JP2008261377A - Braking device incorporating vibration suppression means in hollow piston - Google Patents

Abstract

When a brake disk rotates while being sandwiched between pads, the traction force based on frictional contact from the disk acting on each part of the friction surface of the pad in contact with the disk does not change uniformly over time. As the piston is a hollow piston, it is suppressed in association with the fact that the piston is a hollow piston.
A mass member having a protrusion protruding toward the pad along the central axis in the chamber space of the hollow piston or a disk member immersed in a liquid layer is provided, and the pad is engaged with the pad from the back surface at the tip of the protrusion. Provide combined vibration control means.
[Selection] Figure 1

Description

  The present invention relates to a braking device in which a pad is pressed against a rotating disk by a hollow piston to brake the rotation of the disk.

  2. Description of the Related Art As a braking device for automobiles or the like, there is known a braking device that brakes the rotation of a disk by pressing a pad with a piston by means of a piston. In such a braking device, the piston is placed inside to reduce the weight of the device. It is known to form as a hollow piston with a chamber space.

The braking device copes with the fact that vibration and noise may be generated during the braking operation. In particular, in a braking device using a hollow piston, a weight is loaded in the chamber space inside the hollow piston to cause vibration. What is to be attenuated is described in Patent Document 1 below. In Patent Document 2 below, a stepped inner hole formed in a piston of a working cylinder connected to a master cylinder via a hydraulic pipe and communicating with a hydraulic chamber of the working cylinder through a small diameter portion, A stepped piston assembled to the stepped bore so as to be movable in the axial direction; a seal ring that seals between a small diameter portion of the stepped piston and the small diameter portion of the stepped inner hole; and a large stepped bore. A hydraulic pressure composed of a stopper that is assembled to the diameter portion to define the axial movement amount of the stepped piston, and a damper spring that biases the stepped piston toward the stepped portion of the stepped inner hole. A vibration absorber is described.
JP 2002-213506 A JP-A-5-87169

  Various mechanisms can be considered for the generation of vibration and noise during braking in the braking device that presses the pad against the rotating disk and brakes the rotation of the disk. When the disc rotates while sandwiched between the pads, the traction force based on the frictional contact from the disc acting on the friction surface of the pad in contact with the disc does not change uniformly with time in each part of the friction surface, On the other hand, the support part of the pad is not flush with the friction surface of the pad, but is positioned perpendicularly to the friction surface. The variation in frictional traction force from the acting disk acts as a variable moment that tilts the pad in various directions with respect to the pad. It is considered due to the fact that the pad is excited by changes dynamically.

  The present invention pays attention to the above-described vibration generation mechanism in a braking device in which a rotating disk is braked by a pad pressed against the peripheral edge thereof. In connection with the fact that the piston to be pressed is a hollow piston, it is an object to suppress the generation of vibration and noise during braking.

  In order to solve the above problems, the present invention provides a braking device configured to press a pad against a rotating disk by a hollow piston having a chamber space therein to brake the rotation of the disk, and the hollow piston A mass member having a projection provided in the chamber space and projecting toward the pad along the central axis of the hollow piston, and engaged with a pad support member that supports the pad from the back surface at the tip of the projection The present invention proposes a braking device provided with vibration damping means.

  The mass member may be frictionally engaged with the inner peripheral wall surface of the hollow piston, and a spring may be provided to elastically bias the mass member toward the pad.

  Alternatively, the mass member may be immersed in a liquid layer loaded in the chamber space of the hollow piston, in which case the liquid layer is enclosed in a bag mounted in the chamber space of the hollow piston. May have been.

