Opposed-piston disc brake caliper

Abstract

The present application realizes a caliper for an opposed-piston disc brake that ensures rigidity and lightness. In the present application, the turn-in side side bridge (7) and the turn-out side side bridge (8) that link the end portion of the circumferential outer side of the inner body (5) constituting the caliper (2) and the end portion of the circumferential outer side of the outer body (6) in the axial direction are provided with: a recess (28) that is elongated in the axial direction and is open in the outer surface; and a first beam portion (29) and a second beam portion (30) that are arranged in a manner of sandwiching the recess (28) from both sides and the end portion of the respective axial inner side is connected to the mounting boss portion (11a, 11b) provided in the inner body (5).

Description

TECHNICAL FIELD

[0001] The present application relates to a caliper that constitutes an opposed-piston type disc brake device. BACKGROUND

[0002] In order to perform braking of an automobile, a disc brake device is widely used. In braking using a disc brake device, a pair of pads disposed on both axial sides of a rotor that rotates together with a wheel are pressed against both axial side surfaces of the rotor by pistons. As such disc brake devices, various structures have been known in the past, but since an opposed-piston type disc brake device having pistons on both axial sides of a rotor can obtain stable braking force, the number of uses has increased in recent years.

[0003] The opposed-piston type disc brake device is provided with, for example, a caliper disposed so as to cover a rotor that rotates together with a wheel from the radially outer side, and fixed to a vehicle body, and a pair of pads supported so as to be axially movable with respect to the caliper, and disposed on both axial sides of the rotor, as described in Japanese Patent Application Publication No. 2010-78055 (Patent Literature 1).

[0004] The caliper has an inner body disposed on the inner axial side of the rotor, an outer body disposed on the outer axial side of the rotor, and a pair of side bridges disposed so as to cover the rotor from the radially outer side, and linking the end portions on both circumferential outer sides of the inner body and the end portions on both circumferential outer sides of the outer body.

[0005] The inner body has an inner cylinder portion opened on the outer axial side opposite the rotor, and an inner piston is fitted in the inner cylinder portion. In addition, the inner body has a pair of mounting boss portions for fixing the caliper to the vehicle body on both circumferential outer sides of the inner cylinder. The outer body has an outer cylinder portion opened on the inner axial side opposite the rotor, and an outer piston is fitted in the outer cylinder portion.

[0006] At the time of braking, brake oil is supplied to the inner cylinder portion and the outer cylinder portion from a master cylinder, respectively. As a result, the inner piston fitted in the inner cylinder portion is pushed out in the axial direction, and the pad supported by the inner body is pressed against the inner axial side surface of the rotor. Similarly, the outer piston fitted in the outer cylinder portion is pushed out in the axial direction, and the pad supported by the outer body is pressed against the outer axial side surface of the rotor. As a result, the rotor is strongly sandwiched from both axial sides by the pair of pads, and braking of the vehicle is performed.

[0007] PRIOR ART DOCUMENTS

[0008] PATENT LITERATURE

[0009] Patent Literature 1: Japanese Patent Application Publication No. 2010-78055 SUMMARY

[0010] PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] At the time of braking, a force in a direction in which the inner body and the outer body are separated from each other in the axial direction is applied to the inner body and the outer body as a reaction force of pressing the pair of pads toward both sides of the rotor in the axial direction by the inner and outer pistons. Therefore, if the rigidity of the side bridge that links the inner body and the outer body in the axial direction is not sufficient, the inner body and the outer body can be elastically deformed in a direction in which they are separated from each other, and the desired braking force cannot be obtained.

[0012] On the other hand, the disc brake device is provided in a position closer to the road surface than a spring that constitutes a suspension device in a vehicle, and thus becomes a so-called spring-down load. Therefore, in order to improve the fuel consumption performance and the running performance of the vehicle, it is required to achieve weight reduction.

[0013] The present application has been achieved in order to solve the above-described problems, and aims to provide a caliper for a opposed-piston type disc brake that can achieve both rigidity and weight reduction.

[0014] Technical means for solving the problems

[0015] The caliper for the opposed-piston type disc brake according to one aspect of the present application includes an inner body, an outer body, and a pair of side bridges.

[0016] The inner body is disposed on the inner side in the axial direction of the rotor, and has at least one or more inner cylinder portions, and a pair of mounting boss portions disposed on both sides in the circumferential direction of the at least one or more inner cylinder portions, and each formed with a bolt insertion hole that penetrates in the radial direction.

[0017] The outer body is disposed on the outer side in the axial direction of the rotor, and has at least one or more outer cylinder portions.

[0018] The pair of side bridges are disposed so as to cover the rotor from the outer side in the radial direction, and link the end portions on both sides in the circumferential direction of the inner body and the end portions on both sides in the circumferential direction of the outer body in the axial direction.

[0019] In the caliper for the opposed-piston type disc brake according to one aspect of the present application, at least one of the pair of side bridges has a recess portion that is elongated in the axial direction and opens on the outer surface of the side bridge, and a first beam portion and a second beam portion disposed so as to sandwich the recess portion from both sides, and the end portions on the inner side in the axial direction of the first beam portion and the second beam portion are connected to the mounting boss portion directly or via a portion of the side bridge located in the vicinity of the mounting boss portion.

[0020] In the caliper for the opposed-piston type disc brake according to one aspect of the present application, the end portion on the outer side in the axial direction of the recess portion can have an axial bottom portion.

[0021] In the caliper for a disc brake of the opposed-piston type according to one aspect of the present application, the recess can be open to the outer circumferential surface and / or the circumferential outer side surface of the side bridge.

[0022] In the caliper for a disc brake of the opposed-piston type according to one aspect of the present application, the recess can be open to the axial inner side surface of the side bridge.

[0023] In the caliper for a disc brake of the opposed-piston type according to one aspect of the present application, the ridge line of the first beam portion can be connected to the end portion on the radially inner side of the mounting boss portion via the ridge line of the portion of the side bridge located in the vicinity of the mounting boss portion.

[0024] In the caliper for a disc brake of the opposed-piston type according to one aspect of the present application, the second beam portion can be directly connected to the end portion on the radially outer side of the mounting boss portion.

[0025] In the caliper for a disc brake of the opposed-piston type according to one aspect of the present application, the first beam portion and the second beam portion can be disposed so as to sandwich the recess in the circumferential direction.

[0026] In the caliper for a disc brake of the opposed-piston type according to one aspect of the present application, at least either one of the first beam portion and the second beam portion can have a cross-sectional area that becomes larger toward the axial outer side.

[0027] In this case, the circumferential direction width of the second beam portion can become larger toward the axial outer side. Additionally or alternatively, the radial width of the first beam portion can become larger toward the axial outer side.

