JP5370684B2 - Disc brake device - Google Patents

Description

  The present invention relates to a disc brake device in which a disc rotor that rotates integrally with a wheel is clamped by a friction pad provided on a caliper so that a braking force is applied to the wheel via the disc rotor by its frictional resistance.

  In a general caliper floating type disc brake device, a caliper arranged so as to straddle the disc rotor is supported by a mounting bracket. The caliper is provided with a pair of slide pins, and the mounting bracket is provided with a fitting hole for slidably fitting the pair of slide pins. Thus, the caliper can move in the direction of the rotation axis of the wheel by sliding the slide pin with respect to the fitting hole. Further, an inner pad (friction pad) is movably supported on one side of the caliper, and an outer pad (friction pad) is fixed on the other side. Further, the caliper is provided with a piston and a cylinder for pressing (crimping) the inner pad against the disk rotor on one side.

  In such a caliper floating type disc brake device, when the driver depresses the brake pedal, the piston supported by the cylinder advances in accordance with the depression force, and the inner pad is pressed (crimped) against the disc rotor. The caliper moves in the direction of the rotational axis of the wheel by the reaction force of the piston moving forward, and presses (compresses) the outer pad against the disk rotor. Thus, the inner pad and the outer pad can sandwich the disc rotor, and a braking force can be applied to the wheel via the disc rotor that rotates integrally with the wheel.

  By the way, the piston provided in the caliper is movably supported by a cylinder formed in the caliper and held fluid-tight by a piston seal, and hydraulic fluid (brake fluid) is formed in a hydraulic chamber formed in the cylinder during braking. ), The piston moves forward while deforming the piston seal, and when the hydraulic pressure is released from the hydraulic chamber (when the pressure is released), the piston moves backward toward the hydraulic chamber due to the restoring force of the deformed piston seal. Is configured to do. However, for example, when the driver's brake pedal depression force is excessive, the piston is pushed toward the disc rotor more than a predetermined amount as the hydraulic pressure in the hydraulic chamber increases, and there is a relative movement between the piston and the piston seal. In some cases, the piston cannot be fully retracted due to the restoring force of the piston seal. In this case, there is a possibility that a phenomenon in which the inner pad or the outer pad keeps in contact with the disk rotor, that is, a so-called drag phenomenon occurs. In addition, when the drag phenomenon occurs in this way, there is a possibility that a so-called knockback occurs in which the inner pad or the outer pad is repelled by the rotating disk rotor and pushes back the piston.

  In order to solve this problem, for example, a disc brake device disclosed in Patent Document 1 below and a disc brake caliper disclosed in Patent Document 2 below are known.

  The disc brake device disclosed in the following Patent Document 1 forms an annular ring mounting groove in an inner hole of a cylinder and forms a chamfered portion on the pad side at an opening edge on the pad side of the ring mounting groove. In addition, a retraction ring that seals the piston and cylinder and returns the piston when the pressure is released after braking is assembled. In addition, an annular recess that opens toward the pad side end wall is formed in the pad side end wall of the ring mounting groove, and the ring of the retraction ring assembled in the ring mounting groove is formed in the annular recess. A deformation-accepting ring made of a compressible material that allows entry deformation into the recess is assembled. As a result, the hydraulic pressure at which the amount of flexure of the pad and cylinder, which increases as the hydraulic pressure increases, becomes larger than the amount of piston retracted by the retraction ring can be set to a higher value. Drag can be reduced to the usage environment that becomes pressure.

  The disc brake caliper disclosed in Patent Document 2 below is provided with a piston seal that frictionally engages with the outer peripheral surface of the piston by a retainer in a large-diameter hole formed in the caliper body, and the retainer is moved in the retracting direction of the piston. A disc spring is provided for biasing. As a result, when the brake fluid pressure is low, the retainer is prevented from advancing by the preload of the disc spring, and the piston seal is elastically deformed into the chamfered portion by the advance of the piston, and the piston is restored by the restoring force of the piston seal when the pressure is released. Retraction can be ensured to prevent the drag phenomenon. On the other hand, when the brake fluid pressure is high, the retainer and piston seal overcome the preload of the disc spring and move forward, so there is no sliding (relative movement) between the piston and piston seal. Retraction can prevent the occurrence of drag phenomenon. Also, when the brake pad is worn, the piston seal is elastically deformed to the allowable limit, and then the piston is allowed to move forward by sliding (relative movement) between the piston and the piston seal, thereby correcting the clearance between the brake pad and the disc rotor. can do.

JP 7-253128 A Japanese Unexamined Patent Publication No. 5-65929

  By the way, in the conventional disc brake device described above, the clearance between the piston and the friction pad (disc rotor) may fluctuate due to pressure history, knockback, pad wear, and the like. The position of the traction ring is not stable, and there is a possibility that the piston cannot be retracted stably. For this reason, even if a drag phenomenon occurs, it is difficult to cancel the drag phenomenon, and even when there is a clearance greater than a specified value between the piston and the pad (disk rotor), it can be corrected to the specified value. It can be difficult.

  In the conventional disc brake caliper, when the brake pad is worn and the brake fluid pressure is high, a relative movement occurs between the piston and the retraction ring, and the piston advances more than the compression amount of the disc spring. There is a possibility that the piston cannot be retracted properly and a pad drag phenomenon may occur.

  That is, in the conventional disc brake device and disc brake caliper, the piston is returned by the piston seal. However, there is a possibility that the piston cannot be sufficiently returned only by the restoring force of the piston seal, and as a result, a pad drag phenomenon may occur.

  The present invention has been made to cope with the above-described problems, and an object of the present invention is to provide a disc brake device that appropriately returns a piston to suppress the occurrence of a pad drag phenomenon.

