JP5466259B2 - Disc brake booster - Google Patents

Description

  In the present invention, a pad is pushed out by screwing an adjustment screw having an automatic gap adjustment function and a nut between a rotating shaft driven by a motor gear unit and a piston on the pad side to push a brake rotor. The present invention relates to a disc brake device that performs braking, and relates to a disc brake booster mechanism in which a booster mechanism constituted by a plurality of radial links is arranged between the rotating shaft and a nut.

  Conventionally, in a vehicle equipped with a brake, it is not necessary to install a cable and the cost can be reduced. Therefore, in recent years, a service brake is hydraulically operated and a parking brake is operated by a motor gear unit such as an electric motor. ing. The thing described in the following patent document 1 as a thing using such an electric parking brake was proposed.

JP 2003-65366 A (refer to the gazette abstract) JP 2010-190348 A (refer to the gazette abstract)

  The conventional electric parking brake disclosed in Patent Document 1 will be briefly described with reference to FIG. 7. In the form in which the inner and outer pads 102 and 103 sandwich the brake rotor (not shown) between the support 101 supported by the vehicle body. The cam roller type power conversion device 109 disposed and incorporated in the actuator case 108 expands and converts the rotational driving force of an electric motor (not shown) into axial thrust, and the thrust is transmitted to the gap adjusting device 110. Is transmitted to the piston 107 to press the inner pad 102 against the brake rotor, and the outer pad 103 is pressed from the opposite side of the brake rotor via the caliper 104 and the caliper claw 105 to perform braking. Thus, the parking brake can be easily performed simply by operating the switch of the electric motor.

  However, in such a conventional electric parking brake, a thrust increased to some extent by the cam roller type power conversion device 109 can be obtained. However, in order to obtain a large braking force, the electric motor has a large output. It was necessary to adopt a booster mechanism with a large boost ratio. Therefore, the present applicants have proposed a disc brake with an electric parking mechanism that employs a boosting mechanism as described in Patent Document 2. The disk brake with an electric parking mechanism described in Patent Document 2 will be briefly described with reference to FIG. 8. In an initial stage of braking, a drive rod 226 that is driven to rotate by an electric motor (not shown) is input via a pin 228. The screw 217 is rotated and rotated together with the adjustment screw 216 that is rotated around via the preset spring 218, and is screwed forward with respect to the adjuster plug 215, and the force-increasing mechanism 237 including the distribution levers 219 arranged radially is connected to the plug member. Braking is started by pressing an inner pad (not shown) to the brake rotor via 238.

  Further, when each of these members moves forward, the braking reaction force from the brake rotor becomes larger than the preset force of the preset spring 218, and the adjustment task screw 216 stops rotating due to screwing friction with the adjuster plug 215. As a result, only the input screw 217 continues to rotate, and the distribution lever 219 in the force-increasing mechanism 237 generates an axial force that swings and increases the inner diameter side end at a predetermined lever ratio with the recess 240 of the plug member 238 as a fulcrum. Let Thus, it has become possible to obtain a large parking force with a simple structure without using a high-output electric motor.

  The present invention further improves the disc brake with an electric parking mechanism proposed by the applicant of the present invention, so that a screw mechanism having an automatic gap adjusting function can be easily sub-assembled together with a booster mechanism, and is responsive and assembled. A disc brake booster mechanism that has excellent performance and can cope with uneven wear of pads is provided.

