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WO2018172788A1 - Frein à tambour - Google Patents

Frein à tambour Download PDF

Info

Publication number
WO2018172788A1
WO2018172788A1 PCT/GB2018/050764 GB2018050764W WO2018172788A1 WO 2018172788 A1 WO2018172788 A1 WO 2018172788A1 GB 2018050764 W GB2018050764 W GB 2018050764W WO 2018172788 A1 WO2018172788 A1 WO 2018172788A1
Authority
WO
WIPO (PCT)
Prior art keywords
drum
shoes
teeth
strut
brake
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB2018/050764
Other languages
English (en)
Inventor
Russell Pike
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TRW Ltd
Original Assignee
TRW Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by TRW Ltd filed Critical TRW Ltd
Publication of WO2018172788A1 publication Critical patent/WO2018172788A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D65/00—Parts or details
    • F16D65/38—Slack adjusters
    • F16D65/40—Slack adjusters mechanical
    • F16D65/62—Slack adjusters mechanical self-acting in both directions for adjusting excessive and insufficient play
    • F16D65/64—Slack adjusters mechanical self-acting in both directions for adjusting excessive and insufficient play by means of direct linear adjustment
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D51/00—Brakes with outwardly-movable braking members co-operating with the inner surface of a drum or the like
    • F16D51/16—Brakes with outwardly-movable braking members co-operating with the inner surface of a drum or the like shaped as brake-shoes pivoted on a fixed or nearly-fixed axis
    • F16D51/18—Brakes with outwardly-movable braking members co-operating with the inner surface of a drum or the like shaped as brake-shoes pivoted on a fixed or nearly-fixed axis with two brake-shoes
    • F16D51/20—Brakes with outwardly-movable braking members co-operating with the inner surface of a drum or the like shaped as brake-shoes pivoted on a fixed or nearly-fixed axis with two brake-shoes extending in opposite directions from their pivots
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D65/00—Parts or details
    • F16D65/38—Slack adjusters
    • F16D65/40—Slack adjusters mechanical
    • F16D65/52—Slack adjusters mechanical self-acting in one direction for adjusting excessive play
    • F16D65/54—Slack adjusters mechanical self-acting in one direction for adjusting excessive play by means of direct linear adjustment
    • F16D65/546—Slack adjusters mechanical self-acting in one direction for adjusting excessive play by means of direct linear adjustment for mounting within the confines of a drum brake

