Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T11/00—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant
  • B60T11/10—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting by fluid means, e.g. hydraulic
  • B60T11/16—Master control, e.g. master cylinders
  • B60T11/20—Tandem, side-by-side, or other multiple master cylinder units
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T11/00—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant
  • B60T11/10—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting by fluid means, e.g. hydraulic
  • B60T11/16—Master control, e.g. master cylinders
  • B60T11/224—Master control, e.g. master cylinders with pressure-varying means, e.g. with two stage operation provided by use of different piston diameters including continuous variation from one diameter to another

Definitions

• Valve brake control device for a motor vehicle
• the invention relates to braking circuits for a motor vehicle with a brake fluid reservoir and a master cylinder. It is known that, in a conventional braking circuit for a vehicle, the brakes receive the braking command in the form of a pressure of brake fluid coming from a master cylinder, itself supplied from a reservoir of liquid.
• the braking command issued by the driver in mechanical form is converted into hydraulic form by the master cylinder by means of two pistons movable in the body of the master cylinder.
• the chamber intended to be compressed by each piston is in communication with the liquid reservoir through an orifice of the piston. When the piston movement begins, this orifice crosses a sealing lip so that the chamber is isolated from the reservoir and the pressure in the chamber can start to rise.
• the stroke of the piston until the start of pressure growth is called the "dead stroke" because it does not contribute to braking. We therefore seek to reduce this race as much as possible.
• An object of the invention is to reduce the dead stroke without risking the valve breaking in the presence of an ABS type device.
• a brake control device comprising:
• valve capable of authorizing a rise in the liquid from the cylinder in the reservoir by presenting a first minimum flow section, the valve being capable of authorizing the rise by presenting a second minimum flow section larger than the first section when a pressure in the cylinder exceeds a predetermined threshold.
• the valve continues to behave essentially as a shutter when the piston starts its stroke, the pressure then being relatively reduced and below the threshold.
• the second section allows the liquid to rise towards the tank without risk of damaging the valve. This preserves both the integrity of the valve and the short length of the dead stroke.
• the device according to the invention may also have at least any of the following characteristics:
• the valve comprises a seat and a shutter capable of coming to bear against the seat
• the shutter comprises means for centering the shutter relative to the seat, - the shutter has a density less than that of the liquid, - the seat is rigid,
• the seat is capable of being moved relative to the tank when the pressure exceeds the threshold
• the seat has at least one duct and is arranged to allow the liquid to rise through the duct only when the displacement of the seat occurs,
• the seat is capable of being elastically deformed when the pressure exceeds the threshold, the seat is deformable so that the liquid bypasses or passes through the seat during the rise;
• the seat has at least one orifice designed to be opened only during the deformation
• the orifice opens at one edge of the seat, the orifice extends at a distance from the edges of the seat,
• the shutter has at least one duct and is arranged to allow the liquid to rise through the duct when the shutter is in contact with the seat,
• the duct extends over one face of the shutter capable of coming into contact with the seat
• the shutter has a substantially spherical face capable of coming into contact with the seat
• the shutter is a ball
• the shutter has a general shape of cake
• the valve has an outlet for the liquid to the master cylinder arranged so that the shutter, in its lowest position, leaves this opening open, - the opening extends in a vertical wall, it includes means for retaining the shutter relative to the reservoir before assembly of the reservoir to the master cylinder, and
• the valve is capable of authorizing a descent of the liquid from the reservoir into the master cylinder by having a third minimum flow section larger than the first section.
• a valve is also provided for a brake control device with a liquid reservoir and a master cylinder, the valve being able to authorize a rise in liquid by presenting a first minimum flow section, and to authorize the rise. by presenting a second minimum flow section larger than the first section when a liquid pressure reaches a predetermined threshold upstream of the valve, with reference to the direction of flow during the rise.
• FIG. 1 is a partial view of an embodiment of the device according to the invention showing the reservoir schematically, the valve and a part of the master cylinder in axial section;
• FIGS 2, 3 and 4 are three views in axial section of the valve of the device of Figure 1 showing three respective operating phases;
• FIG. 5 is a sectional view of the valve seat along the plane V-V of Figure 4;
• FIG. 6 is a view similar to Figure 2 showing another embodiment
• - Figures 7, 8 and 9 are three views in axial section similar to Figure 2 showing three other embodiments;
• - Figures 10, 11 and 12 are three views in axial section respectively similar to Figures 2 to 4 and illustrating another embodiment of the invention
• - Figures 13 to 15 are three perspective views, and in addition in section for Figure 13, illustrating different alternative embodiments of the shutter in the valve of Figure 10;
• FIG. 16 is an axial view similar to Figure 10 showing another alternative embodiment
• Figure 17 is a view similar to Figure 10 showing an alternative embodiment of the shutter seat, alone, at rest;
• - Figure 18 is a view of the seat of Figure 17 with the shutter in the case where the pressure exceeds the predetermined threshold;
• - Figures 19 to 20 are views similar to Figures 17 and 18 and illustrating another embodiment of the seat;
• FIG. 21 is an exploded perspective view of some parts of the valve of another embodiment of the invention.
