Disc brake device

Abstract

This disc brake device performs braking of a disc rotor (1) by pressing a brake pad (3) against a rotor surface (1a) by means of a pad pressing mechanism (4). The pad pressing mechanism (4) comprises: a cam lever unit (11) that has an eccentric camshaft (12); a cam holder (13); an adjuster nut (31); a spindle (32); an anchor plate (14) that guides axial movement of the cam holder (13); and a guide plate (16) that guides axial movement of the adjuster nut (31). During braking, the camshaft (12) boosts the force transmitted by the rotation of the cam lever unit (11) and moves the cam holder (13) axially outward.

Description

Disk Brake Device

[0001] This disclosure relates to a disk brake device.

[0002] Conventionally, disk brake devices have been widely used to brake vehicles such as automobiles and trains. In this type of disk brake device, during braking, a pair of brake pads arranged on both axial sides of a disk rotor that rotates with the wheel are configured to be pressed against both axial side surfaces of the disk rotor (hereinafter also referred to as "rotor surfaces") by a pad pressing mechanism.

[0003] The disk brake device disclosed in Patent Document 1 includes a brake caliper straddling so as to sandwich a brake disk (disk rotor) from both sides, and a pair of brake pads are arranged on the brake caliper. In this disk brake device, during braking, the brake pad on the operating side is pressed against the brake disk by an operating device, and then, due to the movement of the brake caliper that moves based on the reaction force, the brake pad on the reaction force side is configured to be pressed against the brake disk.

[0004] More specifically, the operating device has a spindle assembly, and the spindle assembly is configured to be slidable axially via a swivel lever engaged with a push rod of a brake cylinder and to be pressed against the brake pad on the operating side. That is, in the disk brake device disclosed in Patent Document 1, during braking, when the swivel lever is swiveled by the push rod, the spindle assembly is moved in the axial direction of the brake disk toward the direction of the brake pad, and the movement of this spindle assembly causes the brake pad to be pressed against the brake disk.

[0005] Japanese Patent Application Publication No. 2018-527535

[0006] By the way, in the disk brake device as described above, in order to appropriately brake the vehicle, it is necessary to properly position the spindle assembly and then configure it to smoothly move in the above axial direction so that the brake pad is pressed against the brake disk.

[0007] This disclosure has been made in view of the circumstances described above, and its purpose is to provide a disc brake device in which a pad pressing mechanism for pressing a brake pad against the rotor surface of a disc rotor is properly positioned and can move smoothly in the axial direction of the disc rotor.

[0008] To achieve the aforementioned objectives, the disc brake device of this disclosure is characterized by the following [1] to

[10] .

[0009] [1] A disc brake device comprising: a disc rotor that rotates with a wheel; a brake pad provided opposite the rotor surface of the disc rotor; a pad pressing mechanism for pressing the brake pad against the rotor surface; and a cylinder body housing the pad pressing mechanism, wherein the disc brake device brakes the disc rotor by pressing the brake pad against the rotor surface using the pad pressing mechanism, the pad pressing mechanism comprising: a cam lever unit having an eccentric camshaft; a cam holder that pivotally supports the camshaft so that the cam lever unit can rotate around the camshaft and is movable in the axial direction on the disc rotor; an adjuster nut located axially outward on the disc rotor from the cam holder and having a fitting portion fitted into the cam holder; a spindle that screws into the adjuster nut and presses the brake pad against the rotor surface; and an anchor plate attached to the cylinder body axially inward on the disc rotor from the cam holder and guiding the axial movement of the cam holder. A disc brake device comprising: a guide plate fixed to the axially outer end of the cylinder body, having a hole into which the adjuster nut is inserted, and guiding the axial movement of the adjuster nut, wherein the camshaft, during braking, amplifies the force transmitted by the rotation of the cam lever unit to move the cam holder axially outward.

[0010] [2] The disc brake device described in [1] above, wherein the cam holder has a flange portion through which a pair of holes are provided, each through which a pair of bolts for fixing the guide plate to the cylinder body are inserted.

[0011] [3] The disc brake device described in [1] above, wherein the pad pressing mechanism has a cam holder return spring that biases the cam holder to return to its initial position when not braking.

[0012] [4] The disc brake device described in [3] above, wherein the cam holder return spring is arranged coaxially with a pair of bolts for fixing the guide plate to the cylinder body.

[0013] [5] The disc brake device described in [1] above, further comprising an air cylinder housing a push rod that moves forward by air pressure, wherein the cam lever unit has a roller supported by a guide groove at the tip of the push rod and to which thrust from the air cylinder is transmitted.

[0014] [6] The disc brake device described in [5] above, wherein the cam lever unit further comprises a pair of cam levers that hold the cam shaft, and the roller is positioned between the pair of cam levers.

[0015] [7] The disc brake device described in [1] above, wherein the camshaft is composed of a cylindrical cam body and a pair of eccentric portions provided at both ends of the cam body in the extending direction and eccentric to the cam body, and the eccentric portions are provided with bearings that are in contact with an anchor plate.

[0016] [8] The disc brake device described in [1] above, wherein the cam holder is provided with a boss portion that protrudes inward in the axial direction, and the boss portion is inserted through a guide hole provided in the anchor plate and a guide hole provided in the cylinder body.

[0017] [9] The disc brake device described in [1] above, wherein the anchor plate has a horizontal guide surface that extends in the axial direction and guides the axial movement of the cam holder.

[0018]

[10] The disc brake device described in [1] above, wherein the cylinder body is provided with a fitting groove into which the anchor plate is fitted.

[0019] According to the configuration described in [1] above, when the pad pressing mechanism presses the brake pad against the rotor surface during braking, or when braking is released, the cam holder, the adjuster nut whose fitting portion is fitted inside the cam holder, and the spindle which is screwed into the adjuster nut are configured to move in the axial direction, and an anchor plate that guides the axial movement of the cam holder and a guide plate that guides the axial movement of the adjuster nut are provided. In other words, with this configuration, when the cam holder, adjuster nut, and spindle move in the axial direction, the cam holder is guided by the anchor plate on the axially inward side, and the adjuster nut is guided by the guide plate on the axially outward side. Therefore, with this configuration, the pad pressing mechanism can be properly positioned and move smoothly in the axial direction.

