Braking device

Abstract

Regarding the braking system, the distribution of braking force in the longitudinal direction of the vehicle will be improved. [Solution] The disclosed braking device 4 comprises a brake disc 6, a caliper 7, and a reverse rotation mechanism 10. The brake disc 6 is formed in a disc shape and is mounted coaxially with the axle 5. The caliper 7 generates braking force by applying a pressing force to the brake disc 6. The reverse rotation mechanism 10 is interposed between the axle 5 and the brake disc 6 and rotates the brake disc 6 in the opposite direction to the axle 5.

Description

[Technical Field]

[0001] This matter concerns a braking device for braking the wheels of a vehicle. [Background technology]

[0002] One type of braking device installed in vehicles is the disc brake system. A disc brake system generates braking force by clamping a disc-shaped brake disc (rotating friction member), which is fixed to the axle, between brake pads on both sides of the disc surface. The brake disc is installed to rotate integrally with the tire and wheel (see Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2013-082321 [Overview of the project] [Problems that the invention aims to solve]

[0004] During vehicle braking, the distribution of braking force in the longitudinal direction fluctuates significantly due to weight transfer. This means that, for example, the front wheels require brakes with greater effectiveness and heat capacity than the rear wheels. Furthermore, the rear wheels are more prone to weight loss, which can lead to unstable vehicle behavior.

[0005] One of the objectives of this invention is to provide a braking device that was devised in light of the above-mentioned problems and that can improve the distribution of braking force in the longitudinal direction of a vehicle. In addition to this objective, other objectives of this invention include achieving effects that cannot be obtained with conventional technology, which are derived from the various configurations shown in the "Modes for Carrying Out the Invention" described later. [Means for solving the problem]

[0006] The disclosed braking device can be implemented in the following embodiments (examples of application) and solves at least some of the above-mentioned problems. Each of the embodiments from Embodiment 2 onward is an additional embodiment that can be appropriately selected and each is an embodiment that can be omitted. None of the embodiments from Embodiment 2 onward disclose any embodiments or configurations that are essential to this case.

[0007] Embodiment 1. The brake device disclosed is a brake device for braking the wheels of a vehicle, comprising a brake disc, a caliper, and a reverse rotation mechanism. The brake disc is formed in a disc shape and is mounted coaxially with the axle. The caliper generates a braking force by applying a pressing force to the brake disc. The reverse rotation mechanism is interposed between the axle and the brake disc and rotates the brake disc in the opposite direction to the axle.

[0008] Embodiment 2. With respect to embodiments including Embodiment 1 described above, it is preferable that the reverse rotation mechanism is a planetary gear mechanism comprising a sun gear that rotates integrally with the axle, a ring gear that rotates integrally with the brake disc, planetary gears that mesh with the sun gear and the ring gear, and a carrier shaft that is fixed to the vehicle body with the planetary gears supported.

[0009] Embodiment 3. With respect to embodiments including Embodiment 2 described above, it is preferable that the number of teeth of the ring gear is the same as the number of teeth of the sun gear. [Effects of the Invention]

[0010] The load acting on the wheels during braking includes a first load originating from vehicle inertia and a second load originating from braking torque. According to the disclosed braking device, the sign of the second load relative to the first load can be reversed by rotating the brake disc in the opposite direction to the axle using a reverse rotation mechanism. This can reduce the amount of load transfer in the longitudinal direction of the vehicle and improve the longitudinal braking force distribution of the vehicle. For example, the braking force distribution to the front wheels can be reduced, and the braking force distribution to the rear wheels can be increased, thereby stabilizing the vehicle's behavior.

Brief Description of the Drawings

[0011] [Figure 1] It is a diagram for explaining the configuration of a vehicle to which a braking device is applied. [Figure 2] It is a perspective view for explaining the structure of the braking device according to the embodiment. [Figure 3] It is a graph showing the relationship between the front-wheel braking force and the rear-wheel braking force. [Figure 4] It is a perspective view for explaining the structure of the braking device according to the modification.

