Caliper

Abstract

To provide a caliper capable of more surely suppressing brake noise as an example.SOLUTION: A caliper according to an embodiment includes, for example, at least one piston assembly including a caliper body provided with at least one cylinder, a metal piston accommodated in the cylinder and provided with an internal space, a metal weight disposed in the internal space, and a support portion formed integrally with at least one of the piston and the weight, having lower rigidity than each of the piston and the weight, and directly supporting the weight such that the weight is swingable with respect to the piston.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to a caliper. [Background technology]

[0002] Conventionally, calipers that suppress brake squeal using a dynamic vibration absorber (dynamic damper) have been known. For example, such calipers have a piston, a weight placed inside the piston, and an elastic body made of a polymer material such as synthetic rubber interposed between the piston and the weight. The weight oscillates relative to the piston, allowing the caliper to suppress brake squeal (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-128478 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional designs, when temperature changes occur, the elastic polymer material experiences a larger change in spring constant than a metal piston or weight, which can cause the caliper to fail to suppress brake squeal at the desired frequency.

[0005] Therefore, the present invention has been made in consideration of the above, and provides a caliper that can more reliably suppress brake squeal. [Means for solving the problem]

[0006] A caliper according to an embodiment of the present invention includes, as an example, at least one piston assembly including: a caliper body having at least one cylinder; a metal piston housed in the cylinder and having an internal space; a metal weight disposed in the internal space; and a support portion integrally formed with at least one of the piston and the weight, having lower rigidity than the piston and the weight, and directly supporting the weight so that the weight can oscillate relative to the piston. Thus, as an example, the piston assembly allows the weight to oscillate relative to the piston without an elastic body made of a polymer material such as synthetic rubber or synthetic resin interposed between the weight and the piston. Furthermore, since the support portion is integrally formed with at least one of the piston and the weight, it is made of metal. Generally, metal has a spring constant that changes less with temperature than an elastic body made of a polymer material. Therefore, the caliper can damp vibrations by the oscillation of the weight and can suppress temperature-related changes in the natural frequency of the piston assembly. Therefore, the caliper can more reliably suppress brake squeal. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a bottom view showing a disc brake according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a part of the caliper of the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing a part of a caliper according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (First embodiment) The first embodiment will be described below with reference to FIGS. 1 and 2. In this specification, components according to the embodiment and descriptions of the components may be described using multiple expressions. The components and their descriptions are merely examples and are not limited by the expressions in this specification. The components may also be identified by names different from those in this specification. Furthermore, the components may also be described using expressions different from those in this specification.

[0009] In the following description, "inhibit" is defined as, for example, preventing an event, action, or effect from occurring or reducing the magnitude of an event, action, or effect.

[0010] Fig. 1 is a bottom view showing a disc brake 10 according to a first embodiment. As shown in Fig. 1, the disc brake 10 has a disc rotor 11, two brake pads 12, and a caliper 13. Fig. 1 schematically shows the disc rotor 11 by a two-dot chain line.

[0011] The disc rotor 11 is formed in a disk shape that is approximately perpendicular to the central axis Axd. The disc rotor 11 is connected to an axle and rotates integrally with the axle around the central axis Axd. The central axis Axd is, for example, the central axis of the axle of a vehicle on which the disc brake 10 is mounted, and is also the central axis of the disc rotor 11. However, the central axis Axd is not limited to this example.

[0012] For convenience, the axial direction, radial direction, and circumferential direction of the central axis Axd are defined herein. The axial direction is the direction along the central axis Axd. The radial direction is the direction perpendicular to the central axis Axd. The circumferential direction is the direction around the central axis Axd.

[0013] The two brake pads 12 are spaced apart from each other in the axial direction. The disc rotor 11 is disposed between the two brake pads 12. Each of the two brake pads 12 has a back plate 21, a lining 22, and a shim 23. However, the brake pads 12 are not limited to this example.

[0014] The back plate 21 is formed in a plate shape that is approximately perpendicular to the axial direction. The lining 22 is a friction material provided on one surface of the back plate 21. The lining 22 is disposed between the back plate 21 and the disc rotor 11. The shim 23 is provided on the other surface of the back plate 21 and reduces vibration during braking. Note that the shim 23 may be omitted.

[0015] 2 is a cross-sectional view showing a portion of the caliper 13 of the first embodiment. The caliper 13 of this embodiment is an opposed-type caliper. However, the caliper 13 is not limited to this example and may be, for example, a floating-type caliper. As shown in FIG. 2, the caliper 13 has a caliper body 31, a plurality of piston assemblies 32, and a plurality of seals 33.

[0016] The caliper body 31 is fixed to, for example, the body of the vehicle, so that the disc rotor 11 is rotatable relative to the caliper body 31. Note that the caliper body 31 may be fixed to another location.

[0017] The caliper body 31 is made of metal, for example, by casting. However, the caliper body 31 may be made of other materials and by other methods. As shown in FIG. 1, the caliper body 31 has two side walls 41 and a plurality of outer walls 42.

