Title of the Invention
Disc PadBrake Pad
Background of the Invention
1. Field of the Invention
The present invention relates to a disc padbrake pad of for
use in a vehicle.
2. Background Art
Generally, in a disc padbrake pad for use inof a vehicle,
for example, as disclosed in Japanese Patent Laid-Open Publication
No. 7-158673 and Japanese Patent Laid-Open Publication No.
2004-522118, a friction member is fixedly attached to a
reinforcing plate, or the like, which is mounted to a back plate.
More specifically, in a brake pad disclosed in Japanese Patent
Laid-Open Publication No. 7-158673, in a state where athe friction
member is fitted to athe reinforcing plate, the friction member
is sintered, and the reinforcing plate is fastened to athe back
plate with a rivet. Meanwhile, in a brake pad disclosed in
Japanese Patent Laid-Open Publication No. 2004-522118, a rough
base support covered with a rough base is weldedsintered to athe
back plate, and athe friction member is pressed onto the rough
base support.
The brake pads disclosed in the above Publications includes
thea reinforcing plate or thea rough base support to, thereby

preventing the friction member from breakingfalling off from the
reinforcing plate or the rough base support. However, in the case
of using where a sintered material having in which various
substances are dispersed in a base materialmain material asis used
for the a friction member, because coefficients of thermal
expansion coefficients of the dispersed substances are different
from that of the base materialmain material. Thus, the substances
are likelymay be to separated from the base materialmain material
at their respective boundary surfaces therebetween due to
frictional heat , and the like to consequently cause, and a crack
may be generated along the boundary surface in an intermediate
portion, in a thickness direction, of the friction member. If
such crack appearsn this case, in these brake pads, the friction
member is firmly coupled to the reinforcing plate or the rough
base support, but it is difficult to prevent a part of the friction
member on a friction surface side from breakingfalling off
although the friction member is firmly coupled to the reinforcing
plate or the rough base support. SpecificallyIn other words, if
when a crack appearsis generated in the friction member along the
back plate direction because the friction member receives by a
shear force received by the friction member at braking, the crack
gradually develops due to continued use of the brake pad, and hence
causing there is a fear that a part of the friction member will
be partially separate and d so as to then breakfall off due to
the crack.

Summary of the Invention
An object of the present invention is to provide a disc
padbrake pad which can effectiveffectiveely prevents a friction
member from even partially breakingfalling off.
A disc padbrake pad according to an aspect of the present
invention is a disc padbrake pad to be pressed against a brake
disc and comprisesing: a basebase member; a friction block which
includinges a support member, and a friction member fixedly
attached to a surface of the support member, the friction block
beingand which is mounted to the basebase member; an elastic member
which is provided between the basebase member and the friction
block for allowingand which presses the friction blockblock to
tilt and move in a direction of approaching the base member when
the friction block is pressed against toward the brake disc so
as to allow the friction block to move in a direction to approach
the base and so as to allow the friction member to be displaced
at a tilt; and a plurality of projection portions which each project
from the surface of the support member to which the friction member
is fixedly attached, and each extend to each of which has such
a height as to reach a friction surface of the friction member
or a vicinity of the friction surface of the friction member, and
each haveeach of which has irregularities in a rugged side surface
thereof, and which are fixed to the plurality of projections and
the friction member being firmly integrated with each other.

Brief Description of the Drawings
FIG. 1 is a cross-sectional view of a disc padbrake pad
according to an embodiment of the present invention.
FIG. 2A is a cross-sectional view showing a friction block
used in the disc padbrake pad.
FIG. 2B is a plan view showing the friction block used in
the disc padbrake pad.
FIG. 3 is a cross-sectional view of a disc padbrake pad
according to another alternative embodiment.
FIG. 4A is a cross-sectional view showing a friction block
used in the disc padbrake pad shown in FIG. 3.
FIG. 4B is a plan view showing the friction block used in
the disc padbrake pad shown in FIG. 3.
Detailed Description of the Preferred Embodiments of the Invention
The following will describe a best mode for carrying out
the present invention in detail with reference to the drawings.
FIG. 1 shows an embodiment of a disc padbrake pad according
to an embodiment of the present invention. The disc padbrake pad
10 according toof the present embodiment is used f orin a disc brake
provided inof a high-speed rail vehicle. A plurality of the disc
padbrake pads 10 areis arranged with respect toalong a
circumferential direction of a rotational surface of a brake disc
(not shown) . The disc padbrake pad 10 includes a base 12base