[0028] In the caliper for a disc brake of the opposed-piston type according to one aspect of the present application, the side bridge can have a protruding portion that protrudes in a direction in which the opening area of the recess is reduced, at the opening portion of the recess.

[0029] In this case, the protruding portion can be provided at the axial outer side portion of the opening portion of the recess. Additionally or alternatively, the protruding portion can be provided at the circumferential inner side portion and / or the circumferential outer side portion of the opening portion of the recess.

[0030] In the caliper for a disc brake of the opposed-piston type according to one aspect of the present application, the central axis of the recess can be inclined toward the direction in which the circumferential inner side is inclined more toward the axial outer side, with respect to the central axis of the inner cylinder portion.

[0031] Effects of Invention

[0032] According to the present application, it is possible to realize a caliper for a disc brake of the opposed-piston type that ensures rigidity and light weight. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a plan view of the opposed-piston type disc brake device related to the first example of the embodiment, viewed from the radially outer side.

[0034] Figure 2 is a view of the opposed-piston type disc brake device related to the first example of the embodiment, viewed from the axially inner side.

[0035] Figure 3 is a view of the opposed-piston type disc brake device related to the first example of the embodiment, viewed from the axially outer side.

[0036] Figure 4 is a side view, viewed from the left side of Figure 2

[0037] Figure 5 is a side view, viewed from the right side of Figure 2

[0038] Figure 6 is a bottom view of the opposed-piston type disc brake device related to the first example of the embodiment, viewed from the radially inner side.

[0039] Figure 7 is an A-A line sectional view of Figure 1

[0040] Figure 8 is a B-B line sectional view of Figure 1

[0041] Figure 9 is a perspective view of the opposed-piston type disc brake device related to the first example of the embodiment, viewed from the axially inner side and the radially outer side.

[0042] Figure 10 is a perspective view of the opposed-piston type disc brake device related to the first example of the embodiment, viewed from the axially outer side and the radially outer side.

[0043] Figure 11 is a partial enlarged view of Figure 9

[0044] SYMBOL EXPLANATION

[0045] 1 opposed-piston type disc brake device

[0046] 2 caliper

[0047] 3 pad

[0048] 4 rotor

[0049] 5 inner body

[0050] 6 outer body​​​​​

[0051] 7 inboard side bridge

[0052] 8 outboard side bridge

[0053] 9 center bridge

[0054] 10a, 10b inner cylinder portion

[0055] 11a, 11b mounting boss portion

[0056] 12a, 12b barrel portion

[0057] 13a, 13b bottom portion

[0058] 14a, 14b bolt insertion hole

[0059] 15a, 15b side rib

[0060] 16a, 16b side rib

[0061] 17 center rib

[0062] 18a, 18b thinning portion

[0063] 19 inner side pad support portion

[0064] 20 inner side engagement protrusion

[0065] 21a, 21b outer cylinder portion

[0066] 22a, 22b barrel portion

[0067] 23a, 23b bottom portion

[0068] 24 auxiliary rib

[0069] 25 main rib

[0070] 26 outer side pad support portion

[0071] 27 outer side engagement protrusion

[0072] 28 recessed portion

[0073] 29 first beam portion

[0074] 30 second beam portion

[0075] 31 axial bottom portion

[0076] 32a, 32b circumferential wall portion

[0077] 33 radial bottom portion

[0078] 34 boss connection portion

[0079] 35 Steps

[0080] 36 Axial extension

[0081] 37. Extending inwards from the circumference.

[0082] 38 weeks laterally extended portion

[0083] 39 Padding

[0084] 40 Backplate Detailed Implementation

[0085] [First Example of Implementation]

[0086] use Figures 1 to 11 The first example of the implementation method will be described.

[0087] The opposed piston type disc brake device 1 in this example is used as a component for automobiles and includes a caliper 2 and a pair of pads 3 (inner pad and outer pad).

[0088] In this specification and claims, unless otherwise specified, "axial," "circumferential," and "radial" refer to the disc-shaped rotor 4 (see reference). Figure 1 The axial, circumferential, and radial directions of the disc brake 1. Furthermore, the circumferential inner side refers to the circumferential central side of the opposed piston type disc brake 1, and the circumferential outer side refers to the circumferential sides of the opposed piston type disc brake 1. Additionally, the rotating-in side refers to the side of the circumferential outer side where the rotor 4, rotating with the wheel while the vehicle is moving forward, enters the inner side of the caliper 2, and the rotating-out side refers to the side of the circumferential outer side where the rotor 4 disengages from the outer side of the caliper 2.

[0089] [calipers]

[0090] The caliper 2 is configured to cover the rotor 4 from the radial outside and supports a pair of bushings 3 so that they can move axially ( Figure 1 Up and down directions Figure 2 and Figure 3 The direction of the inside and outside, Figure 4 and Figure 5 The caliper 2 is integrally formed by casting and processing raw materials such as light alloys such as aluminum alloys or iron alloys.

[0091] The caliper 2 has a generally bow shape when viewed axially, and includes: an inner body 5 and an outer body 6, configured to clamp the rotor 4 from both sides axially; a turn-in side bridge 7 and a turn-out side bridge 8, which axially connect the two outer circumferential ends of the inner body 5 and the outer body 6; and a center bridge 9, which axially connects the middle circumferential portions of the inner body 5 and the outer body 6.

[0092] <Internal Body>

[0093] The inner body 5 is disposed on the axially inner side of the rotor 4. The inner body 5 has two inner cylinder portions 10a, 10b and two mounting boss portions 11a, 11b.

[0094] The inner cylinder portions 10a, 10b are disposed separately in the circumferential direction. The inner cylinder portions 10a, 10b are each configured as a bottomed cylindrical shape and have a cylindrical cylinder space inside. The inner cylinder portions 10a, 10b are each disposed at a circumferential intermediate portion of the inner body 5 and open on the axially outer side of the inner body 5 opposite the rotor 4. On the axially inner side of the inner body 5, a portion of the outer shape of the bottomed cylindrical inner cylinder portions 10a, 10b is exposed. Specifically, on the axially inner side of the inner body 5, the axially inner side portions of the cylinder portions 12a, 12b and the circular bottom portions 13a, 13b that constitute the inner cylinder portions 10a, 10b are exposed. In the inner cylinder portions 10a, 10b, an unillustrated inner piston is fitted in a manner so as to be axially displaceable.

