JPS627864Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a disc brake, and in particular to reducing the drag torque during non-braking.

2. Description of the Related Art A disc brake is a type of brake that suppresses the rotation of a rotating disc rotor by pressing a pair of brake pads against friction surfaces formed on both sides of the disc rotor, and is widely used for vehicles.

However, disc brakes have the disadvantage that they tend to cause a phenomenon called drag, in which the brake pads remain pressed against the friction surface of the disc rotor with a constant force even when not braking. If drag occurs, the disc rotor will rotate under constant drag torque, and the loss of energy will be an amount that cannot be ignored. Regarding vehicle brakes, it is even said that reducing drag torque during non-braking is the key to achieving low fuel consumption.

Additionally, this dragging increases wear on the brake pads, shortening their lifespan, and also causes brake overheating.

Therefore, as described in, for example, Japanese Utility Model Application No. 172175/1983, it has been proposed to provide a retract spring between a pair of brake pads to increase the distance between them. If the distance between the pair of brake pads is widened when the brake is not applied, it becomes less likely that the pads remain in contact with the friction surface of the disc rotor, making it possible to reduce drag torque.

However, when a retract spring is disposed between a pair of brake pads, it is essential to prevent the brake pads from being infinitely retracted by the biasing force of the retract spring. Moreover, the backward limit position needs to be brought closer to the disc rotor as the friction member of the brake pad wears. For this reason, for example, a piston seal that maintains fluid tightness between the piston for pressing the brake pad against the disc rotor and the caliper cylinder is disposed in a groove formed on the cylinder side, and the piston seal maintains a constant friction. In addition to holding the piston by force, the piston is allowed to move forward relative to the cylinder portion during braking, while storing elastic force to return the piston to its original position. If the friction member wears out and the brake pad is no longer pressed against the disc rotor with sufficient force even if the piston seal is deformed to its deformable limit, frictional force will build up between the piston and the piston seal. A relative movement occurs against this, and the wear of the friction member is canceled out.

Problems to be solved by the invention A backward limit regulating means that defines the backward limit of the brake pads like the above-mentioned piston seal and advances the backward limit position as the friction member wears; If used in combination with a retract spring that acts to widen the gap, it is possible to reduce brake drag, but even so, after a particularly high brake fluid pressure is supplied to the cylinder, such as during sudden braking, , it is difficult to completely prevent the occurrence of dragging. especially,
When high braking fluid pressure is supplied, the amount by which the caliper is elastically deformed so that the distance between the parts facing each of its pair of brake pads is widened, and the amount of compressive elastic deformation of the friction member of the brake pads is increased compared to normal. This is because the amount of relative movement between the piston and the cylinder section becomes larger than normal, and the brake pad is moved forward from its retraction limit position even though the friction member of the brake pad is not worn out. If the total amount of elastic deformation of the caliper cylinder and friction members exceeds the amount of elastic deformation of the piston seal or other retraction limit regulating means, dragging will naturally occur, but even if this is not the case, the brake clearance during non-braking will become smaller. Generally speaking, dragging is more likely to occur.

If the brake clearance is set to a value that exceeds the sum of the amount of elastic deformation of the caliper and friction members during sudden braking, the above situation will not occur, but in reality, such a brake It is often difficult to design. If you simply increase the brake clearance, the stroke of the piston required to eliminate it will increase, and the stroke of the brake pedal to operate the piston will increase, reducing brake operability. It is not possible to simply increase the brake clearance, and there is also a limit to increasing the rigidity of calipers and the like.

As detailed above, the present invention was developed with the objective of effectively preventing the drag that occurs even in disc brakes equipped with retract springs, which is difficult to prevent after sudden braking. be.