[0018] The two side walls 41 are disposed axially apart from each other. The disc rotor 11 and the brake pads 12 are disposed between the two side walls 41. The two side walls 41 axially cover a portion of the disc rotor 11. The caliper body 31 supports the brake pads 12 by, for example, pins so that the brake pads 12 are axially movable.

[0019] Each of the two side walls 41 has an inner surface 41a. The inner surface 41a is formed to be substantially flat and faces the axial direction. The inner surfaces 41a of the two side walls 41 face each other with a gap between them. The inner surfaces 41a face the shim 23 of the brake pad 12 and also face the disc rotor 11.

[0020] A plurality of cylinders 45 are provided on each of the two side walls 41. In this embodiment, three cylinders 45 are provided on each of the two side walls 41. The number of cylinders 45 is not limited to this example. The plurality of cylinders 45 are recesses that open to the inner surface 41a. That is, the cylinders 45 open toward the brake pads 12.

[0021] As shown in Figure 2, the axial direction includes a forward direction Df and a rearward direction Db. The forward direction Df is a direction along the central axis Axd. The rearward direction Db is a direction opposite to the forward direction Df. The cylinder 45 is recessed from the inner surface 41a of the side wall 41 in the rearward direction Db.

[0022] The forward direction Df and the rearward direction Db are defined for each of the two side walls 41. Therefore, the forward direction Df of one side wall 41 and the forward direction Df of the other side wall 41 are opposite directions to each other. Also, the rearward direction Db of one side wall 41 and the rearward direction Db of the other side wall 41 are opposite directions to each other.

[0023] Each of the multiple cylinders 45 is a substantially cylindrical hole extending along a central axis Axc. The diameters of the multiple cylinders 45 may be substantially the same or may be different from one another. The central axis Axc is the central axis of the cylinder 45. Therefore, each of the multiple cylinders 45 has a central axis Axc.

[0024] The central axis Axc of each of the cylinders 45 is substantially parallel to the central axis Axd of the disc rotor 11. Therefore, the axial directions (the forward direction Df and the rearward direction Db) are also directions along the central axis Axc.

[0025] The side wall 41 has a plurality of inner circumferential surfaces 45a and a plurality of bottom surfaces 45b. Each of the plurality of cylinders 45 is defined by the inner circumferential surface 45a and the bottom surface 45b. Note that the cylinders 45 are not limited to this example.

[0026] The inner circumferential surface 45a is a substantially cylindrical curved surface extending in the rear direction Db from the inner surface 41a of the side wall 41. The bottom surface 45b is connected to the end of the inner circumferential surface 45a in the rear direction Db, and faces the front direction Df as a whole.

[0027] 1, each of the multiple outer walls 42 is disposed between two side walls 41 and connected to the two side walls 41. In other words, the caliper body 31 is formed so as to straddle a portion of the disc rotor 11. The outer walls 42 cover a portion of the disc rotor 11 in the radial direction.

[0028] 2, the plurality of piston assemblies 32 are housed in the plurality of cylinders 45. Each of the plurality of piston assemblies 32 includes a piston 51, a weight 52, a support portion 53, and a bolt 54. The support portion 53 may also be referred to as a support column or a low-rigidity portion.

[0029] The piston 51 is a metal component. For example, the piston 51 is made of steel, cast iron, or an aluminum alloy. However, the material of the piston 51 is not limited to these examples. The piston 51 has two end faces 61 and 62, an outer circumferential surface 63, and an inner surface 64.

[0030] The end surface 61 is provided at an end of the piston 51 in the forward direction Df. The end surface 61 is formed to be substantially flat and faces the forward direction Df. The end surface 61 abuts against the shim 23 of the brake pad 12 and supports the brake pad 12.

[0031] The end surface 62 is located opposite the end surface 61. The end surface 62 is provided at an end of the piston 51 in the rear direction Db. The end surface 62 faces the rear direction Db as a whole. The end surface 62 of the piston 51 faces the bottom surface 45b of the side wall 41.

[0032] The outer peripheral surface 63 is a substantially cylindrical curved surface extending along the central axis Axc. The outer peripheral surface 63 of the piston 51 faces the inner peripheral surface 45a of the side wall 41. The diameter of the outer peripheral surface 63 is slightly shorter than the diameter of the inner peripheral surface 45a. That is, the piston 51 is accommodated in the cylinder 45 so as to be movable (slidable) in the axial direction.

[0033] A fluid chamber R is provided between an end face 62 of the piston 51 and a bottom surface 45b of the caliper body 31. The fluid chamber R is part of the cylinder 45. The fluid chamber R is filled with brake fluid and is connected to, for example, a master cylinder or a pump. A gap between an outer peripheral surface 63 of the piston 51 and an inner peripheral surface 45a of the caliper body 31 is sealed by a seal 33.