[0095] The mounting boss portions 11a, 11b are disposed on both the outer sides in the circumferential direction of the inner cylinder portions 10a, 10b. Therefore, the mounting boss portions 11a, 11b are disposed on both the outer sides in the circumferential direction of the inner body 5. The mounting boss portions 11a, 11b each have a substantially cylindrical shape and have bolt insertion holes 14a, 14b formed inside that pass through in the radial direction. The caliper 2 directly fixes unillustrated bolts that are inserted through the bolt insertion holes 14a, 14b from the radially outer side to knuckles of a suspension device that constitutes a vehicle body, or fixes the bolts to the knuckles of the suspension device that constitutes the vehicle body via an unillustrated adapter. Therefore, the end faces on the radially inner sides of the respective mounting boss portions 11a, 11b function as seating surfaces. Also, the caliper 2 of this example is a caliper of the radial mounting type.

[0096] The inner body 5 has a total of four side ribs 15a, 15b, 16a, 16b and one central rib 17 on the axially inner side. The inner body 5 has two side ribs 15a, 15b, 16a, 16b on each of the outer sides in the circumferential direction and has the central rib 17 on the intermediate portion in the circumferential direction. The side ribs 15a, 15b, 16a, 16b and the central rib 17 are thick wall portions having a greater wall thickness than other portions (raised toward the axially inner side). Therefore, in the inner body 5, the wall thickness is increased and the rigidity is improved in portions where the side ribs 15a, 15b, 16a, 16b and the central rib 17 are respectively provided.

[0097] The side ribs 15a, 15b are provided on the rotor 4 side in the axially inner side surface of the inner body 5. Figure 1 and Figure 2The side ribs 15a, 15b are respectively elongated in the circumferential direction and arranged apart from each other in the radial direction. In other words, the side ribs 15a, 15b have a thin portion 18a recessed in the axial direction between them. The side ribs 15a, 15b are arranged non-parallel to each other. The side ribs 15a, 15b are respectively elongated toward the center axis O10a of the inner cylinder portion 10a. The side ribs 15a, 15b connect the mounting boss portion 11a arranged on the turn-in side and the axial inner side portion of the inner cylinder portion 10a arranged adjacent to the circumferential inner side of the mounting boss portion 11a in the circumferential direction.

[0098] The side ribs 16a, 16b are arranged on the circumferential outer side of the axial inner side surface of the inner body 5 on the turn-out side (right side in FIG. 1). The side ribs 16a, 16b are respectively elongated in the circumferential direction and arranged apart from each other in the radial direction. In other words, the side ribs 16a, 16b have a thin portion 18b recessed in the axial direction between them. The side ribs 16a, 16b are arranged non-parallel to each other. The side ribs 16a, 16b are respectively elongated toward the center axis O10b of the inner cylinder portion 10b. The side ribs 16a, 16b connect the mounting boss portion 11b arranged on the turn-out side and the axial inner side portion of the inner cylinder portion 10b arranged adjacent to the circumferential inner side of the mounting boss portion 11b in the circumferential direction. Figure 1 Figure 2 The side ribs 16a, 16b are arranged on the circumferential outer side of the axial inner side surface of the inner body 5 on the turn-out side (right side in FIG. 1). The side ribs 16a, 16b are respectively elongated in the circumferential direction and arranged apart from each other in the radial direction. In other words, the side ribs 16a, 16b have a thin portion 18b recessed in the axial direction between them. The side ribs 16a, 16b are arranged non-parallel to each other. The side ribs 16a, 16b are respectively elongated toward the center axis O10b of the inner cylinder portion 10b. The side ribs 16a, 16b connect the mounting boss portion 11b arranged on the turn-out side and the axial inner side portion of the inner cylinder portion 10b arranged adjacent to the circumferential inner side of the mounting boss portion 11b in the circumferential direction.

[0099] The central rib 17 is arranged on the circumferential middle portion of the axial inner side surface of the inner body 5. The central rib 17 is elongated in the circumferential direction and covers the radial middle portion of the bottom portion 13a, 13b of each of the inner cylinder portions 10a, 10b from the axial inner side in a manner traversing in the circumferential direction. Therefore, the radial outer side portion and the radial inner side portion of the bottom portion 13a, 13b of each of the inner cylinder portions 10a, 10b are not covered by the central rib 17 but overflow from the central rib 17 in the radial direction, respectively. The end portions on both circumferential outer sides of the central rib 17 are respectively connected to the end portion arranged on the circumferential inner side of the side rib 15b on the turn-in side and the end portion arranged on the circumferential inner side of the side rib 16b on the turn-out side.

[0100] In the assembled state of the opposed-piston type disc brake device 1, the pad 3 arranged on the axial inner side of the rotor 4 is supported so as to be movable in the axial direction with respect to the inner body 5. Therefore, the inner pad support portions 19 are respectively protruded in the axial direction on both circumferential outer side portions of the axial outer side surface of the inner body 5. In addition, the inner pad support portions 19 have the inner engagement protrusions 20 protruding toward the circumferential inner side on the radial inner side portions.

[0101] [Outer Body]

[0102] The outer body 6 is arranged on the axial outer side of the rotor 4. The outer body 6 has two outer cylinder portions 21a, 21b.

[0103] ​The outer cylinder portions 21a, 21b are disposed separately in the circumferential direction. The outer cylinder portions 21a, 21b are disposed in the circumferential direction intermediate portion of the outer body 6, and open on the axially inner side surface of the outer body 6 opposite the rotor 4. On the axially outer side surface of the outer body 6, a portion of the outer shape of the outer cylinder portions 21a, 21b, which are bottomed cylindrical, is exposed. Specifically, on the axially outer side surface of the outer body 6, the axially outer side portions of the cylinder portions 22a, 22b, which constitute the outer cylinder portions 21a, 21b, and the circular bottom portions 23a, 23b are exposed. In the outer cylinder portions 21a, 21b, an outer piston, not shown, is fitted so as to be axially displaceable.

[0104] The outer body 6 has one auxiliary rib 24 and one main rib 25 on the axially outer side surface. In this example, the auxiliary rib 24 is provided on the circumferential outer side portion of the radially outer side portion of the outer body 6 on the rotation-out side, and the main rib 25 is provided on the radially intermediate portion of the outer body 6. The auxiliary rib 24 and the main rib 25 are thick wall portions having a greater wall thickness than other portions (raised toward the axially outer side). Therefore, in the outer body 6, the wall thickness is increased, and the rigidity is improved, in the portions in which the auxiliary rib 24 and the main rib 25 are respectively provided.

[0105] The auxiliary rib 24 is elongated in the circumferential direction, and elongated in the direction approaching the central axis O21b of the outer cylinder portion 21b. The auxiliary rib 24 links the axially outer side surface of the circumferential inner side portion of the rotation-out side side bridge 8 and the axially outer side portion of the outer cylinder portion 21b in the circumferential direction.

