JPH0158375B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a wear limit warning device for warning a driver that the friction pads of a vehicle disc brake have worn down to their permissible limit.

BACKGROUND ART A type of disc brake for vehicles includes (a) a disc rotor that rotates integrally with the wheels of the vehicle, (b) a friction material that faces the friction surface of the disc rotor, and a friction material that is fixed to the back surface of the friction material. (c) an actuator for pressing the friction pad against the friction surface of a disc rotor; (d) a disc rotor; is fixed to a non-rotating member near the disc rotor, supports the friction pad so as to be movable in a direction perpendicular to the friction surface of the disc rotor, and
The friction pad has a torque receiving surface that receives rotational torque of the friction pad during braking by contacting with the side end surface of the friction pad, and a recess formed in the torque receiving surface to accommodate the ear portion, and However, there are some that include a torque member that forms a gap between the tip end surface of the ear portion and the gap that does not disappear even when a brake is applied.

It is also already known to attach a contact member to the back plate of a friction pad in order to warn the driver that the friction material of the friction pad has worn to its wear limit. When the friction material wears down to its wear limit, the contact member makes contact with the disc rotor and the sound generated is used as an alarm sound.

Problems to be Solved by the Invention However, conventional alarm devices of this type are not sufficiently effective because the alarm sound is low or the frequency is similar to surrounding noise, making it difficult to distinguish clearly. I couldn't do it. It is conceivable to make the alarm sound louder by increasing the contact force of the contact member to the disc rotor, but this is not desirable because the disc rotor may be damaged by the contact member.

In view of the above circumstances, the present invention aims to provide a wear limit warning device that can generate a warning sound that can be clearly distinguished from surrounding noise while minimizing the contact force of a contact member to a disc rotor. This was done with this in mind.

Means for Solving the Problems The gist of the present invention is to provide a disc brake that includes (a) a disc rotor, (b) a friction pad, (c) an actuator, and (d) a torque member in which the friction material reaches its wear limit. The wear limit warning device, which alerts the driver to the occurrence of abrasion, consists of (i) a groove formed on the tip of the ear part extending in the thickness direction of the back plate, and (ii) a band-shaped spring material. A fixed part comprising an alarm member attached to the ear part of the plate, and the alarm member is fixed to the ear part in a state that it cannot move in the width direction of the groove by being fitted into the groove of the ear part. and a vibrating part that extends from the rear of the back plate toward the friction surface of the disc rotor through a gap that does not disappear even when the brake is applied, and whose tip reaches the wear limit surface of the friction material. , a spring part that connects the vibrating part and the fixed part at the rear of the back plate, and elastically presses the vibrating part against either the side face of the back plate or the side face of the torque member, which face each other with the space between them. Further, a protrusion is provided on either one of the side surface of the back plate and the side surface of the torque member and the vibrating section to define the contact position of the vibrating section to one point at least in the longitudinal direction of the vibrating section. This is because we have established

The side surface of the back plate and the side surface of the torque member may be the surfaces of the back plate and the torque member themselves, respectively, or may be the surfaces of the other member if those surfaces are covered by another member.

Operation In the friction pad wear limit warning device configured as described above, when the friction pad wears to the wear limit, the front end of the vibrating portion of the vibrating member comes into contact with the friction surface of the disc rotor and vibrates. The vibrating part extends through the gap formed between the back plate and the torque member that does not disappear even when the brake is applied, and the elastic force of the spring part causes vibration between the back plate side surface and the torque member side surface. The vibrating member is pressed against one side, and the contact position in the longitudinal direction of these vibrating parts is defined by the protrusion at one point, so the vibrating member stably vibrates in a mode using the protrusion as a node. The frequency can be changed arbitrarily by changing the distance between the tip of the vibrating part and the protrusion.

