JP4259440B2 - Disc brakes for railway vehicles - Google Patents

Description

  The present invention relates to a disc brake (caliper brake) installed in a railway vehicle, and more particularly, to a disc brake having a drag reduction effect by providing a retraction mechanism that pulls back a pad when pressure is released.

  In the vehicular disc brake, when the pad comes into contact with the disc during non-braking, a so-called drag problem occurs, the power performance of the vehicle decreases, and the wear of the pad is promoted. Therefore, a method of preventing a drag by providing a retraction mechanism for forcibly pulling back the brake piston by a certain amount when the brake is released is employed (see FIG. 1 of Patent Document 1 below).

  In the retraction mechanism disclosed in Patent Document 1, a second piston urged in the return direction by an elastic body is fitted on the outer periphery of the brake piston, and braking is performed when the second piston is pressurized (during braking). Advances a certain amount under the fluid pressure. The second piston returns to its original position by the force of the elastic body when the pressure is released, and at this time, the brake piston inserted with an appropriate sliding resistance inside the second piston is pulled back together. For this reason, the pad is no longer pressed against the disc, and drag is suppressed.

  However, in the conventional retraction mechanism that pulls back only the brake piston, the pad remains in the pressed position, so that the railcar disc brake is particularly insufficient in suppressing dragging. In a railway vehicle disc brake in which the caliper is attached to the vehicle body and the disc is attached to the carriage, the vehicle body may be shaken while the pad is pressed against the disc, and the caliper and the disc may move relative to each other in the disc axial direction. As a result, the brake piston has already returned to the non-braking position while the pad is pressed against the disc, and the brake piston contacts the pad and the pad is pressed against the disc even during non-braking. appear.

  Therefore, the retraction mechanism of FIG. 6 was considered as a countermeasure. This retraction mechanism is an application of the prior art, in which a retractor rod 7 is inserted into the caliper 1 so as to be slidable in the disk axial direction, a retractor pin 8 is inserted inside the retractor rod 7, and the retractor rod 7 The retractor bush 9 provided inside is fitted to the outer periphery of the retractor pin 8 and the retractor pin 8 is urged in the return direction by the retractor spring 10. Further, the guide plate 4 is connected to the retractor rod 7, and the guide plate 4 is connected to the pad 5.

  In the retraction mechanism of FIG. 6, when the fluid pressure is introduced into the cylinder 2 and the brake piston 3 is pushed out, the retractor rod 7 moves forward by the force transmitted through the guide plate 4. Since the pin restraining force by the retractor bush 9 exceeds the force of the retractor spring 10, the retractor spring 10 moves toward the disk 6 by a certain amount while being compressed.

  At the time of pressure removal, the retractor rod 7 is pulled back through the retractor pin 8 by the restoring force of the retractor spring 10, and the pad 5 is also pulled back accordingly.

Further, when the pad movement amount at the time of pressurization becomes larger than the movement amount of the retractor pin 8, a relative movement that absorbs the difference in the movement amount occurs between the retractor rod 7 and the retractor pin 8. Therefore, the caliper 1 and the disc 6 If the relative position does not change, the return amount by the retraction mechanism is always kept constant. However, in a railway vehicle disc brake, the caliper and the disc move in the disc axis direction relative to each other as described above. When the relative movement occurs in a pressurized state, the retractor rod 7 and the retractor pin 8 that are pulled by the guide plate 4 are pushed back to return the retractor spring 10 to a restoring state, and when the pressure is released, the retractor rod 7 is moved. The power to pull back is lost. As a result, the pad does not return and dragging occurs.
JP-A-4-29

  This invention provides a highly reliable retraction mechanism that does not lose the force of pulling back the pad when the pressure is released even if the axial relative movement of the caliper and the disk occurs under pressure. It is an object to provide a disk brake for a railway vehicle.

  In order to determine the above-described problems, in the present invention, a retractor holder assembled to be able to advance quantitatively with respect to the caliper by using fluid pressure as a driving force and to be retractable from a fixed advancement end, and a predetermined amount with respect to the retractor holder. A retractor rod assembled so as to be relatively movable in the axial direction of the disk with a sliding resistance, and retractor means for retracting the retractor holder from the forward end, and the retractor on the pad that is pressed by a brake piston and slidably contacts the disk Provided is a railway vehicle disc brake including a retraction mechanism configured by connecting rods.

