U.S. patent application number 13/811746 was filed with the patent office on 2013-06-06 for brake device comprising a rotor of an eddy current disk brake, the rotor forming the brake disk of a friction disk brake.
This patent application is currently assigned to KNORR-BREMSE SYSTEME FUR SCHIENENFAHRZEUGE GMBH. The applicant listed for this patent is Miriam Van De Loecht, Manfred Walter. Invention is credited to Miriam Van De Loecht, Manfred Walter.
Application Number | 20130140112 13/811746 |
Document ID | / |
Family ID | 44534347 |
Filed Date | 2013-06-06 |
United States Patent
Application |
20130140112 |
Kind Code |
A1 |
Walter; Manfred ; et
al. |
June 6, 2013 |
BRAKE DEVICE COMPRISING A ROTOR OF AN EDDY CURRENT DISK BRAKE, THE
ROTOR FORMING THE BRAKE DISK OF A FRICTION DISK BRAKE
Abstract
A brake device of a vehicle, containing an eddy current disk
brake having a rotationally fixed stator and a rotating rotor,
wherein the rotor or the stator bears an eddy current path and the
stator or the rotor bears a magnetic arrangement, the magnetic
field lines of which induce eddy currents in the eddy current path
for generating a braking torque upon a relative movement of the
rotor with respect to the stator, and a friction disk brake having
at least one brake disk and brake pads cooperating with the brake
disk for generating a braking friction torque between the brake
disk and the brake pads, wherein the rotor of the eddy current disk
brake is formed by the brake disk of the friction disk brake.
Inventors: |
Walter; Manfred; (Neufahrn,
DE) ; Van De Loecht; Miriam; (Munich, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Walter; Manfred
Van De Loecht; Miriam |
Neufahrn
Munich |
|
DE
DE |
|
|
Assignee: |
KNORR-BREMSE SYSTEME FUR
SCHIENENFAHRZEUGE GMBH
Munich
DE
|
Family ID: |
44534347 |
Appl. No.: |
13/811746 |
Filed: |
July 27, 2011 |
PCT Filed: |
July 27, 2011 |
PCT NO: |
PCT/EP11/62902 |
371 Date: |
February 14, 2013 |
Current U.S.
Class: |
188/58 ;
188/71.1; 188/72.1 |
Current CPC
Class: |
B61H 11/14 20130101;
F16D 2127/008 20130101; F16D 2121/24 20130101; F16D 2123/00
20130101; B60T 13/586 20130101; F16D 55/2245 20130101; F16D
2125/582 20130101; H02K 49/046 20130101; F16D 2125/40 20130101;
F16D 2121/26 20130101; F16D 2121/20 20130101; F16D 2129/046
20130101; F16D 2125/52 20130101; F16D 2125/32 20130101; F16D
2129/08 20130101; B61H 5/00 20130101; F16D 2125/585 20130101; B60T
13/743 20130101; F16D 2127/06 20130101 |
Class at
Publication: |
188/58 ;
188/71.1; 188/72.1 |
International
Class: |
B61H 11/14 20060101
B61H011/14; B61H 5/00 20060101 B61H005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 28, 2010 |
DE |
10 2010 032 516.3 |
Claims
1. A brake device of a vehicle, comprising: an eddy current disk
brake having a rotationally fixed stator and a rotating rotor,
wherein the rotor or the stator carries an eddy current path and
the stator or the rotor carries a magnet arrangement, the magnetic
field lines of which induce eddy currents in the eddy current path
during relative movement of the rotor with respect to the stator in
order to generate a braking torque; and a friction disk brake
having at least one brake disk and brake pads interacting with the
brake disk in order to generate a braking friction torque between
the brake disk and the brake pads, wherein the rotor of the eddy
current disk brake is formed by the brake disk of the friction disk
brake.
2. The brake device of claim 1, wherein the magnet arrangement
contains at least one electromagnet and/or at least one permanent
magnet.
3. The brake device of claim 2, wherein the at least one
electromagnet is activated by a control unit in accordance with
operating parameters of the vehicle.
4. The brake device of claim 3, wherein the operating parameters of
the vehicle include the respective braking request and/or the speed
of the vehicle.
5. The brake device of claim 3, wherein the control unit is
integrated into a brake control unit, which also includes the
control of the friction disk brake.
6. The brake device of claim 1, wherein the stator carries the
magnet arrangement and the brake disk carries the eddy current
path.
7. The brake device of claim 1, wherein the friction disk brake
comprises a combined service and immobilization brake, wherein a
brake actuator of the service brake of the friction disk brake is
combined in a single unit with a brake actuator of the
immobilization brake of the friction disk brake.