Moreover, the fixing part is fitted into the groove formed on the tip of the ear, so despite the presence of the fixing part, a sufficient space between the ear and the recess is ensured. It is easy to do. Since the ear and the recess function to guide the movement of the friction pad, it is necessary that they fit over a certain amount.On the other hand, there is a vibration part between the ear and the recess. A gap large enough to allow passage is required, so if the fixing part is not fitted into the groove of the ear part, it will be necessary to deepen the recess by the amount of the fixing part, and the torque member will not fit. In order to ensure rigidity, it is unavoidable that the torque member be made large, and depending on the surrounding circumstances, it is difficult to make the torque member large in size. This inconvenience can be avoided by forming a groove and fitting the fixing part into the groove.

In addition, in order to make the vibrating part vibrate stably, it is necessary to position the vibrating part accurately even in the parallel direction between the two, so that it does not come into contact with anything other than the protrusions. By forming a groove on the tip surface of the ear and fitting the fixing part into the groove, the fixing part can be prevented from moving in the width direction of the groove, and the vibrating part can be accurately positioned within the gap. It's convenient.

Effects of the Invention As described above, the vibrating part of the vibrating member vibrates stably in a specific mode using the protrusions as nodes, so even if the contact force of the vibrating part to the disc rotor is small, a sufficiently loud alarm sound can be generated. can be obtained. Moreover,
The frequency of the vibrating part can be changed arbitrarily by changing the distance from the protrusion to the tip, so it is possible to obtain a high-frequency alarm sound that is different from surrounding noise. It is possible to reliably warn the driver that the wear limit has been reached.

Moreover, since the fixing part of the vibrating member is fitted into the groove formed on the tip surface of the ear, sufficient space can be created between the ear and the recess while avoiding the increase in the size of the torque member. In addition, the vibrating part is accurately positioned even in the direction parallel to the gap, and there is no possibility of it coming into contact with the side wall of the recess.
This provides the effect of ensuring stable vibration of the vibrating part.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

In FIGS. 1 and 2, 10 is a disc rotor that rotates together with the wheels and has a pair of friction surfaces 12, 1.
It is equipped with 4. Friction materials 16 and 18 are provided on both sides of this rotor 10, and a back plate 2 is fixed to the back surface of these materials.
An outer pad 24 and an inner pad 26 are provided. These friction pads 24 and 26 (hereinafter simply referred to as pads) are loosely fitted into a notch 28 provided in the center of the torque member 27 and are movable in a direction perpendicular to the friction surfaces 12 and 14 of the disc rotor 10. The torque member 27 receives the rotational torque applied to the pads 24 and 26 during braking. The torque member 27 is fixed to an axle tube or the like (not shown), and includes opposing plate portions connected across the outer periphery of the disc rotor 10 in order to support pads 24, 26 and a caliper 30, which will be described later. There is.

The caliper 30 includes a cylinder part 32 facing the inner pad 26, a reaction part 34 facing the outer pad 24, and a bridge part 35 connecting the cylinder part 32 and the reaction part 34, and extends over the pair of pads 24 and 26. It is located in A piston 36 is slidably fitted into the cylinder portion 32, and a piston 36 is slidably fitted into the cylinder portion 32.
4 is bifurcated, and each branched portion is disposed outside the back plate 20. And this Calipa 3
Reference numeral 0 denotes a fitting hole formed at the tip of an arm (not shown) extending from both sides thereof, and a torque member 2.
It is supported movably in a direction parallel to the axis of the rotor 10 by fitting with a slide pin (not shown) protruding parallel to the axis of the disk rotor 10 at 7 .

