JP2012197933A - Automatic gap adjustment mechanism for wedge/cam brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic gap adjustment mechanism for a wedge/cam brake which provides excellent assembly and simple structure, does not require high precision, allows a gap adjustment to be made stably, does not cause braking force reduction, and clearly distinguishes an ordinary stroke from an excessive stroke.SOLUTION: When an excessive stroke occurs, a relative position of an adjustment rod 22 fit in a front end 11A of a cam shaft 11 is adjusted in an axial direction against a stationary part (a sleeve 20) to change an initial position of the cam shaft 11 in the axial direction. In the front end 11A of the cam shaft 11 itself, a gap adjustment at the excessive stroke can be axially made, thereby allowing a stable gap adjustment to be made limitlessly in a wide range in response to an amount of pad wear even with a single adjustment mechanism and avoiding the risk of braking force reduction by securing control even when a component is damaged.

Description

  The present invention relates to a wedge cam type brake in which a base end portion of a brake arm is expanded and oscillated by the cam action of the wedge cam by the axial movement of the cam shaft on which the wedge cam is formed. The present invention also relates to an automatic clearance adjustment mechanism for a wedge cam type brake configured to fill a swinging clearance of the brake arm.

  2. Description of the Related Art Conventionally, in a disc brake for a vehicle equipped with a brake, particularly a railway vehicle, the base end portions of a pair of brake arms are expanded and pad assemblies provided at the open end portions thereof are arranged on both sides of the brake rotor (disc rotor). There is known an insulator-type caliper brake that performs a brake operation by pinching from the outside. In these lever-type caliper brakes, when the pad assembly is worn, the time when the brake starts to work is delayed and the braking distance becomes long. Therefore, an adjuster mechanism, which is a clearance adjustment mechanism, is usually disposed between the actuator and the base end portion of the brake arm so that an excessive stroke does not occur in the brake arm. As such an adjuster mechanism, for example, there is a brake cylinder described in Patent Document 1 below.

JP 2008-164159 A (refer to the gazette abstract)

  As shown in FIG. 9, the brake cylinder disclosed in Patent Document 1 is attached to the piston 103 that moves relative to the cylinder body 102, the shaft rod 104 that moves together with the piston 103, and the shaft rod 104. A push rod 105 and a projection length adjusting means 106 for adjusting a projection length of the push rod 105 from the cylinder main body 102 when the brake is operated. The push rod 105 is parallel to the moving direction of the piston 103. And a female screw 151 is screwed into at least a part of the inner surface of the shaft hole, and the shaft rod 104 is screwed with the female screw 151 into at least a part of the outer surface. The mating male screw 141 is threaded and inserted into the shaft hole, and the engaging portion 142 is engageable with a rotational force applying means for applying a rotational force around the shaft from the outside. Those having.

  In the brake cylinder 101 having such a protrusion length adjusting means 106, the piston 103 is connected via the shaft rods 104 and 105 as shown in FIG. 9B by supplying pressure into the pressure chamber 102b. The member 107 is moved in the expanding direction with respect to the first casing 121 in the cylinder body 102. As a result, a brake arm (not shown) connected to each of the connecting member 107 and the first casing 121 is swung to perform a braking operation. When wear occurs in the pad assembly, the cover 108 is removed, and a socket such as a handle wrench is externally engaged with the engaging portion 142 of the shaft rod 104 to rotate the female screw 151 of the push rod 105. By moving the male screw 141 of the shaft rod 104 into engagement with the shaft rod 104 to increase the axial distance between the shaft rod 104 and the push rod 105, it is possible to adjust the gap to suppress the excessive stroke of the brake arm.

  Further, when the braking surface of the brake pad is worn, the required stroke of the push rod 105 for operating the brake is increased, and the stroke of the guide member 161 through the uneven surface 152 is increased, resulting in an excessive stroke. When the restricting body 165 comes into contact with the stopper 166, a large return force acts on the guide member 161, so that the push rod 105 is displaced in the protruding direction over the uneven surface 152. In this way, automatic clearance adjustment that suppresses excessive stroke of the brake arm is performed.

