Linear-motor-driven Vehicle

Abstract

A number of electric linear-motor driving units are coupled to the bodies of cars in a train in a manner to undergo displacement relative to the bodies when the cars are traveling along a curve and are operating cooperatively with and guided by a reaction rail along a roadway, and this displacement is transmitted by a linkage to steer wheel and suspension systems on which the cars are rolling so as afford bogie action whereby the wheels can follow the roadway with minimum friction, undue stress, and power.

Description

BACKGROUND OF THE INVENTION

The invention relates to an improved electric railway car driving system driven by linear motors.

In general, railway vehicles are so constructed that both wheels in the left and right sides are respectively fixed on one shaft; and, by imparting the rotating power from the prime mover adhesion drive is carried out. In view of this, when the railway vehicles pass through a curved roadway, a so-called "creaking" is caused because the difference of the running distance between the inner rail and the outer rail does not coincide with the difference in the cone of the tread surface, and because of an increased frictional force between the flanges of the outer wheels and the outer rail.

In general, it is a common practice in railways to support and guide railway vehicles by means of flanged wheels or to mount railway vehicles on bogies (known also as bogie trucks and swivel trucks) having support wheels and guide wheels and to drive these vehicles by imparting motive power to the support wheels. Such mechanical arrangements have been adopted as an inevitable result of the use of adhesion drive or friction drive. Such conventional mechanisms are subject to certain limitations, particularly in their application to high-speed transportation means.

Linear motors, on the other hand, effect nonadhesion drive and afford many interesting possibilities. In a linear motor driving system, it is desirable that the gap between the magnetic field of the motor and the reaction rail be maintained at a minimum and, moreover, a constant value in order to obtain high electrical efficiency. It is difficult to attain this desirable feature in practice with bogies of conventional construction when an I-beam (or I-bar) is used as the reaction rail since the center of gravity of the vehicle would then become disadvantageously high. Consequently, there is a need for a vehicular wheel and suspension system (running gear) which, while being of an independent left-and-right, two-axle organization, operates effectively in the same manner as a bogie suspension system when the vehicle is running along a curved path.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide vehicles in which the advantageous features of linear motors and railways are fully utilized.

More specifically, an object of the invention is to provide linear-motor-driven vehicles which can be easily manufactured, operated, and maintained.

Another object of the invention is to provide linear-motor-driven vehicles which are of low empty weight whereby high rates of acceleration and deceleration can be attained and, therefore, are highly economical.

Still another object of the invention is to provide linear-motor-driven vehicles designed to satisfy the above stated need for an independent left-and-right, two-axle suspension system which operates effectively in the same manner as a bogie suspension system in running along a curved path.

The objects of the invention have been achieved by the combination of a wheel and suspension organization in which each vehicle car body is supported on four independent tired wheels similarly as in a conventional motor-vehicle trailer and driven by railway means, that is, linear-motor driving bogies having the multiple functions of driving and guiding each vehicle car and of coupling adjacent vehicles in one embodiment of the invention.

According to the present invention, briefly summarized, there is provided a transportation system having a roadway and a reaction rail therealong, characterized by the combination therewith of a vehicle composed of one or more cars each comprising a car body, at least one linear-motor driving device operating cooperatively with and under guidance by the reaction rail and coupled to the car body in a manner to undergo displacement relative thereto when the car travels along a curve in the roadway, a wheel and suspension system of two-axle, independent-wheel-type supporting the car body in a manner to undergo steering movement relative thereto, and means to interlink the driving device and the wheel and suspension system thereby to cause this system to undergo appropriate steering movement in accordance with the displacement of the driving device.

The nature, principles, details, and utility of the invention will be more clearly apparent from the following detailed description with respect to preferred embodiments of the invention when read in conjunction with the accompanying drawings, in which like parts are designated by like reference numerals and characters.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a diagrammatic side elevation showing an example of vehicle train of an articulated coupler-bogie organization constituting an embodiment of the invention;

FIG. 2 is a diagrammatic, fragmentary plan view indicating the geometric relationships between train cars and a common driving bogie of the vehicle train shown in FIG. 1 when the cars enter a curved path;

FIG. 3 is a fragmentary plan view showing an example of means for supporting an independent wheel assembly and a driving bogie of linear-motor-type of the train shown in FIG. 1;

FIG. 4a is an elevation of the parts shown in FIG. 3 as viewed in the train longitudinal direction;

FIG. 4b is a plan view of the support means shown in FIG. 4a;

FIG. 5 is a diagrammatic side elevation showing an example of a vehicle train of four-wheel bogie organization constituting another embodiment of the invention;

FIG. 6 is a diagrammatic, fragmentary plan view showing the geometric relationships between a car and a driving bogie of the train shown in FIG. 5 when the car enters a curved path;

FIG. 7 is a partial plan view of support means for supporting an independent wheel assembly and a driving bogie of a car in the train illustrated in FIG. 5; and

FIG. 8 is an elevational of the parts shown in FIG. 7 as viewed in the train longitudinal direction.