As shown in FIG. 3, U-shaped grooves 39 extending in the thickness direction of the back plate 20 are formed in the lower portions of both ends of the back plate 20 of the outer pad 24 (portions on the side closer to the axis of the rotor 10). A pair of ears 37 protruding in the circumferential direction of the rotor 10 is provided, and a band-shaped spring 38 serving as a vibrating member is attached to the ears 37 as shown in FIGS. 4 and 5. It is being A substantially U-shaped fixing part 40 is provided at one end of the spring 38, and this fixing part 40 has a fitting part 41 that extends along the groove 39 and has the same width as the groove 39.
Wide portions 43 facing each other on both sides of the insertion portion 41
The fitting portion 41 is fitted into the groove 39, and the wide portion 43 is fixed to the ear portion 37 so as to fit between the front and rear surfaces of the ear portion 37. An arrow 45 indicating the rotational direction of the rotor 10 is punched out in the center of the wide portion 43 on the rear side (the side far from the rotor 10) to prevent incorrect attachment of the spring 38. The spring 38 has a first bent part 42 which is bent in a U-shape at the rear side of the back plate 20 following the fixed part 40, and a U-shaped part which is bent in a direction substantially perpendicular to this first bent part 42. The second curved
a bent portion 46 and an ear portion 37 from this second bent portion 46;
and the torque member 27, and extends toward the disc rotor 10, and its tip is connected to the friction pad 2.
4, and a protrusion 50 that protrudes toward the torque member 27 at a portion transitioning from the second bent portion 46 to the vibrating portion 48.
is provided. Note that the spring 38 is bifurcated in the vicinity of the protrusion 50. First bent part 42
and the second bent portion 46 connects the protrusion 50 to the torque member 27.
It has a function of holding the vibrating part 48 while allowing the vibrating part 48 to escape when the vibrating part 48 receives an unreasonable force from the disk rotor 10. 46 forms a spring portion.

On the other hand, as shown in FIG. 6, a recess 47 for accommodating the ear 37 is formed in a portion of the torque member 27 that faces the ear 37 of the back plate 20. An anti-rattling spring 56 is secured to the inner end that includes the recess 47. The anti-rattling spring 56 functions to ensure smooth sliding of the pad 24 and prevent rattling of the pad 24 when the vehicle is running, and is a plate-shaped portion 5 extending along the inner end surface of the torque member 27.
2 is brought into contact with the protrusion 50 of the vibrating section 48 that is urged. Tongues 58 are provided on both sides of the plate-shaped portion 52 to sandwich the torque member 27, and a spring is provided below the pad 24 (on the axis side of the rotor 10) to bias the pad 24 in the upward direction. A section 54 is provided.

The structure around the other ear 37 of the pair of ears in the outer pad 24 is the same as that described above, except that the strip-shaped spring 38 is not provided, and furthermore, the inner pad 26 side has the same structure as the outer pad 37. Since it is symmetrical with No. 24 and has a similar configuration, a description thereof will be omitted.

Next, the operation of the apparatus having the above configuration will be explained.

When braking oil pressure is supplied to the oil chamber 64 of the cylinder portion 32 during braking, the piston 36 is pushed out and presses the inner pad 26 against the friction surface 14 of the rotor 10. This reaction causes the cylinder section 32 to move in the opposite direction to the piston 36, and the reaction section 34 moving together with this moves the outer pad 24 against the other friction surface 12 of the rotor 10.
to suppress rotation of the rotor 10. In this embodiment, the caliper 30 functions as an actuator.

As the number of brake applications increases, the friction material 1 in the outer pad 24 and the inner pad 26 decreases.
6 and 18 gradually wear out from the contact surface with the rotor 10, and eventually reach a wear limit. When the friction material 16 reaches its wear limit, the tip of the vibrating part 48 moves as shown by arrow D in FIG.
This results in contact with the disk rotor 10 rotating in the direction shown. Then, the vibrating section 48 is vibrated with the disk rotor 10 due to the so-called stick-slip phenomenon, and generates a large, mainly high frequency sound (treble). This high-pitched sound is a beeping sound with a higher frequency than normal vehicle noise, so it is an extremely effective warning sound and allows the driver to easily notice the wear of the friction pads 24 and 26. . Since the vibrating part 48 is held by the first bending part 42 and the second bending part 46 so that the contact state between the vibrating part 48 and the disk rotor 10 is not strained, the vibrating part 48 is in contact with the disk rotor 10. The surface of the disc rotor 10 is hardly scratched.