  As described above, when a variable moment that tilts the pad in various directions acts on the pad, in particular, if the pad is a pad that is supported at the peripheral edge by the hollow piston, the pad has a minute vibrational tilt, but the hollow piston It tilts about a fulcrum somewhere along the annular support part by the peripheral part. On the other hand, including a mass member provided in the chamber space using the chamber space of the hollow piston and having a protrusion protruding toward the pad along the central axis of the hollow piston, the pad at the tip of the protrusion If a vibration damping means for engaging the pad support member for supporting the pad from the back side is provided, the position of the hollow piston at the peripheral portion of the hollow piston along the annular support portion can be used as a fulcrum at the center of the pad. Can capture the vibration bias that appears without fail, and exert a damping effect on the pad.

  If the mass member is frictionally engaged with the inner peripheral wall surface of the hollow piston, the friction damping action by the friction engagement can be added to the damping action by the inertia of the mass member. In addition, if a spring that elastically biases the mass member toward the pad is provided, by adjusting the spring force, the natural frequency of the pad is deviated from the above-described fluctuation moment generation period range. , Resonance can be avoided and the damping effect can be enhanced.

  Alternatively, when the mass member is immersed in a liquid layer loaded in the chamber space of the hollow piston, the mass member is moved in the liquid layer by resistance acting on the liquid layer. It is possible to exert a vibration control action on the pad. In that case, if the liquid layer is enclosed in a bag mounted in the chamber space of the hollow piston, the liquid layer and the mass member are previously incorporated in the bag, and then inserted into the hollow piston. This makes it easier to install the braking device.

  FIG. 1 is an exploded sectional view showing one embodiment of a braking device according to the present invention. The illustrated braking device is a disc brake for a vehicle. In the figure, 10 is a disk, only its peripheral edge is shown in the figure, and is not shown in the figure so as to rotate around a lower central axis that does not appear in the figure. It is supported by a rotating shaft (axle). Reference numerals 12 and 14 denote a pair of pads that sandwich and brake the peripheral edge of the disk 10 from both sides.

  Reference numeral 16 denotes a caliper, which is supported by a support means (not shown) so as to be displaceable left and right in the figure with respect to the disk 10. The pad 12 is supported at one end of the caliper 16 via a back metal 18 and a shim 20. A cylinder bore 22 is formed at the other end portion of the caliper 16, and a hollow piston 24 is slidably mounted along the central axis of the cylinder bore. The pad 14 is supported at its annular peripheral edge by a piston 24 through a back metal 26 and a shim 28. A hydraulic chamber 30 is formed in the cylinder bore 22 between the end wall of the cylinder bore 22 and the closed end wall of the hollow piston 24. The hydraulic pressure is selectively transmitted to the hydraulic chamber by a hydraulic conduit (not shown). By being supplied, the piston 24 is driven in a direction in which it is pushed out from the cylinder bore 22, and accordingly, the pads 12 and 14 sandwich the periphery of the disk 10 from both sides to brake its rotation. Reference numeral 32 denotes an annular seal that keeps liquid leakage in the sliding portion between the cylinder bore 22 and the piston 24, and reference numeral 34 denotes a tubular bellows that captures oil leaking across the annular seal.

  A chamber space is formed inside the hollow piston 24, and in the illustrated example, a disk-shaped mass member 36 is inserted into the chamber space with an annular shoe member 38 attached to the peripheral portion thereof. ing. The mass member 36 may be made of a suitable metal material. The annular shoe member 38 is made of a relatively soft member such as rubber, and is preferably in a state of being frictionally engaged with the peripheral wall of the cylinder bore 22 with an appropriate pressure. The mass member 36 includes a protrusion 40 and abuts against the central portion of the shim 28 at the tip thereof. This abutting state is held in a pressed state by a compression coil spring 42 interposed between the mass member 36 and the end wall of the cylinder bore 22, and the pad 14 and the back surface thereof are interposed by the spring via the mass member 36. A predetermined spring force is exerted on the combination of the back metal 26 and the shim 28 which are the pad support members that are supported from each other.

