JPH11173352A - Brake element with wear indicator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To freely mount a hold cylinder for supporting and fixing a wear indicator on a brake shoe assembly after a brake lining and a back plate are mutually connected and fixed. SOLUTION: A main part 29 of a hold cylinder 8b is like a knotched circular cylinder, and an outside diameter thereof can be elastically and freely expanded and shrunk. When the hold cylinder 8b is mounted on a brake shoe assembly 1, a diameter of the main part 29 is elastically shrunk. Locking collar parts 30, 30 formed at a tip fringe of the main part 29 are engaged with a locking stepped part 33 provided in a boundary part between a brake lining 3 and a back plate 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A brake element with a wear indicator according to the present invention is incorporated in a drum brake or a disk brake used for braking an automobile as a brake shoe assembly for a drum brake or a pad for a disk brake. Use it in the condition. Then, when the brake lining is worn with use, a signal is issued to an alarm device for prompting replacement of the brake element. In this specification, the term "brake element" refers to a general term for a brake shoe assembly and a pad. Conversely, in this specification, a brake shoe assembly refers to a brake element for a drum brake, and a pad refers to a brake element for a disc brake.

[0002]

2. Description of the Related Art For example, a brake shoe assembly 1 as shown in FIG. 23 is incorporated in a drum brake for braking an automobile. The brake shoe assembly 1 has a brake lining 3 attached and fixed to an outer peripheral surface of a brake shoe 2. Brake shoe 2 of these
A metal plate having a sufficient rigidity, such as a steel plate, is formed in a roughly crescent shape on the outer peripheral edge of the web 4. Composed and fixed. The drum brake is constructed by arranging a pair of the above-described brake shoe assemblies 1 diametrically inside a bottomed cylindrical drum (not shown) that rotates together with the wheels. When braking, the above 1
The pair of brake shoe assemblies 1 are displaced radially outward of the drum by sending pressure oil to a wheel cylinder (not shown), and press the outer peripheral surface of the brake lining 3 against the inner peripheral surface of the drum, The braking force is exerted on the basis of the frictional force acting between these two peripheral surfaces.

[0003] Brake shoe assembly 1 as described above
Of the brake lining 3 is gradually worn by repeated braking. Therefore, when the wear has progressed to a certain extent, the brake shoe assembly 1 must be replaced with a new one. However, the brake lining 3
Since it is impossible to visually determine the thickness of the wear indicator from the outside, a sensor called a wear indicator is attached to the brake shoe assembly 1, and when the brake lining 3 is worn to an allowable limit, the wear indicator A command is issued from the alarm device provided in the driver's seat based on the signal from the driver to prompt the exchange of the brake shoe assembly 1.

FIG. 24 shows a first example of a conventionally known pad with a wear indicator described in Japanese Utility Model Laid-Open Publication No. 5-47562, which has been considered in order to achieve such an object. At the end of the back metal 5a constituting the pad 6,
In the part protruding from the periphery of the brake lining 3a,
A mounting hole 7 penetrating the back metal 5a is formed, and a metal holding cylinder 8 is mounted inside the mounting hole 7. A step 9 is formed on the inner peripheral surface of the intermediate portion of the holding cylinder 8, and a substantially J-shaped locking notch 10 is formed on the edge. The wear indicator 11 includes a lead wire 1 serving as a detection unit in a holder 12 made of phenol resin or the like which is a thermosetting resin.
3 is buried. Further, on the side surface of the base end portion of the wear indicator 11, the above-mentioned locking notch 1 is provided.
A locking pin 14 which can freely enter the inside of the housing is protruded.

When the above-mentioned wear indicator 11 is mounted on the back metal 5a, first, a compression spring 15 is inserted into the inside of the holding tube 8 mounted on the mounting hole 7, and then the holding indicator 8 is inserted into the holding tube 8. The wear indicator 11 is inserted from the back side of the back metal 5a. Then, between the step 16 formed on the outer peripheral surface of the wear indicator 11 and the step 9 of the holding cylinder 8, the compression pin 15 is compressed while the locking pin 14 is locked. Let go into the back. As shown in FIG. 24, in a state in which the locking pin 14 has been inserted deep into the locking notch 10, the locking pin 14 may come out of the locking notch 10 due to the elasticity of the compression spring 15. Then, the wear indicator 11 is firmly supported by the back metal 5a. In this manner, with the wear indicator 11 supported by the back metal 5a, the tip of the conducting wire 13 is located on the wear allowable limit surface X of the brake lining 3a.

When the brake lining 3a wears due to repetition of braking and its thickness decreases,
First, the tip of the holder 12 is worn by friction with the disk 17. When the wear further proceeds, this holder 1
The tip of the wire 13 buried in 2 rubs against the side surface of the disk 17, and the wire 13 breaks at the tip. The breakage of the conductive wire 13 is detected by a detection circuit (not shown), which sends a signal to an alarm provided in the driver's seat and issues a command to prompt the replacement of the pad 6 by the alarm.