member 12 and a plurality of friction blocks 14 mounted to the
base 12base member 12.
The base 12base member 12 has is formed in the shape of an
elongated flat plate extending in one direction in a plan view.
The base 12base member 12 is arranged in parallel with a tangential
direction to a installed in such an orientation that a longitudinal
direction thereof is aligned along with the rotational
circumferencetial direction of the brake disc. The base 12base
member 12 is made of a metal including an iron base material in
which iron is used as a base materialmain material.
The base 12base member 12 has a plurality of through holes
16 extending therethrough in a thickness direction thereof. The
through holes 16 are formed provided at locationpositions onat
which the friction blocks 14 are respectively mounted. TheA
number of the through holes 16 to be formed is the same as thea
number of the friction blocks 14 to be mounted. Each through hole
16 has an expanded outer opening in an outer portion (lower portion
of the base member 12 in FIG. 1) of the base member 12is formed
in such a shape that a lower portion thereof in FIG. 1 is made
to be larger in diameter.
The base 12base member 12 is formed withhas a curved seat
18 having a concave curved surface, which is formed in thea front
surface (upper surface of the base member 12 in FIG. 1) of the
base that faces thereof on thea friction block 14 side (in an upper
surface of the base 12 in FIG. 1) and around theeach through hole

16. The curved seat 18 is formed as a recess having a circular
shape in a plan view, and a curved upper surface of the base 12
in the recess is a seat surface 18a. The through hole 16 is open
at a center of the curved seat 18.
As shown in FIGS. 2A and 2B, theeach friction block 14 is
formed in the shape of a thick disc. Although not shown in the
drawings, Theeach friction block 14 may be formed in the shape
of a polygon such as a triangle, a pentagon, and a hexagon, and
the like. In this case, the vertices of the polygon may beare
preferably formed in a rounded shape.
The friction block 14 includes a reinforcing plate 21 which
serves as an example of a support member, and a friction member
23 which is fixedly attached to the reinforcing plate 21. The
friction block 14 has a through hole 25 extending through the
reinforcing plate 21 and the friction member 23. The reinforcing
plate 21 is made of a metal including an iron as a main material
base material in which iron is used as a base material. The
reinforcing plate 21 includes a circular plate-shaped bodymain
portion 27 in the shape of a circular plate, and an annular portion
29 which projectings from the mainbody portion 27. The through
hole 25 extends through a center portion of the mainbody portion
27. The annular portion 29 projects from the mainbody portion
27 around the through hole 25 toward the base 12base member 12.
The annular portion 29 is located so as to faces the curved seat
18.

The annular portion 29 has an end surface (a lower surface)
29a which is formed as a convexly curved surface so as to correspond
to the seat surface 18a of the concave curved seat 18 of the base
12base member 12. In other words, the end surface 29a of the
annular portion 29 agrees withis an arc of a circle ular arc
surface having a center located on an axis of the annular portion
29. The friction block 14 is mounted in a statelocated such that
a gap exists is formed between the end surface 29a of the annular
portion 29 and the seat surface 18a of the curved seat 18. When
the end surface 29a of the annular portion 29 comesis brought into
contact with the seat surface 18a of the curved seat 18, the end
surface 29a of the annular portion 29 is slidable over displaceable
on the curved seat 18 in this contacted state.
The friction member 23 is fixedly attachedprovided on to
thea surface (an upper surface in FIG. 1) of the reinforcing plate
21 that is remote fromopposite to the base 12base member 12. The
friction member 23 is formed in the shape of a thick disc, and
the through hole 25 extends through a center portion of the friction
member 23. The friction member 23 has the same shape as that of
the reinforcing plate 21 in a plan view.
The friction member 23 is made of a copper alloy including,
namely, a copper base material in which copper is used as a base
materialmain material, and . The friction member 23 is made of
a sintered material in which a small amounts of an additive, such
as a metals such as iron, metallic compounds such as iron, and/or