Since the rotor 10 rotates in the direction shown by arrow D in FIG. 5 when the vehicle moves forward, a rotational torque in the same direction is generated in the outer pad 24 when the brake is applied. This rotational torque is received by the torque member 27 when the side end surface of the back plate 20 and the torque receiving surface of the torque member 27 come into contact with each other via the plate-shaped portion 52 of the rattling prevention spring 56.
Even in this case, the vibrating section 48 is not strongly pinched between the tip end surface of the ear section 37 and the plate-like section 52. The ear portion 37, the recess 47, and the plate portion 52 are arranged so that the gap between the tip end surface of the ear portion 37 and the plate portion 52 covering the inner surface of the recess 47 does not disappear even when the brake is applied. The dimensions have been determined. That is, in this embodiment, there is a space between the tip end surface of the ear portion 37 as the side surface of the back plate and the inner surface of the plate portion 52 as the side surface of the torque member, which does not disappear even when the brake is applied. is formed, and a plate-shaped portion 48 extends from the rear of the back plate 20 toward the disk rotor 10 through the gap between the two.

Furthermore, since the spring 38 is positioned in the vertical direction in FIG. 52 that covers the side wall of the recess 47. In the end, the vibrating part 48 passes through the gap without contacting anything other than the protrusion 50 contacting the plate-like part 52, and when the tip of the vibrating part 48 comes into contact with the rotor 10, the protrusion 50 It vibrates stably in a mode with nodes. As a result, the above-mentioned "beep" alarm sound is generated, and the frequency of this alarm sound is
This can be changed by changing the length from the tip of 8 to the protrusion 50.

Further, in the above device, as described above, a groove 39 is provided in the ear portion 37 of the back plate 20, and a fitting portion 41 of the same width of the spring 38 is fitted into this groove 39. It is also possible to attach the spring 38 to the ear portion 37 without providing the fitting portion 39 so that the portion corresponding to the insertion portion 41 comes into contact with the tip end surface of the ear portion 37. However, in this case, the tip end surface of the ear portion 37 is connected to the back surface of the fitting portion 41 (the pad 2
4), or the depth of the recess 47 must be increased by a corresponding amount, both of which lead to the following problems.

That is, when the distal end surface of the ear 37 is retracted, the protruding length (l in FIG. 6) of the ear 37 becomes correspondingly shorter, and the torque member 27 at the ear 37 becomes shorter.
This will accelerate wear at the contact area. The frictional force that acts between the pad 24 and the rotor 10 when the brake is applied strongly presses the trailing side end surface of the pad 24 against the torque member 27, and also causes the pad 24 to move around the rotor around the area supported by the torque member 27. It has the effect of rotating toward the outer circumference of 10. This rotational movement of the pad 24 is prevented by the upper surface of the ear 37 (the surface far from the center of the rotor 10) coming into contact with the lower surface of the recess 47. The upper surface and the lower surface of the recess 47 are strongly pressed during braking. Moreover, the pad 24 and the torque member 2
In this state, the contact portion between the upper surface of the ear portion 37 and the lower surface of the recess 47 is likely to wear out because the portion 7 is moved relative to the surface of the ear portion 37 due to the vibration of the brake. Further, even when the brake is not applied, these contact surfaces are pressed against each other by the elastic force of the anti-rattling spring 56, and slide or repeatedly collide with the vibration of the brake. Therefore, this also causes the contact surface between the ear portion 37 and the recess 47 to wear out, and if the protruding length of the ear portion 37 is short, this contact area will inevitably become smaller and this wear will be accelerated. It is.

On the other hand, if the protruding length of the ear portion 37 is not shortened and the recess 47 is deepened by a corresponding amount, this problem will not occur, but the deeper the recess 47 is, the more the rigidity of the torque member 27 will be increased. In addition, machining of the recess 47 becomes difficult, resulting in problems such as an increase in machining cost and a decrease in productivity.

In contrast, in the above device, the spring 38 can be mounted without shortening the ears 37 or increasing the depth of the recess 47 by fitting the base plate 41 of the spring 38 into the groove 39. , the above-mentioned problems do not occur.

Moreover, the fitting portion 4 in the groove 39 and the spring 38
1 have the same width and are fitted and fixed over a predetermined width, and together with the stable clamping action of the wide portion 43, no displacement occurs even when the vibrating portion 48 is activated.

