JP7196743B2 - drum brake - Google Patents

Description

The present invention relates to drum brakes.

Conventionally, a drum brake as described in Patent Document 1 is known.
The above-mentioned drum brake consists of a brake drum as a drum body that rotates with the wheel, a pair of shoe webs arranged in mutually symmetrical positions inside the brake drum, and the inner peripheral surface of the brake drum between the pair of shoe webs. A pair of brake shoes having linings provided on opposing portions thereof. Further, the drum brake has a wheel cylinder as an expansion mechanism that pushes out a pair of shoe webs toward the inner peripheral surface of the brake drum to bring the linings of the pair of brake shoes into contact with the inner peripheral surface of the brake drum.

JP 2016-70335 A

By the way, in a drum brake, for example, contact between the linings of a pair of brake shoes and the brake drum may change the surface condition of the linings and increase the surface pressure acting on the drum body. As a result, the frictional force between the lining and the brake drum and the braking force of the vehicle become strong, and there is a risk that the vehicle will be braked suddenly.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems existing in the prior art, and it is an object of the present invention to provide a brake mechanism capable of adjusting the surface pressure acting on the drum body. .

A drum brake that solves the above problems comprises a cylindrical drum body that rotates with the wheel, a pair of arc-shaped shoe webs that are arranged at mutually symmetrical positions inside the drum body, and a pair of brake shoes having linings provided on portions facing the inner peripheral surface of the drum body; an expansion mechanism for bringing the lining into contact with the inner peripheral surface of the drum body, wherein one of the portions where both ends of the pair of shoe webs face each other is defined as a first facing portion, and the pair of shoe webs When the other of the portions where both ends of each of the two are opposed to each other is a second opposing portion, at least one of the pair of shoe webs is composed of a first divided shoe web provided near the first opposing portion, and the and a second split shoe web provided near the second opposing portion, and the first split shoe web and the second split shoe web possessed by one of the brake shoes are divided into the first split shoe web and the second shoe web section. The first split shoe web and the second split shoe web of the brake shoe maintain the first split shoe web and the second split shoe web close to and separated from each other around the support member. A split shoe distance adjustment mechanism is provided.

According to this, the split shoe distance adjusting mechanism can maintain the first split shoe web and the second split shoe web of one brake shoe in a state of approaching and separating. Therefore, for example, when the frictional force between the lining and the drum body, and thus the braking force, increases, the split shoe distance adjusting mechanism brings the first split shoe web and the second split shoe web closer to each other, so that the lining is removed from the drum body. The force pressed against the inner peripheral surface of the is weakened. Therefore, the surface pressure between the brake shoes and the drum body can be reduced. Further, for example, when the frictional force between the lining and the drum main body and, in turn, the braking force becomes weak, the split shoe distance adjusting mechanism separates the first split shoe web from the second split shoe web, so that the lining is removed from the drum main body. The force pressed against the inner peripheral surface of the is increased. Therefore, it is possible to increase the surface pressure between the brake shoes and the drum body. Therefore, the surface pressure acting on the drum body can be adjusted.

In the drum brake described above, the split shoe distance adjusting mechanism is a rod-like connection that is connected to each of the first split shoe web and the second split shoe web of one brake shoe, and has a male thread at its tip. and a connecting member for connecting the connecting members connected to the first shoe web segment and the second shoe web segment, wherein the first shoe web segment and the second shoe web segment are connected to each other. The connection member and the connection member, which are connected to each other, are provided coaxially, and the connection member is provided with an insertion hole through which the tip portion of the connection member is inserted. A female thread into which the male thread is screwed may be provided on the peripheral surface.

According to this, the connecting member connected to each of the first split shoe web and the second split shoe web of one brake shoe, and the connecting member connected to each of the first split shoe web and the second split shoe web. A connecting member that connects the connecting members is provided coaxially. The distal end portion of the connecting member and the insertion hole of the connecting member are screwed together by a configuration of male and female threads. Therefore, by rotating the connecting member in a predetermined direction around the axis of the connecting member, the distal end portion of the connecting member moves in a direction in which it is inserted into or removed from the insertion hole of the connecting member. For example, when the distal end portion of the connecting member moves in the direction in which it is inserted into the insertion hole of the connecting member, the first shoe web segment and the second shoe web segment approach the connecting member by the connecting member. Therefore, the first split shoe web and the second split shoe web can be brought close to each other. Further, when the distal end portion of the connecting member moves in the direction in which it is removed from the insertion hole of the connecting member, the first split shoe web and the second split shoe web are separated from the connecting member by the connecting member. Therefore, the first split shoe web and the second split shoe web can be separated. Since the distal end portion of the connecting member and the insertion hole of the connecting member have a structure in which the male and female threads are screwed together, the first split shoe web and the second split shoe web are brought closer to each other and separated from each other. can be maintained in good condition. Therefore, the first split shoe web and the second split shoe web can be brought closer to each other and separated from each other by a simple screw engagement configuration.

