JP2016080120A - Drum brake shoe and drum brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a structure of a brake shoe which can effectively make compatible the reduction of a manufacturing cost, the improvement of the work efficiency of lining exchange work, and the prevention of the generation of brake noise.SOLUTION: A rim part 26a and a lining 27a constituting a brake shoe 16a are fixed to each other with a plurality of rivets 12b, and an external peripheral face of the rim part 26a and an internal peripheral face of the lining 27a are bonded to each other with a resin-made attenuation member 28. The bonding position of the attenuation member 28 should be only a portion which is displaced from a portion for inserting the rivets 12b, which is also a portion corresponding to a belly part related to a vibration mode in reference to 2 kHz with a drum brake device as an object which is assembled with the brake shoe in which the lining 27a is fixed to the rim part 26a, and which does not comprises the attenuation member by using only the rivets 12b.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a drum brake shoe that is pressed against an inner peripheral surface of a drum that rotates together with a wheel and brakes the wheel, and an improvement of a drum brake device including the drum brake shoe.

  In order to brake a vehicle, various types of drum brake devices have been conventionally used for the reason that a large braking force can be obtained by exerting a self-boosting action. FIG. 17 shows a two-leading (single-acting) drum brake device 1 having a conventional structure. In a drum brake device 1 having a conventional structure, two wheel cylinders 3 and 3 are fixed to the front surface (the outer surface in the width direction of the vehicle) of a backing plate 2 that does not rotate while being supported by a suspension device such as a knuckle. . During braking, pressure oil is fed into each of the wheel cylinders 3 and 3 to increase the amount of protrusion of the pistons 4 and 4 fitted in the oil cylinders 3 and 3 in an oil-tight manner. A pair of brake shoes 5 and 5 are supported on the front surface of the backing plate 2 so as to be able to be displaced in the diameter direction of the backing plate 2. Each of the brake shoes 5 and 5 has arc plate-like rim portions 7 and 7 fixed to the outer periphery of the substantially crescent-shaped webs 6 and 6, and linings 8 and 8 are attached to the outer peripheral surfaces of the rim portions 7 and 7. It is attached.

  Both ends of the webs 6 and 6 constituting the brake shoes 5 and 5 in the circumferential direction (longitudinal direction) are formed at the tip of the pistons 4 and 4 or the ends of the wheel cylinders 3 and 3, respectively. The anchor portions 9 are in contact with the anchor portions 9. Further, return springs 10 and 10 are spanned between the two webs 6 and 6 to give elasticity to the brake shoes 5 and 5 inward in the diameter direction of the backing plate 2. . Further, a cylindrical drum 11 with a bottom is disposed around the brake shoes 5 and 5, and the inner peripheral surface of the drum 11 and the outer peripheral surfaces of the linings 8 and 8 are opposed to each other.

  At the time of non-braking, the inner peripheral surface of the drum 11 and the outer peripheral surface of each of the linings 8 and 8 are separated from each other through a gap. The braking force is exerted by the acting frictional force. That is, at the time of braking, the amount of protrusion of each piston 4, 4 is increased by feeding pressure oil into each wheel cylinder 3, 3, and each brake shoe 5, 5 is connected to each return spring 10, 10. The backing plate 2 is displaced outwardly in the diameter direction against elasticity, and the two peripheral surfaces are brought into contact with each other.

  Further, at the time of braking, there is a shear between the inner peripheral surfaces of the linings 8 and 8 constituting the brake shoes 5 and 5 and the outer peripheral surfaces of the rim portions 7 and 7 to which the linings 8 and 8 are attached. A strong force acts in the direction. Therefore, in order to prevent the linings 8 and 8 from being peeled off from the rim parts 7 and 7 regardless of the force in the shearing direction, as shown in FIG. Are coupled by a plurality of rivets 12 and 12. Specifically, the rivets 12 and 12 are respectively inserted into the rim portion through holes 13 and 13 and the lining side through holes 14 and 14 formed in the rim portion 7 and the lining 8 from the radially outer side. The lining 8 is coupled to the rim portion 7 by being inserted in the direction (from the upper side to the lower side in FIG. 18) and caulking the respective radial inner ends (lower end portions in FIG. 18).

However, when the brake shoe of the first example having the conventional structure as described above is used, a brake is caused by vibration of a minute gap generated between the inner peripheral surface of the lining and the outer peripheral surface of the rim during braking. There was a case where an abnormal noise called squeal was generated.
Therefore, various structures have been proposed in the past in order to prevent the generation of abnormal noise generated as described above. FIG. 19 shows a brake shoe 5a of a second example of a conventional structure described in Patent Document 1. In the case of the brake shoe 5a, the outer peripheral surface of the rim portion 7a and the inner peripheral surface of the lining 8a are bonded to each other by a damping member 15 that is a rubber adhesive. Specifically, in the outer peripheral surface of the rim portion 7a, the attenuation is applied to portions (slanted lattice portions in FIG. 19) that are out of the rim portion side through holes 13a, 13a formed to insert the rivets 12a, 12a. The member 15 is applied in a lattice shape (ladder shape). The lining 8a is overlapped so as to sandwich the damping member 15, and the lining 8a and the rim portion 7a are coupled by the rivets 12a and 12a.

  According to the brake shoe 5a of the second example of the conventional structure having such a configuration, the damping member 15 provided in a lattice shape causes a gap between the outer peripheral surface of the rim portion 7a and the inner peripheral surface of the lining 8a. It is possible to suppress the transmission of vibration. Therefore, it is possible to suppress the occurrence of brake squeal as compared with the first example of the conventional structure in which such a damping member is not interposed.