Therefore, the technical solution adopted by the present invention is:
A rotary shaft 1 to which a rotational driving force is transmitted from an electric motor housed in the caliper body 16 is transmitted, and a screw that rotates together with the rotary shaft 1 by spline or hexagonal fitting near the output end of the rotary shaft 1. 4, a plug nut that is screwed into a screw formed on the screw 4, an adjustment screw 11 that is rotationally driven from the screw 4 and the plug nut 5 via a booster mechanism in the axial force conversion unit 20, A nut 27 is provided that is screwed into the adjustment screw 11 and moves in the axial direction by the rotational drive of the adjustment screw 11. The movement of the nut 27 in the axial direction clamps both side surfaces of the brake rotor by the inner pad 18 and the outer pad 19. A disc brake booster mechanism capable of obtaining a braking force, wherein the rotary shaft 1 and an adjustment disc A booster mechanism composed of a plurality of radial links is disposed between the screw 11 and the screw 11. Further, the booster mechanism is sub-assembled in a case, and the adjustment screw 11 and the nut 27 are The screw portion by the screwing is urged in the direction opposite to the traveling direction by the urging force of the pressing spring disposed between the case and the adjusting screw 11, and is fitted to the rotary shaft 1. The screw portion of the plug nut 5 screwed into the screw 4 is urged in the forward direction by a pressing spring disposed between the case and the plug nut 5, and the urging force of each pressing spring is further increased. Thus, the screw between the screw 4 and the plug nut 5 that engages the rotary shaft 1 with the screwing frictional force of the screw portion between the adjusting screw 11 and the nut 27. A disc brake booster mechanism, characterized in that it has less than screwing friction parts.
Further, the outer diameter side of the plurality of radial links is locked to the end face of the adjusting screw, and the projection 11A formed on the large diameter part on the input side of the adjusting screw 11 is engaged with the notch of the case. The nut 27 that is positioned in the circumferential direction is engaged with the notch of the case, and the plug nut 5 that is screwed with the screw 4 is engaged with a protrusion 14A formed on the case. The adjusting screw 11, the nut 27, the plug nut 5, and the screw 4 are disc brake booster mechanisms configured to rotate together with the case .
The disc brake booster mechanism is characterized in that the inner diameter side ends of the plurality of links constituting the booster mechanism are in contact with a swingable joint disposed between the link and the rotary shaft side. It is.

According to the present invention, the adjustment screw having an automatic gap adjustment function between the rotating shaft driven by the motor gear unit and the pad-side piston and the nut, which are constituent elements of claim 1, are provided. A disc brake device that brakes by pushing the brake rotor when the pad is pushed out, and a disc brake doubling mechanism in which a booster mechanism composed of a plurality of radial links is arranged between the rotating shaft and the plug nut. In the force mechanism, the booster mechanism is sub-assembled in the case, and a screw portion by screwing the adjustment screw and the nut and a screw portion by screwing the screw fitted to the rotary shaft and the plug nut axially between nipped by arranging the pressing spring, before by applying a pressing force in the axial direction to the screw screwed portion of the screw and the plug nut and By making the screwing frictional force of the screw part of the adjusting screw and the nut smaller than the screwing frictional force of the screw part of the screw and the plug nut, the screw mechanism having an automatic gap adjusting function can be easily sub- It can be assembled, has excellent assemblability, is easy to manage components, has good responsiveness with a press spring, and a booster mechanism composed of links can provide a large braking force even with a low-power electric motor. The automatic gap adjusting function and the boosting function can be divided before and after the generation of the braking reaction force by the difference in screwing frictional force between the screw portions arranged on both sides of the boosting mechanism.

  Further, the outer diameter side of each link, which is a constituent requirement of claim 2, is positioned by a recess in the end face of the adjusting screw and a notch in the case, and the nut and the plug nut are engaged with the notch in the case. If it is configured to rotate together, it is easy to assemble with a simple structure, and each link, which is a booster mechanism, can be positioned reliably in the radial and circumferential directions, resulting in stable operation. It is done. Furthermore, the inner diameter side end portion of each link, which is a constituent requirement of claim 3, is in contact with the rotating shaft side via a swingable joint, so that caliper deformation or Even if the piston is tilted due to uneven wear of the pad, the inner diameter side end of each link is abutted and supported by a swingable joint composed of a spherical surface, etc. A stable boosting force is transmitted smoothly.