Next, FIGS. 25 and 26 show actual Japanese Patent Publication No. 58-42.
No. 665 discloses a second example of a conventionally known pad with a wear indicator. This second
In the case of the example structure, the holding cylinder 8a is supported and fixed in a mounting hole 7 formed in a part of the back metal 5a to which the brake lining 3a is attached. The holding cylinder 8a is formed in a cylindrical shape by a metal plate, and has a tip portion (FIGS. 25 to 26).
An outer flange is formed with an outward flange-shaped flange portion 18a on the outer peripheral edge, and a plurality of claw pieces 19, 19 are provided on the inner peripheral surface of the intermediate portion. Each of these claw pieces 19, 19 is formed by bending the inside of a U-shaped cut having an open front end toward the inner diameter side of the holding cylinder 8a.
Are inclined in the direction in which the amount of protrusion from the inner peripheral surface increases.
The flange 18a is sandwiched between the surface of the back metal 5a and the back of the brake lining 3a.

On the other hand, the holder 12a of the wear indicator 11a supported and fixed inside the holding cylinder 8a as described above is
The large diameter portion 20 on the distal side and the small diameter portion 21 on the proximal side are
Has a shape that is continuous. The outer diameter of the large diameter portion 20 is
The diameter of the inscribed circle of the tip edge of the plurality of claw pieces 19 in the free state is larger than the diameter. Also, at the base end,
An outward flange-shaped locking flange 23 is formed. In order to support and fix such a holder 12a inside the holding cylinder 8a, the holder 12a is placed inside the holding cylinder 8a and the large diameter portion 2 is fixed.
Push in with 0 first. With the pushing operation, the large-diameter portion 20 enters the front end side of the holding cylinder 8a while elastically deforming the claw pieces 19, 19. Then, with the holder 12a fully pressed into the holding cylinder 8a,
The claw pieces 19, 19 are elastically restored, and the leading edge of each of the claw pieces 19, 19 and the step 22 are engaged, and at the same time, the base edge of the holding cylinder 8a and the locking flange 23 abuts. In this state, the holder 12a is
a.

[0009]

In the case of the first example of the conventional structure shown in FIG. 24, the operation of supporting and fixing the holding cylinder 8 to the back metal 5a is troublesome, and the cost increases. When the wear indicator 11 is supported and fixed to a portion of the back metal 5a to which the brake lining 3a is attached, in order to prevent the brake lining 3a from interfering with the caulking portion of the holding cylinder 8a. Need to form a through hole,
To that extent, the friction area of the brake lining 3a is reduced. Further, when the back metal 5a and the brake lining 3a are connected and fixed by rivets, the holding cylinder 8 is easily damaged at the time of the connection and fixing. After the back metal 5a and the brake lining 3a are connected and fixed, it is difficult to support and fix the holding cylinder 8 to the back metal 5a.

Further, the second structure of the conventional structure shown in FIGS.
In the case of the example, the operation of connecting and fixing the brake lining 3a and the back metal 5a and the operation of supporting and fixing the holding cylinder 8a to the back metal 5a must be performed simultaneously. After the brake lining 3a and the back metal 5a are connected and fixed, even if the user forgets to assemble the holding cylinder 8a, it is impossible to assemble the holding cylinder 8a later unless the brake lining 3a and the back metal 5a are disassembled. It is. In addition, when the brake lining 3a and the back metal 5a are connected and fixed by rivets, the holding cylinder 8a may be damaged. For this reason, the yield of the brake element to which the holding cylinder 8a is assembled is deteriorated.

As a structure for supporting and fixing a holding tube for supporting and fixing a wear indicator to a backing metal constituting a brake element, other than this, for example, Japanese Utility Model Publication No. 6-11382.
Japanese Unexamined Patent Publication (Kokai) No. H10-264, pp. 157-334 is known. According to the structure described in this publication, after the brake lining and the back metal are connected and fixed, the holding cylinder can be supported and fixed to the back metal. However, in the case of the structure described in Japanese Utility Model Publication No. Hei 6-11382, the shape of the holding tube is complicated and the manufacturing cost of the holding tube is increased, and the holding tube is supported and fixed among the back metal. The portion that can be formed is limited to a position deviating from the portion where the brake lining is attached. In view of the above-described circumstances, the brake element with a wear indicator of the present invention can freely support and fix the holding cylinder to a portion of the backing to which the brake lining is attached, and furthermore, it is difficult to damage the holding cylinder, and the brake lining The invention has been devised in order to realize a structure in which the holding and fixing operation of the holding cylinder can be performed after the connecting and fixing operation of the holding cylinder and the back metal.