[0020] According to the configuration described in [2] above, a pair of bolts for fixing the guide plate to the cylinder body are inserted through a pair of holes in the flange portion of the cam holder, so that the cam holder can be guided by the pair of bolts when it moves in the axial direction.

[0021] According to the configuration described in [3] above, the pad pressing mechanism has a cam holder return spring, which allows the cam holder, and consequently the adjuster nut, to be returned to its initial position by the cam holder return spring when not braking, and especially when the brake is released. In this case as well, the cam holder is guided by the anchor plate on the axially inward side, and the adjuster nut is guided by the guide plate on the axially outward side.

[0022] According to the configuration described in [4] above, the cam holder return spring is arranged coaxially with a pair of bolts, which reduces the number of parts and allows for miniaturization of the disc brake device.

[0023] According to the configuration described in [5] above, the cam lever unit has a roller supported by a guide groove at the tip of the push rod of the air cylinder, thereby reducing friction between the push rod and the cam lever unit and suppressing energy loss related to thrust from the air cylinder.

[0024] According to the configuration described in [6] above, the cam lever unit is composed of multiple members, each having a cam lever and a roller, thereby improving design flexibility and maintainability.

[0025] According to the configuration described in [7] above, a bearing is provided in contact with the anchor plate at the eccentric portion of the camshaft, thereby reducing friction between the eccentric portion and the anchor plate, and suppressing the loss of energy related to the power assist described above.

[0026] According to the configuration described in [8] above, the boss portion of the cam holder is inserted through the guide hole of the anchor plate and the guide hole of the cylinder body, so that the cam holder can be guided more properly by these guide holes when it moves in the axial direction.

[0027] According to the configuration described in [9] above, the anchor plate has a horizontal guide surface, which allows the cam holder to be guided more appropriately during axial movement of the cam holder.

[0028] According to the configuration described in

[10] above, the anchor plate is securely fixed to the cylinder body by being fitted into the fitting groove of the cylinder body, so that the axial movement of the cam holder can be guided more accurately and stably by the anchor plate.

[0029] Figure 1 is a perspective view of a disc brake device according to one embodiment of the present disclosure (however, the disc rotor is not shown). Figure 2 is a cross-sectional view taken along line A-A of Figure 1, showing the state when not braking. Figure 3 is a cross-sectional view taken along line A-A of Figure 1, showing the state when braking. Figure 4 is a cross-sectional view taken along line B-B of Figure 1, showing the state when not braking (however, the disc rotor is not shown). Figure 5 is a perspective view for explaining the cam lever unit. Figure 6 is a cross-sectional view of the main part showing how the anchor plate is fixed to the cylinder body. Figure 7 is a perspective view for explaining the gap adjustment mechanism. Figure 8 is a view of Figure 7 from the right side of the paper. Figure 9 is a view of Figure 7 from the top side of the paper. Figure 10 is a view of Figure 7 from the bottom side of the paper. Figure 11 is a diagram for explaining the operation of the gap adjustment mechanism, where (a) shows the state when not braking and when gap adjustment is not required, (b) shows the state when braking and when gap adjustment is not required, (c) shows the state when braking and when gap adjustment is required, and (d) shows the state after gap adjustment. Figure 12 shows a first modified example of the disc brake device, and corresponds to Figure 8. Figure 13 shows a second modified example of the disc brake device, and corresponds to Figure 4.

[0030] <Embodiment> A disc brake device according to one embodiment of the present disclosure will be described below with reference to the drawings.

[0031] [Overall Configuration] The disc brake device in this example is of the floating caliper type and, as shown in Figure 1, etc., comprises a disc rotor 1 (see Figures 2-3) that rotates together with the wheel (not shown) and a brake caliper 2 that straddles the disc rotor 1 so as to sandwich it from both sides. As shown in Figures 2-3, the brake caliper 2 supports two brake pads 3 (3a, 3b) that are arranged to face the rotor surface 1a of the disc rotor 1, so as to be displaceable in the axial direction of the disc rotor 1 (hereinafter also simply referred to as "axial direction"; see Figure 2, etc.).

[0032] Furthermore, as shown in Figure 1, the disc brake device includes a pad pressing mechanism 4 for pressing the brake pad 3 against the rotor surface 1a, and a cylinder body 5 that houses the pad pressing mechanism 4. The brake pad 3 is supported by a pad pressing plate 8, and the pad pressing mechanism 4 presses the brake pad 3 against the rotor surface 1a via this pad pressing plate 8. In this example, an air cylinder 6 is used as an actuator incorporated into the disc brake device, and the air cylinder 6 has a push rod 7 inside that moves forward by air pressure and transmits its thrust to the pad pressing mechanism 4.

[0033] In other words, when the disc brake system is braking, the air cylinder 6 receives pressure (pneumatic pressure), causing the push rod 7 to move forward. This thrust is transmitted to the pad pressing mechanism 4, which then amplifies (multiplies) the thrust transmitted by the push rod 7 to press the brake pad 3 against the rotor surface 1a, thereby generating braking force.

[0034] In this example, since the disc brake system is of the floating caliper type, first the brake pad 3a on the operating side is pressed against the rotor surface 1a by the pad pressing mechanism 4, and then the brake pad 3b on the reaction side is pressed against the rotor surface 1a by the movement of the brake caliper 2, which moves based on the reaction force.

[0035] [Pad Pressing Mechanism] As shown in Figure 2, the pad pressing mechanism 4 includes a cam lever unit 11 having an eccentric camshaft 12, and a cam holder 13 that pivotally supports the camshaft 12 so that the cam lever unit 11 can rotate around the camshaft 12, and is also movable in the axial direction. The cam lever unit 11 and the cam holder 13 primarily play the role of amplifying the thrust transmitted from the push rod 7.