It is a principal part longitudinal cross-sectional view of the disc brake booster mechanism of this invention. It is the whole longitudinal cross-sectional view of a disk brake booster mechanism. 2 is an overall perspective view of the disc brake booster mechanism. FIG. It is an exploded perspective view of an automatic gap adjustment mechanism and a booster mechanism. It is an exploded perspective view of a booster mechanism. FIG. 5 is a perspective view of the automatic gap adjusting mechanism and the booster mechanism of FIG. It is explanatory drawing of the conventional electric parking brake. It is explanatory drawing of the disc brake with an electric parking mechanism which is a premise technique of this invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments for implementing a disc brake booster mechanism of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the disc brake booster mechanism of the present invention includes an adjustment screw 11 having an automatic clearance adjustment function between a rotating shaft 1 driven by a motor gear unit 15 and a piston 21 on the pad 18 side. A disk brake device in which the pad 18 is pushed out by screwing with a nut 27 and presses a brake rotor to perform braking, and a plurality of radial links 7 and 8 between the rotary shaft 1 and the nut 27 are provided. In the disc brake booster mechanism in which the booster mechanism is arranged, the booster mechanism is sub-assembled in the cases 10 and 14 and the screw portion A is formed by screwing the adjusting screw 11 and the nut 27 together. Between the screw 4 fitted on the rotary shaft 1 and the screw part B by screwing the plug nut 5 with the pressing springs 9 and 13. Pressurized, is characterized in that the screwing frictional force of the screw portion A between the adjusting screw 11 and the nut 27 is made smaller than the engagement frictional force of the screw portion B of the screw 4 and the plug nut 13.

  Embodiments of the disc brake booster mechanism of the present invention will be described below. As shown in FIG. 2, which is an overall longitudinal section of the figure, a caliper body 16 is fixed to a vehicle body stationary part via an appropriate support 17, and includes an electric motor housed in the caliper body 16 and an appropriate gear train. The rotational driving force from the motor gear unit 15 comprising the speed reduction mechanism is transmitted to the rotating shaft 1 having a rotating shaft parallel to the rotating shaft of the motor gear unit 15, and the rotating force of the rotating shaft 1 is in the vicinity of its output end. Are transmitted to the screw 4 that rotates together by spline or hexagonal fitting. From the screw 4, the adjusting screw 11 is rotationally driven through a booster mechanism included in an axial force conversion unit 20, which will be described in detail later, and a nut 27 that is screwed into the screw 27 is advanced in the axial direction, via the piston 21. The inner pad 18 is advanced, and both sides of the brake rotor (not shown) are pressed between the outer pad 19 and the outer pad 19 located on the back side via the caliper body 16 to obtain a braking force. FIG. 3 is an overall perspective view of the disc brake booster mechanism of the present invention, and the positional relationship among the motor gear unit 15 including the speed reduction mechanism, the support 17, the caliper body 16, and the pads 18, 19 is clearly understood.

  The disc brake booster mechanism of the present invention will be described in detail with reference to FIG. 1, which is an enlarged longitudinal sectional view of the main part from the rotating shaft 1 to the inner pad 18 in FIG. The axial force conversion unit 20 converts a rotational force around the rotational axis of the rotary shaft 1 into an axial force, and a plug nut 5 that is screwed to the screw 4 that rotates together with the rotary shaft 1. Including a mechanism that involves axial movement of the nut 27, generation of axial force due to the swinging of the links 7, 8, and axial movement of the nut 27 that is screwed into the adjusting screw 11. A screw 4 that rotates together with the rotating shaft 1 by spline or hexagonal fitting is fitted to the output side end portion of the rotating shaft 1 to which the rotational driving force is transmitted from the motor gear unit 15, and the output side of the screw 4 A joint 6 that is swingable by a spherical surface or the like is accommodated in the concave portion of the end surface. A plug nut 5 is screwed onto the outer periphery of the screw 4 to form a screw portion B. In the plug nut 5, the screwing frictional force of the screw portion B is set by the pressing spring 13 accommodated in the second case 14.

