JPS621130B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a wear limit warning device that alerts a driver when the friction pads of a vehicle disc brake have worn to the wear limit and need to be replaced.

Conventional technology A disc brake for a vehicle includes a disc rotor that rotates integrally with the wheel, a friction pad that is pressed by an actuator against the friction surface of the disc rotor, and a friction pad that is perpendicular to the friction surface of the disc rotor. The torque member is generally configured to include a torque member movably supported in the direction. The friction pad is composed of a friction material facing the friction surface of the disc rotor, and a back plate fixed to the back surface of the friction material, and the torque member is fixed to a non-rotating member near the disc rotor to brake the disc rotor. It is configured to receive the rotational torque of the friction pad during operation by coming into contact with a part of the side end surface of the back plate.

The friction material of the friction pad wears out as it is used, and when the amount of wear reaches a wear limit, it becomes necessary to replace it. Therefore, a wear limit warning device is used to notify the driver that the friction pad has reached its wear limit.One type of device is a wear limit warning device that comes into contact with the disc rotor and emits an alarm when the friction pad wears down to the wear limit. There is a type in which a band-shaped alarm member that emits the alarm is attached to a friction pad. Various alarm devices of this type have already been proposed, but all of them have the disadvantage that it is difficult to obtain an alarm sound that can be clearly distinguished from surrounding noise. In order to be clearly distinguishable from surrounding noise, a sound of high frequency and considerable volume is required, but it has been difficult to create an alarm system that can produce such a sound. . In order to obtain a high-frequency alarm sound, it is necessary to increase the natural frequency of the part of the alarm member that comes into contact with the disc rotor. If you shorten the length of the vibrating part of an alarm device that is attached to a handle, the amplitude of the vibrating part will become smaller and you will not be able to obtain a sufficiently loud sound. This is because if the plate thickness and plate width of the vibrating part are increased in order to achieve this, the strength of the vibrating part will increase and there is a risk of damaging the friction surface of the disc rotor when it comes into contact with it.

On the other hand, for example, as described in Japanese Utility Model Application Publication No. 55-15411, the alarm member is formed by forming a fixed part fixed to the side end of the back plate of the friction pad and a part connected to the fixed part. The spring part that rotates at the rear position of the friction pad, and the formation between the spring part and the back plate of the friction pad and the torque member disappear during braking (both when the vehicle is moving forward and when the vehicle is moving backward). If the vibrating part extends toward the friction surface of the disc rotor through a gap that does not occur, and the tip reaches the wear limit surface of the friction material of the friction pad, then the vibration part Since the vibrating part is not strongly pinched by other members and is allowed to move due to the elastic deformation of the spring part, the vibrating part will hit the friction surface of the disc rotor too strongly in the event of an alarm, causing damage to the friction surface. or damage to the vibrating part itself. However, in this alarm member, in order to function as an anti-rattle spring that prevents rattling of the friction pad, the direction in which the vibrating part is biased by the spring and the direction in which the disc rotor rotates when the vehicle moves forward are adjusted. Because it is reversed, when the tip of the vibrating part contacts the disc rotor, it is deflected in the direction away from the torque member due to the frictional force between it and the disc rotor, and is moved away from the torque member by the spring part. It vibrates in a mode in which it rotates around the end on the side where it is supported, and because the length of the vibrating part is long, the natural frequency is low, making it difficult to obtain an alarm sound with a sufficiently high frequency.

Therefore, as suggested in Japanese Utility Model Application Publication No. 53-286, the biasing direction of the vibrating part by the spring part is the same as the rotating direction of the disc rotor, so that the vibrating part is aligned with the rotating direction of the disc rotor of the torque member. If it is pressed against the opposing surface, when the vibrating part contacts the friction surface of the disc rotor, it will vibrate in a mode in which the vibrating part rotates with its longitudinal intermediate part supported by the torque member. Since the length from the fulcrum to the tip is short, there is an advantage that a higher frequency can be obtained compared to the one described in the above-mentioned publication.

