Caliper for facing piston type disc brake

Abstract

To realize a caliper for a facing piston type disc brake which secures rigidity and achieves reduction of the weight.SOLUTION: A band-like outer side reinforcement rib 17b is provided at an outer body 6 forming a caliper 2. The outer side reinforcement rib 17b is connected at both circumferential ends to a turn-in side connection part 7 and a turn-out side connection part 8 and covers bottom portions 16a, 16b, 16c of outer cylinder portions 14a, 14b, 14c from an axially outer side so as to cross the bottom portions 16a, 16b, 16c in a circumferential direction. Bottomed cut-out portions 18a, 18b recessed in an axial direction are provided on circumferentially outer side portions of the outer side reinforcement rib 17b.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a caliper that constitutes an opposed-piston disc brake device. [Background technology]

[0002] Disc brake devices are widely used to brake automobiles and motorcycles. When a disc brake device applies braking, a pair of pads, located on both axial sides of a rotor that rotates with the wheel, are pressed against both axial surfaces of the rotor by a piston. While various structures of such disc brake devices have been known, opposed-piston disc brake devices, which have pistons on both axial sides of the rotor, have been increasingly used in recent years because they can provide stable braking force.

[0003] The opposed-piston disc brake device comprises a caliper fixed to the vehicle body and positioned to cover the rotor, which rotates with the wheel, from the radial outside, and a pair of pads supported so as to be able to move axially relative to the caliper and positioned on both axial sides of the rotor.

[0004] A caliper constituting a disc brake device for an automobile has an inner body arranged axially inside the rotor, an outer body arranged axially outside the rotor, and a rotation-in side connecting portion and a rotation-out side connecting portion arranged radially outside the outer peripheral edge of the rotor and connecting both outer circumferential ends of the inner body to both outer circumferential ends of the outer body.

[0005] The inner body has an inner cylinder portion into which an inner piston is fitted, the inner cylinder portion opening on an axially outer surface of the inner body facing the rotor, and the outer body has an outer cylinder portion into which an outer piston is fitted, the outer cylinder portion opening on an axially inner surface of the outer body facing the rotor.

[0006] During braking, brake fluid is pumped from the master cylinder into both the inner and outer cylinders. This pushes the inner piston fitted into the inner cylinder in the axial direction, pressing the pads supported by the inner body against the axially inner surface of the rotor. Similarly, the outer piston fitted into the outer cylinder is pushed in the axial direction, pressing the pads supported by the outer body against the axially outer surface of the rotor. As a result, the rotor is tightly clamped from both axial sides by the pair of pads, braking the vehicle.

[0007] During braking, the inner and outer pistons press the pair of pads against both axial sides of the rotor, and as a reaction, a force is applied to the inner and outer bodies in an axial direction that moves them away from each other. Therefore, if the caliper does not have sufficient rigidity, the inner and outer bodies may elastically deform in the axial direction and move away from each other, which could result in an inability to achieve the desired braking force. Furthermore, if the caliper does not have sufficient rigidity, the outer body may elastically deform in the direction of rotor rotation relative to the inner body during braking, which could cause vibration and noise.

[0008] In view of these circumstances, for example, JP 2012-514166 A (Patent Document 1) discloses a structure in which a band-shaped (strip-shaped) reinforcing rib is provided on the axially outer side of the outer body. Specifically, in the conventional structure described in JP 2012-514166 A, a band-shaped reinforcing rib is provided to connect both circumferentially outer ends of the inlet-side connecting portion and the outlet-side connecting portion, respectively, and the reinforcing rib covers the bottoms of the two outer cylinder portions provided on the outer body from the axially outer side. This conventional structure improves the rigidity of the outer body, which is advantageous in terms of obtaining the desired braking force and suppressing the generation of vibration and noise. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Special Publication No. 2012-514166 Summary of the Invention [Problem to be solved by the invention]

[0010] Since the disc brake device is located closer to the road surface than the springs that make up the suspension system of the vehicle, it is subject to what is known as an unsprung load. For this reason, there is a demand for reducing the weight of the calipers that make up the disc brake device in order to improve the fuel efficiency and driving performance of the vehicle. However, the conventional structure described in JP 2012-514166 A still has room for improvement in terms of achieving both rigidity and weight reduction.

[0011] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a caliper for an opposed-piston disc brake that can ensure both rigidity and weight reduction. [Means for solving the problem]

[0012] The caliper for an opposed-piston type disc brake of the present invention comprises an inner body, an outer body, a rotation-inlet side connecting portion, and a rotation-outlet side connecting portion. The inner body has an inner cylinder portion and is disposed axially inside the rotor. The outer body has an outer cylinder portion and is disposed axially outward of the rotor. The inlet side connecting portion and the outlet side connecting portion are positioned radially outward from the outer peripheral edge of the rotor, and axially connect the two outer circumferential ends of the inner body and the two outer circumferential ends of the outer body. The outer body has band-shaped reinforcing ribs whose outer circumferential ends are connected to the inlet side connecting portion and the outlet side connecting portion, and which cover the bottom of the outer cylinder portion from the axial outside, crossing the circumferential direction. The reinforcing rib has, on at least one of both circumferentially outer portions, a notched portion recessed in the axial direction and having a bottom or no bottom, that is, a notched portion that opens outward in the axial direction.

[0013] In the opposed-piston disc brake caliper according to one aspect of the present invention, the recessed portion may have a shape that is long in the circumferential direction, and the reinforcing rib may have side ribs that extend in the circumferential direction on both radial sides of the recessed portion. Also, the caliper may have a total of two or more side ribs.

[0014] In the opposed-piston disc brake caliper according to one aspect of the present invention, each of the side ribs may extend in a direction approaching the central axis of the outer cylinder portion as it moves circumferentially inward.

[0015] In an opposed-piston disc brake caliper according to one aspect of the present invention, the recessed portion may be provided at a radially intermediate portion of the reinforcing rib, and the side ribs arranged radially outward from the recessed portion may be inclined radially inward as they move circumferentially inward, and the side ribs arranged radially inward from the recessed portion may be inclined radially outward as they move circumferentially inward. In this case, the side rib arranged radially inside the undercut portion can be connected to the circumferentially outer end of the inlet-side connecting portion or the outlet-side connecting portion.

[0016] In an opposed-piston disc brake caliper according to one aspect of the present invention, the radial thickness of the side rib arranged radially outside the undercut portion can be made larger than the radial thickness of the side rib arranged radially inside the undercut portion.

[0017] In an opposed-piston type disc brake caliper according to one aspect of the present invention, when viewed from the radial outside, the side rib arranged radially inside the undercut portion can be made to protrude outward from the side rib arranged radially outside the undercut portion.

[0018] In one aspect of the caliper for opposed-piston disc brakes of the present invention, the reinforcing rib has a flat design surface on the circumferential inner portion formed by the axial outer surface of the reinforcing rib, and the design surface and the axial outer surface of the side rib can be smoothly connected without any steps.

