Brake system

Abstract

To provide a braking system that can suppress the occurrence of brake judder. [Solution] The brake device 10 includes a brake pad 14 positioned opposite the disc rotor, a torque member 11 fixed to the vehicle body and supporting the brake pad 14 so that it can move back and forth in the axial direction of the disc rotor, and a cylinder body 12 slidably supported by the torque member 11 along the axial direction of the disc rotor and generating a pressing force that presses the brake pad 14 against the disc rotor. The torque member 11 is equipped with a retainer 20 having a leaf spring portion 25, and the leaf spring portion 25 applies a load to the cylinder body 12 in the direction of rotation of the disc rotor.

Description

Technical Field

[0001] The present invention relates to a braking device.

Background Art

[0002] Conventionally, a disc brake device is known in which an inner pad presses a disc by the forward movement of a piston of a cylinder, and as a result, a caliper retreats and an outer pad is pressed against the disc, and braking force is obtained by sandwiching the disc between the inner pad and the outer pad (for example, Patent Document 1). In this Patent Document 1, a pair of bolts attached to a non-rotating part of a vehicle are fitted into a sleeve, and a slide part of a caliper is supported by the sleeve so as to be displaceable. A rubber boot is provided on a sliding part of the sleeve and the slide part, and when the caliper is tilted by a moment force acting on the caliper, the base part of the boot is pressed to accumulate a spring force (reaction force), and when the brake is released, the reaction force returns the posture of the caliper so that the sleeve and the slide part become parallel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, during light braking, brake judder may occur due to the inclination of the caliper. In particular, in recent years, an actuator for an electronic parking brake may be provided in a cylinder body, and in this case, the center of gravity of the caliper is separated from the surface of the brake rotor, so that the possibility of occurrence of the above-mentioned brake judder becomes high.

[0005] The present invention aims to provide a braking device capable of suppressing the occurrence of brake judder. [Means for solving the problem]

[0006] A brake device according to one aspect of the present disclosure comprises a brake pad positioned opposite a disc rotor, a torque member fixed to the vehicle body and supporting the brake pad so as to be able to move back and forth in the axial direction of the disc rotor, and a cylinder body slidably supported by the torque member along the axial direction of the disc rotor and generating a pressing force to press the brake pad against the disc rotor. The torque member is further provided with a load application section that applies a load to the cylinder body in the direction of rotation of the disc rotor.

[0007] This allows a load to be applied to the cylinder body along the rotational direction of the disc rotor, so that even if a moment force acts on the cylinder body, the load applied by the load application part can return the cylinder body to its original position. This suppresses the occurrence of brake judder caused by the tilting of the cylinder body. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic diagram of a brake device in one embodiment of the present disclosure, viewed from the outer circumference of the disc rotor. [Figure 2] A schematic diagram of the brake device of this embodiment, viewed from the side indicated by arrow a in Figure 1. [Figure 3] A schematic diagram of the brake device of this embodiment, viewed from the side indicated by arrow B in Figure 1. [Figure 4] An enlarged perspective view of the retainer of this embodiment. [Figure 5] A diagram illustrating the braking operation of the brake system. [Figure 6] This diagram shows the center of gravity of the cylinder body and the moment force acting on the cylinder body. (A) shows the case where an actuator is not provided on the cylinder body, and (B) shows the case where an actuator is provided on the cylinder body. [Figure 7]A force balance diagram of the braking device with respect to moment force in this embodiment. [Figure 8] A perspective view showing an example of a retainer according to Modification 1. [Figure 9] A schematic diagram of the brake system when using the retainer shown in Figure 8, viewed from the side indicated by arrow B in Figure 1. [Modes for carrying out the invention]

[0009] Hereinafter, a disc brake device (hereinafter simply referred to as the brake device) according to one embodiment of the present disclosure will be described. Figure 1 is a schematic diagram of the brake device 10 of this embodiment as seen from the outer circumference side of the disc rotor. Figure 2 is a schematic diagram of the brake device 10 of Figure 1 as seen from the side of arrow a. In the following explanation, the direction in which the disc rotor axis parallel to the rotation axis P0 of the wheel 1 is axially determined as direction P1. The brake device 10 is positioned to sandwich the disc rotor 2, which rotates coaxially with the wheel 1, in the direction P1.