However, in the case of the second example of the conventional structure as described above, there is still room for improvement in the following points.
That is, in the case of the second example of the conventional structure, the outer peripheral surface of the rim part and the inner peripheral surface of the lining are bonded over a wide range by the lattice-shaped attenuation member. This increases the amount and increases the manufacturing cost of the brake shoe. For example, during regular inspections of the vehicle, lining replacement work has been widely performed, such as removing the worn lining from the outer peripheral surface of the rim and attaching a new lining. Since the outer peripheral surface of the rim portion and the inner peripheral surface of the lining are bonded over a wide range by a damping member, the work of removing the worn lining becomes troublesome, and the work efficiency of the lining reworking work is reduced. Furthermore, when a brake shoe that does not include a damping member between the outer peripheral surface of the rim portion and the inner peripheral surface of the lining is used as a reference, there is a possibility that a change in the vibration natural value (natural frequency) of the brake shoe becomes large. . For this reason, there is a possibility that a brake squeal having a frequency different from that of the brake squeal, which is a problem with the brake shoe not including the damping member, may occur.

Japanese Utility Model Publication No. 64-31224 JP-A-8-283532 JP-A-8-277354

  In view of the circumstances as described above, the present invention provides a drum brake shoe structure capable of effectively coexisting with a reduction in manufacturing cost, an improvement in work efficiency of lining reworking work, and prevention of brake squeal. It was invented to realize.

Of the drum brake shoe and drum brake device according to the present invention, the invention relating to the drum brake shoe is used by being incorporated in the drum brake device, and is an arc plate-like rim portion provided on the outer peripheral edge of the web. In addition, a lining which is a friction material is fixed by using a plurality of fixing tools (for example, rivets, bolts, nuts, etc.).
In the drum brake shoe of the present invention, a damping member made of, for example, a polymer material (rubber, thermoplastic elastomer, etc.) is sandwiched between the outer peripheral surface of the rim portion and the inner peripheral surface of the lining. The installation position of the damping member is regulated as follows.
That is, it is a part that is disengaged from the part where each of the fixing tools is inserted (disconnected in the circumferential direction and the width direction), and the lining is fixed to the rim portion using only these fixing tools. A vibration mode (for example, an abdomen and a node having a radial amplitude in the circumferential direction or a width direction) in a predetermined squeal frequency (for example, 2 kHz) for a drum brake device incorporating a drum brake shoe that does not sandwich a damping member. With respect to vibration modes and vibration patterns that appear alternately, the damping member is provided only in at least one portion corresponding to the abdomen.
When the present invention is implemented, the target squeal frequency is not limited to 2 kHz, and can be appropriately selected from 0 to 16 kHz which is a general audible range of human beings.

The vibration mode related to a predetermined squeal frequency is a state where the brake squeal is actually generated in the drum brake device. For example, when attention is paid to the squeal frequency of 2 kHz, the radial amplitude generated in the shoe for the drum brake is shown. This refers to a vibration waveform in which the abdomen and the node appear alternately in the circumferential direction or (and) the width direction. In the present specification and claims, unless otherwise specified, the abdomen is not only the top where the amplitude (displacement) is the largest, but also its vicinity {for example, the magnitude of the amplitude is the amplitude of the top. The range including 0.8 times (more preferably, 0.9 times or more) of the size}.
In addition, the thickness dimension (diameter direction thickness dimension) of the said attenuation member in the state clamped between the outer peripheral surface of the said rim | limb part and the inner peripheral surface of the said lining is about 0.05-0.5 mm, for example Can be.

When the disk brake shoe of the present invention as described above is implemented, the damping member includes, for example, a resole resin, a vinyl phenolic resin, a nitrile phenolic resin, or the like, as in the invention described in claim 2. It is comprised from the adhesive agent which is the resin composition to perform (in the state before hardening, for example, it is liquid or semi-solid form). And the outer peripheral surface of the said rim | limb part and the inner peripheral surface of the said lining are mutually adhere | attached by such a damping member.
In addition, when comprising the said attenuation | damping member from an adhesive agent, the kind in particular is not ask | required and what is generally marketed {for example, a hamatite (brand name)} can be used, As a specific material, for example, What was described in patent document 2, 3 etc. can be used.

Or, for example, as in the invention described in claim 3, the damping member is a plate material such as a rubber plate or a film material such as a rubber film or a synthetic resin film which does not have adhesiveness (adhesiveness). I can do things.
When adopting such a configuration, the damping member can be simply sandwiched between the outer peripheral surface of the rim portion and the inner peripheral surface of the lining (pinched without sticking), It can also be attached to at least one peripheral surface of the outer peripheral surface of the rim portion and the inner peripheral surface of the lining by an adhesive seal or the like provided separately from the damping member.

When the disc brake shoe of the present invention is implemented, the shape of the damping member (installation shape when viewed from the radial direction) is not particularly limited. For example, as in the invention described in claim 4, the drum A belt shape extending in the width direction of the brake shoe (axial direction of the drum) or, as described in claim 5, extended in the circumferential direction of the drum brake shoe (longitudinal direction, circumferential direction of the drum) It can be a band shape.
Alternatively, as in the invention described in claim 6, the damping member includes a widthwise belt-like portion extending in the width direction of the drum brake shoe and a circumferential belt-like portion extending in the circumferential direction of the drum brake shoe. These can be combined at right angles to form, for example, a cross shape, an L shape, a T shape, or the like.