Problems to be Solved by the Invention However, as described in this publication, when the vibrating part of the alarm member is simply brought into contact with the end face of the torque member, the vibrating part comes into contact with the friction surface of the disc rotor. When vibration starts, the contact point between the vibrating part and the torque member vibrates in a mode in which it is alternately supported by the edge of the end face of the torque member closer to the disk rotor and the edge farther from the disc rotor, and the vibration is stabilized. and it is difficult to obtain a sufficiently loud alarm sound.

Against this background, the present invention provides a friction pad wear limit warning device that does not cause damage to the disc rotor when the warning member comes into contact with the disc rotor, and can stably vibrate at a predetermined frequency. This was done for the purpose of providing.

Means for Solving the Problems The gist of the present invention is to form a protrusion that contacts at least one point in the longitudinal direction of the vibrating part on a member that comes into contact with the vibrating part of the alarm member; The point is that the part that contacts this protrusion is used as a node to stably vibrate at a predetermined frequency.

That is, the wear limit warning device according to the present invention has the following features:
Consisting of a band-shaped spring material, (a) a fixed part fixed to the side end of the friction pad back plate; a spring part formed following the fixed part and bent at a rear position of the friction pad; A vibrating part extends from the spring part toward the friction surface of the disc rotor through the gap formed between the side end surface of the friction pad back plate and the torque member, and the tip reaches the wear limit surface of the friction material. and (b) a member that covers the facing surface, which is the side facing in the rotational direction of the disc rotor, or the outward facing surface of the surface forming the gap between the friction pad back plate and the torque member. and a protrusion that contacts the vibrating part of the alarm member at least at one point in the longitudinal direction of the vibrating part and prevents other parts of the vibrating part from contacting the opposing surface or the member covering it. configured. A part of the side end surface of the back plate of the friction pad comes into contact with the torque member and transmits rotational torque, but there is a gap between another part of this side end surface and the torque member that disappears even during torque transmission. In such cases, the vibrating part is moved through the gap, or if there is no such gap, by intentionally creating such a gap. The protrusion is made to extend toward the torque transmission surface, and the protrusion is formed on the member forming the gap that comes into contact with the vibrating part. This protrusion is formed in a state in which it abuts point-wise at least in the longitudinal direction of the vibrating part to prevent other parts of the vibrating part from coming into contact with the back plate or the torque member, and the vibrating part is moved by the elasticity of the spring part. It is constantly pressed against this protrusion by force. In addition,
It is not essential that the protrusion be formed directly on the friction pad back plate or the opposing surface of the torque member, but the opposing surface may be used as a lining to prevent rust between the back plate and the torque member, or on the fixing part of the alarm member itself. If the cover is covered with other materials, it may be formed on those members.

Function and Effect With this configuration, the vibrating part can stably vibrate using the part that contacts the protrusion as a node, and a loud alarm sound can be obtained.Moreover, the frequency of vibration can be adjusted by changing the formation position of the protrusion. Since the frequency can be set arbitrarily, it is possible to obtain an alarm sound with a frequency that can be clearly distinguished from surrounding noise.

It is also possible to form a protrusion on the vibrating part of the alarm member, but in that case, as the vibrating part comes into contact with the disk rotor and wears out, the length from the protrusion to the tip of the vibrating part changes, and the vibrating part The natural frequency of the alarm changes and the alarm sound changes. On the other hand, if the protrusions are formed on the back plate or the torque member side as in the present invention, even if the vibrating part wears out, the length from the protrusion to the tip of the vibrating part does not change, so such problems do not occur.

Further, especially when the protrusion is provided on the torque member side, there is an advantage that the length from the protrusion to the tip of the vibrating part can be easily increased for reasons that will be explained in detail later in the embodiments.

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,
It is equipped with 14. 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.
A pair of friction pads, an outer pad 24 and an inner pad 26, are provided. These pads 24 and 26 are loosely fitted into a notch 28 provided in the center of the torque member 27 and are supported so as to be movable in a direction perpendicular to the friction surfaces 12 and 14 of the disc rotor 10. Pads 24, 26 from disk rotor 10
The torque member 27 receives the rotational torque applied to the torque member 27 . The torque member 27 is fixed to a non-rotating member such as an axle tube (not shown), and is connected to pads 24, 26 and a caliper 3 (described later).
In order to support the disc rotor 10, the disc rotor 10 is provided with opposing plate-shaped parts connected across the outer periphery of the disc rotor 10.

