JP2006161826A - Disc brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow smooth slide travel of a floating type caliper for a mounting and suppress squeak noise of brake by restraining the floating type caliper for the mounting as required. <P>SOLUTION: This disc brake device 1 generates braking force by pressing an inner pad 6 and an outer pad 8 on a brake disc 4 by the floating type caliper 2, which is slidably supported on the mounting 20 through a slide pin 22 inserted into a hole part 20a formed in the mounting 20. Electric viscous fluid ER is sealed in each hole part 20a of the mounting 20, and electric field is given to the electric viscous fluid ER when, for example, falling-down of the brake disc 4 is increased to some extent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a disc brake device, and more particularly to a disc brake device that generates a braking force by pressing a pad against a brake disc by a floating caliper supported by a mounting.

Conventionally, as a brake caliper of a disc brake device applied to a vehicle, a hydraulic unit for pressing a pad is included, and a mounting (torque member) fixed to a vehicle body is slidable via a slide pin. A supported floating caliper is known (see, for example, Patent Document 1). This floating caliper has a caliper body that holds a pair of pads, and a slide pin is fixed to a pin fixing portion of the caliper body. The slide pin is inserted into a slide hole formed in the mounting, whereby the floating caliper is slidable in the axial direction of the brake disc with respect to the mounting.
JP 2003-120725 A

  In the above-described floating caliper, in order to maintain good productivity, allow the caliper to move smoothly with respect to the mounting, and suppress the occurrence of vibration, the gap between the mounting hole and the slide pin is required. It is necessary to secure a certain amount of clearance. For this reason, when the brake disc is dynamically tilted with respect to the axial direction when the vehicle is turning, or when uneven wear occurs in the pad diameter method, the slide pin tilts in the mounting hole and slides. The contact area between the pin and the inner surface of the hole in the mounting may be reduced, which may cause the floating caliper to become unconstrained by the mounting and cause a brake squeal.

  Accordingly, the present invention provides a disc brake device that allows smooth sliding movement of the floating caliper relative to the mounting, and restrains the occurrence of squealing by restraining the floating caliper with respect to the mounting as necessary. With the goal.

  A disc brake device according to the present invention is a disc brake device that generates a braking force by pressing a pad against a brake disc by a floating caliper supported by the mounting. The floating caliper is inserted into a hole formed in the mounting. It is characterized by being supported so as to be slidable with respect to the mounting via a slide pin, and an electrorheological fluid is sealed in the hole of the mounting.

  In this disc brake device, an electrorheological fluid that normally has a low viscosity but can increase the viscosity by applying an electric field is enclosed in a mounting hole into which the slide pin is inserted. Therefore, if an electric field is not applied to the electrorheological fluid, the viscosity of the electrorheological fluid is kept low, so that the slide pin can move smoothly in the hole, and the smooth movement of the floating caliper relative to the mounting can be prevented. Permissible. On the other hand, when the brake disc falls over in the axial direction during turning of the vehicle, or when the pad wears unevenly, an electric field is applied to the electrorheological fluid. By increasing the viscosity of the electrorheological fluid, the inclination of the slide pin in the mounting hole can be suppressed. As a result, the floating caliper can be restrained against the mounting to suppress the occurrence of brake squeal.

  In addition, the disc brake device according to the present invention includes an electric field applying unit that applies an electric field to the electrorheological fluid, a disc falling acquisition unit that acquires a degree of tilting of the brake disc, and a brake disc acquired by the disc falling acquisition unit. It is preferable to further comprise control means for applying an electric field to the electrorheological fluid by the electric field applying means based on the degree of collapse.

  Under such a configuration, an electric field is applied to the electrorheological fluid when the brake disc tilts to a certain extent, thereby restraining the floating caliper against the mounting and generating good brake noise. Can be suppressed.

  Furthermore, the disc brake device according to the present invention includes an electric field applying unit that applies an electric field to the electrorheological fluid, a load detecting unit that detects a load applied to the slide pin, and an electric field applying unit based on a detection value of the load detecting unit. Control means for applying an electric field to the electrorheological fluid may be further provided.

  When the slide pin is inclined in the mounting hole, the contact area between the slide pin and the inner surface of the mounting hole is reduced, so that the load applied to the slide pin from the mounting is reduced. Therefore, even if the load applied to the slide pin is detected by the load detecting means and the electric field is applied to the electrorheological fluid by the electric field applying means based on the detection result, the floating caliper is restrained against the mounting. Therefore, it is possible to satisfactorily suppress the occurrence of brake squeal.