  However, in such a conventional adjuster mechanism, adjustment work is manually performed using a handle wrench or the like from the outside, and the work is troublesome. This is likely to occur, and manual adjustment work using a handle wrench or the like from the outside is performed between the push rod 105 and the shaft rod 104, so that an excessively large portion is engaged in the threaded portion between the female screw 151 and the male screw 141. When the force acts and the screwing portion is damaged, there is a possibility that the braking force is reduced. Further, in the case of the automatic clearance adjustment that suppresses the excessive stroke of the brake arm, although it is made by the progress of the push rod 105 side over the uneven surface 152 between the push rod 105 and the guide member 161, the regulating body 165 or An extra member such as the stopper 166 is required to form a complicated structure, and there is a high possibility that the gap adjusting function is deteriorated due to damage of these components.

  Therefore, in the present invention, the problems in the conventional adjuster mechanism are solved, and the gap adjustment can be stably performed without requiring high accuracy with a simple structure excellent in assemblability, and the brake force may be reduced. It is another object of the present invention to provide an automatic clearance adjustment mechanism for a wedge cam type brake that can clearly distinguish a normal stroke and an excessive stroke.

  For this reason, the present invention is a wedge cam type brake in which the base end portion of the brake arm is expanded and oscillated by the cam action of the wedge cam by the axial movement of the cam shaft forming the wedge cam. In an automatic clearance adjustment mechanism of a wedge cam type brake configured to fill the rocking clearance of the brake arm when it occurs, the adjustment rod fitted to the tip of the camshaft is stationary when the excessive stroke occurs The initial position in the axial direction of the camshaft is changed by adjusting the relative position in the axial direction with respect to the portion. In the invention, it is preferable that the adjustment rod is fitted to an inner periphery of a sleeve member fixed to the body via a friction member. According to the present invention, when the excessive stroke occurs, the front end surface of the wedge cam abuts against the rear end surface of the adjustment rod, and the relative position in the axial direction of the adjustment rod with respect to the sleeve member is changed. Further, the present invention is characterized in that the original position in the axial direction with respect to the stationary portion via the adjustment rod of the camshaft is reset by pressing the adjustment rod from the outside via the release plug. These are the means for solving the problems.

  According to the present invention, there is provided a wedge cam type brake which is a constituent element of claim 1 and which swings the base end portion of the brake arm by the cam action of the wedge cam by the axial movement of the cam shaft forming the wedge cam. The wedge cam type brake automatic gap adjustment mechanism configured to fill the swinging gap of the brake arm when an excessive stroke occurs in the camshaft, the tip of the camshaft when the excessive stroke occurs By adjusting the axial position of the adjustment rod fitted to the stationary part in the axial direction and changing the initial axial position of the camshaft, the tip of the camshaft itself is excessively stroked in the axial direction. Can be adjusted over a wide range with respect to pad wear even with a single adjustment mechanism. That on, parts to damage control is ensured even if.

In addition, when the adjustment rod is fitted to the inner periphery of the sleeve member fixed to the body via the friction member, the camshaft slides in the adjustment rod during a normal stroke. In the case of excessive stroke due to pad wear, a combination of extremely simple structures, such as the presence of a friction member, makes it possible to easily and continuously move the axial position of the adjustment rod relative to the sleeve member, which is a stationary part, to prevent pad wear over a wide range. On the other hand, automatic clearance adjustment can be performed.
Furthermore, when the excessive stroke occurs, the front end surface of the wedge cam abuts against the rear end surface of the adjustment rod, and the relative position of the adjustment rod in the axial direction with respect to the sleeve member is changed. In this case, a simple configuration in which the front end surface of the wedge cam just abuts against the rear end surface of the adjustment rod, and there is no risk of failure or damage. Is simple and easy.

  Furthermore, the original position in the axial direction with respect to the stationary portion via the adjustment rod of the camshaft is reset by pressing the adjustment rod from the outside via the release plug, which is a constituent requirement of claim 4. When configured, the axial position of the adjustment rod relative to the stationary portion, that is, the sleeve member can be easily reset to the original position simply by pressing the adjustment rod from the outside via the release plug when replacing the pad.