8. The brake device of claim 7, wherein the brake actuator of the
service brake of the friction disk brake can be actuated
electrically and/or pneumatically and wherein the brake actuator of
the immobilization brake of the friction disk brake contains a
spring accumulator that outputs the application force.
9. The brake device of claim 8, wherein the brake actuator of the
service brake of the friction disk brake and the brake actuator of
the immobilization brake of the friction disk brake act on a common
brake caliper having caliper levers which carries the brake pads of
the friction disk brake at the ends.
10. A rail vehicle containing a brake device as claimed in claim 1.
Description
PRIORITY CLAIM
[0001] This patent application is a U.S. National Phase of
International Patent Application No. PCT/EP2011/062902, filed 27
Jul. 2011, which claims priority to German Patent Application No.
10 2010 032 516.3, filed 28 Jul. 2010, the disclosures of which are
incorporated herein by reference in their entirety.
FIELD
[0002] Disclosed embodiments relate to a brake device of a vehicle,
containing an eddy current disk brake having a rotationally fixed
stator and a rotating rotor, wherein the rotor or the stator
carries an eddy current path and the stator or the rotor carries a
magnet arrangement, the magnetic field lines of which induce eddy
currents in the eddy current path during relative movement of the
rotor with respect to the stator in order to generate a braking
torque, and a friction disk brake having a brake disk and brake
pads interacting with the brake disk in order to generate a braking
friction torque between the brake disk and the brake pads.
BACKGROUND
[0003] Three wheel brake systems are currently used in friction
disk brakes in the rail vehicle sector: pneumatic or
electropneumatic brake systems, hydraulic or electrohydraulic brake
systems and mechanical or electromechanical brake systems. In this
context, the friction disk brake system can be embodied as an
active or passive brake system, depending on whether the force of
the brake actuator has to be applied in order to brake (active
brake system) or in order to release the brake (passive brake
system). For the eventuality of malfunctions in operation, energy
is stored in compressed air reservoirs in pneumatic systems, in
hydraulic reservoirs in hydraulic systems and in the form of
accumulator springs in electromechanical systems.
[0004] Electromechanical friction disk brakes for rail vehicles
which have a service brake unit and an accumulator-type brake unit
having an energy storage device are known from the prior art, e.g.
from WO 02/49901 A1. The service brake unit contains a braking
force generator or brake actuator for applying and/or releasing the
brake, e.g. in the form of an electric motor drive. The
accumulator-type brake unit comprises at least one energy storage
device for storing and releasing energy for applying the brake as
an in-service emergency brake in the sense of a backup safety level
for the failure of the service brake unit and/or as a parking or
immobilization brake. The accumulator-type brake unit is generally
designed as a spring brake. A force converter provides conversion
of the energy output by the braking force generator and/or by the
energy storage device into a brake application movement and, for
example, comprises a brake spindle driven by the electric motor
drive. When the spring brake is triggered in the case of parking or
emergency braking, the potential energy stored in the accumulator
spring is released and converted into a high kinetic energy of the
elements of the force converter.
[0005] In this friction disk brake, which is generally used to
supplement electrodynamic and hydrodynamic brakes on driving axles
and carrying axles of rail vehicles, the braking effect is the
result of friction between the brake pads and the brake disk. The
disadvantage with such friction disk brakes is the brake pad wear
and the brake abrasion which occurs during this process. Moreover,
cracks can form due to local stresses. These local stresses,
referred to as hot spots, are caused by uneven brake pad and brake
disk surfaces, causing the brake pads to act on the brake disk at
individual points and leading to the thermal or braking energy
being introduced unevenly into the brake disk.
[0006] A brake device in which a friction brake and an eddy current
disk brake are constructed separately as an electrodynamic brake
and arranged in a rail vehicle is known from DE-A-2 213 050, which
defines the relevant type, it being possible to use both kinds of
brake jointly to brake the rail vehicle. This is referred to as
"brake blending".
[0007] In most cases, that part of the eddy current disk brake
which generates the magnetic force lines is mounted on fixed parts
of the vehicle, e.g. in the case of rail vehicles, on the bogie,
and the eddy current disk brake is mounted on those parts which are
to be braked, e.g. on an axle.
[0008] Here, braking is performed as far as possible with the eddy
current disk brake as the service brake since it is almost
wear-free, being dependent on force-based engagement. Eddy current
disk brakes of this kind are generally integrated into the drives,
and therefore act only on driving axles. The disadvantage here is
that their braking performance is speed-dependent; in particular,
the braking torque decreases as the speed of rotation of the rotor
falls, for which reason they cannot be used for braking to a halt
and cannot hold a parked rail vehicle in its immobilized position.