In the drum brake described above, the support member may be an elastic member having elasticity.
For example, in a state where the first split shoe web and the second split shoe web are maintained in the state of approaching and separating from each other by the split shoe distance adjustment mechanism, if an external force acts on the drum brake, the first split shoe web and the second split shoe web will move. The split shoe webs may not be able to maintain closeness and separation.

In this respect, according to this, even if an external force acting on the drum brake is transmitted to the first split shoe web and the second split shoe web, the external force can be absorbed by the support member made of the elastic member. Therefore, it is possible to easily maintain the state in which the first split shoe web and the second split shoe web are close to each other and separated from each other.

According to this invention, the surface pressure acting on the drum body can be adjusted.

Schematic of a drum brake. Schematic which shows the surface pressure of a drum brake. FIG. 4 is a cross-sectional view of the split shoe distance adjusting mechanism; FIG. 4 is a schematic diagram showing the operation of the split shoe distance adjusting mechanism; FIG. 5 is a cross-sectional view of a split shoe distance adjusting mechanism in a modified example;

An embodiment embodying a drum brake will be described below with reference to FIGS. 1 to 4. FIG.
As shown in FIG. 1, the drum brake 10 is a device that generates braking force (braking force) for a vehicle. The drum brake 10 includes a cylindrical drum body 20 , a pair of brake shoes 30 and an extension mechanism 40 . The drum body 20 rotates together with the wheels by being fixed to the axle. The pair of brake shoes 30 is composed of a pair of plate-like shoe webs 31 arranged at mutually symmetrical positions inside the drum main body 20, and a position where the pair of shoe webs 31 face the inner peripheral surface 20a of the drum main body 20. and an arcuate lining 32 provided on the . The expansion mechanism 40 is a wheel cylinder that pushes out the pair of shoe webs 31 toward the inner peripheral surface 20 a of the drum body 20 to bring the linings 32 of the pair of brake shoes 30 into contact with the inner peripheral surface 20 a of the drum body 20 . The wheel cylinder has a hydraulic mechanism 41 and a pair of rod portions 42 connected to the pair of shoe webs 31 respectively. The wheel cylinder is configured such that when the brake pedal of the vehicle is stepped on, the pair of rod portions 42 are extended toward the inner peripheral surface 20a of the drum body 20 by hydraulic fluid sent to the hydraulic mechanism 41 of the wheel cylinder. It is Note that a gap is formed between the linings 32 of the pair of brake shoes 30 and the inner peripheral surface 20a of the drum body 20 when the vehicle does not generate a braking force. In order to form the gap, a return spring (not shown) constantly generates a restoring force to separate the pair of brake shoes 30 from the inner peripheral surface 20 a of the drum body 20 .

One of the portions where both ends of the pair of shoe webs 31 face each other is defined as a first facing portion A, and the other of the portions where both ends of the pair of shoe webs 31 face each other is defined as a second facing portion B. and In the present embodiment, the first facing portion A is a portion located closer to the expansion mechanism 40 among the portions where the pair of shoe webs 31 face each other. The pair of shoe webs 31 are divided into a first split shoe web 31a provided near the first facing portion A and a second split shoe web 31b provided near the second facing portion B. As shown in FIG.

The first split shoe web 31a and the second split shoe web 31b of one brake shoe 30 are connected by a support member 45 provided at the boundary portion Tb. The support member 45 is an elastic member having elasticity. The support member 45 is specifically made of resin such as urethane rubber. Therefore, the first split shoe web 31a and the second split shoe web 31b of one brake shoe 30 are arranged so that the first split shoe web 31a and the second split shoe web 31b can approach and separate from each other around the boundary portion Tb. It is supported by the support member 45 .