The invention according to the drum brake device of the present invention includes a backing plate, a pair of shoes, a drum, and an expansion / contraction device.
Among these, the backing plate is supported and fixed to a structural member of a suspension device such as a knuckle.
The two shoes are supported at two positions opposite to the backing plate in the radial direction so as to be capable of displacement in the radial direction of the backing plate.
The drum is provided so as to cover both the shoes and rotates together with the wheels.
The expansion / contraction device is provided between the webs constituting both shoes in order to expand / contract the distance between the two shoes.
Particularly in the case of the drum brake device of the present invention, the drum brake shoe of the present invention is used as at least one of the two shoes.

According to the drum brake shoe and the drum brake device of the present invention having the above-described configuration, it is possible to reduce the manufacturing cost, improve the work efficiency of the relining work of the lining, and prevent the occurrence of brake squeal (abnormal noise). , Can be side by side effectively.
That is, also in the case of the present invention, the damping member is sandwiched between the outer peripheral surface of the rim portion and the inner peripheral surface of the lining as in the case of the second example of the conventional structure described above. Particularly in the case of the drum brake, the installation position of the damping member is a part that is disengaged from the part through which the fixing tool is inserted, and the lining is fixed to the rim part using only these fixing tools. In the drum brake device incorporating the shoe for use, only the portion corresponding to at least one abdominal portion with respect to the vibration mode related to a predetermined squeal frequency is used.
Thus, in the case of the present invention, since the damping member is installed only in the portion corresponding to the abdomen where the displacement amount increases with respect to the vibration mode (vibration waveform) relating to the predetermined squeal frequency, Compared to the two examples, the installation area (installation range) of the attenuation member can be reduced.
Therefore, since the amount of the attenuation member used can be reduced, the manufacturing cost can be reduced.
In addition, it is possible to easily remove the worn lining from the outer peripheral surface of the rim portion, so that the work efficiency of the lining reworking operation can be improved.
Furthermore, in the case of the present invention, the part corresponding to the abdomen where the amount of displacement is large, which is the occurrence site of the brake squeal, is sandwiched with the damping member, so despite the small amount of the damping member used, Brake noise can be suppressed. Further, since the amount of use of the damping member can be suppressed, it is possible to prevent the vibration eigenvalue of the brake shoe from changing greatly. Therefore, according to the present invention, it is possible to effectively prevent the occurrence of a brake squeal having a frequency different from that of the brake squeal, which is a problem in the brake shoe with no damping member interposed.

The front view which shows the drum brake apparatus of the 1st example of embodiment of this invention. The front view which shows the state which removed the drum similarly. Similarly perspective view. The front view which takes out and shows a brake shoe similarly. Similarly, a plan view (A) and a bottom view (B). Similarly left side (A) and right side view (B). Similarly AA sectional drawing of FIG. Similarly perspective view. The schematic diagram which isolate | separates and shows the brake shoe and the vibration mode regarding the frequency of 2 kHz similarly. The expanded view of the outer peripheral surface of a lining shown in order to demonstrate the installation position of a damping member similarly. The figure equivalent to FIG. 10 which shows the 2nd example of embodiment of this invention. The figure which shows a 3rd example and corresponds to FIG. The figure corresponding to Drawing 10 showing the 4th example similarly. The schematic diagram which shows nine examples of the application position and application shape of the attenuation member which can be employ | adopted when implementing this invention. The schematic diagram which shows another four examples similarly. Furthermore, the schematic diagram which shows another 4 examples. The front view of the drum brake device provided with the shoe for drum brakes of the 1st example of the conventional structure. Similarly BB sectional drawing. The disassembled perspective view which shows the shoe for drum brakes of the 2nd example of conventional structure.

[First example of embodiment]
A first example of the embodiment of the present invention will be described with reference to FIGS. The drum brake device 1a of the present example is a double-acting type two-leading drum brake device that can obtain a high braking efficiency and a stable braking efficiency in both cases of forward travel and reverse travel. For example, it is provided on the rear wheel of the vehicle.

The drum brake device 1a of this example mainly includes a backing plate 2a, a drum 11a, a pair of wheel cylinders 3a and 3b, a pair of brake shoes 16a and 16b, and a pair of return springs 10a and 10a. I have.
In the case of this example, the direction indicated by the arrow X in FIG. 2 indicates the rotation direction (forward direction) of the drum 11a when the vehicle moves forward, and the direction indicated by the arrow Y is the vehicle. The direction of rotation (reverse direction) of the drum 11a during reverse movement is shown.

  The backing plate 2a is made of, for example, a metal plate such as an aluminum alloy and has a substantially disk shape. The backing plate 2a is formed with a fitting insertion hole 17 for inserting an axle and a plurality of bolt holes 18, 18. It is supported by a suspension device (vehicle body) such as a knuckle and does not rotate.

  The drum 11a is made of, for example, a metal such as cast iron and has a substantially bottomed cylindrical shape. The drum 11a is supported by a hub unit fixed to an axle in a state of being concentrically arranged with the backing plate 2a, together with wheels. Rotate. The drum 11a covers the brake shoes 16a and 16b while being supported by the hub unit.