graphite and/or other additives, these elements being is dispersed
so as to obtain a high coefficient of friction even at high
temperature. The friction member 23 is sintered so as to be
thereby fixedly attached to the reinforcing plate 21. It is noted
that the friction member 23 is not limited to a member made of
a sintered metal, but may be made of, for example, a material
including in which reinforcement fiber is dispersed in a synthetic
resin which is a base materialmain material.
The friction member 23 has a freen end end surface (an end
surface on a side distant from the base 12base member 12 or; an
upper surface in FIG. 1) which servesis a friction surface 23a.
The friction surface 23a is to be pressed against the brake disc
(not shown), and isbecomes a slide a contact surface which is to
be brought into slide contact with the brake disc.
The through hole 25 of the friction block 14 has is formed
as a hole having a step which defines a narrow such that a diameter
space in of the through hole 25 closer to the on a base 12base
member 12 side is smaller than that on an end surface side.
SpecificallyIn other words, the through hole 25 includes a step
portion 25a, a small diameter portion 25b, and a large diameter
portion 25c. The step portion 25a is formed in the reinforcing
plate 21, and located between the small diameter portion 25b and
the large diameter portion 25c. The small diameter portion 25b
is located closer to formed on the base 12base member 12 side with
respect to the step portion 25a, and the large diameter portion

25c is located closer toformed on thea friction member 23 side
with respect to the step portion 25a.
The through hole 25 of the friction block 14 faces the through
hole 16 of the base 12base member 12. A, and a rivet 30 is inserted
in the through hole 16 of the base 12base member 12 and the through
hole 25 of the friction block 14 to thereby couple. Thus, the
friction block 14 14 is coupled to the base 12base member 12.
The rivet 30 includes a head 32 for preventing the rivet
30 from moving of f coming off, and a main body 34 which has a diameter
smaller than that of the head 32. The diameter of the head 32
is smaller than that of the large diameter portion 25c of the
through hole 25 of the friction block 14, and larger than that
of the small diameter portion 25b. The head 32 has a contact lower
ssurface coming intowhich is in contact with an upper surface (a
contact surface) of the step portion 25a of the through hole 25
of the friction block 14 to thereby . Thus, the rivet 30 prevents
the friction block 14 from movingcoming off.
The main body 34 includes a contact portion 34a coming which
is into contact with the base 12base member 12, and an intermediate
portion 34b which is located between the head 32 and the contact
portion 34a. The intermediate portion 34b has a diameter which
is smaller than those of the head 32 and the contact portion 34a.
In other words, the diameter of the contact portion 34a is larger
than that of the intermediate portion 34b.
The contact portion 34a has a diameter which is smaller than

that of the head 32 and is in contact at a lower part thereof with
the curved seat 18 of the base 12base member 12.
The main body 34 further includes a fastening portion 36
which extends from the lower part of the contact portion 34a and
is located in the through hole 16 of the base 12base member 12.
The fastening portion 36 is formed withhas an expanded lower part
which is made to be having a larger in diameter in the expanded
opening of the through hole 16 to thereby sandwich , and the rivet
30 is fixed to the base 12 by sandwiching the base 12base member
12 between the expanded lower part of the fastening portion 36
and the contact portion 34a.
A distance from the contactlower surface of the head 32 to
the contacta lower surface of the contact portion 34a is slightly
longer than that from the contactupper surface of the step portion
25a to thean end surface 29a of the annular portion 29. Thus,
in thea state where the friction block 14 is coupled to the base
12base member 12, there is a slight gap is formed between the end
surface 29a of the annular portion 29 and the seat surface 18a
of the curved seat 18.
An elastic member 40 is provided between the base 12base
member 12 and the friction block 14. The elastic member 40 is
a metallic disc spring which has a dish- shaped member which is
constructed of a metallic disc spring, and has an opening 40a at
a bottom thereof. The annular portion 29 is inserted in the
opening 40a of the elastic member 40, and the elastic member 40