Caliper 30 as an actuator that presses the pads 24 and 26 against the disk rotor 10
is the cylinder portion 32 facing the inner pad 26
, a reaction part 34 facing the out pad 24 , and a bridge part 35 connecting the cylinder part 32 and the reaction part 34 , and is arranged so as to straddle the pair of pads 24 and 26 . A piston 33 is slidably fitted into the cylinder portion 32, and the reaction portion 34 is bifurcated, with each bifurcated portion being disposed outside the back plate 20. The caliper 30 has a fitting hole formed at the tip of an arm (not shown) extending from both sides thereof, and a slide pin (not shown) protruding from the torque member 27 parallel to the axis of the disc rotor 10. By fitting, rotor 1
It is supported so as to be movable in a direction parallel to the 0 axis.

An ear portion 37 protruding in the circumferential direction of the disk rotor 10 is formed in a portion of the back plate 20 of the pad 24 on the side closer to the axis of the disk rotor 10, and a rectangular ear portion 37 forming a part of the notch 28 of the torque member 27 is formed. is engaged with the small notch 36 of the ear, but one of the ears 3
A band-shaped spring 38, which is an alarm member, is fixed to 7. Although not shown, the inner pad 2
6 is also constructed similarly to the outer pad 24.

As shown in FIGS. 3 and 4, the spring 38 has a fixed portion 40, a first bent portion 42, and a second bent portion 4.
6 and a vibrating section 48. The fixing part 40 is bent into a U-shape in the longitudinal direction and grips the ear part 37, and also has a vertical positioning stopper 39.
It is equipped with First bent part 42 and second bent part 46
Both have a U-shape and are formed in directions perpendicular to each other, one end of the first bent part 42 is connected to the fixed part 40, and the other end is connected to one end of the second bent part 46. The first bent portion 42 and the second bent portion 46 constitute a spring portion that bends in the space behind the back plate 20. A vibrating section 48 is extended from the other end of the second bending section 46 . The vibrating section 48 extends toward the disk rotor 10 through a gap formed between the side end surface of the ear section 37 of the back plate 20 and the opposing surface of the torque member 27. The wear limit surface A of the pad 16 has been reached. During braking, the side end surface above the ear 37 of the back plate 20 comes into contact with the torque member 27 and transmits rotational torque. The length of the ear portion 37 is determined so that the gap formed in the gap does not disappear.

On the other hand, in order to prevent rattling of the friction pads 24 and 26, an anti-rattling spring 56 is provided at the ear portion 37.
They are respectively arranged inside the notch 28 near the . The rattling prevention spring 56 includes a plate-shaped portion 50 extending along the inner end surface of the torque member 27, and an appropriate number of pairs of tongues 52 for sandwiching the torque member 27 are provided on both sides of the plate-shaped portion 50. The plate portion 50 covers the surface of the torque member 27 facing the back plates 20, 22 so as to function as a lining to prevent rust between the back plates 20, 22 of the friction pads 24, 26 and the torque member 27. It is arranged in. A spring portion 54 is provided in a portion of the plate-shaped portion 50 located below the pad 24 (on the axis side of the rotor 10) for biasing the pad 24 in a upward direction to prevent rattling. . Further, a protrusion 58 protruding toward the pad 24 is formed in a portion of the plate-shaped portion 50 located at the bottom of the small notch 36, that is, a portion of the spring 38 facing the side surface of the vibrating portion 48. The vibrating section 48, which is biased by a spring section consisting of the first bent section 42 and the second bent section 46, is always pressed against this protrusion 58.

In addition, FIGS. 3 and 4 show the outer pad 24.
The vicinity of one ear portion 37 is shown, and the spring 38 is not provided near the other ear portion, but other than that, the structure is the same.