Modes for Carrying Out the Invention

[0012] The disclosed braking device is for braking the wheels of a vehicle. The number of wheels of the vehicle to which this braking device is applied is not restricted. Vehicles to which it is applicable include two-wheeled vehicles, three-wheeled vehicles, four-wheeled vehicles, etc. When a pair of wheels is provided on the left and right (for example, in the case of the rear wheels of a three-wheeled vehicle, the front wheels of a four-wheeled vehicle, the rear wheels of a four-wheeled vehicle, etc.), it is preferable that this braking device is applied to each of the pair of left and right wheels. In a four-wheeled vehicle, the wheels braked by this braking device may be only the front wheels, only the rear wheels, but it is preferable that they are all the wheels.

[0013] The disclosed braking device is a type of disc brake device. The disc brake device generates the braking force of the wheels by pressing (or sandwiching) a brake pad against a disc-shaped brake disc (disc rotor). In the disc brake device according to the prior art, the brake disc rotates integrally with the axle (see, for example, Patent Document 1).

[0014] In contrast, in the disclosed braking device, the brake disk does not rotate integrally with the axle. In the disclosed braking device, the brake disk is provided so as to rotate in the reverse direction with respect to the axle. In the disclosed braking device, the load movement direction resulting from the braking torque is opposite to the load movement direction resulting from the vehicle inertia. As a result, the amount of load movement in the longitudinal direction of the vehicle is reduced, and the braking force distribution in the longitudinal direction of the vehicle is improved.

Embodiment

[0015] [1. Vehicle] FIG. 1 is a diagram for explaining the configuration of a braking device 4 and a vehicle 1 according to an embodiment. The vehicle 1 is provided with a brake pedal 2, a master cylinder 3, and a braking device 4. The master cylinder 3 generates a brake hydraulic pressure corresponding to the depression amount of the brake pedal 2. A brake booster for amplifying the stepping force input to the brake pedal 2 is provided between the master cylinder 3 and the brake pedal 2. The brake hydraulic pressure generated by the master cylinder 3 is transmitted to the braking device 4 via a hydraulic circuit.

[0016] The braking device 4 is applied to each wheel (front left wheel, front right wheel, rear left wheel, rear right wheel) provided on the vehicle 1 one by one. FIG. 2 is a perspective view for explaining the structure of the braking device 4. The white arrow in FIG. 2 represents the outside in the vehicle width direction (wheel side). The axle 5, which is the rotation center axis of the wheel, is supported by the vehicle body 8 (for example, a knuckle arm) via a wheel bearing 9. A center hub (not shown) is fixed to the outside in the vehicle width direction of the axle 5. The wheel of the wheel is fastened and fixed to the center hub.

[0017] The braking device 4 includes a brake disk 6, a caliper 7, and a planetary gear mechanism 10. The brake disk 6 has a disk shape (record disk shape) with a round hole in the central part and is arranged coaxially with the axle 5. The brake disk 6 is formed, for example, in a shape in which two perforated disks arranged in parallel are connected while being separated from each other. Holes and grooves (not shown) for improving heat dissipation may be formed in the brake disk 6.

[0018] The caliper 7 is a device that reduces the rotational speed of the brake disc 6 by pressing brake pads against the brake disc 6. The brake pads are pressed against the brake disc 6 with a pressing force corresponding to the hydraulic pressure of the hydraulic circuit. The brake pads are arranged in pairs, for example, to sandwich the brake disc 6, with one pad on each side of the brake disc 6.

[0019] The planetary gear mechanism 10 is interposed between the axle 5 and the brake disc 6. This planetary gear mechanism 10 functions as a counter-rotation mechanism that rotates the brake disc 6 in the opposite direction to the axle 5. The planetary gear mechanism 10 includes a sun gear 11, a ring gear 12, a planetary gear 13, and a carrier shaft 14. The sun gear 11 and the planetary gear 13 are external gears, while the ring gear 12 is an internal gear.

[0020] The sun gear 11 is fixed to the axle 5 and rotates integrally with the axle 5. The ring gear 12 is formed integrally with, for example, the brake disc 6 and rotates integrally with the brake disc 6. The internal teeth of the ring gear 12 are arranged along the inner circumference of a round hole provided in the center of the brake disc 6. The ring gear 12 may be formed separately from the brake disc 6. The ring gear 12 rotates integrally with the brake disc 6 and is fixed to the brake disc 6.