In order to achieve the above object, the present invention is characterized in that a disk rotor that rotates integrally with a wheel around a rotation axis and a friction pad that faces the friction surface of the disk rotor are increased as the brake fluid pressure increases. The caliper having a piston that presses against the friction surface and a cylinder that supports the piston so as to be able to advance and retreat, and the caliper is housed in the cylinder of the caliper so as to seal the piston and advance to press the friction pad. A disc brake device including a seal mechanism for retracting a piston in accordance with a decrease in the brake fluid pressure; and seal means for sealing the seal mechanism between an inner peripheral surface of the cylinder and an outer peripheral surface of the piston. A rigid outer slider that slides against the inner peripheral surface of the cylinder following the piston, and the outer slider and the front A high-elasticity inner slider that is provided between the piston and follows the piston integrally with the outer slider; and as the brake fluid pressure increases, the piston, the outer slider, and the inner slider The following means for allowing relative movement between the piston, the outer slider and the inner slider when a predetermined load is applied, and compression by the movement of the outer slider of the following means following the advance of the piston. And a restoring force applying means for applying a restoring force against the compression to the outer slider of the tracking means as the brake fluid pressure decreases, and the tracking means increases as the brake fluid pressure increases. When the outer slider and the inner slider advance integrally following the advance of the piston, When advance of the piston is inhibited, allowing forward with respect to the piston is stopped in the outer slider and the inner slider by the predetermined load the preset by the brake fluid pressure acts, the brake fluid pressure As the force decreases, the restoring force applied to the outer slider by the restoring force applying means is transmitted to the piston via the inner slider so that the piston, the outer slider and the inner slider are integrated. To retreat to. In this case, the sealing means, the follow-up means, and the restoring force applying means constituting the sealing mechanism may be accommodated in, for example, a sealing groove formed in the cylinder of the caliper. In this case, the sealing means, the follow-up means, and the restoring force applying means may be disposed in the seal groove in the forward direction of the piston. Further, the predetermined load set in advance may be set in advance, for example, depending on the magnitude of the frictional force between the inner peripheral surface of the inner slider and the outer peripheral surface of the piston.

Also, the follow-up means, the yo Ri Specifically, if example embodiment, when being advanced integrally the outer slider and the inner slider with an increase of the brake fluid pressure to follow the forward movement of the piston When the piston presses the friction pad and the friction pad presses against the friction surface of the disk rotor, and the forward movement of the piston is inhibited, the outer slider and the inner slider are allowed to advance.

  Further, the magnitude of the frictional force between the inner peripheral surface of the cylinder and the outer peripheral surface of the outer slider of the follower means is the friction between the inner peripheral surface of the inner slider of the follower means and the outer peripheral surface of the piston. It should be smaller than the magnitude of the force. Further, the contact surface between the outer slider and the inner slider of the follow-up means may be formed in an uneven shape that fits together.

  Further, the inner slider of the sealing means and the follower means, or the inner slider of the follower means and the restoring force applying means may be integrally formed. In this case, it is preferable to provide a groove formed in the circumferential direction with respect to the inner peripheral surface that contacts the outer peripheral surface of the piston of the integrally formed inner slider.

  According to these, the sealing mechanism is composed of sealing means, following means (inner slider and outer slider) and restoring force applying means, and the sealing mechanism has a sealing function, a following function (stroke absorbing function), and a returning function (retract function). Can be independently provided. And the sealing mechanism which has these functions can be accommodated in the caliper seal formed also in the conventional disc brake device.

  Further, in the seal mechanism, the following means (inner slider and outer slider) can follow the advance of the piston. The follow-up means can move forward by compressing the restoring force applying means. Further, in a situation where the movement of the piston or the follower means (inner slider and outer slider) is hindered when the brake fluid pressure is increasing, the predetermined load, more specifically, the friction between the piston and the inner slider. When a load greater than the force is applied, the piston or the following means (inner slider and outer slider) whose movement is not hindered can move forward with relative movement. Even in such a relative movement, the follower (the inner slider and the outer slider) can compress the restoring force applying unit.

  As a result, the compressed restoring force applying means can apply a restoring force to the following means (inner slider and outer slider), so that the following means (particularly the inner slider that moves integrally with the outer slider) By this restoring force, the piston advanced to press the friction pad can be integrally returned by an appropriate amount. Therefore, the distance (clearance) between the piston and the friction pad (disk rotor) can be appropriately secured, and as a result, the occurrence of the friction pad drag phenomenon can be suppressed and a stable brake feeling can be obtained. it can.

  Also, the inner slider of the sealing means and the follower means, or the inner slider of the follower means and the restoring force applying means can be integrally formed. Thereby, for example, the number of parts accommodated in the caliper seal groove can be significantly reduced, and as a result, the assemblability can be greatly improved.

1 is a schematic view of a disc brake device common to embodiments of the present invention. FIG. 2 is an enlarged schematic view illustrating a sealing mechanism according to the first embodiment of the present invention. It is a figure for demonstrating the case where the piston of FIG. 2, an inner slider, and an outer slider move forward without relative movement. It is a figure for demonstrating the case where the piston of FIG. 2 moves relatively with respect to an inner side slider and an outer side slider, and advances. It is a graph for demonstrating the relationship of the stroke amount of the piston with respect to brake fluid pressure. It is a figure for demonstrating the case where the inner side slider and outer side slider of FIG. 2 move relatively with respect to a piston, and advance. It is the schematic shown expanded in order to demonstrate the sealing mechanism which concerns on the modification of 1st Embodiment of this invention. It is a figure for demonstrating the action | operation of the seal mechanism of FIG. It is a schematic diagram expanding and showing for explaining a seal mechanism concerning a 2nd embodiment of the present invention. It is a figure for demonstrating the action | operation of the seal mechanism of FIG. FIG. 9 is an enlarged schematic view illustrating a sealing mechanism according to a modification of the second embodiment of the present invention. It is a figure for demonstrating the action | operation of the seal mechanism of FIG.

a. First Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 schematically shows a caliper floating disc brake device common to the embodiments of the present invention.

  This disc brake device is provided along a rotation axis direction of the disc rotor 11 by a disc rotor 11 that rotates around a rotation axis of an axle integrally with a wheel (not shown), and a mounting bracket (not shown) fixed to the vehicle body side. The caliper 12 is movably supported.

  The caliper 12 has a substantially U-shaped cross section so as to straddle the disc rotor 11, and a cylinder portion 13 to which brake fluid is supplied according to a brake operation by the driver, and the cylinder portion 13 and the disc rotor 11 are connected to each other. It is comprised from the nail | claw part 14 arrange | positioned in the position which opposes via, and the connection part 15 which connects the cylinder part 13 and the nail | claw part 14. As shown in FIG. The cylinder portion 13 includes a seal mechanism 20 described later, and supports the piston 16 through the seal mechanism 20 so that the piston 16 can advance and retract in a liquid-tight manner.