[0106] The main rib 25 is provided on the axially outer side surface of the outer body 6 on the radially intermediate portion over the entire circumferential length. The main rib 25 is elongated in the circumferential direction, and covers the radially intermediate portion of the bottom portion 23a, 23b of each of the outer cylinder portions 21a, 21b from the axially outer side in a manner that traverses in the circumferential direction. Therefore, the radially outer side portion and the radially inner side portion of the bottom portion 23a, 23b of the outer cylinder portions 21a, 21b are not covered by the main rib 25, but respectively protrude radially from the main rib 25. With respect to the radial width of the main rib 25, the circumferential inner side portion covering the bottom portion 23a, 23b of the outer cylinder portions 21a, 21b is greater than the circumferential two outer side portions. The end portions of the circumferential two outer sides of the main rib 25 are respectively connected in the circumferential direction to the axially outer side surface of the circumferential outer side portion of the rotation-in side side bridge 7 and the axially outer side surface of the circumferential outer side portion of the rotation-out side side bridge 8.

[0107] In the assembled state of the opposed piston type disc brake device 1, the pad 3 disposed on the axially outer side of the rotor 4 is supported so as to be axially displaceable with respect to the outer body 6. Therefore, the outer side pad support portions 26, which respectively protrude in the axial direction, are provided on the circumferential two outer side portions of the axially inner side surface of the outer body 6. In addition, the outer side engagement protrusions 27, which protrude toward the circumferential inner side, are provided on the radially inner side portions of the outer side pad support portions 26.

[0108] 〈Side Bridge〉

[0109] The turn-in side bridge 7 and the turn-out side bridge 8 are respectively arranged so as to cover the rotor 4 from the radially outer side, and connect the end portions of the inner body 5 and the outer body 6 on the both circumferential sides in the axial direction. Specifically, the turn-in side bridge 7 connects the end portion of the inner body 5 on the circumferential outer side on the turn-in side and the end portion of the outer body 6 on the circumferential outer side on the turn-in side in the axial direction. On the contrary, the turn-out side bridge 8 connects the end portion of the inner body 5 on the circumferential outer side on the turn-out side and the end portion of the outer body 6 on the circumferential outer side on the turn-out side in the axial direction. The turn-in side bridge 7 and the turn-out side bridge 8 are respectively curved in a circular arc shape along the outer periphery of the rotor 4, and cover the rotor 4 from the radially outer side with a prescribed gap. The portion surrounded by the inner body 5, the outer body 6, and the turn-in side bridge 7 and the turn-out side bridge 8 becomes an opening portion in a substantially rectangular shape in plan view which penetrates in the radial direction.

[0110] The turn-in side bridge 7 and the turn-out side bridge 8 respectively have a recess 28, a first beam portion 29, and a second beam portion 30.

[0111] Recess

[0112] The recess 28 is provided in the circumferential intermediate portion of the turn-in side bridge 7 and the turn-out side bridge 8. The recess 28 is opened in the outer surface of the turn-in side bridge 7 and the turn-out side bridge 8. In this example, the recess 28 is respectively opened in the outer peripheral surface (radially outer surface) and the axially inner surface of the turn-in side bridge 7 and the turn-out side bridge 8. As shown in FIG. 2, the opening portion on the axially inner side of the recess 28 has a substantially rounded triangular shape. As shown in FIG. 3, the opening portion on the radially outer side of the recess 28 has a substantially oblong shape. Figure 2 Figure 1

[0113] The recess 28 is a groove elongated in the axial direction, and is provided in the axially inner half of the turn-in side bridge 7 and the turn-out side bridge 8.

[0114] The recess 28 has an axially bottom portion 31 in the axially outer end portion, circumferential wall portions 32a and 32b on both circumferential sides, and a radially bottom portion 33 in the radially inner end portion.

[0115] The axially bottom portion 31 is located in the axially intermediate portion of the turn-in side bridge 7 and the turn-out side bridge 8. In this example, the axially bottom portion 31 of the recess 28 provided in the turn-in side bridge 7 is arranged at substantially the same axial position as the axially inner surface of the outer body 6. The axially bottom portion 31 of the recess 28 provided in the turn-out side bridge 8 is located at a position axially inner than the axially bottom portion 31 of the recess 28 provided in the turn-in side bridge 7. That is, the axial length of the recess 28 provided in the turn-in side bridge 7 is longer than the axial length of the recess 28 provided in the turn-out side bridge 8. The reason for this is that in the caliper 2, higher rigidity is required in the turn-out side portion than in the turn-in side portion, and the deformation mode is different in the turn-in side portion and the turn-out side portion of the caliper 2.

[0116] ​​The circumferential wall portion 32a, located on the outer circumferential side, is arranged substantially parallel to the outer circumferential surfaces of the turning-in side bridge 7 and the turning-out side bridge 8. In contrast, the circumferential wall portion 32b, located on the inner circumferential side, is slightly inclined relative to the central axis O11 of the mounting boss portions 11a and 11b in a direction that is more radially inward and more circumferentially outward.

[0117] The radial bottom 33 is located at the radial midpoint between the inward-facing side bridge 7 and the outward-facing side bridge 8. In this example, the radial bottom 33 is located slightly radially outward from the central axes O10a and O10b of the inner cylinder portions 10a and 10b. The radial bottom 33 smoothly connects the radially inner ends of the circumferential wall portions 32a and 32b to each other circumferentially.

[0118] The axial bottom 31, circumferential wall portions 32a, 32b, and radial bottom 33 constituting the inner surface of the recess 28 are smoothly connected to each other. That is, the inner surface of the recess 28 is a smooth concave surface. However, in implementing the present invention, the inner surface of the recess may also be configured to include a flat surface.

[0119] The axial dimension of the recess 28 is larger than its circumferential dimension, and the axial dimension of the recess 28 is approximately half the axial dimension of the ingress side bridge 7 and the outgress side bridge 8. The radial dimension (depth) of the recess 28 is larger than half the radial dimension of the portion of the ingress side bridge 7 and the outgress side bridge 8 containing the recess 28. Therefore, the recess 28 is provided in the region from the radially outer portion to the radially middle portion of the ingress side bridge 7 and the outgress side bridge 8. As a result, the region from the radially outer portion to the radially middle portion in the circumferential middle portion of the ingress side bridge 7 and the outgress side bridge 8 is hollow.

[0120] like Figure 1 As shown, the central axis O28 of the recess 28 is arranged substantially parallel to the central axes O10a and O10b of the inner cylinder portions 10a and 10b. However, in implementing the present invention, the central axis of the recess may be inclined in a direction that is more circumferentially inward relative to the central axis of the inner cylinder portion as it moves outward. In this case, the central axis of the recess can be inclined at a rate greater than 0° and less than 30° in a direction that is more circumferentially inward relative to the central axis of the inner cylinder portion as it moves outward. As a result, the first beam portion and the second beam portion, which are arranged to sandwich the recess, can be extended in a manner close to the outer cylinder portion.