Definitions

  • the present invention relates to drum brakes for vehicles.
  • Drum brakes are well known.
  • the main components of a drum brake for a vehicle are a rotating cylindrical drum and a set, usually an opposed pair, of brake shoes located in the drum.
  • the shoes are pushed into contact with the drum, so that a friction force is generated between the shoes and drum when the drum is rotating which applies a drag to slow the drum.
  • the drum is typically secured to a road wheel of the vehicle so that the drum rotates as the wheel rotates, and the shoes are fixed to a carrier or backing plate that does not rotate.
  • An actuator applies a force to each shoe to press them onto the inner face of the drum.
  • this actuator comprises a pair of opposed pistons in a common cylinder which can be pushed apart by forcing hydraulic fluid into the cylinder when braking is required.
  • An electro-mechanical actuator may be used as an alternative
  • the adjuster mechanisms in prior art drum brakes are highly robust assemblies intended to bear high loads and in many cases resist long lasting compressive loads when the drum brake includes a parking brake function. They must also overcome the force of a return spring that commonly interconnects the two brake shoes to retract the shoes when the brake is released.
  • a drum brake for a vehicle comprising:
  • an actuator mechanism which is connected at a first end to one of the brake shoes and at an opposing second end to the other of the brake shoes, operation of the brake causing the length of the actuator mechanism to increase, thereby pushing the two shoes away from each other to press the shoes onto the drum when braking is required, and
  • a self-adjuster assembly which interconnects the pair of brake shoes, the self- adjuster assembly comprising:
  • a strut having an adjustable length formed from two inter-engaging parts, and a retraction spring that interconnects the two shoes that in use forces the shoes back out of contact with the drum once the actuator mechanism is released,
  • the strut comprises a two-part latching assembly that allows extension of the strut along a linear or curvilinear path, in which a first part of the latching assembly carries a set of teeth that are resiliently engageable with a corresponding set of teeth of the second part in a plurality of different positions to define a set of discrete lengths for the strut, the first part and the second part being configured such that the strut will resist a compressive force applied by the retraction spring but are free to move apart forcing the teeth to ride over one another when the actuator moves the brake shoes by a distance that exceeds the spacing between adjacent teeth on the first part.
  • the two parts of the latching assembly may provide a resistance to relative linear movement of the two parts that will cause the teeth of the latching assembly to skip from one incremental length to the next length that exceeds the compressive force that will, in use, be applied to the strut by the retraction spring. This ensures that as the strut increases incrementally in length to take up wear the teeth prevent the strut from being compressed back by the retraction spring.
  • the two parts should provide a low enough resistance to relative movement that it can be overcome by pressure applied by the actuator mechanism during braking when the stroke of the actuator exceeds the spacing between teeth. This enables the self-adjustment on braking when wear is present, typically increasing in length by the spacing between adjacent teeth. As more wear occurs, the strut will again increase in length when the stroke exceeds the spacing between teeth.
  • One of the two parts may comprise a block having a bore which defines a plurality of inwardly facing ridges spaced along the bore, each defining a tooth of the part, and the other part may comprise a shaft having a set of circumferential ridges spaced along a length of the shaft, the shaft being located at least partially in the bore so that one or more of the ridges of the shaft engage the ridges of the bore.
  • the ridges on the bore and shaft may each define a set of triangular teeth.
  • the strut must be able to stretch slightly to permit the required movement of the shoes away from each other before it retracts as the brakes are released. This can be achieved by making the teeth suitably resilient or incorporating an element of backlash or clearance into the latching mechanism.
  • the teeth on one or both parts may be resilient.
  • the teeth may be rigid and may be supported by a resilient backing portion of each part to allow them to deflect and ride over one another as the length is adjusted.
  • the set of teeth may comprise one tooth, or two or more teeth.
  • the number and spacing of teeth will define the range of discrete lengths that the self-adjusting strut can adopt.
  • one or both of the parts of the latching mechanism may comprise plastic components.
  • the latching mechanism may be bi-directional, whereby the length of the strut can be reduced when a force is applied to the two parts that exceeds the compressive force of the retraction spring. This feature will allow the strut to be retract in length in the event that the drum brake contracts and cools following a period of braking which has generated a high heat and caused the ratchet to increase in length as a result of expansion of the drum increasing the stroke of the actuator.
  • Each end of the actuator mechanism may act on a corresponding end of each shoe, and the strut may interconnect the two shoes at those ends adjacent to the region where the actuator mechanism acts on the shoes.