  The caliper 12 is assembled with a pair of friction pads 17 and 18 that face the friction surfaces on both sides of the disk rotor 11. The friction pads 17 and 18 are respectively disposed on the cylinder part 13 side and the claw part 14 side of the caliper 12. In the following description, the friction pad 17 disposed on the cylinder part 13 side of the caliper 12 and pressed by the piston 16 is referred to as an inner pad 17, and the friction pad 18 disposed on the claw part 14 side is referred to as an outer pad 18. . Although detailed description is omitted, the inner pad 17 and the outer pad 18 are configured such that the base end portions of the friction materials 17a and 18a are fixed to the back plates 17b and 18b.

  As specifically shown in FIG. 2, the seal mechanism 20 in the first embodiment is accommodated in a caliper seal groove 13 a having a substantially rectangular cross section formed in an annular shape on the inner peripheral surface of the cylinder portion 13. The sealing mechanism 20 seals the brake fluid supplied to the cylinder portion 13, a follow-up function (stroke absorbing function) that follows the piston 16 when the brake fluid is pressurized, and the piston 16 when the brake fluid is depressurized. A pull back function (retract function) is demonstrated. For this reason, the seal mechanism 20 includes a seal member 21, an inner slider 22 provided on the outer peripheral surface of the piston 16, and an outer slider provided between the inner peripheral wall surface 13a1 of the caliper seal groove 13a and the inner slider 22. 23 and a return member 24.

  The sealing member 21 as a sealing means is mainly for exhibiting a sealing function for preventing leakage of brake fluid supplied to the cylinder portion 13, and the inner peripheral wall surface 13 a 1 of the caliper seal groove 13 a and the piston 16 It seals between the outer peripheral surfaces. For this reason, the seal member 21 is formed from an elastic material (for example, a rubber material), and a fastening allowance (compression rate) set in advance between the inner peripheral wall surface 13a1 of the caliper seal groove 13a and the outer peripheral surface of the piston 16 is used. ) And is accommodated in the caliper seal groove 13a. As a result, the seal member 21 defines a hydraulic pressure chamber 13b in the cylinder portion 13 that is filled with the brake fluid whose pressure has been adjusted. As the seal member 21, for example, an O-ring whose cross section is O-shaped as shown in FIG. 2 or a D-ring whose cross-section not shown is D-shaped can be adopted.

  The inner slider 22 as the following means is mainly for exhibiting a following function, and follows the movement of the piston 16 in the front-rear direction. For this reason, the inner slider 22 is formed in a ring shape from a highly elastic and high friction material (for example, a rubber material), and is set in advance to the outer peripheral surface of the piston 16, in other words, preset. It is accommodated in the caliper seal groove 13a so as to have a tight force. The shape of the inner slider 22 is such that the filling rate between the outer slider 23 and the piston 16 is small in order to follow the movement of the piston 16 in the front-rear direction, in other words, in order to reduce the relative displacement. For example, a rectangular ring having a substantially rectangular cross section as shown in FIG. 2 or a D ring having a D cross section not shown in the figure can be adopted.

  The outer slider 23 as the follower is also mainly for exhibiting a follower function. The inner slider 22 is held in the caliper seal groove 13a from the outer peripheral side, and slides on the inner peripheral wall surface 13a1 of the caliper seal groove 13a. It moves (slides) integrally with the inner slider 22 by moving. For this reason, the outer slider 23 has a high rigidity and low friction material (for example, Teflon) so that it can easily slide with respect to the inner peripheral wall surface 13a1 of the caliper seal groove 13a without being deformed as the inner slider 22 slides. (Registered trademark)) and is slidably accommodated together with the inner slider 22 in the caliper seal groove 13a. A holding groove 23a for holding the inner slider 22 is formed on the inner peripheral surface of the outer slider 23, and the inner slider 22 is assembled integrally. The outer slider 23 is preferably formed in a continuous ring shape, but a discontinuous portion may exist in part.

  The return member 24 as a restoring force applying means is mainly for exerting a return function, and moves the inner slider 22 and the outer slider 23 that slide in the caliper seal groove 13a to the rear ( It is to be returned in the direction of the seal member 21). For this reason, the return member 24 is formed into a ring shape from a highly elastic material (for example, rubber material), and its cross-sectional shape increases the elastic force against the elastic deformation caused by the sliding of the inner slider 22 and the outer slider 23, in other words. For example, it is formed into a shape that protrudes toward the outer slider 23 (such as an O shape shown in FIG. 2 or a D shape not shown) so as to increase the restoring force. The return member 24 is accommodated in the caliper seal groove 13a so that the pressing force against the outer peripheral surface of the piston 16 is extremely small.

  In the sealing mechanism 20 configured as described above, the inner slider 22 formed from a high friction material contacts the outer peripheral surface of the piston 16 with a predetermined pressing force, and the outer slider 23 formed from a low friction material is disposed on the inner side. The slider 22 is held integrally. Thereby, when the piston 16 moves in the front-rear direction, the inner slider 22 follows the piston 16 due to friction and slides in the caliper seal groove 13a. Accordingly, the outer slider 23 slides in the caliper seal groove 13 a integrally with the slide of the inner slider 22. At this time, since the outer slider 23 is formed from a low friction material, the outer slider 23 slides smoothly without causing a large frictional resistance against the inner peripheral wall surface 13a1 of the caliper seal groove 13a. Therefore, the inner slider 22 and the outer slider 23 follow well with respect to the movement of the piston 16 in the front-rear direction.

  Further, the inner slider 22 and the outer slider 23 are disposed between the seal member 21 having elasticity and the return member 24 having elasticity higher than that of the seal member 21 in the caliper seal groove 13a. That is, as shown in FIG. 2, the seal member 21 is disposed so as to contact the inner slider 22 and the outer slider 23 (more specifically, the outer slider 23) and the hydraulic chamber side wall surface 13a2 forming the caliper seal groove 13a. The return member 24 is disposed so as to contact the inner slider 22 and the outer slider 23 (more specifically, the outer slider 23) and the opening side wall surface 13a3 forming the caliper seal groove 13a. In the following description, as shown in FIG. 2, the inner slider 22 and the sealing member 21 and the return member 24 are in contact with the outer slider 23, the hydraulic chamber side wall surface 13a2, and the opening side wall surface 13a3. The slide position of the outer slider 23 is referred to as the original position.

