake command and the spare brake release command from the vehicle cab. In the case of "no pressurization" in which the spare brake command is given by the vehicle cab, the spare brake action switches <NUM> and <NUM> are closed, which makes the first path <NUM> conduct electricity, and the auxiliary switches <NUM> and <NUM> are opened, which does not make the second path <NUM> conduct electricity; therefore, regardless of whether or not the spare brake release command is given (pressurization or no pressurization), the DC motor <NUM> rotates normally, and the shoe <NUM> is driven to the brake action position. In short, when the spare brake command is given from the vehicle cab, the spare brake acts regardless of whether or not the spare brake release command is given.

In the case of "pressurization" in which the spare brake command is not given by the vehicle cab and, in addition, in the case of "pressurization" in which the spare brake release command is given by the vehicle cab, the auxiliary switches <NUM> and <NUM> and the spare brake release switches <NUM> and <NUM> are closed, which makes the second path <NUM> conduct electricity, and the spare brake action switches <NUM> and <NUM> are opened, which does not make the first path <NUM> conduct electricity; therefore, the DC motor <NUM> rotates reversely, and the shoe <NUM> is driven to the brake release position. In this way, when the spare brake release switches <NUM> and <NUM> are closed in response to the spare brake release command "pressurization" and also in the case of "pressurization" in which the spare brake command is not given to the spare brake action switches <NUM> and <NUM>, a direct current in the second direction (or release direction or reverse rotation direction) is applied to the DC motor <NUM> to drive the shoe <NUM> to the brake release position.

In the case of "pressurization" in which the spare brake command is not given by the vehicle cab and, in addition, in the case of "no pressurization" in which the spare brake release command is not given by the vehicle cab, the spare brake action switches <NUM> and <NUM> are opened, which does not make the first path <NUM> conduct electricity, and the spare brake release switches <NUM> and <NUM> are opened, which does not make the second path <NUM> conduct electricity; therefore, the state is placed in a "motor free" state in which the DC electricity from the battery <NUM> is not supplied to the DC motor <NUM>. This combination of the spare brake command "pressurization" and the spare brake release command "no pressurization" is set when the service brake unit <NUM> is functioning properly and there is no need to use the spare brake unit <NUM>. Thus, when the service brake unit <NUM> is functioning, the spare brake action switches <NUM> and <NUM> are not given the spare brake command and are open (pressurization), and the spare brake release switches <NUM> and <NUM> are not given the spare brake release command and are open (no pressurization).

According to the first embodiment described above, a brake, which has conventionally needed to be manually released in the event of loss of a regular power supply, for example, can be easily released, with a simple configuration including the relay circuit <NUM> constituted by switches, the DC motor <NUM>, and the like. In order to prevent abnormalities caused in the service brake unit <NUM> from affecting the spare brake unit <NUM>, it is preferable to configure the service brake unit <NUM> and the spare brake unit <NUM> with different circuit boards and to house them in different casings.

<FIG> schematically illustrates a configuration of the braking device <NUM> according to a second embodiment. Constituting elements similar to those in the first embodiment, as shown in <FIG> and the like, will be denoted by the same reference characters, and repetitive description will be omitted. The braking device <NUM> includes the brake mechanism <NUM>, the service brake unit <NUM>, and a brake release device <NUM> as a spare brake unit.

The power transmission mechanism <NUM> of the brake mechanism <NUM> is connected to the service brake unit <NUM> and the brake release device <NUM>. When the service brake unit <NUM> is functioning, the power transmission mechanism <NUM> transmits the power of the service brake unit <NUM> to the shoe <NUM>, and, when the service brake unit <NUM> is not functioning, the power transmission mechanism <NUM> transmits the power of the brake release device <NUM> to the shoe <NUM>.

When the service brake unit <NUM> is functioning properly, the control of action and release of the brake is performed by the service brake unit <NUM>. When the service brake unit <NUM> is not functioning properly, on the other hand, the control of release of the brake, i.e., the driving of the shoe <NUM> from the brake action position to the brake release position, is performed by the brake release device <NUM>.

The brake release device <NUM> constitutes a spare brake unit that drives, when the service brake unit <NUM> is unable to drive the shoe <NUM> placed at the brake action position to the brake release position, the shoe <NUM> to the brake release position in response to a brake release command (shown as "OPERATION" in <FIG>). More specifically, when the service brake unit <NUM> is not functioning, the brake release device <NUM> drives the shoe <NUM> from the brake action position to the brake release position, based on the DC electricity supplied from the battery <NUM>. The brake release device <NUM> includes the battery <NUM>, a switch <NUM> as an electricity supply controller, and the DC motor <NUM>.