[0019] In the opposed-piston disc brake caliper according to one aspect of the present invention, the axially outer side surfaces of the side ribs can be inclined in a direction that moves axially inward as they move outward in the circumferential direction.

[0020] In the opposed-piston disc brake caliper according to one aspect of the present invention, at least one of the side ribs may have a communication passage therein for passing brake oil.

[0021] In an opposed-piston disc brake caliper according to one aspect of the present invention, the reinforcing rib may have one cutout portion at a radially intermediate portion on each of both circumferentially outer sides thereof, and each cutout portion may have a generally triangular shape in an axial view, with the radial width increasing toward the circumferentially outer side. Furthermore, the reinforcing rib, excluding the cutout portion, may have a generally X-shape in an axial view. In this case, the axial thickness of the reinforcing rib excluding the undercut portion can be made larger in the portion that is circumferentially outward from the outer cylinder portion than in the portion that covers the bottom of the outer cylinder portion.

[0022] In the opposed-piston disc brake caliper according to one aspect of the present invention, the undercut portion may have a bottom, that is, may be a recess (bottomed hole). Alternatively, the recessed portion may be formed without a bottom, that is, as a through hole. [Effects of the Invention]

[0023] According to the opposed-piston disc brake caliper of the present invention, it is possible to ensure both rigidity and weight reduction. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a plan view of an opposed-piston disc brake device according to an embodiment, as viewed from the radially outer side. [Figure 2] FIG. 2 is a front view of a caliper taken out from an opposed-piston disc brake device according to a first example of the embodiment, as viewed from the axially outer side. [Figure 3] FIG. 3 is a rear view of a caliper taken out from an opposed-piston disc brake device according to a first example of the embodiment, as viewed from the axially inner side. [Figure 4] FIG. 4 is an end view of a caliper taken out from an opposed-piston disc brake device according to a first example of the embodiment, viewed from the rotation-in side. [Figure 5] FIG. 5 is an end view of a caliper taken out from an opposed piston type disc brake device according to a first example of the embodiment, as viewed from the rotation side. [Figure 6] FIG. 6 is a bottom view of a caliper taken out from an opposed-piston disc brake device according to a first example of the embodiment, as viewed from the inside in the radial direction. [Figure 7] FIG. 7 is a perspective view showing a caliper taken out from an opposed-piston disc brake device according to a first example of the embodiment. [Figure 8] FIG. 8 is a perspective view of a caliper taken out from an opposed-piston disc brake device according to a first example of the embodiment, as viewed from the radially outer side. [Figure 9] FIG. 9 is a diagram corresponding to FIG. 2 and showing a second example of the embodiment. [Figure 10] FIG. 10 is a diagram corresponding to FIG. 2 and shows a third example of the embodiment. [Figure 11] FIG. 11 is a diagram corresponding to FIG. 2 and shows a fourth example of the embodiment. [Figure 12] FIG. 12 is a diagram corresponding to FIG. 7 and shows a fourth example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0025] [First example of embodiment] A first example of the embodiment will be described with reference to FIGS.

[0026] The opposed-piston disc brake device 1 of this example is used for automobiles, and includes a caliper 2 and a pair of pads 3 (an inner pad and an outer pad).

[0027] In this specification and claims, unless otherwise specified, the terms "axial direction," "circumferential direction," and "radial direction" refer to the axial, circumferential, and radial directions of the disk-shaped rotor 4 (see FIG. 1). Additionally, the inner circumferential side refers to the circumferential center side of the opposed-piston disc brake device 1, and the outer circumferential side refers to both circumferential sides of the opposed-piston disc brake device 1. Additionally, the rotation-in side refers to the outer circumferential side where the rotor 4, which rotates together with the wheel when the vehicle is moving forward, enters the inside of the caliper 2, and the rotation-out side refers to the outer circumferential side where the rotor 4 exits the caliper 2.

[0028] Caliper The caliper 2 is arranged to cover the rotor 4 from the radial outside, and supports a pair of pads 3 so that they can move in the axial direction (up and down in Figures 1, 6 and 8, front and back in Figures 2 and 3, left and right in Figures 4 and 5), and is formed integrally by forging or other processing using a light alloy such as an aluminum alloy or an iron-based alloy material.

[0029] The caliper 2 has an overall boat-like shape and is generally bow-shaped when viewed in the axial direction. The caliper 2 includes an inner body 5 and an outer body 6 arranged to sandwich the rotor 4 from both sides in the axial direction, and a rotation-inlet-side connecting portion 7 and a rotation-outlet-side connecting portion 8 that axially connect the outer circumferential ends of the inner and outer bodies 5, 6.

[0030] Inner Body The inner body 5 is disposed axially inside the rotor 4. The inner body 5 includes three inner cylinder portions 9a, 9b, and 9c and two mounting holes 10a and 10b.

[0031] The three inner cylinder portions 9a, 9b, and 9c are arranged spaced apart in the circumferential direction. Each of the inner cylinder portions 9a, 9b, and 9c is cylindrical with a bottom and has a substantially cylindrical cylinder space therein. An inner piston (not shown) is fitted into each cylinder space of the inner cylinder portions 9a, 9b, and 9c so that it can move in the axial direction. Each of the inner cylinder portions 9a, 9b, and 9c is arranged on the circumferential inner side of the inner body 5 and opens to the axial outer surface of the inner body 5 that faces the rotor 4.

[0032] Part of the outer contour of the bottomed cylindrical inner cylinder portions 9a, 9b, and 9c is visible in the inner body 5. Specifically, as shown in FIG. 1, outer peripheral portions of the tubular portions 11a, 11b, and 11c that constitute the inner cylinder portions 9a, 9b, and 9c are visible on the radially outer surface of the inner body 5. Furthermore, as shown in FIG. 6, inner peripheral portions of the tubular portions 11a, 11b, and 11c that constitute the inner cylinder portions 9a, 9b, and 9c are visible on the radially inner surface of the inner body 5. Furthermore, as shown in FIG. 3, circular bottom portions 12a, 12b, and 12c that constitute the inner cylinder portions 9a, 9b, and 9c are visible on the axially inner surface of the inner body 5.

[0033] In the illustrated example, the cylinder diameters of the three inner cylinder portions 9a, 9b, and 9c are different from one another. Specifically, the cylinder diameter of the inner cylinder portion 9a located on the inflow side is the smallest, and the cylinder diameter of the inner cylinder portion 9c located on the outflow side is the largest.

[0034] The two mounting holes 10a, 10b are arranged on both circumferentially outer sides of the inner body 5 so as to sandwich the three inner cylinder portions 9a, 9b, 9c from both sides in the circumferential direction. The caliper 2 is fixed to a knuckle that constitutes a suspension system of the vehicle body using bolts (not shown) that are inserted radially outward through the mounting holes 10a, 10b, either directly or via an adapter (not shown). Therefore, the caliper 2 in this example is a radially mounted caliper.