[0010] The brake device 10 comprises a torque member 11, a cylinder body 12, a slide pin 13, and a brake pad 14. The torque member 11 is fixed to a wheel support member (vehicle body side member) (not shown) and is positioned opposite the disc rotor 2 to position a brake pad 14 that can contact the disc rotor 2. A cylinder body 12 is also supported on the torque member 11 via a pair of slide pins 13 so as to be slidable in the P1 direction.

[0011] The cylinder body 12 is positioned to straddle the disc rotor 2 in the P1 direction, and as shown in Figure 2, the claw portion 12A and the base portion 12B are arranged to face each other in the P1 direction with the disc rotor 2 in between. The base portion 12B is provided with a cylinder bore 12C whose axis is in the P1 direction, and a piston 15, which is positioned coaxially with the cylinder bore 12C, is arranged to move back and forth in the P1 direction in accordance with the hydraulic fluid supplied to and discharged from the cylinder bore 12C. Furthermore, a seal ring 16 is positioned between the piston 15 and the cylinder bore 12C, and when braking, it elastically deforms, causing the piston 15 to retract by a certain distance when the brake is released.

[0012] Here, the pressing means is composed of a cylinder body 12 equipped with the claw portion 12A, a piston 15, and a cylinder bore 12C. Furthermore, a pair of brake pads 14 are positioned opposite each other between the piston 15 and the claw portion 12A of the cylinder body 12, with the disc rotor 2 in between. Each brake pad 14 consists of a backing plate 14A that is pressed by the claw portion 12A or the piston 15, and a friction material 14B that is fixed to the backing plate 14A and faces the friction sliding surface 2A of the disc rotor 2.

[0013] Figure 3 is a schematic diagram of the brake device 10 as seen from the direction of arrow B in Figure 1. In Figure 3, the direction of P1 is not shown, but the direction perpendicular to the plane of the paper in the figure is the direction of P1. The brake pad 14 is supported on the torque member 11 via a retainer 20 so as to be slidable in the P1 direction. In Figure 3, the direction of forward and reverse rotation of the disc rotor 2 at the position where the brake pad 14 is positioned, which is parallel to the friction sliding surface 2A of the disc rotor 2, is defined as the P2 direction, the forward rotation direction of the disc rotor 2 when the vehicle is moving forward is defined as the +P2 side, and the reverse rotation direction is defined as the -P2 side. The brake pad 14 has ear portions 14D formed on the ±P2 side end faces (circumferential end faces 14C) that protrude toward the torque receiving surface 11A of the opposing torque member 11. The ear portions 14D can be loosely fitted into recesses 11B formed on the torque receiving surface 11A side, thereby restricting the movement of the brake pad 14 in the P1 direction.

[0014] Figure 4 is an enlarged perspective view of the retainer 20. The retainers 20 are provided on the torque receiving surfaces 11A (only the +P2 side is shown in Figure 3) of the torque member 11 that face each other in the P2 direction, and hold the brake pad 14 as described above. Specifically, the retainer 20 includes a concave fitting portion 21 that engages with the concave portion 11B of the torque member 11, and a plurality of locking portions 22 that lock the retainer 20 to the torque member 11. When the fitting portion 21 is fitted into the concave portion 11B and the locking portions 22 are engaged with predetermined engaging portions provided on the torque member 11, the retainer 20 is fixed to the torque member 11. A leaf spring-like retainer spring 23 is provided on the fitting portion 21 of the retainer 20. The retainer spring 23 holds the ear portion 14D of the brake pad 14 and biases the brake pad 14 in a direction away from the disc rotor 2. The retainer 20 further includes a pad holding portion 24 that extends toward the inner peripheral side of the disc rotor 2. The pad holding portion 24 is locked to a part of the axial end face 14E that intersects the circumferential end face 14C of the brake pad 14. This prevents the brake pad 14 from rattling.