Means for Solving the Problem In order to solve this problem, the present invention provides (a) a rotating disc rotor having friction surfaces on both sides, and (b)
A pair of brake pads are disposed on both sides of the disc rotor to face the friction surfaces, and (c) an actuator operated by hydraulic pressure is provided so as to straddle the pair of brake pads and the disc rotor. (d) a caliper disposed between the pair of brake pads, having both ends engaged with each brake pad, and causing each brake pad to move away from the disc rotor; (e) a retract spring that applies a biasing force; and (e) a limit to which the pair of brake pads can be retracted by the biasing force of the retract spring. A disc brake equipped with a rearward limit position regulating means that allows each of the pair of brake pads to approach the disc rotor, comprising: a friction member facing the friction surface of the disc rotor; a back plate fixed behind the friction member; Further behind the back plate, the holding member holds the back plate so as to be movable in a direction substantially parallel to the friction surface of the disk rotor, and has a guide surface for guiding the movement of the back plate. The back plate moves from its original position while being guided by the guide surface based on the entraining torque received when the friction member contacts the friction surface of the disc rotor. Accordingly, the friction member and the back plate are inclined with respect to the friction surface of the disc rotor in a direction in which the friction member and the back plate are pushed toward the disc rotor, and a biasing means is provided for biasing the back plate toward the original position, and
Both ends of the retract spring are engaged with each of the back plates of the pair of brake pads to press the back surfaces of each back plate against the sliding surface of the holding member and urge the holding member away from the disc rotor. It is something.

Operation When the disc brake configured as described above is operated, the back plate is guided by the guide surface and pushed toward the disc rotor by the rotational torque received when the friction member contacts the disc rotor. This results in an apparent increase in the thickness of the brake pad. When the brake is released, the back plate is moved toward the original position by the biasing means, and the thickness of the brake pad is apparently reduced.

Furthermore, the increased thickness of the brake pad is maintained until the operating force of the actuator becomes sufficiently low when the brake is released, and the apparent thickness of the brake pad decreases after the elastic deformation of the caliper and friction member has almost recovered. , brake clearance will be ensured even after sudden braking.
When the caliper, etc. undergoes large elastic deformation, the brake pads are thick, and while the piston is supported by the thick brake pads, the elastic deformation of the caliper and friction member is restored, so sudden braking causes The apparent thickness of the brake pad decreases after the larger-than-normal movement of the piston (to be more precise, the larger-than-normal relative movement between the piston and the cylinder) is resolved against the regulating force of the backward limit position regulating means. I will do it. Also,
Since the back plates of the pair of brake pads are constantly pressed against the holding member by the retract spring, the effect of reducing the thickness of the brake pads always appears between the friction member and the friction surface of the disc rotor.
This ensures that the friction member is separated from the brake pad.

Moreover, even if such sufficient brake clearance is generated, no extra brake fluid is required to eliminate this brake clearance during braking, and the operating stroke of the brake pedal does not become large. This is because, during braking, the brake pad becomes thicker by an amount approximately equal to the brake clearance.

Effects of the invention As detailed above, according to the invention, even after large elastic deformation occurs in the caliper cylinder etc. during sudden braking, there is a gap between the friction member of the brake pad and the disc rotor when the brake is released. A certain brake clearance is reliably generated, and the occurrence of dragging is well prevented, and the problems of increased fuel consumption and shortened brake pad life caused by dragging are solved.

Furthermore, there is no need to particularly increase the rigidity of the brake components such as the caliper, and there is no need to increase the operating stroke of the brake pedal, thereby reducing brake operability.

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

In the figure, 1 is a disc rotor that rotates together with wheels (not shown), and is provided with a pair of friction surfaces on both sides. An inner pad 2 and an outer pad 3 are arranged at positions facing both friction surfaces of the rotor 1, and the pair of brake pads 2, 3
A caliper 4 is arranged so as to straddle the.
The caliper 4 is fixed to a non-rotating member at a fixed position, and is provided with an actuator formed of a pair of cylinder parts and pistons 6 and 7 that are slidably fitted to the cylinder parts at positions facing each of the pads 2 and 3. A rubber piston seal 45 (see FIG. 7) is disposed between the pistons 6, 7 and the cylinder portion, and serves both to prevent leakage of brake fluid and to retract the piston. When the brake is applied, brake fluid pressure is supplied into the cylinder section, and when the pair of pistons 6 and 7 are pushed out, the pair of pads 2 and 3 are pressed against both friction surfaces of the rotor 1. Rotation seems to be suppressed.