DETAILED DESCRIPTION

Referring first to FIGS. 1, 2, 3, and 4, the cars (or carriages) of the train illustrated therein have car bodies 5 each mounted on four support wheels 3 which can roll along a roadway 1 provided with a centrally disposed reaction rail 2. A driving device 4 of linear-motor-type straddling the reaction rail 2 is disposed between each pair of adjacent car ends in the train and functions as a coupler therebetween in addition to its functions as a driving and guiding means. Although this driving device is not, strictly speaking, a bogie since it does not have wheels, it is hereinafter referred to as a "driving bogie" because of its swiveled coupling to the car body or bodies and its operation to determine the steering of the car wheels. The extreme ends of the train are provided with detachable driver's cabs 6.

Each car body 5, near each end thereof and near each of the left and right sides thereof, is supported, principally in the vertical direction, on coil springs 13 mounted on an axle block 12, which holds the axle (not shown) of a wheel 3 (comprising two tired wheels in the example shown in FIGS. 3 and 4). Each car body 5, at a point on its longitudinal center near each end thereof, is pin-connected by a vertical coupling pin 20 to one end of a driving bogie 4.

The wheels 3 at one end of one car, the wheels 3 of the near end of another adjacent car, and the driving bogie 4 coupling the adjacent ends of the two cars are interlinked and guided in interrelated movements in the horizontal plane by a linkage described more fully hereinafter and comprising, with respect to each wheel 3, an axle block shaft 11 rotatably supported in horizontal fore-and-aft position by an axle block 12, a link 10 disposed horizontally and pin connected at one end thereof to one end of the shaft 11, a body shaft 9 pin connected at one end thereof to the other end of the shaft 11 and rotatably supported by a bearing member 8 fixed to a longitudinal channel beam 7 constituting a rigid frame member of the car body 5, a normally horizontal link 10a connected at its one end to the other end of the body shaft 9 and at the other end of the shaft 11, an interconnecting link 14 pin connected at its one end to the pin connection between the link 10a and the shaft 11 and at its other end to one end of a link 19 fixed rigidly to one lateral side of the driving bogie 4.

Thus, each car body 5 is supported fore and aft by a so-called two-axle suspension system, in which each of the front and rear axles is cut at its central part to form two independent wheel suspension devices. Accordingly, while this suspension system resembles that of an articulated bogie system, each car body 5, at each end thereof, is supported independently on independent wheel mechanisms having two support wheels 3 as the car runs along the roadway 1.

Thus, the links 10 and 10a, the body shaft 9, and the rotatable shaft 11 of the suspension mechanism of each wheel constitute a four-bar linkage lying substantially in a horizontal plane. The bar formed by shaft 9 is fixed to the car body with respect to movements in this plane but is rotatable within the bearing member 8, whereby the links 10 and 10a and the wheel assembly connected thereto can rotate about the axis of the shaft 9. Furthermore, the axle block 12, axle, and wheel 3 are free to rotate about the axis of the shaft 11.

If, of the plurality of car bodies 5 in one train each supported in the above described manner, the foremost and rearmost car bodies are constructed as bodies with built-in driver's cabs, the train will be the same, in this sense, to a train of general type. In the instant example illustrated, the end car bodies and the intermediate car bodies are all made identical for the purpose of facilitating quantity (mass) production, and the driver's cabs are detachably secured to the extreme outer ends of the end car bodies. This feature, however, is mere incidental and is not an essential part of the present invention.

Each linear-motor driving bogie 4 for driving the vehicles supported in the above described manner straddles the reaction rail 2 vertically installed along the centerline of the roadway 1 and is provided with a linear motor 18 disposed on opposite flank sides of the web of the reaction rail 2 in close proximity thereto. The linear motor 18 is supported by and within a linear-motor frame 15 constituting the main body structure of the driving bogie 4 and provided near each of its front and rear ends with four guide wheels 17 rotatably supported with vertical axes, two wheels thereof being on each side of the reaction rail 2 to clamp and roll along the web thereof, and with a wheel 16 with a horizontal axis supporting the driving bogie and rolling on the upper flange of the reaction rail 2.

