JP2008190559A - Disc brake with water-cooled disc - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more properly cool a disc brake while avoiding inconvenient problems with the disc brake cooled by cooling a pad or mist jetted directly to the surface of a disc in contact with the pad. <P>SOLUTION: The vehicular disc brake comprises the disc for engaging with the pad, whose peripheral edge has double walls and on which an air-cooling blade train is formed between the double walls. Herein, a means is provided for jetting water from the radial inside of the blade train to the blade train. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle disc brake, and more particularly to a disc brake in which a disc is water-cooled according to a temperature rise state of a brake pad.

A cooling chamber is provided in at least one of the pad or the pressing member that presses the pad against the disk, in response to a phenomenon called fading in which the braking force is reduced when overheating occurs in the disk brake pad. The following Patent Document 1 describes that cooling water is supplied by a cooling water supply device. Further, the following Patent Document 2 describes that in a disc brake equipped with the same pad water cooling means, an on-off valve that automatically opens when the temperature of the pad rises in the middle of the cooling water supply passage is described. ing. On the other hand, in Patent Documents 3 and 4 below, a spray means having a nozzle that opens toward a disk is attached to a caliper of a disk brake, and a mixed mist of cooling water and air is produced by the spray means according to the vehicle speed and the brake temperature. It is described that the disc brake is cooled by spraying the nozzle to the surface in contact with the disc pad from the nozzle.
JP-A-2-159431 JP-A-5-187468 JP-A-5-215158 JP-A-5-215159

  The friction material composing the pad is generally made of a porous structure, and is inferior in thermal conductivity as compared with a normal metal material. Therefore, as described in Patent Document 1 or 2, the pad has a zigzag shape or When the rake-shaped cooling water passage is provided to cool the pad, there is a concern that the entire pad is difficult to be uniformly cooled, and that a portion where cooling is insufficient is likely to occur. On the other hand, as described in Patent Documents 3 and 4, if water is sprayed directly onto the surface of the disk in contact with the pad, there is a concern that the braking force becomes unstable.

  By the way, as a disk of a disk brake, there is known a disk in which a peripheral edge of a disk engaged with a pad is a double wall, and an air cooling blade row is formed between the double walls. The present invention provides a peripheral double wall structure and a blade provided therebetween in a disc brake having a disc in which a peripheral portion is formed as a double wall and an air cooling blade row is formed therebetween. Effective use of the rows avoids the disadvantages of disc brake cooling or mist spraying directly onto the surface of the disc pad by cooling the pad, as described above, to make the disc brake more suitable. The task is cooling.

  In order to solve the above-described problems, the present invention provides a vehicle having a disk in which a peripheral edge of a disk engaged with a pad is a double wall, and an air cooling blade row is formed between the double walls. The present invention proposes a disc brake characterized by having means for injecting water from the inside in the radial direction of the blade row toward the blade row.

  The water spraying means is disposed along the radially inner side of the blade row and is spaced along the outer peripheral edge thereof, and has an annular tube having a plurality of nozzle openings opened toward the blade row, and into the tube. Pressure water source means for pumping water.

  The pressure water source means is activated when the temperature of the pad exceeds a predetermined limit value, or when the disc brake is for a vehicle, the pressure water source means is estimated based on the driving state of the vehicle. It may be activated when the temperature of the applied pad exceeds a predetermined limit value.

  When the disc brake is for a vehicle, the pressure water source means determines whether the pad temperature exceeds a first limit value or whether the pad temperature estimated based on the vehicle operating condition exceeds a second limit value. It may be activated when at least one of them occurs, in which case the second limit value may be set lower than the first limit value.

  A conventionally known blade row in a vehicle disc brake having a disc in which a peripheral edge portion of a disc engaging with a pad is a double wall and an air cooling blade row is formed between the double walls. The blade is intended to cool the peripheral edge engaged with the pad of the disk by causing an air flow to radially traverse the blade array from the radially inner side to the radially outer side as the disk rotates. If a means for injecting water from the radially inner side of the row toward the blade row is provided, water is included in the air flow across the blade row, and the cooling effect is markedly greater than cooling by the air flow alone. A high air / water mixture flow can cool the blade row as needed, thereby cooling the surface of the disk in contact with the pad and cooling the pad with the disk. Ri, it is possible to suppress that the pad becomes the overheated state. In this case, since water is supplied inside the double wall structure at the periphery of the disc, the dry contact state between the disc and the pad is not disturbed by the water, and there is no risk that the braking will become unstable. . Further, since the peripheral edge of the disk is cooled by water while being rotated, it is uniformly cooled, and the pad contacting the peripheral edge of the rotating disk is uniformly cooled over the entire surface, and the entire pad is uniformly cooled. Also, the cooling is very effective because it takes place from the surface where heat is generated in the pad.