It is a principal part plane sectional view of the 1st example provided with the automatic gap adjustment mechanism of the wedge cam type brake of the present invention. FIG. 2 is an exploded perspective view of the automatic gap adjustment mechanism. It is a principal part top sectional view showing an initial state of an automatic gap adjustment mechanism same as the above. It is a principal part plane sectional view which shows the normal brake operation state of an automatic clearance gap adjustment mechanism. FIG. 3 is a plan cross-sectional view of a main part showing a brake operating state immediately before clearance adjustment (adjustment) due to excessive stroke of the automatic clearance adjustment mechanism. FIG. 6 is a plan cross-sectional view of the main part showing the brake operating state during clearance adjustment of the automatic clearance adjustment mechanism. FIG. 6 is a plan cross-sectional view of the main part showing the brake non-operating state after the clearance adjustment of the automatic clearance adjustment mechanism. It is a schematic diagram of the clearance adjustment process by the relationship between the automatic clearance adjustment mechanism and the pad assembly via the brake arm. It is explanatory drawing of the brake cylinder provided with the conventional clearance gap adjustment mechanism.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for implementing an automatic clearance adjustment mechanism for a wedge cam brake according to the invention will be described with reference to the drawings. As shown in FIG. 1, the automatic clearance adjustment mechanism of the wedge cam type brake according to the present invention is based on the cam action of the wedge cam 10 by the axial movement of the cam shaft 11 forming the wedge cam 10, and the base ends of the brake arms 4, 4 Wedge cam type brake that swings and expands a portion of the wedge cam type brake automatic gap adjustment mechanism configured to fill the rocking gap of the brake arms 4 and 4 when an excessive stroke occurs in the camshaft 11 When the excessive stroke occurs, the relative position in the axial direction of the adjustment rod 22 fitted to the tip of the camshaft 11 is adjusted with respect to the stationary portion (sleeve member 20) to adjust the axis of the camshaft 11. The initial position of the direction is changed.

  Hereinafter, a first embodiment of the automatic clearance adjustment mechanism of the wedge cam type brake of the present invention will be described. The body 1 is fixed to the vehicle body stationary part through an appropriate support. As shown in the schematic diagram of FIG. 8, the middle part of the pair of brake arms 4 and 4 on both lower sides of the body 1 (not shown in FIG. 8). Is supported by the brake arm shafts 5 and 5. Pad assemblies 6 and 6 are attached to the open ends of the upper parts of the brake arms 4 and 4 via brake holders. As shown in FIG. 1, a link rod 15 constituting an output shaft connected and supported by a spherical bush 14 to a roller arm 13 of a link type booster as shown in FIG. The outer end is supported by the spherical bush 16. In the example of FIG. 8, the cam roller 12 pushed and spread by the wedge cam 10 is not the link type booster configured by the roller arm 13 or the like, and the base end portion of the brake arm 4 is directly expanded via the link rod. The format is Of course, even in FIG. 8, a link-type booster equipped with the roller arm 13 as shown in FIG. 1 may be used.

  As shown in FIG. 1, when air is introduced from the supply port 7 to fill the pneumatic chamber 8A, the air piston 8 operates against the restoring force of the chamber spring 9 on the other side in the axial direction (lower side in the drawing). The air cylinder 2 is disposed on one side (the upper side in the drawing) of the camshaft 11. Along with the movement of the camshaft 11 in the other axial direction, cam rollers 12 and 12 that ride on the inclined surface of the wedge cam 10 formed by being attached to the camshaft 11 by the nut 24 are disposed. For example, the cam rollers 12 and 12 constitute a link type booster. The cam rollers 12 and 12 are respectively connected to one end of a pair of roller arms 13 and 13 that are supported by bearings 18 and 18 at both ends of the strut 19. It is supported. When the cam rollers 12 and 12 are lifted onto the inclined surface of the wedge cam 10, the roller arms 13 and 13 swing in the expanding direction, and are connected and supported by a spherical bush 14 at a substantially intermediate portion of the roller arms 13 and 13. The link rods 15 and 15 are boosted by the lever principle and axially moved outward (left and right in the drawing). As a result, the base end portions of the brake arms 4 and 4 are moved in the expanding direction with the arm shaft 5 as the swing center, and are disposed on the open end portions (the back side of the paper in FIG. 1) of the brake arms 4 and 4. The brake operation is performed by pressing the pad assemblies 6 and 6 (see FIG. 8) against the disc rotor 3.