is located between the base 12base member 12 and the friction block
14.
The elastic member 40 applies an elastic force to the base
12base member 12 and the friction block 14 in a direction of
separatingwhich causes the base 12base member 12 and the friction
block 14 to be separated from each other. The elastic member 40
has an elastic coefficient which allows such that the elastic
member 40 to beis elastically deformed when during a braking action
in which the friction block 14 is pressed against the brake disc
to perform braking. AccordinglyThus, the elastic member 40 is
elastically deformed by a pressing force transmitted to the
elastic member 40 through the friction block 14 when the friction
block 14 is pressed against the brake disc, which causes . As
a result, the friction block 14 to beis displaced in an up-down
direction, or to displaced at a tilt.
A heat transfer suppressing member 44 is provided between
the friction block 14 and the elastic member 40. The heat transfer
suppressing member 44 is made of a plate material having the
substantially the same shape and size as those of the base 12base
member 12 in a plan view.
The heat transfer suppressing member 44 is formed
withincludes a contact portions 44a which is provided in sections
corresponding to theeach plurality of friction blocks 14, and an
extension portion 44b extending which is provided between these
contact portions 44a. Each contact portion 44a is formed in an

annular shape having an inner diameter which is slightly larger
than an outer diameter of the annular portion 29, and having an
outer diameter which is slightly larger than that of an upper
portion (an outer circumferencetial portion) of the elastic member
40. The heat transfer suppressing member 44 is arranged in
provided on a lower surface of the friction block 14 such a way
that the annular portion 29 passesis inserted through an opening
of the contact portion 44a and . tThe contact portion 44a comes
is in contact with the friction block 14.
The extension portion 44b is formed so as to connects the
contact portions 44a with one another, to each other, andand the
extension portion 44b is bent on the outer periphery of the contact
portions 44a and extends in substantially parallel with the
friction block 14 while keeping a spacefrom each contact portion
44a in a stepped manner. Thus, the extension portion 44b is
separated from the lower surface of the friction block 14, and
extends in a direction parallel to the lower surface of the friction
block 14.
The heat transfer suppressing member 44 is made of a material
having a smaller coefficient of thermal conductivity which is
smaller than that of the friction block 14. For example, the heat
transfer suppressing member 44 is made of a stainless-steel plate
material having a smaller coefficient of thermal conductivity
which is smaller than that of a cast iron which the reinforcing
plate 21 a part (a lower part) of the friction block 14 on the

base 12 side is made of.
A plurality of projection portions 48 (six projections in
this embodimente drawing) areis provided in the friction block
14. Each projection portion 48 integrally includes a first
irregularity portion 48a, a second irregularity portion 48b, and
a head portion 48c. The first irregularity portion 48a is formed
withas an external thread which is at one end of the projection
portion 48 so as to be capable of being screwed into a threaded
hole 21a which is formed in the mainbody portion 27 of the
reinforcing plate 21. In other words, the projection portion 48
is formed with has a part with irregularities in a side surface
thereof. The first irregularity portion 48a has an end which
comesis into contact with the contact portion 44a of the heat
transfer suppressing member 44 and receives athe pushing elastic
force of the elastic member 40.
The second irregularity portion 48b is formed inat the other
portionend of the projection portion 48 and in a shape extendsing
in one direction. The second irregularity portion 48b is formed
with has wide width parts and narrow width parts which are arranged
alternately in a longitudinal direction thereof to thereby
increase the second irregularity portion 48b. Thus, athe
contact area of between the second irregularity portion 48b
withand the friction member 23 is increased, and thereby
preventing the friction member 23 from separating moving in a
direction in which the friction member 23 is separated from the