[0121] First and Second Beam Sections

[0122] The first beam portion 29 and the second beam portion 30 are each elongated in the axial direction, and are arranged so as to sandwich the recessed portion 28. In the present example, the first beam portion 29 and the second beam portion 30 are arranged at the outer circumferential side of the recessed portion 28. Specifically, the first beam portion 29 is arranged at the outer circumferential side of the recessed portion 28, and the second beam portion 30 is arranged at the inner circumferential side of the recessed portion 28. The first beam portion 29 and the second beam portion 30 are provided in the range from the radially outer portion to the radially intermediate portion in the half portion on the axial inner side of the turn-in side side bridge 7 and the turn-out side side bridge 8.

[0123] First beam portion

[0124] The first beam portion 29 is provided at the end portion on the outer circumferential side of the turn-in side side bridge 7 and the turn-out side side bridge 8. The inner circumferential side surface of the first beam portion 29 is the circumferential wall portion 32a of the recessed portion 28, and the outer circumferential side surface of the first beam portion 29 is a flat surface that constitutes the outer circumferential side surface of the turn-in side side bridge 7 and the turn-out side side bridge 8. The radially outer side surface of the first beam portion 29 is a convex curved surface that constitutes the outer circumferential surface of the turn-in side side bridge 7 and the turn-out side side bridge 8.

[0125] The end portion on the axial inner side of the first beam portion 29 is connected to the boss connecting portion 34 in the turn-in side side bridge 7 and the turn-out side side bridge 8, which is located in the vicinity of the outer circumferential side portion of the mounting boss portion 11a, 11b and is connected to the outer circumferential side portion of the mounting boss portion 11a, 11b. Thus, in the present example, the end portion on the axial inner side of the first beam portion 29 is connected to the mounting boss portion 11a, 11b via the boss connecting portion 34. In contrast, the end portion on the axial outer side of the first beam portion 29 is connected to the portion that constitutes the half portion on the axial outer side in the turn-in side side bridge 7 and the turn-out side side bridge 8.

[0126] The boss connecting portion 34 constitutes the axial inner side portion of the turn-in side side bridge 7 and the turn-out side side bridge 8, and is arranged at a position that is axially inner than the rotor 4.

[0127] The ridge line R29 between the radially outer side surface and the outer circumferential side surface of the outer surface of the first beam portion 29 is curved in a direction that is more radially inner and circumferentially inner as it goes toward the axial inner side, and is smoothly connected to the ridge line R34 on the outer circumferential side of the boss connecting portion 34. The ridge line R34 on the outer circumferential side of the boss connecting portion 34 is elongated in a direction that is more radially inner and circumferentially inner as it goes toward the axial inner side, and is connected to the end portion on the radially inner side of the mounting boss portion 11a, 11b. Thus, in the present example, the ridge line R29 of the first beam portion 29 is connected to the end portion on the radially inner side of the mounting boss portion 11a, 11b via the ridge line R34 of the boss connecting portion 34. Specifically, the ridge line R29 of the first beam portion 29 is connected to the outer circumferential side portion of the end portion on the radially inner side in the outer circumferential side surface of the mounting boss portion 11a, 11b via the ridge line R34 of the boss connecting portion 34.

[0128] The circumferential width of the first beam portion 29 is approximately constant in the axial direction. Since the radially outer surface of the first beam portion 29 is a convex surface that curves outward in a direction that is further outward in the axial direction, the radial width of the first beam portion 29 increases further outward in the axial direction. Therefore, the cross-sectional area of ​​the first beam portion 29 on the imaginary plane orthogonal to the central axis of the rotor 4 increases further outward in the axial direction.

[0129] The Second Beam Section

[0130] The second beam portion 30 is disposed in the circumferential middle portion of the entering side bridge 7 and the exit side bridge 8. The second beam portion 30 is positioned circumferentially inward compared to the first beam portion 29. The circumferential outer surface of the second beam portion 30 is the circumferential wall portion 32b of the recess 28, and the circumferential inner surface of the second beam portion 30 has a flat, stepped surface 35 that extends inward in a direction that is axially outward. The radial outer surface of the second beam portion 30 is a convex curved surface that forms the outer circumferential surface of the entering side bridge 7 and the exit side bridge 8. The axially inner end face of the second beam portion 30 forms the axially inner surface of the entering side bridge 7 and the exit side bridge 8.

[0131] The axially inner end of the second beam portion 30 is directly connected to the radially outer end of the mounting boss portions 11a and 11b. Specifically, the axially inner end of the second beam portion 30 is connected to the circumferentially outer portion of the radially outer end of the outer peripheral side surface of the mounting boss portions 11a and 11b. In contrast, the axially outer end of the second beam portion 30 is connected to the portion constituting the axially outer half of the turning-in side bridge 7 and the turning-out side bridge 8.

[0132] The stepped surface 35 constituting the circumferential inner side of the second beam portion 30 is inclined towards the circumferential inner side as it moves outward relative to the central axes O10a and O10b of the inner cylinder portions 10a and 10b. Therefore, the circumferential width of the second beam portion 30 increases as it moves outward. Furthermore, since the radially outer side of the second beam portion 30 is a convex surface that curves outward radially as it moves outward, the radial width of the second beam portion 30 also increases as it moves outward. Therefore, the cross-sectional area of ​​the second beam portion 30 on the imaginary plane orthogonal to the central axis of the rotor 4 increases as it moves outward.

[0133] like Figure 7 and Figure 8 As shown, the inward-facing side bridge 7 and the outward-facing side bridge 8 also have an axially extending portion 36, a circumferentially inward extending portion 37 and a circumferentially outward extending portion 38 at the opening of the recess 28.

[0134] like Figure 7As shown, the axial extension 36 is provided on the outer axial side of the opening of the recess 28, extending in the direction that reduces the opening area of ​​the recess 28, i.e., axially inward. That is, the axial extension 36 is provided along the radially outer end of the axial bottom 31 of the recess 28. The axial extension amount of the axial extension 36 is approximately 5% to 30% of the axial dimension of the recess 28. The radial thickness of the axial extension 36 is approximately 10% to 50% of the radial depth of the recess 28.

[0135] like Figure 8 As shown, the circumferentially inwardly extending portion 37 is provided in the circumferentially inward portion of the opening of the recess 28, extending outwardly in the direction that reduces the opening area of ​​the recess 28. Specifically, the circumferentially inwardly extending portion 37 is provided at its radially outer end along the circumferentially outer side surface of the second beam portion 30 (the circumferential wall portion 32b of the recess 28). The circumferential extension amount of the circumferentially inwardly extending portion 37 is smaller than the extension amount of the axially extending portion 36, and is approximately 10% to 35% of the circumferential dimension of the recess 28. The radial thickness of the circumferentially inwardly extending portion 37 is approximately the same as the radial thickness of the axially extending portion 36.