  Another disc brake device according to the present invention is a disc brake device that generates a braking force by pressing a pad against a brake disc by a floating caliper supported by the mounting. The floating caliper is formed in a hole formed in the mounting. It is slidably supported with respect to the mounting via a slide pin to be inserted, and a magnetorheological fluid is sealed in the hole of the mounting.

  Like this disc brake device, the electrorheological fluid was used even when enclosing a magnetorheological fluid that normally has a low viscosity in the mounting hole but can increase the viscosity by applying a magnetic field. The same effect as in the case can be obtained.

  According to the present invention, it is possible to allow a smooth sliding movement of the floating caliper with respect to the mounting, and restrain the floating caliper with respect to the mounting as necessary to suppress the occurrence of squealing of the brake.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a partial sectional view showing a main part of a disc brake device according to the present invention. A disc brake device 1 shown in the figure is applied to a vehicle such as an automobile, and generates an braking force by pressing an inner pad 6 and an outer pad 8 against a brake disc 4 attached to a wheel (not shown) by a floating caliper 2. Is.

  The floating caliper 2 has a caliper body 10 that holds the inner pad 6 and the outer pad 8, and the brake disk 4 is disposed between the inner pad 6 and the outer pad 8. The caliper body 10 includes a hydraulic unit 16 including a cylinder 12 and a piston 14. When the driver operates the brake pedal, hydraulic fluid is supplied to the cylinder 12, whereby the piston 14 moves forward and backward within the cylinder 12. The inner pad 6 described above is fixed to the tip of the piston 14, and the outer pad 8 is fixed to the caliper body 10 so as to face the inner pad 6.

  The floating caliper 2 having such a configuration is slidably supported via a slide pin 22 with respect to a metal mounting 20 fixed to the vehicle body of the vehicle. In other words, the caliper body 10 of the floating caliper 2 is formed with pin fixing portions 10a at two positions spaced apart from each other, and the slide pin 22 is fixed to each pin fixing portion 10a. The mounting 20 is formed with two holes 20 a extending in the axial direction of the brake disc 4 so as to correspond to the pin fixing portions 10 a of the caliper body 10. A slide pin 22 fixed to the caliper body 10 is inserted into each hole 20 a of the mounting 20, whereby the caliper body 10 is slidable in the axial direction of the brake disc 4 with respect to the mounting 20. In addition, a boot 24 is installed between each pin fixing portion 10a and the mounting 20 to prevent foreign matters from entering the hole 20a. The boot 24 is made of an elastic body such as rubber, and can be expanded and contracted at least in the axial direction of the brake disc 4.

  When a wheel (not shown) is braked by the disc brake device 1 as described above, the piston 14 is moved toward the outer pad 8 by the hydraulic fluid introduced into the cylinder 12, thereby causing the piston 14 to move. The fixed inner pad 6 is pressed against the brake disc 4. At this time, the caliper body 10 slides in a direction from the outer pad 8 toward the inner pad 6 in FIG. 1 by a reaction force when the inner pad 6 is pressed against the brake disk 4. As a result, the outer pad 8 is also pressed against the brake disc 4, and braking force is applied to a wheel (not shown) via the brake disc 4.

  Here, in the floating caliper 2 as described above, in order to maintain good productivity, to allow smooth sliding movement of the caliper body 10 with respect to the mounting 20, and to suppress the occurrence of vibration, FIG. As shown in FIG. 2, it is necessary to secure a clearance of, for example, about 0.1 to 0.5 mm between the inner surface of the hole 20a and the slide pin 22. Even if the clearance between the hole 20a and the slide pin 22 is provided as described above, normally, as shown in FIG. 1, one slide pin 22 (the lower side in the figure) has a hole along its entire length. By making contact with the inner surface of the portion 20a, the other slide pin 22 also extends substantially coaxially with the hole 20a inside the corresponding hole 20a.

  On the other hand, the brake disk 4 may be dynamically tilted with respect to the axial direction during turning of the vehicle or the like, and uneven wear in the diameter method of the inner pad 6 or the outer pad 8 may occur. In such a case, if no measures are taken, the slide pin 22 tilts in the hole 20a, thereby reducing the contact area between the slide pin 22 and the inner surface of the hole 20a. There is a possibility that the brakes may be generated because the mounting 20 is not restrained.