The inner pad 2 includes a friction member 8 which faces the rotor 1 closely and whose upper side (the side away from the axis of the rotor 1) has an arc shape, and a friction member 8 which is located behind the friction member 8 (the side far from the rotor 1). It is composed of a fixed rectangular back plate 9 and a holding member 11 that holds the back plate 9 further behind it. At a pair of corners on the lower side of the back plate 9 (on the side closer to the axis of the rotor 1), inclined surfaces 12 and 13 are formed which are inclined with respect to the radial direction of the rotor 1. That is,
As the slopes 12 and 13 move away from the center of the back plate 9 to both sides along the plate surface of the rotor 1,
It is formed in the direction away from the axis of the Further, the back surface 14 of the back plate 9 is inclined in the radial direction of the rotor 1. That is, it is an inclined surface that approaches the plate surface of the rotor 1 as it moves away from the axis of the rotor 1.

Front side of holding member 11 (side near rotor 1)
A frame portion 16 that protrudes toward the rotor 1 is formed around the periphery of the rotor 1 , and the back plate 9 is housed in a recess formed by the frame portion 16 . A pair of through holes 17 are provided in both upper shoulders of the frame portion 16, and a support pin 18 (see FIG. 1) attached to the caliper 4 is inserted into the through hole 17. 3 is made to approach the rotor 1 side or to be separated from the rotor 1 using this support pin 18 as a guide.

Support surfaces 19 and 21 that are inclined in the same direction as the inclined surfaces 12 and 13 of the back plate 9 are formed on the inner end surfaces of both corners on the lower side of the frame portion 16, and the back plate 9 is attached to the support surfaces 1
9, 21. support surface 19,
21 is the friction member 8 after the inner pad 2 is extruded.
is brought into contact with the rotor 1, and as a result, the co-rotation torque of the rotor 1 acts on the friction member 8 in the direction of rotation (direction indicated by arrow A in FIG. 2),
This serves to push the back plate 9 upward together with the friction member 8. The inner surfaces 24 and 26 on both sides of the frame 16, which are continuous with the support surfaces 19 and 21, are made to face the side end surfaces 22 and 23 of the back plate 9 at a constant interval, so that the co-rotation torque of the rotor 1 is applied to the back plate 9. It is a torque receiving surface that contacts and receives the side end surfaces 22 and 23 when the torque is applied. Further, the upper inner surface 27 of the frame portion 16 functions as a stopper surface that prevents the back plate 9 and the friction member 8 from rising excessively. A notch is formed in the lower central portion of the frame portion 16, and a leaf spring (return spring) 28 as a biasing means is disposed within this notch. The return spring 28 is screwed to the back plate 9 at its central protruding portion, and its both ends are engaged with the grooves 15 formed in the frame 16 to urge the back plate 9 downward. are doing.

The front side of the holding member 11, that is, the back surface 14 of the back plate 9
A sliding contact surface 29 that is inclined in the same direction as the back surface 14 is formed on the side facing the. The friction member 8 and the back plate 9 are caused by the co-rotation torque of the rotor 1 acting on the friction member 8, and the back plate 9 is connected to the support surface 19,
21 and is pushed upward from the lowered original position by the return spring 28, it is pushed toward the rotor 1. In this embodiment, the support surfaces 19 and 21 function as guide surfaces.

Note that the outer pad 3 is similar to the inner pad 2, so a description thereof will be omitted.