  On the output side of the plug nut 5, a thrust plate 12, a plurality of radial links 7 and 8, and an adjusting screw 11 are sequentially arranged. The adjusting screw 11 can move in the axial direction by rotating together with a piston 21. A nut 27 is screwed together to form a screw portion A. The screwing frictional force of the screw part A is set so that the pressing force of the pressing spring 9 does not act. The screw portion A of the nut 27 screwed to the adjusting screw 11 constituting the automatic gap adjusting mechanism urges the adjusting screw 11 in the direction opposite to the traveling direction by a large spring force by the pressing spring 9. The screw frictional force is reduced. On the other hand, in the screw part B, the plug nut 5 is urged in the forward direction by a small spring force by the pressing spring 13. Therefore, since the screwing frictional force of the screw part A is smaller than that of the screw part B, the nut 27 is relatively advanced by the screw part A in the initial stage of braking and the automatic clearance adjustment function is exhibited. Will move forward.

  FIG. 4 is an exploded perspective view of each member described above, and it is well understood that the members are sub-assembled between the first case 10 and the second case 14. The nut 27 is screwed into the adjustment screw 11, but is finally located outside the first case in the axial direction (see FIG. 6). As is well understood in the exploded perspective view of FIG. 5, the outer diameter side of the plurality of radial links 7 and 8 constituting the boosting mechanism is engaged with the concave portion 11B of the end face of the adjusting screw 11 so that the radial direction and the shaft It is also positioned reliably in the direction. As can be understood from FIG. 6, the outer diameter sides of the links 7 and 8 are simultaneously engaged with the axial cutouts 10C in the first case 10 for positioning in the circumferential direction (first case 10). However, the second case 14 is free (see FIG. 6A). As shown in FIG. 4, since the cut and raised piece 14 </ b> A of the second case 14 contacts the cut surface 5 </ b> A on the circumference of the plug nut 5, the plug nut 5 also rotates together with the second case 14.

On the other hand, a protrusion 11A is formed on the large diameter portion on the input side of the adjusting screw 11 in which the outer diameter side of the links 7 and 8 is accommodated and locked. As can be understood from FIG. The notch 10C of the first case 10 and the notch 14C of the second case 14 are engaged and positioned in the circumferential direction (the adjust screw 11 rotates together with the first case 10 and the second case 14). To do). The first case 10 and the second case 14 are divided in the axial direction to facilitate assembly when sub-assembling, but the protrusions of the members and the like are not locked to the notches of the case. If it is solved, it does not exclude that each case is constituted by one member by utilizing a cut and raised piece at the case end. As shown in FIG. 6, two protrusions 27 </ b> A are formed on the outer periphery of the nut 27. This is because the nut 27 screwed into the adjustment screw 11 is accommodated in the corresponding axial concave groove of the piston 21. The piston 21 rotates together with the piston 21 so as to be movable only in the axial direction, and comes into contact with the piston 21 in the inner pad pressing direction.

  The disc brake booster of the present invention configured as described above operates as follows. As shown in FIG. 1 with reference to FIGS. 4 to 6, as described above, in the initial stage of braking, the motor is rotated by the rotational driving force from the motor gear unit 15 including the reduction mechanism including the electric motor and an appropriate gear train. The shaft 1 rotates and is transmitted to the screw 4 that rotates together by spline or hexagonal fitting at its output end. The rotation of the screw 4 tends to cause relative rotation in the screw portion B between the screw nut B and the plug nut 5 screwed into the screw nut. As described above, the screwing frictional force of the screw portion B is caused by the adjusting screw 11. As the screw 4 is larger than the screwing frictional force of the screw part A between the nut 27 and the screw 27, only the screw part A operates, and the nut 27 is screwed so that the nut 27 can be rotated relative to the screw 27. The plug nut 5 is rotated, and the second case 14 rotates together with the rotary shaft 1 by the engagement between the cut surface 5A of the plug nut 5 and the cut and raised piece 14A of the second case 14.

When the second case 14 rotates, the adjustment screw 11 in which the protrusion 11A at the large diameter portion engages with the notch 14C of the second case 14 also rotates together with the second case 14, and further, the protrusion 11A is in the first case. Since the 10 notches 10C are also engaged, the first case 10 also starts rotating together. As the adjusting screw 11 is driven to rotate, the nut 27 screwed into the screw portion A is advanced in the axial direction (the nut 27 can move only in the axial direction with respect to the piston 21 but cannot rotate). . The inner pad 18 is advanced through the piston 21 by the advance of the nut 27, and both sides of the brake rotor (not shown) are sandwiched between the outer pad 19 (see FIG. 2) positioned on the back side through the caliper body 16. Braking force is obtained. At this time, an automatic gap adjustment function for automatically filling only the increased stroke due to wear of the pads 18 and 19 is performed.