Moreover, the high additional weight and additional installation
space required by electrodynamic eddy current disk brakes used in
addition to friction brakes are disadvantageous, especially in
spatially restricted bogies of rail vehicles.
SUMMARY
[0009] Disclosed embodiments provide a brake device of the type
mentioned at the outset in such a way that it takes up less
installation space and has a lower weight.
BRIEF DESCRIPTION OF THE FIGURES
[0010] In the drawings:
[0011] FIG. 1 shows a sectioned representation of at least one
disclosed embodiment of a brake caliper unit of a friction disk
brake in the release position;
[0012] FIG. 2 shows an enlarged view of FIG. 1; and
[0013] FIG. 3 shows a highly schematized representation of a brake
device according to at least one disclosed embodiment having an
eddy current disk brake and a friction disk brake as shown in FIG.
1.
DETAILED DESCRIPTION
[0014] Disclosed embodiments are based on the concept that the
rotor of the eddy current disk brake as a rotary eddy current brake
is formed by the brake disk of the friction disk brake. The eddy
current brake disk and the friction brake disk are therefore formed
by a single component.
[0015] Thus, a brake disk of this kind manages to combine two
functions in one component, serving, on the one hand, as a friction
partner for the brake pads of the friction disk brake and, on the
other hand, also at the same time as the rotor of the eddy current
disk brake. The only additional component required to obtain an
eddy current disk brake is a stator interacting with the brake
disk, the latter already being present as part of the friction disk
brake, which stator optionally carries the unit generating the
magnetic force lines, e.g. an electromagnet.
[0016] As a result, the number of components used in both types of
brake is advantageously reduced, and consequently the weight of the
brake device is also reduced, this being advantageous with regard
to the restricted installation space in the region of rail vehicle
bogies and the unsprung masses. Last but not least, the compact
construction of the brake device makes it easier to install in the
bogie.
[0017] In other words, disclosed embodiments combine a friction
disk brake having an integrated spring brake and an eddy current
disk brake suitable for open-loop and/or closed-loop control in
order to generate a required service braking torque in succession
and/or simultaneously and in order to generate an immobilization
braking torque by means of the spring brake to prevent the parked
vehicle from rolling away.
[0018] The friction disk brake may transmit the braking force to a
friction surface of the brake disk by means of a brake caliper,
brake pad holders and brake pads. The immobilization brake can be
implemented by means of the spring brake integrated into the
friction disk brake, the spring brake producing a continuous
mechanical spring force on the brake caliper when the air is
released, for example.
[0019] The brake device can be used for driving axles or carrying
axles, thus making it possible in a simple manner to also brake
carrying axles without wear and thereby reduce pad wear at the
carrying axles.
[0020] In at least one disclosed embodiment, the magnet arrangement
contains at least one electromagnet and/or at least one permanent
magnet. In the case of electromagnets, a magnetic field is
generated in a known manner when they are excited, the magnetic
field lines of the magnetic field inducing eddy currents in the
eddy current path optionally formed on or in the brake disk during
relative movement of the brake disk as the rotor with respect to
the electromagnet as the stator, the eddy currents exerting a
braking torque on the brake disk.
[0021] The at least one electromagnet is activated by a control
unit, for example, in accordance with operating parameters of the
vehicle, wherein the operating parameters of the vehicle include
the respective braking request and/or the speed of the vehicle. To
save additional installation space, this control unit is integrated
into a brake control unit, which also includes the control of the
friction disk brake.
[0022] The friction disk brake may be a combined service and
immobilization brake, wherein a brake actuator of the service brake
is combined in a single unit, optionally in a brake caliper unit,
with a brake actuator of the immobilization brake. In this case,
the brake actuator of the service brake of the friction disk brake
can be actuated electrically and/or pneumatically, for example, and
the brake actuator of the immobilization brake of the friction disk
brake contains a spring accumulator that outputs the application
force. As part of the brake caliper unit, the brake actuator of the
service brake of the friction disk brake and the brake actuator of
the immobilization brake of the friction disk brake act on a common
brake caliper which carries the brake pads of the friction disk
brake at the ends.
[0023] Further embodiments are disclosed below together with
reference to the drawings.