  One automatic clearance adjustment mechanism is disposed on the end 11A side of the camshaft 11 that is on the opposite side of the air cylinder 2 in the axial direction. The automatic gap adjusting mechanism includes a sleeve member 20 supported with respect to the body 1 that is a stationary part, an adjustment rod 22 fitted to the inner periphery thereof, and a slidably fitted inside the adjustment rod 22. Further, the camshaft 11 and the wedge cam 10 whose front end face comes into contact with the rear end face of the adjusting rod 22 at the time of excessive stroke. On the inner peripheral surface of the sleeve member 20, a friction member that acts on the outer peripheral surface of the adjusting rod 22 and regulates the sliding of each other with a predetermined frictional force (resistance force due to the friction> restoring force of the chamber spring 9). 21 is disposed and is prevented from coming off by the retaining ring 17. A bush 23 is press-fitted into the inner peripheral surface of the adjusting rod 22 between the inner peripheral surface of the adjusting rod 22 and the outer peripheral surface of the camshaft 11. As clearly shown in FIG. 7, a large diameter portion 11 </ b> B is formed at the tip end portion 11 </ b> A of the camshaft 11, and abuts against a small diameter step portion 22 </ b> A formed in the middle of the adjustment rod 22. It comes into contact with the adjusting rod 22 and is prevented from coming off. (In FIG. 7, the adjusting rod 22 is about to be returned to the return position by the camshaft 11 due to the restoring force of the chamber spring 9, but the frictional force with the friction member 21 is larger and the adjusting rod 22 returns after adjusting the clearance. Never)

  Further, as shown in FIG. 1, after the gap adjustment is performed by an excessive stroke as will be described later in FIGS. 6 and 7, the adjustment rod 22 that protrudes to the other side (brake operating direction) with respect to the sleeve member 20 is provided. A release plug 29 for pressing from the outside is disposed on the other side of the body 1. Reference numeral 25 denotes a cap that covers the release plug 29. Reference numeral 27 denotes a return spring of the release plug 29. When replacing a new pad assembly or the like, the initial position in the axial direction of the camshaft 11 can be changed and easily reset to the original position in the axial direction by inward pressing by the release plug 29. New parts such as assemblies can be replaced quickly.

  FIG. 2 is an exploded perspective view showing the automatic clearance adjustment mechanism employed in the wedge cam type brake of the present invention in an easily understandable manner. As described above, one automatic gap adjustment mechanism is configured and disposed on the distal end portion 11A side of the camshaft 11. As shown in FIG. 2 with reference to FIG. 1, the automatic gap adjustment mechanism includes a sleeve member 20 supported with respect to the body 1 that is a stationary part, an adjustment rod 22 fitted to the inner periphery thereof, The camshaft 11 is slidably fitted in the adjusting rod 22, and the wedge cam 10 has a front end face that abuts on the rear end face of the adjusting rod 22 when the stroke is excessive. The sleeve portion of the sleeve member 20 is fitted with an adjustment rod 22 in which a bush 23 for guiding the tip end portion 11A of the camshaft 11 is press-fitted into the inner peripheral surface, and an intermediate small diameter step portion 22A (see FIG. 3), the large diameter portion 11B of the tip portion 11A of the camshaft 11 is further fitted. A friction member 21 is disposed between the sleeve member 20 and the adjustment rod 22, and the friction member 21 is prevented from coming off by a retaining ring 17 installed between the sleeve member 20 and the friction member 21. The camshaft 11 is fastened to the wedge cam 10 by a nut 24 that is screwed into the proximal end portion of the camshaft 11 inserted through the sleeve member 20 and the wedge cam 10. Note that the inner diameter hole of the sleeve portion of the sleeve member 20 is a tapered hole that becomes wider toward the retaining ring 17 side, so that the adjuster operates loosely to suppress caliper efficiency loss, and the return side operates tightly. It can also be considered that the adjuster does not return due to the vibration of the vehicle. At this time, the configuration of the friction member 21 may be a corresponding tapered shape.

