JPS6145386Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a friction pad for a disc brake, and more particularly to a friction pad capable of reducing drag torque when not braking.

In general, a friction pad includes a friction material and a back plate fixed to the back surface of the friction pad, and is placed on both sides of a rotating disk. During braking, a pressing mechanism provided opposite the back surface of the pad is applied to the friction surface of the disk. It is pressed against it and its rotation is suppressed.

However, conventional friction pads tend to suffer from a phenomenon called drag, in which the friction pad remains pressed against the friction surface of the disk with a constant force even when the brake is not in operation. If drag occurs, energy loss due to drag torque,
This causes various problems such as increased wear on the friction pads and deterioration of brake braking ability, and particularly when used in vehicle brakes, leads to deterioration of driving fuel efficiency.

The present applicant has already filed several patents or utility model registration applications (unpublished) in order to solve the problem of friction pad dragging. In summary, a second back plate is provided on the back of the back plate fixed to the friction material, and when braking, the friction material and the back plate move relative to the second back plate in the rotational direction of the disk. At the same time, the friction material and the back plate are pushed up towards the outer periphery of the disc and pushed towards the plate surface of the disc due to the action of the slope formed between both back plates.When the brake is released, the friction material and the back plate are pushed up against the second plate by an appropriate biasing means. The friction material is returned to its original position relative to the back plate to maintain a constant gap between the friction material and the disk.

In order to move the friction material and the back plate as described above with respect to the second back plate, various mechanisms such as engagement between slopes, protrusions and grooves, or engagement between pins and grooves are used. have been proposed and have achieved their objectives,
Since a relatively large frictional force is applied to the engaging portion of these, in terms of ensuring the above-mentioned movement of the friction material and back plate stably and smoothly,
There was still room for further research.

Based on this technical background, the present invention was made for the purpose of providing a friction pad that can solve the problem of dragging when the brake is not activated. The purpose of this invention is to provide a friction pad that can move freely, provide stable braking effectiveness, and secure an appropriate amount of brake clearance when the brake is not in operation.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, reference numeral 10 denotes a disk that has friction surfaces on both sides and rotates together with the wheels, and a caliper 12 is disposed so as to straddle this disk 10. The caliper 12 is fixed to a non-rotating member and has a pair of cylinder portions located opposite the friction surface of the disk 10, into which pistons 14 and 16 are slidably fitted. An outer pad 18 and an inner pad 20 are disposed between the pistons 14 and 16 and the disk 10 and are supported by support pins 22 attached to the calipers 1 and 2. Further, the pads 18 and 20 are urged away from the disk 10 by a V-shaped return spring 24 disposed between them.

As shown in FIGS. 2 and 3, the outer pad 18 includes a friction material 26 pressed against the friction surface of the disk 10, an inner back plate 28 as a first back plate fixed to the back surface of the friction material 26, and a further inner back plate 28. It is provided with an outer back plate 30 as a second back plate that slidably holds this at the back. Although the thickness of the friction material 26 is uniform throughout, the inner back plate 28 and the outer back plate 30
The overlapping surfaces of the two are inclined to each other.
That is, the inner back plate 28 has a back surface 32 having an inclined surface, and the upper part in FIG. 30
In contrast to the back surface 32 of the inner and outer plates 28, the front surface 34 is an inclined surface that is thinner in the lower part and becomes thicker as it moves upwards, and these two inclined surfaces form a sliding surface on which the inner and outer plates 28 slide. It is said to be a moving surface.

The generally rectangular outer back plate 30 is slightly larger than the inner back plate 28, and is bordered on three sides except the lower side, with edges 36 and 38 at both longitudinal ends, and a wider border at the upper end. Base portions 40 are formed and are U-shaped and open downward. The return spring 24 is inserted between a pair of elongated holes 42 at both ends of the base 40 through which the two support pins 22 for moving the outer back plate 30 in a direction perpendicular to the plate surface of the disk 10 are inserted. A pair of mounting holes 43 for mounting and a hole 44 for engaging a friction pad attachment/detachment tool are provided. Note that the mounting hole 43 is formed in the inner back plate 28 and
8 may be directly pushed back by the return spring 24.

