JP4608390B2 - Vehicle disc brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a structure of inhibiting one of a nut and a screw shaft from turning and enhance assembling characteristics, in a disk brake for a vehicle in which the screw shaft coaxial to a brake piston and the nut screwed with the screw shaft are arranged on a back side of the brake piston slidably and non-rotatively fitted to a caliper body and one of the screw shaft and nut is inhibited from turning. <P>SOLUTION: A fitting section 38a with an equilateral polygon on its outer periphery is arranged on either of the screw shaft 37 and nut 38, and locking grooves 43 having integer times of the number of a plurality of edge sections 42 having connecting sections 38a are arranged on an inner periphery of the cylindrical brake piston 29 with a bottom in a circumferential direction in regular intervals while extending in an axial direction so that the edge sections 42 are selectively connected with each other at numerous locations where their phases are selectively shifted each other in a circumferential direction. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  In the present invention, a screw shaft coaxial with the brake piston and a nut screwed to the screw shaft are disposed behind the brake piston that is slidably and non-rotatably fitted to the caliper body, and the screw shaft The present invention also relates to a vehicle disc brake in which one of the nuts cannot be rotated.

In order to automatically adjust the amount of wear of the friction pad, a vehicle disc brake in which an automatic adjustment mechanism including a screw shaft and a nut screwed to the screw shaft is disposed behind a brake piston is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-122867. And already known from US Pat.
Japanese Patent Laid-Open No. 10-73137 JP 2004-28304 A

  Incidentally, one of the screw shaft and the nut is made non-rotatable. However, in Patent Document 1 and Patent Document 2, the structure for making one of the screw shaft and the nut non-rotatable is complicated, and the assemblability is improved. There is also a problem.

  The present invention has been made in view of such circumstances, and provides a vehicle disc brake that simplifies the structure for making one of the screw shaft and the nut unrotatable and improves assembly. Objective.

In order to achieve the above object, according to the first aspect of the present invention, a brake piston, which is formed in a bottomed cylindrical shape with an open rear end in a cylinder hole provided in a caliper body and can press a friction pad at the front end, is slidable. And a screw mechanism capable of transmitting the output of the electric motor to the brake piston is provided between the brake piston and the electric motor attached to the caliper body. and the screw shaft of the brake piston coaxially disposed behind the brake piston provided with a nut screwed on the screw shaft, the screw shaft and one vehicle disc brake and unrotatable of the nut in, wherein the said cylinder bore on the rear side of the brake piston, together with the liquid pressure chamber in which the screw mechanism faces is defined, guide the fluid pressure in the hydraulic chamber Provided hydraulic passage within the caliper body, while the engaging portion is regular polygon in cross-section is provided with outer periphery of the screw shaft and the nut, the inner periphery of the front Symbol brake piston, wherein the engagement Locking grooves that are integral multiples of the number of corners of the part are provided at equal intervals in the circumferential direction while extending in the axial direction, and the corners are selectively engaged with the locking grooves, The locking groove not engaged with the corner portion is an air vent groove .

According to a second aspect of the present invention, in addition to the feature of the first aspect of the invention, the inner periphery of the brake piston has a shape in which a plurality of regular polygons whose phases are shifted from each other when viewed in cross section are overlapped. It is formed.

According to the onset bright, on the inner periphery of the locking groove of the brake piston can not rotate, only engage the corners of the engagement portion provided on one of the screw shaft and the nut to the outer periphery as a regular polygon of One of the screw shaft and the nut can be made non-rotatable with a simple structure. In addition, a locking groove that is an integral multiple of the number of the plurality of corner portions of the engaging portion is provided on the inner periphery of the brake piston, and each locking groove has a corner portion at a plurality of locations that are out of phase in the circumferential direction. Since they are arranged at equal intervals in the circumferential direction while extending in the axial direction so as to be selectively engaged, alignment when engaging the engaging portion with the brake piston is easy, and the assembling property can be improved. . Further, the air bleeding performance is enhanced by the locking groove in which the engaging portion is not locked.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 12 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a vehicle disc brake, taken along line 1-1 in FIG. 2, and FIG. 2 is a cross-sectional view taken along line 3-3 in FIG. 1, FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 1, and FIG. 5 is a sectional view taken along line 5-5 in FIG. 6 is a view of the brush holder as viewed from the direction of arrows 6-6 in FIG. 1, FIG. 7 is a view of the brush holder as viewed from the directions of arrows 7-7 in FIG. 1, and FIG. FIG. 9 is a sectional view taken along the line 9-9 in FIG. 5, and FIG. 10 is a sectional view taken along the line 10-10 in FIG. FIG. 11 is an enlarged view of the main part of FIG. 1, and FIG. 12 is a side view of the vehicle with the disc brake mounted on the rear wheel.

  First, in FIG. 1 and FIG. 2, this vehicle disc brake can obtain a service brake state by hydraulic pressure and can be operated by an electric motor 34 to obtain a parking brake state. A disk rotor 15 that rotates with a wheel of a wheel (not shown), a caliper body 16, and a pair of friction pads 17, 18 that are disposed opposite to both side surfaces of the disk rotor 15 and are disposed between the disk rotor 15 and the caliper body 16. With.