[0024] With this understanding in mind, within the drawings, the
brake actuator 1 denoted by 1 in FIG. 1 and shown in a release
position is used as a drive unit for a friction disk brake 2, e.g.
an electromechanical friction disk brake, of a rail vehicle. The
brake actuator 1 has a substantially hollow-cylindrical actuator
housing 3, which is closed off toward one axial end by a cover
section 4, which has an end opening 6. Starting from the cover
section 4, the actuator housing 3 is of substantially double-walled
design, wherein an inner accumulator spring 10 and an outer
accumulator spring 12 coaxial with the latter are arranged in the
space between an inner wall 7 and an outer wall 8, with the outer
accumulator spring 12 surrounding the inner accumulator spring
10.
[0025] The accumulator springs 10, 12 may be designed as helical
springs and are each supported at one end on the actuator housing
3. The other end of the outer accumulator spring 12 is supported on
an annular collar 14 of an outer sliding sleeve 16, and the other
end of the inner accumulator spring 10 is supported on an annular
collar 18 of an inner sliding sleeve 20, wherein the inner sliding
sleeve 20 is interposed between the outer sliding sleeve 16 and the
inner wall 7 of the actuator housing 3. The inner and the outer
sliding sleeve 16, 20 are furthermore guided movably on one another
in the axial direction, and the inner sliding sleeve 20 is guided
movably on a radially inner circumferential surface of the inner
wall 7 of the actuator housing 3, wherein the outer sliding sleeve
16 comes to rest against an axial stop 22 of the inner sliding
sleeve 20 in the release position. The annular collar 14 of the
outer sliding sleeve 16 furthermore projects beyond the annular
collar 18 of the inner sliding sleeve 20 in the axial and the
radial direction.
[0026] An SR motor 24 (switched reluctance motor) that can be
operated in four-quadrant mode is accommodated in the cover section
4, on the side facing away from the accumulator springs 10, 12. The
SR motor 24 contains a radially outer stator 30, which is fixed
with respect to the housing and which surrounds a rotor 32, which
can be braked by means of a holding brake 34, optionally a
permanent magnet brake, which is closed when deenergized and open
when energized.
[0027] As can be seen best from FIG. 2, the rotor 32 is seated on a
hollow shaft 36, which is rotatably mounted in the actuator housing
3 by means of ball bearings 38 and is provided on its radially
inner circumferential surface with an axially extending set of
splines 40, in which radially outer fins 42 of an intermediate
sleeve 44 extending in the axial direction engage. As a result, the
intermediate sleeve 44 is guided in such a way as to be
non-rotatable relative to the hollow shaft 36 but capable of axial
movement.
[0028] An end journal 46 of a brake spindle 48 projects coaxially
into an end of the intermediate sleeve 44 which faces the
accumulator springs 10, 12 and is held there in an axially fixed
manner and in a manner fixed against relative rotation. The other
end of the brake spindle 48 projects into a cup-shaped section 50
of a connecting rod 52 for an eccentric lever 53, as FIG. 1 shows.
The cup-shaped section 50 of the connecting rod 52 is held in an
axially fixed manner in the outer sliding sleeve 16 but is allowed
to pivot sideways by a universal ball joint. A lug is formed on
that end of the connecting rod 52 which faces away from the
accumulator springs 10, 12, into which lug there engages a pin 55,
which is connected to one end of the eccentric lever 53 of an
eccentric arrangement. The eccentric arrangement has an eccentric
shaft 56, which is attached in an articulated manner to a caliper
lever 57 and, together with a further caliper lever 57', forms a
brake caliper. Respective pad holders with brake pads 58, which can
be moved in the direction of the axis of a brake disk 59, are
arranged at one end of each of the caliper levers 57, 57'. The ends
of the caliper levers 57, 57' which face away from the brake pads
58 are connected to one another by a pushrod actuator 59', which
may be of an electrically actuated design.
[0029] As is evident from FIG. 2, the brake spindle 48 is rotatably
mounted within the inner sliding sleeve 20, optionally by means of
a double-row deep-groove ball bearing 61, which can absorb both
axial and radial forces and of which an inner ring is preloaded
against a shoulder 62 of the brake spindle 48 by a nut 60 screwed
onto an outer threaded section of the brake spindle 48 and is
thereby held on the brake spindle 48 in a manner fixed against
relative rotation and in an axially fixed manner. An outer ring of
the deep-groove ball bearing 61 is likewise held in a manner fixed
against relative rotation and in an axially fixed manner in the
inner sliding sleeve 20.