The switch <NUM> supplies the DC electricity from the battery <NUM> to the DC motor <NUM>, in response to a brake release command based on operation performed by a crew member, for example, in the vehicle cab or other places. More specifically, the switch <NUM> to which the brake release command is given is closed, which supplies the DC electricity from the battery <NUM> to the DC motor <NUM>; on the other hand, the switch <NUM> to which the brake release command is not given is open, which does not supply the DC electricity from the battery <NUM> to the DC motor <NUM>. The DC motor <NUM> drives the shoe <NUM> from the brake action position to the brake release position, based on a direct current in the second direction (or release direction or reverse rotation direction) supplied from the battery <NUM> via the switch <NUM>.

According to the second embodiment described above, a brake, which has conventionally needed to be manually released in the event of loss of a regular power supply, for example, can be easily released, with a simple configuration including the switch <NUM>, the DC motor <NUM>, and the like. In order to prevent abnormalities caused in the service brake unit <NUM> from affecting the brake release device <NUM> as a spare brake unit, it is preferable to configure the service brake unit <NUM> and the brake release device <NUM> with different circuit boards and to house them in different casings.

In the second embodiment described above, a portion <NUM> enclosed by a dotted line constitutes an independent braking unit. More specifically, the braking unit <NUM> includes the power transmission mechanism <NUM> of the brake mechanism <NUM>, the control circuit <NUM> and the motor <NUM> of the service brake unit <NUM>, and the entire brake release device <NUM>. By attaching the shoe <NUM> and the vehicle power supply <NUM> to the braking unit <NUM>, the braking device <NUM> shown in <FIG> can be configured.

In a third embodiment shown in <FIG>, the braking unit <NUM> only includes the DC motor <NUM>, instead of the entire brake release device <NUM>. The battery <NUM> and the switch <NUM> as an electricity supply controller of the brake release device <NUM> are integrally provided as a power supply switch unit, which is attachable to and detachable from the braking unit <NUM> provided with the DC motor <NUM> as a spare electric motor. Thus, by making at least part of the brake release device <NUM> as a spare brake unit attachable to and detachable from the braking unit <NUM>, the remaining portion (power supply switch unit) of the brake release device <NUM> may be attached to the braking unit <NUM> only when the brake release device <NUM> needs to be used, i.e., when the service brake unit <NUM> is not functioning and the brake needs to be released by the brake release device <NUM>. By configuring the power supply switch unit separately from the braking unit <NUM>, a single power supply switch unit can be shared among multiple braking units <NUM>. As in a fourth embodiment shown in <FIG>, the entire brake release device <NUM> as a spare brake unit may be made attachable to and detachable from the braking unit <NUM>.

The present invention has been described with reference to embodiments. The embodiments are intended to be illustrative only, and it will be obvious to those skilled in the art that various modifications to a combination of constituting elements or processes could be developed and that such modifications may fall within the scope of the present invention, which is defined by the independent claim.

The functional configuration of each device described in the embodiments can be implemented by hardware resources, software resources, or cooperation between hardware resources and software resources. As the hardware resources, processors, ROMs, RAMs, or other LSIs can be employed. As the software resources, programs, such as operating system programs and application programs, can be employed.

Claim 1:
A braking device (<NUM>), comprising:
a brake mechanism (<NUM>) that presses a friction material (<NUM>) against a braking target member of a railroad vehicle to brake the railroad vehicle;
a spare electric motor (<NUM>) that drives the brake mechanism (<NUM>) and that is different from a regular electric motor (<NUM>);
a spare power supply (<NUM>) that supplies electricity to the spare electric motor (<NUM>) and that is different from a regular power supply (<NUM>); and
an electricity supply controller (<NUM>, <NUM>) that controls supply of electricity from the spare power supply (<NUM>) to the spare electric motor (<NUM>) in response to a spare brake command;
characterized in that
the regular electric motor (<NUM>) drives the friction material (<NUM>) based on alternating-current (AC) electricity, and
the braking device (<NUM>) further comprises an inverter that generates AC electricity to be applied to the regular electric motor (<NUM>) based on electricity supplied from the regular power supply (<NUM>).