  The caliper body 16 is supported by a bracket 19 attached to the vehicle body so as to be slidable in a direction along the axis of the disk rotor 15, and extends from the housing part 16 a to the opposite side across the disk rotor 15. Arm portion 16b.

A friction pad 17 having an axis parallel to the axis of the disk rotor 15 and having a bottomed cylindrical shape and facing one side of the disk rotor 15 on the housing portion 16a side slides on the disk rotor 15 to generate a frictional force. A lining 22 capable of exhibiting friction is provided on the back metal 20, and the friction pad 18 facing the other side of the disk rotor 15 on the arm portion 16b side is in sliding contact with the disk rotor 15 to provide a lining 23 capable of exhibiting frictional force. The two friction pads 17 and 18 are held by the bracket 19 so as to be movable in the direction along the axis of the disk rotor 15.

  The caliper body 16 has a housing portion 16 a which has a cylinder hole 24 having an axis parallel to the axis of the disk rotor 15 and opened to the friction pad 17, and an accommodation recess opened to the opposite side of the friction pad 17. 25 and a partition wall 26 interposed between the cylinder hole 24 and the accommodating recess 25. The cylinder hole 24 and the accommodating recess 25 are formed so as to have a circular cross section on the same axis, and a through hole 27 that coaxially connects the cylinder hole 24 and the accommodating recess 25 is provided at the center of the partition wall 26. .

  In the cylinder hole 24, a hydraulic chamber 28 is formed between the partition wall 26 and a bottomed cylindrical brake piston 29 with the front end closed so that the front end abuts against the back metal 20 of the friction pad 17. The front end of the brake piston 29 is engaged with the back metal 20 to prevent rotation in the cylinder hole 24.

  An annular piston seal 30 interposed between the caliper body 16 and the brake piston 29 is mounted on the inner surface of the cylinder hole 24, and an annular dust boot 31 is provided between the opening end of the cylinder hole 24 and the brake piston 29. The housing portion 16a is provided with a fluid pressure path 32 that guides fluid pressure to the fluid pressure chamber 28.

  By the way, to the brake piston 29, the output of the electric motor 34 that exerts the power to move the friction pads 17 and 18 forward and backward with respect to the disk rotor 15 is transmitted via the speed reduction mechanism 35 and the screw mechanism 36 that decelerates the output. The screw mechanism 36 is accommodated in the housing portion 16a of the caliper body 16 so as to be disposed behind the brake piston 29, and the speed reduction mechanism 35 is supported by the electric motor 34 and accommodated in the accommodating recess 25. The electric motor 34 is attached to the housing portion 16 a of the caliper body 16 on the side opposite to the disk rotor 15.

  The screw mechanism 36 includes a screw shaft 37 that is coaxial with the cylinder hole 24, and a nut 38 that is engaged with the brake piston 29 and cannot be relatively rotated, and is screwed into the screw shaft 37. On the opposite side, at the rear end of the screw shaft 37, a connecting shaft portion 37a that rotatably passes through the through hole 27 of the partition wall 26 is coaxially and integrally connected, and a flange portion 37b that projects radially outward is provided. Provided integrally. Thus, an O-ring 39 is interposed between the partition wall 26 and the connecting shaft portion 37a of the housing portion 16a, and a thrust bearing 40 is interposed between the flange portion 37b and the partition wall 26. A retaining ring 41 that is in contact with the surface of the partition wall 26 on the housing recess 25 side is mounted on the outer periphery of the 25-side protrusion.

  3 and 4 together, the screw shaft 37 is screwed into a nut 38 surrounding the screw shaft 37 in the brake piston 29. The nut 38 has an engaging portion 38a having a regular polygonal outer periphery, in this embodiment, an engaging portion 38a having a regular rectangular outer periphery, and the front end surface of the engaging portion 38a is the brake piston 29. Abuts against the inner surface of the front end.

  On the other hand, on the inner periphery of the brake piston 29 having a bottomed cylindrical shape, an integral multiple (two in this embodiment) of the number of corner portions 42... (Four in this embodiment) of the engaging portion 38a. Are provided at equal intervals in the circumferential direction while extending in the axial direction so as to selectively engage the corner portions 42 at a plurality of locations shifted in phase in the circumferential direction. That is, the inner periphery of the brake piston 29 corresponds to the outer peripheral shape of the engaging portion 38a and is formed in a shape in which a plurality of regular polygons whose phases are shifted from each other are overlapped. In this embodiment, the phase is 45. It is formed in a star shape with two regular squares that are offset.

  As clearly shown in FIG. 1, a disc spring 44 that biases the nut 38 in the forward direction is provided between the flange portion 37 b of the screw shaft 37 and the nut 38.

  In such a screw mechanism 36, when the power from the electric motor 34 is decelerated by the speed reduction mechanism 35 and the power that rotates in one direction is transmitted to the screw shaft 37, the rotation of the brake piston 29 and the nut 38 is prevented. In this state, the disc rotor 15 is clamped from both sides by the friction pads 17 and 18 due to the action and the reaction caused by the brake piston 29 sliding forward in the axial direction, whereby a braking force is obtained. Further, when the screw shaft 37 is rotated in the other direction, the brake piston 29 slides rearward in the axial direction to release the braking state.