[0012]

A brake element with a wear indicator according to the present invention comprises, similarly to a conventionally known brake element with a wear indicator, a back metal, a brake lining attached to the surface of the back metal, and It has a mounting hole that penetrates the back metal, a cylindrical holding cylinder supported and fixed inside the mounting hole, and a wear indicator having a detection unit embedded in the holder. Then, the wear indicator is inserted into the holding cylinder, and is supported by the backing metal in a state where the detection unit is positioned on the wear allowable limit surface of the brake lining.

In particular, in the brake element with a wear indicator according to the present invention, the inner diameter of the mounting hole is formed at the boundary between the back metal surface and the back surface of the brake lining around the opening of the mounting hole. Also have a large diameter locking step. Also, the holding cylinder is made of an elastic material,
A cylindrical main part having a discontinuous part at one location in the circumferential direction;
Outer diameter regulating means provided at a portion of the main part in the axial direction protruding from the mounting hole to prevent the outer diameter of the main part from expanding, and diametrically outward from the leading edge of the main part. And a locking flange portion bent. The locking flange can pass through the mounting hole in a state where the diameter of the main portion is reduced.

[0014]

The operation when braking is performed by the brake element with a wear indicator of the present invention configured as described above, and the operation when an alarm is issued when the brake lining is worn to an allowable limit are described above. It is the same as the attached brake element. In particular, in the case of the brake element with a wear indicator of the present invention, the engaging step and the engaging flange formed around the opening of the mounting hole at the boundary between the back metal surface and the back surface of the brake lining are engaged. The holding cylinder can be supported and fixed to the portion of the back metal to which the brake lining is attached. In addition, since the operation of engaging the locking step and the locking flange can be performed after the back metal and the brake lining are connected and fixed, the holding cylinder is hardly damaged, and the connection between the brake lining and the back metal is performed. After the connecting and fixing operation, the supporting and fixing operation of the holding cylinder can be performed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 17 show a first embodiment of the present invention. In the illustrated example, the wear indicator 11b of the same type is used to change the inner diameter of the insertion hole 24 formed in the brake lining 3 so that the position of the wear allowable limit surface X of the brake lining 3 can be changed. The structure is shown. The brake shoe assembly 1 has a brake lining 3 on an outer peripheral surface of a back metal 5 which constitutes the brake shoe 2 together with the web 4.
Are fixedly attached by rivets 25. A mounting hole 7 a is formed in a part of the back metal 5 so as to penetrate the back metal 5. The insertion hole 24 is formed in a part of the brake lining 3 which is aligned with the mounting hole 7a. The insertion hole 24 is concentric with the mounting hole 7a and has a smaller diameter than the mounting hole 7a. 1, 2, and 1 are provided inside the mounting hole 7 a and the insertion hole 24.
Wear indicator 1 as shown at 0, 11, 15-17
1b is attached. The basic structure of the wear indicator 11b is the same as the wear indicator 12 used in the conventional structure shown in FIG. That is, the wear indicator 11b is formed by burying a detection unit such as the conductor 13 (see FIG. 24) in a holder 12b made of a synthetic resin. The brake element with a wear indicator according to the present embodiment includes a holder 12b for the wear indicator 11b,
The holder 12b is inserted into the mounting hole 7a, and a portion of the holder 12b near the front end (the upper end of FIGS. 1, 2, 10, 11, 15 to 17) is inserted into the insertion hole 24, and the front end of the detection unit is connected to the front end. The brake lining 3 is supported on the back metal 5 in a state where the brake lining 3 is located on the wear allowable limit surface X.

The first half of the holder 12b (FIGS. 1, 2, 1)
The outer diameter of the upper half (0, 11, 15 to 17) is thinner at a portion closer to the distal end and thicker at a portion closer to the proximal end. That is, the holder 12b has a base half (FIGS. 1, 2, 10, 11, 15 to 15).
17 (a lower half part), and a relatively large diameter main part 26 constituting a first half part, and a relatively small diameter insertion part 27 constituting a first half part. The conducting wire 14 constituting the detection section is embedded in the insertion section 27. In the case of this example, the outer diameter of the insertion portion 27 is made thinner at a portion closer to the distal end and thicker at a portion closer to the proximal end. For this reason, in the case of the present example, a step portion 28 is formed in the middle portion of the insertion portion 27, and the outer diameter of a portion closer to the front end is smaller than the step portion 28, and the main portion 26 is smaller than the step portion 28. The outside diameter of the shifted part is increased.