Now, between the outer back plate 30 and the inner back plate 28, which is housed in a recess surrounded by the edges 36, 38 and the base 40 with a predetermined gap, there is a pair of links 46 of equal length. are arranged in parallel, and the medial back plate 2
8 is held by this link 46 so as to be slidable diagonally upward relative to the outer back plate 30. That is,
A recess 48 is formed below the two elongated holes 42 of the outer back plate 30, as shown in an enlarged view in FIG. The outer back plate 30 is pivotally attached by a retaining ring 56. The link 46 includes a plate-shaped portion 58 extending straight from a base end (bent portion) 50 having a through hole for a pin 52 and a hook portion 60 having a circular cross section.
After passing through a pin hole formed in the inner back plate 28, a pin portion 61 formed parallel to the pin portion 61 is inserted into a through hole formed in the plate-like portion 58. The link 46 is formed from a wire material by press working, and is simple and lightweight, yet can connect the inner back plate 28 and the outer back plate 30 with sufficient strength.

In other words, the outer back plate 30 becomes a fixed link, and a pair of rotating links 46 are connected to both ends of the fixed link, and both links 46 are further connected by the inner back plate 28 as a fourth link, so that the whole forms a parallelogram. A four-link mechanism is constructed, and when the inner back plate 28 attempts to move in the x direction in FIG. The object is moved diagonally upward, that is, in a direction that has components in both the x and y directions.

This inner back plate 28 is biased by a leaf spring 62 in a direction opposite to the x direction. One side of the U-shaped leaf spring 62 is fixed to the edge 38 of the outer back plate 30,
The other side, that is, the action part is one side end 6 of the inner back plate 28.
It is fitted into an elongated recess 66 formed in 4, and the tip is brought into contact therewith with a certain preload.

As a result, the inner back plate 28 is urged diagonally downward by the action of the link 46, and a constant gap α is maintained between one side end 64 and the edge 38 of the outer back plate 30. On the other hand, the other side end 68
is pressed against the edge 36 of the outer back plate 30, and the lower surface of the friction material 26 is kept in alignment with the lower surface of the outer back plate 30.

By the way, in this state, the pair of links 46 are attached to the edges 36 or 38 of the outer back plate 30 at an angle θ, for example, about 30 degrees, and this means that when the links 46 rotate, the inner back plate 28
This is to increase the amount of movement in the y direction, and y
If the amount of movement in the direction is large, the back surface 3 of the medial back plate 28
2 and the front surface 34 of the outer back plate 30, the inner back plate 28 is pushed out toward the front side to which the friction material 26 is fixed.

Note that the inner pad 20 has exactly the same structure as the outer pad 18 described above.

Next, the outer pad 18 configured as described above
The operation of the inner pad 20 will be explained together with the operation of the disc brake.

When the brake fluid is supplied to each cylinder portion of the caliper 12, the pistons 14 and 16 are pushed out, bringing the friction materials of the outer pad 18 and the inner pad 20 into contact with both friction surfaces of the disc 10.

The friction material 26 of the outer pad 18 is the disk 10
When brought into contact with the friction surface of the disc 10, a drag torque acts on the inner and back plates 28 fixed to the friction material 26 to cause them to rotate together with the disc 10.
If the disk 10 is now rotating clockwise (indicated by the arrow) in FIGS. 1 and 2, a drag torque in the same direction acts on the friction members 26 and 28. With the outer back plate 30 being prevented from moving by the torque receiving surface of the caliper 12, the inner back plate 28 tries to rotate in the direction of rotation of the disk 10, but the outer back plate 30 and the inner back plate 28 are connected by a pair of links 46. Because of the connection, the link 46 is rotated around the pin 52, causing the inner back plate 28 to generate a radial motion component of the disk 10 shown in the y direction in FIG. In FIG. 2, it is moved diagonally upward to the right against the biasing force of the leaf spring 62, and is eventually moved together with the friction material 26 in a direction away from the axis of the disk 10. In this way, the movement component of the disk 10 in the radial direction is obtained by the link 46, so that the movement of the inner and back plates 28 is performed smoothly and reliably.