Inner pad 2 and outer pad 3 having such a configuration
As shown in FIG. 1, a pair of retract springs 31 are disposed between the pads 31 and 31 so as to push the pressed pads 2 and 3 back to the retracted position when the brake is applied. ing. The spring 31 has the shape of a wire bent into a dogleg shape, and has engaging portions (see FIG. 4) formed at both ends thereof extending in a direction perpendicular to the plate surface of the back plate 9.
One end of the pair of springs 31 is engaged with an engagement hole 32 provided on both upper shoulders of the back plate 9 of the inner pad 2, and the other end extends beyond the outer circumferential surface of the rotor 1 to the outer pad 3. The pads are engaged with the engagement holes in the back plate, thereby urging the pair of pads 2 and 3 away from the rotor 1.

Next, the operation of the disc brake constructed as described above will be explained. When the brake pedal is depressed and brake fluid is supplied into the cylinder of the caliper 4,
First, the piston 6 is slidably fitted into this cylinder part,
7 is pushed out toward the rotor 1 while causing the piston seal disposed between the piston and the cylinder portion to undergo shear elastic deformation. As a result, the pair of pads 2 and 3 are also pushed out toward the rotor, and
Each friction member is brought into contact with the rotor 1. When the friction member is brought into contact with the rotor 1, the co-rotation torque of the rotor 1 acts on the friction member 8 and its back plate 9 (the outer pad 3 also has a similar effect, so only the inner pad 2 will be explained below). As a result, the back plate 9 is pushed upward against the elastic force of the return spring 28 while sliding the inclined surface 12 against the support surface 19. When the back plate 9 is pushed upward, the back plate 9 is pushed forward (in the direction toward the rotor 1) while elastically deforming the spring 31 by the action of the sliding surface 29 of the holding member 11. , the rotor 1 is brought into even stronger contact.
Then, this reaction force acts on the piston 6, pushing it back into the cylinder part and increasing the hydraulic pressure in the cylinder part, which promotes elastic deformation of the rubber hose and sealing member in the hydraulic circuit. Therefore, an amount of braking fluid approximately symmetrical to the amount of return of the piston 6 is consumed (absorbed). It should be noted that at this stage, the hydraulic pressure in the cylinder section has not become very high, so there is no possibility that an unexpectedly large braking effect will be produced simply by lightly pressing the brake pedal. Padded 2
The support surface 19 is arranged so that when the back plate 9 is pushed up the most, a braking effect that is slightly felt by the driver appears, or a state immediately before such a braking effect appears. The inclination angle of the sliding surface 29 is determined. When the brake pedal is then further depressed, a substantial braking effect is obtained for the first time.

Next, when the brake pedal is released and the brake fluid pressure is released, the pad 2 is separated from the rotor 1 by the urging force of the spring 31. At the same time or prior to this, the upward force due to the co-rotation torque acting on the back plate 9 based on the frictional force between the rotor 1 and the friction member 8 becomes smaller than the biasing force of the return spring 28, and the back plate 9 is pulled downward. Note that which of the separation of the pad 2 from the rotor 1 and the lowering of the back plate 9 occur first depends on how the set load of the return spring 28 is determined.

Furthermore, since the back plate 9 is pressed against the holding member 11 by the biasing force of the spring 31, when the back plate 9 is pulled down, its back surface 14 slides along the sliding surface 29 of the holding member 11. As a result, the back plate 9 is retracted into the recess formed by the frame portion 16 of the holding member 11.

Note that since both ends of the return spring 28 are fixedly attached to the holding member 11, the back plate 9, which has been raised and advanced toward the rotor 1, is held by the spring 3.
1, it also has the effect of separating it from the rotor 1, that is, the effect of pressing the back surface 14 of the back plate 9 against the sliding surface 29 of the holding member 11.