In the case of this embodiment, the holder 12b of the wear indicator 11b as described above is fixed to the mounting hole 7a without increasing the amount of protrusion of the back metal 5 from the inner peripheral surface. In order to facilitate the attachment / detachment work of 11b, inside of the mounting hole 7a,
A holding cylinder 8b formed in a cylindrical shape by a metal plate having elasticity and corrosion resistance such as a stainless steel plate is fixed. The holding cylinder 8b used in this example is integrally formed of an elastic metal plate, such as stainless steel spring steel.
A main portion 29 having a cylindrical shape is provided. Locking flanges 30, 30 are provided at two positions on the opposite side of the distal end edge of the main portion 29 in the circumferential direction.
Is formed by bending a part of the metal plate constituting the holding cylinder 8b outward at right angles in the diameter direction. On the other hand, a locking flange 31 is provided on the base end edge of the main portion 29,
Except for the discontinuous portion of the main portion 29, the main portion 29 is formed over the entire circumference or intermittently in the circumferential direction. Then, the main portion 29 sandwiched between the locking flange portions 30 and 30 and the locking flange 31 is formed.
A short cylindrical holding ring 32 is fitted around the intermediate portion.
The pressing ring 32 corresponds to an outer diameter restricting means of the present invention. The inner diameter of the pressing ring 32 is different from the outer diameter of the holding cylinder 8b in a use state (a state in which the holder 12b is assembled inside). Are matched.

On the other hand, as shown in FIG. 6, an insertion hole 24 and a mounting hole 7a are formed in the brake lining 3 and the back metal 5 constituting the brake shoe assembly 1 for supporting and fixing such a holding cylinder 8b. ing. A locking step 33 is formed on the surface of the back metal 5 at the periphery of the opening of the mounting hole 7a.
Is formed over the entire circumference. The inner diameter of the insertion hole 24 is regulated in relation to the outer diameter of the insertion portion 27 of the holder 12b described above. On the other hand, the inner diameter of the mounting hole 7a and the diameter of the locking step 33 are determined by the main portion 29 of the holding cylinder 8b.
And the diameter of the circumcircle of the locking flanges 30, 30. That is, as shown in FIG. 4, when the diameter of the holding cylinder 8b expands elastically and the outer peripheral surface of the intermediate portion of the holding cylinder 8b and the inner peripheral surface of the holding ring 32 are in close contact with each other, the locking is performed. The diameter of the circumscribed circle of the flanges 30, 30 is equal to the diameter of the mounting hole 7a.
, But smaller than the diameter of the locking step 33. On the other hand, as shown in FIG. 5, when the discontinuous portion of the main part 29 constituting the holding cylinder 8b is closed and the diameter of the holding cylinder 8b including the main part 29 is reduced to a minimum, the locking The diameter of the circumscribed circle of the flanges 30, 30 is set to be equal to or less than the inner diameter of the mounting hole 7a. In the illustrated example, in order to make the back surface of the brake lining 3 and the surface of the back metal 5 closely contact each other, these two surfaces and the respective locking flanges 3 are provided.
A locking step portion 33 for preventing interference with 0 and 30 is provided on the outer peripheral surface side of the back metal 5. However, such a locking step 33 may be provided on the inner peripheral surface side of the brake lining 3. If the locking step 33 is provided on the brake lining 3 side, the locking step 33 can be formed at the same time when the brake lining 3 is formed, so that the cost can be reduced.

The holding cylinder 8b as described above is fixedly supported on the back metal 5 after the brake lining 3 is attached and fixed to the back metal 5. That is, when manufacturing a brake element with a wear indicator having the structure of the present example, first, the brake lining 3, the back metal 5, and the rivet 25 are combined as shown in FIG. 6, and then as shown in FIG. To form a brake shoe assembly 1. Next, as shown in FIG. 8, the holding cylinder 8b is approached from the back side of the brake shoe assembly 1. At this time, the diameter of the holding cylinder 8b is elastically reduced as shown in FIG. In this way, the locking flanges 30, 30 provided on the holding cylinder 8b are inserted into the mounting holes 7a. Then, the holding cylinder 8 is held in a state where the locking flanges 30 are positioned diametrically inside the locking step 33.
Release the force that reduced the diameter of b. As a result, as shown in FIG.
3 and is engaged therewith, so that the holding cylinder 8b does not come out of the mounting hole 7a. At the same time, this holding cylinder 8b
A portion of the outer peripheral surface of the main portion 29 near the front end contacts the inner peripheral surface of the mounting hole 7a, and a portion near the base end also contacts the inner peripheral surface of the holding ring 32. Therefore, in the state shown in FIG. 9, the rigidity of the holding cylinder 8b against the outward force in the diametrical direction of the cross section is sufficiently high. For this reason, the holder 12 of the wear indicator 11b has a structure as described below.
Even when b is held inside the holding cylinder 8b, the supporting strength of the holder 12b can be sufficiently ensured.

The holder 12b of the wear indicator 11b, which is supported and fixed to the brake shoe assembly 1 as described above, can be held and fixed inside the holding cylinder 8b. , A plurality of (for example, 2 to 4) claw pieces 34, 34 are formed to project at equal intervals in the circumferential direction. Each of the claw pieces 34, 34 is formed on a part of an elastic metal plate constituting the holding cylinder 8b, and the inside of a long U-shaped cutout opening at the tip end of the holding cylinder 8b is formed inside the holding cylinder 8b. It is formed by bending slightly to the peripheral surface side. The above-mentioned claw pieces 34, 3 configured in this manner
Reference numeral 4 denotes a direction in which the amount of protrusion from the inner peripheral surface of the holding cylinder 8b is increased (a direction inward of the holding cylinder 8b in the diameter direction).
, And is inclined in such a direction that the amount of protrusion increases toward the brake lining 3 in a free state.