  Referring also to FIG. 5, the electric motor 34 is provided with a motor housing 46 attached to the housing portion 16 a of the caliper body 16, and an armature 49 that is rotatably supported by the motor housing 46 and has a commutator 50. An output shaft 47 and a brush holder 48 fixed to the motor housing 46 are provided and can be rotated forward and backward.

  The motor housing 46 includes a bottomed cylindrical yoke 51 that coaxially surrounds the armature 49 and a lid plate 52 that sandwiches the brush holder 48 between the open end of the yoke 51. A plurality of magnets 63, 63... Are fixed to the inner periphery of the yoke 51 at a portion corresponding to the armature 49.

  A cylindrical bearing housing 51 a is integrally provided on the inner surface of the closed end central portion of the yoke 51 having a bottomed cylindrical shape, and one end portion of the output shaft 47 is connected to the bearing housing via a first motor bearing 53. 51a is rotatably supported. A flange 51b that projects outward in the radial direction is integrally provided at the opening end of the yoke 51.

  Referring also to FIG. 6, the brush holder 48 surrounds the output shaft 47 at a portion substantially corresponding to the commutator 50, and is formed in a ring shape by, for example, a synthetic resin, and the flange portion 51 b of the yoke 51. A plurality of, for example, four brushes 54, 54... That are in sliding contact with the commutator 50 are held by the brush holder 48. In addition, the brushes 54, 54... Are urged toward the side in sliding contact with the commutator 50 by springs 55, 55.

  The lid plate 52 is formed in a ring plate shape with the brush holder 48 sandwiched between the flange portion 51b, and the other end side of the output shaft 47 passes through the central portion of the lid plate 52 to freely rotate and decelerate. Projects to the mechanism 35 side. In addition, a cylindrical bearing housing 52a is integrally provided at the center of the lid plate 52, and a portion corresponding to the lid plate 52 of the output shaft 47 is sealed via a second motor bearing 56. The bearing housing 52a is rotatably supported.

  The rotation angle of the electric motor 34 is detected by a rotation angle detection sensor 57 housed and arranged in the motor housing 46, and the pulser 58 to be detected by the rotation angle detection sensor 57 is the motor housing 46. In the output shaft 47. Moreover, the pulsar 58 is provided on the output shaft 47 between the commutator 50 and the second motor bearing 56 provided between the output shaft 47 and the cover plate 52 of the motor housing 46 outside the commutator 50. ing.

  Referring also to FIG. 7, a recess 59 that is opened to the inner periphery of the brush holder 48 at a portion corresponding to the pulsar 58 and is covered with the cover plate 52 is provided in the brush holder 48. It is accommodated and fixed in the recess 59. Moreover, the rotation angle detection sensor 57 is accommodated in the resin case 62 together with the magnet 60 and the capacitor 61, and the resin case 62 is accommodated and fixed in the recess 59 by adhesion or the like.

  Referring also to FIG. 8, at a plurality of positions spaced apart in the circumferential direction of the brush holder 48, in this embodiment, at three positions, the elastic engagement mechanism capable of elastically engaging with the flange portion 51 b of the yoke 51. Joint portions 66, 66, 66 are projected, and the bullet engaging portions 66... Are at least one bullet engaging portion 66 of each of the bullet engaging portions 66. The protrusions of the brush holder 48 are spaced apart in the circumferential direction so that the interval between the remaining elastic engagement portions 66 adjacent to the other elastic release engagement portions 66 differs from the mutual interval. Established. Thus, in this embodiment, since the three elastic engagement portions 66 are projected from the brush holder 48, the angular intervals α, β, γ of the respective elastic engagement portions 66 are different from each other. For example, α is 120 degrees, β is 130 degrees, and γ is 110 degrees.

  Moreover, the bullet engaging portion 66 is formed by a pair of engaging claws 66 a and 66 a being arranged to face each other, and each of the bullet engaging portions 66... Is an engagement hole provided in the flange 51 b of the yoke 51. 67 are respectively inserted into and elastically engaged with the flange 51b.

  By the way, the speed reduction mechanism 35 is accommodated in a case 70 that includes a cover plate 52 that constitutes a part of the motor housing 46 as one component, and the case 70 is elastically engaged with the case 70. A plurality of bullet engaging portions 71, 71, 71 that can be temporarily fixed to the electric motor 34 side are projected from the brush holder 48.

  The bullet engaging portion 71 is composed of a pair of engaging claws 71a, 71a facing each other, and each of the bullet engaging portions 71... The brush holder 48 protrudes at an interval.

  Thus, the brush holder 48 is temporarily fixed to the yoke 51 by the elastic engagement portions 66... And the case 70 is temporarily fixed to the brush holder 48 by the elastic engagement portions 71. It is possible to temporarily fix the motor housing 46, the brush holder 48, and the case 70 through the intermediate member. The motor housing 46, the brush holder 48, and the case 70 in the temporarily fixed state are commonly attached to the housing portion 16a of the caliper body 16 by a plurality of, for example, three attachment bolts 72, and the brush holder 48. Are embedded with metal cylindrical sleeves 73 through which the mounting bolts 72 are inserted.