  The retractor holder is provided with an auxiliary piston that operates by fluid pressure and moves forward by a fixed amount. The auxiliary piston is connected to the retractor holder and moved forward by the driving force of this auxiliary piston, and a piston that operates by receiving fluid pressure is separately provided. It is possible to use a piston provided by the piston, and either of them may be adopted.

  In the retraction mechanism employed in the present invention, it is preferable that the retractor rod is provided at a position independent of the brake piston and connected to the pad, and the brake piston is not connected to the pad. The brake piston may be connected to the pad.

  In the retraction mechanism employed in the present invention, a retractor holder that operates using fluid pressure as a driving force advances a certain amount when compressed to compress the elastic body. The retractor rod connected to the pad can move relative to the retractor holder in the axial direction of the disk with a predetermined sliding resistance. When the relative movement of the caliper and the disk occurs under pressure, the retractor rod Slips with respect to the retractor holder and only the retractor rod is pushed back.

  Therefore, the compressed state of the elastic body is maintained, and when the pressure is released, the retractor rod is reliably returned by the elastic restoring force of the elastic body and the pad is forcibly pulled back by a certain amount. Thereby, dragging during non-braking is prevented, and the purpose of improving the power performance of the vehicle and suppressing the wear of the pad is achieved.

  Embodiments of the present invention will be described below with reference to FIGS. 1 to 5 of the accompanying drawings. FIGS. 1A and 1B show the overall configuration of the disc brake of the present invention, and FIG. 2 shows details of the pad pressing mechanism and the retraction mechanism provided on the caliper 1 (only one side is disclosed). The disc brake includes a caliper 1 that straddles the disc, a brake piston 3 inserted into a cylinder 2 of the caliper 1, a guide plate 4, a pad 5 that includes a friction material 5a and a back plate 5b, and pads 5 and 5 that are opposed to each other. A disc 6 to be sandwiched and a pair of opposing torque receivers 11 and 11 are provided.

  The caliper 1 is attached to the vehicle body in the orientation shown in FIG. 1A, that is, the direction in which the pair of torque receivers 11 and 11 are arranged on the top side and the ground side, and the disc 6 is provided on the cart side. (In FIG. 1, the disk 6 is mounted on the wheel 20). The guide plate 4 is detachably connected to the back plate 5b of the pad 5.

  The illustrated disc brake is further provided with a retraction mechanism 12 for returning the pad 5 together with the brake piston 3. The retraction mechanism 12 includes a retractor rod 7, a retractor spring 10, a retractor holder 13, a piston holder 14, and a retractor plate 15.

  The retractor holder 13 is slidably incorporated in a hole 16 in the disk axial direction provided in the caliper 1, and the retractor rod 7 is slid to a predetermined sliding resistance inside the retractor holder 13 urged in the return direction by the retractor spring 10. And the tip of the retractor rod 7 is connected to the guide plate 4. The sliding resistance of the retractor rod 7 is given here with an O-ring 17 interposed between it and the retractor holder 13, but it can also be given using a member other than the O-ring, such as a coiling bush.

  In the illustrated disc brake, the retractor spring 10 is used. However, the retractor means only needs to have a function of urging the retractor holder in the return direction, such as an elastic body other than the spring, hydraulic pressure, pneumatic pressure, etc. It may be due to the fluid pressure.

  The piston holder 14 is composed of an annular piston inserted into the cylinder 2, and receives a braking fluid pressure introduced into the cylinder 2 on the back surface and advances a predetermined amount L. The brake piston 3 is inserted inside the piston holder 14, and the retractor holder 13 is connected to the piston holder 14 via a retractor plate 15. In the figure, reference numerals 18 and 19 denote seals disposed between the cylinder 2 and the piston holder 14 and between the piston holder 14 and the brake piston 3.

  In the example disc brake configured as described above, the brake piston 3 advances by receiving the fluid pressure introduced into the cylinder 2 and presses the pad 5 via the guide plate 4. The piston holder 14 also receives the fluid pressure in the cylinder 2 and advances to a position regulated by the caliper 1 while compressing the retractor spring 10, and retracts the retractor holder 13 mechanically connected via the retractor plate 15. Pull together. At this time, the retractor rod 7 is also moved by the guide plate 4 and advances at the same time, and in this state, the pad 5 is pressed against the disk 6 to be braked. When the pressure is released thereafter, the retractor spring 10 is elastically restored, and the retractor holder 13 and the piston holder 14 connected thereto are pulled back to their original positions.