Also, at the first facing portion A, the ends of the first split shoe webs 31a of the pair of brake shoes 30 face each other. Ends of the first split shoe webs 31 a of the pair of brake shoes 30 are connected to each other by anchor pins 80 . At the second opposing portion B, the ends of the second split shoe webs 31b of the pair of brake shoes 30 are opposed to each other. Each end of the second split shoe web 31b of the pair of brake shoes 30 is in contact with the anchor block 81. As shown in FIG.

Next, operation of the drum brake 10 will be described with reference to FIG. For convenience of explanation, FIG. 2 shows the magnitude of the surface pressure acting on the inner peripheral surface 20a of the drum body 20. As shown in FIG. The magnitude of the surface pressure varies depending on the amount of extension of the pair of rod portions 42 of the expansion mechanism 40, but the magnitude of the surface pressure shown in FIG. A state in which a sufficient surface pressure is applied to the surface 20a is described as an example.

As shown in FIG. 2, the extension mechanism 40 is activated when the brake pedal of the vehicle is depressed. A pair of rod portions 42 of the extension mechanism 40 push out the pair of shoe webs 31 toward the inner peripheral surface 20 a of the drum body 20 . At this time, the pair of rod portions 42 of the expansion mechanism 40 push out the pair of shoe webs 31 toward the inner peripheral surface 20a of the drum body 20 so as to resist the restoring force of the return spring (not shown). The pair of brake shoes 30 are pushed apart so as to rotate toward the inner peripheral surface 20a of the drum body 20 about the anchor pin 80 connecting the first split shoe webs 31a. The ends of the second split shoe webs 31 b of the pair of brake shoes 30 are separated from the anchor block 81 . When the linings 32 of the pair of brake shoes 30 come into contact with the inner peripheral surface 20a of the drum body 20, surface pressure (shaded area in FIG. 2) acts on the inner peripheral surface 20a of the drum body 20. As shown in FIG. Since the drum body 20 rotates together with the wheels, a frictional force acts between the drum body 20 and the inner peripheral surface 20a. The frictional force becomes the braking force (braking force) of the vehicle.

Here, in the drum brake 10, for example, due to contact between the linings 32 of the pair of brake shoes 30 and the drum body 20, the surface condition of the linings 32 may change, and the surface pressure may increase (the white line in FIG. 2). blank area). As a result, the frictional force between the lining 32 and the drum body 20 and the braking force of the vehicle become strong, and there is a risk that the vehicle will be braked suddenly. In view of the above problem, the present embodiment employs a split shoe distance adjusting mechanism 50 as a structure capable of adjusting the surface pressure between the brake shoe and the drum body. In this embodiment, it is assumed that the surface pressure applied to the inner peripheral surface 20a of the drum body 20 by both the linings 32 of the pair of brake shoes 30 is increased.

A split shoe distance adjusting mechanism 50 is provided for each of the pair of brake shoes 30 . The split shoe distance adjusting mechanism 50 includes a rod-like connecting member 51 connected to each of the first split shoe web 31a and the second split shoe web 31b of one brake shoe 30, and the first split shoe web 31a and the second split shoe web 31b. A connecting member 52 for connecting connecting members 51 connected to each of the split shoe webs 31b. The connection member 51 has a fixing portion 51a connected to the first split shoe web 31a and the second split shoe web 31b. The fixing portion 51a is, for example, a hook-shaped hook portion that is fitted into a fixing hole provided so as to pass through the first split shoe web 31a and the second split shoe web 31b in the plate thickness direction.

As shown in FIG. 3, the connecting member 51 and the connecting member 52 of the split shoe distance adjusting mechanism 50 are provided coaxially. A distal end portion 51b of the connecting member 51 is provided with a male screw 51c. The connecting member 52 has a cylindrical shape. The connecting member 52 is provided with an insertion hole 52a through which the distal end portion 51b of the connecting member 51 is inserted. Female threads 52b are provided on the inner peripheral surfaces of both ends of the connecting member 52 in the insertion hole 52a. That is, the male thread 51c of the tip portion 51b of the connecting member 51 and the female thread 52b of the insertion hole 52a of the connecting member 52 are screwed together. Further, in the present embodiment, the length of the range in which the male screw 51c is provided at the distal end portion 51b of the connecting member 51 in the direction in which the axes of the connecting member 51 and the connecting member 52 extend is It is the same as the length of the range where the internal thread 52b is provided. A portion of the distal end portion 51b of the connecting member 51 is maintained in a state in which it is inserted through the insertion hole 52a of the connecting member 52 . Therefore, in the split shoe distance adjusting mechanism 50, by rotating the connecting member 52 about the axis of the connecting member 51 in a predetermined direction, the distal end portion 51b of the connecting member 51 enters or passes through the insertion hole 52a of the connecting member 52. removed.