[0036] As shown in Figure 5 and other figures, the cam lever unit 11 integrally comprises a pair of cam levers 111 that hold the camshaft 12 and a roller 112 positioned between one end 111a of the pair of cam levers 111, and is formed in a bifurcated shape with an external appearance that is roughly rectangular U-shaped. The other end 111b of each cam lever 111 is provided with a holding portion 111c that holds the camshaft 12 in a position where it is inserted. The roller 112 is supported by a guide groove 7a at the tip of the push rod 7, and thrust from the air cylinder 6 is transmitted to it (see Figure 3).

[0037] The camshaft 12 has the function of amplifying the force transmitted by the rotation of the cam lever unit 11 during braking, thereby moving the cam holder 13 axially outward. The camshaft 12 consists of a cylindrical cam body 121 and a pair of eccentric portions 122 provided at both ends of the cam body 121 in the extending direction (corresponding to the width direction above) and eccentric to the cam body 121. The cam body 121 is pivotally supported by the cam holder 13, and each eccentric portion 122 is located outside the cam holder 13 (see Figure 4).

[0038] Each eccentric portion 122 is formed eccentrically with respect to the rotation center of the cam body 121, and the rotation centers of each eccentric portion 122 are also formed to be different from each other. Furthermore, each eccentric portion 122 is formed to be smaller in diameter than the cam body 121, and each eccentric portion 122 is provided with a bearing 21 that is larger in diameter than the eccentric portion 122. This bearing 21 is provided to reduce the rotational resistance of the camshaft 12 and is positioned in contact with the anchor plate 14, which will be described later (see Figures 2 to 4).

[0039] As shown in Figure 2, the cam holder 13 is integrally constructed with a holder body portion 132 and a boss portion 133, arranged in order from the axial outer side. A flange portion 131 extending in the width direction is formed at the axial outer end of the holder body portion 132 (see Figure 4, etc.). A pair of holes 131a are formed in this flange portion 131a, through which a pair of bolts 22 for fixing the guide plate 16 (described later) to the cylinder body 5 are inserted.

[0040] Furthermore, the holder body portion 132 is provided with a fitting groove portion 134 at its axial outer end, which is recessed in the axial direction and into which an adjuster nut 31, described later, is fitted. In addition, the holder body portion 132 is provided with a through hole (reference numeral omitted) that extends through in the width direction and pivotally supports the camshaft 12. The boss portion 133 is formed to protrude axially inward from the axial inner end of the holder body portion 132 and is slidably inserted into a guide hole 142 provided in the anchor plate 14 and a guide hole 5a provided in the cylinder body 5. Note that the guide hole 142 of the anchor plate 14 and the guide hole 5a of the cylinder body 5 are formed to communicate in the axial direction.

[0041] Furthermore, as shown in Figure 2 and other figures, the pad pressing mechanism 4 is attached to the cylinder body 5 axially inward from the cam holder 13 and includes an anchor plate 14 that guides the axial movement of the cam holder 13. As shown in Figure 6, the anchor plate 14 is fixed to the cylinder body 5 by being fitted into a fitting groove 5b provided in the cylinder body 5.

[0042] The anchor plate 14 is formed in a roughly rectangular shape that is long in the width direction, and a horizontal guide surface 141 is provided at the center of its lower end, extending in the axial direction to guide the axial movement of the cam holder 13. The cam holder 13 is slidably mounted on this horizontal guide surface 141. The anchor plate 14 is also provided with a contact portion 143 (see Figure 9, etc.) that protrudes axially outward at a position corresponding to the bearing 21, and whose protruding end surface contacts the bearing 21.

[0043] Furthermore, as shown in Fig. 2 and the like, the pad pressing mechanism 4 includes a gap adjusting mechanism 15 that adjusts the size of the gap between the disk rotor 1 and the brake pad 3. The gap adjusting mechanism 15 is located axially outside the disk rotor 1 with respect to the cam holder 13 and includes an adjuster nut 31 having a fitting portion 311 that is fitted inside the cam holder 13, and a spindle 32 that is screwed with the adjuster nut 31 and presses the brake pad 3 against the rotor surface 1a. Details of the gap adjusting mechanism 15 will be described later.

[0044] Furthermore, as shown in Fig. 2 and the like, the pad pressing mechanism 4 has a hole portion 161 into which the adjuster nut 31 is inserted, and includes a guide plate 16 that guides the axial movement of the adjuster nut 31. The guide plate 16 is fixed to the axially outer end portion of the cylinder body 5 by a pair of bolts 22.

[0045] Furthermore, as shown in Fig. 4 and the like, the pad pressing mechanism 4 includes a cam holder return spring 17 that biases the cam holder 13 to return to the initial position when not in braking. The cam holder return spring 17 is disposed between the flange portion 131 of the cam holder 13 and the guide plate 16, has a set length when not in braking, and is configured to be energized by being deformed so as to contract as the cam holder 13 moves axially outward during braking.

[0046] Here, the pad pressing mechanism 4 configured as described above operates as follows. When the air cylinder 6 receives pressure (pneumatic pressure) and the push rod 7 advances during braking of the disk brake device, the cam lever unit 11 is pressed axially outward by the push rod 7 at the end on the roller 112 side and rotates around the cam shaft 12 (counterclockwise in Figs. 2 to 3).

[0047] Subsequently, as the cam lever unit 11 rotates, the camshaft 12 rotates about the central axis of the cam body 121 (counterclockwise in FIGS. 2 to 3). As a result, a force (action) is applied to the contact portion 143 of the anchor plate 14 from the eccentric portion 122 axially inward via the bearing 21. Then, since the eccentric portion 122 of the camshaft 12 contacts the anchor plate 14 via the bearing 21 described later, the cam holder 13 receives a reaction (reaction force) from the anchor plate 14 against the above action and is moved axially outward. That is, the camshaft 12 multiplies the force transmitted by the rotation of the cam lever unit 11 and moves the cam holder 13 axially outward.