[0015] Furthermore, the retainer 20 includes a leaf spring portion 25 that extends toward the outer surface portion 12D that intersects the P2 direction of the cylinder body 12 and is capable of abutting against the cylinder body 12. In the present embodiment, as shown in FIGS. 3 and 4, the leaf spring portion 25 is provided on the side opposite to the pad holding portion 24 with the fitting portion 21 interposed therebetween. When the brake pad 14 and the disc rotor 2 come into contact during braking and a moment force is applied to the cylinder body 12 causing it to tilt, the leaf spring portion 25 applies a load (biasing force) against the moment force to the cylinder body 12. This suppresses the tilt of the cylinder body 12 due to the moment force.

[0016] Next, the operation and the like of the brake device 10 will be described based on FIG. 5. FIG. 5 is a diagram showing the braking operation of the brake device 10. As shown in Figure 5(A), in the non-braking state, the brake pads 14 are elastically held by the torque member 11 with their oscillation suppressed by the retainer 20 (not shown in Figure 5). When braking is applied from this state, as shown in Figure 5(B), each brake pad 14 is pressed against the claw portion 12A of the cylinder body 12 and the piston 15, contacting and clamping the disc rotor 2. At this time, as shown in Figure 5(C), the brake pads 14 receive a force F in the rotational direction of the disc rotor 2, causing the torque member 11 to tilt according to the rotational direction of the disc rotor 2, and causing a shift in the sliding amounts La and Lb of the pair of slide pins 13. In addition, the cylinder body 12 that holds the piston 15 that presses the brake pads 14 also tilts due to the moment force M caused by the rotational direction of the disc rotor 2. Furthermore, as the wheels are braked, a force F' acts to correct the tilt of the torque member 11, as shown in Figure 5(D), which also causes the sliding amounts La and Lb of the pair of slide pins 13 to be equal. As shown in Figure 5(E), the torque member 11 returns to its normal position. In addition, the pressing force that presses the brake pads 14 against the disc rotor 2 is released, so as shown in Figure 5(F), the position of the cylinder body 12 also returns to normal, and each brake pad 14 separates from the disc rotor 2.

[0017] By the way, by providing other components to the cylinder body 12, such as an actuator for an electronic parking brake, the center of gravity of the cylinder body 12 moves to a position away from the disc rotor 2. In this case, as shown in Figure 5(C), the moment force M acting on the cylinder body 12 increases. Alternatively, if the cylinder body 12 is made of a lightweight material such as aluminum in order to reduce the weight of the brake caliper, the effect of the moment force M acting on the cylinder body 12 will also increase. Figures 6(A) and 6(B) show the center of gravity of the cylinder body 12 and the moment force acting on the cylinder body 12. Figure 6(A) shows the center of gravity position G1 of the cylinder body 12 and the moment force M1 acting on the cylinder body 12 when no actuator is provided, and Figure 6(B) shows the center of gravity position G2 of the cylinder body 12 and the moment force M2 acting on the cylinder body 12 when an actuator 30 is provided on the cylinder body 12.

[0018] Typically, as shown in Figure 6(A), the center of gravity position G1 of the cylinder body 12 is designed to fall within the range Sg so that it does not overhang the fitting position 13A of the slide pin 13 to the torque member 11. This helps to suppress damage to the cylinder of the cylinder body 12. Furthermore, the moment force M that the cylinder body 12 receives when the brake pad 14 contacts the disc rotor 2 is the distance from the contact surface position H1 between the brake pad 14 and the piston 15 to the fitting position 13A of the slide pin 13 (moment arm L M It depends on the moment arm, and the larger the moment arm, the larger the moment force. In the case where the actuator 30 is not provided on the cylinder body 12, as shown in Figure 6(A), the center of gravity G1 is close to the disc rotor 2, and the fitting position 13A of the slide pin 13 can also be designed to be close to the disc rotor 2. Therefore, the moment force M1 acting on the cylinder body 12 is also relatively small.