reinforcing plate 21. TIt is noted that the second irregularity
portion 48b may be formed withas an external thread as the first
portion 48a.
The head portion 48c is located between the first
irregularity portion 48a and the second irregularity portion 48b.
In the present embodiment, the head portion 48c is formed in the
shape of a head of a hexagon bolt head bolt.
The projection portion 48 is screwed into the threaded hole
21a of the reinforcing plate 21. In other words, the projection
portion 48 is fastenedfixed to the reinforcing plate 21 by a
mechanical fastenering means. The projection portion 48 is
inserted and screwed into the threaded hole 21a from the friction
member side side, and the head portion 48c of the projection portion
48 comesis into contact with thean upper surface of the reinforcing
plate 21 that is in contact with (a surface of the reinforcing
plate 21 on the friction member 23 side). In other words, the
projection portion 48 is arranged in provided such a way that the
head portion 48c more extending in a radial directionly and
outwardly thanfrom the first irregularity portion 48a projects
from the surface of the reinforcing plate 21 that is in contact
with on the friction member 23 side.
The projection portions 48 are arrangedprovided in such way
that their respective axes are parallel with so as to extend into
the friction member 23 in a direction perpendicular to the friction
surface 23a. The projection portions 48 extend to or near are

set to have such a height as to reach the vicinity of the friction
surface 23a of the friction member 23. Thus, even if when a crack
occuris generated in the friction member 23 by a shear force
generated at braking, the crack can be prevented from does not
developing further by the provisiondue to the existence of the
projection portions 48.
The friction member 23 is fixedly attached to the reinforcing
plate 21 after the projection portions 48 are fastened to the
reinforcing plate 21. SpecificallyIn other words, after the
projection portions 48 are mounted to the reinforcing plate 21,
the friction member 23 is sinteredly attached to the reinforcing
plate 21 and the projection portions 48. Thus, the second
irregularity portions 48b of the projection portions 48 isare
buried in the friction member 23. This reliably prevents the
projection portions 48 are kept from being loosening offed and
falling out.
In the sintering process whereWhen the friction member 23
is fixedly attached to the reinforcing plate 21 in a sintering
process, the friction member 23 is also firmly integrated
withfixed to the projection portions 48. The projection portions
48 are made of a copper alloy which includes base material in which
copper is used as a base materialmain material and which is similar
to the material of the friction member 23. Thereforeus, , in the
process wherewhen the friction member 23 is sintered, the friction
member 23 easily integrates withand the projection portions 48

are easily fused together. It is noted that as while the friction
member 23 is worn away at braking, the projection portions 48 are
similarly worn away at the samethis time.
There is a possibility that in the disc padbrake pad 10
according to the present embodiment, a crack occursis generated
in athe friction member 23 by a shear force received by the friction
member 23 at braking. However, even in this case, adevelopment
of range in which the crack develops is limited to a considerably
small extent by the projection portions 48. Even if when the
generated crack developsextends to an intermediate portion in the
friction member 23of the friction member 23 which is surrounded
by the projection portions 48 and causes the likelihood such that
the intermediate portion of the friction member 23 separates into
pieces toward the brake disc and the reinforcing plate 21 at the
intermediate portionis divided into a part on a friction surface
side and a part on a reinforcing plate side which are separable
from each other, even a piecethe part of the friction member 23
will be kept from going away because the friction member 23 is
firmly integrated with on the friction surface side is fixed to
the projection portions 48 each having the irregularities in the
side surface thereof, the friction member 23 is held by the
projection portions 48. SpecificallyIn other words, since the
projection portions 48 each have the irregularities in the side
surface thereof, which increases thea contact area of between the
friction member 23 withand the projection portions 48 is

