WO1992016767A1

WO1992016767A1 - Hydraulic brake system for vehicles

Info

Publication number: WO1992016767A1
Application number: PCT/US1992/002270
Authority: WO
Inventors: Nicolas Pecoraro Cayetano
Original assignee: Skorodoff, Ivan; Ovchinikov, Nicolas
Priority date: 1991-03-20
Filing date: 1992-03-19
Publication date: 1992-10-01

Abstract

A brake system is shown and described wherein braking forces are applied to a vehicle by coupling the vehicle wheels to a hydraulic pump (14) and thereby moving fluid within a pathway (16) in response to movement of the wheels. By restricting the flow of fluid in the pathway, rotational movement of the wheels, and therefore rectilinear movement of the vehicle, is impeded. In this manner, the brake system controls the velocity of a vehicle. The invention is shown as applied within the drive train (100) of a motorized vehicle and to the axle of a non-motorized trailer vehicle.

Description

HYDRAULIC BRAKE SYSTEM FOR VEHICLES

BACKGROUND OF THE INVENTION

The present invention relates generally to brake systems, and particularly to auxiliary brake systems for alleviating wear and stress on a primary brake system.

Brake systems play perhaps the most important role in the operation of vehicles, and must reliably perform that operation before the vehicle can be considered useful in any manner. Brake systems play a particularly important role in heavy vehicles such as semi-trucks and in trailers carrying heavy loads. If such brake systems are applied for long periods of time, the brakes overheat and lose efficiency, sometimes to the point of total destruction and even vehicle fire. In some vehicles, motor compression may be used as a brake impeding the movement of the vehicle and reducing wear and stress on the primary brake system, but such compression braking tends to deteriorate essential parts of the vehicle.

Accordingly, it is desirable that a brake system for a vehicle, especially heavy duty vehicles such as semi-trucks and trailers carrying heavy loads, be efficient with respect to braking functions and preserve the reliability of the braking system. The braking system of the present invention addresses such deficiencies in a vehicle braking system.

SUMMARY OF THE INVENTION The brake system of the present invention provides a brake function by moving hydraulic fluid as a function of vehicle movement and controlling the hydraulic fluid velocity in order to impede the movement of a vehicle. In accordance with the preferred embodiment of the present invention, the brake system includes a mechanical coupling to a ground contacting wheel of the vehicle in such manner that rotational movement of the wheel invokes corresponding movement of the coupling. Resistive forces applied to the coupling thereby impede rotation of the wheel. A hydraulic pump responds to movement of the coupling by forcibly moving a body of hydraulic fluid along a fluid path. A controllable flow restriction device along the fluid path operates to either allow substantially unencumbered flow of the fluid along the path, or apply some magnitude of resistance to flow of the fluid along the fluid path. The fluid path may be a fluid circuit wherein the hydraulic fluid circulates through the system, and the system may further include some mechanism for radiating heat energy of the fluid.

Because the velocity control is by way of impeding the movement of hydraulic fluid, the system does not apply a braking force to a vehicle while the vehicle is at rest. The braking function provided by the present invention applies directly to the velocity of the vehicle and provides a slow controlled decrease in velocity without impacting significantly the rest of the vehicle structure. Because the brake system of the present invention aides in impeding the motion of the vehicle, the present invention is usefully applied as an auxiliary brake system whereby the primary brake system, as assisted by the hydraulic brake of the present invention, can apply a reduced braking force and thereby remain cool and efficient.

According to one embodiment of the invention, the auxiliary brake system may be applied to the universal joint shaft, i.e., drive shaft, of trucks to obtain an automatic velocity control under the present invention. In a second embodiment of the invention, the auxiliary brake system is applied to the axles of a trailer to impede rotational movement of the axles, and thereby impede movement of the trailer.

The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method or operation of the invention, together with further advantages and objects thereof, may best be understood by reference to the following descriptions taken with the accompanying drawings wherein like reference characters refer to like elements. BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:

FIG. 1 illustrates schematically a hydraulic brake system according to a preferred embodiment of the present invention for motorized vehicles.

FIG. 2 illustrates use of the brake system of FIG. 1 in a motorized vehicle.

FIG. 3 illustrates schematically a second hydraulic brake system according to the present invention for trailer vehicles.

FIG. 4 illustrates use of the brake system of FIG. 3 in a trailer vehicle.