[0019] On the other hand, as shown in Figure 6(B), when the actuator 30 is attached to the cylinder body 12, the center of gravity G2 of the cylinder body 12 is located further away from the disc rotor 2 than when the actuator 30 is not provided. Therefore, the fitting position 13A of the slide pin 13 also needs to be designed to be located further away from the disc rotor 2. In this case, moment arm L M As the magnitude increases, the cylinder body 12 receives a larger moment force M2 compared to the case in Figure 6(A). In this case, the increased inclination of the cylinder body 12 causes the surface of the piston 15 that contacts the brake pad 14 during braking to tilt, resulting in brake judder.

[0020] Figure 7 is a force balance diagram of the brake device 10 with respect to the moment force M2 in this embodiment. In this embodiment, as described above, the retainer 20 is provided with a leaf spring portion 25 that can contact the cylinder body 12. In this case, as shown in Figure 7, the brake pad 14 receives a reaction force W1 of the spring force of the retainer spring 23 of the retainer 20. In addition, the cylinder body 12 is subjected to a reaction force W2 of the spring force of the leaf spring portion 25 that opposes the moment force M2. In other words, by the cylinder body 12 pressing against the leaf spring portion 25, a load opposite to the direction of the moment force M2 is applied to the cylinder body 12, biasing the cylinder body 12 to return to its original position and suppressing the tilting of the cylinder body 12.

[0021] As shown in Figure 5(C), the cylinder body 12 tilts due to the moment force M2 when the vehicle is moving forward. During braking when the vehicle is moving backward, the wheel rotation speed is slow, and the effect of the moment force M2 is extremely small. Therefore, the leaf spring portion 25 on the retainer 20 only needs to be positioned to resist the moment force M2 at least when the vehicle is moving forward (forward rotation). In this embodiment, a leaf spring portion 25 is provided on the retainer 20 that positions the brake pad 14. Therefore, it is sufficient to provide the leaf spring portion 25 on the retainer 20 at least at the entry position for forward rotation, and it is not necessary to provide the leaf spring portion 25 at the exit position.

[0022] [Effects of this embodiment] The brake device 10 of this embodiment includes a brake pad 14 positioned opposite to a disc rotor 2 that rotates with the wheel, a torque member 11 fixed to the vehicle body and supporting the brake pad 14 so as to be able to move back and forth in the P1 direction of the disc rotor 2, a cylinder body 12 slidably supported by the torque member 11 along the P1 direction of the disc rotor 2 and generating a pressing force to press the brake pad 14 against the disc rotor 2, and a retainer 20 (load application part) provided on the torque member 11 and having a leaf spring portion 25 that applies a load to the cylinder body 12 in the direction of rotation of the disc rotor 2. With this configuration, even when a moment force M2 corresponding to the rotation direction of the disc rotor 2 is applied to the cylinder body 12, the leaf spring portion 25 provided on the retainer 20 applies a load that resists the moment force M2, thereby suppressing the tilting of the cylinder body 12 and suppressing the occurrence of brake judder. In particular, when an actuator for an electronic parking brake or the like is attached to the cylinder body 12 and the center of gravity position G2 of the cylinder body 12 is located away from the disc rotor 2, the moment force M2 acting on the cylinder body 12 becomes large. In this embodiment, even when such a large moment force M2 is applied, the tilting of the cylinder body 12 can be suppressed, and the occurrence of brake judder can be effectively suppressed.

[0023] In the brake device 10 of this embodiment, the leaf spring portion 25 applies a load in a direction that opposes the moment force M2 received when the brake pad 14 is pressed against the disc rotor 2 when the vehicle is moving forward. In other words, by positioning the leaf spring portion 25 of the retainer 20 at least at the entry position in the rotational direction of the disc rotor 2, it is possible to effectively suppress tilting of the cylinder body 12 and the resulting brake judder in response to the larger moment force M2 applied to the cylinder body 12 when the vehicle performs a braking operation while moving forward.