  FIG. 3 is a plan cross-sectional view of the main part showing an initial state of the automatic gap adjustment mechanism, and the body, the air cylinder, the release plug, and the like are not shown. The same diagram as FIG. 1 shows an initial state in which the brake is not activated as well as the automatic gap adjusting mechanism, and the camshaft 11 is moved to the other side in the axial direction against the restoring force of the chamber spring 9 of the air piston 8 (not shown). When operated to the lower side, cam rollers 12 and 12 are attached to the inclined surface of the wedge cam 10 formed by being attached to the camshaft 11 as shown in FIG. Get on. As a result, for example, the pair of roller arms 13 and 13 that are pivotally supported by the bearings 18 and 18 at both ends of the strut 19 constituting the link type booster expand outwardly with the bearings 18 and 18 as pivot points. The link rods 15, 15 connected and supported by the spherical bush 14 on the substantially intermediate portion of the roller arms 13, 13 are boosted by the lever principle and axially moved outward (left and right in the drawing). Thus, as shown in FIG. 8, the base end portions of the brake arms 4, 4 are moved in the expanding direction with the arm shaft 5 as the swing center, and are disposed at the open end portions of the brake arms 4, 4. The brake operation is performed by pressing the pad assemblies 6 and 6 against the disc rotor 3.

  As understood from FIG. 4, the camshaft 11 has a large diameter portion 11 </ b> B at its tip, a bush 23 pressed into the adjustment rod 22, and a small diameter step portion 22 </ b> A at the inner periphery of the adjustment rod 22. Since it is stably supported at a plurality of locations and can move in the adjustment rod 22 in the axial direction, the roller arms 13 and 13 are expanded by the inclined surface of the wedge cam 10 and the link rods 15 and 15 are interposed. Brake operation will be performed. When the brake operation is released from the state shown in FIG. 4, the camshaft 11 moves backward in the drawing to return to the initial position. The large-diameter portion 11B at the tip end portion of the camshaft 11 comes into contact with the small-diameter step portion 22A in the adjustment rod 22 and becomes the initial position.

  FIG. 5 is a cross-sectional view of the main part showing the brake operating state immediately before the gap adjustment (adjustment) due to the excessive stroke of the automatic gap adjusting mechanism, and FIG. 6 is the main part flat showing the brake operating state during the gap adjustment of the automatic gap adjusting mechanism. It is sectional drawing. When the pad or the like is worn, the swinging stroke of the brake arm 4 (not shown) increases, and as a result, the stroke of the camshaft 11 deviates from the normal range and moves to the other side (lower side in the drawing) in the axial direction due to excessive stroke. Moving. As a result, as shown in FIG. 5, the front end surface of the wedge cam 10 comes into contact with the rear end surface of the adjustment rod 22. When the camshaft 11 further advances as shown in FIG. 6 due to excessive stroke, the sleeve exceeds the resistance value due to friction of the friction member 21 disposed between the sleeve member 20 which is a stationary portion and the adjusting rod 22, and the sleeve The adjustment rod 22 advances relative to the member 20 and protrudes. The gap adjustment has been completed.

  FIG. 7 is a cross-sectional plan view of the main part showing the brake non-operating state after the clearance adjustment of the automatic clearance adjustment mechanism. When the clearance adjustment is completed, the camshaft 11 returns from the state of FIG. 6 to the initial position in the adjustment sleeve 22 by the chamber spring 9 (not shown). The large-diameter portion 11B at the tip of the camshaft 11 comes into contact with the small-diameter step portion 22A of the adjustment rod 22 and reaches the initial position (FIG. 7). The adjustment rod 22 is relatively protruded from the sleeve member 20 by the clearance adjustment compensated to fill the swinging clearance of the brake arm caused by the excessive stroke caused by the wear of the pad or the like. Therefore, the initial position of the camshaft 11 after the clearance adjustment is at a position where the wedge cam 10 has advanced by the amount of the protrusion of the adjustment rod 22 whose clearance is adjusted from the original position, and therefore the inclined surface of the wedge cam 10 and the cam engagement The roller arms 13 and 13 are also in an expanded state. That is, a gap adjustment state that has advanced in advance by the amount of wear of the pad or the like appears.