[0034] A portion of the piston 51, including the end face 61, is located outside the cylinder 45. That is, the piston 51 protrudes in the forward direction Df from the inner surface 41a of the side wall 41. Therefore, the brake pad 12 is spaced apart from the inner surface 41a of the side wall 41.

[0035] In this embodiment, the inner surface 64 has an inner circumferential surface 65 and a bottom surface 66. The inner circumferential surface 65 is a substantially cylindrical curved surface extending from the end surface 61 in the rear direction Db along the central axis Axc. The inner circumferential surface 65 is located on the opposite side of the outer circumferential surface 63. The inner circumferential surface 65 surrounds the central axis Axc and faces the central axis Axc. The bottom surface 66 is connected to the end of the inner circumferential surface 65 in the rear direction Db. The bottom surface 66 is formed substantially flat and faces the forward direction Df as a whole.

[0036] An internal space 67 is provided in the piston 51. The internal space 67 is defined by an inner surface 64. The internal space 67 opens to the end face 61. In other words, the internal space 67 is recessed from the end face 61 in the rear direction Db and is open to the outside of the piston 51. In this embodiment, the internal space 67 opens toward the brake pad 12 and is blocked by the brake pad 12.

[0037] The weight 52 is a metal component. For example, the weight 52 is made of steel, cast iron, or an aluminum alloy. However, the material of the weight 52 is not limited to this example. The material of the piston 51 and the material of the weight 52 may be the same or different. The weight 52 is disposed in the internal space 67 and is spaced apart from the inner surface 64.

[0038] The support portion 53 is formed integrally with the piston 51. That is, the support portion 53 is a metal portion. The support portion 53 protrudes in the forward direction Df from the bottom surface 66. Note that the support portion 53 is not limited to this example, and may be connected to the inner circumferential surface 65, for example.

[0039] The support portion 53 has a support surface 71. The support surface 71 is provided at an end of the support portion 53 in the forward direction Df. The support surface 71 abuts against the weight 52 and supports the weight 52. That is, the support portion 53 directly supports the weight 52.

[0040] If at least one of the piston 51 and the weight 52 is coated, the coating is interposed between the metal portion of the support part 53 and the metal portion of the weight 52. However, the coating is part of the piston 51 or the weight 52. Therefore, in this case as well, the support part 53 directly supports the weight 52.

[0041] In the present embodiment, the support portion 53 is formed in a substantially cylindrical shape extending along the central axis Axc. For this reason, a hole 75 is provided in the support portion 53. The hole 75 opens to the support surface 71 and is recessed from the support surface 71 in the rear direction Db. The hole 75 is provided over substantially the entire area of ​​the support portion 53 in the axial direction. However, the hole 75 is not limited to this example.

[0042] The outer diameter of the support portion 53 is smaller than the outer diameter of the weight 52. Therefore, the support portion 53 is spaced apart from the inner circumferential surface 65 of the piston 51. The support portion 53 further has an internal thread / nut thread 76 provided in the hole 75.

[0043] The support portion 53 has lower rigidity than the piston 51 and the weight 52. The support portion 53 also has a lower spring constant than the piston 51 and the weight 52. The rigidity and spring constant of the support portion 53 are set by, for example, the outer diameter, inner diameter, material, length, shape, and various designs of the support portion 53.

[0044] The bolt 54 has a screw shaft 81 and a screw head 82. The screw shaft 81 passes through the weight 52 and is fitted into the hole 75 of the support portion 53. A male screw (external thread / bolt thread) 85 is provided on the screw shaft 81. The male screw 85 is fitted into the female screw 76 of the support portion 53. The screw head 82 is provided on the end of the screw shaft 81 in the forward direction Df. The bolt 54 holds a part of the weight 52 between the screw head 82 and the support portion 53. In this way, the weight 52 is removably attached to the support portion 53 by the bolt 54. Note that, for example, if removal is not necessary or if it is necessary to prevent the bolt 54 from loosening, the bolt 54 may attach the weight 52 to the support portion 53 using a bolt adhesive or the like.

[0045] The multiple piston assemblies 32 include multiple piston assemblies 32A and 32B that are different from each other. The piston assembly 32A is one of the multiple piston assemblies 32. The piston assembly 32B is another of the multiple piston assemblies 32. Note that the multiple piston assemblies 32 may be identical to each other.

[0046] The weight 52, support 53, and bolt 54 of the piston assembly 32A are referred to as weight 52A, support 53A, and bolt 54A. The weight 52A has two end faces 101 and 102 and an outer circumferential surface 103.

[0047] The end surface 101 is provided at an end of the weight 52A in the forward direction Df. The end surface 101 is formed to be substantially flat and faces the forward direction Df. The end surface 101 is disposed in the internal space 67 and is closer to the bottom surface 66 than the end surface 61 of the piston 51. Therefore, the weight 52A is spaced apart from the brake pad 12.