  The brush holder 48 is integrally provided with a coupler 48a that protrudes laterally from the outer periphery of the motor housing 46. In the coupler 48a, connection terminals 74 that are respectively connected to the brushes 64 are connected. A connection terminal 75 and the like connected to the rotation angle detection sensor 57 are disposed. Thus, it is possible to connect the external connector 64 which is a female type to the male coupler 48a so as to be detachable.

  The brush holder 48 constituting a part of the motor housing 46 is provided with a bottomed cylindrical motor cover 78 having an annular seal member 77 interposed between the brush holder 48 and the caliper body 16 of the motor housing 46. Are attached so as to cover at least the metal yoke 51 and the mounting bolts 72.

  In addition, the motor cover 78 is bayonet-coupled to the brush holder 48 provided with a coupler 48a for removably fitting and connecting the external connector 64 to the side.

  That is, engagement projections 79 are projected at a plurality of, for example, two locations at equal intervals in the circumferential direction of the inner surface of the opening end of the motor cover 78, and the engagement projections 79 are projected on the outer periphery of the brush holder 48. Are provided with engaging recesses 80.

  In FIG. 9, the engagement recess 80 provided on the outer periphery of the brush holder 48 is axially arranged so that the engagement protrusion 79 is inserted and removed by displacing the motor cover 78 in the axial direction with respect to the brush holder 48. And a groove portion 80a having an outer end opened to the opposite side of the caliper body 16 and a groove portion 80b having one end connected at a right angle to the inner end of the groove portion 80a and extending along the circumferential direction of the brush holder 48. It is formed in a letter shape.

  Thus, by operating the motor cover 78 so that the engaging projection 79 inserted into the groove 80a is displaced to the other end side of the groove 80b, the motor cover 78 is bayonet-coupled to the brush holder 48 of the motor housing 46. It will be.

  The motor cover 78 is integrally provided with an engaging portion 81 that protrudes outward. The engaging portion 81 is fitted and connected to the coupler 48a of the brush holder 48 as shown in FIG. The motor cover 78 is engaged with the external connector 64 in a state where the motor cover 78 is coupled to the brush holder 48.

  In addition, the engaging portion 81 is provided on the motor cover 78 so that when the bayonet coupling of the motor cover 78 to the motor housing 46 is incomplete, the external connector 64 cannot be fitted into the coupler 48a. Yes.

  In FIG. 11, the speed reduction mechanism 35 is a wave gear mechanism, and includes a wave generator 84 in which a ball bearing 86 is mounted on the outer periphery of an elliptical cam 85 that is coaxially connected to the output shaft 47 of the electric motor 34, and an outer periphery. A plurality of teeth 88 are provided on the outer ring of the ball bearing 86. The flexspline 87 forms a part of the case 70 and is fixed to the caliper body 16 and one half of the flexspline 87. Output-side circular spline 89 having teeth 90 meshing with the teeth 88 of the inner part and teeth 92 meshing with teeth 88 of the other half of the flexspline 87 on the inner periphery. The spline 91 and an output rotating member 93 coupled to the output-side circular spline 91 are housed in the case 70. Moreover, the number of teeth 90 on the inner circumference 90 of the fixed-side circular spline 89 is the same as the number of teeth 88 on the outer circumference of the flexspline 87, and the number of teeth on the inner circumference 92 of the output-side circular spline 91 is as follows. Two more than the number of teeth 88 on the outer periphery of the flexspline 87 are set.

  The case 70 includes a lid plate 52 that constitutes a part of the motor housing 46, a fixed-side circular spline 89 that contacts the lid plate 52, and the fixed-side circular spline 89 sandwiched between the lid plate 52. A mounting bolt for attaching the motor housing 46 of the electric motor 34 to the caliper body 16 is configured with a case member 94 having a flange 94a projecting radially outward from the opening end and formed in a cup shape. 72 to the caliper body 16. Moreover, annular seal members 95 and 96 are interposed between the cover plate 52 and the fixed-side circular spline 89, and between the fixed-side circular spline 89 and the flange portion 94a of the case member 94, respectively.

  The other end of the output shaft 47 that is rotatably supported by a second motor bearing 56 with a seal on the bearing housing 52 a in the center of the cover plate 52 is inserted into the case 70, and an elliptical cam 85 in the wave generator 84. The wave generator 84 is coaxially connected to the output shaft 47 by being coaxially fitted to the central portion thereof so as not to be relatively rotatable.

  The output rotating member 93 includes a ring plate portion 93a fastened to the output-side circular spline 91 by a plurality of bolts 97, and a cylindrical portion 93b protruding from the inner periphery of the ring plate portion 93a to the side opposite to the wave generator 84. An end wall portion 93c that closes the base end of the cylindrical portion 93b so that a concave portion 98 that faces the wave generator 84 is formed in cooperation with the inner periphery of the ring plate portion 93a, and the end wall portion 93c. A shaft portion 93d that protrudes from the center portion of the case member 94 to the opposite side of the wave generator 84 is integrally provided, and a circular opening portion 99 that coaxially arranges the cylindrical portion 93b is formed in the center portion of the case member 94. Provided.