[0030] The brake spindle 48 is surrounded by a nut/spindle unit 64,
which may be designed as a rolling-contact thread drive, e.g. a
recirculating ball screw, roller screw, satellite roller screw or
planetary rolling-contact screw. The cup-shaped section 50 of the
connecting rod 52 is inserted into the outer sliding sleeve 16 to
such an extent here that the nut 66 of the nut/spindle unit 64 is
clamped between a radially inner shoulder 68 of the outer sliding
sleeve 16 and an end face of the cup-shaped section 50 of the
connecting rod 52, thus ensuring that it is held securely against
rotation relative to the latter. During rotations of the brake
spindle 48, the nut 66 is therefore guided in translation along the
brake spindle 48 and takes the outer sliding sleeve 16 and the
connecting rod 52 with it in the process.
[0031] An annular space 70 is formed in the cover section 4 of the
actuator housing 2, in which space a ring gear 76 in driving
connection with a locking nut 72 via a slipping clutch 74 is
accommodated coaxially with respect to the brake spindle 48. The
ring gear 76 is seated on the radially outer circumferential
surface of the locking nut 72 and is connected to the latter for
conjoint rotation by the slipping clutch 74 up to an upper limiting
torque. The slipping clutch 74 may be formed by axially
intermeshing face gear teeth 78 on the ring gear 76 and on the
locking nut 72, wherein a diaphragm spring pack 82, which is
supported axially on the actuator housing 3 by a snap ring 80 and
acts on a radial deep-groove ball bearing 84 which supports the
locking nut 72 relative to the actuator housing 3, provides the
axial force required for force- and form-locking engagement of the
face gear teeth 78. On its side facing away from the face gear
teeth 78, the ring gear 76 is supported axially with respect to the
actuator housing 3 by an axial needle bearing 86. The locking nut
72 surrounds the inner sliding sleeve 20 and is rotatably mounted
on the latter by means of a non-self-locking thread 88.
[0032] An electromagnetically actuable locking device 90 may have a
housing 92, which is flanged to a radial opening of the annular
space 70. The locking device 90 comprises a shaft 94, at the
radially inner end of which a bevel wheel 96 is arranged and at the
opposite, radially outer end, of which a cylindrical flywheel 98 is
arranged. The bevel wheel 96 meshes with the teeth of the ring gear
76 and, with the latter, forms a bevel wheel mechanism, which may
have a relatively high transmission ratio, which is in a range of
3.0 to 8.0, for example. The shaft 94 is rotatably mounted in the
housing 92 of the locking device 90 by deep-groove ball bearings
100, with the shaft 94 being arranged perpendicularly to the brake
spindle 48.
[0033] On its face facing the brake spindle 48, the flywheel 98 has
an annular recess 102 for a ring 104, which is arranged coaxially
with the shaft 94 and is accommodated in a manner which allows
movement along pins 106 extending in the axial direction, and it is
therefore connected for conjoint rotation to the flywheel 98. On
its face facing away from the flywheel 98, the ring 104 furthermore
has a radially outer toothed rim 108, which lies opposite a further
toothed rim 108' supported on the housing 92 of the locking device
90 and is pushed away from the further toothed rim by the action of
compression springs 110. Opposite the ring 104 there are
furthermore two solenoids 112, 112' arranged axially one behind the
other in the housing 92 of the locking device 90, and the solenoids
can be energized by means of an electric terminal 114. The ring
104, the two toothed rims 108, 108' and the two solenoids 112, 112'
together form a solenoid-operated toothed brake 116.
[0034] In the case of energized solenoids 112, 122', magnetic
forces of attraction arise which move the ring 104 in the axial
direction along the pins 106 toward the solenoids 112, 112',
against the action of the compression springs 110, as a result of
which the toothed rim 108 of the ring 104 comes into engagement
with the toothed rim 108' held on the housing 92 of the locking
device 90 and thus enters into a connection therewith so as to be
fixed against relative rotation. A torque introduced into the
locking device 90 via the ring gear 76 can then be supported on the
housing 92 of the locking device 90, with the flow of force passing
through the bevel wheel 96, the shaft 94 and the flywheel 98.
[0035] In the release position of the solenoid-operated toothed
brake 116, on the other hand, the solenoids 112, 112' are
deenergized, and therefore the toothed rim 108 of the ring 104
moves out of engagement with the toothed rim 108' held on the
housing 92 of the locking device 90 owing to the action of the
compression springs 110 and, as a result, the ring gear 76,
together with the bevel wheel 96, the shaft 94 and the flywheel 98,
can rotate freely relative to the housing 92 of the locking device
90. Together, the flywheel 98, the ring 104, the shaft 94 and the
bevel wheel 96 then form an inertia mass 118, which can be rotated
perpendicularly to the brake spindle 48 or to the brake application
direction and is arranged on the far side of the locking nut 72
from the slipping clutch 74, wherein the share of the flywheel 98
in the mass moment of inertia of the inertia mass 118 is the
greatest, owing to its radius.