• FIG. 22 and 23 are two views in axial section of the valve of Figure 21 in two different states.
• FIG. 24 is an axial sectional view of another embodiment of the valve according to the invention.
• This device is intended for a motor vehicle comprising a hydraulic braking circuit supplying brake fluid under pressure to the disc or drum brakes associated respectively with the four wheels of the vehicle.
• the device comprises a master cylinder 2, here of the tandem type, comprising two pistons of which only one 4 has been illustrated, capable of generating an increase in pressure in the circuit for transmitting a command to the brakes. braking from the driver.
• the device also includes a brake fluid reservoir 4 6 arranged to supply brake fluid to each of the two chambers 8 associated with the respective pistons 4.
• a single supply circuit has been illustrated in FIG. 1, but it is understood that the device like the devices of the prior art comprises two circuits making it possible to supply each of the chambers 8 with liquid from the same reservoir 4.
• the reservoir 4 is arranged above the master cylinder so as to promote the gravity flow of the liquid from the reservoir to the master cylinder.
• the tank is mounted by fitting into the master cylinder.
• the reservoir 4 has a cylindrical neck 10 capable of being received in a male-female engagement in a cylindrical housing 12 of the master cylinder of corresponding size.
• the device according to the invention comprises a valve 14 disposed in a cavity of the master cylinder extending immediately under the neck 10 of the tank.
• the valve can therefore receive liquid directly from the reservoir.
• a conduit 16 puts the valve in direct communication with the piston chamber or with the piston itself depending on the position of the latter.
• the device comprises a seal 20 interposed between the neck 10 and the housing 12 so as to seal against the liquid at the junction thereof and consequently isolate the valve from the atmospheric air.
• the device according to the invention will preferably comprise two valves as mentioned above. It is of course conceivable that the master cylinder shown has a single valve, advantageously disposed in the secondary circuit as shown in the figure.
• the neck 10 has a lip 22 extending radially inward of the neck with reference to a vertical central axis 11 thereof. This lip 22 is continuous all around the axis.
• the valve has a seat 24 illustrated in particular in Figure 5.
• This seat includes a washer 26 having in its center an orifice 28 and extended radially from its outer circumference by tongues 30 here four in number uniformly distributed around the washer .
• the orifice has a circular shape interrupted by a leakage channel such as a notch for the passage of the liquid.
• the seat 24 rests on the lip 22. In this position, the ends of the tongues 30 provide a sliding support against the internal face of the neck 10, which ensures a substantially coaxial centering of the washer relative to the neck.
• the outside diameter of the washer 26 is greater than the inside diameter of the lip 22 so that the outside edge of the washer is in continuous support on the lip 22.
• the shutter 14 comprises a spiral spring 32 of generally conical shape bearing downwards at the point of its narrowest section on the upper face of the washer 26, while it is bearing upwards against a shoulder 34 formed for this purpose in the neck 10. This spring 32 ensures a return of the seat 24 downwards against the lip 22.
• the valve comprises a shutter 40 constituted in this case by a ball.
• This ball is made of a material known per se so as to have a density lower than that of the liquid. In this way, the ball when it is immersed in the liquid tends to rise up against gravity.
• the ball extends under the seat 24 opposite the lip 22. It is placed at rest in abutment against the washer 26 while roughly closing off the central orifice 28 thereof.
• This device works as follows. With reference to FIG. 2, the liquid present in the master cylinder can freely rise at low pressure in the direction of the reservoir by crossing the conduit 16 then the neck 10 while fleeing through the notch of the orifice 8 between the shutter 40 and the seat 24 as indicated by the arrow 25. Furthermore, if necessary, the liquid present in the reservoir can flow through the conduit 16 in the direction of the master cylinder. This flow momentarily lowers the ball away from the seat 24 to provide a large passage section for the liquid.