  With the configuration as described above, hydraulic pressure is supplied from the state shown in the figure into the hydraulic chamber 30, the piston 24 is driven in a direction to be pushed out from the cylinder bore 22, and the pads 12 and 14 are connected to the peripheral edge of the disk 10 via the caliper 16. At the time of braking pressed against both sides, the pad, in particular, the pad 14 supported by the annular peripheral edge of the hollow piston 24 is caused by variation in frictional traction force exerted by frictional engagement with the disk 10 at each part of the friction surface. When the pad 14 is tilted about the annular support portion as a fulcrum, the inertia of the mass member 36, and in addition to that, between the shoe member 38 and the cylinder bore 22. The frictional resistance against sliding of the pad 14 suppresses the displacement due to the tilting of the pad at the center of the pad 14 and controls the pad 14. It can give the action. The spring force of the compression coil spring 42 is appropriately adjusted so that the natural frequency of the pad 14 or a combination of the back metal 26 and shim 28 supporting the pad 14 or the brake structure including the caliper 16 and the other pad 12 is supported. Is deviated from the fluctuation moment generation period range described above, it is possible to more effectively prevent large vibrations and noises from being generated in the braking device due to resonance of the pad 14 and the caliper 16 that supports the pad 14. .

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FIG. 2 is an exploded cross-sectional view showing another embodiment of the braking device according to the present invention. In FIG. 2, portions corresponding to the portions shown in FIG. 1 are denoted by the same reference numerals as in FIG. In this embodiment, the means for giving a damping action to the pad 14 includes a liquid layer 44 provided in a chamber space inside the hollow piston 24 and a disk member 46 immersed therein. . The disk member 46 includes a protrusion 48 and is connected to the central portion of the shim 28 at the tip. Moreover, in this example, the liquid layer 44 is loaded in the bag 50, and the protrusion 48 extends through the liquid nest through the hole 52 opened in a part thereof. The protrusion 48 may be slidable with respect to the hole 52 at a portion penetrating the hole 52. However, if the bag is made of a soft material such as rubber or soft plastic, the protrusion 48 has a hole. It may be fixed to the bag at a portion penetrating 52.

  Even in such a configuration, the pad 14 tilts and vibrates due to the above-described moment that fluctuates in a vibrational manner due to the resistance acting from the liquid layer when the disk member 46 moves in the horizontal direction in the drawing within the liquid layer 44. Therefore, it is possible to prevent the occurrence of large vibrations and noises in the pad and the caliper due to resonance by giving a vibration damping action.

  Although the present invention has been described in detail with reference to two embodiments, it will be apparent to those skilled in the art that various modifications can be made to these embodiments within the scope of the present invention.

1 is an exploded sectional view showing a braking device according to the present invention in one embodiment. FIG. 3 is an exploded sectional view showing a braking device according to the present invention in another embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Disc, 12, 14 ... Pad, 16 ... Caliper, 18 ... Back metal, 20 ... Shim, 22 ... Cylinder bore, 24 ... Piston, 26 ... Back metal, 28 ... Shim, 30 ... Hydraulic chamber, 32 ... Ring seal, 34 ... Bellows, 36 ... mass member, 38 ... shoe member, 40 ... projection, 42 ... compression coil spring, 44 ... liquid layer, 46 ... disc member, 48 ... projection, 50 ... bag, 52 ... hole

Claims (5)

  A braking device configured to brake the rotation of the disk by pressing the pad against the rotating disk by a hollow piston having a chamber space inside, and a central axis of the hollow piston provided in the chamber space of the hollow piston Including a mass member having a protrusion protruding toward the pad along the surface, and provided with vibration damping means for engaging with a pad support member that supports the pad from the back surface at the tip of the protrusion. Braking device to do.   The braking device according to claim 1, wherein the mass member is frictionally engaged with an inner peripheral wall surface of the hollow piston.   The braking device according to claim 1, wherein a spring that elastically biases the mass member toward the pad is provided.   The braking device according to claim 1, wherein the mass member is immersed in a liquid layer loaded in a chamber space of the hollow piston.   The braking device according to claim 4, wherein the liquid layer is sealed in a bag mounted in a chamber space of the hollow piston.

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