[0048] The end surface 102 is located on the opposite side to the end surface 101. The end surface 102 is provided at the end of the weight 52A in the rear direction Db. The end surface 102 is formed to be approximately flat and faces the rear direction Db. The end surface 102 contacts the support surface 71 of the support portion 53. The end surface 102 is spaced apart from the bottom surface 66 of the piston 51.

[0049] Outer peripheral surface 103 is a substantially cylindrical curved surface extending along central axis Axc. Outer peripheral surface 103 of weight 52A faces inner peripheral surface 65 of piston 51. The diameter of outer peripheral surface 103 is smaller than the diameter of inner peripheral surface 65.

[0050] The weight 52A is provided with a recess 105. The recess 105 is recessed from the end face 101 in the rear direction Db along the central axis Axc. The weight 52A further has an inner circumferential surface 106 and a bottom surface 107 that define the recess 105.

[0051] The inner circumferential surface 106 is a substantially cylindrical curved surface extending from the end surface 101 in the rear direction Db along the central axis Axc. The inner circumferential surface 106 is located on the opposite side of the outer circumferential surface 103. The inner circumferential surface 106 surrounds the central axis Axc and faces the central axis Axc. The bottom surface 107 is connected to the end of the inner circumferential surface 106 in the rear direction Db. The bottom surface 107 is formed substantially flat and faces the forward direction Df as a whole.

[0052] An insertion hole 108 is provided in weight 52A. Insertion hole 108 extends forward from end face 102 along central axis Axc and communicates with recess 105. Screw shaft 81 of bolt 54A extends through insertion hole 108. Furthermore, screw head 82 of bolt 54A is positioned in recess 105 and contacts bottom surface 107. In this way, bolt 54A attaches weight 52A to support part 53A.

[0053] The screw head 82 of the bolt 54A is disposed in the internal space 67 and is closer to the bottom surface 66 than the end surface 61 of the piston 51. The screw head 82 of the bolt 54A is also closer to the bottom surface 66 than the end surface 101 of the weight 52A. Therefore, the bolt 54A is spaced apart from the brake pad 12.

[0054] The outer diameter of the support portion 53A is approximately constant. Furthermore, the difference between the inner diameter and the outer diameter of the support portion 53A (the thickness of the support portion 53A) is also approximately constant. Note that the support portion 53A is not limited to this example. The outer diameter of the support portion 53A is larger than the diameter of the insertion hole 108.

[0055] The weight 52, support 53, and bolt 54 of the piston assembly 32B are referred to as weight 52B, support 53B, and bolt 54B. Weight 52B has two end faces 111 and 112 and an outer circumferential surface 113.

[0056] The end surface 111 is provided at an end of the weight 52B in the forward direction Df. The end surface 111 is formed to be approximately flat and faces the forward direction Df. The end surface 111 is disposed in the internal space 67 and is closer to the bottom surface 66 than the end surface 61 of the piston 51. Therefore, the weight 52B is spaced apart from the brake pad 12.

[0057] The end surface 112 is located on the opposite side to the end surface 111. The end surface 112 is provided at the end of the weight 52B in the rear direction Db. The end surface 112 is formed to be approximately flat and faces in the rear direction Db. The end surface 112 is spaced apart from the bottom surface 66 of the piston 51.

[0058] The distance between end face 112 of weight 52B and bottom face 66 of piston 51 is shorter than the distance between end face 102 of weight 52A and bottom face 66 of piston 51. That is, weight 52B is longer than weight 52A in the axial direction.

[0059] The outer peripheral surface 113 is a substantially cylindrical curved surface extending along the central axis Axc. The outer peripheral surface 113 of the weight 52B faces the inner peripheral surface 65 of the piston 51. The diameter of the outer peripheral surface 113 is smaller than the diameter of the inner peripheral surface 65.

[0060] Weight 52B is provided with two recesses 121, 122. Recess 121 is recessed from end face 111 in the rear direction Db along the central axis Axc. Weight 52B further has an inner circumferential surface 125 and a bottom surface 126 that define recess 121. Recess 122 is recessed from end face 112 in the forward direction Df along the central axis Axc. Weight 52B further has an inner circumferential surface 127 and a bottom surface 128 that define recess 122.

[0061] Inner circumferential surface 125 is a substantially cylindrical curved surface that extends from end surface 111 in the rear direction Db along the central axis Axc. Inner circumferential surface 127 is a substantially cylindrical curved surface that extends from end surface 112 in the forward direction Df along the central axis Axc. Inner circumferential surfaces 125, 127 are located on the opposite side of outer circumferential surface 113. Inner circumferential surfaces 125, 127 surround the central axis Axc and face the central axis Axc.

[0062] The bottom surface 126 is connected to the end of the inner circumferential surface 125 in the rear direction Db. The bottom surface 126 is formed to be approximately flat and faces the front direction Df as a whole. The bottom surface 128 is connected to the end of the inner circumferential surface 127 in the front direction Df. The bottom surface 128 is formed to be approximately flat and faces the rear direction Db as a whole.