  A ball bearing 100 with a seal is interposed between the inner periphery of the opening 99 in the case member 94 and the cylindrical portion 93 b of the output rotating member 93. Thus, the inside of the case 70 includes the ball bearing 100, the fixed-side circular spline 89, the sealing members 95 and 96 interposed between the lid plate 52 and the flange portion 94 a of the case member 94, and the center of the lid plate 52. And the sealed second motor bearing 56 interposed between the output shaft 47 and the output shaft 47, and the grease 101 is filled in the case 70.

  The shaft portion 93d of the output rotating member 93 is liquid-tightly projected from the case 70, and this shaft portion 93d is fitted coaxially to the connecting shaft portion 37a of the screw shaft 37 of the screw mechanism 36 so as not to be relatively rotatable. Combined. That is, the output shaft 47 of the electric motor 34 is coaxially fitted and connected to an elliptical cam 85 that is an input member of the speed reduction mechanism 35 so as not to rotate relative thereto, and the output rotation member 93 of the speed reduction mechanism 35 is coaxial with the output shaft 47. The screw shaft 37 is fitted and connected so as not to be relatively rotatable.

  By the way, when the speed reduction mechanism 35 is accommodated in the case 70, the structure of the speed reduction mechanism 35 is used in order to absorb and reliably accommodate a plurality of parts constituting the speed reduction mechanism 35 and dimensional errors and assembly errors of the case 70. It is desirable that at least one of the components is allowed to move in the axial direction within the case 70 within a limited range, and the axial movement within the case 70 within the limited range of the output rotation member 93 is desirable. However, between the ball bearing 100 in a fixed position with respect to the case 70 and the disk portion 93a of the output rotating member 93, the output rotating member 93 is axially arranged in one direction (in this embodiment, the ball bearing). 98) is provided.

  The other end of the output shaft 47 protruding from the elliptical cam 85 is coaxially inserted into the recess 98 of the output rotating member 93, and between the other end outer periphery of the output shaft and the inner periphery of the recess 93. Is provided with a ball bearing 103. Thus, the elliptical cam 85 of the wave generator 84 is coaxially fitted and connected to the output shaft 47, and the flex spline 87 is mounted on the outer periphery of the wave generator 84, and the outputs are fastened to each other by bolts 97. Since the side circular spline 91 and the output rotating member 93 are supported by the output shaft 47 via the ball bearing 103, a plurality of components constituting the speed reduction mechanism 35 at the other end portion of the output shaft 47 that enters the case 70. Among the elements, the wave generator 84, the flex spline 87, the output side circular spline 91 and the output rotating member 93, which are components that rotate, are coaxially supported.

  By the way, the accommodation recess 25 provided in the housing part 16a of the caliper body 16 has an inner diameter for fitting a part of the case member 94 in the case 70 of the speed reduction mechanism 35 and one end thereof closed by the partition wall 26. The medium diameter portion 25b is configured such that the medium diameter portion 25b having a diameter larger than that of the small diameter portion 25a and having one end connected to the other end of the small diameter portion 25a via a step and the flange portion 94a of the case member 94 are brought into contact with each other. An annular step portion 25c connected to the other end of the housing, and a large-diameter portion 25d having one end connected to the outer periphery of the annular step portion 25c and the other end opened to the end surface of the housing portion 16a on the electric motor 34 side. The large-diameter portion 25d is fitted with a fitting cylinder portion 48b provided integrally with a brush holder 48 constituting a part of the motor housing 46 in the electric motor 34. It is.

  Thus, when the motor housing 46 of the electric motor 34 is attached to the housing main portion 16 a of the caliper body 16, the shaft portion 93 d of the output rotating member 93 in the reduction mechanism 35 is coaxial with the rear end of the screw shaft 37 in the screw mechanism 36. And a part of the case member 94 in the case 70 of the speed reduction mechanism 35 is fitted into the small-diameter portion 25a of the housing recess 25, and the fitting tube portion 48b of the brush holder 48 in the motor housing 46 is fitted into the housing recess. The fitting length of the shaft portion 93d of the output rotation member 93 to the screw shaft 37 is set to fit into a part of the housing recess 25. The total length and the fitting length of the fitting cylindrical portion 48b of the brush holder 48 into the receiving recess 25 are set. That is, when the motor housing 46 of the electric motor 34 in a state where the case 70 of the speed reduction mechanism 35 is temporarily fixed is assembled to the housing main portion 16 a, the shaft portion 93 d of the output rotation member 93 is a part of the housing recess 94. Fitting to the screw shaft 37 is started prior to fitting to 25 and fitting of the fitting cylindrical portion 48b of the brush holder 48 to the receiving recess 25.