  When a braking force is obtained by sandwiching both side surfaces of the brake rotor and a braking reaction force generated thereby is generated, a pressing force in the input direction is generated on the piston 21, and a screw portion A between the nut 27 and the adjusting screw 11 is generated. As the large screwing frictional force acts to stop the rotation of the adjusting screw 11, the first case 10 and the second case 14 also stop. However, the rotary shaft 1 and the screw 4 still continue to rotate, and the plug that rotates together with the second case 14 due to the engagement between the cut-and-raised piece 14A of the second case 14 and the cut-out portion 5A of the plug nut 5 is used. Since the nut 5 does not rotate with the second case 14, the screw portion B causes relative rotation by the rotation of the rotating shaft 1, and the screw 4 is advanced.

  When the screw 4 moves forward, a plurality of radial links 7, 8 are swung at a predetermined lever ratio, that is, a boost ratio by using the recesses 11 </ b> B of the adjust screw 11 as fulcrums via the joint 6. A self-boosting function is achieved in which the thrust rotor 11, the nut 27, the piston 21, and the inner pad 18 that are generated and stopped are applied with axial thrust to brake the brake rotor with a larger braking force. become.

  In FIG. 2, 2 is a seal of the rotary shaft 1 with respect to the caliper body 16, 3, 24, 25 are bearing washers, 22 is a boot, 26 is a retaining ring, and 23 is a seal of the piston 21 with respect to the caliper body 16. 1, 4, and 6, reference numeral 10 </ b> A denotes an engaging cut-and-raised piece cut and raised on the outer periphery of the first case 10. This is an anchoring tool when the subassembly is engaged. Although detailed explanation is omitted, the pressure chamber 28 provided at the input side end of the piston 21 in FIG. 1 is for the pressure oil of the main service brake to act.

  Thus, according to the disc brake booster mechanism of the present invention, the screw mechanism constituted by the nut 27 screwed to the adjustment task screw 11 also having the automatic clearance adjustment function can be easily multiplied by the plurality of radial links 7 and 8. Can be assembled into sub-assemblies with the case 10 and 14 together with the force mechanism, easy to assemble and easy to manage parts, and can select the appropriate pressure springs 9 and 13 to optimize the responsiveness. A simple booster mechanism can provide a large braking force even with a low-power electric motor, and the braking reaction force can be reduced by the difference in screwing frictional forces of the screw parts arranged on both sides of the booster mechanism. It became possible to divide the automatic gap adjustment function and the boost function before and after the occurrence of.

  In addition, the first case 10 and the second case 14 hold each member arranged in the axial direction from both sides in the axial direction, and can be easily assembled with a simple structure and is a booster mechanism. Each link 7, 8 can be reliably positioned in the radial direction and the circumferential direction by the recess 11 </ b> B of the adjuster screw 11, and a stable operation can be obtained. Further, the inner diameter side end of each of the links 7 and 8 is abutted and supported with the rotary shaft 1 side via a swingable joint 6 such as a spherical support, so that caliper deformation or Even if an inclination or the like occurs in the piston 21 that occurs during the uneven wear of one pad, the inner diameter side ends of the links 7 and 8 are supported by the swingable joint 6, so that an uneven load is applied. Therefore, a stable boosting force is smoothly transmitted.