As shown in FIG. 4, the split shoe distance adjusting mechanism 50 causes the first split shoe web 31a and the second split shoe web 31b to approach and separate from each other around the support member 45 according to the rotation direction of the connecting member 52. keep in condition. In the present embodiment, as explained with reference to FIG. The connecting member 52 is rotated in the direction in which it is inserted into the insertion hole 52a. By doing so, the first split shoe web 31a and the second split shoe web 31b are maintained close to each other with the support member 45 as the center. By bringing the first shoe web segment 31a and the second shoe web segment 31b closer together, the state before the first shoe web segment 31a and the second shoe web segment 31b are brought closer (two points in FIG. 4). 4), the position of the lining 32 moves away from the inner peripheral surface 20a of the drum body 20 (shown by the solid line in FIG. 4).

Further, the timing of moving the first split shoe web 31a and the second split shoe web 31b toward and away from each other by rotating the connecting member 52 of the split shoe distance adjusting mechanism 50 depends on the situation before the vehicle runs, that is, the drum This is the timing when the main body 20 is not rotating. The frequency of approaching and separating the first split shoe web 31a and the second split shoe web 31b by the split shoe distance adjusting mechanism 50 is appropriately determined according to the surface condition of the lining 32 of the drum brake 10 and the braking force generation condition of the vehicle. You can change it. The state in which a part of the distal end portion 51b of the connecting member 51 is inserted through the insertion hole 52a of the connecting member 52 described with reference to FIG. and the state before separating.

The following actions and effects can be obtained in this embodiment.
(1) In the present embodiment, the split shoe distance adjusting mechanism 50 can maintain the first split shoe web 31a and the second split shoe web 31b of one brake shoe 30 in a state of approaching and separating. Therefore, for example, when the frictional force between the lining 32 and the drum main body 20, and thus the braking force, increases, the split shoe distance adjusting mechanism 50 brings the first split shoe web 31a and the second split shoe web 31b closer to each other. , the force with which the lining 32 is pressed against the inner peripheral surface 20a of the drum body 20 is weakened. Therefore, the surface pressure between the brake shoes 30 and the drum body 20 can be reduced. Further, for example, when the frictional force between the lining 32 and the drum body 20, and thus the braking force, becomes weak, the split shoe distance adjusting mechanism 50 separates the first split shoe web 31a from the second split shoe web 31b. , the force with which the lining 32 is pressed against the inner peripheral surface 20a of the drum body 20 increases. Therefore, the surface pressure between the brake shoes 30 and the drum body 20 can be increased. Therefore, the surface pressure acting on the drum body 20 can be adjusted.

(2) In the present embodiment, the connection member 51 connected to each of the first split shoe web 31a and the second split shoe web 31b of one brake shoe 30, the first split shoe web 31a and the second split shoe web A connecting member 52 that connects the connecting members 51 connected to each of the shoe webs 31b is provided coaxially. The distal end portion 51b of the connecting member 51 and the insertion hole 52a of the connecting member 52 are screwed together by the configuration of the male thread 51c and the female thread 52b. Therefore, by rotating the connecting member 52 about the axis of the connecting member 51 in a predetermined direction, the distal end portion 51b of the connecting member 51 moves in a direction of being inserted into or removed from the insertion hole 52a of the connecting member 52 . For example, when the distal end portion 51 b of the connecting member 51 moves in the direction of insertion into the insertion hole 52 a of the connecting member 52 , the first split shoe web 31 a and the second split shoe web 31 b are moved by the connecting member 51 to the connecting member 52 . approach towards. Therefore, the first split shoe web 31a and the second split shoe web 31b can be brought close to each other. Further, when the distal end portion 51b of the connecting member 51 moves in the direction of being pulled out from the insertion hole 52a of the connecting member 52, the first split shoe web 31a and the second split shoe web 31b are moved by the connecting member 51 to the connecting member 52. move away from Therefore, the first split shoe web 31a and the second split shoe web 31b can be separated from each other. Since the distal end portion 51b of the connecting member 51 and the insertion hole 52a of the connecting member 52 have a structure in which the male thread 51c and the female thread 52b are screwed together, the first split shoe web 31a and the second split shoe web 31a are separated from each other. The web 31b can be maintained in close proximity and spaced apart. Therefore, the first split shoe web 31a and the second split shoe web 31b can be brought closer to each other and separated from each other by a simple screw engagement configuration.