[0063] An insertion hole 129 is provided in the weight 52B. The insertion hole 129 extends in the axial direction along the central axis Axc and opens to the bottom surfaces 126, 128. The screw shaft 81 of the bolt 54B extends through the insertion hole 129.

[0064] The screw head 82 of the bolt 54B is disposed in the recess 121 and contacts the bottom surface 126. A portion of the support portion 53B is disposed in the recess 122. The support surface 71 of the support portion 53B contacts the bottom surface 128. In this way, the bolt 54B attaches the weight 52B to the support portion 53B. The inner peripheral surface 127 is spaced apart from the support portion 53B.

[0065] The screw head 82 of the bolt 54B is disposed in the internal space 67 and is closer to the bottom surface 66 than the end surface 61 of the piston 51. The screw head 82 of the bolt 54B is also closer to the bottom surface 66 than the end surface 111 of the weight 52B. Therefore, the bolt 54B is spaced apart from the brake pad 12.

[0066] The outer diameter and inner diameter of the support portion 53B are not uniform. The support portion 53B has an attachment portion 131 and an intervening portion 132. The attachment portion 131 and the intervening portion 132 are aligned in the axial direction. The attachment portion 131 has a support surface 71 and a female thread 76, and is attached to the weight 52B. The intervening portion 132 is provided between the attachment portion 131 and the bottom surface 66 of the piston 51.

[0067] The outer diameter of the intervening portion 132 is smaller than the outer diameter of the mounting portion 131. That is, the intervening portion 132 is thinner than the mounting portion 131. Furthermore, the inner diameter of the intervening portion 132 is also smaller than the inner diameter of the mounting portion 131. The thickness of the intervening portion 132 may be approximately the same as the thickness of the mounting portion 131, or may be thinner.

[0068] The threaded shaft 81 of the bolt 54B is attached to the attachment portion 131 but is spaced apart from the intervening portion 132. In other words, the threaded shaft 81 of the bolt 54B is not inserted into the hole 75 provided in the intervening portion 132. Note that a portion of the threaded shaft 81 may be inserted into the hole 75 provided in the intervening portion 132. Furthermore, the intervening portion 132 may be solid and the hole 75 may be omitted.

[0069] Bolt 54B is larger than bolt 54A. That is, the outer diameter of male thread 85 of bolt 54B is larger than the outer diameter of male thread 85 of bolt 54A. Furthermore, the diameter of screw head 82 of bolt 54B is larger than the diameter of screw head 82 of bolt 54A.

[0070] Increasing the outer diameter of the male thread 85 of bolt 54B makes the threaded shaft 81 of bolt 54B thicker. As a result, bolt 54B is stronger than bolt 54A. Furthermore, it becomes easier to adjust the rotation angle of bolt 54B, which in turn makes it easier to manage the tightening torque of bolt 54B.

[0071] For example, when the driver operates the brake pedal, the master cylinder or the pump increases the pressure in the fluid chamber R. This causes the piston 51 to move forward Df and push the brake pad 12 toward the disc rotor 11.

[0072] When the piston 51 presses the brake pad 12 against the disc rotor 11, the lining 22 of the brake pad 12 comes into contact with the disc rotor 11. For example, the outer wall 42 of the caliper body 31 receives braking torque in the circumferential direction from the back plate 21 of the brake pad 12, causing the disc brake 10 to brake the vehicle.

[0073] For example, vibrations may be input from the brake pads 12 during braking to the piston assembly 32. In this case, the vibrations are input from the piston 51 to the weight 52 and the bolt 54 through the support portion 53.

[0074] At least a portion of the support portion 53, such as the interposed portion 132, has low rigidity and is therefore capable of elastic deformation. Furthermore, the weight 52 and the bolt 54 are spaced apart from the brake pad 12 and the inner surface 64 of the piston 51. Therefore, the weight 52, the bolt 54, and a portion of the support portion 53, such as the mounting portion 131, swing together as a mass M of a mass-spring-damper system. That is, the support portion 53 supports the weight 52 as a spring S of the spring-mass-damper system so that the weight 52 can swing relative to the piston 51. Note that the mounting portion 131 of the support portion 53 swings together with the weight 52 relative to the piston 51 as part of the mass M.

[0075] As described above, the mass M of this embodiment has the weight 52, a part of the support portion 53 such as the mounting portion 131, and the bolt 54. Furthermore, the spring S has a part of the support portion 53 such as the interposition portion 132. However, the entire support portion 53 may be the spring S. Furthermore, the bolt 54 may be omitted from the mass M, and the mass M may have other components.

[0076] The mass M oscillates relative to the piston 51 in accordance with the elastic deformation of the spring S. As a result, the mass M damps vibrations of the brake pad 12 and the piston assembly 32, and can suppress brake squeal at a predetermined frequency.

[0077] During braking, the brake pad 12 becomes hot due to, for example, friction. As a result, heat may be conducted from the brake pad 12 to the piston 51. However, the portion where the piston 51 and the support portion 53 are connected is far from the brake pad 12. Therefore, the piston 51 can reduce heat conduction from the brake pad 12 to the support portion 53 and the weight 52. Therefore, the piston assembly 32 can suppress changes in the spring constant and natural frequency due to frictional heat of the brake pad 12.