[0035] An inner-side reinforcing rib 13 is provided on the axially inner side of the inner body 5. The inner-side reinforcing rib 13 is a thick portion that is thicker than other portions and protrudes axially inward. Therefore, the inner body 5 has an increased thickness at the portion where the inner-side reinforcing rib 13 is provided, improving its rigidity.

[0036] The inner-side reinforcing rib 13 is configured as a band extending in the circumferential direction, and both outer circumferential ends are connected to the inlet-side connecting part 7 and the outlet-side connecting part 8. The inner-side reinforcing rib 13 circumferentially crosses the bottom parts 12a, 12b, 12c that make up the inner cylinder parts 9a, 9b, 9c, covering them from the axially inner side.

[0037] The inner body 5 movably supports the inner pads 3 arranged axially inside the rotor 4. For this purpose, the inner body 5 has inner-side protrusions 28 that protrude in the axial direction on both circumferential outer sides of the axially outer surface.

[0038] Outer Body The outer body 6 is disposed axially outside the rotor 4. The outer body 6 includes three outer cylinder portions 14a, 14b, and 14c.

[0039] The three outer cylinder portions 14a, 14b, and 14c are arranged spaced apart in the circumferential direction. Each of the outer cylinder portions 14a, 14b, and 14c is cylindrical with a bottom and has a substantially cylindrical cylinder space therein. An outer piston (not shown) is fitted into each cylinder space of the outer cylinder portions 14a, 14b, and 14c so as to be displaceable in the axial direction. Each of the outer cylinder portions 14a, 14b, and 14c is arranged on the circumferential inner side of the outer body 6 and opens to the axial inner surface of the outer body 6 that faces the rotor 4.

[0040] Part of the outer contour of the bottomed cylindrical outer cylinder portions 14a, 14b, 14c is visible in the outer body 6. Specifically, as shown in Fig. 1, outer peripheral portions of the tubular portions 15a, 15b, 15c that constitute the outer cylinder portions 14a, 14b, 14c are visible on the radially outer surface of the outer body 6. Furthermore, as shown in Fig. 6, inner peripheral portions of the tubular portions 15a, 15b, 15c that constitute the outer cylinder portions 14a, 14b, 14c are visible on the radially inner surface of the outer body 6. Furthermore, as shown in Fig. 2, circular bottom portions 16a, 16b, 16c that constitute the outer cylinder portions 14a, 14b, 14c are visible on the axially outer surface of the outer body 6.

[0041] In the illustrated example, the cylinder diameters of the three outer cylinder portions 14a, 14b, and 14c are different from one another. Specifically, the cylinder diameter of the outer cylinder portion 14a located on the inflow side is the smallest, and the cylinder diameter of the outer cylinder portion 14c located on the outflow side is the largest.

[0042] The outer cylinder portions 14a, 14b, and 14c are arranged coaxially with the inner cylinder portions 9a, 9b, and 9c, respectively.

[0043] An outer reinforcing rib 17 is provided on the axially outer side of the outer body 6. The outer reinforcing rib 17 is thicker than other parts and is a thick portion that bulges outward in the axial direction. Therefore, the outer body 6 has an increased thickness in the part where the outer reinforcing rib 17 is provided, improving its rigidity. In this example, the outer reinforcing rib 17 corresponds to the reinforcing rib described in the claims.

[0044] The outer reinforcing rib 17 is configured in the shape of a band extending in the circumferential direction, and both outer circumferential ends are connected to the inlet connecting part 7 and the outlet connecting part 8. The outer reinforcing rib 17 circumferentially crosses the bottom parts 16a, 16b, 16c that make up the outer cylinder parts 14a, 14b, 14c, covering them from the outside in the axial direction.

[0045] The radially outer surface of the outer reinforcing rib 17 is a partial cylindrical surface that is slightly curved in an arc so that the radially inward side is convex. In contrast, the radially inner surface of the circumferentially inner part of the outer reinforcing rib 17 is also a partial cylindrical surface that is curved in an arc so that the radially outward side is convex. For this reason, the radial width of the circumferentially inner part of the outer reinforcing rib 17 decreases from the circumferentially outer side toward the circumferentially inner side, and is smallest at the part that covers the bottom 16b of the outer cylinder part 14b located in the circumferential middle.

[0046] The outer reinforcing rib 17 has two cutouts (lightening holes) 18a, 18b recessed in the axial direction at the radially middle portions of both circumferentially outer portions. In this example, each of the cutouts 18a, 18b is a recess with a bottom.

[0047] Each of the cutout portions 18a, 18b has a circumferentially elongated shape with a circumferential width greater than its radial width. Specifically, each of the cutout portions 18a, 18b has a substantially triangular shape when viewed in the axial direction. The radial width of each of the cutout portions 18a, 18b increases toward the outer circumferential side.

[0048] The cutout portion 18a arranged on the rotation-in side is open to the axially outer side and the circumferentially outer side (the rotation-in side), respectively. The cutout portion 18b arranged on the rotation-out side is open to the axially outer side and the circumferentially outer side (the rotation-out side), respectively.

[0049] In the illustrated example, the circumferentially inner corner (end) of the cutout portion 18a arranged on the inlet side is located circumferentially outward of the outer cylinder portion 14a arranged on the inlet side and is configured with a concave curved surface to prevent stress concentration. Similarly, the circumferentially inner corner of the cutout portion 18b arranged on the outlet side is located circumferentially outward of the outer cylinder portion 14c arranged on the outlet side and is also configured with a concave curved surface. However, when implementing the present invention, the circumferentially inner corners of the cutout portions arranged on the inlet side and outlet side can be positioned so as to overlap the bottom of the outer cylinder portion, or can be configured with a corner rather than a concave curved surface.

[0050] The band-shaped outer reinforcing rib 17 of this example has a radially outer surface curved so that the radially inner side is convex, and a radially inner surface curved so that the radially outer side is convex, and is provided with cutout portions 18a, 18b that are approximately triangular in shape when viewed in the axial direction at the radially middle portions of both circumferential outer portions. Therefore, both circumferential outer portions of the outer reinforcing rib 17 have a bifurcated shape, and the outer reinforcing rib 17 as a whole has a approximately X-shape when viewed in the axial direction.

[0051] The axial thickness of the outer reinforcing rib 17 is not constant in the circumferential direction but varies depending on the circumferential position. Specifically, the axial thickness of the outer reinforcing rib 17 excluding the cutouts 18a, 18b is greater in the portions circumferentially outwardly spaced from the bottoms 16a, 16b, 16c of the outer cylinder portions 14a, 14b, 14c than in the portions covering the bottoms 16a, 16b, 16c of the outer cylinder portions 14a, 14b, 14c.