  For this reason, when the inner slider 22 and the outer slider 23 slide forward from the original position following the advance of the piston 16 in the direction in which the inner pad 17 is pressed, the return member 24 moves between the outer slider 23 and the opening side wall surface 13a3. Compressed between them and elastically deformed. Thereby, the return member 24 can apply an elastic force (restoring force) according to the sliding amount of the outer slider 23, in other words, the compression amount, to the outer slider 23. Here, when the inner slider 22 and the outer slider 23 slide following the advance of the piston 16, the sliding amount from the original position of the inner slider 22 and the outer slider 23 is regulated by the maximum elastic deformation amount of the return member 24. The That is, the sliding amount of the inner slider 22 and the outer slider 23 regulated by the maximum elastic deformation amount of the return member 24 corresponds to the return amount (retract amount) for returning the piston 16. The restoring force applied to the outer slider 23 from the return member 24 is transmitted to the piston 16 via the inner slider 22 held by the outer slider 23, so that the piston 16 is moved away from the inner pad 17. Acts as a return force to retract.

  On the other hand, since the outer slider 23 is formed of a low friction material, the inner slider 22 and the outer slider 23 quickly slide toward the original position, that is, toward the seal member 21 by this return force. Further, the outer slider 23 is moved in the original position, that is, the seal member, also by an external force input to the piston 16 through the inner pad 17 due to the displacement (inclination) of the disc rotor 11 in the rotation axis direction when the vehicle turns. There is a case of sliding toward 21 directions.

  Here, since the seal member 21 is formed from an elastic material, when the seal member 21 is compressed and elastically deformed between the outer slider 23 and the hydraulic chamber side wall surface 13a2, an elastic force (restoring force) is applied to the outer slider 23. Can be granted. Therefore, the inner slider 22 and the outer slider 23 are returned to their original positions by the elastic force (restoring force) applied from the return member 24 and the elastic force (restoring force) applied from the seal member 21.

  Next, the operation of the disc brake device according to the first embodiment configured as described above will be described. In the disc brake device, when the brake fluid is supplied to the cylinder portion 13 of the caliper 12 and the pressure in the hydraulic pressure chamber 13b of the cylinder portion 13 is increased, the piston 16 advances toward the disc rotor 11 and the piston 16 moves forward. 16 presses the inner pad 17 and presses against the friction surface of the disk rotor 11. At this time, the caliper 12 moves in a direction opposite to that of the piston 16 due to the reaction caused by the forward movement of the piston 16, and presses the outer pad 18 assembled to the claw portion 14 against the friction surface of the disc rotor 11. As a result, a frictional resistance force is generated between the inner pad 17 and the outer pad 18 and the rotating disk rotor 11, and a braking force can be applied to the disk rotor 11, that is, the wheels.

  On the other hand, when the brake fluid is discharged from the cylinder portion 13 of the caliper 12 and the pressure in the hydraulic chamber 13b of the cylinder portion 13 is reduced, the piston 16 moves backward in the direction away from the disk rotor 11 and the inner pad. 17 is separated from the friction surface of the disk rotor 11. At this time, the caliper 12 moves in the direction opposite to the piston 16 due to the reaction caused by the retraction of the piston 16, and the outer pad 18 assembled to the claw portion 14 is separated from the friction surface of the disk rotor 11.

  By the way, with respect to such forward and backward movement of the piston 16, the seal mechanism 20 of the caliper 12 corresponds to the magnitude of the pressure in the hydraulic chamber 13b and the wear state of the inner pad 17 (and the outer pad 18). Follow the piston 16 and return the piston 16. Hereinafter, the operation of the seal mechanism 20 will be described in detail.

  First, the case where the pressure in the hydraulic chamber 13b during pressurization is low will be described. In this case, when the piston 16 moves forward in accordance with the increase in the pressure in the hydraulic pressure chamber 13b, the inner slider 22 moves relative to the forward movement of the piston 16 due to friction caused by a predetermined tightening force, as shown in FIG. Follow up without producing. As a result, the inner slider 22 and the outer slider 23 integrally slide in the caliper seal groove 13a toward the return member 24. And the outer side slider 23 compresses the return member 24 with the opening side wall surface 13a3. At this time, since the pressure in the hydraulic chamber 13 b is low, the return member 24 is elastically deformed to an elastic deformation amount that is less than the maximum elastic deformation amount, and a restoring force corresponding to the elastic deformation amount is applied to the outer slider 23. Give. In this state, when the pressure in the hydraulic chamber 13 b is removed, the inner slider 22 and the outer slider 23 are returned to their original positions by the restoring force of the return member 24 and the inner slider 22 is restored to the piston 16 by the restoring force. To communicate. As a result, the piston 16 is returned by a retract amount corresponding to the elastic deformation amount of the return member 24.

  Next, when the pressure in the hydraulic chamber 13b during pressurization is high, as shown in FIG. 3, the inner slider 22 follows the forward movement of the piston 16 without causing relative movement, The slider 23 elastically deforms the return member 24 until the maximum elastic deformation amount is reached. In this state, when the pressure in the hydraulic chamber 13 b is removed, the inner slider 22 and the outer slider 23 are returned to their original positions by the restoring force of the return member 24 and the inner slider 22 is restored to the piston 16 by the restoring force. To communicate. Thereby, the piston 16 is returned by a retract amount corresponding to the maximum elastic deformation amount of the return member 24.

  Further, when the pressure in the hydraulic chamber 13b during pressurization is excessive, for example, a back plate 17a forming the inner pad 17 or a spacer (shim plate) provided between the end of the piston 16 and the back plate 17a. ) Or the cylinder portion 13 or the like, the amount of advancement of the piston 16 increases beyond a predetermined level. In this case, in a situation where the return member 24 is elastically deformed to the maximum elastic deformation amount, the inner slider 22 and the outer slider 23 cannot slide in the caliper seal groove 13a following the advance of the piston 16. Therefore, in this case, as shown in FIG. 4, the forward force (load) for moving the piston 16 forward by the brake hydraulic pressure is greater than the frictional force (that is, the predetermined load) between the inner slider 22 and the piston 16. If it becomes larger, the advancing piston 16, the inner slider 22 and the outer slider 23 move relative to each other. However, in this state, when the pressure in the hydraulic chamber 13 b is removed, the inner slider 22 and the outer slider 23 are returned to their original positions by the restoring force of the return member 24, and the inner slider 22 is against the piston 16. Transmits restoring force. Thereby, the piston 16 is returned by a retract amount corresponding to the maximum elastic deformation amount of the return member 24.