  In view of such a point, in the disc brake device 1 of the present embodiment, each hole 20a of the mounting 20 into which the slide pin 22 is inserted normally has a low viscosity, while applying an electric field to the viscosity. The electrorheological fluid ER that can increase the flow rate is enclosed. The electrorheological fluid ER may be a base oil mixed with fine particles or a single substance. In addition, the outflow of the electrorheological fluid ER to the outside is prevented by the boot 24 provided between each pin fixing portion 10a and the mounting 20. As shown in FIG. 2, a power source 28 as an electric field applying means is connected to the mounting 20 and each slide pin 22 via a switch 26. By turning on the switch 26, the hole 20a is turned on. An electric field can be applied to the electrorheological fluid ER inside.

  As shown in FIG. 2, the switch 26 is connected to a brake ECU 30 that functions as a control unit of the disc brake device 1, and is ON / OFF controlled by the brake ECU 30. The brake ECU 30 includes a CPU, a ROM, a RAM, an input / output port, a storage device, and the like (not shown). The brake ECU 30 is connected to a steering angle sensor 32 provided in a vehicle steering mechanism. The steering angle sensor 32 detects the steering angle of the front wheels and gives a signal indicating the detected value to the brake ECU 30.

  Next, a procedure for applying an electric field to the electrorheological fluid ER sealed in the hole 20a of the mounting 20 will be described with reference to FIG.

  The routine shown in FIG. 3 is repeatedly executed by the brake ECU 30 every predetermined time. When the execution timing of the routine in FIG. 3 is reached, the brake ECU 30 acquires the steering angle of the front wheels of the vehicle based on the signal from the steering angle sensor (S10). When the steering angle of the front wheels is acquired in S10, the brake ECU 30 determines whether or not the acquired steering angle is equal to or greater than a predetermined threshold (S12). The threshold value used in S12 is a correlation between the steering angle of the front wheel and the degree of tilt of the brake disk 4 that is experimentally and empirically determined, and the degree of tilt of the brake disk 4 that is also experimentally and empirically determined. It is determined based on the correlation with the occurrence frequency of brake squeal. That is, in S10 and S12, the degree of tilting of the brake disk 4 is substantially acquired, and the magnitude of the degree of tilting of the brake disk 4 is determined.

  If it is determined in S12 that the steering angle of the front wheels is equal to or greater than a predetermined threshold (Yes in S12), the brake ECU 30 turns on the switch 26 so that an electric field is applied to the electrorheological fluid ER by the power supply 28. (S14). As described above, in the disc brake device 1, when it is determined that the dynamic tilt in the axial direction of the brake disc 4 has increased to some extent due to turning of the vehicle or the like, the electrorheological fluid ER in each hole 20a. An electric field is applied to the electrorheological fluid ER, and the viscosity of the electrorheological fluid ER is increased. As a result, the inclination of the slide pin 22 in the hole 20a of the mounting 20 can be suppressed, that is, the geometric change between the floating caliper 2 and the mounting 20 can be suppressed. Therefore, it is possible to restrain the occurrence of brake squeezing favorably.

  On the other hand, when the steering angle of the front wheels is below a predetermined threshold value in S12 and it is determined that there is little dynamic tilting in the axial direction of the brake disc 4 (No in S12), the brake ECU 30 switches to the switch 26. Is turned off so that the electric field is not applied to the electrorheological fluid ER by the power source 28 (S16). Thus, if an electric field is not applied to the electrorheological fluid ER, the viscosity of the electrorheological fluid ER is kept low, so that each slide pin 22 can move smoothly in the hole 20a and Smooth sliding movement of the floating caliper 2 is allowed. After executing the processing of S14 and S16, the brake ECU 30 executes the routine of FIG. 3 again at the next execution timing.

  FIG. 4 is a timing chart for explaining another example of a procedure for applying an electric field to the electrorheological fluid ER sealed in the hole 20a of the mounting 20.

  As described above, each slide pin 22 basically extends coaxially within the hole 20a unless the brake disk 4 is tilted or the inner pad 6 or the outer pad 8 is worn unevenly. Therefore, the contact area between each slide pin 22 and the inner surface of the hole 20a is maintained to some extent, and a certain amount of load (stress) is applied to each slide pin 22 from the mounting 20.