[0048] As a result, the fitting portion 311, the adjuster nut 31 fitted into the fitting groove portion 134 of the cam holder 13, and the spindle 32 screwed with the adjuster nut 31 are also moved axially outward, and the spindle 32 presses the brake pad 3a on the operating side against the rotor surface 1a via the pad pressing plate 8. Thereafter, as described above, the brake pad 3b on the reaction force side is pressed against the rotor surface 1a, and a braking force is generated.

[0049] Although details will be described later, in the disk brake device of this example, gap adjustment is performed by the gap adjustment mechanism 15 before the spindle 32 presses the brake pad 3 against the rotor surface 1a.

[0050] Thereafter, when the braking is released, the push rod 7 retracts, and the cam holder 13 is urged by the cam holder return spring 17 and returned to the initial position, so that the adjuster nut 31 and the spindle 32 are moved axially inward. As a result, a gap exists between the rotor surface 1a and the brake pad 3.

[0051] Incidentally, the axial movement of the pad pressing mechanism 4 during braking and brake release as described above is guided so that the pad pressing mechanism 4 can move smoothly along the axial direction after being positioned by the horizontal guide surface 141 of the anchor plate 14 on which the cam holder 13 is mounted, the guide hole 142 of the anchor plate 14 through which the boss portion 133 of the cam holder 13 is inserted, the guide hole 5a of the cylinder body 5, the pair of bolts 22 inserted through the pair of holes 131a of the flange portion 131, and the hole 161 of the guide plate 16 into which the adjuster nut 31 is inserted.

[0052] In other words, in a disc brake system, the pad pressing mechanism 4 is guided by an anchor plate 14 in the axially inner region and by a guide plate 16 in the axially outer region, so that the pad pressing mechanism 4 can move smoothly along the axial direction.

[0053] [Gap Adjustment Mechanism] The gap adjustment mechanism 15 includes an adjuster nut 31 and a spindle 32, as described above. As shown in Figure 2, the adjuster nut 31 is integrally formed with the fitting portion 311 and a substantially cylindrical nut body portion 312, starting from the axial inner side. The axial inner end of the spindle 32 is screwed into the nut body portion 312. The spindle 32 is fixed to the pad pressing plate 8 so as not to rotate via a rotation prevention member 23, preventing the spindle 32 from rotating together with the rotation of the adjuster nut 31.

[0054] Furthermore, as shown in Figure 8 and other figures, the gap adjustment mechanism 15 includes a ratchet gear 33 and a ring member 34 that are fitted onto the nut body portion 312 of the adjuster nut 31. The ratchet gear 33 and the ring member 34 are arranged in this order from the axial inner side, with the ratchet gear 33 fitted so as to rotate together with the adjuster nut 31, and the ring member 34 fitted so as to be rotatable on the outer circumferential surface of the nut body portion 312 (but not to rotate together with the adjuster nut 31) with its central axis O substantially coinciding with the nut body portion 312.

[0055] The ratchet gear 33 is formed in a substantially short cylindrical shape, and multiple teeth 331 (see Figure 11) are arranged circumferentially along its entire outer surface. The ring member 34 is also provided with a first lever 35 that protrudes radially (upward in Figure 8) from the nut body 312. This first lever 35 is formed in a substantially L-shaped plate shape, with one end screw-fastened to the ring member 34 and the other end protruding radially. In this specification, the other end (the radially protruding portion) will be mainly referred to as the first lever 35.

[0056] Furthermore, the ratchet gear 33 is detachably fixed to the adjuster nut 31 by a fixing means such as a spring pin. As will be described in detail later, in this disc brake device, the ratchet gear 33 is rotated by a ratchet 37, which will be described later. At this time, the adjuster nut 31 also rotates together with the ratchet gear 33 to adjust the gap. For this reason, the amount of rotation of the adjuster nut 31, i.e., the fineness of the gap adjustment, changes depending on the number of teeth on the ratchet gear 33. In other words, in this disc brake device, ratchet gears 33 with different numbers of teeth are appropriately replaced according to changes in the vehicle model and the specifications of the adjuster, etc. Therefore, because the ratchet gear 33 is detachably fixed to the adjuster nut 31, it is possible to easily respond to the above-mentioned changes in specifications.

[0057] Furthermore, the ring member 34 is fixed to the adjuster nut 31 so as to be rotatable, and its axial displacement is restricted by a snap ring 61, which is a fixing member fixed to the adjuster nut 31 (see Figure 2, etc.). A spacer (not shown) may be provided between the ring member 34 and the snap ring 61. In this case, the ring member 34 is fixed to the snap ring 61 via the spacer as described above.

[0058] Furthermore, as shown in Figure 9 and other figures, the gap adjustment mechanism 15 includes a second lever 36 that is rotatably supported on the outer circumferential surface of the cam holder 13 and holds the first lever 35 in order to rotate the ring member 34, and a spring 38 that biases the second lever 36 to rotate. The second lever 36 is formed to be long in the axial direction, and the axially inner portion of the second lever 36 is rotatably supported on the outer circumferential surface of the cam holder 13. The portion of the second lever 36 that is rotatably supported on the cam holder 13 becomes the pivot center 361 of the second lever 36.

[0059] A retaining portion 362 for holding the first lever 35 is provided at the axially outer end of the second lever 36. In this example, the retaining portion 362 is formed in a bifurcated shape to clamp the first lever 35, but its shape is not particularly limited. Furthermore, a rotation restricting portion 363 for restricting the rotation of the second lever 36 when not braking is provided at the axially inner end (towards the rotation center 361). That is, when not braking, the rotation of the second lever 36 is restricted by the rotation restricting portion 363 contacting the anchor plate 14, and when braking, the cam holder 13 moves axially outward and away from the anchor plate 14, allowing the rotation restricting portion 363 to rotate by the spring 38 while still in contact with the anchor plate 14.