(3) For example, when the first split shoe web 31a and the second split shoe web 31b are maintained in the state of approaching and separating from each other by the split shoe distance adjusting mechanism 50, when an external force acts on the drum brake 10, the second There is a possibility that the first split shoe web 31a and the second split shoe web 31b cannot be maintained in the close and separated state.

In this regard, in this embodiment, even if the external force acting on the drum brake 10 is transmitted to the first split shoe web 31a and the second split shoe web 31b, the external force can be absorbed by the support member 45 made of an elastic member. . Therefore, it is possible to easily maintain the state in which the first split shoe web 31a and the second split shoe web 31b are close to each other and separated from each other.

(4) In this embodiment, the surface pressure between the brake shoe 30 and the drum body 20 can be adjusted as described in (1). Therefore, for example, when the surface pressure acting on the inner peripheral surface 20a of the drum body 20 increases, the braking force of the vehicle suddenly increases, or when the brake noise occurs when the braking force is generated. Also in , the surface pressure between the brake shoe 30 and the drum body 20 can be suppressed by the split shoe distance adjusting mechanism 50 . Therefore, it is possible to suppress a sudden increase in braking force and brake squeal during braking of the vehicle.

In addition, this embodiment can be changed and implemented as follows. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
The support member 45 is an elastic member, but for example, the first split shoe web 31a and the second split shoe web 31b may be connected by a pin or the like. In this case, the pin supports the first split shoe web 31a and the second split shoe web 31b so that the first split shoe web 31a and the second split shoe web 31b can approach and separate from each other.

○ In the split shoe distance adjusting mechanism 50, the length of the range where the male thread 51c is provided at the tip 51b of the connecting member 51 is the same as the length of the range where the female thread 52b is provided in the insertion hole 52a of the connecting member 52. However, it is not limited to this. For example, the length of the range where the male thread 51c is provided in the distal end portion 51b of the connecting member 51 may be shorter than the length of the range where the female thread 52b is provided in the insertion hole 52a of the connecting member 52, or You can make it longer. Assuming the state before the first split shoe web 31a and the second split shoe web 31b are moved toward and away from each other, the tip portion 51b of the connecting member 51 is partially inserted into the insertion hole 52a of the connecting member 52. It can be changed in any way as long as it is maintained.

The divided shoe distance adjusting mechanism 50 is configured by the connecting member 51 and the connecting member 52, but it is not limited to this. For example, you may change as follows.
As shown in FIG. 5, the split shoe distance adjusting mechanism 50 includes a cylindrical first adjusting member 61, a cylindrical second adjusting member 62 fitted inside the first adjusting member 61, and a first adjusting member 61. It may be modified to include a positioning pin 63 that holds the positional relationship between the member 61 and the second adjusting member 62 . The second adjusting member 62 is provided so as to be insertable and removable with respect to the first adjusting member 61 . A first insertion hole 61a is provided at the distal end of the first adjustment member 61 to allow communication between the inside and the outside of the first adjustment member 61 . The second adjustment member 62 is provided with a plurality of second insertion holes 62a that communicate the inside and the outside of the second adjustment member 62 . The plurality of second insertion holes 62a are arranged so as to communicate with the first insertion holes 61a when the second adjustment member 62 is inserted into and extracted from the inside of the first adjustment member 61. As shown in FIG. The ends of the first adjusting member 61 and the second adjusting member 62 (not shown) are fixed to either the first split shoe web 31a or the second split shoe web 31b. In the split shoe distance adjusting mechanism 50 configured as described above, the first split shoe web 31a and the second split shoe web 31b are brought closer to each other and separated from each other by inserting and removing the second adjusting member 62 into and out of the first adjusting member 61. . Then, when a predetermined second insertion hole 62a among the plurality of second insertion holes 62a overlaps with the first insertion hole 61a, the positioning pin 63 is inserted through the first insertion hole 61a and the predetermined second insertion hole 62a. Thus, the positions of the first adjusting member 61 and the second adjusting member 62 are maintained. Therefore, the first split shoe web 31a and the second split shoe web 31b can be maintained in a state of being close to each other and separated from each other. Even with such a change, it is possible to obtain the same actions and effects as in the present embodiment.