  Each of the wheel cylinders 3a and 3b corresponds to the expansion / contraction device described in the claims. The front and rear direction of the vehicle (FIG. 2) is provided on the front surface (the outer surface in the width direction of the vehicle) of the backing plate 2a. 3 in the left-right direction). Each of the wheel cylinders 3a and 3b has a substantially cylindrical shape with both axial ends opened, and a connecting pipe (not shown) is attached to each axial intermediate portion and communicates with the master cylinder. Thereby, pressure oil (brake oil) can be supplied from the master cylinder into the wheel cylinders 3a and 3b. A pair of pistons 4a and 4b are oil-tightly fitted in the wheel cylinders 3a and 3b in such a state that they are arranged in opposite directions with respect to the axial direction. For this reason, at the time of braking, pressure oil is supplied to a portion between the pistons 4a and 4b among the wheel cylinders 3a and 3b. It is a direction to expand and is displaced in the vertical direction in FIGS.

  In the case of this example, adjuster mechanisms 19, 19 are provided for adjusting the distance between the circumferential ends of the brake shoes 16a, 16b. For this purpose, adjuster gears 20 and 20 having external teeth on the outer peripheral surface are disposed at the tip ends of the pistons 4a and 4a that are present downstream of the pistons 4a and 4b in the forward rotation direction of the drum 11a. These pistons 4a and 4a are supported so as to be capable of relative rotation. Further, the amount of protrusion from each piston 4a, 4a can be adjusted by rotating each adjuster gear 20, 20 to the inner diameter side of each adjuster gear 20, 20 at the tip of each piston 4a, 4a. In addition, adjuster screws 21 and 21 are provided. Further, gear stoppers 22 and 22, which are partially engaged with the outer teeth of the adjuster gears 20 and 20, are fixed to the outer peripheral surfaces of the wheel cylinders 3 a and 3 b by bolts 23 and 23, respectively. The adjuster gears 20 and 20 are prevented from rotating carelessly. In the case of this example, by rotating these adjuster gears 20 and 20 in a predetermined direction and increasing the protruding amount of the adjuster screws 21 and 21, the distance between the circumferential ends of the brake shoes 16a and 16b is increased. Expand. The clearance between the outer peripheral surface of each of the linings 27a and 27b and the inner peripheral surface of the drum 11a is kept constant regardless of the progress of wear of the linings 27a and 27b of the brake shoes 16a and 16b. ing.

  The brake shoes 16a and 16b are separated from each other in the vertical direction of the vehicle on the front surface of the backing plate 2a by shoe hold springs 24 and 24, respectively, in the diameter direction of the backing plate 2a (up and down in FIGS. Is elastically supported to allow displacement in the direction). Such brake shoes 16a, 16b have arc plate-like rim portions 26a, 26b fixed to the outer peripheral edges of substantially crescent-shaped webs 25a, 25b, and friction materials are provided on the outer peripheral surfaces of these rim portions 26a, 26b. Some linings 27a and 27b are attached. Of the webs 25a and 25b constituting the brake shoes 16a and 16b, one end in the circumferential direction (the end on the upstream side in the forward rotation direction) is the tip of each piston 4a and 4a (adjuster screws 21 and 21). The other end in the circumferential direction (end on the downstream side in the forward rotation direction) is engaged with the tip of each of the pistons 4b and 4b. Further, the outer peripheral surfaces of the linings 27a and 27b, which are partially cylindrical surfaces having the same curvature as the inner peripheral surface of the drum 11a, are opposed to the inner peripheral surface of the drum 11a. Further, the return springs 10a and 10a are bridged between the webs 25a and 25b constituting the brake shoes 16a and 16b, respectively, and the inside of the backing plate 2a in the diametrical direction with respect to the brake shoes 16a and 16b. Gives the elasticity toward the direction.

  The overall structure of the drum brake device 1a of the present example is as described above. Next, the structure of each brake shoe 16a, 16b, which is a characteristic part of the present example, will be described in detail. In the case of the example, the brake shoe 16a provided on the upper side and the brake shoe 16b provided on the lower side have the same configuration (such as being rotated 180 degrees with respect to the central axis of the backing plate 2a) except that the arrangement positions thereof are different. In the following description, only the brake shoe 16a provided on the upper side is targeted.

  The brake shoe 16a of the present example has the rim portion 26a, the lining 27a, and the lining portion 27a in a state where the damping member 28 is held at a predetermined position in a portion between the outer peripheral surface of the rim portion 26a and the inner peripheral surface of the lining 27a. Are connected by rivets 12b and 12b. For this purpose, the rim portion 26a is provided with rim portion side through holes 29, 29, which are circular holes penetrating in the radial direction, in the width direction (the direction parallel to the axial direction of the drum 11a, and the vertical direction in FIG. 5). ) Are divided into two rows, and each row is formed at a plurality of intervals (six in the example shown in the figure, 12 in total in the circumferential direction) in the circumferential direction (left-right direction in FIG. 5). The lining 27a also has two rows of lining side through holes 30, 30 which are circular holes (stepped circular holes) penetrating in the radial direction in the width direction (vertical direction in FIG. 5 and horizontal direction in FIG. 6). In each row, a plurality (6 in the circumferential direction, 12 in total in the illustrated example) are formed at equal intervals in the circumferential direction (left and right direction in FIG. 5, up and down direction in FIG. 6). The diameters of the rim portion side through holes 29 and 29 are smaller than the diameters of the lining side through holes 30 and 30. The rim portion side through holes 29 and 29 and the lining side through holes 30 and 30 communicate with each other in the radial direction in the state where the lining 27a is superimposed on the outer peripheral surface of the rim portion 26a. It is formed in the position to do.