[0052] The outer-side reinforcing rib 17 has two side ribs 19a, 19b on either radial side of the cutout portion 18a located on the inlet side, and two side ribs 20a, 20b on either radial side of the cutout portion 18b located on the outlet side. The outer-side reinforcing rib 17 also has one center rib 21 between the two side ribs 19a, 19b located on the inlet side and the two side ribs 20a, 20b located on the outlet side. Therefore, the outer-side reinforcing rib 17 in this example is made up of one center rib 21 that forms the circumferential inner side of the outer-side reinforcing rib 17, and a total of four side ribs 19a, 19b, 20a, 20b that form both circumferential outer sides of the outer-side reinforcing rib 17.

[0053] Of the two side ribs 19a, 19b arranged on the return side, the circumferentially outer end of the side rib 19a arranged radially outside the cutout portion 18a is connected to the circumferentially inner portion of the return-side connecting portion 7. The circumferentially inner end of the side rib 19a is connected to the circumferentially outer end of the radially outer portion of the center rib 21. In contrast, of the two side ribs 19a, 19b, the circumferentially outer end of the side rib 19b arranged radially inside the cutout portion 18a is located circumferentially outer than the circumferentially outer end of the side rib 19a and is connected to the circumferentially outer end of the return-side connecting portion 7. The circumferentially inner end of the side rib 19b is connected to the circumferentially outer end of the radially inner portion of the center rib 21 at approximately the same circumferential position (position X1) as the circumferentially inner end of the side rib 19a. When carrying out the present invention, the circumferentially inner portions of the side ribs may be connected to the circumferentially outer ends of the center ribs and directly connected to the cylindrical portion of the outer cylinder portion on the inlet side.

[0054] The two side ribs 19a, 19b have slightly different radial thicknesses. Specifically, at the same circumferential position, the radial thickness of the side rib 19a located radially outside the cutout portion 18a is slightly greater than the radial thickness of the side rib 19b located radially inside the cutout portion 18a. Also, as shown in FIG. 1 , when the caliper 2 is viewed from the radial outside, a portion of the side rib 19b located radially inside the cutout portion 18a slightly protrudes outward from the side rib 19a located radially outside the cutout portion 18a. When implementing the present invention, a majority of the side rib located radially inside the cutout portion can also protrude outward from the side rib located radially outside the cutout portion.

[0055] Each of the two side ribs 19a and 19b arranged on the inlet side is aligned with the central axis O of the outer cylinder portion 14a arranged on the inlet side. 14a The two side ribs 19a, 19b extend in a direction approaching the center of the circumferential wall. Therefore, the two side ribs 19a, 19b are arranged non-parallel to each other. The side rib 19a arranged on the radially outer side is inclined radially inward as it moves circumferentially inward. In contrast, the side rib 19b arranged on the radially inner side is inclined radially outward as it moves circumferentially inward. The inclination angle between the two side ribs 19a, 19b is approximately 10° to 60°, and more preferably approximately 20° to 50°.

[0056] The axially outer surface of each of the side ribs 19a, 19b is inclined in a substantially linear manner so that the outer surface is closer to the circumferential outside and the inner surface is closer to the axial inside.

[0057] Of the two side ribs 20a, 20b arranged on the outlet side, the circumferentially outer end of the side rib 20a arranged radially outside the cutout portion 18b is connected to the circumferentially inner portion of the outlet-side coupling portion 8. The circumferentially inner end of the side rib 20a is connected to the circumferentially outer end of the radially outer portion of the center rib 21. In contrast, of the two side ribs 20a, 20b, the circumferentially outer end of the side rib 20b arranged radially inside the cutout portion 18b is located circumferentially outer than the circumferentially outer end of the side rib 20a, and is connected to the circumferentially outer end of the outlet-side coupling portion 8. The circumferentially inner end of the side rib 20b is connected to the circumferentially outer end of the radially inner portion of the center rib 21 at approximately the same circumferential position (position X2) as the circumferentially inner end of the side rib 20a. When carrying out the present invention, the circumferentially inner portions of the side ribs may be connected to the circumferentially outer ends of the center ribs and directly connected to the cylindrical portion of the outer cylinder portion on the outlet side.

[0058] The two side ribs 20a, 20b have slightly different radial thicknesses. Specifically, at the same circumferential position, the radial thickness of the side rib 20a located radially outside the cutout portion 18b is slightly greater than the radial thickness of the side rib 20b located radially inside the cutout portion 18b. Furthermore, as shown in FIG. 1 , when the caliper 2 is viewed from the radial outside, a portion of the side rib 20b located radially inside the cutout portion 18b slightly protrudes outward from the side rib 20a located radially outside the cutout portion 18b. When implementing the present invention, a majority of the side rib located radially inside the cutout portion may protrude outward from the side rib located radially outside the cutout portion.

[0059] The two side ribs 20a and 20b arranged on the outlet side are aligned with the central axis O of the outer cylinder portion 14c arranged on the outlet side. 14cThe two side ribs 20a, 20b are arranged non-parallel to each other. The side rib 20a arranged on the radially outer side is inclined radially inward as it moves circumferentially inward. In contrast, the side rib 20b arranged on the radially inner side is inclined radially outward as it moves circumferentially inward. The inclination angle between the two side ribs 20a, 20b is the same as the inclination angle between the two side ribs 19a, 19b arranged on the inlet side.

[0060] The axially outer surface of each of the side ribs 20a, 20b is inclined in a substantially linear manner in a direction that is closer to the axially inner side as it is closer to the circumferentially outer side.

[0061] In this example, the outer reinforcing rib 17 has a symmetrical shape in the axial direction, so that the two side ribs 19a, 19b arranged on the inlet side and the two side ribs 20a, 20b arranged on the outlet side have a symmetrical shape in the axial direction.

[0062] The center rib 21 is provided on the circumferentially inner side (middle part) of the outer-side reinforcing rib 17. The center rib 21 extends in the circumferential direction and covers the radially middle parts of the bottom parts 16a, 16b, 16c of the three outer cylinder parts 14a, 14b, 14c from the axially outer side, crossing the circumferential direction. Therefore, the radially outer and radially inner parts of the bottom parts 16a, 16b, 16c of the outer cylinder parts 14a, 14b, 14c are not covered by the center rib 21 and protrude radially from the center rib 21.

[0063] The radial width of the center rib 21 is larger than the radial width of each of the side ribs 19a, 19b, 20a, and 20b, and smaller than the diameter of the bottoms 16a, 16b, and 16c of the outer cylinder portions 14a, 14b, and 14c. Specifically, the radial width of the center rib 21 at both circumferential outer portions, where the radial width is greatest, is about two to three times the radial width of each of the side ribs 19a, 19b, 20a, and 20b, and at the circumferential central portion, where the radial width is smallest, is about 1.2 to 1.5 times the radial width of each of the side ribs 19a, 19b, 20a, and 20b.