[0078] The piston assemblies 32A and 32B have different natural frequencies. This allows the caliper 13 to suppress brake squeal of multiple frequencies. The natural frequency of the piston assembly 32 is set based on the shapes, materials, rigidity, mass, and various other conditions of the piston 51, weight 52, support portion 53, and bolt 54.

[0079] In this embodiment, the weight 52A, support portion 53A, and bolt 54A of the piston assembly 32A and the weight 52B, support portion 53B, and bolt 54B of the piston assembly 32B have different shapes, but other conditions such as materials may also be different.

[0080] In the disc brake 10 according to the first embodiment described above, the piston assembly 32 includes a metal piston 51, a metal weight 52, and a support portion 53. The piston 51 is housed in a cylinder 45, which is provided with an internal space 67. The weight 52 is disposed in the internal space 67. The support portion 53 is formed integrally with the piston 51, has lower rigidity than the piston 51 and the weight 52, and directly supports the weight 52 so that the weight 52 can oscillate relative to the piston 51. Therefore, as an example, the piston assembly 32 allows the weight 52 to oscillate relative to the piston 51 without interposing an elastic body made of a polymer material such as synthetic rubber or synthetic resin between the weight 52 and the piston 51. Furthermore, since the support portion 53 is formed integrally with the piston 51, it is made of metal. Generally, metal has a smaller change in spring constant due to temperature changes than an elastic body made of a polymer material. Therefore, the caliper 13 can damp vibrations by the oscillation of the weight 52 and can suppress changes in the natural frequency of the piston assembly 32 due to temperature. Therefore, the caliper 13 can more reliably suppress brake squeal. Furthermore, because the caliper 13 does not require an elastic body made of a polymer material, the number of parts can be reduced and restrictions on the layout of the weight 52 can be suppressed. Furthermore, because the caliper 13 has an elastically deformable support portion 53 made of metal, durability can be improved.

[0081] For example, in the caliper 13, which is an opposed caliper, the outer diameter of the piston 51 is likely to be set small. However, because the piston assembly 32 does not require an elastic body made of a polymer material, it is possible to place the mass M and spring S having a desired natural frequency in the small internal space 67 of the small-diameter piston 51.

[0082] The piston 51 has an inner surface 64 that defines an interior space 67. The support portion 53 is formed integrally with the piston 51 and protrudes from a bottom surface 66 of the inner surface 64. The weight 52 is attached to the support portion 53. Thus, as an example, the weight 52 can be placed on the support portion 53 that protrudes from the inner surface 64. For example, the weight 52 can be attached to the support portion 53 by a bolt 54. Thus, the caliper 13 can facilitate assembly of the piston assembly 32.

[0083] The support portion 53B has an attachment portion 131 and an intervening portion 132. The attachment portion 131 is attached to the weight 52B and is capable of swinging together with the weight 52B relative to the piston 51. The intervening portion 132 is provided between the attachment portion 131 and the inner surface 64 and is thinner than the attachment portion 131. Therefore, for example, by making the intervening portion 132 thinner, the spring constant can be reduced. Therefore, the caliper 13 can easily set the natural frequency of the piston assembly 32B to a desired value. Furthermore, by making the attachment portion 131 thicker, it can be attached to the weight 52B using, for example, a large bolt 54B. Therefore, the caliper 13 can improve the strength of the connection between the weight 52B and the support portion 53B and easily manage the tightening torque of the bolt 54.

[0084] The caliper 13 has a plurality of piston assemblies 32A, 32B. A plurality of cylinders 45 are provided in the caliper body 31. The plurality of piston assemblies 32A, 32B have different natural frequencies. Therefore, for example, the caliper 13 can suppress brake squeal at a plurality of frequencies.

[0085] In the first embodiment, the support portion 53 is formed integrally with the piston 51. However, the support portion 53 may be formed integrally with the weight 52. In this case, for example, the end of the support portion 53 in the rear direction Db is attached to the piston 51 by screwing, press-fitting, bonding, or other methods.

[0086] (Second embodiment) The second embodiment will be described below with reference to Fig. 3. In the following description of the embodiment, components having the same functions as components already described are given the same reference numerals as the components already described, and further description may be omitted. Furthermore, multiple components given the same reference numerals do not necessarily have all the same functions and properties, and may have different functions and properties according to each embodiment.

[0087] Fig. 3 is a cross-sectional view showing a portion of the caliper 13 according to the second embodiment. As shown in Fig. 3, the piston assembly 32 of the second embodiment has a piston 201 and a dynamic damper 202 instead of the piston 51, the weight 52, the support 53, and the bolt 54. The piston 201 is substantially the same as the piston 51, except for the points described below.