FIGS. 5 and 6 illustrate cooling apparatus for the hydraulic brakes of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates schematically a hydraulic brake 10 having a body 12 including a pump 14, hydraulic fluid pathway 16, a lock valve 18 lying along the pathway 16 and a relief valve 20. The pump 14 resides within the body 12 of brake 10 and in such relation to forcibly circulate hydraulic fluid along the pathway 16. A torque axle 30, shown schematically in FIG. 1, passes through brake 10 and includes torque transferring connections 32 at each end. In use, one connection 32 couples to the output of the transmission and the other connection 32 couples to the input of the differential in such manner that torque provided by the transmission is delivered directly via axle 30 to the differential. The axle 30 is rotationally mounted by bearing mounts (not shown) to the body 12 of brake 10. The mounting arrangements 22 of body 12 allow attachment of brake 10 to the frame of a vehicle. The brake 10 thereby becomes a torque transferring bridge of the drive train transferring torque along axle 30 from the transmission to the differential.

The pump 14 includes a pump gear 40 fixedly attached to the axle 30 for rotation according to rotation of the axle 30. A floating gear 42 of pump 14 is rotationally mounted to the body 12 of brake 10 and engages the gear 40 for rotation according to rotation of gear 40. The gears 40 and 42 occupy a chamber 44 having openings on opposite sides of the meshed arrangement of gears 40 and 42. The fluid pathway 16 couples the openings of the chamber 14 in such manner that rotation of the axle 30 results in flow of hydraulic fluid along pathway 16 from one end of pathway 16 and through chamber 44 by way of gears 40 and 42, and then re-enters at the opposite end of fluid pathway 16.

For counterclockwise rotation of the gear 40, in the view of FIG. 1, as indicated at reference numeral 50, the gear 42 moves in clockwise motion as indicated at reference numeral 52. Hydraulic fluid entering the opening 54 of chamber 44 is drawn past the gears 40 and 42. In particular, a circumferential portion of each gear 40 and 42 is adjacent a corresponding wall 58 of chamber 44. The hydraulic fluid entering chamber 44 then follows the paths 60 and 62 along the gears 40 and 42, respectively, and the corresponding sidewalls 58. As may be appreciated, the gears 40 and 42 should be in such sealing relation to the chamber 44 so as not to allow passage of hydraulic fluid through the chamber 44 in the absence of rotation of gears 40 and 42. The paths 60 and 62 then converge at the other opening 56 of chamber 44. Thus, upon rotation of the axle 30, the pump gear 40 turns and urges the floating gear 42 into rotation.

The lock valve 18 lies along the fluid pathway 16 and may be moved by movement of a lever 70 between positions 70a and 70b to provide a substantially unencumbered flow or a restricted flow, respectively, of hydraulic fluid in pathway 16. Intermediate positions of lever 70, i.e., between those illustrated at 70a and 70b, would provide varying magnitudes of resistance to flow of hydraulic fluid in pathway 16. As may be appreciated, the lever 70 may be operated remotely by a conventional mechanical coupling arrangement (not shown) . The relief valve 20 provides a pathway around lock valve 18 in the event of unacceptably high hydraulic pressure within the brake 10.

A sealable filling orifice 74 allows introduction of hydraulic fluid into the system of pathway 16 and pump 14.

The resistance to flow of hydraulic fluid in the pathway 16 provided by the lock valve 18 impedes the movement of the vehicle by virtue of the direct coupling of axle 30 to the drive train of the vehicle and the forced movement of hydraulic fluid through pump 14 that results from rotation of the axle 30. To the extent that the lock valve 18 restricts fluid flow, it similarly restricts the movement of the vehicle in a desirable controlled decrease in velocity.

FIG. 2 is a schematic illustration of the use of hydraulic brake 10 within the drive train 100 of a vehicle 102. In FIG. 2, the brake 10 mounts at mounting arrangements 22 to the frame 104 of vehicle 102. The torque axle 30 couples to the output 106 of a transmission 108, and at the other end to the input 110 of a differential 112. The differential 112 in turn couples directly to the drive wheels 114 of vehicle 102 by way of axles 116.

Thus, the hydraulic brake 10 may be attached to the frame of a vehicle between the output of the transmission and the input of the differential as a bridge in the drive train of the vehicle. As may be appreciated, the mounting arrangements 22 should be suitably positioned relative to the torque axle 30, and with respect to application on a given vehicle model, to cause the torque axle 30 to align with the normal position for the drive shaft of vehicle 102. In this manner, the brake 10 simply takes movement of the transmission 108 and communicates it directly to the input of the differential 112.