In this way, the spring 38 itself is a member with a simple structure, and moreover, the disc brake to which it is attached has a sufficient size between the side surface of the friction pad back plate and the torque member so that it will not disappear even during braking. If the spring 3 has a gap of 300 mm, provide such a gap at that position, or if there is no such gap, provide such a gap at the desired position, and then install the spring 3.
8, it is possible to obtain a simple and inexpensive wear limit warning device.

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 section 32 during braking, the piston 33 is pushed out and the inner pad 26 is pressed against the friction surface 12 of the rotor 10.
to press. Then, due to this reaction, the cylinder part 32
is moved in the opposite direction to the piston 36,
The reaction section 34 that moves together with this presses the outer pad 24 against the other friction surface 14 of the rotor 10 to suppress rotation of the rotor 10.

As the number of brake applications increases, the friction materials 16, 18 in the outer pad 24 and inner pad 26 gradually wear out from the contact surface side with the rotor 10, and reach a wear limit. When the friction material 16 reaches its wear limit, the tip of the vibrating portion 48 of the spring 38 comes into contact with the disk rotor 10 rotating in the direction indicated by arrow D in FIG. Then, the vibrating part 4
8 is stably vibrated using the portion in contact with the protrusion 58 as a node to generate a loud 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 know that the friction pads 24 and 26 have reached their wear limit. Because you can know. 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.

By the way, in the above-mentioned wear limit alarm device, since the protrusion 58 that defines the length l of the vibrating part 48 is provided on the side of the rattling prevention spring 56, it has the feature that the value of l can be selected to be relatively long. There is. To explain more specifically based on FIG. 6, the protrusion 6
0 is replaced with the rattling prevention spring 56 and the vibrating part 48
It is also possible to provide this protrusion 60 on the side of the rattling prevention spring 56 and make the protrusion 60 contact the plate-like part 50 of the rattling prevention spring 56; The length between the side edges (the side farthest from the center) is the maximum, and adjustment is possible only within this range. This is because the protrusion 60 is the pad 24.
If you want to avoid the protrusion 60 hitting the side edge of the plate-shaped part 50 from the rear side and creating resistance when the pad moves, the protrusion 60 should be moved when the pad 24 is initially retracted the most. It is necessary to provide it at a position where it contacts the inner surface of the plate-shaped portion 50 in the state where it is farthest from the rotor 10 (the state shown in FIG. 6), and therefore the length from the projection 60 to the tip of the vibrating portion 48 In other words, the maximum value of l is defined by the distance between the tip of the vibrating part and the side edge of the plate-shaped part 50 (l ₁ in FIG. 6) when the pad 24 is in the most retracted state.

On the other hand, since the protrusion 58 in the above device is provided on the side of the rattling prevention spring 56 whose position does not change throughout the entire wear process of the friction material 16, the length from the protrusion 58 to the tip of the vibrating part 48 is equal to As the pad 24 is worn out, it becomes larger, and its final length, ie, the above l is given by the distance (l ₂ in FIG. 4) between the tip of the vibrating part and the position-fixing projection 58 when the pad 24 is pushed out the most. Even when the protrusion 58 is provided on the rear edge of the plate-shaped portion 50, it is always in contact with the side surface of the vibrating portion 48 and does not impede the smooth movement of the vibrating portion 48, as described above. l is pad 24
The distance between the tip of the vibrating part 48 and the rear edge of the plate-shaped part 50 in the state in which it is pushed out the most can be selected to be longer than that shown in FIG. It is possible to change the This makes it easy to generate an optimal warning sound in relation to changes in the frequency of vibration and noise due to differences in vehicle types, etc., and other circumstances, and the warning effect can be further enhanced. 7th
8, the protrusions 62 and 68 are shown in FIGS. 3 to 5.
This example shows an example in which the device is installed on the front side and the rear side of the position shown in the figure (approximately the center in the thickness direction of the torque member 27), which results in a higher alarm sound and a lower alarm sound than the device shown in the figure. are generated respectively.