[0036] The SR motor 24 forms a braking force generator, while the
other elements of the force transmission path from the SR motor 24
to the caliper levers 57, 57' form a braking force converter 120.
An electric motor 24 may be used as a braking force generator. As
an alternative, however, the braking force generator could also be
a hydraulic or pneumatic brake cylinder acting in one or two
directions of actuation or some other unit acting in one or two
directions. The locking device 90, the permanent magnet brake 34
and the SR motor 24 can be activated by an electronic control and
regulating device (not shown). Given this background, the brake
actuator 1 or friction disk brake 2 operates as follows:
[0037] In the release position of the brake actuator 1, which is
shown in FIG. 1, the outer and inner accumulator springs 10, 12 are
preloaded. The force of the inner accumulator spring 10 is
transmitted by the inner sliding sleeve 20, via the
non-self-locking thread 88, to the locking nut 72 and, from there,
via the slipping clutch 74, to the ring gear 76 and the flywheel
98. Owing to the spring force of the inner accumulator spring 10, a
torque is produced in the non-self-locking thread 88, i.e. the
locking nut 72 wants to turn together with the inertia mass 118,
but this is prevented by the energized and therefore closed
solenoid-operated toothed brake 116.
[0038] The force of the outer accumulator spring 12 is supported by
the outer sliding sleeve 16 on the nut 66 of the nut/spindle unit
64, although the nut/spindle unit 64 is not self-locking. This is
because the torque which arises in the brake spindle 48 owing to
the force of the outer accumulator spring 12 is introduced into the
actuator housing 3 via the permanent magnet brake 34, which is
closed in the release position. From the nut 66, the flow of force
runs via the brake spindle 48 and the double-row deep-groove ball
bearing 61 into the inner sliding sleeve 20 and, from there, into
the ring gear 76 over the same path as the force of the inner
accumulator spring 10. This means that both the outer and the inner
accumulator spring 10, 12 are held in the loaded state by the
locking device 90 in the release position.
[0039] At the transition from the release position to a service
braking operation, the permanent magnet brake 34 is energized by
the electronic control and regulating device, as a result of which
the brake 34 opens and allows rotation of the SR motor 24, which is
likewise supplied with electric energy by the control and
regulating device. Rotation of the rotor 32 and of the brake
spindle 48 extends the nut 66 of the nut/spindle unit 64, together
with the outer sliding sleeve 16 and the connecting rod 52, into
the service braking position. This extension movement of the
connecting rod 52 is assisted by the outer accumulator spring 12,
which, in terms of function, is connected in parallel with the SR
motor 24.
[0040] The activation of the SR motor 24 by the control and
regulating device and the outer accumulator spring 12 are
coordinated with one another in such a way that the outer
accumulator spring 12 alone produces a defined braking force value
lying between a minimum and a maximum braking force and defining an
operational zero point. At the operational zero point, the SR motor
24 is deenergized. The magnitude of the braking force acting at the
operational zero point is therefore dependent, inter alia, on the
spring rate of the outer accumulator spring 12 and the degree of
preloading. To achieve the maximum braking force, the SR motor 24
is controlled in such a way in four-quadrant mode by the control
and regulating device that it assists the outer accumulator spring
12 by turning in the brake application direction and outputting a
positive braking torque, corresponding, for example, to operation
in the first quadrant. To achieve a braking force less than that at
the operational zero point, the SR motor 24 does rotate in the
brake application direction but, like a generator, delivers a
negative torque, which acts against the outer accumulator spring 12
via the nut/spindle unit 64 (operation in the second quadrant). The
inner accumulator spring 10 does not participate in the generation
of the service braking force and remains in the loaded state since
the locking nut 72 is locked by the solenoid-operated toothed brake
116, which continues to be energized.
[0041] The controlled application of the immobilization or parking
brake is initiated by the service braking operation described above
until a braking force approximately 20% lower than the ultimate
force to be achieved with the immobilization brake is reached. By
means of appropriate control signals from the control device, the
SR motor 24 is shut down, the permanent magnet brake 34 is closed
by interrupting the power supply, and the solenoid-operated toothed
brake 116 is released by switching off the current. Owing to the
spring force acting on the inner sliding sleeve 20 and produced by
the inner accumulator spring 10, a torque is produced in the
non-self-locking trapezoidal thread 88 between the locking nut 72
and the inner sliding sleeve 20, which torque is no longer
supported by the now freely rotatable inertia mass 118.