  An annular seal member 104 surrounding the case 70 of the speed reduction mechanism 35 is interposed between the housing main portion 16 a in the caliper body 16 and the brush holder 48 in the motor housing 46 of the electric motor 34. Further, the annular step 25c of the housing recess 25 in the housing main portion 16a is provided with recesses 105 for housing the tips of a plurality of fitting projections 71 for temporarily fixing the case 70 to the motor housing 46.

  As shown in FIG. 12, such a disc brake is mounted on the rear wheel WR of the vehicle. When the disc brake is mounted on the rear wheel WR, the coupler 48a is positioned in the horizontal direction relative to the rotation center C of the rear wheel WR. It is disposed on the rear side along the front-rear direction of the vehicle, and the opening of the coupler 48a is disposed so as to be directed obliquely downward on the rear side.

  Next, the operation of this embodiment will be described. Behind the brake piston 29 slidably and non-rotatably fitted to the housing main portion 16a of the caliper body 16, a screw shaft 37 coaxial with the brake piston 29 and A nut 38 that is screwed onto the screw shaft 37 is provided, and the nut 38 is engaged with the brake piston 29 in a non-rotatable manner. Is provided with an engaging portion 38a having a bottomed cylindrical shape, and an engaging groove that is an integral multiple of the number of the plurality of corner portions 42 of the engaging portion 38a on the inner periphery of the brake piston 29 having a bottomed cylindrical shape. 43 are provided at equal intervals in the circumferential direction while extending in the axial direction so as to selectively engage the corners 42 at a plurality of positions shifted in phase in the circumferential direction.

  Accordingly, the engaging groove 43 on the inner periphery of the brake piston 29, which cannot be rotated, has a simple structure in which each corner portion 42 of the engaging portion 38a provided on the nut 38 has a regular polygonal outer periphery. The nut 38 can be made non-rotatable. In addition, the engaging grooves 38 are provided on the inner circumference of the brake piston 29 by an integral multiple of the number of the plurality of corners 42 included in the engaging portion 38 a, and when the engaging portion 38 a is engaged with the brake piston 29. Can be easily aligned, and the assemblability can be improved. Further, the air release performance is enhanced by the locking grooves 43... In which the engaging portions 38 a are not locked.

  A disc spring 44 is provided between the nut 38 and the screw shaft 37 to urge the nut 38 in the forward direction. When the brake piston 29 returns, the nut 38 and the screw shaft 39 are screwed together. An excessively large tightening force can be prevented by the action of the disc spring 44, and an unnecessary load is not applied during reactivation.

  In addition, the motor housing 46 of the electric motor 34 that exhibits the power for driving the brake piston 29 in the axial direction has a metal yoke 51 that constitutes a part of the motor housing 46 disposed outside the caliper body 16. The motor housing 46 is attached to the body 16 with a plurality of mounting bolts 72..., And the motor cover 78 with a seal member 77 interposed between the motor housing 46 and the motor housing 46 includes at least the yoke 51 and the mounting bolt 72. Are attached so as to cover the yoke 51 and the mounting bolts 72 are made of a corrosion-resistant material, and the yoke 51 and the mounting bolts 72 are rusted while avoiding an increase in cost. Can be prevented.

  The motor cover 78 is bayonet-coupled to a motor housing 46 having a brush holder 48 provided so that a coupler 48a for removably fitting and connecting the external connector 64 protrudes laterally. An engaging portion 81 that can be engaged with the external connector 64 fitted and connected to the coupler 48 a in a bayonet-coupled state of the motor cover 78 to the motor housing 46 is integrally provided. That is, in a state where the motor cover 78 is bayonet-coupled to the motor housing 46, the engaging portion 81 of the motor cover 78 can be engaged with the external connector 64 that is fitted and connected to the coupler 48a of the motor housing 46. The structure for stopping the rotation of the motor cover 78 can be simplified.

  In addition, the engaging portion 81 is provided on the motor cover 78 so that when the bayonet coupling of the motor cover 78 to the motor housing 46 is incomplete, the external connector 64 cannot be fitted to the coupler 48a. Depending on whether or not the external connector 64 can be fitted to the coupler 48a, it is possible to identify complete or incomplete connection of the bayonet to the motor housing 46 of the motor cover 78, and to prevent erroneous assembly.

  Further, a plurality of bullet engaging portions 66 that can be elastically engaged with the yoke 51 are adjacent to at least one of the bullet engaging portions 66 and the bullet engaging portion 66. The brush holder 48 protrudes in the circumferential direction so as to be spaced apart from other elastic engagement portions 66 that are different from the intervals between the remaining elastic engagement portions 66. Therefore, the circumferential relative positions of the yoke 51 and the brush holder 48 are fixed and are held by the brush holder 48 in a state where the elastic engagement portions 66 provided in the brush holder 48 are elastically engaged with the yoke 51. Since the relative positions of the brushes 54 and the magnets 63 fixed to the inner periphery of the yoke 51 are also fixed, the assembling work is performed so that the relative positions of the brush holder 48 and the yoke 51 can be easily and uniformly determined. To increase efficiency. It can be the output characteristic of the electric motor 34 and that of the setting manner.