On the other hand, a second step portion 35 is formed at the axially intermediate portion of the holder 12b and functions as an abutting portion projecting outward in the diametrical direction. That is, the main part 2
6, the outer diameter of the portion close to the insertion portion 27 is made larger than the outer diameter of the portion away from the insertion portion 27, and the second step portion 35 is formed at the connecting portion between these two portions. ing.

An inner sleeve 36 is externally fitted to a part of the holder 12b as described above, which is closer to the base end than the second step 35. The inner sleeve 36 is made of a metal plate or a synthetic resin plate having elasticity and corrosion resistance such as a stainless steel plate or the like, and is formed in a partially cylindrical shape so that the diameter can be elastically expanded and contracted. Also, this inner sleeve 3
Locking portions 37, 37 protruding outward in the diametric direction are provided at two positions on the diametrically opposite side of the base end edge portion 6 respectively.

Further, the inner sleeve 36 is made of a metal plate or a synthetic resin plate having elasticity and corrosion resistance, such as a stainless steel plate, and is formed in a cylindrical shape so that the diameter is elastically expandable and contractible. 38 is fitted outside. The axial dimension of the outer sleeve 38 is larger than the axial dimension of the inner sleeve 36. or,
The inner and outer peripheral surfaces of the outer sleeve 38 are formed with knurling or the like to form unevenness in the axial direction. Accordingly, of the inner and outer peripheral surfaces of the outer sleeve 38, the inner peripheral surface is frictionally engaged with the outer peripheral surface of the inner sleeve 36, and the outer peripheral surface is engaged with the leading edges of the claw pieces 34, 34. Further, the outer sleeve 38 has elasticity in a direction of reducing the diameter in a free state.

The operation of attaching and fixing the wear indicator 11b to the back metal 5 using the components described above is performed as follows. As described above, the holding cylinder 8b is fixed to the back metal 5 after the brake shoe assembly 1 is manufactured. In the first step of the mounting and fixing work, first, the wear indicator 11
b is inserted into the holding cylinder 8b with the insertion portion 27 first. In order to perform this insertion operation, the nail 3
4 and 34, these claw pieces 34 and 34
The notches 39, 39 that can pass through the
In the axial direction.

When the holder 12b is inserted into the holding tube 8b as described above, the inner space is inserted into the cylindrical space 40 between the inner peripheral surface of the holding tube 8b and the outer peripheral surface of the holder 12b. The sleeve 36 and the outer sleeve 38 are pushed in. Prior to the pushing operation, the outer sleeve 38 is fitted over the inner sleeve 36, and these two sleeves 36, 38 are simultaneously pushed into the cylindrical space 40. When the outer sleeve 38 is externally fitted to the inner sleeve 36, the outer sleeve 38 is elastically expanded in diameter. The pushing operation is performed at least until the leading edge of the outer sleeve 38 abuts on the second step 35. More preferably, each of the locking portions 37, 3
7 until it comes to the base end of the outer sleeve 38.

When the pushing operation is performed to this state, the inner sleeve 36 holds the base end of the holder 12b, and the outer sleeve 38 holds the inner sleeve 36. Then, the outer sleeve 38 is connected to the second step portion 35 and the locking portions 37, 3
7 to prevent the outer sleeve 38 from moving in the axial direction with respect to the holder 12b. Further, the outer sleeve 38 is prevented from falling out of the holding cylinder 8b based on the engagement between the outer peripheral surface of the outer sleeve 38 and the claws 34, 34. Further, the inner sleeve 36 includes inner and outer peripheral surfaces, the outer peripheral surface of the holder 12b, and the outer sleeve 3.
8 is firmly supported by the frictional force acting between the inner peripheral surface 8 and the inner peripheral surface. As a result, the holder 12b is attached to the back metal 5
Can be firmly supported and fixed. The static force based on the frictional force acting between the respective peripheral surfaces is sufficiently larger than the thrust load applied to the holder 12b from the inner peripheral surface of the brake drum during braking in a state where the brake lining 3 is worn. Big.

As described above, the holder 12 is
According to the structure for supporting and fixing b, the amount by which the base end of the wear indicator 11b and the member for supporting and fixing the wear indicator 11b protrude from the inner peripheral surface of the back metal 5 can be reduced. That is, as is clear from the above description, the member for fixing the holder 12b inside the holding cylinder 8b fixed to the back metal 5 is pushed into the holding cylinder 8b, so that at the time of completion of the support fixing work, Each of these members slightly protrudes from the holding cylinder 8b. Therefore, as described above, the amount by which the wear indicator 11b and the member for supporting and fixing the wear indicator 11b protrude from the inner peripheral surface of the back metal 5 can be reduced. On the other hand, the holder 1 of the wear indicator 11 is attached to the back metal 5a by the conventional structure shown in FIG.
When 2 is mounted, the amount of protrusion of the base end of the wear indicator 11 from the inner peripheral surface of the back metal 5a increases.

