JPH0539218Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to a brake band.

[Prior art] Generally, in brake bands, in order to stabilize the friction coefficient of the strap and prevent chattering, etc., the strap adapts to the outer peripheral surface of the brake drum to reduce drag torque (frictional resistance) between the two. is one of the important requirements.

To meet such requirements, a thin film with a relatively low degree of elasticity and a high degree of flexibility is used to provide longitudinally and laterally flexible sections as shown in Figure 3. The strap 50 and the sheet metal backing strips 51, 52 having relatively less flexibility and greater elasticity than the strap 50 are integrally provided, so that the strap 50 in the free state can form a horizontally long C as shown in the figure. A structure that bends in the shape of a letter (extending vertically in Figure 3) has already been proposed (Japanese Patent Publication No. 47-36555).

However, with that structure, when the strap 50 transitions from brake disconnection to brake connection,
As shown in the figure, the longitudinal intermediate portion 53 lifts up from the drum 54, and as shown in FIG.
It may reach more than 0.36Kgm.

In view of the above-mentioned problems, the present invention has been developed to
It is an object of the present invention to solve the above-mentioned problems by providing a brake band equipped with a strap that is shaped to embrace a brake drum all around the circumference from a state in which the longitudinal intermediate portion and both end portions are in contact with each other.

[Means for Solving the Problems] In order to solve the above problems, the invention according to claim 1 of the present invention provides a brake band having a strap disposed on the outer peripheral surface of a brake drum, in which the strap prevents the brake from being applied when the brake is turned off. When transitioning to connection, the arc of the intermediate portion in the brake disconnected state when the drum is set is set to be larger than the diameter of the brake drum so that the longitudinal intermediate portion and both ends embrace the entire circumference from the state in which they are in contact. The diameter of the brake drum is set to be larger than the diameter of the brake drum, and the arc of the connecting portion between the intermediate portion and the both end portions extending approximately perpendicular to the intermediate portion is set to be smaller than the diameter of the brake drum, and one point near both ends of the connecting portion is set. The brake drum is characterized in that the arc of the brake drum is set to be approximately equal to the diameter of the brake drum.

Furthermore, the invention according to claim 2 provides a brake band having a strap arranged on the outer circumferential surface of the brake drum, in which when the strap transitions from the time of brake disconnection to the time of brake connection, the longitudinal middle portion and both ends of the strap are The arc of the intermediate portion in the free state is set to be larger than the diameter of the brake drum so as to embrace the brake drum over the entire circumference from the contact state, and the intermediate portion extends in a direction generally perpendicular to the intermediate portion. The brake drum is characterized in that the arc of the connecting portion with both ends is approximately equal to the diameter of the brake drum.

[Operation] When the brake is applied from the brake-off state, the longitudinal middle part and both ends are in contact and gradually bend along the outer peripheral surface of the brake drum, hugging the brake drum over its entire circumference and braking its rotation. do.

[Example] In the following description, corresponding members are denoted by the same reference numerals, and the description will be omitted.

(First Embodiment) Fig. 1 shows a state in which the brake band 10 of the present invention is attached to a brake drum 11 (only the center is shown), and shows an example in which a band with a diameter D of 166 mm is adopted, for example. .

Reference numeral 12 in FIG. 1 denotes a strap formed into a generally annular shape, and is made of a highly elastic material such as carbon tool steel (for example, SK5 according to JIS standards) used for band saws, springs, forging dies, etc. When the strap 12 is made of such a highly elastic material, the strap 12 will not be deformed even when subjected to vibrations of the brake drum 11, and its durability can be improved accordingly. To manufacture the strap 12, first, a band-shaped metal plate is formed into a generally annular shape using rolls, then heat treated, and then a friction material 13 is attached to the inner peripheral surface. A slight notch 14 in the circumferential direction is provided between both ends 24 and 25 of the strap 12 formed at this time.

Here, in the present invention, the positive direction is 180 degrees clockwise from the circumferential center of the notch 14 around the arc center C of the strap 12 (the center of the brake drum 11), and the counterclockwise direction is 180 degrees clockwise from the circumferential center of the notch 14. If the angle is set in the negative direction, the arc in the range of 170 degrees to 180 degrees when the brake band 10 is set on the drum (when the drum is set), that is, the arc of the intermediate portion 15, as shown in the figure. brake drum 1
The diameter D of the brake drum 11 is larger than the diameter D of the brake drum 11. An arc of one point within the range of approximately 55 degrees to 70 degrees, that is, an arc of one point within the portions 18 and 19 near one end, and an arc of one point within the range of approximately 110 degrees to 125 degrees. In other words, the arc at one point in the portions 20 and 21 near the other end is set to be approximately equal to the diameter D of the brake drum 11.

The friction material 13 is uniformly attached to the inner peripheral surface of the strap 12, and is formed by, for example, double impregnation with resin. 22 and 23 are a pair of connector parts,
Both ends 24, 2 of the outer peripheral surface of the strap 12, respectively.
5 by welding or caulking. Each commentator part 22, 23 is, for example, JIS
It is formed from carbon steel for machine structural use such as S50C in the standard, and its middle portion is bent so as to protrude outward in the radial direction to form the bracket portions of the piston 26 and anchor pin 27, respectively.