• FIG. 4 illustrates the case where for any reason, for example due to the sending of brake fluid into the master cylinder by an ABS type device, the pressure in the master cylinder increases suddenly for example while that -this is at rest. This pressure is therefore transmitted to the valve 14. This high pressure urges the ball 40 and the seat 24 against the spring 32 so that the spring is compressed and the seat and the shutter are raised in one piece. Under these conditions, a large passage section is available for the liquid on the one hand between the shutter 40 and the lip 22 and on the other hand between the tongues 30.
• the smallest flow section 31 which we will call here first minimum section is defined between the shutter 40 and the seat 24 by the notch of the orifice 28.
• the smallest flow section 33 which we will call the second minimum section is defined between the shutter 40 and the lip 22 and between the tongues 30. This second minimum section 33 is larger than the first minimum section 31.
• the configuration of the device determines a threshold such that, when the pressure is below this threshold, the liquid rise ' occurs in the configuration of Figure 2 while when this pressure exceeds the threshold this rise takes place according to the configuration in Figure 4. This threshold largely depends on the load of the spring 32. It will be easy to configure the device and in particular to calibrate the spring to adjust the predetermined pressure threshold at the va their desired.
• the flow of the liquid occurs through a minimum section 35 which we will call here third minimum section which is defined by the orifice 28 of the seat. This section 35 is larger than the first section 31 associated with FIG. 2.
• valve may include a screen or a filter 42 extending downward from the lip 22 and enclosing the shutter 40 while being at a distance from the conduit 16.
• a screen or a filter 42 extending downward from the lip 22 and enclosing the shutter 40 while being at a distance from the conduit 16.
• FIG. 6 An alternative embodiment of the device has been illustrated in FIG. 6 with certain numerical references increased by 100.
• the shutter 140 is this time configured in the form of a disc having on its upper face a shoulder or a channel entering this face approximately over 90 or 180 °.
• the diameter of the shutter 140 is greater than the diameter of the central orifice 28 of the seat 24.
• the shutter 140 extends in support from below against the seat 24. Knowing that the orifice 28 of the seat is not completely closed off by the shouldered upper face, an ascent of liquid at low pressure remains possible at all times, the liquid passing between the shutter and the seat at the level of the shoulder. When the pressure exceeds the predetermined threshold, the seat and the shutter moving upward compress the spring 32 to provide a larger flow section. If the liquid is lowered from the reservoir to the master cylinder, the shutter 140 can be lowered to allow the liquid to flow through the orifice 28 with a larger section than in the case of the rise to low pressure.
• FIG. 7 Another embodiment has been illustrated in FIG. 7.
• the neck 10 of the reservoir is fitted into the housing 12 of the master cylinder with the interposition of a seal. 20 although the transverse profile of the latter differs here from that of FIG. 2.
• the profile of the joint has here two lateral bulges one above the other.
• the seat 224 in this case has a generally cylindrical shape with an axis 11. It comprises a lip 225 extending radially outward with reference to the axis 11.
• the neck 10 comprises meanwhile a lip 13 s' radially extending 'inwardly by reference to the axis 11 in the upper part of the neck.
• the spring 232 here has a generally cylindrical shape with an axis 11 and bears upwards against the lower face of the lip 13 and downwards against the upper face of the lip 225. It therefore again contributes to stressing the seat 224 down.
• An O-ring seal 44 is interposed radially with reference to the axis 11 between the neck 10 and the seat 224, this seal extending below the lip 225.
• the seat 224 has a lower axial end edge 246 essentially plan extending, when the valve 240 is at rest, lower than the lower edge of the neck 10.
• the shutter 240 in this case has the general shape of a wafer or a disc. It has, for example in its center, a duct 228 of cylindrical shape passing through the shutter according to its thickness.
• the shutter also has at least one notch 248 entering the outer edge of the shutter.
• this pressure biases upward the shutter 240, which causes the shutter to rise in one piece with the seat 224 until the shutter 240 rests against the edge lower 246 of the col.
• the still high pressure is communicated through the notch 248 to the underside of the seal 244 which is therefore biased upwards.
• the seal 244 moves upwards by compressing the spring 232.
• the space thus created between the lower edge 246 of the seat and the shutter 240 which remains lower then offers a large section for the passage of the liquid to high pressure.
• a flow of liquid can occur from the reservoir to the master cylinder which causes a temporary descent of the shutter 240 away from the lower edge 246 of the neck.
• FIG. 8 Another embodiment is illustrated in FIG. 8.
• the shutter 340 is here again formed by a washer crossed here in its center by a conduit 228.
• the notch of the previous mode is this time omitted.
• This shutter is also illustrated in FIG. 13.
• the seat 324 is here formed by a seal interposed radially by reference to the axis 11 between the neck 10 and the housing 12.