  As described above, the embodiments of the present invention have been described. However, within the scope of the present invention, the shape and type of the electric motor in the motor gear unit and the form of the speed reduction mechanism on the rotating shaft (the gear parallel to the rotating shaft). In addition to the row, it can also be decelerated by bevel gear engagement, pinion and worm engagement), the reduction rate of the speed reduction mechanism, the rotational axis and screw, and the nut and piston are allowed to move in the axial direction and rotate together ( If the relative rotation is impossible, an appropriate fitting form may be employed in addition to the fitting between the axial ridge and the corresponding groove, spline, hexagonal fitting), a plurality of radial radii constituting the booster mechanism The shape of the link, the number of the links, the screwing frictional force of the screw part of the adjusting screw and the nut is made smaller than the screwing frictional force of the screw part of the rotating shaft and the plug nut (one set of pressing in the embodiment) Arrangement of spring In addition to being pressed against each screw part, the surface of the screw part may be used in combination with low friction processing), plug nuts, links, and adjusting screws in their respective cases (axial protrusions on the case inner periphery) Forming a groove and forming a recessed groove on the outer periphery of the plug nut, link, and adjusting screw (in this case, the relative rotation between the cases is made impossible by the protruding groove and the recessed groove), and the link to the adjusting screw Support form in the concave portion (in the embodiment, the concave portion corresponding to the thickness of the link may be used in addition to the linear long groove concave portion on the end surface of the adjusting screw), the joint on which the inner diameter side end portion of the link is abutted and supported is swingable The form (support by the spherical surfaces of the joint and the screw, as well as support of the joint by the tumbler-like point contact, etc.) can be selected as appropriate. In addition, the specifications described in the examples are merely examples in all respects and should not be interpreted in a limited manner.

  The disc brake booster mechanism of the present invention is preferably used for an electric parking brake used in combination with a hydraulic service brake, but can also be used as a main brake in an electric vehicle or the like.

DESCRIPTION OF SYMBOLS 1 Rotating shaft 5 Plug nut 7 Link 8 Link 9 Press spring 10 1st case 11 Adjustment screw 13 Press spring 14 2nd case 15 Motor gear unit 18 Inner pad 21 Piston 27 Nut A Screw part B Screw part

Claims (3)

A rotary shaft 1 to which a rotational driving force is transmitted from an electric motor housed in the caliper body 16 is transmitted, and a screw that rotates together with the rotary shaft 1 by spline or hexagonal fitting near the output end of the rotary shaft 1. 4, a plug nut that is screwed into a screw formed on the screw 4, an adjustment screw 11 that is rotationally driven from the screw 4 and the plug nut 5 via a booster mechanism in the axial force conversion unit 20, A nut 27 is provided that is screwed into the adjustment screw 11 and moves in the axial direction by the rotational drive of the adjustment screw 11. The movement of the nut 27 in the axial direction clamps both side surfaces of the brake rotor by the inner pad 18 and the outer pad 19. A disc brake booster mechanism capable of obtaining a braking force, wherein the rotary shaft 1 and an adjustment disc A booster mechanism composed of a plurality of radial links is disposed between the screw 11 and the screw 11. Further, the booster mechanism is sub-assembled in a case, and the adjustment screw 11 and the nut 27 are The screw portion by the screwing is urged in the direction opposite to the traveling direction by the urging force of the pressing spring disposed between the case and the adjusting screw 11, and is fitted to the rotary shaft 1. The screw portion of the plug nut 5 screwed into the screw 4 is urged in the forward direction by a pressing spring disposed between the case and the plug nut 5, and the urging force of each pressing spring is further increased. Thus, the screw between the screw 4 and the plug nut 5 that engages the rotary shaft 1 with the screwing frictional force of the screw portion between the adjusting screw 11 and the nut 27. Disc brake servo mechanism, characterized in that it has less than screwing friction parts. The outer diameter side of the plurality of radial links is locked to the end face of the adjusting screw, and a protrusion 11A formed on the large diameter portion on the input side of the adjusting screw 11 engages with the notch of the case to move in the circumferential direction. The nut 27 that is screwed to the adjustment screw 11 is engaged with a notch of the case, and the plug nut 5 that is screwed to the screw 4 is engaged with a protrusion 14A formed on the case. 2. The disc brake booster mechanism according to claim 1, wherein the adjusting screw 11, the nut 27, the plug nut 5, and the screw 4 are configured to rotate together with the case. 2. The disk according to claim 1, wherein the inner diameter side end portions of the plurality of links constituting the booster mechanism are in contact with a swingable joint disposed between the rotary shaft side and the plurality of links. Brake boost mechanism.

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