[0060] The spring 38 has hooks at both ends, with one end hooked onto a spring fixing part 135 (see Figure 7, etc.) provided on the cam holder 13, and the other end hooked onto a spring fixing part 364 (see Figure 7, etc.) provided on the second lever 36, thereby biasing the second lever 36 to rotate counterclockwise in Figure 9. As will be described in detail later, when braking and gap adjustment is performed, the adjuster nut 31 rotates in conjunction with the rotation of the second lever 36, moving the spindle 32 outward in the axial direction. Therefore, it is rotated in a direction that loosens the screw engagement with the spindle 32 (clockwise in this example, Figure 8). For this reason, the spring 38 biases the second lever 36 so that the adjuster nut 31 rotates in the above direction.

[0061] Furthermore, as shown in Figure 8 and other figures, the gap adjustment mechanism 15 includes a ratchet 37 that meshes with the ratchet gear 33 and rotates the ratchet gear 33 in only one direction in response to the rotation of the ring member 34, and a spring 39 that biases the ratchet 37 toward the ratchet gear 33.

[0062] The ratchet 37 is fixed to the ring member 34 so as to be rotatable together with the ring member 34, and is positioned approximately opposite the first lever 35 in the radial direction (vertical direction in Figure 8) of the adjuster nut 31, with the central axis O of the adjuster nut 31 in between (see Figures 7-10). The ratchet 37 has a pawl 371 (see Figure 11) that engages with the teeth 331 of the ratchet gear 33. Note that the pawl 371 of the ratchet 37 does not engage with the teeth 331 of the ratchet gear 33 when the disc brake device is not braking (see Figures 11(a) and 11(d)).

[0063] The spring 39 has hooks at both ends, with one end hooked onto a spring fixing part 341 (see Figure 8, etc.) provided on the ring member 34, and the other end hooked onto a spring fixing part 372 (see Figure 8, etc.) provided on the ratchet 37. When the disc brake device is braking, the spring 39 biases the pawl 371 of the ratchet 37 to engage with the teeth 331 of the ratchet gear 33 in response to the rotation of the ring member 34 (see Figures 11(b) and 11(c)).

[0064] Furthermore, as shown in Figure 9, the gap adjustment mechanism 15 includes a restricting spring 40 that biases the adjuster nut 31 axially inward, thereby restricting the rotation of the adjuster nut 31 when not braking. The restricting spring 40 is fitted into the nut body portion 312 of the adjuster nut 31 so as to be positioned between the guide plate 16 and the snap ring 61 fixed to the adjuster nut 31 (see Figure 2).

[0065] In a disc brake system, the rotation of the adjuster nut 31 is restricted when not braking by the frictional resistance between the adjuster nut 31 and the cam holder 13, which is generated by the biasing force of the restricting spring 40 on the adjuster nut 31. The restriction of the rotation of the adjuster nut 31 by the restricting spring 40 is intended to prevent unintended rotation of the adjuster nut 31. Therefore, the load of the restricting spring 40 is set to allow rotation of the adjuster nut 31 when the disc brake system is braking.

[0066] Furthermore, since the aforementioned restricting spring 40 biases the adjuster nut 31 axially inward, it assists in returning the cam holder 13 to its initial position when the brake of the disc brake device is released.

[0067] Here, the gap adjustment mechanism 15, configured as described above, operates as follows. In the following explanation, we will describe two cases as examples: when the gap between the disc rotor 1 and the brake pad 3 is less than a specified value, and when the gap is greater than or equal to a specified value. Also, as described above, the gap adjustment by the gap adjustment mechanism 15 is performed during braking, before the spindle 32 presses the brake pad 3 against the rotor surface 1a.

[0068] When the disc brake system is applied, as described above, the cam holder 13 moves axially outward, and the axially inward end face of the cam holder 13, which was in contact with the anchor plate 14 when not braking, separates from the anchor plate 14. Then, due to the biasing force of the spring 38, the second lever 36 rotates counterclockwise in Figure 9, even though the rotation restricting portion 363 of the second lever 36 is in contact with the anchor plate 14.

[0069] Next, since the first lever 35 of the ring member 34 is held by the holding portion 362 of the second lever 36, when the second lever 36 is rotated, the ring member 34 rotates clockwise in Figure 8 in conjunction with the rotation of the second lever 36. Then, the ratchet 37 also rotates in response to the rotation of the ring member 34, and consequently, the pawl 371 of the ratchet 37 engages with the teeth 331 of the ratchet gear 33 by the spring 39 (see Figure 10(b)).

[0070] Next, if the gap between the disc rotor 1 and the brake pad 3 is less than the specified value, the amount of rotation of the ratchet 37, i.e., the amount of rotation of the second lever 36, will not cause the ratchet gear 33 to rotate. Therefore, the adjuster nut 31 will not rotate, and the spindle 32 will not move axially outward relative to the adjuster nut 31, that is, the gap will not be adjusted, and the brake pad 3 will be pressed against the rotor surface 1a.

[0071] On the other hand, if the gap between the disc rotor 1 and the brake pad 3 is greater than or equal to a specified value, the rotation of the ratchet 37 causes the pawl 371 to push the teeth 331, causing the ratchet gear 33 to rotate clockwise in Figure 8 (see Figure 11(c)). Consequently, the adjuster nut 31 is also rotated clockwise in Figure 8, causing the spindle 32 to move axially outward relative to the adjuster nut 31, thus completing the gap adjustment. In other words, after the gap adjustment, the spindle 32 protrudes axially outward by the amount of the adjustment compared to before the gap adjustment. Then, after the gap adjustment is completed, the brake pad 3 is pressed against the rotor surface 1a by the spindle 32.

[0072] Subsequently, when the braking force of the disc brake device is released, the cam holder 13 returns to its initial position, and as a result, the second lever 36 also returns to its initial position (see Figure 9). Accordingly, the ring member 34 and the ratchet 37 also return to their initial positions (see Figure 11(a) if the gap is less than the specified value, and Figure 11(d) if the gap is greater than or equal to the specified value). Note that when the ratchet 37 returns to its initial position, the pawl 371 slides along the tooth tip without engaging with the tooth 331, so the ratchet gear 33 does not rotate.