As mentioned above, such a disc brake has a back plate 9.
The relative movement between the piston 6 and the caliper 4 (cylinder part) during braking is reduced by utilizing the relative movement of the brake with respect to the holding member 11, which provides the following advantages. .
In disc brakes, the piston is pushed out and comes into contact with the pads to produce a substantial braking effect, so when the brake pedal is strongly depressed, the fluid pressure increases and the caliper moves the cylinder parts away from each other. While being elastically deformed, the pad 2,
3 is compressively deformed, but since the piston seal disposed between the piston and the cylinder part has a constant allowable amount of elastic deformation,
When the elastic deformation of the caliper or the like becomes particularly large during sudden braking, a shift occurs at the contact surface between the piston and the piston seal, which is moved in the opposite direction to the direction in which the piston protrudes. If the deviation is caused in this way, the piston will not return to its original position when the brake fluid pressure is removed, but will be in a state where it is extra protruded from the cylinder toward the rotor by the amount of the deviation. Become. This means that the clearance between the rotor and the pads decreases by that amount, and if this amount of deviation is larger than the initial clearance, the piston will always press the pads against the rotor, causing the pads to This will cause a drag. However, in the above disc brake, the piston is temporarily pushed back into the cylinder part as the friction member 8 and back plate 9 rise, and this reduces the amount of braking fluid consumed by the elastic deformation of the seal member, rubber hose, etc. Since the brake pedal is replenished, it is possible to increase the initial clearance while maintaining the brake pedal stroke at the same size as before. Therefore, it is easy to make the initial clearance larger than the amount of elastic deformation of the caliper or pad, and the occurrence of dragging due to the above-mentioned causes can be reliably prevented.

Moreover, in the pad 2, the back surface of the holding member 11 is
The rotor 1 is moved away from the rotor 1 by the spring 31 until it comes into contact with the tip end surface of the piston that is returned to its original position.
A predetermined amount of clearance is reliably created between the friction member 2 and the friction member 2.

Furthermore, when the clearance between the pads and the rotor is extremely small, if vibrations from the vehicle are transmitted to the pads while the vehicle is running, there is a risk that the pads will move toward the rotor and cause the above-mentioned dragging. In the disc brake of this configuration, a predetermined amount of clearance is secured between the pad 2 and the rotor 1, and the pad 2 is always biased in the direction away from the rotor 1, so even if the vibration of the vehicle occurs, the rotor 1 Therefore, the above-mentioned dragging is reliably prevented, resulting in reduced fuel consumption and improved pad life.

Next, another embodiment of the present invention will be described based on FIGS. 5 and 6. In this embodiment, the back surface 35 of the back plate 33 is inclined in a direction perpendicular to the radial direction of the rotor 1. That is, the back surface 35 is
It is an inclined surface that approaches the rotor 1 as it advances in the rotation direction of the rotor 1 (direction of arrow B in FIG. 5), and the front surface 36 of the holding member 34 is a sliding surface that is inclined in the same direction. rotor 1 to member 37
When the back plate 33 is guided by the lower inner surface of the frame of the holding member 34 and moved in the direction shown by arrow B, the friction member 37 is moved toward the rotor 1. It seems like it's being pushed out.

The lower inner surface is a plane extending in a direction perpendicular to the radial direction of the rotor 1, and functions as a guide surface for guiding the movement of the back plate 33.

A recess 38 is formed on one side of the holding member 34 in the same direction, and a protrusion 3 provided on the back plate 33
9 is inserted into this recess 38. A return spring 41 as a biasing means is attached between the side surface of the protrusion and the inner surface of the frame portion of the back plate 33, and the return spring 41 is attached as a biasing means to connect the back plate 33 and the friction member 37 as shown by arrow B on the inner surface of the frame portion of the holding member 34. It is biased toward the original position where it comes into contact with the surface opposite to the surface facing the rotor in the rotating direction. Engagement holes 42 similar to those in the embodiment described above are provided in both upper shoulders of the back plate 33, and the springs 31 are inserted into the engagement holes 42.
are engaged so that the biasing force is applied to the back plate 33.