In the above embodiment, an example was shown in which the protrusion 50 was provided on the vibrating part 48 of the spring 38, but the protrusion 50 can be attached to either the rattling prevention spring or the fitting part 41 of the strip-like spring 38.
Or the back plate 20 of the pad 24 or the torque member 27
It goes without saying that it is possible to directly provide one of the two.

Although the present invention has been described above with reference to a few embodiments, the present invention is not limited to those described in these embodiments, and various modifications may be made without departing from the spirit of the present invention. It is something.

For example, the vibrating part 48 may be brought into contact with the flat friction surface 14 of the disc rotor 10, but the surface of the disc rotor 10 that the vibrating part 48 comes into contact with may be provided with an uneven part that actively excites the vibrating part 48. There is no problem. In this case, there is an advantage that the alarm sound generated by the vibrating section 48 can be further enhanced.

In the above-mentioned embodiment, the strip spring 38 is provided at one of the ears 37 of the inner pad 26 and the outer pad 24, but the ear 37 on the side that wears more is provided.
7, or may be provided only on one side of the pad, or may be provided on both ears 37.

Furthermore, when the vibrating section 48 comes into contact with the disk rotor 10, the projection section 50 resists the biasing force of the bending sections 42 and 46 and moves away from the abutting section in a direction (in FIG. 5, the direction is opposite to the D direction). The rotational direction of the disk rotor 10 may be determined in the direction of .

[Brief explanation of drawings]

1 and 2 are a side sectional view and a front sectional view of a disc brake including a wear limit warning device according to an embodiment of the present invention, respectively, and FIG. 3 is a perspective view of a spring in FIGS. 1 and 2, FIG. 4 is a perspective view of the main parts showing an enlarged view of the periphery of the back plate lug in FIGS. 1 and 2;
FIGS. 5 and 6 are a sectional view and a rear view of the main parts, respectively, showing the periphery of the spring in FIGS. 1 and 2 on an enlarged scale. 10: Disc rotor, 16, 18: Friction material,
20, 22: Back plate, 24: Outer pad, 26:
Inner pad, 27: Torque member, 37: Ear part,
38: Spring, 39: Groove, 40: Fixed part, 42: First bent part, 46: Second bent part, 48: Vibrating part, 5
0: protrusion, A: wear limit surface.

Claims (1)

[Scope of Claims] 1. A disc rotor that rotates integrally with the wheels of a vehicle, a friction material facing the friction surface of the disc rotor, and a back plate fixed to the back plate of the friction material, and a friction pad having an ear protruding laterally from a side end surface of the back plate; an actuator for pressing the friction pad against the friction surface of the disc rotor; and an actuator fixed to a non-rotating member near the disc rotor, movably in a direction perpendicular to the friction surface of the disc rotor, and a torque receiving surface that receives the rotational torque of the friction pad during braking by contacting with the side end surface of the friction pad, and a torque receiving surface thereof. A torque member having a recess formed therein to accommodate the ear, and the recess forming a gap between the recess and the tip surface of the ear that does not disappear even when a brake is applied. A disc brake comprising: a device that generates an alarm sound when the friction material is worn to a wear limit, the device comprising: a groove extending in the thickness direction of the back plate on the tip end surface of the ear; and a band-shaped groove. and an alarm member made of a spring material and attached to the ear of the back plate, and the alarm member is fitted into the groove of the ear and cannot be moved in the width direction of the groove. and a fixed part fixed to the ear part, and extends from the rear of the back plate toward the friction surface of the disc rotor through a gap that does not disappear even when the brake is applied, and has a tip end. a vibrating part that reaches the wear limit surface of the friction material; the vibrating part and the fixing part are connected at the rear of the back plate; and the vibrating part is connected to a side surface of the back plate facing each other with the gap between a spring portion that elastically presses against either one of the side surface of the torque member, and a contact position of the vibrating portion on either one of the side surface of the back plate and the side surface of the torque member and the vibrating portion. 1. A wear limit warning device for a friction pad for a disc brake, characterized in that a protrusion is provided to define the vibration pad at one point at least in the longitudinal direction of the vibrating part.