[0073] As can be understood from the above explanation, in a disc brake system, the amount of axial outward movement of the cam holder 13, and consequently the amount of rotation of the second lever 36, is determined by the gap between the disc rotor 1 and the brake pad 3 during braking. In other words, the amount of rotation of the adjuster nut 31, which is linked to the rotation of the second lever 36, is also determined according to the above gap. Furthermore, frictional resistance is generated between the adjuster nut 31 and the spindle 32 due to the pressing force generated during braking, and this frictional resistance restricts the rotation of the adjuster nut 31, so that gap adjustment due to pad wear and deformation of the cylinder body is not performed during braking. Therefore, in a disc brake system, the spindle 32 is moved axially outward by the necessary amount relative to the adjuster nut 31 according to the above gap, so that the gap is adjusted appropriately and over-adjustment is prevented.

[0074] <Operation and Effects> According to this embodiment, when the cam holder 13, and consequently the adjuster nut 31 and spindle 32 move in the axial direction, the cam holder 13 is guided by the anchor plate 14 on the axially inward side, and the adjuster nut 31 is guided by the guide plate 16 on the axially outward side. As a result, the pad pressing mechanism 4 is properly positioned and can move smoothly in the axial direction.

[0075] According to this embodiment, the pair of bolts 22 can properly guide the axial movement of the cam holder 13.

[0076] According to this embodiment, when not braking, and especially when the brake is released, the cam holder return spring 17 can return the cam holder 13, and consequently the adjuster nut 31 and spindle 32, to their initial positions.

[0077] According to this embodiment, the roller 112 reduces friction between the push rod 7 and the cam lever unit 11, thereby suppressing energy loss related to thrust from the air cylinder 6.

[0078] According to this embodiment, the cam lever unit 11 is composed of multiple components (cam lever 111 and roller 112), which improves design flexibility and maintainability.

[0079] According to this embodiment, the bearing 21 reduces friction between the eccentric portion 122 and the anchor plate 14, thereby suppressing the energy loss related to the force amplification described above.

[0080] According to this embodiment, the guide holes 5a and 142 can properly guide the axial movement of the cam holder 13.

[0081] According to this embodiment, the horizontal guide surface 141 can properly guide the axial movement of the cam holder 13.

[0082] According to this embodiment, the anchor plate 14 is securely fixed to the cylinder body 5 by being fitted into the fitting groove 5b of the cylinder body 5, thereby enabling more appropriate and stable guidance of the axial movement of the cam holder 13.

[0083] According to this embodiment, during braking, the amount of axial outward movement of the cam holder 13, and consequently the amount of rotation of the second lever 36, is determined according to the gap between the disc rotor 1 and the brake pad 3. In other words, the amount of rotation of the adjuster nut 31, which is linked to the rotation of the second lever 36, is also determined according to the gap. Therefore, according to this embodiment, since the spindle 32 is moved axially outward according to the gap, the size of the gap can be adjusted with high precision.

[0084] According to this embodiment, by fixing the ratchet 37 to the ring member 34, the ratchet gear 33 can be rotated with high precision according to the amount of rotation of the second lever 36.

[0085] According to this embodiment, the gap adjustment mechanism 15 has a spring 38, which allows the second lever 36 to be rotated more appropriately when gap adjustment is necessary during braking.

[0086] According to this embodiment, the gap adjustment mechanism 15 has a regulating spring 40, and the frictional resistance between the adjuster nut 31 and the cam holder 13, which is generated by the biasing force of the regulating spring 40 on the adjuster nut 31, can restrict the rotation of the adjuster nut 31 when not braking.

[0087] According to this embodiment, the ratchet 37 is positioned approximately opposite the first lever 35 in the radial direction, straddling the central axis O of the adjuster nut 31. This allows for a miniaturization of the gap adjustment mechanism 15 compared to the case where the ratchet 37 is located at the same position as the first lever 35.

[0088] According to this embodiment, frictional resistance is generated between the adjuster nut 31 and the spindle 32 due to the pressing force generated during braking. This frictional resistance restricts the rotation of the adjuster nut 31, preventing gap adjustments caused by pad wear and deformation of the cylinder body during braking, thus preventing over-adjustment and the like.

[0089] [First Modified Example] The difference between the first modified example and the above embodiment lies in a part of the gap adjustment mechanism. In the following, only this difference will be explained, and identical components will be denoted by the same reference numerals, and explanations will be omitted as much as possible.

[0090] The gap adjustment mechanism of the first modified example, as shown in Figure 12, comprises an adjuster nut 31, a spindle 32, a ratchet gear 33, a second lever 36, a spring 38, and a regulating spring 40 (not shown). Since these components are the same as those of the gap adjustment mechanism 15 of the above embodiment, their description is omitted.

[0091] Furthermore, the gap adjustment mechanism of the first modified example includes a slide plate 51 on which a projection 52 held by the second lever 36 is provided, and a ratchet 53 fixed to the slide plate 51, which meshes with a ratchet gear 33 and rotates the ratchet gear 33 in response to the sliding of the slide plate 51.

[0092] The slide plate 51 is attached to the cam holder 13 so as to be slidable in the width direction. The projection 52 protrudes radially (upward in Figure 12) from the nut body 312 and is formed in a hollow shape, with the fitting portion 531 of the ratchet 53 fitted inside the hollow portion 521 of the projection 52.

[0093] The ratchet 53 has a fitting portion 531 that protrudes radially (upward in Figure 12) from the nut body portion 312, and the fitting portion 531 is fitted into the hollow portion 521 of the projection 52, thereby enabling it to slide together with the slide plate 51. The ratchet 53 has a pawl 532 that engages with the teeth 331 of the ratchet gear 33. The pawl 532 of the ratchet 53 is engaged with the teeth 331 of the ratchet gear 33 even when the disc brake device is not braking.