In a disc brake using a pad with such a configuration, the back plate 33 is moved in the rotational direction of the rotor 1 as the friction member 37 comes into contact with the rotor 1, thereby pushing the friction member 37 toward the rotor 1. and is brought into even stronger contact with the rotor 1.
Also, when the brake is released, the back plate 33 is operated by the return spring 41 and the spring 31, as in the previous embodiment.
is pulled back to the holding member 34 and the pad itself is separated from the rotor 1, creating a clearance between the friction member 37 and the rotor 1.

As shown in the above embodiment, the present invention is not limited to a type with a pair of pistons, but can also be applied to a type with two pairs of pistons facing each other, and can also be applied to a cylinder-opposed type with a fixed caliper. It is applicable not only to the type but also to the caliper floating type disc brake.

[Brief explanation of the drawing]

Figure 1 is a plan view of a disc brake constructed according to the present invention, Figure 2 is a front view of the pad in Figure 1, Figure 3 is a cross-sectional view of the pad in Figure 2, and Figure 4 is the figure in Figure 1. FIG. 5 is a front view of a pad used in another embodiment of the present invention, FIG. 6 is a cross-sectional view of FIG. 5, and FIG.
Figures A and B are partial cross-sectional views of the disc brake shown in Figure 1, respectively. 1: Disc rotor, 2: Inner pad, 3:
Outer pad, 4: Caliper, 6, 7: Piston, 8, 37: Friction member, 9, 33: Back plate, 1
1, 34: holding member, 12, 13: inclined surface, 1
4, 35: Back, 19, 22: Support surface, 29, 3
6: Sliding surface, 31: Retract spring, 3
2, 42: Engagement hole.

Claims (1)

[Claims for Utility Model Registration] (1) A rotating disc rotor having friction surfaces on both sides; a pair of brake pads disposed on both sides of the disc rotor facing the friction surfaces; a caliper that is provided with an actuator that operates and is disposed so as to straddle the disc rotor and the pair of brake pads, and that comes into contact with the back surface of each brake pad to press them against the disc rotor; and a caliper that is disposed between the pair of brake pads. a retract spring whose both ends engage each brake pad and apply a biasing force to each brake pad in a direction away from the disc rotor; and a limit to which the pair of brake pads can be retracted by the biasing force of the retract spring. At the same time, in a disc brake equipped with a backward limit position regulating means for moving the backward limit position of the brake pad closer to the disc rotor when the brake pads are worn, each of the pair of brake pads is arranged to face the friction surface of the disc rotor. a friction member that
A back plate fixed behind the friction member; and further behind the back plate, the back plate is held movably in a direction substantially parallel to the friction surface of the disc rotor, and the movement of the back plate is guided. a holding member having a guide surface, the friction member receiving the friction surface of the disk rotor when the friction member contacts the friction surface of the disc rotor; The friction member and the back plate are inclined with respect to the friction surface of the disc rotor in a direction that pushes the friction member and the back plate toward the disc rotor as the back plate moves from the original position while being guided by the guide surface based on rotational torque. and a biasing means for biasing the back plate toward the original position, and both ends of the retract spring are engaged with each back plate of the pair of brake pads so that the back plate of each back plate is moved toward the original position. A disc brake characterized in that the holding member is pressed against a sliding surface of the holding member and urged in a direction away from the disc rotor. (2) The guide surface is a plane inclined with respect to the radial direction of the disc rotor, and the back surface of the back plate and the sliding surface of the holding member are inclined in the radial direction of the disc rotor. A disc brake according to claim 1 of the utility model registration claim. (3) The guide surface is a plane extending in a direction perpendicular to the radial direction of the disc rotor, and the back surface of the back plate and the sliding surface of the holding member are arranged in a direction perpendicular to the radial direction of the disc rotor. The disc brake according to claim 1 of the utility model registration claim, which is inclined.