Also, the split shoe distance adjusting mechanism 50 has a configuration in which the first split shoe web 31a and the second split shoe web 31b of one brake shoe 30 are connected by a wire, and an adjusting section for adjusting the length of the wire is provided. You can change it. The adjuster has a structure capable of winding a wire, for example. With such a change, a wire is used instead of the connection member 51, so that the weight of the divided shoe distance adjusting mechanism 50 and thus the weight of the drum brake 10 can be reduced.

In the present embodiment, both of the pair of shoe webs 31 are split into the first split shoe web 31a and the second split shoe web 31b, but this is not the only option. For example, only one of the pair of shoe webs 31 may be divided into the first divided shoe web 31a and the second divided shoe web 31b. Then, the first split shoe web 31a and the second split shoe web 31b are preferably connected by the split shoe distance adjusting mechanism in the present embodiment and the modified example described above.

In the present embodiment, the anchor block 81 is used in the second opposing portion B, but for example, a generally known adjusting mechanism for adjusting the distance between the pair of shoe webs 31 may be used. good. When the distance between the pair of shoe webs 31 is adjusted by the adjustment mechanism of this modification, the linings 32 of the pair of brake shoes 30 can be brought closer to and away from the inner peripheral surface 20a of the drum body 20, thereby The contact pressure between the shoe 30 and the drum body 20 can be adjusted. However, it is conceivable that the frequency of forward and backward movement of the vehicle differs depending on the usage conditions of the vehicle, and that the surface properties of only one of the linings 32 of the pair of brake shoes 30 may change. That is, in the adjusting mechanism of this modified example, there is a possibility that even the lining 32 that does not need to be adjusted is unintentionally moved toward or away from the inner peripheral surface 20a of the drum body 20 . In this regard, in the present embodiment, even if the distance between the pair of brake shoes 30 is adjusted using the adjusting mechanism of this modified example, either one of the split shoe distance adjusting mechanisms 50 can be further adjusted. By using the adjusting mechanism of this modified example together with the split shoe distance adjusting mechanism 50, it is possible to more finely adjust the proximity and separation between the first split shoe web 31a and the second split shoe web 31b.

◯ In this embodiment, the ends of the first split shoe web 31a are connected by the anchor pin 80, but this may be omitted. In this case, it is preferable that the expansion mechanism 40 has a function of connecting the ends of the first split shoe web 31a.

o Although the expansion mechanism 40 was a wheel cylinder, it may be changed to, for example, a generally known cam mechanism.
o The drum brake 10 of this embodiment can be changed to any drum brake. For example, there are a leading trading drum brake, a duo servo drum brake, a dual two leading drum brake, and the like.

DESCRIPTION OF SYMBOLS 10... Drum brake 20... Drum main body 20a... Inner peripheral surface of drum main body 30... Brake shoe 31... Shoe web 31a... First split shoe web 31b... Second split shoe web 32... Lining 40 Extending mechanism 45 Supporting member 50 Split shoe distance adjusting mechanism 51 Connecting member 51b Tip of connecting member 51c Male screw 52 Connecting member 52a Insertion hole 52b Female screw A First facing portion, B: Second facing portion, Tb: Boundary portion.

Claims (3)