[0136] like Figure 8 As shown, the circumferentially outward protrusion 38 is provided in the circumferentially outward portion of the opening of the recess 28, extending in the direction of reducing the opening area of ​​the recess 28, i.e., circumferentially inward. That is, the circumferentially outward protrusion 38 is provided at the radially outer end of the circumferentially inner side surface of the first beam portion 29 (circumferential wall portion 32a of the recess 28). The circumferential extension amount of the circumferentially outward protrusion 38 is approximately the same as, or greater than, the circumferential extension amount of the circumferentially inner protrusion 37, and is approximately 10% to 45% of the circumferential dimension of the recess 28. The radial thickness of the circumferentially outward protrusion 38 is approximately the same as the radial thickness of the axially protruding portion 36 and the circumferentially inner protrusion 37.

[0137] The ends of the circumferential sides of the axial extension 36 are smoothly connected to the axial inner end of the circumferential inner extension 37 and the axial inner end of the circumferential outer extension 38.

[0138] In this example, the opening of the recess 28 has an axially extending portion 36, a circumferentially inward extending portion 37, and a circumferentially outward extending portion 38. Therefore, compared with the case where these axially extending portions 36, circumferentially inward extending portions 37, and circumferentially outward extending portions 38 are not present, the opening (opening area) of the recess 28 is smaller.

[0139] The center bridge 9 is disposed at a position radially outward of the outer periphery of the rotor 4. The center bridge 9 is disposed in a circumferential direction at a portion between the turn-in side bridge 7 and the turn-out side bridge 8, and axially links the circumferential direction intermediate portions of the inner body 5 and the outer body 6 to each other. The axially both side portions of the center bridge 9 have a two-web shape. The axially inner end portion of the center bridge 9 is connected to the radially outer portions of the pair of inner cylinder portions 10a, 10b. The axially outer end portion of the center bridge 9 is connected to the radially outer portions of the pair of outer cylinder portions 21a, 21b.

[0140] The pair of pads 3 are each composed of a pad (friction material) 39 and a metal back plate (pressure plate) 40 that supports the back surface of the pad 39.

[0141] In the present example, the pad 3 disposed axially inward of the rotor 4 (inner pad) is disposed between the pair of inner pad support portions 19, and the circumferential direction both outer end portions of the radially inner portions of the back plate 40 that constitutes the pad 3 are engaged with the pair of inner engagement protrusions 20 in a manner that allows axial movement. Thus, the pad 3 is supported so as to be axially movable with respect to the inner body 5.

[0142] In addition, the pad 3 disposed axially outward of the rotor 4 (outer pad) is disposed between the pair of outer pad support portions 26, and the circumferential direction both outer end portions of the radially inner portions of the back plate 40 that constitutes the pad 3 are engaged with the pair of outer engagement protrusions 27 in a manner that allows axial movement. Thus, the pad 3 is supported so as to be axially movable with respect to the outer body 6.

[0143] In addition, although not shown, a pad clip can be interposed between the circumferential direction both outer surfaces of the back plate 40 that respectively constitutes the pair of pads 3 and the circumferential direction inner surfaces of the inner pad support portions 19 and the outer pad support portions 26.

[0144] In the case of the opposed piston type disc brake device 1 of the present example described above, at the time of braking, brake oil is fed from the master cylinder to the inner cylinder portions 10a, 10b and the outer cylinder portions 21a, 21b, respectively. Thus, the inner pistons respectively fitted in the inner cylinder portions 10a, 10b are pushed in the axial direction, and the pad 3 supported by the inner body 5 is pressed against the axially inner surface of the rotor 4. Similarly, the outer pistons respectively fitted in the outer cylinder portions 21a, 21b are pushed in the axial direction, and the pad 3 supported by the outer body 6 is pressed against the axially outer surface of the rotor 4. As a result, the rotor 4 is strongly sandwiched from both axial sides by the pair of pads 3, and braking of the vehicle is performed.

[0145] In particular, in the case of the present example, regarding the radially mounted caliper 2 that constitutes the opposed piston type disc brake device 1, it is possible to achieve both the securing of rigidity and weight reduction.

[0146] The mounting boss portions 11a, 11b provided in the inner body 5 of the caliper 2 of this example are fixedly coupled to the knuckle. Therefore, when the caliper 2 is braked, there is a tendency for the outer body 6 to elastically deform in such a manner as to move away from the inner body 5 in the axial direction. When the caliper 2 elastically deforms in this manner, in the turn-in side side bridge 7 and the turn-out side side bridge 8, the axial tensile force acts on the radially inner side portion, and, in contrast, the axial compressive force tends to act on the radially outer side portion.

[0147] In this example, by forming the recessed portions 28 in the turn-in side side bridge 7 and the turn-out side side bridge 8, respectively, the radially intermediate portions in which the axial tensile force and the axial compressive force at the time of braking are both difficult to act are configured to be hollow (thinned) in the turn-in side side bridge 7 and the turn-out side side bridge 8. Therefore, according to the caliper 2 of this example, it is possible to achieve weight reduction while suppressing a decrease in rigidity.

[0148] In other words, the recessed portions 28 are not through holes that pass through the turn-in side side bridge 7 and the turn-out side side bridge 8 in the radial direction, respectively, but rather, the recessed portions 28 have radial bottoms 33 in the radially intermediate portions of the turn-in side side bridge 7 and the turn-out side side bridge 8. Therefore, by providing the recessed portions 28, it is possible to not decrease the axial tensile rigidity of the turn-in side side bridge 7 and the turn-out side side bridge 8. Therefore, it is possible to achieve weight reduction without decreasing the axial tensile rigidity of the turn-in side side bridge 7 and the turn-out side side bridge 8.

[0149] In addition, the recessed portions 28 are not through holes that pass through the turn-in side side bridge 7 and the turn-out side side bridge 8 in the axial direction, respectively, but rather, the recessed portions 28 have axial bottoms 31 in the axially intermediate portions of the turn-in side side bridge 7 and the turn-out side side bridge 8. Therefore, by providing the recessed portions 28, it is possible to not decrease the rigidity of the axially outer side portions of the turn-in side side bridge 7 and the turn-out side side bridge 8.