[0088] The piston 201 has an end surface 211 instead of the end surface 61. The end surface 211 is substantially the same as the end surface 61, except that it is spaced apart from the brake pad 12 in the rear direction Db. The end surface 211 may be located inside the cylinder 45.

[0089] The dynamic damper 202 is a metal component. For example, the dynamic damper 202 is made of steel, cast iron, or an aluminum alloy. However, the material of the dynamic damper 202 is not limited to this example. The material of the piston 201 and the material of the dynamic damper 202 may be the same or different.

[0090] The dynamic damper 202 has a weight 221, a lid 222, and a support portion 223. The weight 221, the lid 222, and the support portion 223 are integrally formed. Therefore, the weight 221, the lid 222, and the support portion 223 are metal parts.

[0091] Weight 221 is formed, for example, in a generally cylindrical shape extending along central axis Axc, or in a generally disk shape arranged perpendicular to central axis Axc. Note that the shape of weight 221 is not limited to this example. Weight 221 is arranged in internal space 67 of piston 201. Weight 221 is spaced from inner surface 64 of piston 201. Weight 221 is spaced from end face 211 of piston 201 in rear direction Db.

[0092] The lid 222 is formed in a substantially disk shape and disposed so as to be perpendicular to the central axis Axc. The lid 222 is interposed between the shim 23 of the brake pad 12 and the end face 211 of the piston 201. The lid 222 is supported by the end face 211 and closes the internal space 67. The lid 222 contacts the brake pad 12 and is spaced from the weight 221 in the forward direction Df. Note that the lid 222 may be provided with a through-hole or a notch that communicates with the internal space 67.

[0093] The support portion 223 is formed in a substantially cylindrical shape extending along the central axis Axc. An end of the support portion 223 in the forward direction Df is connected to the lid 222. An end of the support portion 223 in the rearward direction Db is connected to the weight 221. That is, the support portion 223 directly supports the weight 221. The support portion 223 has a smaller diameter than the weight 221 and also has a smaller diameter than the lid 222. The support portion 223 has lower rigidity than both the piston 201 and the weight 221.

[0094] The multiple piston assemblies 32 include multiple piston assemblies 32C and 32D that are different from each other. The piston assembly 32C is one of the multiple piston assemblies 32. The piston assembly 32D is another of the multiple piston assemblies 32. Note that the multiple piston assemblies 32 may be identical to each other.

[0095] The piston 201, the lid 222, and the support portion 223 of the piston assembly 32C are collectively referred to as the piston 201C, the lid 222C, and the support portion 223C. The lid 222C is attached to the end surface 211 of the piston 201C, for example, by adhesive. Note that the lid 222C is not limited to this example. For example, the lid 222C may be sandwiched between the end surface 211 of the piston 201C and the brake pad 12.

[0096] The piston 201, the lid 222, and the support portion 223 of the piston assembly 32D are collectively referred to as a piston 201D, a lid 222D, and a support portion 223D. The piston 201D has a female thread 231. The female thread 231 is provided on an inner circumferential surface 65 of the piston 201D.

[0097] The lid 222D has a fitting portion 241, a flange 242, and a male thread 243. The fitting portion 241 fits into the internal space 67. The flange 242 is connected to the fitting portion 241 and is supported by the end surface 211 of the piston 201D. The male thread 243 is provided on the fitting portion 241 and fits with the female thread 231 of the piston 201D. In this way, the lid 222D is attached to the piston 201D.

[0098] The fitting portion 241 is spaced apart from the brake pad 12. For this reason, the cover 222D is provided with a recess 245. The recess 245 is defined by the fitting portion 241 and the flange 242, for example.

[0099] Support portion 223D is thinner than support portion 223C. Therefore, support portion 223D has lower rigidity than support portion 223C. Support portion 223D is solid, but may be hollow. That is, support portion 223D may be provided with a hole that communicates with recess 245.

[0100] The support portion 223 has low rigidity and is therefore capable of elastic deformation. Furthermore, the weight 221 is spaced apart from the brake pad 12 and the inner surface 64 of the piston 201. Therefore, for example, during braking, the weight 221 oscillates as a mass M. That is, the support portion 223 supports the weight 221 as a spring S so that the weight 221 can oscillate relative to the piston 201. The mass M oscillates relative to the piston 201 in accordance with the elastic deformation of the spring S. As a result, the mass M damps vibrations of the brake pad 12 and the piston assembly 32, and brake squeal at a predetermined frequency can be suppressed.

[0101] The fitting portion 241 of the lid 222D is spaced apart from the brake pad 12. Therefore, the lid 222D can reduce heat conduction from the brake pad 12 to the support portion 223D and the weight 221. Therefore, the piston assembly 32D can suppress changes in the spring constant and natural frequency due to frictional heat of the brake pad 12.

[0102] Piston assembly 32C and piston assembly 32D have different natural frequencies. Therefore, caliper 13 can suppress brake squeal of multiple frequencies. Note that caliper 13 may include at least one of piston assemblies 32A and 32B and at least one of piston assemblies 32C and 32D.