[0021] The planetary gear 13 is provided to mesh with the sun gear 11 and the ring gear 12, respectively. The planetary gear 13 is rotatably supported on the carrier shaft 14 via a gear bearing 15. The carrier shaft 14 is fixed to the vehicle body 8 with the planetary gear 13 supported on it. Therefore, the position of the rotation axis of the planetary gear 13 is fixed with respect to the vehicle body 8 and the axle 5 (with respect to the rotation axis of the sun gear 11). In the example shown in Figure 2, three planetary gears 13 are arranged around the sun gear 11, but the number of planetary gears 13 can be changed as appropriate.

[0022] Let the number of teeth of the sun gear 11 be A, the number of teeth of the ring gear 12 be B, the angular velocity of the sun gear 11 be ω A and the angular velocity of the ring gear 12 be ω B When this is the case, the relationship between the angular velocities ω A and ω B is given by "ω B = -ω A (A / B)". Also, in this embodiment, the number of teeth B of the ring gear 12 is set to be the same as the number of teeth A of the sun gear 11. In other words, the absolute value |ω B | of the angular velocity of the ring gear 12 is the same as the absolute value |ω A | of the angular velocity of the sun gear 11. With such a configuration, the brake disk 6 rotates in the reverse direction at the same speed as the axle 5.

[0023] [2. Function] As shown in FIG. 1, let the wheelbase of the vehicle 1 be L [m] and the tire radius be R [m]. Also, let the weight of the vehicle 1 be W [N], the height of the center of gravity from the road surface be H [m], and the gravitational acceleration be g [m / s 2 . Here, assuming a conventional braking device in which the brake disk 6 rotates integrally with the axle 5, the load transfer when the vehicle 1 is decelerated will be considered. When the deceleration is a [m / s 2 , the relationship between the static front axle load W f [N] and the dynamic front axle load W f ′ [N] is given by the following formula 1, and the relationship between the static rear axle load W r [N] and the dynamic rear axle load W r ′ [N] is given by the following formula 2.

[0024]

Equation

[0025] In equations 1 and 2, the second term on the right-hand side represents the load transfer due to vehicle inertia (the load that moves due to vehicle inertia), and the third term represents the load transfer due to braking torque (the load that moves due to braking torque). Here, the former is called the first load, and the latter is called the second load. When the rotation direction of the axle 5 and the rotation direction of the brake disc 6 are the same, the first load and the second load have the same sign. Therefore, the greater the deceleration a, the greater the dynamic front axle load W. f ′ tends to increase excessively, and dynamic rear axle load W r It can be seen that ' tends to decrease excessively.

[0026] On the other hand, in this embodiment, the brake disc 6 rotates in the opposite direction to the axle 5. As a result, the static front axle load W in this embodiment f and dynamic front axle load W f The relationship with ′ is given by the following equation 3, where static rear axle load W r and dynamic rear axle load W r The relationship with ′ is given by the following equation 4. When the rotation direction of the axle 5 and the rotation direction of the brake disc 6 are opposite, the first load and the second load will have opposite signs. Therefore, compared to the case where the rotation direction of the axle 5 and the rotation direction of the brake disc 6 are the same, the dynamic front axle load W f The increase of ' is suppressed, and the dynamic rear axle load W r It can be seen that the decrease of ′ is suppressed.

[0027]

number

[0028] Furthermore, by rearranging equations 1 to 4 above, we obtain equations 5 to 8 below. The second term on the right-hand side of equations 5 to 8 represents the load transfer during deceleration (the load that moves during deceleration), and this is called the third load.

[0029]

number

[0030] When the rotation direction of the axle 5 and the rotation direction of the brake disc 6 are the same, the third load will be proportional to the height of the center of gravity H, as shown in equations 5 and 6. It is difficult to make the height of the center of gravity H zero. Therefore, it can be seen that, in practice, the third load cannot be made zero.

[0031] On the other hand, when the rotation direction of the axle 5 and the rotation direction of the brake disc 6 are opposite, the third load will be of a magnitude corresponding to the value obtained by subtracting the tire diameter 2R from the center of gravity height H, as shown in equations 7 and 8. In other words, by setting the center of gravity height H to the same value as the tire diameter 2R, the third load becomes 0. Therefore, in this case, it can be seen that the load transfer during deceleration can be canceled out.