  In this example, the rim 27a is bonded to the outer peripheral surface of the rim portion 26a (or the inner peripheral surface of the lining 27a or both peripheral surfaces) before the lining 27a is overlaid on the outer peripheral surface of the rim portion 26a. The damping member 28, which is an agent, is applied. The damping member 28 is made of a resin composition containing, for example, a resole resin, a vinyl / phenolic resin, a nitrile phenolic resin, or the like, and is in a liquid or semi-solid state when applied (a state before curing). In the case of this example, the application position (installation position) of such an attenuation member 28 is restricted to a position that satisfies both the following first and second conditions.

  First condition: A portion of the outer peripheral surface of the rim portion 26a that is out of the rim portion side through holes 29, 29 in the width direction and the circumferential direction.

Second condition: a brake shoe not provided with a damping member in which the lining 27a is fixed to the rim portion 26a using only the rivets 12b and 12b (a brake shoe that is the same as the brake shoe 16a of this example except for the presence or absence of the damping member 28) As for the arbitrarily selected vibration mode for 2 kHz for drum brake devices that incorporate, only the part corresponding to the abdomen.
When only the brake shoes 16a and 16b are replaced with the brake shoes not provided with the damping member 28 from the drum brake device 1a of this example, and the brake squeal is actually generated, Various frequency components are included. Then, when the vibration mode is simulated for 2 kHz, which makes it easy for the vehicle occupant to feel unpleasant noise from such frequency components, the abdomen of the radial amplitude as shown in FIG. A vibration waveform in which the node portions appear alternately in the circumferential direction is obtained. Therefore, in the case of this example, three abdominal portions (Pa, Pb, Pc) are selected from the abdominal portions that have appeared, and correspond to the appearance position of the abdominal portion in the circumferential direction on the outer peripheral surface of the rim portion 26a. The attenuating member 28 is applied only to the portion to be applied.
In the case of this example, the abdomen includes not only the apex having the largest amplitude but also a range in which the amplitude is 0.9 times or more the amplitude of the apex.

  In the case of this example, the application position and application shape of the damping member 28 are as shown in FIG. 10 when viewed from the outside in the radial direction of the brake shoe 16a. That is, a total of four lining side through holes 30, 30 (rim part side through holes 29, 29) between the circumferential center position (Xa) and the circumferential center position of the outer peripheral surface of the rim part 26a. Attenuating members 28 are respectively applied in a band shape at a total of three positions including positions (Xb, Xc) near both ends in the circumferential direction across the).

More specifically, the damping member 28 has a constant circumferential dimension W ₂₈ and a width dimension L ₂₈ longer than the circumferential dimension W ₂₈ (L ₂₈ > W ₂₈ ). The strip shape is elongated. Moreover, the circumferential dimension W _28, smaller than the circumferential length W ₃₀ between portions of the pair of lining side holes 30, 30 adjacent to each other in the circumferential direction (for example, about 1 / 3-1 / 2 To). Further, in the case of this example, the circumferential dimension W _{28 is set} to ½ of the circumferential width W ₁₅ (see FIG. 19) related to the damping member 15 in the second example of the conventional structure. It is about. Thus, a portion where the damping member 28 is not applied is provided between the edge in the width direction of the damping member 28 and the opening of each lining side through hole 30, 30. The width direction dimension L ₂₈ is set smaller than the dimension L _{27 in} the width direction of the lining 27a (rim portion 26a). Thereby, the part which does not apply | coat this attenuation member 28 is provided in the width direction both sides part of the said attenuation member 28. As shown in FIG.

  After the damping member 28 is applied to the position as described above on the outer peripheral surface of the rim portion 26a, the rim portion side through holes 29, 29 and the lining side through holes 30, 30 are in the radial direction. The lining 27a is overlapped from the outside in the radial direction so as to communicate with each other. In this state, the damping member 28 is cured, and the damping member 28 adheres the outer peripheral surface of the rim portion 26a and the inner peripheral surface of the lining 27a to each other at the application position. In addition, the thickness dimension (diameter direction thickness dimension) of the said attenuation | damping member 28 in the hardened state will be about 0.05-0.5 mm, for example. In addition, after the lining 27a is overlaid, the rivets 12b and 12b are respectively inserted into the rim side through holes 29 and 29 and the lining side through holes 30 and 30 from the radially outer side to the inner side. The lining 27a is coupled to the rim portion 26a by being inserted toward (downward and downward in FIG. 7) and caulking each radial inner end (lower end in FIG. 7).

  In the case of the drum brake device 1a of the present example having the above-described configuration, when the driver operates the brake pedal in a state where the vehicle is moved in the forward direction (X direction in FIG. 2), each of the above-mentioned items from the master cylinder. Pressure oil is supplied into the wheel cylinders 3a and 3b, and the pistons 4a and 4b fitted to the wheel cylinders 3a and 3b are displaced in directions away from each other. In particular, of these two wheel cylinders 3a and 3b, the piston 4a fitted to one of the wheel cylinders 3b presses the brake shoe 16a disposed above the inner peripheral surface of the drum 11a, and the other wheel cylinder 3a. The piston 4a fitted to the urging member presses the brake shoe 16b disposed below the inner peripheral surface of the drum 11a. At this time, the piston 4b fitted to the one wheel cylinder 3b and the piston 4b fitted to the other wheel cylinder 3a each function as an anchor. Thereby, the outer peripheral surfaces of the linings 27a and 27b constituting the brake shoes 16a and 16b are brought into pressure contact with the inner peripheral surface of the drum 11a, and a frictional force is generated between the two peripheral surfaces. And by this frictional force, the rotation of the drum 11a is decelerated, and the rotation of the wheel is decelerated.