  • the actuator may comprise a hydraulic actuator.
  • the actuator mechanism may comprise a pair of pistons located at opposed ends of a cylinder which receives an incompressible hydraulic fluid, pressurizing the fluid causing the pistons to move apart.
  • the actuator may comprise an electro-mechanical actuator which may comprise an electric motor in conjunction with a gear train to drive the shoes into contact with the drum.
  • Figure 1 is a view in plan of a drum brake assembly according to the present invention
  • Figure 2 is a partial cross-sectional view of the strut of Figure 1.
  • a drum brake 100 comprises a drum 102, which commonly rotates with a wheel of a vehicle (not shown), and a pair of brake shoes 104.
  • Each one of the pair of brake shoes 104 includes a friction surface 106 that, in use, contacts an inner surface 108 of the drum.
  • the friction generated by the action of the friction surface 106 rubbing against the inner surface 108 of the drum 102 converts kinetic energy of the drum 102 and wheel to heat energy, slowing the rotation of the drum 102 in relation to the brake shoes 104.
  • Each brake shoe 104 is attached to a backing plate 1 10 of the drum brake 100 by a hold-down pin 1 12 and spring 1 14.
  • a cylinder 1 16 is provided, operating as an actuator mechanism.
  • the cylinder 1 16 is connected to a hydraulic braking circuit of a vehicle (not shown). Pressure build-up in the cylinder 1 16, caused by compression of a foot brake or otherwise, results in the expansion of the cylinder 1 16.
  • Each brake shoe 104 is pivoted at one end about an anchor point 1 18 formed on an anchor block 120. The anchor block 120 is not fixed, allowing the brake shoes 104 to self-centre when in operation. The other end of each brake shoe 104 is attached to the cylinder 1 16.
  • each brake shoe 104 attached to the cylinder 1 16 moves further apart, causing pivoting of each brake shoe 104 about its anchor point 1 18 and thus forcing the friction surfaces 106 into contact with the drum 102.
  • a retraction spring 122 acts between the brake shoes 104 in order to provide a return force that brings the brake shoes 104 back to a rest position once the pressure in the cylinder 1 16 decreases.
  • a strut 124 is positioned between the two brake shoes 104, the strut 124 preventing the retraction spring 122 from pulling the brake shoes 104 further together than a distance set by the length of the strut 124.
  • the strut 124 comprises two parts 126, 128 that inter-engage using a plurality of teeth 130.
  • each part 126, 128 has a large number of teeth 130, for example ten, but it may be possible to provide one of the parts 126, 128 with a single tooth 130 and the other part 126, 128 with a plurality of teeth 130, as long as the strut 124 is capable of withstanding the forces applied by the retraction spring 122.
  • the movement of the two parts 126, 128 therefore results in the strut 124 adopting one of a set of discrete positions resulting in it having one of a set of discrete lengths, each length corresponding to a different positional relationship between the teeth 130 of the parts 126, 128.
  • the first part 126 includes a plurality of teeth 130 on the outside of a shaft 132, the second part 128 having a plurality of teeth 130 within a bore formed in a block, thus forming a sleeve 134, the shaft 132 of the first part 126 being received within the sleeve 134 of the second part 128.
  • the teeth 130 may also be considered to be ridges formed circumferentially around the shaft 132 and bore.
  • Resilient engagement of the teeth 130 of the two parts 126, 128 is provided in the present example by resilient deformation of the teeth 130. That is, under load, the respective teeth 130 deform to an extent that one set of teeth 130 is forced to ride over the other.
  • the resilient engagement in other ways.
  • the resilience required to allow the teeth to be forced over one another, whilst still ensuring engagement when under lower loads may be provided by additional components such as an elastic member that provides compression of the two sets of teeth towards each other.
  • the compression of the elastic member must be selected carefully in order that the engagement or meshing of the teeth is overcome only under loads greater than those under which the strut is designed to remain rigid.
  • substantially rigid teeth on either or both of the first and second parts may be supported by a layer that gives a degree of resilience.
  • a rubberised or resilient polymer layer may allow the teeth of the first part and second part to move away from each other under sufficient load.
  • the teeth 130 do not engage fully but instead some level of relative movement of the teeth 130 is allowed by the provision of a backlash or clearance between the sets of teeth 130.
  • the size of the clearance determines the amount of wear of the brake shoes 104 or the amount of expansion of the drum 102 that must occur before the strut 124 adjusts by the sets of teeth 130 riding over one another.
  • the teeth 130 may ride over one another in the opposite direction.
  • the expansion and contraction of the drum 102 may be due to temperature fluctuations in the environment or temperatures produced during operation of the brakes, for example.
  • the strut 124 of the depicted embodiment is linear, it is also possible to provide a non-linear strut such as a curvilinear strut, whereby the strut follows a curved path. Use of such a design may be necessitated or desired due to the shape or placement of other parts of the drum brake 100, for instance.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Braking Arrangements (AREA)