  FIG. 8 is a schematic diagram of a gap adjustment process in relation to the automatic gap adjustment mechanism and the pad assembly via the brake arm. In FIG. 8, the illustration of the sleeve member 20 attached to the stationary body is omitted. 8A, the wedge cam 10 and the cam shaft 11 advance, the base end portion of the brake arm 4 expands via the cam rollers 12 and 12, and the arm shaft 5 that is the swing fulcrum is the center. The pad assembly 6 that swings and is mounted on the open end is sandwiched and pressed against the side surface of the disk rotor 3 to enter the brake operating state shown in FIG. At this time, the camshaft 11 advances relative to the adjustment rod 22.

  FIG. 8C shows a state in which the pad in the pad assembly 6 is worn and the gap is adjusted by the automatic gap adjustment mechanism, and the adjustment rod 22 of the sleeve member 20 (not shown) is in a protruding state in which the adjustment rod 22 has advanced. In addition, a state corresponding to FIG. 7 in which the brake is not activated, in which the pad assembly 6 is not in contact with the disk rotor 3, is shown. In FIG. 8D, the wedge cam 10 and the camshaft 11 are both advanced to swing the brake arm 4 to the operating position, and the pad assembly 6 attached to the open end of the brake arm 4 is sandwiched between the side surfaces of the disc rotor 3. The state where the brake is pressed is shown.

  As described above, the embodiments of the present invention have been described. However, within the scope of the present invention, the shape of the wedge cam, its mounting form on the camshaft, and the related configuration of the wedge cam and the brake arm base end (cam A link rod having a link rod interposed between a pair of link type boosters as in the embodiment arranged on both sides of the shaft, or a link rod in which a wedge cam pivotally supports a cam roller without using a link type booster. Or even a wedge cam that directly expands the brake arm base end.), The boost ratio in the link booster, and the structure of the automatic clearance adjustment mechanism When an excessive stroke occurs, the front end surface of the wedge cam is in contact with the rear end surface of the adjustment rod, so that there is a gap between the rear end surface of the adjustment rod and the front end surface of the wedge cam. A shim for adjusting a production error may be interposed. The material, friction coefficient, and arrangement of the friction member as a friction applying member for the sleeve member of the adjustment rod (in place of the arrangement on the inner circumference side of the sleeve member in the embodiment, arranged on the outer circumference side of the adjustment rod) The contact form between the large-diameter portion at the tip of the camshaft and the small-diameter step portion at the adjustment rod, the shape and type of the release plug, and the arrangement form on the body can be appropriately selected. In addition, the specifications described in the examples are merely examples in all respects and should not be interpreted in a limited manner.

  The automatic clearance adjustment mechanism for a wedge cam type brake according to the present invention is preferably applied to a caliper type disc brake of a railway vehicle, but can also be applied to a vehicle such as an automobile, an industrial disc brake, and the like.

4 Brake arm 10 Wedge cam 11 Camshaft 11A Tip portion 20 Stationary portion (sleeve member)
22 Adjustment rod

Claims (4)

A wedge cam type brake in which a base end portion of a brake arm is expanded and oscillated by a cam action of the wedge cam by an axial movement of a cam shaft forming a wedge cam, and the brake arm when an excessive stroke occurs in the cam shaft In the wedge cam type brake automatic gap adjustment mechanism configured to fill the rocking gap, the adjustment rod fitted to the tip of the camshaft is axially moved relative to the stationary part when the excessive stroke occurs. An automatic gap adjustment mechanism for a wedge cam type brake, wherein the initial position of the camshaft in the axial direction is changed by adjusting the relative position of the camshaft. The automatic clearance adjustment mechanism for a wedge cam type brake according to claim 1, wherein the adjustment rod is fitted to an inner periphery of a sleeve member fixed to the body via a friction member. The front end surface of the wedge cam abuts against the rear end surface of the adjustment rod when the excessive stroke occurs, and the relative position in the axial direction of the adjustment rod with respect to the sleeve member is changed. Automatic wedge adjustment mechanism for wedge cam brakes as described. 4. The axial position of the camshaft with respect to the stationary portion via the adjustment rod is reset by pressing the adjustment rod from the outside via a release plug. An automatic clearance adjustment mechanism for a wedge cam type brake according to any one of the above.

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