a cylindrical drum body that rotates with the wheel;
A pair of arc-shaped shoe webs arranged at mutually symmetrical positions inside the drum body, and a pair of linings provided at portions of the pair of shoe webs facing the inner peripheral surface of the drum body. brake shoes of
an expansion mechanism that pushes the pair of shoe webs toward the inner peripheral surface of the drum body to bring the linings of the pair of brake shoes into contact with the inner peripheral surface of the drum body;
One of the portions where both ends of the pair of shoe webs face each other is defined as a first facing portion, and the other of the portions where both ends of each of the pair of shoe webs face each other is defined as a second facing portion. , at least one of the pair of shoe webs is divided into a first divided shoe web provided near the first facing portion and a second divided shoe web provided near the second facing portion. cage,
The first split shoe web and the second split shoe web of one brake shoe are separated from the first split shoe web and the second split shoe web around the boundary between the first split shoe web and the second split shoe web. Connected by a support member provided at the boundary portion so as to be able to approach and separate from the second split shoe web,
The first split shoe web and the second split shoe web of one brake shoe are in a state in which the first split shoe web and the second split shoe web are moved toward and away from each other around the support member. A split shoe distance adjustment mechanism is provided to maintain the
The split shoe distance adjustment mechanism includes:
a rod-shaped connection member connected to each of the first split shoe web and the second split shoe web of one brake shoe and having a male thread at its tip end;
a connecting member that connects the connecting members that are connected to the first split shoe web and the second split shoe web, respectively;
the connection member connected to each of the first split shoe web and the second split shoe web and the connecting member are provided coaxially,
The connecting member is provided with an insertion hole through which the tip portion of the connecting member is inserted,
A drum brake , wherein a female thread into which the male thread is screwed is provided on an inner peripheral surface of the insertion hole . a cylindrical drum body that rotates with the wheel;
A pair of arc-shaped shoe webs arranged at mutually symmetrical positions inside the drum body, and a pair of linings provided at portions of the pair of shoe webs facing the inner peripheral surface of the drum body. brake shoes of
an expansion mechanism that pushes the pair of shoe webs toward the inner peripheral surface of the drum body to bring the linings of the pair of brake shoes into contact with the inner peripheral surface of the drum body;
One of the portions where both ends of the pair of shoe webs face each other is defined as a first facing portion, and the other of the portions where both ends of each of the pair of shoe webs face each other is defined as a second facing portion. , at least one of the pair of shoe webs is divided into a first divided shoe web provided near the first facing portion and a second divided shoe web provided near the second facing portion. cage,
The first split shoe web and the second split shoe web of one brake shoe are separated from the first split shoe web and the second split shoe web around the boundary between the first split shoe web and the second split shoe web. Connected by a support member provided at the boundary portion so as to be able to approach and separate from the second split shoe web,
The first split shoe web and the second split shoe web of one brake shoe are in a state in which the first split shoe web and the second split shoe web are moved toward and away from each other around the support member. A split shoe distance adjustment mechanism is provided to maintain the
A drum brake , wherein the support member is an elastic member having elasticity . a cylindrical drum body that rotates with the wheel;
A pair of arc-shaped shoe webs arranged at mutually symmetrical positions inside the drum body, and a pair of linings provided at portions of the pair of shoe webs facing the inner peripheral surface of the drum body. brake shoes of
an expansion mechanism that pushes the pair of shoe webs toward the inner peripheral surface of the drum body to bring the linings of the pair of brake shoes into contact with the inner peripheral surface of the drum body;
One of the portions where both ends of the pair of shoe webs face each other is defined as a first facing portion, and the other of the portions where both ends of each of the pair of shoe webs face each other is defined as a second facing portion. , at least one of the pair of shoe webs is divided into a first divided shoe web provided near the first facing portion and a second divided shoe web provided near the second facing portion. cage,
The first split shoe web and the second split shoe web of one brake shoe are separated from the first split shoe web and the second split shoe web around the boundary between the first split shoe web and the second split shoe web. Connected by a support member provided at the boundary portion so as to be able to approach and separate from the second split shoe web,
The first split shoe web and the second split shoe web of one brake shoe are in a state in which the first split shoe web and the second split shoe web are moved toward and away from each other around the support member. A split shoe distance adjustment mechanism is provided to maintain the
The split shoe distance adjustment mechanism includes:
a tubular first adjustment member;
a cylindrical second adjustment member fitted inside the first adjustment member;
a locating pin, and
The first adjustment member is provided with a first insertion hole,
The second adjustment member is provided with a plurality of second insertion holes,
The first adjustment member is fixed to either one of the first split shoe web and the second split shoe web, and the second adjustment member is fixed to either the first split shoe web or the second split shoe web. fixed to the other,
The positional relationship between the first adjustment member and the second adjustment member is achieved by inserting the positioning pin in a state in which a predetermined second insertion hole out of all the second insertion holes overlaps the first insertion hole. A drum brake characterized by holding

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