On the other hand, when the vehicle is moved in the reverse direction (Y direction in FIG. 2), the piston 4b fitted to one of the wheel cylinders 3a and 3b is moved downward. The disposed brake shoe 16b is pressed against the inner peripheral surface of the drum 11a, and the piston 4b fitted to the other wheel cylinder 3a presses the brake shoe 16a disposed above against the inner peripheral surface of the drum 11a. At this time, the piston 4a fitted to the one wheel cylinder 3b and the piston 4a fitted to the other wheel cylinder 3a each function as an anchor. Thereby, the outer peripheral surfaces of the linings 27a and 27b constituting the brake shoes 16a and 16b are brought into pressure contact with the inner peripheral surface of the drum 11a, and a frictional force is generated between the two peripheral surfaces. And by this frictional force, the rotation of the drum 11a is decelerated, and the rotation of the wheel is decelerated.
Thus, in the case of the drum brake device 1a of the present example, since it is configured as a double-action type two-leading type, the two brake shoes 16a and 16b are attached in both cases of forward movement and reverse movement. Since each of them can function as a leading shoe, it is possible to obtain a sufficient braking force both when moving forward and when moving backward.

In particular, according to the drum brake device 1a of this example, it is possible to effectively reduce the manufacturing cost, improve the work efficiency of the lining 27a, 27b reworking work, and prevent the occurrence of brake squeal.
That is, also in the case of this example, as in the case of the second example of the conventional structure described above, the portion between the outer peripheral surface of the rim portion 26a (26b) and the inner peripheral surface of the lining 27a (27b) is Although the damping member 28 is sandwiched, particularly in the case of this example, the installation position of the damping member 28 is selected in consideration of the vibration mode and satisfies both the first and second conditions described above. It is said.
Thus, in the case of this example, the damping member 28 is installed only in the portion corresponding to the abdomen where the displacement amount increases with respect to the vibration mode (vibration waveform) related to the predetermined squeal frequency. Compared to the second example, the installation area (installation range) of the attenuation member 28 can be reduced. Accordingly, since the amount of the attenuation member 28 used can be reduced, the manufacturing cost can be reduced. Specifically, when it is assumed that the brake shoes 16a and 16b of the present example and the brake shoe 5a of the second example of the conventional structure are the same size, the damping is smaller than that of the second example of the conventional structure. The amount of the member 28 used can be reduced by about 84%. In addition, since it is possible to easily remove the worn lining 27a (27b) from the outer peripheral surface of the rim portion 26a (26b), it is possible to improve the work efficiency of the lining replacement work. Further, in the case of this example, the portion corresponding to the abdomen where the amount of displacement is large, which is a portion where the brake squeal occurs, is specified and the attenuation member 28 is sandwiched, so that the amount of use of the attenuation member 28 is small. Nevertheless, the occurrence of brake squeal can be suppressed. Further, since the amount of use of the damping member 28 can be suppressed, it is possible to prevent the vibration eigenvalues of the brake shoes 16a and 16b from changing greatly. Therefore, according to the structure of this example, it is possible to effectively prevent the occurrence of a brake squeal having a frequency (unexpected frequency) different from the brake squeal which is a problem in the brake shoe without the damping member 28 interposed.

Next, squeal evaluation by simulation and eigenvalue change (FEM analysis) performed to confirm the effect of preventing the occurrence of brake squeal will be described.
[Sound evaluation by simulation]
The present inventors performed a simulation by a general complex eigenvalue analysis as an evaluation method of brake squeal and evaluated the vibration instability (dynamic instability) of the drum brake device. Specifically, the index instability (ease of occurrence of squealing at 2 kHz) indicating brake squealing is equivalent to the first example of the conventional structure, and the lining is fixed to the rim portion only with the rivet (Comparative Example 1). ), And a structure corresponding to the second example of the conventional structure, which is fixed with a rivet and a wide range (the same part as the oblique lattice part shown in FIG. 19) is adhered by a damping member (adhesive) (Comparative Example 2), Calculations were made for each of the structures (examples) of this example, and evaluation was performed based on the calculated values of Comparative Example 1. Table 1 shows the evaluation results.

  As is apparent from Table 1, according to the structure of the example, a result that the squeal of 2 kHz can be suppressed by 30% is obtained as compared with Comparative Example 1 which is a structure fixed only by rivets. It was confirmed that it is advantageous for preventing the occurrence of brake squeal. Moreover, according to the structure of the Example, the result that the suppression rate of the squeal of 2 kHz increased compared with the comparative example 2 which is the structure which adhere | attached the wide range was obtained. Such a result is that, in the case of the structure of Comparative Example 2, due to the wide application range of the damping member, the eigenvalue change becomes large and it is difficult to sufficiently suppress the 2 kHz vibration. It is thought to be the cause.

[Eigenvalue change (FEM analysis)]
As in the case of the squeal evaluation by the simulation described above, a structure corresponding to the first example of the conventional structure, in which the lining is fixed to the rim portion only by the rivet (Comparative Example 1), and a rivet corresponding to the second example of the conventional structure The eigenvalues are obtained by the finite element method (FEM analysis) and compared for the structure (Comparative Example 2) that is fixed with a damping member (adhesive) and bonded over a wide area (Comparative Example 2) and the structure of this example (Example). Evaluation was made based on the eigenvalue of Example 1. Table 2 shows the calculation result by such a finite element method.

  As is apparent from Table 2, according to the structure of the example, a result that the change of the eigenvalue when the comparative example 1 was used as a reference was suppressed as compared with the structure of the comparative example 2. Therefore, according to the structure of the example, it was confirmed that unexpected noises were less likely to occur compared to the structure of Comparative Example 2.