[0064] Both circumferentially outer ends of the center rib 21 are circumferentially connected to the circumferentially inner ends of the side ribs 19a, 19b arranged on the inlet side and the circumferentially inner ends of the side ribs 20a, 20b arranged on the outlet side. The boundary position between the circumferentially outer end of the center rib 21 on the inlet side and the circumferentially inner ends of the side ribs 19a, 19b arranged on the inlet side is the position indicated by X1 in Fig. 2, and the boundary position between the circumferentially outer end of the center rib 21 on the outlet side and the circumferentially inner ends of the side ribs 20a, 20b arranged on the outlet side is the position indicated by X2 in Fig. 2.

[0065] The center rib 21 has a flat design surface 22 at the circumferential center of its axially outer surface that can be used to display letters, graphics, etc., and curved surface portions 23 on both circumferential outer sides of its axially outer surface. The design surface 22 of the center rib 21 and the axially outer surfaces of each of the four side ribs 19a, 19b, 20a, and 20b are smoothly connected without any steps via the curved surface portions 23. When practicing the present invention, the design surface of the center rib can also be directly and smoothly connected to the axially outer surfaces of the side ribs without any steps.

[0066] The radially outer surface of the center rib 21 is a partial cylindrical surface that is slightly curved in an arc shape so that the radially inner side is convex, and the radially inner surface of the center rib 21 is a partial cylindrical surface that is curved in an arc shape so that the radially outer side is convex. In this example, the radially outer surface of the center rib 21 and the radially outer surfaces of the pair of side ribs 19 a, 20 a located on the radially outer side are smoothly connected in the circumferential direction. Furthermore, the radially inner surface of the center rib 21 and the radially inner surfaces of the pair of side ribs 19 b, 20 b located on the radially inner side are smoothly connected in the circumferential direction.

[0067] The outer body 6 supports the pads 3 arranged axially outward of the rotor 4 so as to be movable in the axial direction. For this purpose, the outer body 6 has outer-side protrusions 29 that protrude in the axial direction on both circumferential outer sides of the axially inner surface.

[0068] <<Inlet and outlet connection sections>> The inlet-side coupling portion 7 and the outlet-side coupling portion 8 are disposed radially outward from the outer circumferential edge of the rotor 4. The inlet-side coupling portion 7 axially couples the circumferentially outer end of the inlet-side of the inner body 5 to the circumferentially outer end of the inlet-side of the outer body 6. The outlet-side coupling portion 8 axially couples the circumferentially outer end of the outlet-side of the inner body 5 to the circumferentially outer end of the outlet-side of the outer body 6. The inlet-side coupling portion 7 and the outlet-side coupling portion 8 have a partially cylindrical shape curved in an arc and cover the rotor 4 from the radially outer side. The inner circumferential surfaces of the inlet-side coupling portion 7 and the outlet-side coupling portion 8 each have a rotor pass portion 24, which is a recess for allowing the outer circumferential edge of the rotor 4 to enter. The area surrounded on all four sides by the inner and outer bodies 5, 6 and the inlet-side and outlet-side coupling portions 7, 8 forms an opening 25 that penetrates radially and has a generally rectangular shape in plan view.

[0069] 《Communication path》 8, a communication passage 26 for passing brake oil is provided inside the caliper 2. Brake oil is sent from the master cylinder to the communication passage 26. The communication passage 26 is made up of a total of eight through holes, from a first through hole 27a to an eighth through hole 27h.

[0070] The first through hole 27a to the third through hole 27c are each provided inside the inner body 5. The first through hole 27a extends linearly in the circumferential direction so as to cross each of the inner cylinder portions 9a, 9b, and 9c. The second through hole 27b is disposed closer to the rotation-inlet side than the rotation-inlet side inner cylinder portion 9a and is connected to the first through hole 27a. The second through hole 27b extends obliquely toward the rotation-inlet side as it moves axially outward. The third through hole 27c is mostly disposed closer to the rotation-outlet side than the rotation-outlet side inner cylinder portion 9c and is connected to the first through hole 27a. The third through hole 27c extends obliquely toward the rotation-outlet side as it moves axially outward.

[0071] The fourth through hole 27d is provided inside the rotation-inlet side connecting portion 7 and extends in the axial direction. The axially inner portion of the fourth through hole 27d communicates with the second through hole 27b. The fifth through hole 27e is provided inside the rotation-outlet side connecting portion 8 and extends in the axial direction. The axially inner portion of the fifth through hole 27e communicates with the third through hole 27c.

[0072] The sixth through hole 27f to the eighth through hole 27h are provided inside the outer body 6. The sixth through hole 27f extends linearly in the circumferential direction so as to cross each of the outer cylinder portions 14a, 14b, and 14c. The seventh through hole 27g is disposed closer to the rotation-inlet side than the rotation-inlet outer cylinder portion 14a and communicates with each of the fourth through hole 27d and the sixth through hole 27f. The seventh through hole 27g extends obliquely toward the rotation-inlet side as it moves axially inward. The eighth through hole 27h is mostly disposed closer to the rotation-outlet side than the rotation-outlet outer cylinder portion 14c and communicates with each of the fifth through hole 27e and the sixth through hole 27f. The eighth through hole 27h extends obliquely toward the rotation-outlet side as it moves axially inward.

[0073] In this example, of the pair of side ribs 19a, 19b arranged on the inlet side, a seventh through hole 27g constituting the communicating passage 26 is formed inside the side rib 19a arranged on the radially outer side. The seventh through hole 27g opens on the axially outer surface of the side rib 19a. Furthermore, of the pair of side ribs 20a, 20b arranged on the outlet side, an eighth through hole 27h constituting the communicating passage 26 is formed inside the side rib 20a arranged on the radially outer side. The eighth through hole 27h opens on the axially outer surface of the side rib 20a.

[0074] <pad> As shown in FIG. 1, each of the pair of pads 3 is made up of a lining (friction material) 30 and a metal backing plate (pressure plate) 31 that supports the back surface of the lining 30.

[0075] In this example, the inner pad 3 (inner pad) disposed axially inside the rotor 4 is disposed between a pair of inner protrusions 28, and both circumferentially outer ends of a back plate 31 constituting the inner pad 3 are engaged with the pair of inner protrusions 28 so as to be movable in the axial direction. This supports the inner pad 3 axially movable relative to the inner body 5.

[0076] Additionally, the outer pad 3 (outer pad) disposed axially outside the rotor 4 is disposed between a pair of outer protrusions 29, and both circumferentially outer ends of a back plate 31 constituting the outer pad 3 are engaged with the pair of outer protrusions 29 so as to be movable in the axial direction. This supports the outer pad 3 axially movable relative to the outer body 6.