Consequently, the locking nut 72 begins to rotate on the inner
sliding sleeve 20, which then moves in the brake application
direction and takes the outer sliding sleeve 16 with the connecting
rod 52 along by way of its axial stop 22. At the same time, the
unlocked outer sliding sleeve 16 can move in the brake application
direction owing to the spring force of the outer accumulator spring
12. It is immaterial here whether the permanent magnet brake 34 is
open or closed during this process since the intermediate sleeve 44
together with the brake spindle 48 moves axially during this
process in the set of splines 40 of the hollow shaft 36 of the
rotor 32. In the immobilization braking position, a total braking
force resulting from the sum of the spring forces of the two
parallel-acting accumulator springs 10, 12 is therefore in
effect.
[0042] During the brake application movement, the rotation of the
locking nut 72 is converted by the bevel wheel mechanism 76, 96
into a higher-speed rotation of the inertia mass 118, with the
result that a large part of the potential energy of the expanding
accumulator springs 10, 12 is converted into rotational energy.
Once the braking position is reached, the entire energy supply can
be switched off, and the rail vehicle is held reliably in the
immobilization braking position by the spring forces of the inner
and outer accumulator springs 10, 12. In order to maintain the
immobilization braking force achieved thereby over a prolonged
period, only slight relaxation can be permitted in the inner and
outer accumulator springs 10, 12. Optionally, both accumulator
springs 10, 12 consist of high-strength silicon spring wire CrSiVa
TH-381 HRA from Trefileurope.
[0043] Once the braking position is reached, the rotation of the
locking nut 72 stops. The slipping clutch 74 between the locking
nut 72 and the ring gear 76 is designed in such a way that the
upper limiting torque, above which relative rotation between the
face gear teeth 78 can take place, is exceeded in the braking end
position by the torque which is the product of the mass moment of
inertia of the inertia mass 118 and the retardation present after
traversal of the brake application stroke, with the result that,
after reaching the braking position, the inertia mass 118 can
initially continue to rotate and is slowly brought to a halt
essentially by the friction which occurs between the face gear
teeth 78 of the ring gear 76 and the locking nut 72. A gradual
reduction in the rotational energy stored in the inertia mass 118
can thereby be achieved.
[0044] If the power supply to the brake actuator 1 and/or the
control and regulating device and a higher-ranking vehicle control
system fail during a service braking operation, the solenoids 112,
112' of the locking device 90 are no longer energized, with the
result that the compression springs 110 pull the ring 104 back in
the direction of the flywheel 98 and hence release the
solenoid-operated toothed brake 116. The subsequent events are
identical with those described previously in connection with an
immobilization or parking brake operation, and therefore the total
braking force is obtained from summation of the spring forces of
the two parallel-acting accumulator springs 10, 12 in the case of
an emergency or safety braking operation as well.
[0045] Release of the brake, starting from the immobilization
braking or emergency braking position, takes place in two steps,
wherein first of all the inner accumulator spring 10 is subjected
to load. The permanent magnet brake 34 is energized by the control
and regulating device and hence open, and the SR motor 24 is driven
in the brake application direction. During this process, the
rotating brake spindle 48 is supported on the nut 66 of the
nut/spindle unit 64 and moves together with the inner sliding
sleeve 20 in the direction of the release position. During this
process, the locking nut 72 rotates on the inner sliding sleeve 20
while the locking device 90 is open. When the loaded state of the
inner accumulator spring 10 is reached, which corresponds to the
state in the release position, the SR motor 24 is stopped by the
control and regulating device, and the locking device 90 is brought
into the locking position by energizing the solenoids 112, 112'.
However, the inner accumulator spring 10 can be subjected to load
even when the solenoids 112, 112' are already energized and the
locking device 90 is therefore closed.
[0046] In a further step, the outer accumulator spring 12 is
subjected to load by operating the SR motor 24 in the opposite
direction of rotation, i.e. in the release direction, wherein the
rotation of the brake spindle 48, which is supported on the locked
inner sliding sleeve 20, screws the nut 66 of the nut/spindle unit
64, together with the outer sliding sleeve 16, in the direction of
the release position. The SR motor 24 is then switched off, and the
permanent magnet brake 34 is activated.
[0047] As FIG. 3 shows, the friction disk brake in FIG. 1 and FIG.
2 is combined with an eddy current brake 122, which comprises a
rotationally fixed stator 124 and a rotating rotor 59, wherein, for
example, the rotor 59 carries an eddy current path 126 and the
stator 124 carries a magnet arrangement 128, the magnetic field
lines of which induce eddy currents in the eddy current path 126
during relative movement of the rotor 59 with respect to the stator
124 in order to generate a braking torque.