[Example]
Next, an experiment carried out to confirm the effect of preventing the occurrence of brake squeal will be described. As in the case of the squeal evaluation and the eigenvalue change (FEM analysis) described above, the inventors of the present invention correspond to the first example of the conventional structure, and the brake shoe with the lining fixed to the rim portion only by the rivet (comparative example) 1), a brake shoe (Comparative Example 2), which corresponds to the second example of the conventional structure, and is fixed with a rivet and bonded over a wide area by a damping member (adhesive), and the brake shoe (Example) of this example Two each were prepared. In addition, each brake shoe which concerns on these comparative examples 1 and 2 and an Example is completely the same except the presence or absence of an attenuation member, and the application range (adhesion range) of an attenuation member differing. In addition, the installation position (application position) of the damping member of the brake shoe according to the example is such that the acceleration pickup is attached between the rivets on the inner peripheral surface of the rim part constituting the brake shoe according to Comparative Example 1. The determination was made based on the measured vibration waveform (see FIG. 9). Then, a pair of brake shoes according to the comparative examples 1 and 2 and the example were incorporated into a drum brake device to obtain three samples.

  In the experiment, for each of the three samples, a backing plate is supported on a non-rotating portion, and a drum having a tire mounted around it is supported by a shaft member corresponding to an axle, and this shaft member is used as a dedicated dynamo device. It was driven to rotate. In addition, a noise meter (microphone) was installed at a position 30 cm away from each sample, and the sound generated during braking was measured. Then, braking is performed at a predetermined deceleration by a drum brake device as a sample from a state in which the shaft member is rotated at a predetermined rotation speed, and a sound of 2 kHz among sounds generated at the time of braking becomes 70 dB or more. The case where the brake squeal occurred was evaluated. As a result, when the brake shoe corresponding to Comparative Example 1 is used, the brake squeal occurrence rate is 24%, and when the brake shoe corresponding to Comparative Example 2 is used, the brake squeal occurrence rate is 22%. When the corresponding brake shoe was used, the occurrence rate of brake squeal became 0%. Also from this result, according to the drum brake device 1a of this example, it was confirmed that generation | occurrence | production of a brake squeal can be suppressed effectively.

[Second Example of Embodiment]
A second example of the embodiment of the present invention will be described with reference to FIG. Also in the case of this example, as in the case of the first example of the above-described embodiment, the damping member 28a is provided between the outer peripheral surface of the rim portion 26a (26b) (not shown) and the inner peripheral surfaces of the linings 27a and 27b. However, particularly in the case of this example, the installation position of the damping member 28a is only the circumferential center position (Xa) of the brake shoes 16c and 16d. In other words, the damping member 28a is not applied to the portions near the both ends in the circumferential direction (Xb, Xc, see FIG. 10) applied in the first example of the embodiment.

In the case of this example having the above-described configuration, the amount of the attenuation member 28a used can be reduced as compared with the case of the first example of the embodiment. For this reason, the manufacturing cost can be further reduced, and the work efficiency of the lining reworking operation can be further improved. Further, in the case of this example, the evaluation of squealing by the same simulation as in the case of the first example of the embodiment was performed. As a result, 16 squeezing of 2 kHz was obtained compared to Comparative Example 1 having a structure fixed only by rivets. % Was obtained, and it was confirmed that the structure of this example is advantageous in preventing the occurrence of brake squeal.
About another structure and an effect, it is the same as that of the case of the 1st example of embodiment mentioned above.

[Third example of embodiment]
A third example of the embodiment of the present invention will be described with reference to FIG. Also in the case of this example, similarly to the case of the first example of the above-described embodiment, the damping member 28b is provided between the outer peripheral surface of the rim portion 26a (26b) (not shown) and the inner peripheral surfaces of the linings 27a and 27b. However, particularly in the case of this example, the installation positions of the damping member 28b are set at two positions (Xd, Xe) in the circumferential direction of the brake shoes 16e, 16f. Further, in the case of this example, the circumferential dimension W _28b about the damping member 28b, in the first example of the embodiment, the damping member 28 in the circumferential direction width W ₂₈ (see FIG. 10) 1.5 times.

In the case of this example having the above-described configuration, the amount of use of the damping member 28b is the same as that in the first example of the embodiment, and compared with the case of the second example of the conventional structure. The amount used can be reduced sufficiently. Further, in the case of this example, the squeaking evaluation by the same simulation as in the case of the first example of the embodiment was performed. As a result, the squealing at 2 kHz was 7% compared to the comparative example 1 having a structure fixed only by rivets. % Was obtained, and it was confirmed that the structure of this example is advantageous in preventing the occurrence of brake squeal.
About another structure and an effect, it is the same as that of the case of the 1st example of embodiment mentioned above.

[Fourth Example of Embodiment]
A fourth example of the embodiment of the present invention will be described with reference to FIG. In the case of this example, of the pair of brake shoes 16g and 16h, one brake shoe 16g is the same as the brake shoe 16a used in the first example of the embodiment described above. Yes. However, for the other brake shoe 16h, the damping member 28 is provided between the outer peripheral surface of the rim portion 26b (not shown) and the inner peripheral surface of the lining 27b, as in the case of the first example of the conventional structure described above. Not pinched (adhered).