[0077] Although not shown, pad clips may be interposed between both circumferentially outer surfaces of the back plates 31 constituting each of the pair of pads 3 and the circumferentially inner surfaces of the inner-side protruding portion 28 and the outer-side protruding portion 29. When implementing the present invention, the support structure for the pair of pads 3 relative to the inner and outer bodies 5, 6 is not limited to the structure described above, and various conventionally known structures may be employed.

[0078] In the opposed-piston disc brake device 1 of this embodiment as described above, during braking, brake oil is sent from the master cylinder to each of the inner cylinder portions 9a, 9b, 9c and the outer cylinder portions 14a, 14b, 14c through the communication passage 26. This pushes the inner pistons fitted in the inner cylinder portions 9a, 9b, 9c in the axial direction, pressing the inner pads 3 supported by the inner body 5 against the axially inner surface of the rotor 4. Similarly, the outer pistons fitted in the outer cylinder portions 14a, 14b, 14c in the axial direction, pressing the outer pads 3 supported by the outer body 6 against the axially outer surface of the rotor 4. As a result, the rotor 4 is tightly clamped from both axial sides by the pair of pads 3, thereby braking the vehicle.

[0079] In particular, in the case of this example, the caliper 2 constituting the opposed piston type disc brake device 1 can achieve both high rigidity and light weight at the same time.

[0080] [Reasons for improving rigidity] In the caliper 2 of this example, the band-shaped outer reinforcing rib 17 (center rib 21) covers the bottom portions 16a, 16b, and 16c of the outer cylinder portions 14a, 14b, and 14c from the axially outer side. This improves the axial rigidity of the bottom portions 16a, 16b, and 16c of the outer cylinder portions 14a, 14b, and 14c of the outer body 6. This prevents the bottom portions 16a, 16b, and 16c of the outer cylinder portions 14a, 14b, and 14c from elastically deforming axially outward during braking, thereby preventing the inner body 5 and the outer body 6 from elastically deforming in directions away from each other in the axial direction. As a result, the opposed-piston disc brake device 1 of this example can obtain a desired braking force. Furthermore, the outer-side reinforcing rib 17 extends in the circumferential direction, and both circumferential ends are connected to the inlet-side connecting portion 7 and the outlet-side connecting portion 8, thereby improving the circumferential rigidity of the outer body 6. This makes it possible to suppress elastic deformation of the outer body 6 relative to the inner body 5 in the circumferential direction (the direction of rotation of the rotor 4) during braking, thereby suppressing vibration and noise.

[0081] In this example, a pair of side ribs 19a, 19b arranged on the outer circumferential side of the outer reinforcing rib 17 are aligned along the central axis O of the outer cylinder portion 14a on the inlet side. 14a The pair of side ribs 19a, 19b are arranged non-parallel to each other. In addition, the pair of side ribs 20a, 20b arranged on the circumferential outer side of the outer reinforcing rib 17 on the rotation side are each aligned with the central axis O of the outer cylinder portion 14c on the rotation side. 14c The pair of side ribs 20a, 20b are arranged non-parallel to each other, which improves the torsional rigidity of the outer body 6 and also prevents the bottoms 16a, 16b, 16c of the outer cylinder portions 14a, 14b, 14c from elastically deforming axially outward.

[0082] In this example, of the pair of side ribs 19a, 19b arranged on the inlet side, the radially outer side rib 19a has a radial thickness slightly greater than that of the radially inner side rib 19b. Also, of the pair of side ribs 20a, 20b arranged on the outlet side, the radially outer side rib 20a has a radial thickness slightly greater than that of the radially inner side rib 20b. This increases the radial compressive stress of the radially outer side ribs 19a, 20a, effectively preventing the outer body 6 from elastically deforming in the axial direction away from the inner body 5 during braking.

[0083] Furthermore, when the caliper 2 is viewed from the radial outside, of the pair of side ribs 19a, 19b arranged on the rotation inlet side, the side rib 19b arranged on the radially inner side protrudes outward from the side rib 19a arranged on the radially outer side. Similarly, of the pair of side ribs 20a, 20b arranged on the rotation outlet side, the side rib 20b arranged on the radially inner side protrudes outward from the side rib 20a arranged on the radially outer side. This increases the axial and / or circumferential tensile stress of the side ribs 19b, 20b arranged on the radially inner side, effectively suppressing elastic deformation of the outer body 6 in the axial direction away from the inner body 5 during braking.

[0084] [Reasons for weight reduction] The caliper 2 of this example has cutout portions 18a, 18b on both circumferentially outer sides of the outer reinforcing rib 17. In other words, the cutout portions 18a, 18b are provided without providing outer reinforcing ribs in areas that do not sufficiently contribute to improving rigidity. This makes it possible to reduce the weight of the caliper 2 while ensuring the rigidity of the caliper 2. In particular, in this example, the cutout portions 18a, 18b are provided in areas that are offset circumferentially outward from the bottoms 16a, 16c of the outer cylinder portions 14a, 14c, respectively, so that it is possible to reduce the weight while sufficiently reinforcing the bottoms 16a, 16b, 16c.

[0085] Furthermore, the radial width of the center rib 21 constituting the outer reinforcing rib 17 is made smaller than the diameter of the bottoms 16a, 16b, 16c of the outer cylinder portions 14a, 14b, 14c, respectively, and the center rib 21 covers only the radial middle portions of the bottoms 16a, 16b, 16c of the outer cylinder portions 14a, 14b, 14c. Therefore, the provision of the outer reinforcing rib 17 can prevent the weight of the caliper 2 from increasing unnecessarily.

[0086] Furthermore, in this example, a seventh through hole 27g constituting the communicating passage 26 is formed inside the side rib 19a located on the inlet side and on the radially outer side, and an eighth through hole 27h constituting the communicating passage 26 is formed inside the side rib 20a located on the outlet side and on the radially outer side. This eliminates the need for external piping for passing brake oil, allowing for a reduction in the number of parts and weight.

[0087] As a result, the caliper 2 of this embodiment can achieve both high rigidity and light weight at the same time.

[0088] In this example, the design surface 22 of the center rib 21 and the axially outer side surfaces of each of the four side ribs 19a, 19b, 20a, and 20b are smoothly connected without any steps via the curved surface portions 23. This improves the design of the caliper 2 from the axially outer side. It also helps prevent stress from concentrating at the connection portions between the center rib 21 and the side ribs 19a, 19b, 20a, and 20b.

[0089] [Second example of embodiment] A second example of the embodiment will be described with reference to FIG.

[0090] In this example, only the structure of both outer circumferential portions of the outer reinforcing rib 17a is changed from the structure of the first example of the embodiment.

[0091] Specifically, in this example, two bottomed recesses 18c, 18d are provided radially side by side in the radial middle portion of the circumferential outer portion on the inlet side of the outer reinforcing rib 17a, and two bottomed recesses 18e, 18f are provided radially side by side in the radial middle portion of the circumferential outer portion on the outlet side of the outer reinforcing rib 17a.