[0150] The recessed portions 28 are open at the outer surfaces of the turn-in side side bridge 7 and the turn-out side side bridge 8, and are also formed in the radially outer side portions of the turn-in side side bridge 7 and the turn-out side side bridge 8. Therefore, providing the recessed portions 28 is disadvantageous in terms of ensuring the rigidity against the axial compressive force of the turn-in side side bridge 7 and the turn-out side side bridge 8. However, in this example, the first beam portion 29 and the second beam portion 30 are provided in such a manner as to sandwich the recessed portions 28 from both sides, the end portion on the axially inner side of the first beam portion 29 is connected to the mounting boss portions 11a, 11b via the boss connecting portion 34, and the end portion on the axially inner side of the second beam portion 30 is directly connected to the mounting boss portions 11a, 11b.

[0151] The mounting boss portions 11a and 11b are portions that are fixed in conjunction with the knuckle and are portions that are less likely to be elastically deformed at the time of braking than other portions of the caliper 2. Therefore, displacement of the end portions on the inner side in the axial direction of the first beam portion 29 and the end portions on the inner side in the axial direction of the second beam portion 30 in the axial direction at the time of braking can be suppressed. Therefore, according to the caliper 2 of the present example, the compressive force in the axial direction acting on the inboard-side wheel 7 and the outboard-side wheel 8 can be effectively supported by the first beam portion 29 and the second beam portion 30, and thus the rigidity in the axial direction of the inboard-side wheel 7 and the outboard-side wheel 8 can be sufficiently ensured. As a result, according to the caliper 2 of the present example, both the rigidity and the weight reduction can be achieved.

[0152] Further, according to the caliper 2 of the present example, elastic deformation at the time of braking can be suppressed, and thus a desired braking force can be obtained with the opposed-piston disc brake device 1.

[0153] Further, the ridge line R29 of the first beam portion 29 is connected to the end portions on the inner side in the radial direction of the mounting boss portions 11a and 11b via the ridge line R34 of the boss connecting portion 34, and the end portions on the inner side in the axial direction of the second beam portion 30 are directly connected to the end portions on the outer side in the radial direction of the mounting boss portions 11a and 11b. The end portions on the inner side in the radial direction and the end portions on the outer side in the radial direction of the mounting boss portions 11a and 11b are portions that are sandwiched in the radial direction between the head portions of the bolts inserted through the bolt insertion holes 14a and 14b and the knuckle (or the adapter), and are portions that are less likely to be elastically deformed at the time of braking even in the mounting boss portions 11a and 11b. Therefore, displacement of the end portions on the inner side in the axial direction of the first beam portion 29 and the end portions on the inner side in the axial direction of the second beam portion 30 in the axial direction at the time of braking can be effectively suppressed. Therefore, the rigidity in the axial direction of the inboard-side wheel 7 and the outboard-side wheel 8 can be sufficiently ensured.

[0154] Further, the cross-sectional area of each of the first beam portion 29 and the second beam portion 30 is made larger toward the outer side in the axial direction. Therefore, the second moment of area of the first beam portion 29 and the second beam portion 30 can be made larger toward the outer side in the axial direction of the first beam portion 29 and the second beam portion 30, and thus the amount of elastic deformation (deflection amount) of the first beam portion 29 and the second beam portion 30 can be reduced. Therefore, elastic deformation of the caliper 2 at the time of braking can be suppressed.

[0155] Further, a circumferential inner side protruding portion 37 is provided on the inner side in the circumferential direction of the opening of the recess 28, and a circumferential outer side protruding portion 38 is provided on the outer side in the circumferential direction of the opening of the recess 28. The circumferential inner side protruding portion 37 and the circumferential outer side protruding portion 38 can be considered as part of the first beam portion 29 and the second beam portion 30, and thus the cross-sectional area of the end portion on the outer side in the radial direction of each of the first beam portion 29 and the second beam portion 30 can be increased. Therefore, compared to a case where the circumferential inner side protruding portion 37 and the circumferential outer side protruding portion 38 are not provided, the second moment of area of the cross section of the first beam portion 29 and the second beam portion 30 can be increased, and the elastic deformation amount of the first beam portion 29 and the second beam portion 30 can be reduced.

[0156] Further, an axial protruding portion 36 is provided on the outer side in the axial direction of the opening of the recess 28. Thereby, the rigidity in the circumferential direction of the outer side in the axial direction of the turn-in side bridge 7 and the turn-out side bridge 8 can be increased. Therefore, the outer side in the axial direction of the turn-in side bridge 7 and the turn-out side bridge 8 can be suppressed from deforming in the circumferential direction. Further, the ends on both sides in the circumferential direction of the axial protruding portion 36 are connected to the ends on the inner side in the axial direction of the circumferential inner side protruding portion 37 and the circumferential outer side protruding portion 38, respectively. Therefore, the compression force acting in the axial direction of the turn-in side bridge 7 and the turn-out side bridge 8 can also be supported by the first beam portion 29 and the second beam portion 30 through the axial protruding portion 36.

[0157] Further, in the present example, the mounting boss portions 11a, 11b are circumferentially connected to the inner side in the axial direction of the inner cylinder portions 10a, 10b by the side ribs 15a, 15b, 16a, 16b each of which is provided on both outer sides in the circumferential direction of the inner side surface in the axial direction of the inner body 5. Therefore, the rigidity in the axial direction of the bottom portions 13a, 13b of the inner cylinder portions 10a, 10b can be increased. Therefore, during braking, the bottom portions 13a, 13b of the inner cylinder portions 10a, 10b can be suppressed from elastically deforming toward the inner side in the axial direction, and the inner body 5 and the outer body 6 can be suppressed from elastically deforming in a direction in which they are separated from each other in the axial direction. Further, the rigidity in the circumferential direction of the inner body 5 can also be increased, and thus, during braking, the outer body 6 can be suppressed from elastically deforming in a manner in which it is displaced in the circumferential direction (the direction of rotation of the rotor 4), and vibration and noise can also be suppressed.

[0158] Further, the central rib 17 covers the bottom portions 13a, 13b of the inner cylinder portions 10a, 10b from the inner side in the axial direction. Therefore, the rigidity in the axial direction and the circumferential direction of the inner body 5 can be increased. In particular, the central rib 17 covers the radially intermediate portions of the bottom portions 13a, 13b of the inner cylinder portions 10a, 10b from the inner side in the axial direction in a manner in which it traverses in the circumferential direction, and thus, during braking, the bottom portions 13a, 13b of the inner cylinder portions 10a, 10b can be effectively suppressed from elastically deforming toward the inner side in the axial direction.

[0159] Further, the pair of side ribs 15a, 15b are arranged non-parallel to each other, and the pair of side ribs 16a, 16b are arranged non-parallel to each other, so that the side ribs 15a, 15b, 16a, 16b are respectively elongated in a direction approaching the center axes O10a, O10b of the inner cylinder portions 10a, 10b. Thus, the torsional rigidity of the inner body 5 can be improved.