[0048] In this case, the rotor of the eddy current brake 122 is
formed by the brake disk 59 of the friction disk brake 2. The
magnet arrangement 128 may contain an electromagnet, which, when
excited, generates a magnetic field in a known manner, the magnetic
field lines of which induce eddy currents in the eddy current path
126 formed at or in the brake disk 59 during relative movement of
the brake disk 59 as the rotor with respect to the electromagnet
128 as the stator. The electromagnet 128, which is supplied with
power by the onboard electrical system of the rail vehicle, is
activated via a control unit 130 in accordance with operating
parameters of the rail vehicle, wherein the operating parameters of
the rail vehicle include the respective braking request and/or the
speed of the rail vehicle. This control unit 130 is integrated into
a brake control unit (not shown explicitly here), which also
comprises the control system for the friction disk brake 2.
[0049] If a power supply for the electromagnet 128 is activated
through control by control unit 130, eddy currents running counter
to the direction of rotation of the brake disk 59 in a known manner
are induced in the eddy current path 126 of the brake disk 59, and
a braking torque on the brake disk 59 is thereby produced. The eddy
current path 126 is then the ferromagnetic part of the brake disk
59, which is encompassed by the field lines of the magnetic field.
In the present case, the brake disk 59 may be composed completely
of ferromagnetic material, and therefore the eddy current path 126
is formed approximately by the entire brake disk 59.
[0050] The friction disk brake 2 and the eddy current disk brake
122 as an electrodynamic brake are then arranged jointly as a unit
in a bogie of the rail vehicle, wherein the common brake disk 59 is
arranged on a rotating driving axle 132 of the bogie. For service
braking, both brakes 2, 122 can then be used individually and/or in
combination in any desired manner, e.g. simultaneously or in
succession. As an alternative, the brake disk 59 could, of course,
also be arranged on an undriven axle. The immobilization brake is
then formed exclusively by the friction disk brake 2 or integrated
into the latter, as described above.
[0051] The brake device, which comprises the friction disk brake 2
and the eddy current disk brake 122, is not restricted to
application on rail vehicles. On the contrary, it can be used as a
combined electrodynamic brake/friction disk brake in any type of
vehicle, e.g. for road vehicles or utility vehicles.
LIST OF REFERENCE SIGNS
[0052] 1 brake actuator [0053] 2 friction disk brake [0054] 3
actuator housing [0055] 4 cover section [0056] 6 bore [0057] 7
inner wall [0058] 8 outer wall [0059] 10 inner accumulator spring
[0060] 12 outer accumulator spring [0061] 14 annular collar [0062]
16 outer sliding sleeve [0063] 18 annular collar [0064] 20 inner
sliding sleeve [0065] 22 axial stop [0066] 24 SR motor [0067] 30
stator [0068] 32 rotor [0069] 34 holding brake [0070] 36 hollow
shaft [0071] 38 ball bearing [0072] 40 sets of splines [0073] 42
fins [0074] 44 intermediate sleeve [0075] 46 journal [0076] 48
brake spindle [0077] 50 cup-shaped section [0078] 52 connecting rod
[0079] 53 eccentric lever [0080] 55 pin [0081] 56 eccentric shaft
[0082] 57 caliper lever [0083] 57' caliper lever [0084] 58 brake
pads [0085] 59 brake disk [0086] 59' pushrod actuator [0087] 60 nut
[0088] 61 deep-groove ball bearing [0089] 62 shoulder [0090] 64
nut/spindle unit [0091] 66 nut [0092] 68 shoulder [0093] 70 annular
space [0094] 72 locking nut [0095] 74 slipping clutch [0096] 76
ring gear [0097] 78 face gear teeth [0098] 80 snap ring [0099] 82
diaphragm spring pack [0100] 84 deep-groove ball bearing [0101] 86
axial needle bearing [0102] 88 thread [0103] 90 locking device
[0104] 92 housing [0105] 94 shaft [0106] 96 bevel wheel [0107] 98
flywheel [0108] 100 deep-groove ball bearing [0109] 102 annular
recess [0110] 104 ring [0111] 106 pin [0112] 108 toothed rim [0113]
108' toothed rim [0114] 110 compression springs [0115] 112 solenoid
[0116] 112' solenoid [0117] 114 electric terminal [0118] 116
solenoid-operated toothed brake [0119] 118 rotational inertia mass
[0120] 120 braking force converter [0121] 122 eddy current disk
brake [0122] 124 stator [0123] 126 eddy current path [0124] 128
magnet arrangement [0125] 130 control unit
* * * * *