Abstract

L'invention concerne un frein à tambour pour un véhicule, le frein comprenant un tambour, une paire de patins de frein situés à l'intérieur du tambour, chacun faisant face à un revêtement interne du tambour, un mécanisme actionneur relié au niveau d'une première extrémité à l'un des patins de frein et au niveau d'une seconde extrémité opposée à l'autre patin de frein, le fonctionnement du frein provoquant l'augmentation de la longueur du mécanisme actionneur et poussant ainsi les deux patins à l'opposé l'un de l'autre afin de presser les patins sur le tambour lorsqu'un freinage est nécessaire, et un ensemble de réglage automatique reliant ensemble la paire de patins de frein. L'ensemble de réglage automatique comprend une entretoise présentant une longueur réglable et formée de deux parties en prise l'une avec l'autre, et un ressort de rappel destiné à interrelier les deux patins, ce qui force les patins, lors de l'utilisation, à se retirer du contact avec le tambour une fois que le mécanisme actionneur est relâché. L'entretoise comprend un ensemble de verrouillage en deux parties permettant l'extension de l'entretoise le long d'un trajet linéaire ou curviligne, la première partie de l'ensemble de verrouillage portant un jeu de dents pouvant s'engrener de manière élastique avec un jeu correspondant de dents élastiques de la seconde partie dans une pluralité de positions différentes, afin de définir une série de longueurs distinctes pour l'entretoise.
PCT/GB2018/050764 2017-03-24 2018-03-23 Frein à tambour Ceased WO2018172788A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB1704703.6 2017-03-24
GB1704703.6A GB2560755B (en) 2017-03-24 2017-03-24 Drum brake

Publications (1)

Publication Number Publication Date
WO2018172788A1 true WO2018172788A1 (fr) 2018-09-27

Family

ID=58688068

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2018/050764 Ceased WO2018172788A1 (fr) 2017-03-24 2018-03-23 Frein à tambour

Country Status (2)

Country Link
GB (1) GB2560755B (fr)
WO (1) WO2018172788A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111577792A (zh) * 2020-06-08 2020-08-25 唐泽交通器材(泰州)有限公司 一种耐磨性能好的鼓式制动器
CN116928250A (zh) * 2023-09-06 2023-10-24 浙江新中南汽车零部件股份有限公司 一种刹车间隙自动调整臂预设间隙调节装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR666390A (fr) * 1928-03-08 1929-10-01 Teves Kg Alfred Butée pour freins
GB1072493A (en) * 1964-05-02 1967-06-14 Daimler Benz Ag Improvements relating to disc brakes
FR2514846A1 (fr) * 1981-10-16 1983-04-22 Automotive Prod Plc Dispositif automatique de rattrapage de jeu pour frein a tambour
DE3925869A1 (de) * 1989-01-12 1991-02-07 Teves Gmbh Alfred Nachstellvorrichtung fuer eine trommelbremse

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1825555A (en) * 1927-11-02 1931-09-29 Teves Kg Alfred Brake
GB963100A (en) * 1962-04-13 1964-07-08 Perrot Bremse Gmbh Deutsche A hydraulic internal shoe-drum brake
GB2004606B (en) * 1977-09-20 1982-01-13 Automotive Prod Co Ltd Internal shoe drum brakes
GB2233409B (en) * 1989-06-24 1993-06-30 Teves Gmbh Alfred Automatic adjusting apparatus for a duo-servo drum brake
GB2234564B (en) * 1989-08-04 1993-07-21 Teves Gmbh Alfred Adjusting device for a drum brake.
GB0621497D0 (en) * 2006-10-25 2006-12-06 Automotive Prod Italia Sv Srl Drum brakes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR666390A (fr) * 1928-03-08 1929-10-01 Teves Kg Alfred Butée pour freins
GB1072493A (en) * 1964-05-02 1967-06-14 Daimler Benz Ag Improvements relating to disc brakes
FR2514846A1 (fr) * 1981-10-16 1983-04-22 Automotive Prod Plc Dispositif automatique de rattrapage de jeu pour frein a tambour
DE3925869A1 (de) * 1989-01-12 1991-02-07 Teves Gmbh Alfred Nachstellvorrichtung fuer eine trommelbremse

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111577792A (zh) * 2020-06-08 2020-08-25 唐泽交通器材(泰州)有限公司 一种耐磨性能好的鼓式制动器
CN116928250A (zh) * 2023-09-06 2023-10-24 浙江新中南汽车零部件股份有限公司 一种刹车间隙自动调整臂预设间隙调节装置
CN116928250B (zh) * 2023-09-06 2024-05-03 浙江新中南汽车零部件股份有限公司 一种刹车间隙自动调整臂预设间隙调节装置

Also Published As

Publication number Publication date
GB2560755B (en) 2022-09-14
GB2560755A (en) 2018-09-26
GB201704703D0 (en) 2017-05-10

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