  Thus, the seal mechanism 20 can return the piston 16 by a predetermined retract amount in accordance with the pressure in the hydraulic chamber 13b. Here, the pressure in the hydraulic chamber 13b of the cylinder part 13, that is, the advance amount of the piston 16 with respect to the brake hydraulic pressure will be described with reference to FIG. As shown by a solid line in FIG. 5, when the advance amount of the piston increases with an increase in the brake fluid pressure, a conventional disc brake device that does not include the seal mechanism 20 is indicated by a one-dot chain line in FIG. As described above, the piston retract amount (return amount) due to the seal retract increases at the initial time and exceeds the piston advance amount. However, since the relative movement between the piston seal and the piston occurs at an early stage, the subsequent retract amount (return amount) does not increase and falls below the advance amount of the piston.

  On the other hand, in the disc brake device of this embodiment provided with the seal mechanism 20, the inner slider 22 and the outer slider 23 follow the advance amount of the piston 16 until the return member 24 is elastically deformed to the maximum elastic deformation amount. And can slide. For this reason, as shown by a broken line in FIG. 5, the retract amount (return amount) of the piston 16 by the seal mechanism 20 continuously increases from the initial time, and exceeds the advance amount of the piston 16 in the entire region. . Therefore, since the piston 16 is returned by a predetermined retract amount depending on the pressure over the entire hydraulic pressure region, the occurrence of the drag phenomenon of the inner pad 17 and the outer pad 18 can be suppressed, and a stable brake fee can be obtained. You can get a ring.

  Next, an operation in which the seal mechanism 20 follows the piston 16 and returns the piston 16 in accordance with the wear state of the inner pad 17 (and the outer pad 18) will be described. First, the case where the wear of the inner pad 17 is large will be described. When the wear of the inner pad 17 (more specifically, the wear of the friction material 17a) is large, the distance (clearance) between the inner pad 17 and the outer pad 18 and the disk rotor 11 becomes large. In this case, in order to press the inner pad 17 against the friction surface of the disk rotor 11, the advance amount of the piston 16 that advances according to the pressure in the hydraulic chamber 13 b of the cylinder portion 13 increases.

  For this reason, in the seal mechanism 20, when the piston 16 moves forward in accordance with an increase in the pressure in the hydraulic chamber 13 b, the inner slider 22 and the outer slider 23 move relative to the piston 16 as described above. The caliper seal groove 13a is slid toward the return member 24. The outer slider 23 elastically deforms the return member 24 with the opening side wall surface 13a3 until, for example, the maximum elastic deformation amount is reached. In this state, if the piston 16 has not yet pressed the inner pad 17, the piston 16 further moves forward, so that the inner slider 22 and the outer slider 23 cannot slide following the advance of the piston 16. That is, in this case, as shown in FIG. 4, the forward force (load) for moving the piston 16 forward by the brake hydraulic pressure is the frictional force (that is, the predetermined load) between the inner slider 22 and the piston 16. The piston 16 and the inner slider 22 and the outer slider 23 move relative to each other, and the piston 16 presses the inner pad 17 by advancing with this relative movement, so that the piston 16 and the friction surface of the disk rotor 11 are not moved. Generate frictional resistance.

  When the pressure in the hydraulic chamber 13b is released, the inner slider 22, the outer slider 23, and the piston 16 are integrated by the elastic force (restoring force) of the return member 24 that is elastically deformed to the maximum elastic deformation amount. And retracts by a retract amount corresponding to the maximum elastic deformation amount. As a result, the inner pad 17 (and the outer pad 18) is returned to a position having a predetermined clearance with the disc rotor 11, so that the drag phenomenon of the inner pad 17 and the outer pad 18 can be suppressed and stable. Brake feeling can be obtained.

  On the other hand, when the worn inner pad 17 (and outer pad 18) is replaced with a new inner pad 17 (and outer pad 18), for example, the distance between the inner pad 17 and the disk rotor 11 ( (Clearance) decreases. In this case, in order to press the inner pad 17 against the friction surface of the disk rotor 11, the advance amount of the piston 16 that advances according to the pressure in the hydraulic chamber 13 b of the cylinder portion 13 decreases.

  For this reason, in the seal mechanism 20, when the piston 16 moves forward in accordance with an increase in the pressure in the hydraulic chamber 13 b, the inner slider 22 and the outer slider 23 move relative to the piston 16 as described above. The caliper seal groove 13a is slid in the direction toward the return member 24 without following the above. Then, before the return member 24 is elastically deformed to the maximum elastic deformation amount by the sliding of the outer slider 23, when the piston 16 presses the inner pad 17 and presses against the disk rotor 11, the piston 16 stops. In this way, when the pressure in the hydraulic chamber 13b is maintained at a high level in a state where the piston 16 stops moving forward, as shown in FIG. 6, the seal member 21 returns the outer slider 23 by the brake hydraulic pressure. Press in 24 directions. At this time, the inner slider 22 held by the outer slider 23 slides with the outer slider 23 against the frictional force with the piston 16. That is, in this state, the forward force (load) for advancing the outer slider 23 and the inner slider 22 via the seal member 21 by the brake fluid pressure is a friction force between the inner slider 22 and the piston 16 (that is, When it becomes larger than the predetermined load), the inner slider 22 and the outer slider 23 move relative to the piston 16, and the outer slider 23 further elastically deforms the return member 24 to the maximum elastic deformation amount, for example.

  When the pressure in the hydraulic chamber 13b is released, the seal member 21, the inner slider 22, the outer slider 23, and the piston 16 are integrally formed by the elastic force (restoring force) of the elastically deformed return member 24. Retract by the retract amount corresponding to the maximum elastic deformation amount. As a result, the inner pad 17 and the outer pad 18 are returned to a position having a predetermined clearance with the disk rotor 11, so that the drag phenomenon of the inner pad 17 and the outer pad 18 can be suppressed, and a stable brake can be achieved. Feeling can be obtained.