In the case of this example having the above-described configuration, the usage amount of the attenuation member 28 can be reduced as compared with the case of the first example of the embodiment. For this reason, the manufacturing cost can be further reduced. Further, with respect to the other brake shoe 16h, it is possible to increase the efficiency of the lining replacement work. Further, in the case of this example, the squeal evaluation by the same simulation as in the case of the first example of the embodiment was performed. As a result, the squeal at 2 kHz was compared with the comparative example 1 having a structure fixed only by the rivets. % Was obtained, and it was confirmed that the structure of this example is advantageous in preventing the occurrence of brake squeal. Such a result is the same even when the arrangement positions of the brake shoes 16g and 16h are changed.
About another structure and an effect, it is the same as that of the case of the 1st example of embodiment mentioned above.

  The present invention is not limited to a double-acting type two-leading type, but can be applied to drum brake devices having various structures such as a single-acting type two-leading type, a leading trailing type, and a duo servo type.

  Further, in each example of the embodiment, only the case where a damping member made of an adhesive is used has been described. However, when the present invention is carried out, the damping member other than the adhesive itself is used as the damping member. A simple plate material or layer material having no adhesiveness can be used. Further, when such a plate material or layer material is used, it can be attached to the outer peripheral surface of the rim portion, the inner peripheral surface of the lining, or both surfaces with a separately prepared adhesive material.

  Further, the application position of the attenuation member is not limited to the structure of each example of the embodiment. For example, even when the shape (application shape) of the damping member is a belt shape extending in the width direction of the brake shoe, the application positions (slanted lattice positions) as shown in FIGS. Can be adopted. In addition, when a damping member is installed only in a portion corresponding to the abdomen for a vibration waveform in which an abdominal part and a node part having a radial amplitude appear alternately in the width direction, the shape of the damping member (application shape) However, in this case, for example, application positions (slanted lattice positions) as shown in FIGS. 15A to 15D are adopted. it can. Further, as the application shape of the damping member, as shown in FIG. 16A, a width direction belt-like portion extending in the width direction of the drum brake shoe and a circumferential direction extending in the circumferential direction of the drum brake shoe. A cross shape in which the belt-like portions cross each other at a right angle at the center, an L-shape in which the end portions of the width-direction belt-like portion and the circumferential belt-like portion are continuous at right angles, as shown in (B), As shown in (C) and (D), the end of the width direction belt-shaped portion is connected to the middle portion of the circumferential band shape at a right angle (or the width of the end of the circumferential band shape is omitted although not shown). A T-shape or the like in which the middle part of the direction belt-like part is continuous at a right angle can be adopted. In short, an appropriate shape can be obtained in consideration of the vibration mode of the drum brake device.

  Further, in the above description, the case where the frequency of 2 kHz that is easily audible as an unpleasant noise is targeted, but when the present invention is implemented, the target squeal frequency is not limited to 2 kHz. It is possible to appropriately select from 0 to 16 kHz which is a general human audible range.

DESCRIPTION OF SYMBOLS 1, 1a Drum brake device 2, 2a Backing plate 3, 3a, 3b Wheel cylinder 4, 4a Piston 5, 5a Brake shoe 6 Web 7 Rim part 8 Lining 9 Anchor part 10, 10a Return spring 11, 11a Drum 12, 12a, 12b Rivet 13, 13a Rim portion side insertion hole 14 Lining side insertion hole 15 Damping member 16a-16h Brake shoe 17 Fitting insertion hole 18 Bolt hole 19 Adjuster mechanism 20 Adjuster gear 21 Adjuster screw 22 Gear stopper 23 Bolt 24 Shoe hold spring 25a, 25b Web 26a, 26b Rim part 27a, 27b Lining 28, 28a, 28b Damping member 29 Rim part side through hole 30 Lining side through hole

Claims (7)

A drum brake shoe, which is formed by fixing a lining to a circular arc plate-shaped rim portion provided on an outer peripheral edge of a web by using a plurality of fixing tools, and is used by being incorporated in a drum brake device,
Of the portion between the outer peripheral surface of the rim portion and the inner peripheral surface of the lining, the rim is attached to the rim by using only these fixing tools, and the portions that are removed from the portions through which the fixing tools are inserted. With respect to a vibration mode related to a predetermined squeal frequency for a drum brake device incorporating a drum brake shoe when fixed to a part, a damping member is clamped only at a part corresponding to at least one abdomen. Drum brake shoe.   The drum brake shoe according to claim 1, wherein the damping member is made of an adhesive, and the outer circumferential surface of the rim portion and the inner circumferential surface of the lining are bonded to each other by the damping member.   The drum brake shoe according to claim 1, wherein the damping member is a plate material or a film material that does not have adhesiveness.   The drum brake shoe according to any one of claims 1 to 3, wherein the damping member has a band shape extending in the width direction of the drum brake shoe.   The drum brake shoe according to any one of claims 1 to 3, wherein the damping member has a band shape extending in a circumferential direction of the drum brake shoe.   A widthwise belt-like portion provided in a state where the damping member extends in the width direction of the drum brake shoe and a circumferential belt-like portion provided in a state of extending in the circumferential direction of the drum brake shoe are mutually connected. The shoe for a drum brake according to any one of claims 1 to 3, wherein the shoe is configured in a right angle combination. A backing plate supported and fixed to the components of the suspension device;
A pair of shoes supported at two positions opposite to the radial direction of the backing plate so as to be capable of displacement in the radial direction of the backing plate;
A drum that covers both the shoes and rotates with the wheels;
In order to expand and contract the space between these shoes, an expansion / contraction device provided between the webs constituting these shoes,
In the provided drum brake device,
A drum brake device, wherein at least one of the two shoes is the drum brake shoe according to any one of claims 1 to 6.

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