[0032] Figure 3 is a graph showing the relationship between front wheel braking force and rear wheel braking force. The solid line graph shows the relationship when the rotation direction of the axle 5 and the rotation direction of the brake disc 6 are the same. In this case, the increase in front wheel braking force when the deceleration a is increased by a predetermined value is greater than the increase in rear wheel braking force. In other words, as the front wheel braking force increases, the proportion of the braking force burden on the front wheels relative to the rear wheels increases, resulting in a more unbalanced distribution of braking force in the front-to-rear direction.

[0033] In contrast, the dashed line graph shows the relationship when the rotation direction of the axle 5 and the rotation direction of the brake disc 6 are opposite. In this case, the increase in front wheel braking force when the deceleration a is increased by a predetermined value is smaller compared to the solid line graph. This improves the balance of braking force distribution in the front-rear direction.

[0034] Furthermore, the dashed-dotted graph shows the relationship when the rotation direction of the axle 5 and the rotation direction of the brake disc 6 are opposite, and the third load shown in equations 7 and 8 is 0. In this case, regardless of the magnitude of the deceleration a, the braking force of the front wheels and the braking force of the rear wheels become the same, and the balance of the braking force distribution in the front-rear direction is optimized.

[0035] [3. Effects] (1) The braking device 4 described above comprises a brake disc 6, a caliper 7, and a planetary gear mechanism 10 (reverse rotation mechanism). The brake disc 6 is formed in a disc shape and is mounted coaxially with the axle 5. The caliper 7 generates braking force by applying a pressing force to the brake disc 6. The planetary gear mechanism 10 is interposed between the axle 5 and the brake disc 6 and rotates the brake disc 6 in the opposite direction to the axle 5.

[0036] As shown in Equations 3 and 4, the load acting on the wheels during braking includes a first load (second term on the right-hand side) derived from vehicle inertia and a second load (third term on the right-hand side) derived from braking torque. According to the braking device 4 described above, the sign of the second load relative to the first load can be reversed by rotating the brake disc 6 in the opposite direction to the axle 5. This reduces the amount of load transfer in the longitudinal direction of the vehicle 1 and improves the distribution of braking force in the longitudinal direction of the vehicle 1.

[0037] For example, the braking force distribution to the front wheels can be reduced, and the braking force distribution to the rear wheels can be increased. Therefore, the vehicle's behavior can be stabilized. Furthermore, by applying the above-mentioned braking device 4 to at least the front wheels, the braking force distribution to the front wheels can be reduced, preventing an excessive increase in front wheel load. Also, by applying the above-mentioned braking device 4 to at least the rear wheels, the braking force distribution to the rear wheels can be increased, preventing a loss of rear wheel load. Therefore, the vehicle's behavior can be stabilized.

[0038] (2) The planetary gear mechanism 10 described above includes a sun gear 11 that rotates integrally with the axle 5, a ring gear 12 that rotates integrally with the brake disc 6, a planetary gear 13 that meshes with the sun gear 11 and the ring gear 12, and a carrier shaft 14 that is fixed to the vehicle body 8 of the vehicle 1 with the planetary gear 13 supported. This allows the brake disc 6 to be easily rotated in the reverse direction with a simple configuration. In addition, the entire braking device 4 can be made compact, improving ease of mounting on the vehicle 1 and saving space.

[0039] (3) In the planetary gear mechanism 10 described above, the number of teeth B of the ring gear 12 is set to be the same as the number of teeth A of the sun gear 11. As a result, the brake disc 6 rotates in the opposite direction at the same speed as the axle 5. Therefore, the durability performance of the brake disc 6 and caliper 7 (brake pads) can be maintained at the same level as when the brake disc 6 rotates integrally with the axle 5. In other words, existing brake discs 6 and calipers 7 (brake pads) can be easily reused.

[0040] [4. Others] The above embodiments are merely illustrative examples, and there is no intention to exclude various modifications or applications of techniques not explicitly stated in these embodiments. Each configuration of these embodiments can be modified in various ways without departing from their intended purpose. Furthermore, each configuration of these embodiments can be selected or combined as needed.