increased, and the existence of tThe irregularities serve to
prevents the friction member 23 from moving in a direction of going
awayin which the friction member 23 is separated from the
reinforcing plate 21. As a result In this way, the integrationa
fixing strength ofbetween the friction member 23 withand the
projection portions 48 is high, andreinforced. Thus, the
friction member 23 is prevented from partially fallingbreaking
off or flying apart. In other words, the projection portions 48
prevent a crack from developing to such a degree that the friction
member 23 wholly breaksfalls off or flies apart, and further
prevent even a part of the friction member 23 from fallingbreaking
off or flying apart.
Especially, in the case thatwhen the disc padbrake pad 10
is applied to a high-speed rail vehicle, since frictional heat
of high temperature is generated, it is important to ensure a
sufficient coefficient of friction of the friction member 23 at
high temperature because the friction member 23 has a high
temperature due to frictional heat. The, and a type and an amount
of an additives are determinedselected from this viewpoint. For
this reasonThus, there may be a case of using a where the friction
member 23 which does not have a sufficient toughnesstenacity in
a high temperature region. Even in such thisa case, in the disc
padbrake pad 10 of the present embodiment, the provisionexistence
of the projection portions 48 prevents a crack from developing
to such a degree that the friction member 23 wholly breaksfalls

off, and further prevents even a part of the friction member 23
from fallingbreaking off or flying apart.
In addition, even in the case of selecting where a material
adapted for the friction member in view of a high-speed rail vehicle
and need of is selected as a material for the friction member 23
with a high coefficient of friction, in other words, even in the
case where the friction member does not have paramount in
consideration and has an insufficient toughnesstenacity as
compared with a material which is selected for the friction member
23 with tenacity paramount in consideration of a toughness of the
friction member, since the disc padbrake pad 10 of the present
embodiment prevents the friction member 23 from fallingbreaking
off, and the like due to development of a crack. This provides
a wider selectability of a material for the friction member in
aspects of , a degree of freedom in material selection, such as
types and amounts of additives, is increased.
Further, in the present embodiment, since the projections
portions 48 are fixedly attached to the reinforcing plate 21 by
the mechanical fastenering means, even a material s which are
unsuitable for connection with the reinforcing plate 21 difficult
to fuse together can be used selected for the reinforcing plate
21 and the projection portions 48. This enhances the
designability in aspect of us, a degree of freedom in design
regarding the material is improved. , and Tthe projection portions
48 can beare more firmly mounted to the reinforcing plate 21.

Further, in the present embodiment, since each projection
portion 48 is separately formed with includes the first
irregularity portion 48a and the second irregularity portion 48b,
the first irregularity portion 48a can be madeis set to have a
thread having a shape and a size of a thread which are best suited
for the connection with first irregularity portion 48a to be
fastened to the reinforcing plate 21, and the second irregularity
portion 48b can be madeis set to have a shape and a size of the
irregularities having a shape and a size best suited for the
connection with which make it easy for the friction member 23 to
be fixed to the second irregularity portion 48b. Thus, it is easy
to satisfy the contrary demands characteristics of fastening to
the reinforcing plate 21 and integrating withof fixing to the
friction member 23.
In addition, since the irregularities of the second
irregularity portion 48b located inon the friction member 23side
have the are larger irregularities fromin size than those of the
first irregularity portion 48a, it is unlikely that the first
irregularity portion 48a is not looseneddisengages from the thread
hole 21a due to vibrations, and other causes the like.
SpecificallyIn other words, since the second irregularity portion
48b willis not engage with screwed into the threaded hole 21a of
the reinforcing plate 21, the first irregularity portion 48a is
unlikely to not loosened by the existence of the second
irregularity portion 48bdisengage from the thread hole 21a.

AccordinglyAs a result, the projection portion 48 is reliably-
prevented from falling outdisengaging off. In addition, by making
the larger irregularities of the second irregularity portion 48b
larger in size than those of the first irregularity portion 48a
makes , the material of the friction member 23 easily entersreach
the cutsapertures of the irregularities of the second irregularity
portion 48b. Thus, it is possible to satisfy the contrary demands
characteristics of fastening to the reinforcing plate 21 and
ofintegrating with fixing to the friction member 23.
Further, in the present embodiment, since the projection
portions 48 and the friction member 23 are made of materials having
the same base materialmain material, the friction member 23 and
the projections portions 48 are easily integrated with each
otherfused together in the when manufacturing of the disc padbrake
pad 10 . This increasesus , the integration fixing strength between
the friction member 23 and the projection portions 48 is reinforced,
and the friction member 23 is more effectively prevented from
fallingbreaking off or flying apart.
TIt is noted that the projection portions 48 may be formed
to have such a height as to reach the friction surface 23a of the
friction member 23.
Further, although the disc padbrake pad 10 applied to a
high-speed rail vehicle has been described in the present
embodiment, the present invention is also applicable to vehicles
other than a high-speed rail vehicle.