• the lower edge 346 of the neck 10 which s extends opposite the shutter 340 has at least one notch 348 on one side.
• the joint 324 has a profile with two overlapping bulges as in the previous mode. Its lower end has an essentially rectangular profile. It is in abutment from above against a shoulder of the neck 10 and from below against the upper face of the shutter 340.
• the seal is also in tight contact in the radial direction at the level of the lower bulge at least with the neck 10 and the housing 12.
• the seat 324 keeps the shutter 340 away from the lower edge 346 of the neck 10.
• the liquid is lowered from the reservoir to the master cylinder as before by temporarily lowering the shutter 340.
• FIG. 9 Another embodiment is illustrated in FIG. 9. It is very close to the previous one, the upper part of the seal 424 being this time replaced by a return spring 432 bearing against the seal 424 downwards and against a shoulder of the neck. to the top. The operation is substantially unchanged.
• FIG. 10 to 13 Another embodiment is illustrated in Figures 10 to 13.
• the shutter 340 is again configured as a disc pierced here in its center by an orifice 228.
• the seat 524 provides the seal between the neck 10 and the housing 12.
• this seal has an O-ring upper part 550 ensuring the seal between these two parts radially by reference to the axis of the valve.
• the seal also has a lower skirt 553 of cylindrical shape extending downwards from the upper toric part 550. It is against the lower edge of this skirt that the shutter 340 is applied.
• the upper toric part 550 is housed in a shoulder of the neck 10 internally covering this part as far as the skirt 553.
• the skirt has slots 552 uniformly distributed around the axis and each extending vertically over the greater part of the height of the skirt while remaining at a distance from its edges. These slots radially pass through the thickness of the skirt.
• the orifice 16 making the valve communicate with the master cylinder is this time formed in a side wall of the master cylinder and not vertical to the shutter 340.
• This orifice 16 has a diameter greater than the height of the shutter 340. Under these conditions, no position of the shutter 340 does not allow it to close the orifice 16. This arrangement is also advantageous if necessary for the other embodiments.
• FIG. 14 illustrates an alternative embodiment of the shutter.
• the shutter 640 can be used with the valve of FIG. 10.
• the duct is here replaced by a groove 628 extending on the upper face of the shutter and starting the latter from at least one circumferential edge.
• the groove 628 extends uninterruptedly, along a diameter of this face from one edge to the other of this face.
• This groove 628 allows the flow of the liquid for its ascent into the reservoir at low pressure, the groove not being closed by pressing the upper face of the shutter against the lower edge of the seat 524.
• Another embodiment of the shutter 740 is illustrated in Figure 15. In this case the groove 728 is made in two parts.
• each groove part extends from an edge of the shutter towards the center of the latter over a length sufficient to allow the groove part to open out in the center of the seat.
• the shutter 740 has a central relief 760 extending projecting from its upper face and having for example a portion shape. sphere or an approximate shape.
• This relief 760 is housed in the center of the seat and thus ensures centering of the shutter relative to the seat and on the other side a stroke limitation.
• the shutter comprises a relief 760 and a groove 728 in two parts on each of these two main faces so that it is symmetrical along its horizontal median plane, which allows the shutter to be mounted in the valve without have to worry about the mounting direction.
• the reliefs 760 contribute to the centering of the shutter relative to the seat and to the limitation of the downward travel of the shutter, the lower relief shortening this travel in abutment against the bottom of the housing of the master cylinder. Finally, they contribute by increasing the volume of the part to favor the buoyancy and therefore increase the natural rise of the shutter in the liquid.
• FIG. 16 shows another embodiment in which the seat 524 of FIG. 10 has been separated into two distinct parts, the cylindrical skirt alone forming this time the seat 824 while the O-ring 850 seals between the neck 10 and housing 12.
• Figures 17 to 18 show another embodiment in which the slots of Figure 11 are replaced by slots which open into the lower axial end edge of the seat 524. These slots cut the skirt into several separate tabs able to bend independently of each other in the case where the pressure of the liquid exceeds the predetermined threshold. The liquid then flows between these tabs.
• FIGs 19 and 20 show an embodiment in which the shutter
• the 1024 has no slits or orifices. This time when the liquid rises with a pressure greater than the predetermined threshold, the liquid causes the seat to deform by bending it inwards and flows bypassing the seat parts thus deformed, passing between the seat and the shutter.
• FIG. 21 to 23 Another embodiment is illustrated in Figures 21 to 23.
• the seat and the shutter are essentially unchanged compared to the embodiment of Figures 19 and 20.