Next, FIG. 9 shows still another embodiment of the present invention, in which a protrusion 70 is provided on the fixing portion 40 of the spring 72. In this embodiment, the rotation direction of the motor 10 is the direction shown by E in FIG. According to this embodiment, when the spring 72 is fixed to the back plate 20 and is fitted into the torque member 27, the vibration part 48 is not opened, so there is an advantage that assembly is easy. Further, this embodiment is suitable when the length from the protrusion 70 to the tip of the vibrating section 48 is desired to be shortened.

In the above embodiment, an example was explained in which the protrusion was provided on either the rattling prevention spring or the strip-shaped spring, but such a protrusion can also be provided directly on either the back plate of the pad or the torque member. It goes without saying that there is.

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 gist of the present invention. It is.

For example, the vibrating portion 48 may be brought into contact with the flat friction surface 14 of the disc rotor 10;
The surface of the disk rotor 10 with which the rotor 8 contacts may be provided with an uneven portion that actively excites the vibrating portion 48 . In this case, there is an advantage that the alarm sound generated by the vibrating section 48 can be further enhanced.

In the embodiment described above, the spring 38 is attached to one ear 37 of the inner pad 26 and the outer pad 24.
However, the ear portion 37 on the side with a lot of wear
Alternatively, it may be provided only on one side of the pad, or may be provided on both ears 37.

[Brief explanation of the drawing]

1 and 2 are side sectional views and front sectional views of a disc brake including a wear limit warning device which is an embodiment of the present invention, and FIGS. 3 and 4 are shown in FIGS. 1 and 2. FIG. 2 is a rear view and a plan sectional view showing an enlarged main part of the disk portion;
FIG. 5 is a perspective view of essential parts of the rattling prevention spring shown in FIGS. 1 to 4. FIG. FIG. 6 is an explanatory diagram for explaining the advantages of the wear limit warning device shown in FIGS. 1 to 5, and FIGS. 7 and 8 are main parts of the wear limit warning device which is another embodiment of the present invention. FIG. 9 is a plan sectional view including a wear limit warning device which is still another embodiment of the present invention. 10: Disc rotor, 16, 18: Friction material,
20, 22: Back plate, 24: Outer pad, 26:
Inner pad, 27: Torque member, 38, 72:
Spring, 40: Fixed part, 42: First bending part, 46:
Second bent portion, 48: Vibration portion, 56: Rattling prevention spring, 58, 60, 62, 68, 70: Projection portion, A: Wear limit surface.

Claims (1)

[Scope of Claims] 1. A friction pad comprising a disc rotor that rotates integrally with a vehicle wheel, a friction material facing the friction surface of the disc rotor, and a back plate fixed to the back surface of the friction material. an actuator that presses the friction pad against the friction surface of the disc rotor; an actuator that is fixed to a non-rotating member near the disc rotor and supports the friction pad so as to be movable in a direction perpendicular to the friction surface of the disc rotor; , the rotational torque of the friction pad during braking is received by contacting a part of the side end surface of the back plate of the friction pad, and a gap that does not disappear even during the contact is provided on the side. A device for generating an alarm sound when the friction material wears to the wear limit in a disc brake including a torque member formed between the end face and another portion of the end face, the device being made of a strip-shaped spring material, A fixing part fixed to a side end of the back plate, a spring part formed subsequent to the fixing part and rotating at a rear position of the pad, and a friction member passing from the spring part through the gap to the disc rotor. an alarm member having a vibrating part that extends toward the surface and whose tip reaches the wear limit surface of the friction material, and of the surface forming the gap between the back plate and the torque member, the disc rotor The vibrating part is formed on a facing surface on the side opposite to the rotational direction or a member covering the facing surface, and is in contact with the vibrating part at least at one point in the longitudinal direction of the vibrating part so that other parts of the vibrating part are not affected. The vibrating part is always pressed against the protrusion by the elastic force of the spring part, and the tip of the vibrating part is connected to the disk. 1. A friction pad wear limit alarm device for a disc brake, characterized in that, when the vibrating section contacts the rotor, the vibrating section vibrates at the contact section of the protrusion to emit an alarm sound.