Further, as shown in FIGS. 3, 4A, and 4B, aeach projection
portion 48 may be constructed byof a bolt. In this embodiment,
the projection portion 48 includes a threaded portion 48d and a
head portion 48e. A, and the threaded hole 21a which is formed
inof the a reinforcing plate 21 has a small diameter threaded
portion and a large diameter portion for receiving the head portion
48e of the projection portion 48 from athe base side. The
projection portion 48 is engaged with the small diameter threaded
portion of inserted in the threaded hole 21a and such that the
head portion 48e is in the large diameter portion of the hole 21a
of enters the reinforcing plate 21. AThe friction member 23 is
sintered after the projection portion 48 is screwed into the
reinforcing plate 21. ConsequentlyThus, the friction member 23
is fixedly attached to the reinforcing plate 21 and the threaded
portion 48d of the projection portion 48. Further, the head
portion 48e of the projection portion 48 receives the elastic force
of anthe elastic member 40 through athe heat transfer suppressing
member 44. TThus, an end of the projection portion 48 is pressed
by the pushing force of the elastic member 40. H, and hence, the
projection portion 48 which is mechanically fastened to the
reinforcing plate 21 is prevented from disengaging being loosened
due to vibrations, and other causesthe like. AccordinglyAs a
result, the projection portion 48 is reliably prevented from
fallingbreaking offout.
IEven in this embodiment, also, each projection portion 48

may be formed to have such a height as to reach the friction surface
23a of the friction member 23. Further, even this embodiment is
applicable to vehicles other than a high-speed rail vehicle.
[Summary of Embodiments]
The above embodiments are summarized as follows.
(1) In the present embodiment, there is a possibility that
a crack occursis generated in the friction member due toby a shear
force received by the friction member at braking. However, even
in this case, a range in which the development of the crack develops
is limited to a considerably small range by the projection portions .
Thus, the crack is prevented from developing throughout the
friction member. Further, even ifwhen a crack develops to an
extent of causing a likelihood is generated such that a part of
the friction member separates is divided into pieces toward a part
on the brake disc and friction surface side and a part on the support
member side which are separable from each other, the friction
member is firmly held by the projections since the friction member
is fixedly attached to the projection portions each having the
irregularities in the side surface thereof, and the
integrationfixing strength between the friction member and the
projection portions is highreinforced, and hence the friction
member is held by the projection portions. Thus, the friction
member is prevent from partially fallingbreaking off or flying
apart. In other words, the projection portions prevent a crack
from developing to such a degree that the friction member wholly

breaksfalls off or flies apart, and prevent the friction member
from partially fallingbreaking off or flying apart.
(2) The projection portions may be fixedly attached to the
support member by a mechanical fastenermeans.
In this constructionmode, a materials unsuitable for the
connection with the support member which are difficult to fuse
together can be used selected for the support member and the
projection portions. Thus, thea degree of freedom of selecting
a material in design regarding the material is improved. Also,
and the projection portions are firmly mounted to the support
member.
(3) The projection portions each may include athe first
irregularity portion which is formed withas an external thread
to be screwed into the support member, and athe second irregularity
portion which is firmly integrated with fixed to the friction
member.
In this constructionmode, the first irregularity portion
and the second irregularity portion are separately provided in
the projection portion, the first irregularity portion is formed
with set to have a shape and a size of a thread having a shape
and a size which are best suited for the connection with first
irregularity portion to be fastened to the support member, and
the second irregularity portion is is made with set to have a shape
and a size of irregularities which make it easysuitable for
integration with the friction member to be fixed to the second