• the neck 10 this time has two reliefs in the form of fingers 1064 s' extend downward from the bottom axial end edge 1046 of col. These two fingers are preferably arranged asymmetrically with respect to the axis 11 of the neck.
• FIG. 22 illustrates these various elements when the valve is at rest.
• the lower edge of the seat 1024 extends in this situation lower than the fingers 1064.
• Figure 23 illustrates the case where the pressure in the cylinder exceeds the predetermined threshold, thereby causing the deformation of the seat 1024 as in the modes of previous achievements.
• this deformation due to the reduction in height of the seat puts the shutter in contact with the fingers 1064 and taking into account the asymmetrical position of these causes the shutter to tilt relative to the neck, which accentuates the deformation of the seat on one side of it.
• a large flow section is then formed between the seat and the shutter for the ascent of the liquid.
• Figure 24 illustrates an embodiment similar to that of Figures 21 to 23, more clearly illustrating the asymmetrical position of the two fingers relative to the axis of the neck.
• the shutter 1040 is here extended upward by a rod 1068 fixed to the center of the upper face of the shutter and extending coaxially in the neck 10.
• This rod carries at its upper end a pair of lugs 1070 oriented downwards by being inclined relative to the rod so as to be able to bear against an upper shoulder 1072 of the neck and thereby limit the fall of the shutter.
• This embodiment has the advantage that the shutter 1040 is carried captively by the neck of the reservoir until the reservoir and the master cylinder are assembled.
• the lugs 1070 also help limit the downward travel of the shutter relative to the seat. Under these conditions, it is again possible to open the conduit 16 in the bottom of the housing 12 without risking it being blocked by the shutter.
• the seals may be made of elastomer. It may be the same for each seat able to deform when the pressure exceeds the threshold, especially when this seat is also as a seal. This will therefore be the case for elements 20, 24, 244, 324, 424, 524, 824, 850, 924 and 1024.
• the shutters may each time be made of a material less dense than the liquid so as to rise naturally in support. against the seat.
• the wall of the reservoir, in particular the neck may be made of plastic.
• the wall of the master cylinder, in particular the housing 12 may be made of metal or other material.
• the valve allows the free flow of the liquid from the reservoir to the master cylinder to supply the latter if necessary. It also allows a moderate rise of liquid at low pressure from the master cylinder to the tank. In addition, when the pressure in the master cylinder exceeds the threshold, the valve allows the liquid to rise to the reservoir without risking a rupture of the valve under the effect of the pressure.
• the assembly according to the invention can therefore safely support the sudden increases in pressure generated in the master cylinder by devices such as so-called ESP systems.
• the assembly according to the invention makes it possible to maintain a very reduced dead stroke for the piston of the master cylinder in order to guarantee rapid transmission of the brake control.
• the pressures generated in the master cylinder by ESP type devices can be a maximum of 250 10 5 Pa
• the predetermined pressure can be adjusted to a level situated for example between 5 and 10 10 5 Pa.
• piston constitute a first pressure drop between the master cylinder chamber and valve).
• the conduit is not necessarily at the center of the shutter.
• the device shown in Figure 1 comprises a master cylinder called "expansion hole”.
• a master cylinder called “valve”
• the isolation of the chamber 8 from the tank is by a valve provided with a shutter and a valve seat formed by the piston 4, the valve closing a passage made in the piston 4 allowing the communication between the reservoir and the chamber 8 at rest.

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• Engineering & Computer Science (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Transmission Of Braking Force In Braking Systems (AREA)
• Regulating Braking Force (AREA)

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• 2001
  • 2001-08-08 FR FR0110680A patent/FR2828463B1/fr not_active Expired - Fee Related
• 2002
  • 2002-08-02 US US10/486,433 patent/US20050006190A1/en not_active Abandoned
  • 2002-08-06 RU RU2004106782/11A patent/RU2004106782A/ru not_active Application Discontinuation
  • 2002-08-06 CN CNA028192729A patent/CN1561299A/zh active Pending
  • 2002-08-06 PL PL02373730A patent/PL373730A1/xx unknown
  • 2002-08-06 EP EP02772486A patent/EP1420989A1/de not_active Withdrawn
  • 2002-08-06 JP JP2003518887A patent/JP2004537465A/ja not_active Withdrawn
  • 2002-08-06 WO PCT/FR2002/002806 patent/WO2003013923A1/fr not_active Application Discontinuation
  • 2002-08-06 KR KR10-2004-7001919A patent/KR20040018553A/ko not_active Application Discontinuation

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