Further, if the holder 12b is supported and fixed to the back metal 5 by the structure as in this embodiment, the work of removing the wear indicator 11b from the back metal 5 can be easily performed. The operation of removing the wear indicator 11b from the back metal 5 is performed as shown in FIGS. First, as shown in FIG. 15, the inner sleeve 36 is
Pull out from the cylindrical space 40. Since the inner and outer peripheral surfaces of the inner sleeve 36 are not particularly provided with locking portions such as irregularities, the locking portions 37 can be pulled out relatively easily by applying a strong force to the locking portions 37 in the pulling-out direction.

When the inner sleeve 36 is pulled out of the cylindrical space 40, the diameter of the outer sleeve 38 is elastically reduced, and the irregularities formed on the outer peripheral surface of the outer sleeve 38 and the claw pieces 34, 34 Disengagement from the leading edge. Then, when the notches 39, 39 formed in the holder 12b are aligned with the claws 34, 34, the holder 12b is pulled out from the holding cylinder 8b, and the wear indicator 11b is removed from the back metal 5. Can be separated. The work of pulling out the holder 12b from the holding cylinder 8b while aligning the notches 39, 39 with the claws 34, 34 is performed by operating a harness 44 derived from the wear indicator 11b. Easy to do.

If the leading edge of each of the claws 34, 34 and the outer peripheral surface of the outer sleeve 38 can be securely engaged, the outer peripheral surface of the outer sleeve 38 is necessarily formed with irregularities. No need. For example, the holding cylinder 8b provided with the claw pieces 34, 34 is made of a hard metal plate such as a stainless steel spring, and the outer sleeve 38 is formed.
Is made of a soft metal such as copper, brass or aluminum, or a synthetic resin, so that the tip edges of the claws 34, 34 bite into the outer peripheral surface of the outer sleeve 38.
The above unevenness becomes unnecessary. Further, it is not necessary to abut the locking portions 37, 37 against the base edge of the outer sleeve 38 in a state where the assembly is completed. Similarly, the inner and outer peripheral surfaces of the inner sleeve 36 and the outer sleeve 3
If the frictional force between the inner peripheral surface of the inner sleeve 8 and the outer peripheral surface of the base half of the holder 12b can be sufficiently ensured and the inner sleeve 36 can be sufficiently prevented from coming off, the inner peripheral surface of the outer sleeve 38 can be removed. No irregularities are required.

In the illustrated example, as described above, the position of the wear allowable limit surface X of the brake lining 3 can be changed by using the same type of wear indicator 11b. For this purpose, the inner diameter of the insertion hole 24 formed in the brake lining 3 is adjusted in relation to the outer diameter of the insertion portion 27 of the holder 12b in accordance with the desired position of the wear allowable limit surface X. That is, when the above-mentioned allowable wear limit surface X is installed at a position close to the outer peripheral surface of the back metal 5 (to reduce the allowable wear limit thickness of the brake lining 3), as shown in FIGS. 24 has a relatively small diameter. More specifically, the inside diameter of the insertion hole 24 is larger than the outside diameter of the insertion portion 27 near the distal end, and smaller than the outside diameter of the base portion near the base end. In this state, the holder 12
b is inserted into the mounting hole 7a and the insertion hole 24 from the inner peripheral surface side of the back metal 5, the step portion 28 formed in the intermediate portion of the insertion portion 27 forming the first half of the holder 12b is inserted. It hits the opening edge of the hole 24. In this state, the distance L ₁ (FIG. 1) from the outer peripheral surface of the back metal 5 to the wear allowable limit surface X (the allowable wear limit thickness of the brake lining 3) is determined from the end surface of the main portion 26 to the wear allowable limit. Surface X
Than the distance L ₀ to decreases from the end face by a distance △ L min until the stepped portion _{28 (L 1 = L 0 -} △ L).
Incidentally, even in a state where the outer peripheral surface has a small distance L ₁ to the wear tolerance limits plane X of the back metal 5 in this manner, the outer periphery of the brake lining 3 than the wear allowable limit surface X is a head of the rivet 25 It is needless to say that it is present on the side (on the upper side of FIGS. 1-2 and 15-16).