  On the other hand, if the slide pin 22 tilts in the hole 20a of the mounting 20 at a certain timing due to the fall of the brake disk 4 or uneven wear of the inner pad 6 or the outer pad 8, the mounting with the slide pin 22 Since the contact area with the inner surface of the 20 holes 20a is reduced, the load applied from the mounting 20 to the slide pin 22 becomes extremely small as shown in FIG. Accordingly, as indicated by a two-dot chain line in FIG. 1, a load (stress) applied to the slide pin 22 is detected using a load sensor 34 such as a strain gauge provided on any or all of the slide pins 22. Then, the switch 26 may be turned on based on the detection result, and an electric field may be applied to the electrorheological fluid ER by the power source 28.

  Here, when the slide pin 22 is tilted, the contact between the vicinity of the root portion of the slide pin 22 and the inner surface of the hole 20a is basically cut off. It is good to be attached to. When such a load sensor 34 is used, the load (stress) applied to any or all of the slide pins 22 is acquired based on the signal from the load sensor 34 in S10 of FIG. It may be determined whether or not the load applied to the slide pin 22 has become a predetermined threshold value or less. When the load applied to the slide pin 22 falls below a predetermined threshold value, the switch 26 is turned on, and an electric field is applied to the electrorheological fluid ER by the power source 28. Even if such a procedure is adopted, the inclination of the slide pin 22 in the hole 20a of the mounting 20 can be suppressed, that is, the geometric change between the floating caliper 2 and the mounting 20 can be suppressed. The caliper 2 can be restrained with respect to the mounting 20 and the occurrence of brake squeal can be satisfactorily suppressed.

  In addition, although the above-mentioned disc brake apparatus 1 was demonstrated as what the electrorheological fluid ER was enclosed in each hole 20a of the mounting 20, it is not restricted to this. That is, in the disc brake device 1, even if a magnetorheological fluid that normally has a low viscosity and can be increased in viscosity by applying a magnetic field is sealed in each hole 20 a of the mounting 20, An effect similar to that obtained when the fluid ER is used can be obtained.

It is a fragmentary sectional view which shows the principal part of the disc brake device by this invention. FIG. 2 is a control block diagram of the disc brake device of FIG. 1. It is a flowchart for demonstrating the procedure which provides an electric field to the electrorheological fluid enclosed in the hole of the mounting contained in the disc brake apparatus of FIG. FIG. 6 is a timing chart for explaining another example of a procedure for applying an electric field to the electrorheological fluid sealed in the mounting hole included in the disc brake device of FIG. 1.

Explanation of symbols

1 disc brake device, 2 floating caliper, 4 brake disc, 6 inner pad, 8 outer pad, 10 caliper body, 10a pin fixing part, 12 cylinder, 14 piston, 16 hydraulic unit, 20 mounting, 20a hole, 22 Slide pin, 24 boot, 26 switch, 28 power supply, 30 brake ECU, 32 rudder angle sensor, 34 load sensor, ER electrorheological fluid

Claims (4)

In a disc brake device that generates a braking force by pressing a pad against a brake disc by a floating caliper supported by the mounting,
The floating caliper is slidably supported with respect to the mounting via a slide pin inserted into a hole formed in the mounting, and an electrorheological fluid is enclosed in the hole of the mounting. Disc brake device characterized by being made. An electric field applying means for applying an electric field to the electrorheological fluid;
A disc fall acquisition means for obtaining the degree of fall of the brake disc;
2. The control unit according to claim 1, further comprising a control unit configured to apply an electric field to the electrorheological fluid by the electric field applying unit based on a degree of tilting of the brake disk acquired by the disc falling acquiring unit. Disc brake device as described. An electric field applying means for applying an electric field to the electrorheological fluid;
Load detecting means for detecting a load applied to the slide pin;
The disc brake device according to claim 1, further comprising a control unit configured to apply an electric field to the electrorheological fluid by the electric field applying unit based on a detection value of the load detecting unit. In a disc brake device that generates a braking force by pressing a pad against a brake disc by a floating caliper supported by the mounting,
The floating caliper is slidably supported with respect to the mounting via a slide pin inserted into a hole formed in the mounting, and a magnetorheological fluid is enclosed in the hole of the mounting. Disc brake device characterized by being made.

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