The inner back plate 28 is moved obliquely upward, and the inner back plate 28 is moved diagonally upward, and the inner back plate 28 is moved diagonally upward, and the back side 32 of itself and the front face 34 of the outer back plate 30 are moved.
Due to the action of the inclined sliding surface formed on the surface, the friction material 26 is pushed out toward the front side to which it is fixed. In other words, the overall thickness of the outer pad 18 increases, and as a result, the thickness of the disk 10 and the outer pad 1 increases.
The contact surface pressure between the piston 8 and the piston 16 is increased, and the braking effect is about to appear.

The movement of the inner back plate 28 is caused by the gap α between the side edge 64 and the outer back plate edge 38 disappearing, and the side edge 64 coming into contact with this edge 38, thereby causing the friction material 26 to move. The inner and outer plates 28 are stopped at a position farthest from the axis of the disk 10.

At this time, the friction material 26 and the inner back plate 28 of the inner pad 20 are moved in exactly the same way to a position apart from the axis of the disk 10, and in this state, the friction material 26 and the inner back plate 28 of the outer pad 18 and the inner pad 20 are moved in the same manner. Since the outer back plate edge 38 completely prevents rotation, from then on, as the braking fluid pressure in each cylinder increases, it is pressed more strongly against the disk 10 and its rotation is suppressed.

Next, when the brake is released, the braking fluid pressure in each cylinder is reduced, resulting in compressive deformation of the pads 18 and 20 and expansion deformation of the caliper 12 (deformation in which opposing cylinder parts are moved away from each other). The elastic deformation is recovered and piston 1
4 and 16 are pushed back into the cylinder section. The friction material 26 of the outer pad 18 and the inner pad 20 has almost completely recovered from these elastic deformations.
The inner and outer plates 28 are released from the twisting torque of the disk 10 and are pushed back to the original position, that is, the position closest to the disk axis by the restoring force of the leaf spring 62. However, as described above, the front surface 34 of the outer back plate 30 on which the inner back plate 28 slides is inclined so as to move away from the disk friction surface as it approaches the disk axis, and the back surface 32 of the inner back plate 28
Since the inner and outer pads 18 and 20 are also inclined accordingly, when the inner and inner pads 28 are returned to their original positions, the thicknesses of both the outer and inner pads 18, 20 will be reduced by the amount increased during braking. The pressure of both the outer and inner pads 18, 20 against the disk 0 is reliably released, and dragging of the pads 18, 20 when the brake is not activated is effectively prevented.

Moreover, this gap will be used when pad 18 is applied during the next braking.
Since the inner and outer plates 28 of 20 are removed by being moved again to the position farthest from the disk axis, the amount of fluid consumed by the cylinder portion during braking increases in order to create this gap. There is no danger at all; on the contrary, the amount of liquid consumed is reduced by the amount of shakeback or knockback of the piston.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be implemented with various modifications.

In the above embodiment, an example was explained in which the friction pad according to the present invention was used in a caliper fixed type disc brake, but of course it can also be suitably applied to a caliper floating type disc brake, and when used in a caliper fixed type disc brake. Almost the same effects can be obtained.

In this case, it is also possible to apply the present invention only to the friction pads disposed on the reaction side where drag is particularly likely to occur, thereby reducing the drag of the entire brake while minimizing the increase in cost. Can be done.

Furthermore, the four-link mechanism formed by the first and second back plates and a pair of links is not necessarily limited to a parallelogram-shaped four-link mechanism; In order to restrict the movement limit of the first back plate (inner back plate) with respect to ), it is also possible to make the first back plate itself come into contact with the torque member.