  As can be understood from the above description, according to the disc brake device of the first embodiment, the seal mechanism 20 includes the seal member 21, the inner slider 22, the outer slider 23, and the return member 24. A seal function, a follow-up function (stroke absorption function), and a return function (retract function) can be provided independently. And the sealing mechanism 20 which has these functions can be accommodated in the caliper seal 13a formed also in the conventional disc brake device. Thereby, in order to accommodate the seal mechanism 20, it is possible to eliminate the need for additional work on the caliper 12 (specifically, the inner peripheral surface of the cylinder portion 13).

  Further, in the seal mechanism 20, the inner slider 22 and the outer slider 23 as the follower can follow the forward movement of the piston 16 by the frictional force of the inner slider 22. The outer slider 23 can advance by compressing the return member 24 as a restoring force applying means integrally with the inner slider 22.

  Further, in a situation where the movement of the piston 16 or the inner slider 22 and the outer slider 23 is hindered when the pressure in the hydraulic chamber 13b is increasing, the friction force between the piston 16 and the inner slider 22 is greater. When a load is applied, the movable piston 16 or the inner slider 22 and the outer slider 23 can move forward with relative movement. Even in such a relative movement, the outer slider 23 can compress the return member 24.

  Thus, since the compressed return member 24 can apply a restoring force to the outer slider 23, the outer slider 23 moves the piston 16 that has moved forward to press the inner pad 17 by the restoring force. An appropriate amount can be returned integrally through 22. Accordingly, the distance (clearance) between the inner pad 17 and the outer pad 18 and the disk rotor 11 can be appropriately secured, and as a result, the occurrence of the friction pad drag phenomenon is suppressed, and a stable brake feeling is obtained. be able to.

b. Modified Example of First Embodiment In the first embodiment, an O-ring having an O-shaped cross section is used as the sealing member 21 and the return member 24 of the sealing mechanism 20. In this case, as the sealing member 21, in order to exhibit a good sealing function and reduce starting resistance and sliding resistance with the piston 16, for example, as shown in FIG. U packing) or a lip packing (V packing) having a substantially V-shaped cross section (not shown) can be used. Here, when lip packing is employed as the seal member 21, the lip on the side (outer peripheral side) that contacts the inner peripheral wall surface 13a1 of the caliper seal groove 13a contacts the outer peripheral surface of the piston 16, as shown in FIG. It is good to shape | mold so that it may become longer than the lip | rip of the side (inner peripheral side) to do.

  As described above, when the lip packing is adopted as the seal member 21, as shown in FIG. 7, the lip side is assembled so as to face the hydraulic pressure chamber 13b (high pressure side). In other words, a so-called self-sealing effect occurs, and good sealing performance can be ensured. In addition, due to such a self-sealing effect, the inner lip contacting the outer peripheral surface of the piston 16 is formed shorter to reduce the tightening margin (compression ratio) for the piston 16 than when an O-ring is used. Therefore, it is possible to reduce the starting resistance and sliding resistance that are generated when the piston 16 moves in the front-rear direction.

  In order to more effectively generate the restoring force applied to the slides of the inner slider 22 and the outer slider 23 as the return member 24, as shown in FIG. 7, for example, a highly elastic material (for example, a rubber material) ) And an annular ring having a substantially rectangular cross section can be employed. In this case, as shown in FIG. 7, a groove 23b for holding the return member 24 that is an annular shape is formed on the surface of the outer slider 23 that faces the opening side wall surface 13a3, and the return member 24 is formed in the groove 23b. It is good to assemble. As described above, when an annular ring having a substantially rectangular cross section is adopted as the return member 24, the elastic force accompanying the elastic deformation in the axial direction of the return member 24 with respect to the slide of the inner slider 22 and the outer slider 23. In addition to (restoring force), a resistance force (restoring force) when the return member 24 undergoes buckling deformation can be applied. Therefore, a sufficient restoring force for returning the inner slider 22 and the outer slider 23 to the original positions can be secured, and as a result, the piston 16 can be reliably returned to a predetermined position.

  In the first embodiment, the outer slider 23 is formed from a low friction material so as to reduce the frictional resistance with the inner peripheral wall surface 13a1 of the caliper seal groove 13a. In this case, in order to further reduce the frictional resistance, as shown in FIG. 7, for example, the surface facing the inner peripheral wall surface 13a1 of the outer slider 23 is formed in a stepped shape to reduce the contact area with the inner peripheral wall surface 13a1. It is also possible. Thus, even when the surface facing the inner peripheral wall surface 13a1 has a stepped shape, the outer slider 23 is molded from a highly rigid material, so that the inner slider 22 can be securely held and the frictional resistance can be reduced. By the reduction, the inner slider 22 can be integrated with the piston 16 and surely slide.

  Also in the modified example configured as described above, as shown in FIG. 8, when the inner slider 22 and the outer slider 23 slide from the original position following the advance of the piston 16, the return member 24 is moved to the outer slider 23. It compresses between the opening side wall surfaces 13a3. Thereby, the return member 24 can apply an elastic force (restoring force) according to the sliding amount of the outer slider 23, in other words, the compression amount, to the outer slider 23. Therefore, the same effect as the first embodiment can be obtained.

c. Second Embodiment In the first embodiment and its modifications, the sealing mechanism 20 is constituted by the sealing member 21, the inner slider 22, the outer slider 23, and the return member 24. In this case, as explained in the first embodiment, in particular, the seal member 21, the inner slider 22 and the return member 24 can all be molded from an elastic material (for example, a rubber material). , 24 can be implemented using a sealing mechanism 30 formed integrally. Hereinafter, although this 2nd Embodiment is described in detail, the same code | symbol is attached | subjected to the same part as the said 1st Embodiment and a modification, and the detailed description is abbreviate | omitted.

  Also in the second embodiment, as shown in FIG. 9, the seal mechanism 30 is accommodated in a caliper seal groove 13 a formed on the inner peripheral surface of the cylinder portion 13 of the caliper 12. And in the sealing mechanism 30 of this 2nd Embodiment, the elastic member which has the sealing function which the sealing member 21, the inner side slider 22, and the return member 24 in the said 1st Embodiment and a modification exhibit, respectively, a follow-up function, and a return function 31 and an outer slider 32 corresponding to the outer slider 23 in the first embodiment and the modification.