  The electric motor 34 is linked and connected to the rear portion of the screw shaft 37 via the speed reduction mechanism 35, but the output shaft 47 of the electric motor 34 is fitted and connected to the wave generator 84 of the speed reduction mechanism 35 so as not to be relatively rotatable. Since the output rotation member 93 of the speed reduction mechanism 35 is coaxially connected to the output shaft 47 and is connected to the screw shaft 37 so as not to rotate relative thereto, the output rotation member 93 is connected to the screw mechanism 36 connected to the brake piston 29 via the speed reduction mechanism 35. Thus, the assembling work when assembling the electric motor 34 to be connected is simplified, and the assembling workability can be improved.

In addition, the electric motor 34 includes a motor housing 46 attached to the caliper body 16, an output shaft 47 that is rotatably supported by the motor housing 46, and a brush that is in sliding contact with a commutator 50 included in an armature 49 provided on the output shaft 47. 54, and a brush holder 48 fixed to the motor housing 46. The brush holder 48 projects a part of the output rotating member 93 so as to be detachable and removably attached to the case 70 housing the speed reduction mechanism 35. Since a plurality of elastic engagement portions 71 ... That engage and temporarily fix the case 70 to the electric motor 34 side are projected, the electric motor 34 is calipered with the speed reduction mechanism 35 temporarily fixed. Since it can assemble | attach to the body 16 side, an assembly workability | operativity can be improved more.

  In addition, the electric motor 34 in a state in which the case 70 is temporarily fixed can be assembled to the caliper body 16 while fitting the brush holder 48 and the case member 94, which are other members than the output rotating member 93, to the caliper body 16. Yes, the fitting length of the output rotating member 93 of the speed reduction mechanism 35 to the screw shaft 37 is set to be larger than the fitting length of the brush holder 48 and the case member 94 to the caliper body 16. When the speed reduction mechanism 35 and the electric motor 34 in the fixed state are assembled on the caliper body 16 side, the output rotation member 93 of the speed reduction mechanism 35 can be fitted to the screw shaft 37 in a relatively non-rotatable manner first. The fitting of the brush holder 48 and the case member 94 to the caliper body 16 can be guided, and the assembling property is further improved.

  In addition, the brush holder 48, which forms a part of the motor housing 46 together with the yoke 51, is fitted to the caliper body 16, so that the mounting position of the motor housing 46 to the caliper body 16 is accurately determined, and the armature 49 is also positioned. It becomes easy.

  Further, since the motor housing 46 having the brush holder 48 and the case 70 of the speed reduction mechanism 35 are fixed to the caliper body 16 by the common mounting bolts 72, the number of parts can be reduced.

  In such an electric motor 34, since the pulsar 58 to be detected by the rotation angle detection sensor 57 housed and arranged in the motor housing 46 is provided on the output shaft 47 in the motor housing 46, a waterproof seal is made. Since the rotation angle detection sensor 57 is accommodated in the motor housing 46, a special waterproof seal for the rotation angle detection sensor 57 becomes unnecessary, and the number of parts can be reduced.

  Further, since the rotation angle detection sensor 57 is accommodated and fixed in the recess 59 provided in the brush holder 48 so as to be covered with the cover plate 52 constituting a part of the motor housing 46, the yoke 51 is sandwiched between the brush holder 48. Before the motor housing 46 is assembled by connecting the cover plate 52 and the cover plate 52, the rotation angle detection sensor 57 has only to be accommodated and fixed in the recess 59 of the brush holder 48, so that the rotation angle detection sensor 57 can be easily assembled. It becomes.

  Further, the first motor bearing 56 provided between the output shaft 47 and the motor housing 46 outside the commutator 50 and the pulser 58 provided on the output shaft 47 between the commutator 50, the pulsar 58 is The output shaft 47 is provided at a position very close to the one motor bearing 56, and the detection accuracy of the rotation angle detection sensor 57 can be enhanced by preventing the pulsar 58 from running out as much as possible.

  In addition, the coupler 48a for detachably attaching the external connector 64 to the brush holder 48 is integrally provided, so that the structure can be simplified and the number of parts can be reduced.

  By the way, the motor housing 46 of the electric motor 34 includes a bottomed cylindrical yoke 51 that rotatably supports one end portion of the output shaft 47 at the closed end and coaxially surrounds the armature 49, and a brush 54 that is in sliding contact with the commutator 50. Are combined with a brush holder 48 holding the brush holder 48 between the open end of the yoke 51 and a cover plate 52 that rotatably supports the other end of the output shaft 47. The caliper body 16 is provided with a rear portion of a screw shaft 37 that constitutes a screw mechanism 36 together with a nut 38 that is accommodated in the hydraulic chamber 28 so as not to rotate relative to the brake piston 29 from the rear side. A partition wall 26 that is rotatable and liquid-tightly penetrated, and an accommodation recess 25 in which the partition wall 26 is interposed between the hydraulic chamber 28 are provided.