Furthermore, in order to return the first back plate to its original position when the brake is not activated, an elastic member may be provided to bias the first back plate toward the axis of the disk. In short, it is sufficient to bias the first back plate so that it is moved in a direction approaching the axis of the disc rotor by the action of the elastic member and the link when the brake is released.

In addition, the inclined sliding surface formed between both back plates that creates a certain pad clearance with the disk when the brake is not activated does not necessarily have to be inclined along the radial direction of the disk. It is also possible to incline it so as to substantially match the moving direction of the back plate 1. In addition, although I will not specifically explain each individual in detail, the present invention includes the following:
Of course, various changes can be made.

In summary, the present invention is a friction pad that is brought into sliding contact with a disc rotor to suppress its rotation, and includes (1) a friction material that comes into contact with the disc rotor to generate a frictional force, and (2) a friction pad made of this friction material. a first back plate fixed to the back surface; (3) a second back plate that slidably supports the first back plate from behind; and (4) together with these first and second back plates. 1 forming a four-link mechanism and generating a motion component in the radial direction of the disc rotor in the first back plate when the first back plate slides relative to the second back plate in the rotational direction of the disc rotor; a pair of links, and (5) a sliding surface formed between both back plates with an inclination such that when this radial motion component occurs, the first back plate is pushed toward the front side to which the friction material is fixed. (6) an elastic member that always urges the first back plate to move in a direction toward the axis of the disk rotor.

Therefore, when the friction pad according to the present invention is installed on the brake, the first
When the friction material fixed to the back plate is lightly pressed against the disk, the first back plate rotates with the disk and moves away from the disk axis, including a radial motion component of the disk, due to the action of the pair of links. direction, and at that position is fully pressed against the disk to suppress its rotation. When the brake is released, the first back plate is returned to its original position relative to the second back plate by the urging force of the elastic member, and at this time, the presence of the inclined sliding surface formed between both back plates causes friction. The pad is reliably released from the pressing force against the disk, and the occurrence of dragging is prevented. Moreover, various problems such as early wear of friction pads, energy loss, and deterioration of braking performance due to brake overheating are all eliminated, and especially when used in a vehicle, this greatly contributes to improving driving fuel efficiency.

Furthermore, when the first back plate tries to rotate with the disk, a motion component in the radial direction of the disk is forcibly generated by the pair of links.
There is no fear that the smooth movement of the back plate will be prevented by frictional force, and stable movement is guaranteed, and a reliable braking effect and anti-dragging effect can be obtained.

Note that when the friction material is lightly pressed against the disc during braking and subjected to torque, the thickness of the entire friction pad increases due to the action of the inclined sliding surface between both back plates. One of the effects of the present invention is that the amount of fluid consumed to press the brake against the disk can be reduced, and the operating stroke or operating force of the brake operating member can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an example of a state in which a friction pad according to the present invention is arranged on a disc brake, Fig. 2 is a front view showing an example of the friction pad, and Fig. 3 is a - in Fig. 2. The sectional view, or FIG. 4, is a - sectional view in FIG. 10: disk, 18: outer pad, 20:
Inner pad, 26: Friction material, 28: Inner back plate (first back plate), 30: Outer back plate (second back plate), 32:
Back, 32: Front, 36, 38: Edge, 46: Link, 52: Pin, 62: Leaf spring.

Claims (1)

[Claims for Utility Model Registration] A friction pad that is brought into sliding contact with a disc rotor to suppress its rotation, comprising: a friction material that comes into contact with the disc rotor to generate a frictional force; and a friction pad that is fixed to the back surface of the friction material. a second back plate that slidably supports the first back plate from behind; a four-link mechanism is formed together with the first and second back plates; When the first back plate slides with respect to the second back plate in the rotational direction of the disc rotor, the first
a pair of links that generate a radial motion component of the disc rotor on a back plate of the disc rotor;
a sliding surface formed between the two back plates by tilting the back plate toward the front side to which the friction material is fixed, and the first back plate always approaching the axis of the disk rotor. A friction pad for a disc brake, comprising: an elastic member biased to move in a direction.