[0094] Here, the gap adjustment mechanism configured as described above operates as follows. In the following explanation, we will describe two cases as examples: when the gap between the disc rotor 1 and the brake pad 3 is less than a specified value, and when the gap is greater than or equal to a specified value. Also, as described above, the gap adjustment by the gap adjustment mechanism 15 is performed during braking and before the spindle 32 presses the brake pad 3 against the rotor surface 1a.

[0095] When the disc brake system is applied, as described above, the cam holder 13 moves axially outward, and the axially inward end face of the cam holder 13, which was in contact with the anchor plate 14 when not braking, separates from the anchor plate 14. Then, due to the biasing force of the spring 38, the second lever 36 rotates counterclockwise in Figure 9, even though the rotation restricting portion 363 of the second lever 36 is in contact with the anchor plate 14.

[0096] Next, since the projection 52 of the slide plate 51 is held by the holding portion 362 of the second lever 36, when the second lever 36 is rotated, the slide plate 51 slides to the right in Figure 12 in conjunction with the rotation of the second lever 36. At this time, the ratchet 53 fixed to the slide plate 51 also slides to the right in Figure 12 along with the slide plate 51.

[0097] Next, if the gap between the disc rotor 1 and the brake pad 3 is less than the specified value, the amount of sliding of the ratchet 53, that is, the amount of rotation of the second lever 36, will not cause the ratchet gear 33 to rotate. Therefore, the adjuster nut 31 will not rotate, and the spindle 32 will not move axially outward relative to the adjuster nut 31, that is, the gap will not be adjusted, and the brake pad 3 will be pressed against the rotor surface 1a.

[0098] On the other hand, if the gap between the disc rotor 1 and the brake pad 3 is greater than the specified value, the sliding of the ratchet 53 causes the pawl 532 to push the teeth 331, and the ratchet gear 33 rotates clockwise in Figure 12. Consequently, the adjuster nut 31 also rotates clockwise in Figure 12, and the spindle 32 moves axially outward relative to the adjuster nut 31, completing the gap adjustment. In other words, after the gap adjustment, the spindle 32 protrudes axially outward by the amount of the adjustment compared to before the gap adjustment. Then, after the gap adjustment is completed, the brake pad 3 is pressed against the rotor surface 1a by the spindle 32.

[0099] Subsequently, when the braking force of the disc brake device is released, the cam holder 13 returns to its initial position, and as a result, the second lever 36 also returns to its initial position, and accordingly, the slide plate 51 and the ratchet 53 also return to their initial positions. Note that when the ratchet 53 returns to its initial position, the pawl 532 slides along the tooth tips without engaging with the teeth 331, so the ratchet gear 33 does not rotate.

[0100] As can be understood from the above explanation, in the disc brake device of this example, during braking, the amount of axial outward movement of the cam holder 13, and consequently the amount of rotation of the second lever 36, is determined according to the gap between the disc rotor 1 and the brake pad 3. In other words, the amount of rotation of the adjuster nut 31, which is linked to the rotation of the second lever 36, is also determined according to the gap. Therefore, according to the first modified example, since the spindle 32 is moved axially outward according to the gap, the size of the gap can be adjusted with high precision.

[0101] [Second Modification] As shown in Figure 13, the disc brake device may have the cam holder return spring 17 arranged coaxially with the pair of bolts 22. This reduces the number of parts and allows for miniaturization of the disc brake device.

[0102] <Other Embodiments> The present invention is not limited to the embodiments described above, and can be modified, improved, etc. as appropriate. Furthermore, the material, shape, dimensions, number, placement, etc. of each component in the embodiments described above are arbitrary and not limited as long as they can achieve the present invention.

[0103] In the above embodiment, the anchor plate 14 is provided with a horizontal guide surface 141, but for example, the anchor plate 14 does not necessarily have to be provided with a horizontal guide surface 141.

[0104] In the above embodiment, the ratchet 37 is positioned approximately opposite the first lever 35 in the radial direction (vertical direction in Figure 8) of the adjuster nut 31, with the central axis O of the adjuster nut 31 in between. However, for example, it may be positioned at the same location in the circumferential direction of the adjuster nut 31, or it may simply be positioned offset.

[0105] <Note> Hereinafter, the features of the embodiments of the disc brake device of the present disclosure described above are briefly summarized below. [1] A disc brake device comprising: a disc rotor (1) that rotates with the wheel; a brake pad (3) provided opposite to the rotor surface (1a) of the disc rotor (1); a pad pressing mechanism (4) for pressing the brake pad (3) against the rotor surface (1a); and a cylinder body (5) housing the pad pressing mechanism (4), wherein the disc rotor (1) is braked by pressing the brake pad (3) against the rotor surface (1a) with the pad pressing mechanism (4), the pad pressing mechanism (4) comprising: a cam lever unit (11) having an eccentric camshaft (12); a cam holder (13) that pivotally supports the camshaft (12) so that the cam lever unit (11) can rotate around the camshaft (12), and is movable in the axial direction on the disc rotor (1), The device comprises: an adjuster nut (31) located axially outward on the disc rotor (1) from the cam holder (13) and having a fitting portion (311) that fits into the cam holder (13); a spindle (32) that screws into the adjuster nut (31) and presses the brake pad (3) against the rotor surface (1a); an anchor plate (14) attached to the cylinder body (5) axially inward on the disc rotor (1) from the cam holder (13) and guiding the axial movement of the cam holder (13); and a guide plate (16) fixed to the axially outward end of the cylinder body (5) and having a hole (161) into which the adjuster nut (31) is inserted, and guiding the axial movement of the adjuster nut (31). The camshaft (12) is a disc brake device that, during braking, multiplies the force transmitted by the rotation of the cam lever unit (11) to move the cam holder (13) outward in the axial direction.[2] The disc brake device described in [1] above, wherein the cam holder (13) has a flange portion (131) through which a pair of holes (131a) are provided, through which a pair of bolts (22) for fixing the guide plate (16) to the cylinder body (5) are respectively inserted. [3] The disc brake device described in [1] or [2] above, wherein the pad pressing mechanism (4) has a cam holder return spring (17) that biases the cam holder (13) to return to its initial position when not braking. [4] The disc brake device described in [3] above, wherein the cam holder return spring (17) is arranged coaxially with a pair of bolts (22) for fixing the guide plate (16) to the cylinder body (5). [5] A disc brake device according to any one of [1] to [4] above, further comprising an air cylinder (6) housing a push rod (7) that moves forward by air pressure, wherein the cam lever unit (11) has a roller (112) supported by a guide groove (7a) at the tip of the push rod (7) and to which thrust from the air cylinder (6) is transmitted. [6] A disc brake device according to [5] above, wherein the cam lever unit (11) further comprises a pair of cam levers (111) that hold the cam shaft (12), and the roller (112) is disposed between the pair of cam levers (111). [7] A disc brake device according to any one of [1] to [6] above, wherein the camshaft (12) is composed of a cylindrical cam body (121) and a pair of eccentric portions (122) provided at both ends of the cam body (121) in the extending direction and eccentric to the cam body (121), and the eccentric portions (122) are provided with bearings (21) that are in contact with the anchor plate (14), the disc brake device.[8] A disc brake device according to any one of [1] to [7] above, wherein the cam holder (13) is provided with a boss portion (133) that protrudes inward in the axial direction, and the boss portion (133) is inserted through a guide hole (142) provided in the anchor plate (14) and a guide hole (5a) provided in the cylinder body (5). [9] A disc brake device according to any one of [1] to [8] above, wherein the anchor plate (14) has a horizontal guide surface (141) that extends in the axial direction and guides the axial movement of the cam holder (13).