[0041] Figure 4 is a perspective view illustrating the structure of a modified braking device 4 in which the planetary gear mechanism 10 is replaced with a gear train 20. The gear train 20 is interposed between the axle 5 and the brake disc 6, similar to the planetary gear mechanism 10. This gear train 20 functions as a counter-rotation mechanism that rotates the brake disc 6 in the opposite direction to the axle 5. The gear train 20 has a first gear 21, a second gear 22, a third gear 23, and a fourth gear 24. Each of the first gear 21, second gear 22, third gear 23, and fourth gear 24 is an external gear.

[0042] The first gear 21 is fixed to the axle 5 and rotates integrally with the axle 5. The second gear 22 is provided to mesh with the first gear 21. The second gear 22 is rotatably supported on the first shaft 25 via the first gear bearing 27. The first shaft 25 is fixed to the vehicle body 8 with the second gear 22 supported on it. The direction of rotation of the second gear 22 is opposite to the direction of rotation of the first gear 21.

[0043] The third gear 23 is provided to mesh with the second gear 22. The third gear 23 is rotatably supported on the second shaft 26 via the second gear bearing 28. As shown in Figure 4, the third gear 23 is formed with a long tooth width. The second shaft 26 is fixed to the vehicle body 8 with the third gear 23 supported on it. The direction of rotation of the third gear 23 is opposite to the direction of rotation of the second gear 22, and is the same as the direction of rotation of the first gear 21 and the axle 5.

[0044] The fourth gear 24 is positioned to mesh with the third gear 23 and is fixed to the brake disc 6, rotating integrally with the brake disc 6. The fourth gear 24 is formed integrally with the brake disc 6, for example. A round hole is provided in the center of the brake disc 6, and the axle 5 is inserted through the inside of it. The rotation direction of the fourth gear 24 is opposite to the rotation direction of the first gear 21 and the axle 5.

[0045] Even with this configuration, the brake disc 6 can be rotated in the opposite direction to the axle 5. Therefore, the amount of load transfer in the longitudinal direction of the vehicle 1 can be reduced, and the distribution of braking force in the longitudinal direction of the vehicle 1 can be improved. In addition, an excessive increase in front wheel load can be prevented, and a decrease in rear wheel load can be prevented. Therefore, the vehicle behavior can be stabilized.

[0046] Furthermore, the number of gears interposed in the power transmission path from the first gear 21 to the fourth gear 24 can be increased. For example, it is possible to interpose two gears between the third gear 23 and the fourth gear 24, making the number of teeth of the fourth gear 24 the same as the number of teeth of the first gear 21. With such a configuration, the brake disc 6 can be rotated in the opposite direction at the same speed as the axle 5. Therefore, the durability performance of the brake disc 6 and caliper 7 (brake pad) can be maintained at the same level as when the brake disc 6 rotates integrally with the axle 5. [Industrial applicability]

[0047] This technology is applicable to the manufacturing industry of vehicle braking systems and to the manufacturing industry of vehicles equipped with these braking systems. [Explanation of symbols]

[0048] 1 vehicle 2. Brake pedal 3 Master Cylinder 4 Braking device 5 axles 6 Brake discs 7 Caliper 8 car bodies 9 Wheel bearings 10. Planetary gear mechanism (reverse rotation mechanism) 11 Sangiya 12 Ring gear 13 Planetary Gear 14 Career axes 15 Gear bearings 20. Gear train (reverse rotation mechanism) 21 First gear 22 Second gear 23 Third gear 24 Fourth gear 25 First axis 26 Second axis 27 First gear bearing 28 Second gear bearing

Claims

1. A braking device for braking the wheels of a vehicle, A brake disc formed in a disc shape and mounted coaxially with the axle, A caliper that generates braking force by applying a pressing force to the brake disc, A reverse rotation mechanism is interposed between the axle and the brake disc, causing the brake disc to rotate in the opposite direction to the axle. A braking device characterized by being equipped with the following.

2. The aforementioned reverse rotation mechanism is a planetary gear mechanism, A sun gear that rotates integrally with the axle, A ring gear that rotates integrally with the brake disc, A planetary gear that meshes with the sun gear and the ring gear, It has a carrier shaft that is fixed to the vehicle body with the planetary gear supported on it. The braking device according to claim 1, characterized in that...

3. The number of teeth of the ring gear is the same as the number of teeth of the sun gear. The braking device according to claim 2, characterized in that...

Images