irregularity portion. Thus, it is easy to satisfy the contrary
demands characteristics of fastening to the support member and
integratingfixing to with the friction member.
(4) The irregularities of the second irregularity portion
may be formed with irregularities having a larger cut in size than
those of the external thread of the first irregularity portion.
In this constructionmode, thea pitchnumber of crests of the
external thread (the first irregularity portion) which is screwed
into the thin plate-like support member having a small thickness
is shortenedincreased. Thus, the projection portions are more
firmly attached to the support memberfixed. On the other hand,
ifwhen the irregularities of the second portion have small cuts
number of the crests of the external thread is increased, the size
of the irregularities becomes small, and it is difficult for the
friction member is hard to enter the cuts apertures of the
irregularities due to the short pitch, making it difficult to
firmly hold the friction member., accordingly. Thus, the friction
member cannot be reliably fixed. However, in this
constructionmode, by making the irregularities of the second
irregularity portion have larger cutsin size than those of the
first irregularity portion make, the material of the friction
member easily enter the cutsapertures of the irregularities of
the second irregularity portion. Therefore, it is possible to
satisfy the contrary demands characteristics of fastening to the
support member and integrating of withfixing to the friction

member.
(5) The projection portions each may receive a pushing
force have on a base side an end which receives the force from
the elastic member at an outer end thereof.
In this constructionmode, since the end of each projection
portion receivesis pressed by the pushing force of the elastic
member, the projection portion which is mechanically fastened to
the support member is prevented from disengaging from the support
memberbeing loosened due to vibrations, and other causesthe like.
AccordinglyAs a result, the projection portion is reliably
prevented from disengaging offfalling out.
As described above, according to the present embodiment,
the disc padbrake pad effectively prevents the friction member
from even partially fallingbreaking off.

What is Claimed is
1. A disc padbrake pad to be pressed against a brake disc,
comprising:
a base member;
a friction block which includinges a support member, and
a friction member which is fixedly attached to a surface of the
support member, the friction block being mounted to the basebase
member;
an elastic member which is provided between the basebase
member and the friction block for allowing, the elastic member
pressing the friction block to tilt toward the brake disc and
so as to allow the friction block to move in a direction ofto
approaching the basebase member when the friction block is pressed
against the brake disc and so as to allow the friction member to
be displaced at a tilt; and
a plurality of projection portions which each project from
the surface of the support member to which the friction member
is fixedly attached, and the plurality of projection portions each
extendhaving such a height as to reach to a friction surface of
the friction member or a vicinity of the friction surface of the
friction member, and each have a rugged the plurality of projection
portions each having irregularities in a side surface thereof,
the plurality of projection portions being fixed to and the
friction member being firmly integrated with each other.

2. The disc padbrake pad according to claim 1, wherein the
plurality of projection portions are fixedly attached to the
support member by a mechanical fastenering means.
3. The disc padbrake pad according to claim 2, wherein the
plurality of projection portions each include a first irregularity
portion which is formed withas an external thread to be screwed
into the support member, and a second irregularity portion which
is fixedfirmly integrated with to the friction member.
4. The disc padbrake pad according to claim 3, wherein the
second irregularity portion has irregularitiesies which having
a larger cut in size than those of the external threadfirst
irregularity portion.
5. The disc padbrake pad according to claim 2, wherein the
plurality of projection portions each have on a base side an end
which receives a pushing force from the elastic member at an outer
end thereof.

AThe disc padbrake pad 10 includes an elastic member 40 which is provided between a base 12base member 12 and a friction block 14 and which allowspresses the friction block 14 toward the brake disc so as to allow the friction block 14 to tilt and move in a direction to approaching the base 12base member 12 when the
friction block is pressed against the brake discand so as to allow a friction member 23 to be displaced at a tilt, and a plurality
of projection portions 48 which project from a surface of a reinforcing plate 21 to which athe friction member 23 is fixedly attached, and extendeach of which has such a height as to reach
to the vicinity of a friction surface 23a of the friction member 23 and have irregularities in a rugged side surface thereof., and which are fixed to The projections 48 and the friction member 23 are firmly integrated with each other. The disc padbrake pad 10 can effectively prevents the friction member 23 from even
partially fallingbreaking off.