[0092] Each of the four cutout portions 18c to 18f has a circumferentially elongated shape with a circumferential width greater than its radial width. Specifically, each of the four cutout portions 18c to 18f has a substantially triangular shape when viewed in the axial direction. The radial width of each of the cutout portions 18c to 18f increases toward the circumferential outside.

[0093] Of the two cutout portions 18c, 18d arranged on the inlet side, the cutout portion 18d arranged on the radially inner side has a longer circumferential length than the cutout portion 18c arranged on the radially outer side. The circumferential outer end of the cutout portion 18d arranged on the radially inner side is located further outward in the circumferential direction than the circumferential outer end of the cutout portion 18c arranged on the radially outer side. Furthermore, of the two cutout portions 18e, 18f arranged on the outlet side, the cutout portion 18f arranged on the radially inner side has a longer circumferential length than the cutout portion 18e arranged on the radially outer side. The circumferential outer end of the cutout portion 18f arranged on the radially inner side is located further outward in the circumferential direction than the circumferential outer end of the cutout portion 18e arranged on the radially outer side.

[0094] The outer-side reinforcement rib 17a has three side ribs 19c, 19d, and 19e that sandwich each of the two cutout portions 18c and 18d located on the inlet side from both radial sides. Specifically, side ribs 19c and 19d are provided on both radial sides of the radially outer cutout portion 18c, and side ribs 19d and 19e are provided on both radial sides of the radially inner cutout portion 18d. The outer-side reinforcement rib 17a also has three side ribs 20c, 20d, and 20e that sandwich each of the two cutout portions 18e and 18f located on the outlet side from both radial sides. Specifically, side ribs 20c and 20d are provided on both radial sides of the radially outer cutout portion 18e, and side ribs 20d and 20e are provided on both radial sides of the radially inner cutout portion 18f. Therefore, the outer reinforcing rib 17a of this example has a total of six side ribs 19c, 19d, 19e, 20c, 20d, and 20e.

[0095] The three side ribs 19c, 19d, and 19e located on the inlet side are arranged non-parallel to one another. The side rib 19c located on the radially outer side is inclined radially inward as it moves circumferentially inward. In contrast, the side rib 19d located in the radially middle portion and the side rib 19e located on the radially inner side are inclined radially outward as they move circumferentially inward.

[0096] The circumferentially outer end of side rib 19c, which is arranged radially outward, is connected to the circumferentially inner part of the rotation-side connecting part 7. The circumferentially outer end of side rib 19d, which is arranged in the radially intermediate part, is connected to the circumferential intermediate part of the rotation-side connecting part 7. The circumferentially outer end of side rib 19e, which is arranged radially inward, is connected to the circumferentially outer end of the rotation-side connecting part 7. The circumferentially inner end of each of the three side ribs 19c, 19d, and 19e arranged on the rotation side is connected to the circumferentially outer end of the center rib 21 on the rotation side.

[0097] The three side ribs 20c, 20d, and 20e arranged on the outlet side are arranged non-parallel to one another. The side rib 20c arranged on the radially outer side is inclined radially inward as it moves circumferentially inward. In contrast, the side rib 20d arranged in the radially middle portion and the side rib 20e arranged radially inward are inclined radially outward as it moves circumferentially inward.

[0098] The circumferentially outer end of side rib 20c, which is arranged radially outward, is connected to the circumferentially inner part of outlet-side connecting portion 8. The circumferentially outer end of side rib 20d, which is arranged in the radially intermediate part, is connected to the circumferential intermediate part of outlet-side connecting portion 8. The circumferentially outer end of side rib 19e, which is arranged radially inward, is connected to the circumferentially outer end of outlet-side connecting portion 8. The circumferentially inner end of each of the three side ribs 20c, 20d, and 20e arranged on the outlet side is connected to the circumferentially outer end of center rib 21 on the outlet side.

[0099] In the present example as described above, the number of undercut portions can be increased by two compared to the structure of the first example of the embodiment, and therefore the weight of the caliper 2 can be further reduced. The other configurations and effects are the same as those of the first embodiment.

[0100] [Third example of embodiment] A third example of the embodiment will be described with reference to FIG.

[0101] In this example, only the structure of both outer circumferential portions of the outer reinforcing rib 17b is changed from the structure of the first example of the embodiment.

[0102] Specifically, the outer-side reinforcing rib 17b of this example further includes a radial rib 32a that radially connects the circumferential middle portions of the two side ribs 19a, 19b arranged on the inlet side. The radial rib 32a circumferentially divides the cutout portion 18a (see FIG. 2 ) provided between the two side ribs 19a, 19b into two. In other words, the outer-side reinforcing rib 17b has two cutout portions 18g, 18h arranged side by side in the circumferential direction between the two side ribs 19a, 19b. Of the two cutout portions 18g, 18h, the cutout portion 18g located on the inner side in the circumferential direction is open only axially outward, whereas the cutout portion 18h located on the outer side in the circumferential direction is open both axially and circumferentially outward.

[0103] The outer-side reinforcing rib 17b further includes a radial rib 32b that radially connects the circumferential middle portions of the two side ribs 20a, 20b arranged on the outlet side. The radial rib 32b circumferentially divides a cutout portion 18b (see FIG. 2) provided between the two side ribs 20a, 20b into two. In other words, the outer-side reinforcing rib 17b has two cutout portions 18i, 18j arranged side by side in the circumferential direction between the two side ribs 20a, 20b. Of the two cutout portions 18i, 18j, the cutout portion 18i located on the inner side in the circumferential direction is open only axially outward, whereas the cutout portion 18j located on the outer side in the circumferential direction is open both axially and circumferentially outward.

[0104] In the present example as described above, the two side ribs 19a, 19b arranged on the rotation inlet side are radially connected by the radial rib 32a, and the two side ribs 20a, 20b arranged on the rotation outlet side are radially connected by the radial rib 32b, which further improves the rigidity of the outer body 6. This effectively prevents the outer body 6 from elastically deforming in the axial direction away from the inner body 5 during braking. The other configurations and effects are the same as those of the first embodiment.

[0105] [Fourth Example of Implementation Form] A fourth example of the embodiment will be described with reference to FIGS.

[0106] In this example, only the structure of the cutout portions 33a, 33b provided on both outer sides in the circumferential direction of the outer side reinforcing rib 17c is changed from the structure of the first example of the embodiment.

[0107] Specifically, in this example, a bottomless cutout portion 33a which is a through hole is provided in the radially middle portion of the circumferential outer portion on the inlet side of the outer reinforcing rib 17c, and a bottomless cutout portion 33b which is a through hole is provided in the radially middle portion of the circumferential outer portion on the outlet side of the outer reinforcing rib 17c.