  The water spraying means is disposed along the radially inner side of the blade row, and is annularly spaced along the outer peripheral edge thereof and has a plurality of nozzle openings that open toward the blade row, and water is introduced into the tube. If the pressure water source means for pumping is included, the cooling water can be uniformly supplied to the annular blade row by the addition of a simple device called an annular tube having a plurality of nozzle openings spaced along the outer peripheral edge. The pressure water source means for pumping water into the pipe can also be obtained by a simple pump, a water storage tank and, if necessary, a device with an on-off valve added thereto. Alternatively, in the case of a vehicle, a pressure water source means for supplying water to the wiper is already provided, and the water cooling of the disc brake according to the present invention is not always required during the operation of the vehicle, and the braking load is not Since the pressure water source means for disc brake water cooling can be covered by sharing the pressure water source means for the wiper because it is high and should be performed only when there is a risk of overheating of the pad. .

  Since the temperature of the pad is detected by an appropriate temperature sensor, if the pressure water source means is activated when the temperature of the pad exceeds a predetermined limit value, the pad overheating prevention intended by the present invention is achieved. Can achieve the full effect by keeping the required water tank capacity to a minimum.

  On the other hand, when the disc brake is used for a vehicle, the pad temperature can be estimated based on the driving state of the vehicle, so that the pressure water source means has the pad temperature estimated based on the driving state of the vehicle exceeding a predetermined limit value. The present invention can be implemented without providing a pad temperature sensor. In addition, if the pad temperature is estimated based on the driving state of the vehicle, when the pad may be overheated, it can be predicted from the driving state of the vehicle. Rather than controlling, a higher pad overheating prevention effect can be obtained with a smaller amount of water.

  The disc brake is for a vehicle, and the pressure water source means has at least a pad temperature exceeding a first limit value or a pad temperature estimated based on the operating condition of the vehicle exceeding a second limit value. If it is activated when either one occurs, the pad temperature is estimated based on the driving state of the vehicle, and the pad overheating prevention control is performed as described above. The control can reliably achieve prevention of pad overheating. In particular, if the second limit value is set lower than the first limit value at that time, the estimated pad temperature indicates that the pad temperature is approaching a certain first limit value from the driving state of the vehicle. The pressure water source means can be activated so that it can be sensed when a certain lower limit value is reached and the pad temperature does not approach the first limit value in advance to prevent the pad temperature from rising. In addition, when the pad temperature actually rises to the first limit value due to some estimation error, the pressure water source means can be operated at that time to reliably suppress the pad from overheating.

  FIG. 1 is an exploded longitudinal sectional view showing an embodiment of a disc brake according to the present invention. This disc brake is a vehicular disc brake having a disc in which a peripheral edge portion of a disc engaging with a pad is a double wall, and an air cooling blade row is formed between the double walls. However, the structure in this respect is already known in the art. That is, in FIG. 1, what is generally indicated by reference numeral 10 is a brake disc, and an annular peripheral portion 10c is provided alongside the peripheral portion 10b of the disc-shaped main portion 10a. The peripheral edge portion 10c is connected to the peripheral edge portion 10b by an annular blade row 10d, whereby the peripheral edge portion becomes a double wall, and a disk is formed in which an air cooling blade row is formed between the double walls. . The peripheral portions 10b and 10c are in contact with the pads 12 and 14 on their outer surfaces.

  The pad 12 is supported by a wheel suspension device 18 via a caliper 20 with a back metal 16. The pad 14 is supported by a piston 26 that slides in a wheel cylinder 24 carried by a wheel suspension 18 with a backing metal 22. The wheel suspension device 18 is a wheel suspension device for a steering wheel that is steered by a steering knuckle 28.

  The disk 10 is attached by bolts 38 to a wheel hub 36 which is rotatably supported by bearings 32 and 34 around an axle 30 carried by a wheel suspension 18 around a central hole in its main part 10a. Reference numeral 40 denotes a disk portion of the wheel attached to the wheel hub by the same bolt 38. A nut to be screwed onto the bolt 38 is omitted.

  Reference numeral 42 denotes an annular tube that operates as a means for spraying water from the radially inner side of the blade row toward the blade row, and is arranged along the radially inner side of the blade row 10d and spaced along the outer peripheral edge thereof. And a plurality of nozzle openings 44 opened toward the blade row 10d. The tube 44 is attached to the wheel suspension 18 by a plurality of stays 46 arranged along its periphery. Pressure water is sent to the pipe 44 by pressure water source means including a water storage tank 48, a pump 50, and an on-off valve 52. When the pressure water source means is operated, the nozzle opening 44 leads to the blade row 10d. Water is jetted towards. Of the pressure water source means, the water storage tank 48 and the pump 50 may be used for wipers, for example. The operations of the pump 50 and the on-off valve 52 are controlled by an electronic control unit 54 having a microcomputer.