[0024] The brake device 10 of this embodiment includes a retainer 20 provided on the torque member 11 for positioning the brake pad 14. The retainer 20 includes a fitting portion 21 fixed to the torque member 11 and a leaf spring portion 25 extending in a predetermined direction from the fitting portion 21 and capable of contacting the cylinder body 12. The leaf spring portion 25 functions as the load application portion of this disclosure. This allows the retainer 20 that holds the brake pad 14 in the torque member 11 to function as a load application part, thereby reducing the cost of the brake device 10 compared to when other components are added to the cylinder body 12.

[0025] [Differentiation] The present invention is not limited to the embodiments described above, but also includes the following modifications to the extent that the objectives of the present invention can be achieved.

[0026] [Example 1] For example, in the above embodiment, the leaf spring portion 25, which functions as a load application portion, is configured to extend toward the cylinder body 12 from the end of the retainer 20 opposite to the pad holding portion 24, but the position of the leaf spring portion 25 is not limited to this.

[0027] Figure 8 is a perspective view showing another example of the retainer 20A, and Figure 9 is a schematic view of the brake device 10 when using the retainer 20A of Figure 8, viewed from the direction of arrow B along the P1 direction. In the examples shown in Figures 8 and 9, the retainer 20A includes a fitting portion 21, a locking portion 22, a retainer spring 23, and a pad holding portion 24, similar to the embodiment described above. In addition, in the retainer 20A of this example, the leaf spring portion 25 is provided between the pad holding portion 24 and the fitting portion 21, and is capable of contacting the outer surface portion 12D of the cylinder body 12. Even when using such a retainer 20A, as in the above embodiment, even if a moment force M that causes the cylinder body 12 to tilt is generated when the brake pad 14 and the disc rotor 2 come into contact during braking, a load that resists that moment force can be applied to the cylinder body 12, thereby suppressing the tilting of the cylinder body 12.

[0028] [Differentiation 2] In the above embodiment, a configuration in which the retainer 20 has a leaf spring portion 25 as a load-applying portion was illustrated, but a configuration in which a member different from the retainer 20 is provided on the torque member 11 as a load-applying portion is also possible. For example, a biasing member that functions as a load application part may be fixed to the torque member 11 at a position different from the retainer 20, thereby applying a load to the cylinder body 12 that resists the moment force M2 applied to the cylinder body 12. As the biasing member, for example, a leaf spring, a coil spring, an elastic member, etc., can be used.

[0029] Furthermore, while the above embodiment exemplified a leaf spring section 25 as the load application section, which uses the reaction force when the cylinder body 12 is compressed due to its inclination as the load, the invention is not limited to this. For example, the load application section may be one that receives tensile stress due to the inclination of the cylinder body 12 and applies that reaction force to the cylinder body 12. In this case, the load application section is made of an elastic material such as rubber, a tensile spring, etc., and the torque member 11, the cylinder body 12, and the load application section are connected. As a result, the load application section receives tensile stress due to the inclination of the cylinder body 12, and that reaction force can be applied to the cylinder body 12 as a load. [Explanation of Symbols]

[0030] 2...Disc rotor, 10...Brake device, 11...Torque member, 12...Cylinder body, 12D...Outer surface, 13...Slide pin, 14...Brake pad, 15...Piston, 20,20A...Retainer, 25...Leaf spring part (load application part), 30...Actuator.

Claims

1. Brake pads positioned opposite the disc rotor that rotates with the wheel, A torque member fixed to the vehicle body and supporting the brake pad so that it can move back and forth in the axial direction of the disc rotor, A cylinder body is slidably supported on the torque member along the axial direction of the disc rotor and generates a pressing force that presses the brake pad against the disc rotor, A load application unit is provided on the torque member for applying a load to the cylinder body in the direction of rotation of the disc rotor, A braking device equipped with a brake system.

2. The load application unit applies the load in a direction that opposes the moment force received when the brake pad is pressed against the disc rotor during forward movement of the vehicle. The brake device according to claim 1.

3. The torque member is provided with a retainer for positioning the brake pad, The retainer comprises a fixing portion fixed to the torque member and a leaf spring portion extending in a predetermined direction from the fixing portion and capable of contacting the cylinder body. The load application section is composed of the leaf spring section. The brake device according to claim 1.

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