  As described above, the elastic member 31 is formed into a ring shape from an elastic material (for example, a rubber material), and is accommodated in the caliper seal groove 13a of the cylinder portion 13 as shown in FIG. , A seal portion 31a that faces the hydraulic chamber side wall surface 13a2, a slide portion 31b that contacts and follows the outer peripheral surface of the piston 16, and a return portion 31c that faces the opening side wall surface 13a3. Similar to the seal member 21 in the modification of the first embodiment, the seal portion 31a is a lip packing having a substantially U-shaped cross section (U packing) or a lip packing having a substantially V-shaped cross section (not shown) (V packing). Molded to accommodate. The slide portion 31b is in contact with the outer peripheral surface of the piston 16 by a predetermined pressing force, similarly to the inner slider 22 in the first embodiment and the modified example. In this case, in order to increase the frictional force on the inner peripheral surface of the slide portion 31b, for example, the inner peripheral surface is a smooth surface.

  Similar to the return member 24 in the modified example of the first embodiment, the return portion 31c is shaped so as to correspond to an annular shape having a substantially rectangular cross section. Further, in the elastic member 31 in the second embodiment, an accommodation groove 31d for accommodating the outer slider 32 is formed between the seal portion 31a and the return portion 31c and on the outer peripheral surface of the slide portion 31b. Yes.

  The outer slider 32 can easily slide with respect to the inner peripheral wall surface 13a1 of the caliper seal groove 13a without being deformed in accordance with the movement of the slide portion 31b, similarly to the outer slider 23 of the first embodiment and the modified example. Thus, it is formed in a ring shape from a highly rigid and low friction material (for example, Teflon (registered trademark)), and is accommodated in the accommodation groove 31 d of the elastic member 31. Here, as shown in FIG. 9, the outer slider 32 is formed with a protrusion 32a for preventing the return portion 31c from being deformed outward in the radial direction with respect to the surface facing the opening side wall surface 13a3 of the outer slider 32. Has been.

  Also in the seal mechanism 30 configured as described above, the slide portion 31b formed so as to increase the frictional force is formed on the outer peripheral surface of the piston 16 similarly to the seal mechanism 20 of the first embodiment and the modified example. The outer slider 32 which is made of a low friction material and is brought into contact with each other by the tension force is integrally held by the receiving groove 31d. Thereby, when the piston 16 moves in the front-rear direction, the slide portion 31b follows the piston 16 by friction and slides in the caliper seal groove 13a toward the return portion 31c. The outer slider 32 also slides in the caliper seal groove 13a toward the return portion 31c integrally with the slide of the slide portion 31b. At this time, since the outer slider 32 is molded from a low friction material, the outer slider 32 slides smoothly without causing a large frictional resistance against the inner peripheral wall surface 13a1 of the caliper seal groove 13a. Therefore, the slide part 31b and the outer slider 32 follow well with respect to the movement of the piston 16 in the front-rear direction.

  The outer slider 32 is accommodated in the accommodation groove 31d. As shown in FIG. 9, the seal portion 31a is disposed so as to contact the outer slider 32 and the hydraulic chamber side wall surface 13a2 of the caliper seal groove 13a, and the return portion 31c is formed between the outer slider 32 and the caliper seal groove 13a. It arrange | positions so that the opening side wall surface 13a3 may be contacted. In the following description, as shown in FIG. 9, the slide portion 31b and the return portion 31c are in contact with the outer slider 32, the hydraulic chamber side wall surface 13a2, and the opening side wall surface 13a3. The slide position of the outer slider 32 is referred to as the original position.

  For this reason, as shown in FIG. 10, when the slide part 31b and the outer slider 32 slide from the original position following the advance of the piston 16, the return part 31c is compressed between the outer slider 32 and the opening side wall surface 13a3. The Thereby, the return part 31c can apply to the outer slider 32 an elastic force (restoring force) corresponding to the sliding amount of the outer slider 32, in other words, the compression amount. Here, also in the second embodiment, when the slide portion 31b and the outer slider 32 slide following the advance of the piston 16, the slide amount from the original position of the slide portion 31b and the outer slider 32 is the return portion 31c. It is regulated by the maximum amount of elastic deformation. That is, the slide amount of the slide portion 31b and the outer slider 32 regulated by the maximum elastic deformation amount of the return portion 31c corresponds to the retract amount for returning the piston 16. Since the restoring force applied to the outer slider 32 from the return portion 31c is transmitted to the piston 16 through the slide portion 31b, the piston 16 is moved away from the inner pad 17 in the same manner as in the first embodiment. Acts as a return force to reverse the

  Further, since the seal portion 31a is formed from an elastic material, when the seal portion 31a is compressed between the outer slider 32 and the hydraulic chamber side wall surface 13a2, an elastic force (restoring force) is applied to the outer slider 32. Can do. Therefore, the slide portion 31b and the outer slider 32 are returned to their original positions by the elastic force (restoring force) applied from the return portion 31c and the elastic force (restoring force) applied from the seal portion 31a.

  The sealing mechanism 30 in the second embodiment also has the same pressure as the pressure in the hydraulic chamber 13b and the inner pad 17 with respect to the forward and backward movement of the piston 16, as in the sealing mechanism 20 in the first embodiment. Corresponding to the wear state of (and the outer pad 18), the piston 16 is followed and the piston 16 is returned. Therefore, the same effect as that of the first embodiment can be obtained by the second embodiment.

  In the second embodiment, the seal mechanism 30 can be constituted by the elastic member 31 and the outer slider 32. Thereby, in addition to the effect similar to the said 1st Embodiment, the number of parts accommodated in the caliper seal groove | channel 13a can be reduced significantly, As a result, an assembly property can be improved significantly.

d. Modified Example of Second Embodiment In the second embodiment, the seal part 31a and the return part 31c in the elastic member 31 of the seal mechanism 30 are implemented as different asymmetric shapes. In this case, as shown in FIG. 11, it is also possible to implement the seal part 31a and the return part 31c in the elastic member 31 of the seal mechanism 30 as substantially the same shape.