[0103] In the disc brake 10 of the second embodiment described above, the internal space 67 is open to the outside of the piston 201. The piston assembly 32 has a lid 222 that closes the internal space 67. The support portion 223 is formed integrally with the weight 221 and the lid 222. Therefore, for example, the piston 201 can simplify the shape of the internal space 67, making it easier to manufacture.

[0104] In the above embodiment, the support portion 53 is formed integrally with the piston 51, and the support portion 223 is formed integrally with the weight 221. However, the support portion may be formed integrally with both the weight and the piston. For example, a support portion formed integrally with both the weight and the piston may be formed by cutting or 3D printing.

[0105] At least one of the calipers described above includes, for example, a caliper body having at least one cylinder; a metal piston housed in the cylinder and having an internal space; a metal weight disposed in the internal space; and a support portion integrally formed with at least one of the piston and the weight, having lower rigidity than the piston and the weight, and directly supporting the weight so that the weight can oscillate relative to the piston. Thus, for example, the piston assembly allows the weight to oscillate relative to the piston without an elastic body made of a polymer material such as synthetic rubber or synthetic resin interposed between the weight and the piston. Furthermore, since the support portion is integrally formed with at least one of the piston and the weight, it is made of metal. Generally, metal has a smaller change in spring constant due to temperature changes than an elastic body made of a polymer material. Therefore, the caliper can damp vibrations by the oscillation of the weight and can suppress temperature-related changes in the natural frequency of the piston assembly. Therefore, the caliper can more reliably suppress brake squeal. Furthermore, since the caliper does not require an elastic body made of a polymer material, the number of parts can be reduced and limitations on the layout of the weight can be suppressed.Furthermore, since the support part that elastically deforms is made of metal, the durability of the caliper can be improved.

[0106] In the caliper, for example, the piston has an inner surface that defines the internal space, the support portion is integrally formed with the piston and protrudes from the inner surface, and the weight is attached to the support portion. Thus, for example, the weight can be placed on the support portion that protrudes from the inner surface. For example, the weight can be attached to the support portion directly or by a screw. Therefore, the caliper can facilitate assembly of the piston assembly.

[0107] In the above caliper, as an example, the support portion includes an attachment portion attached to the weight and capable of swinging relative to the piston together with the weight, and an intervening portion provided between the attachment portion and the inner surface and thinner than the attachment portion. Therefore, as an example, by designing the intervening portion to be thin, the spring constant can be reduced. Therefore, the caliper's natural frequency can be easily set to a desired value. Furthermore, by designing the attachment portion to be thick, it can be attached to the weight using, for example, a large screw. Therefore, the caliper can improve the strength of the connection between the weight and the support portion and facilitate management of the tightening torque of the screw.

[0108] In the caliper, for example, the internal space is open to the outside of the piston, the piston assembly has a lid that closes the internal space, and the support portion is formed integrally with the weight and the lid. Thus, for example, the shape of the internal space of the piston can be simplified, making it easier to manufacture.

[0109] For example, the caliper includes a plurality of the piston assemblies, the plurality of cylinders are provided in the caliper body, and the plurality of piston assemblies have different natural frequencies, so that the caliper can suppress brake squeal at a plurality of frequencies.

[0110] While the embodiments of the present invention have been described above, the above-described embodiments and modifications are merely examples and are not intended to limit the scope of the invention. The above-described embodiments and modifications can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the configurations and shapes of each embodiment and each modification can be partially interchanged. [Explanation of symbols]

[0111] 13... caliper, 31... caliper body, 32, 32A, 32B, 32C, 32D... piston assembly, 45... cylinder, 51, 201, 201C, 201D... piston, 52, 52A, 52B, 221... weight, 53, 53A, 53B, 223, 223C, 223D... support portion, 67... internal space, 131... mounting portion, 132... interposition portion, 222, 222C, 222D... lid.

Claims

1. a caliper body provided with at least one cylinder; at least one piston assembly including: a metal piston accommodated in the cylinder and having an internal space; a metal weight disposed in the internal space; and a support portion formed integrally with at least one of the piston and the weight, having lower rigidity than the piston and the weight, and directly supporting the weight so that the weight can swing relative to the piston; A caliper comprising:

2. the piston has an inner surface that defines the interior space; the support portion is integrally formed with the piston and protrudes from the inner surface; The weight is attached to the support. The caliper of claim 1.

3. The support portion includes a mounting portion attached to the weight and swingable together with the weight with respect to the piston, and an interposition portion provided between the mounting portion and the inner surface and thinner than the mounting portion. The caliper of claim 2.

4. The internal space is open to the outside of the piston, The piston assembly has a lid that closes the internal space, The support portion is formed integrally with the weight and the lid. The caliper of claim 1.

5. a plurality of said piston assemblies; Equipped with The caliper body is provided with a plurality of the cylinders, The plurality of piston assemblies have different natural frequencies. A caliper according to any one of claims 1 to 4.

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