According to the above structure, when the brake band 10 is in the brake cut-off state while driving the vehicle,
The brake drum 11 rotates, for example, in the forward direction.
At this time, the strap 12 is held at both ends 2 by the reaction force.
4 and 25 open in directions that repel each other.

Since the anchor pin 27 is always in contact with the bracket part of the connector part 23, when the piston 26 is protruded via a braking mechanism (not shown) and the bracket part of the connector part 22 is pressed in the direction of arrow A, both connectors The parts 22 and 23 are pressed in directions facing each other. In the first embodiment, the arc of the intermediate portion 15 is
The connecting portion 16,
The arc of the strap 17 is set smaller than the diameter D of the brake drum 11, and the arc of one point in the parts 18 to 21 near both ends is set almost equal to the diameter D of the brake drum 11.
5 and both end portions 24 and 25 are in contact with each other, they gradually bend along the outer peripheral surface of the brake drum 11, embrace the brake drum 11 over the entire circumference, and brake its rotation. At this time, as shown in Fig. 4B, the drag torque of the brake band 10 of the present invention is significantly reduced compared to the conventional structure A, and only about 0.04 kgm of torque is generated even in the range of 500 to 1500 rpm, which is the maximum value. . Therefore, the coefficient of friction is stabilized,
Since chattering etc. can be prevented, durability can be improved and fuel efficiency can be achieved.

(Second Example) The example shown in FIG. 2 shows a case where the shape of the brake band 10 in a free state, which is not attached to a brake drum, is specified.

As shown in the figure, the strap 12 in its free state is formed into a vertically long C-shape. The inner diameter a of the strap 12 in the long axis direction is approximately 155% to 165% of the diameter D of the corresponding drum (not shown), and the inner diameter b in the short axis direction is approximately 60% to 70% of the inner diameter a.
It is set to %. Then, when the strap 12 is divided parallel to the inner diameter b, the arc in the range of 45% to 55% of the center part of the inner diameter a, that is, the arc of the intermediate part 30, is set to 90% or more of the diameter D of the brake drum, and the inner diameter The arc in the range of 7.5% to 12.5% at both ends of a, that is, the arc of the connecting portions 31 and 32 extending in a direction perpendicular to the intermediate portion 30 is set to be 50% to 60% of the diameter D of the brake drum. .

Even when the brake band 10 having the shape shown in FIG. 2 is adopted, the strap 12 gradually bends along the outer peripheral surface of the brake drum 11 from the state where the intermediate portion 30 and both end portions 24 and 25 are in contact with each other, and the strap 12 bends over the entire circumference. Since the brake drum 11 is held and its rotation is braked, the characteristics shown in FIG. 4B can be obtained. Therefore, in the embodiment shown in FIG. 2 as well, durability is improved and fuel efficiency can be achieved.

[Effects of the invention] As explained above, according to the invention, when the brake is applied, the longitudinal middle part and both ends of the brake drum gradually bend along the outer circumferential surface of the brake drum from a state where they are in contact with each other, and the brake drum is bent over the entire circumference. Embrace it and brake its rotation. Therefore, the coefficient of friction is stabilized,
Since chattering etc. can be prevented, durability can be improved and fuel efficiency can be achieved.

Moreover, since the present invention can be easily implemented by simply specifying the shape of the strap in the free state or in the brake-off state when the drum is set, there is little increase in cost despite the significant quality improvement.

[Brief explanation of drawings]

Figure 1 is a diagram of the installed state of the brake band of the present invention seen in a cross section of the brake drum, Figure 2 is a diagram of the free state of the brake band of the present invention, and Figure 3 is a diagram of the conventional brake band seen in the cross section of the brake drum. FIG. 4, which is a diagram showing the state of attachment of the brake band, is a graph showing measured values of drag torque. 10...brake band, 11...brake drum, 12...strap, 15...middle part, 1
6, 17... Connection portion, 18-21... Both ends vicinity portion, 30... Intermediate portion, 31, 32... Connection portion.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a brake band equipped with a strap disposed on the outer peripheral surface of the brake drum, when the strap transitions from brake disconnection to brake connection, In order to hug the brake drum all the way from the contact state, the arc of the intermediate part in the brake disconnected state when the drum is set is set to be larger than the diameter of the brake drum, and The arc of the connecting portion between the two end portions extending approximately at right angles is set to be smaller than the diameter of the brake drum, and the arc of one point near both ends of the connecting portion is set to be approximately equal to the diameter of the brake drum. A brake band featuring (2) In a brake band equipped with a strap placed on the outer circumferential surface of the brake drum, when the strap transitions from brake disconnection to brake connection, the strap touches the entire circumference from the state in which the longitudinal middle and both ends contact each other. A circular arc of the intermediate portion in a free state is set to be larger than a diameter of the brake drum so as to embrace the brake drum, and a connection portion between the intermediate portion and the both end portions extending in a direction generally perpendicular to the intermediate portion. A brake band having a circular arc approximately equal to the diameter of the brake drum.