  In this case, if the seal portion 31a and the return portion 31c have substantially the same shape, the contact area of the slide portion 31b with the outer peripheral surface of the piston 16 increases, and the slide portion 31b and the piston 16 can be appropriately moved relative to each other. It can be difficult. Therefore, as shown in FIG. 11, the lubricating groove 31b1 is formed on the inner peripheral surface of the slide portion 31b (that is, the contact surface with the outer peripheral surface of the piston 16). As a result, it is possible to properly secure the tightening force, that is, the frictional force between the slide portion 31b and the piston 16, and to stably slide the slide portion 31b. As a result, the return function for returning the piston 16 is stabilized. Can do.

  Also in the modified example configured as described above, as shown in FIG. 12, when the slide portion 31 b and the outer slider 32 slide from the original position following the advance of the piston 16, the return portion 31 c becomes the outer slider 32. And the opening side wall surface 13a3. Thereby, the return part 31c can apply to the outer slider 32 an elastic force (restoring force) corresponding to the sliding amount of the outer slider 32, in other words, the compression amount. Therefore, the same effect as the second embodiment can be obtained.

  In carrying out the present invention, the present invention is not limited to the above-described embodiments and modifications, and various modifications can be made without departing from the object of the present invention.

  For example, in the first embodiment and the modification, the seal mechanism 20 is accommodated in the caliper seal groove 13a. In this case, for example, the sealing member 21, the inner slider 22, the outer slider 23, and the return member 24 can be separated and provided in the cylinder portion 13. In this case, the cylinder portion 13 is slightly used. The same effects as those of the first embodiment and the modified example can be expected except that additional machining is performed on the inner peripheral surface.

  Moreover, in the said 2nd Embodiment and the modification, as the elastic member 31 of the sealing mechanism 30, the seal part 31a, the slide part 31b, and the return part 31c were integrally shape | molded and implemented. In this case, as the elastic member, the seal portion 31a and the slide portion 31b can be formed integrally, or the slide portion 31b and the return portion 31c can be formed integrally. In this case, for example, by housing the elastic member thus formed in the caliper seal groove 13a, the same effect as in the second embodiment and the modified example can be expected.

  Further, in each of the above embodiments and modifications, the seal mechanisms 20 and 30 are applied to a caliper floating disc brake device that presses only the inner pad 17 with the piston 16. In this case, it is also possible to employ a caliper-fixed disc brake device having a piston that presses the inner pad and the outer pad individually. In this case, by providing a sealing mechanism configured in the same manner as each of the above-described embodiments and modifications for each of the pistons that press the inner pad and the outer pad, the same as in the above-described embodiments and modifications. The effect is obtained.

DESCRIPTION OF SYMBOLS 11 ... Disc rotor, 12 ... Caliper, 13 ... Cylinder part, 13a ... Caliper seal groove, 13b ... Hydraulic pressure chamber, 16 ... Piston, 17 ... Inner pad, 18 ... Outer pad, 20 ... Seal mechanism, 21 ... Seal member, 22 ... inner slider, 23 ... outer slider, 24 ... return member, 30 ... sealing mechanism, 31 ... elastic member, 32 ... outer slider

Claims (9)

A disk rotor that rotates integrally with the wheel around the rotation axis, and a piston that presses the friction pad facing the friction surface of the disk rotor toward the friction surface as the brake fluid pressure increases, and the piston moves forward and backward. A caliper having a cylinder that supports the seal, and a seal that is accommodated in the cylinder of the caliper and seals the piston, and moves the piston moved forward to press the friction pad as the brake fluid pressure decreases. In a disc brake device having a mechanism,
The sealing mechanism,
Sealing means for sealing between the inner peripheral surface of the cylinder and the outer peripheral surface of the piston;
A highly rigid outer slider that follows the piston and slides against the inner circumferential surface of the cylinder, and is provided between the outer slider and the piston. The piston, the outer slider, and the inner slider when a predetermined load is applied to the piston, the outer slider, and the inner slider as the brake fluid pressure increases. Following means for allowing relative movement with
A restoring force applying means that is compressed by the movement of the outer slider of the following means following the advance of the piston, and applies a restoring force against the compression to the outer slider of the following means as the brake fluid pressure decreases; Consisting of
The follow-up means, when the outer slider and the inner slider with an increase of the brake hydraulic pressure is advanced integrally to follow the forward movement of the piston, the forward of the piston is inhibited, the When the predetermined load set by the brake fluid pressure is applied, the outer slider and the inner slider are allowed to move forward with respect to the stopped piston , and the restoring force is applied as the brake fluid pressure decreases. A disc brake characterized in that the restoring force applied to the outer slider by means is transmitted to the piston via the inner slider, and the piston, the outer slider and the inner slider are moved backward together. apparatus. In the disc brake device according to claim 1,
A disc brake device characterized in that the sealing means, the follow-up means, and the restoring force applying means constituting the sealing mechanism are accommodated in a seal groove formed in the cylinder of the caliper. In the disc brake device according to claim 2,
The disc brake device, wherein the sealing means, the follow-up means, and the restoring force applying means are arranged in the seal groove in the forward direction of the piston. In the disc brake device according to claim 1,
The following means is
As the brake fluid pressure increases, the outer slider and the inner slider follow the advance of the piston and move forward integrally, so that the piston presses the friction pad and the friction pad becomes the disc. A disc brake device, wherein the outer slider and the inner slider are allowed to advance when the piston is pressed against the friction surface of the rotor and the advance of the piston is inhibited. In the disc brake device according to claim 1,
The magnitude of the frictional force between the inner peripheral surface of the cylinder and the outer peripheral surface of the outer slider of the follower means is the friction force between the inner peripheral surface of the inner slider of the follower means and the outer peripheral surface of the piston. A disc brake device characterized by being smaller than the size. In the disc brake device according to claim 1,
The predetermined load set in advance is
2. A disc brake device according to claim 1, wherein the disc brake device is preset according to a magnitude of a frictional force between an inner peripheral surface of the inner slider and the outer peripheral surface of the piston. In the disc brake device according to claim 1,
2. A disc brake device according to claim 1, wherein contact surfaces of the outer slider and the inner slider of the follow-up means are formed in a concavo-convex shape to fit each other. In the disc brake device according to claim 1,
The disc brake device, wherein the sealing means and the inner slider of the following means, or the inner slider and the restoring force applying means of the following means are integrally formed. In the disc brake device according to claim 8,
A disc brake device comprising a groove formed in a circumferential direction with respect to an inner peripheral surface contacting the outer peripheral surface of the piston of the integrally formed inner slider.

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