On the other hand, when the allowable wear surface X is set relatively far from the outer peripheral surface of the backing metal 5 (to increase the allowable wear thickness of the brake lining 3), FIG. As shown, the insertion hole 24 has a relatively large diameter. More specifically, the inner diameter of the insertion hole 24 is larger than the outer diameter of the portion near the base end of the insertion portion 27 and smaller than the outer diameter of the main portion 26. When the holder 12b is inserted into the mounting hole 7a and the insertion hole 24 from the inner peripheral surface side of the back metal 5 in this state, the end face of the main portion 26 abuts on the opening edge of the insertion hole 24. In this state, the distance L ₂ from the outer peripheral surface of the back metal 5 to the wear tolerance limits plane X, said wear tolerance limits plane X from the end face of the main portion 26
It becomes equal to the distance L ₀ to (L ₂ = L _0).

As described above, the wear indicator 11b
When the brake lining 3 is worn to an allowable limit as a result of repeated braking by a drum brake incorporating the brake shoe assembly 1 equipped with the brake shoe assembly 1, the conducting wire 13 (see FIG. 24) constituting the detection section is broken,
Raise an alarm. The function of issuing an alarm in this manner is the same as that of the above-described conventional brake element with a wear indicator. In particular, in the case of the present invention, the locking step 33 and the locking flange 30 formed around the opening of the mounting hole 7a at the boundary between the front surface of the back metal 5 and the back surface of the brake lining 3. , 30 are engaged with each other, so that
Of these, the holding cylinder 8b can be supported and fixed to the portion where the brake lining 3 is attached. Moreover, the operation for engaging the locking step 33 with the locking flanges 30, 30 is as follows.
This can be performed after the back metal 5 and the brake lining 3 are connected and fixed, so that the holding cylinder 8b is hardly damaged, and
After the work of fixing and fixing the brake lining 3 and the back metal 5, the work of supporting and fixing the holding cylinder 8 b can be performed. Therefore,
Even if the work of assembling the holding cylinder 8b is forgotten during the work of fixing the brake lining 3 and the back metal 5, the wear indicator 11b cannot be assembled to the brake shoe assembly 1.

Further, in the case of the example shown in the figure, the amount of protrusion of the wear indicator 11b from the back metal 5 can be kept small, and the work of removing the wear indicator 11b from the back metal 5 can be easily performed. Further, the operation of adjusting the position of the wear allowable limit surface X of the brake lining 3 is performed by inserting the insertion hole 2 into the brake lining 3.
Only by changing the inner diameter of 4, it can be performed without special processing of each component. Therefore, the wear limit surface X
Can effectively reduce the manufacturing cost of a plurality of types of brake shoe assemblies with wear indicators having different positions.

Next, FIGS. 18 to 21 show a second example of the embodiment of the present invention. In the case of this example, a tongue piece 41 is formed so as to protrude in the circumferential direction from one end in the circumferential direction of the holding cylinder 8c formed of a metal plate having elasticity and formed in a partially cylindrical shape. On the other hand, a guide portion 42 for slidably inserting an intermediate portion of the holding tongue piece 41 is formed on the outer peripheral surface of the other end in the circumferential direction of the holding cylinder 8c. This guide section 42
At the other end in the circumferential direction of the holding cylinder 8c, a portion between a pair of cuts formed at intervals in the axial direction of the holding cylinder 8c and in the circumferential direction is directed toward the outer peripheral surface. It is formed by extruding in a gate shape. The holding tongue piece 41
In the state in which such a guide portion 42 is inserted, the leading end thereof is turned 180 degrees outward in the diametrical direction of the holding cylinder 8c to form a locking portion 43.

The holding cylinder 8c as described above also has a brake shoe assembly 1 in which the brake lining 3 and the back metal 5 are connected and fixed in advance, as shown in FIG. As shown in FIG. 20, approach from the back side in a state where the diameter is elastically reduced, and each of the locking flanges 30, 3
0 is inserted into the mounting hole 7a, and each of the locking flanges 3 is inserted.
0, 30 and the locking step 33 are engaged. In the case of the present example, along with such an engagement work, a portion of the outer peripheral surface of the main body portion of the holding cylinder 8c near the front end contacts the inner peripheral surface of the mounting hole 7a, and at the same time, the locking portion 43 And the guide section 42
Engages with one side edge. Then, in this state, the rigidity of the holding cylinder 8c against the outward force in the diameter direction of the cross section is increased. Other configurations and operations are the same as those of the above-described first example.

FIG. 22 shows a third embodiment of the present invention. In the case of this example, a retaining ring 32a made of a coil spring, which is an outer diameter regulating means, is provided around the intermediate portion of the main portion 29 constituting the holding cylinder 8b. The configuration and operation of the portion other than the coil spring used as the retaining ring 32a are the same as those of the first example described above, and therefore, the same portions are denoted by the same reference numerals, and redundant description will be omitted.