  Thus, the motor housing 46 has an annular shape that houses the case 70 in which the other end portion of the output shaft 47 is liquid-tightly protruded with the cover plate 52 as a constituent element in the housing recess 25 and surrounds the opening end of the housing recess 25. The speed reducing mechanism includes an output rotating member 93 that is attached to the caliper body 16 with the seal member 104 interposed between the caliper body 16 and that decelerates and outputs rotational power input from the other end of the output shaft 47. 35 is sealed in the case 70 while liquid-tightly protruding from the case 70 so that a part of the output rotating member 93 is coaxially linked and connected to the rear part of the screw shaft 37, and the case 70 is filled with grease 101. Has been.

  That is, the case 70 that seals the speed reduction mechanism 35 is configured with the cover plate 52 that is a part of the motor housing 46 in the electric motor 34 as a component, and the caliper body 16 is attached to the caliper body 16 according to the attachment of the motor housing 46 to the caliper body 16. Since the housing recess 25 is liquid-tightly accommodated, the case 70 can be simply configured so that the grease 101 filled in the case 70 does not leak, and can be easily attached to the caliper body 16. .

  The other end portion of the output shaft 47 coaxially connects the wave generator 84, the flex spline 87, the output side circular spline 91, and the output rotating member 93, which are rotating components among a plurality of components constituting the speed reduction mechanism 35. Therefore, the coaxial management of the components of the speed reduction mechanism 35 is facilitated, and the transmission efficiency can be prevented from being lowered due to the shaft misalignment.

  In addition, since the disc spring 102 that urges the output rotating member 93 in the axial direction is provided between the ball bearing 100 and the output rotating member 93 at a fixed position with respect to the case 70, the output rotating member provided in the speed reduction mechanism 35 is provided. 93 can be moved in the axial direction within the case 70 within a limited range, thereby absorbing a plurality of components constituting the speed reduction mechanism 35 and dimensional errors and assembly errors of the case 70 to reduce the speed reduction mechanism 35. Can be reliably accommodated in the case 70, and it is possible to prevent the output rotating member 93 from rattling during operation, thereby preventing the generation of operating noise and the decrease in operating efficiency.

  Further, when the disc brake is mounted on the rear wheel WR, the coupler 48a is disposed horizontally above and behind the rotation center C of the rear wheel WR, so that it flies from the front wheel WF side as shown in FIG. It is possible to guard the flying stepping stone etc. with the axle of the rear wheel WR and make it difficult to hit the coupler 48a, and to prevent the collision of the stepping stone etc. to the coupler 48a with a simple configuration that avoids an increase in the number of parts. it can.

  In addition, since the opening of the coupler 48a is disposed so as to be inclined obliquely downward on the rear side, the external connector 64 connected to the coupler 48a can be made difficult to hit a stepping stone or the like.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. der Ru.

1 is a longitudinal sectional view of a vehicle disc brake, taken along line 1-1 of FIG. 2 arrow view of FIG. 3-3 sectional view of FIG. Sectional view taken along line 4-4 in FIG. Sectional drawing which shows an electric motor and a reduction gear along 5-5 line of FIG. The figure which looked at the brush holder from the 6-6 line arrow direction of FIG. The figure which looked at the brush holder from the 7-7 line arrow direction of FIG. A view of the brush holder and yoke temporarily fixed with the motor cover removed and seen from the same direction as FIG. FIG. 5 is an enlarged sectional view taken along line 9-9. Sectional view taken along line 10-10 in FIG. 1 is an enlarged view of the main part of FIG. Side view of vehicle with disc brake mounted on rear wheel

16 ... caliper body 29 ... brake piston 37 ... screw shaft 38 ... nut 38a ... engagement part 42 ... corner part 43 ... locking groove

Claims (2)

A brake piston (29), which is formed in a bottomed cylindrical shape with an open rear end and can press the friction pad (17) at the front end in a cylinder hole (24) provided in the caliper body (16) , is slidable and rotatable. The output of the electric motor (34) can be transmitted to the brake piston (29) between the brake piston (29) and the electric motor (34) attached to the caliper body (16). a screw mechanism (36) is provided, the screw mechanism (36) comprises a brake piston (29) is disposed brake piston (29) and coaxial with the screw shaft behind and (37), the screw shaft ( 37) a vehicle disc brake including a nut (38) screwed onto the screw shaft and one of the screw shaft (37) and the nut (38) being non-rotatable.
A hydraulic chamber (28) in which the screw mechanism (36) faces is defined in the cylinder hole (24) on the back side of the brake piston (29), and a hydraulic pressure is set in the hydraulic chamber (28). A hydraulic path (32) leading to the caliper body (16),
One of the screw shaft (37) and the nut (38) is provided with an engaging portion (38a) whose outer periphery is a regular polygon in cross section,
The inner periphery of the front Symbol brake piston (29), said engaging portion is an integral multiple of the locking groove (43) of the number of the plurality of corner portions (38a) has (42), the circumferential direction while extending in the axial direction The corners (42) are selectively engaged with the locking grooves (43), and are provided at equal intervals .
The vehicle disc brake, wherein the locking groove (43) not engaged with the corner portion (42) is an air bleeding groove . 2. The vehicle according to claim 1, wherein an inner periphery of the brake piston is formed in a shape in which a plurality of regular polygons whose phases are shifted from each other when viewed in cross section are overlapped. Disc brake.

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