When the vehicle 102 moves, the torque axle 30 of the brake 10 must move. This movement of axle 30 in turn actuates the pump 14. If the lever 70 is in its unobstructing position 70a, the vehicle operates in normal fashion, i.e., it does not experience any braking function as a result of the movement of fluid within hydraulic brake 10. If, however, the exit of fluid from chamber 44 is obstructed by valve 18 by operation of lever 70, then to the extent that such movement is obstructed the movement of vehicle 102 is obstructed. Thus, by resisting rotation of the axle 30, movement of the vehicle 102 is impaired according to a desired braking function. While the brake 10 illustrated herein may not be particularly suited as a primary brake for a vehicle, the brake 10 is well suited as an auxiliary brake to relieve the wear and stress imposed upon a primary brake system, especially for vehicles carrying heavy loads. FIGS. 3 and 4 illustrate a second embodiment of the present invention a brake 200 (FIG. 3) as applied to a trailer 202 (FIG. 4). In FIGS. 3 and 4, the trailer 202 is carried upon a set of ground contacting wheels 204. A first pair of wheels 204 mount upon a first axle 206 of trailer 202 and a second pair of wheels 204 mount upon a second axle 206 of trailer 202. First and second hydraulic brakes 200 each attach to and provide a braking function for each of the corresponding axles 206. Thus, one brake 200 applies a braking force to one pair of wheels 204 and the second brake 200 applies a braking force to the second pair of wheels 204. Each brake 200 includes a control lever 208 for invoking the braking function of the corresponding brake 200. Thus, actuation of levers 208, e.g., as by a mechanical coupling from the trailer to a towing vehicle (not shown in FIG. 4), resists rotation of the axle 206 and thereby impedes the velocity of the trailer 202.

FIG. 3 is a schematic illustration of one of the brakes 200. The brakes 200 take the general form of a vane hydraulic pump. Each brake 200 includes a body 212 defining a generally cylindric chamber 214. The axles 206 rest eccentrically within the chamber 214. The axle 206 further carries a drum 216 which rotates along with the rotation of axle 206. The drum 216 includes radially oriented passageways 217 carrying radially movable pumping wings 218. The pumping wings 218 are biased radially outward and maintain sealing engagement with the inner walls of chamber 214. The outer walls of the drum 216 and inner walls of the chamber 214 define a pumping cavity 220 partitioned by the wings 218. Thus, the pumping wings 218 move through the pumping cavity 220 capturing hydraulic fluid between adjacent ones of the wings 218 and thereby move the hydraulic fluid directly according to movement of the axle

206.

Because of the eccentric mounting of drum 216, the drum 216 approaches very near to a diversion pathway 222 of pump 200. More particularly, body 212 of brake 200 defines a wall portion 224 of chamber 214 which slidingly and sealingly engages the outer surface of drum 216 and wings 218 as wings 218 pass thereby. As a result, hydraulic fluid moving under the influence of wings 218 is diverted from chamber 220 and necessarily moves into and along the pathway 222 and returns to chamber 220 at the opposite end of pathway 222. At the opposite side of brake 200, an opening 226 of chamber 214 exists at a point where drum 216 is most separated from the inner walls of chamber 214. Accordingly, hydraulic fluid existing in the reservoir 228 surrounding brakes 200 circulates into and out of the chambers 214 of brakes 200 by way of openings 226 as the axle 206 rotates.

A lock valve 230 coupled to lever 208 resides along the pathway 222 and may be actuated by movement of lever 208 between the positions indicated at 230a and 230b. In the position 230a, the lock valve 230 allows substantially unencumbered flow of hydraulic fluid along the pathway 222. In the position 230b, however, the lock valve 230 substantially restricts the flow of hydraulic fluid in the pathway 222 and thereby provides a control of velocity over the trajj .xrtue oi iiu tu n-j the flow of hydraulic fluid within brake 200. Intermediate positions of lever 208 oetween the indicated positions 230a and 230b provide intermediate magnitudes of resistance to flow of fluid in the pathway 222.

Thus, by operation of the lever 208, each brake 200 applies a braking force to the wheels 204 of trailer 202. As may be appreciated, by supplying a braking force at the wheels of a trailer 202, the primary braking system of the towing vehicle may apply less braking force and operate in a more efficient and reliable manner.

FIG. 5 illustrates schematically a brake 300 according to the present invention wherein a coupling 302 moves according to movement of a vehicle, i.e., is mechanically coupled to a ground contacting wheel of the vehicle, and a hydraulic pump 304 responds to movement of coupling 302 by forced movement of hydraulic fluid along a pathway 306. A lever 308 operates a lock valve 310 along the pathway 306 in order to controllably restrict movement of fluid along the pathway 306. In the illustration of FIG. 5, the pathway 306 continues through a heat radiating reservoir 312 before returning to the pump 304. The heat radiating reservoir 312 may take a variety of forms to allow use of a volume of hydraulic fluid greater than the capacity of brake 10, and including the use of heat radiating fins or ribs 314 and may be exposed to a flow of air 316 for carrying away heat energy of the hydraulic fluid moving through the braking system of the present invention.