  This pull-back is performed reliably even when one side of the caliper 1 approaches the disk 6 in a pressurized state and is subsequently depressurized. When one side of the caliper 1 approaches the disk 6 in the pressurized state, the retractor rod 7 incorporated in the approaching caliper is pushed back. At this time, the piston holder 14 receives the fluid pressure in the cylinder 2 and is held in the forward position. For this reason, the retractor rod 7 slides in the retractor holder 13 and is pushed back, and the retractor holder 13 is held in the forward position. Will remain. Thereby, the compressed state of the retractor spring 10 is maintained, and the pad 5 is pulled back by the force of the spring when the pressure is released.

  When the pad 5 is worn, a slip corresponding to the amount of wear occurs between the retractor holder 13 and the retractor rod 7 during pressurization. Further, the return amount of the retractor rod 7 at the time of depressurization is determined by the stroke of the piston holder 14, and the return amount of the pad 5 and the stroke at the next pressurization are always constant.

  In the retraction mechanism employed in the disc brake of the present invention, a retractor spring 10 for returning the retractor holder 13 and the pitons holder 14 may be provided between the piston holder 14 and the caliper 1 as shown in FIG. Further, as shown in FIG. 4, a secondary cylinder 21 communicating with the cylinder 2 is provided in the caliper 1, and a retractor holder 13 is inserted therein, and the retractor holder 13 is made to function as a piston so that a certain amount of fluid pressure is applied for braking. The structure may be advanced, and this structure does not require the piston holder 14 and the retractor plate 15.

  In addition, if there is no worry that the brake piston 3 may be damaged and damaged, the brake piston 3 may be mechanically connected to the guide plate 4 as shown in FIG. When one side of the caliper 1 approaches the disc 6 in the pressurized state, the brake piston 3 incorporated in the caliper on the approaching side slides against the piston holder 14 held in the forward movement position, thereby pushing back. The compressed state of the retractor spring 10 is maintained. Therefore, the structure of FIG. 5 in which the retractor holder, the dedicated retractor rod, and the retractor plate are omitted can produce the effects of the present invention.

(A) A side view showing an overall configuration of an example of a disc brake of the present invention, (b) a plan view of the brake of the above. Enlarged sectional view of the portion along the line II-II in FIG. Sectional drawing which shows the example which provided the retractor spring between the piston holder and the caliper Sectional drawing which shows the example which advances a retractor holder itself Sectional view showing an example where the brake piston is also used as a retractor rod Sectional drawing which shows the retraction mechanism of the pad considered from prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Caliper 2 Cylinder 3 Brake piston 4 Guide plate 5 Pad 5a Friction material 5b Back plate 6 Disc 7 Retractor rod 10 Retractor spring 11 Torque receiver 12 Retraction mechanism 13 Retractor holder 14 Piston holder 15 Retractor plate 16 Hole 17 O-rings 18 and 19 Seal 20 Wheel 21 Sub cylinder

Claims (5)

  Retractor holder assembled with fluid pressure as driving force so that it can move forward with respect to the caliper and retractable from the fixed amount forward end, and with relative sliding movement with respect to the retractor holder with a predetermined sliding resistance A retraction mechanism comprising: an assembled retractor rod; and a retractor means for retracting the retractor holder from the forward end, and the retractor rod being connected to a pad that is pressed by a brake piston and slidably contacts the disc. Equipped with a railway vehicle disc brake.   2. The railway vehicle disk according to claim 1, wherein an auxiliary piston is provided that is actuated by fluid pressure and moves forward quantitatively, the auxiliary piston is connected to the retractor holder, and the retractor holder is advanced by the driving force of the auxiliary piston. brake.   2. The disk brake for a railway vehicle according to claim 1, wherein the retractor holder is constituted by a fluid pressure actuated piston, and the piston receives a fluid pressure and moves forward quantitatively.   The disc brake for a railway vehicle according to any one of claims 1 to 3, wherein the retractor rod is provided at a position independent of the brake piston, the retractor rod is connected to the pad, and the brake piston is not connected to the pad.   The railway vehicle disc brake according to any one of claims 1 to 3, wherein the brake piston also serves as the retractor rod.

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