  The electronic control unit 54 may be a vehicle centralized electronic control unit that also performs other electronic control in the vehicle, and the control of the pressure water source means may be performed as part of its control function. . Various information necessary for all the control operations is supplied to the electronic control unit 54. In particular, for the control of the pressure water source means according to the present invention, the pad 12 is used as an example. A signal indicating the pad temperature is supplied from the built-in pad temperature sensor 56, a signal indicating the vehicle speed from a vehicle speed sensor (not shown), a signal indicating depression of the brake pedal from a brake pedal switch, and a brake hydraulic pressure sensor A signal indicating the value of the hydraulic pressure supplied to the wheel cylinder 24, a signal indicating the outside air temperature from the outside air temperature sensor, a signal indicating the load on the vehicle from the load sensor, and the like may be supplied.

  The electronic control unit 54 estimates that the temperature of the pad 12 is directly based on the information obtained from these signals, and that the temperature of the pad 14 is the same as or proportional to the temperature of the pad 12 at a predetermined ratio. When the pad temperature exceeds a predetermined limit value, the pump 50 may be operated and the on-off valve 52 may be opened. However, the pad temperature may be within any outside air temperature. Therefore, it can be estimated depending on what vehicle load is loaded and how often and how much braking is applied at what speed, so the pad temperature is estimated based on the signals from various sensors as described above. When the estimated pad temperature exceeds a predetermined limit value, the pump 50 may be operated and the on-off valve 52 may be opened. In this case, the pump 50 is operated and the on-off valve 52 is opened because the pad temperature detected by the pad temperature sensor 56 exceeds a predetermined first limit value or based on the operating state of the vehicle. It may be when the estimated pad temperature exceeds a second limit value.

  In this case, if the second limit value for the estimated value based on the driving state of the vehicle is set lower than the first limit value for the measured value of the pad temperature, the pad temperature is approaching the first limit value. The state can be sensed when the estimated pad temperature reaches two lower limit values, at which point the pump 50 and on-off valve 52 are activated and the pad temperature does not approach the first limit value. Can be.

  FIG. 2 is an exploded longitudinal sectional view similar to FIG. 1 showing a disc brake according to the present invention in another embodiment. In FIG. 2, portions corresponding to the portions shown in FIG. 1 are denoted by the same reference numerals as in FIG. The disc brake shown in FIG. 2 differs from the embodiment of FIG. 1 only in that the outer race 58 of the bearing is carried by the wheel suspension 18 and the inner race 60 of the bearing constitutes a wheel hub. Since each structure in the bearing portion will be clear to those skilled in the art from the drawing, further description of the embodiment shown in FIG. 2 will be omitted to avoid redundancy of the specification.

  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.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded longitudinal sectional view showing an embodiment of a disc brake according to the present invention. FIG. 6 is an exploded longitudinal sectional view showing another embodiment of the disc brake according to the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Brake disc, 10a ... Main part of brake disc, 10b, 10c ... Peripheral part of brake disc, 10d ... Ring blade row of brake disc, 12, 14 ... Pad, 16 ... Back metal, 18 ... Wheel suspension device, 20 ... Caliper, 22 ... back metal, 24 ... wheel cylinder, 26 ... piston, 28 ... steering knuckle, 30 ... axle, 32, 34 ... bearing, 36 ... wheel hub, 38 ... bolt, 40 ... wheel disc, 42 ... annular 44 ... Nozzle opening, 46 ... Stay, 48 ... Water storage tank, 50 ... Pump, 52 ... Open / close valve, 54 ... Electronic controller, 56 ... Pad temperature sensor, 58 ... Outer race, 60 ... Inner race

Claims (6)

  A disk brake for a vehicle having a disk in which a peripheral edge portion of a disk engaging with a pad is formed as a double wall and an air cooling blade array is formed between the double walls, from the radially inner side of the blade array. A disc brake comprising means for injecting water toward the blade row.   The water spraying means is disposed along the radially inner side of the blade row and is spaced along the outer peripheral edge thereof, and has an annular tube having a plurality of nozzle openings opened toward the blade row, and into the tube. The disc brake according to claim 1, further comprising pressure water source means for pumping water.   3. The vehicle disc brake according to claim 2, wherein the pressure water source means is operated when the temperature of the pad exceeds a predetermined limit value.   The disc brake is for a vehicle, and the pressure water source means is activated when a temperature of the pad estimated based on a driving state of the vehicle exceeds a predetermined limit value. Item 3. The disc brake according to item 2.   The disc brake is for a vehicle, and the pressure water source means determines whether the pad temperature exceeds a first limit value or whether the pad temperature estimated based on the driving state of the vehicle exceeds a second limit value. The disc brake according to claim 2, wherein the disc brake is operated when at least one of the following occurs.   6. The disc brake according to claim 5, wherein the second limit value is set lower than the first limit value.

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