FIG. 6 illustrates use of a second form of cooling mechanism for the hydraulic brake of the present invention as applied to the hydraulic brake 10 of FIGS. 1 and 2, but is applicable to the hydraulic brake 200 of FIGS. 3 and 4. In FIG. 6, the hydraulic brake 10 is shown as previously described including a lever arm 70 for controlling the flow of hydraulic fluid through the passageway 16. The pump 14, as coupled directly to the shaft 30, moves according to movement of the vehicle and restriction of hydraulic fluid in the passageway 16 impedes movement of the vehicle.

The cooling system 400 improves operation of the brake 10 by maintaining an acceptable temperature for hydraulic fluid within brake 10. The cooling system 400 includes a water jacket 402 surrounding the body 12 of brake 10. In this manner, jacket 402 provides a cavity 404 holding a body of fluid, i.e., water, in heat dissipating contact with the body 12 of brake 10. Cavity 404 includes an outlet 406 communicating by way of conduit 408 with a radiator 410 of the vehicle upon which brake 10 is mounted. The outlet 412 of radiator 412 communicates along a conduit 414 to an inlet 416 of cavity 404.

The body of water within cavity 404 circulates through the radiator 410 and thereby dissipates heat energy of the brake 10 by way of the radiator 410. The radiator 410 may be the radiator for the engine of the vehicle and may include a fan 418 as driven by a pulley 420 coupled to the engine (not shown) of the vehicle. The water jacket 402 may be suitably constructed from an aluminum based metal for better dissipating heat while the body 12 of brake 10 may be constructed from a steel based material for better containing the pressures developed within the hydraulic brake 10. By passing the body of water in cavity 404 through the engine radiator, the temperature of hydraulic fluid within brake 20 is maintained substantially consistent, i.e., substantially at the temperature of the water within the radiator system of the vehicle engine.

Thus, an improved brake has been shown and described and may be applied most usefully in the context of heavy duty truck and trailer systems as an auxiliary brake alleviating stress and deterioration of the primary braking system. The brake system of the present invention relies on control over the movement of hydraulic fluid set into motion by virtue of the motion of the vehicle. In this regard, the brake system of the present invention necessarily requires movement of the vehicle in order to apply a braking force. For this reason, the brake system of the present invention finds its greatest utility as an auxiliary brake system, rather than a primary brake system.

It will be appreciated that the present invention is not restricted to the particular embodiment that has been described and illustrated herein, and that variations may be made therein without departing from the scope of the invention as found in the appended claims and equivalents thereof.

Claims

CLAIMS What is Claimed is:

1. A brake system for a vehicle having a ground contacting wheel, the brake system comprising: a mechanical coupling to said wheel whereby said rotational movement of the wheel invokes movement of the coupling and resistive forces applied to the coupling impede such rotation of the wheel; a hydraulic pump responsive to said movement of the coupling by forcibly moving a body of hydraulic fluid along a fluid path; a flow restriction element operative in a first mode of impede flow of fluid along the fluid path and operate in a second mode to allow substantially unencumbered flow of fluid along said path; and a control selectively driving said hydraulic pump between said first and second modes.

2. A brake system according to Claim 1 wherein said fluid path is a fluid circuit whereby said hydraulic pump circulates said fluid around said circuit.

3. A pump according to Claim 2 wherein said hydraulic circuit includes a reservoir in series with said fluid path.

4. A brake according to Claim 2 wherein said brake system further includes a fluid cooling element for taking heat energy away from fluid traveling along said fluid path.

5. A brake system according to Claim 2 wherein said hydraulic circuit includes a heat energy radiating reservoir in series with said fluid path whereby fluid passing through said reservoir loses heat and energy.

6. A brake system according to Claim 1 wherein the vehicle is a motorized vehicle having a drive shaft in a drive train coupling a motor to said wheel and said brake system couples to said drive shaft in such manner to respond to rotation of said drive shaft by said movement of said fluid along said path.

7. A brake system according to Claim 1 wherein said vehicle is a trailer and said brake system couples to an axle of said trailer carrying said wheel in such manner to respond to rotation of said axle by movement of said fluid.

8. A brake system according to Claim 1 wherein said brake further includes a heat dissipating mechanism.

9. A brake according to Claim 8 wherein said heat dissipating mechanism comprises a water jacket surrounding said brake, and means for circulating water through said water jacket and for cooling said water.