[0108] Each of the cutouts 33a, 33b is a triangular hole having a substantially right-angled triangular shape when viewed in the axial direction, and is deeper in the axial direction and shorter in the circumferential direction than the bottomed cutouts 18a, 18b of the first embodiment (see FIG. 2).

[0109] In the present embodiment described above, the cutouts 33a, 33b provided on both circumferentially outer sides of the outer reinforcing rib 17c are each a bottomless through-hole. Therefore, when the weight of the caliper 2 is the same as that of the structure of the first embodiment, the circumferential dimensions of the cutouts 33a, 33b can be made shorter than that of the structure of the first embodiment. This reduces irregularities on the axially outer surface of the outer body 6, improving design freedom. It also improves the heat dissipation effect of the caliper 2. The other configurations and effects are the same as those of the first embodiment.

[0110] Although the embodiments of the present invention have been described above, the present invention is not limited to these and can be modified as appropriate within the scope of the technical concept of the invention. Furthermore, the structures of the examples of the embodiments can be combined as appropriate as long as no contradiction occurs.

[0111] In each of the embodiments, a structure in which cutout portions are provided on both circumferential outer sides of the outer reinforcing rib has been described, but when implementing the present invention, the arrangement and number of cutout portions are not limited to the structures shown in each of the embodiments. For example, when implementing the present invention, cutout portions may be provided only on the circumferential outer side of the inlet side or only on the circumferential outer side of the outlet side. Furthermore, when multiple cutout portions are provided, bottomed cutout portions and bottomless cutout portions may be combined. Furthermore, the number and shape of the cutout portions provided on the circumferential outer side of the inlet side may be different from the number and shape of the cutout portions provided on the circumferential outer side of the outlet side.

[0112] When implementing the present invention, the caliper for an opposed-piston disc brake may have a monocoque structure (integrated structure) integrally constructed from a material such as an aluminum alloy, or may have a structure in which an inner body and an outer body are connected by bolts. Furthermore, the number of inner cylinder portions and outer cylinder portions is not limited to three as described in the embodiment, and may be one, two, or four or more. [Explanation of symbols]

[0113] 1 Opposed piston type disc brake device 2 calipers 3 Pad 4 rotors 5 Inner Body 6 Outer Body 7 Entry side connection part 8 Output side connection part 9a, 9b, 9c Inner cylinder section 10a, 10b Mounting holes 11a, 11b, 11c cylinder part 12a, 12b, 12c bottom 13 Inner reinforcing rib 14a, 14b, 14c Outer cylinder part 15a, 15b, 15c cylinder part 16a, 16b, 16c bottom 17, 17a-17c Outer reinforcing rib 18a~18j Missing part 19a~19e Side Rib 20a~20e Side rib 21 Center Rib 22 Design surface 23 Curved part 24 Rotor path section 25 Opening 26 Communication path 27a~27h 1st through hole ~ 8th through hole 28 Inner side protrusion 29 Outer overhang 30 Lining 31 Back plate 32a, 32b Radial ribs 33a, 33b missing part

Claims

1. an inner body having an inner cylinder portion and disposed axially inside the rotor; an outer body having an outer cylinder portion and disposed axially outward of the rotor; a rotation-inlet-side connecting portion and a rotation-outlet-side connecting portion that are arranged radially outward of an outer peripheral edge of the rotor and axially connect both circumferentially outer ends of the inner body and both circumferentially outer ends of the outer body, the outer body has both circumferentially outer ends connected to the inlet-side connecting portion and the outlet-side connecting portion, and is provided with a band-shaped reinforcing rib that covers a bottom portion of the outer cylinder portion from the axially outer side so as to cross the circumferential direction, The reinforcing rib has a recessed portion with or without a bottom that is recessed in the axial direction on at least one of both circumferential outer portions. Opposed piston type disc brake caliper.

2. The recessed portion has a shape that is elongated in the circumferential direction, The reinforcing rib has side ribs extending in the circumferential direction on both radial sides of the recessed portion, The side ribs are provided in a total of two or more.

2. A caliper for an opposed piston type disc brake according to claim 1.

3. 3. The caliper for an opposed-piston type disc brake according to claim 2, wherein each of the side ribs extends in a direction approaching the central axis of the outer cylinder portion as it moves circumferentially inward.

4. The recessed portion is provided in a radially intermediate portion of the reinforcing rib, the side ribs arranged radially outward of the recessed portions are inclined radially inward as they move inward in the circumferential direction, The side rib disposed radially inward of the recessed portion is inclined in a direction toward the radially outward side as it moves toward the circumferentially inward.

4. A caliper for an opposed piston type disc brake according to claim 3.

5. 5. The caliper for an opposed-piston type disc brake according to claim 4, wherein the side rib arranged radially inside the recessed portion is connected to the circumferentially outer end of the inlet-side connecting portion or the outlet-side connecting portion.

6. 3. The caliper for an opposed-piston disc brake according to claim 2, wherein a radial thickness of the side rib disposed radially outside the recessed portion is greater than a radial thickness of the side rib disposed radially inside the recessed portion.

7. 3. The caliper for an opposed-piston type disc brake according to claim 2, wherein, when viewed from the radial outside, the side rib arranged radially inside the cutout portion protrudes outward from the side rib arranged radially outside the cutout portion.

8. The reinforcing rib has, at a circumferentially inner portion, a flat design surface formed by an axially outer surface of the reinforcing rib, The design surface and the axially outer surface of the side rib are smoothly connected without any steps.

3. A caliper for an opposed piston type disc brake according to claim 2.

9. 3. The caliper for an opposed-piston disc brake according to claim 2, wherein the axially outer side surfaces of the side ribs are inclined in a direction that approaches the axially inner side as they extend outward in the circumferential direction.

10. 3. The caliper for an opposed-piston disc brake according to claim 2, wherein at least one of said side ribs has a communication passage therein for passing brake oil.

11. The recessed portion is provided at a radially intermediate portion of each of both circumferentially outer portions of the reinforcing rib, Each of the cutout portions has a generally triangular shape when viewed in the axial direction, and a radial width thereof increases toward the outer side in the circumferential direction, A portion of the reinforcing rib excluding the undercut portion has a substantially X-shape when viewed in the axial direction.

2. A caliper for an opposed piston type disc brake according to claim 1.

12. 12. The caliper for an opposed-piston disc brake according to claim 11, wherein an axial thickness of the reinforcing rib excluding the undercut portion is greater in a portion of the reinforcing rib that is circumferentially outwardly spaced from the outer cylinder portion than in a portion that covers the bottom of the outer cylinder portion.

13. 2. The caliper for an opposed-piston type disc brake according to claim 1, wherein the recessed portion has a bottom.

14. 2. The caliper for an opposed-piston type disc brake according to claim 1, wherein the recessed portion has no bottom.

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