In each of the above embodiments, the present invention has been described in the case where the present invention is applied to a brake shoe assembly for a drum brake. The structure of the illustrated embodiment has an effect that, when applied to a brake shoe assembly for a drum brake, a wear indicator can be installed in a limited space. However, the present invention is not limited to the above-described brake shoe assembly for a drum brake, but can also be applied to a pad for a disc brake. Further, a feature of the present invention resides in a portion for supporting and fixing the holding cylinder to the back metal. The structure of the wear indicator that is supported and fixed to the backing metal via the holding tube and the structure of coupling the wear indicator to the holding tube are not limited to those shown in the drawings, and various structures including the conventional structure described above are employed. it can.

[0039]

Since the present invention is constructed and operated as described above, the holding cylinder can be supported and fixed to a portion of the back metal to which the brake lining is attached, and the holding cylinder is hardly damaged, and the brake is not damaged. It is possible to realize a structure capable of performing the work of supporting and fixing the holding cylinder after the work of fixing the lining and the back metal.

[Brief description of the drawings]

FIG. 1 is a view showing an example of a first embodiment of an embodiment of the present invention and corresponding to an enlarged cross section AA in FIG. 23;

FIG. 2 is an enlarged view of a portion B in FIG.

FIG. 3 is a perspective view of a holding cylinder.

FIG. 4 is a side view showing the same in a free state.

FIG. 5 is a side view showing a state in which the diameter is elastically reduced.

FIG. 6 is a sectional view showing components of the brake shoe assembly in a state before coupling.

FIG. 7 is a cross-sectional view similarly showing a state in which it is fixedly connected.

FIG. 8 is a sectional view showing a state in the middle of an operation of connecting the holding cylinder to the brake shoe assembly.

FIG. 9 is a cross-sectional view showing a state in which the parts are similarly connected.

FIG. 10 shows only the wear indicator and FIGS.
The figure seen from the same direction as 2.

FIG. 11 is a view as viewed from above in FIG. 10;

FIG. 12 is a view of the inner sleeve as viewed from above in FIGS.

FIG. 13 is a view of the outer sleeve as viewed from above in FIGS.

FIG. 14 is a sectional view taken along line CC of FIG. 13;

FIG. 15 is a sectional view showing a first step of an operation of removing the wear indicator from the brake shoe assembly.

FIG. 16 is a sectional view showing the second step.

FIG. 17 is a view similar to FIG. 1, showing another example of an implementation state of the first example of the embodiment of the present invention;

FIG. 18 is a perspective view of a holding cylinder, showing a second example of the embodiment of the present invention.

FIG. 19 is a side view showing the same in a free state.

FIG. 20 is a side view showing a state where the diameter is elastically reduced.

FIG. 21 is a sectional view taken along the line DD in FIG. 19;

FIG. 22 is a view similar to FIG. 2, showing a third example of the embodiment of the present invention.

FIG. 23 is a schematic side view of a brake shoe assembly.

FIG. 24 is a sectional view of a main part showing a first example of a conventional structure.

FIG. 25 is a cross-sectional view of a holding cylinder installation portion that constitutes the second example.

FIG. 26 is a sectional view showing a state where the wear indicator is assembled.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brake shoe assembly 2 Brake shoe 3, 3a Brake lining 4 Web 5, 5a Back metal 6 Pad 7, 7a Mounting hole 8, 8a, 8b, 8c Holding cylinder 9 Step 10 Locking notch 11, 11a, 11b Wear indicator 12 , 12a, 12b Holder 13 Conductor 14 Locking pin 15 Compression spring 16 Step 17 Disk 18 Flange 19 Claw piece 20 Large diameter section 21 Small diameter section 22 Step 23 Locking flange 24 Insertion hole 25 Rivets 26 Main part 27 Insertion Part 28 Step part 29 Main part 30 Locking flange part 31 Locking flange 32, 32a Retaining ring 33 Locking step part 34 Claw piece 35 Second step part 36 Inner sleeve 37 Locking part 38 Outer sleeve 39 Notch 40 Cylindrical Shaped space 41 Holding tongue 42 Guide part 43 Locking part 44 Harness

Claims (1)

[Claims] 1. A backing metal, a brake lining attached to a surface of the backing metal, a mounting hole penetrating the backing metal, a cylindrical holding cylinder supported and fixed inside the mounting hole, and detection in a holder. A wear indicator having a buried portion, and the wear indicator is inserted into the holding cylinder, and the detection portion is supported by the back metal in a state where the detection portion is positioned on a wear allowable limit surface of the brake lining. In the brake element with the wear indicator, a locking step having a diameter larger than the inner diameter of the mounting hole is provided around the opening of the mounting hole at a boundary between the surface of the back metal and the rear surface of the brake lining. The holding cylinder is made of an elastic material, and has a cylindrical main part having a discontinuous portion at one location in the circumferential direction, and protrudes from the mounting hole at a part of the main part in the axial direction. Part An outer diameter restricting means for preventing the outer diameter of the main part from expanding, and a locking flange bent radially outward from a leading edge of the main part. A brake element with a wear indicator, wherein the part is capable of passing through the mounting hole with the diameter of the main part reduced.