[10] A disc brake device according to any one of [1] to [9] above, wherein the cylinder body (5) is provided with a fitting groove (5b) into which the anchor plate (14) is fitted.

[0106] This application is based on Japanese Patent Application No. 2024-184064 filed on October 18, 2024, and its contents are incorporated herein by reference.

[0107] The technology disclosed herein is useful as a disc brake device in which a pad pressing mechanism for pressing a brake pad against the rotor surface of a disc rotor is properly positioned and can move smoothly in the axial direction of the disc rotor.

[0108] 1 Disc rotor 1a Rotor surface 3 Brake pad 4 Pad pressing mechanism 5 Cylinder body 5a Guide hole 6 Air cylinder 7 Push rod 7a Guide groove 11 Cam lever unit 12 Camshaft 13 Cam holder 14 Anchor plate 15 Gap adjustment mechanism 16 Guide plate 17 Cam holder return spring 21 Bearing 22 Bolt 31 Adjuster nut 32 Spindle 33 Ratchet gear 34 Ring member 35 First lever 36 Second lever 37, 53 Ratchet 38 Spring 40 Restricting spring 51 Slide plate 52 Protrusion 111 Cam lever 112 Roller 121 Cam body 122 Eccentric part 131 Flange part 131a Hole part 133 Boss part 141 Horizontal guide surface 142 Guide hole 161 Hole 311 Fitting part 361 Rotation center 363 Rotation restricting part

Claims

1. A disc brake device comprising: a disc rotor that rotates with the wheel; a brake pad provided opposite the rotor surface of the disc rotor; a pad pressing mechanism for pressing the brake pad against the rotor surface; and a cylinder body housing the pad pressing mechanism, wherein the disc brake device brakes the disc rotor by pressing the brake pad against the rotor surface using the pad pressing mechanism, the pad pressing mechanism comprising: a cam lever unit having an eccentric camshaft; a cam holder that pivotally supports the camshaft so that the cam lever unit can rotate around the camshaft and is movable in the axial direction on the disc rotor; an adjuster nut located axially outward on the disc rotor from the cam holder and having a fitting portion fitted into the cam holder; a spindle that screws into the adjuster nut and presses the brake pad against the rotor surface; and an anchor plate attached to the cylinder body axially inward on the disc rotor from the cam holder and guiding the axial movement of the cam holder. A disc brake device comprising: a guide plate fixed to the axially outer end of the cylinder body, having a hole into which the adjuster nut is inserted, and guiding the axial movement of the adjuster nut, wherein the camshaft, during braking, amplifies the force transmitted by the rotation of the cam lever unit to move the cam holder axially outward.

2. A disc brake device according to claim 1, wherein the cam holder has a flange portion provided with a pair of holes through which a pair of bolts for fixing the guide plate to the cylinder body are each inserted.

3. A disc brake device according to claim 1, wherein the pad pressing mechanism has a cam holder return spring that biases the cam holder to return to its initial position when not braking.

4. A disc brake device according to claim 3, wherein the cam holder return spring is arranged coaxially with a pair of bolts for fixing the guide plate to the cylinder body.

5. A disc brake device according to claim 1, further comprising an air cylinder housing a push rod that moves forward by pneumatics, wherein the cam lever unit has a roller supported by a guide groove at the tip of the push rod and to which thrust from the air cylinder is transmitted.

6. A disc brake device according to claim 5, wherein the cam lever unit further comprises a pair of cam levers for holding the cam shaft, and the roller is disposed between the pair of cam levers.

7. A disc brake device according to claim 1, wherein the camshaft is composed of a cylindrical cam body and a pair of eccentric portions provided at both ends of the cam body in the extending direction and eccentric to the cam body, and the eccentric portions are provided with bearings that are in contact with an anchor plate.

8. A disc brake device according to claim 1, wherein the cam holder is provided with a boss portion that protrudes inward in the axial direction, and the boss portion is inserted through a guide hole provided in the anchor plate and a guide hole provided in the cylinder body.

9. A disc brake device according to claim 1, wherein the anchor plate has a horizontal guide surface that extends in the axial direction and guides the axial movement of the cam holder.

10. A disc brake device according to claim 1, wherein the cylinder body is provided with a fitting groove into which the anchor plate is fitted.

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