[0160] Further, the end portions of the respective circumferential outer sides of the side ribs 15a, 16a are connected to the end portions of the radial outer sides of the mounting boss portions 11a, 11b, and the end portions of the respective circumferential outer sides of the side ribs 15b, 16b are connected to the end portions of the radial inner sides of the mounting boss portions 11a, 11b. Thus, the improvement of the rigidity of the side ribs 15a, 15b, 16a, 16b can be achieved. Therefore, the improvement of the rigidity of the inner body 5 is facilitated.

[0161] Further, the radial intermediate portions of the bottom portions 23a, 23b of the outer cylinder portions 21a, 21b are covered from the axial outer side in a circumferential direction by the main rib 25 provided to the axial outer side surface of the outer body 6, so that the elastic deformation of the bottom portions 23a, 23b of the outer cylinder portions 21a, 21b to the axial outer side at the time of braking can be effectively suppressed. Further, the turn-out side side bridge 8 and the outer cylinder portion 21b are connected in the circumferential direction by the auxiliary rib 24, so that the rigidity in the axial direction of the outer cylinder portion 21b can be improved.

[0162] The above describes the embodiments of the present application, but the present application is not limited to this, and can be appropriately changed within the scope of the technical idea of the present application.

[0163] In the embodiments, the case where the recess, the first beam portion, and the second beam portion are provided to the turn-in side side bridge and the turn-out side side bridge, respectively, is described, but in the case of implementing the present application, the recess, the first beam portion, and the second beam portion can be provided to either one of the turn-in side side bridge and the turn-out side side bridge.

[0164] Further, in the embodiments, the case where the recess is opened to the outer peripheral surface and the axial inner side surface of the side bridge is described, but in the case of implementing the present application, the opening position of the recess is not particularly limited. For example, the recess can be opened only to the outer peripheral surface or the circumferential outer side surface of the side bridge, or can be opened to the outer peripheral surface and the circumferential outer side surface of the side bridge. In the case where the recess is opened only to the circumferential outer side surface of the side bridge, the first beam portion and the second beam portion are arranged in the radial direction with the recess interposed therebetween.

[0165] Further, in the embodiments, the case where the end portion of the axial inner side of the first beam portion is connected to the end portion of the radial inner side of the mounting boss portion via the boss connection portion is described, but in the case of implementing the present application, the end portion of the axial inner side of the first beam portion can be directly connected to the end portion of the radial inner side of the mounting boss portion.

[0166] In the embodiment, the axial extension, the circumferential inner extension, and the circumferential outer extension are provided at the opening of the recess, respectively. However, in the case of implementing the present application, the axial extension, the circumferential inner extension, and the circumferential outer extension can be omitted. Alternatively, any one or two of the axial extension, the circumferential inner extension, and the circumferential outer extension can be provided.

[0167] In the case of implementing the present application, the caliper for the opposed-piston disc brake can be a single-shell structure (monolithic structure) integrally formed of a material such as an aluminum alloy, or can be a structure in which the inner member and the outer member are coupled by bolts. In addition, the number of the inner cylinder portion and the outer cylinder portion is not limited to two as described in the embodiment, and can be one or more than three.

Claims

1. A caliper for a disc brake of the opposed-piston type, characterized in that, Possessing: an inner body configured on the inner side in the axial direction of a rotor, and having at least one or more inner cylinder portions, and a pair of mounting boss portions configured on both outer sides in the circumferential direction of the at least one or more inner cylinder portions, and each formed with a bolt insertion hole that penetrates in the radial direction; an outer body configured on the outer side in the axial direction of the rotor, and having at least one or more outer cylinder portions; and a pair of side bridges configured in a manner that covers the rotor from the radial outer side, and axially links the end portions of both outer sides in the circumferential direction of the inner body with the end portions of both outer sides in the circumferential direction of the outer body, at least one side bridge of the pair of side bridges has a recess portion that is elongated in the axial direction and opens on the outer surface of the side bridge, and a first beam portion and a second beam portion that are configured sandwiching the recess portion from both sides, and the end portions of the axial inner sides of the first beam portion and the second beam portion are connected to the mounting boss portion directly or via a portion of the side bridge located in the vicinity of the mounting boss portion, the end portion of the axial inner side of the first beam portion is connected to the mounting boss portion via the boss connection portion, and the boss connection portion constitutes the axial inner side portion of the side bridge.

2. The caliper for a disc brake of an opposed piston type according to claim 1, wherein the end portion of the axial outer side of the recess portion has an axial bottom portion.

3. The caliper for a disc brake of an opposed piston type according to claim 1 or claim 2, wherein the recess portion opens to the outer peripheral surface and / or the circumferential outer side surface of the side bridge.

4. The caliper for a disc brake of an opposed piston type according to claim 1 or claim 2, wherein the recess portion opens to the axial inner side surface of the side bridge.

5. The caliper for a disc brake of an opposed piston type according to claim 1 or claim 2, wherein the ridge line of the first beam portion is linked to the end portion of the radial inner side of the mounting boss portion via the ridge line of the portion of the side bridge located in the vicinity of the mounting boss portion.

6. The caliper for a disc brake of an opposed piston type according to claim 1 or claim 2, wherein the second beam portion is directly connected to the end portion of the radial outer side of the mounting boss portion.

7. The caliper for a disc brake of an opposed piston type according to claim 1 or claim 2, wherein the first beam portion and the second beam portion are configured sandwiching the recess portion in the circumferential direction.

8. The caliper for a disc brake of an opposed piston type according to claim 1 or claim 2, wherein at least any one of the first beam portion and the second beam portion becomes larger in cross-sectional area as it goes toward the axial outer side.

9. The caliper for a disc brake of an opposed piston type according to claim 8, wherein the second beam portion becomes larger in circumferential direction width as it goes toward the axial outer side.

10. The caliper for a disc brake of an opposed piston type according to claim 8, wherein the first beam portion becomes larger in radial width as it goes toward the axial outer side.

11. The caliper for a disc brake of an opposed piston type according to claim 1 or claim 2, wherein The side bridge further has a protruding portion that protrudes toward a direction in which the opening area of the recess is reduced.

12. The caliper for an opposed-piston disc brake according to claim 11, characterized in that The protruding portion is provided at an axial outer side portion of the opening portion of the recess.

13. The caliper for an opposed-piston disc brake according to claim 11, characterized in that The protruding portion is provided at a circumferential inner side portion and / or a circumferential outer side portion of the opening portion of the recess.

14. The caliper for an opposed-piston disc brake according to claim 1 or claim 2, characterized in that The central axis of the recess is inclined toward a direction in which the more toward the axial outer side, the more toward the circumferential inner side, with respect to the central axis of the inner cylinder portion.

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