The guide wheels 17 and support wheels 16 thus guide the driving bogie 4 and, at the same time, function to maintain the gaps between the linear motor 18 and the reaction rail 2 at optimum values. As mentioned briefly hereinbefore, the two ends of each driving bogie 4, that is, the linear-motor frame 15, are connected by vertical coupling pins 20 to the ends of the adjacent coupled car bodies 5. Thus, the driving bogie 4 and coupling pins 20 function also in the manner of couplers of a railway train, whereby a train composed of any required number of cars can be successively coupled and assembled.

A third rail 21 parallel to reaction rail 2 is provided for contact with the driving bogie 4 for driving and braking each car. Driving and braking can be accomplished by changing over taps and switching phases of a three-phase alternating current fed from the third rail 21 or by feeding a single-phase alternating current or a direct current and carrying out phase control or frequency control by means of an inverter.

While driving and guiding of the vehicle cars and supporting of the car bodies can be accomplished by means of the above described vehicle and railway constructions, it is further necessary to satisfy further one more requirement, which is that of operating a train safely and efficiently along curves in the roadway 1.

When a train of cars as described above enters a curve in the roadway 1, very large side forces would be imparted since each driving bogie 4 and corresponding coupled car bodies 5 are connected by coupling pins 20 if the cars were not provided with means for relieving such forces. Accordingly, it is necessary to determine the displacements of the driving bogie 4 and car bodies 5 and to accomplish steering of the support wheels 3 of each car body 5. This problem of running along a curved path will now be considered in specific terms with reference to FIG. 2.

In FIG. 2, line GHIY represents the path of a curved roadway; line XY is a tangent to this curved path at the fore-and-aft middle point Y of one car body 5a; and line IMN (dot-and-dash line) is the longitudinal centerline of the car body 5a and is displaced parallelly from tangent line XY of the curved path. Line JK is the longitudinal centerline of the leading car body 5b; points A and D designate support points on both sides of linear-motor frame 15; and points B, C, E, and F are pin joints of interconnecting links 14 and links 19.

Points P.sub.1, Q.sub.1, P.sub.2, and Q.sub.2 and points P.sub.3, Q.sub.3, P.sub.4, and Q.sub.4 are pivot points of the right and left links 10 and 10a of the trailing car and leading car, respectively, and points R.sub.1, S.sub.1, R.sub.2, and S.sub.2 and points R.sub.3, S.sub.3, R.sub.4, and S.sub.4 are pin joints between right and left links 10 and 10a and corresponding axle block shafts 11 of the trailing and leading cars, respectively.

Points T.sub.1, U.sub.1, T.sub.2, and U.sub.2 designate the positions prior to movement respectively of pin joints R.sub.1, S.sub.1, R.sub.2, and S.sub.2. Points V.sub.1, V.sub.2, V.sub.3, and V.sub.4 designate the centers of axle blocks 12 of the right and left wheels of the trailing and leading cars, respectively; and reference characters W.sub.1, W.sub.2, W.sub.3, and W.sub.4 designate positions at which support wheels 3 are respectively mounted on axles held by the axle blocks 12.

Pin joints C, F, B and E, which connect interconnecting links 14 and links 19 are spaced apart from support points A and D on opposite lateral sides of the linear-motor frame 15 at distances necessary for reasons of construction such as that of the third rail 21. Pin joints B and E are connected by respective interconnecting links 14 to pin joints S.sub.3 and S.sub.4 on the right and left sides of the leading car, while pin joints C and F are connected by respective interconnecting links 14 to pin joints R.sub.1 and R.sub.2 on the right and left sides of the trailing car.

Furthermore, the support wheels 3 are mounted with distances W.sub.1 V.sub.1, W.sub.2 V.sub.2, W.sub.3 V.sub.3, and W.sub.4 V.sub.4 from the centers V.sub.1, V.sub.2, V.sub.3, and V.sub.4 of their respective axle blocks 12, which are rotatable about their shafts 11, these distances being necessary for the installation of coil springs 13 and other parts.

When a car combination of the above described construction enters a curve in the roadway 1, the driving bogie 4 is guided along curve JHIY by guide wheels 17 provided near the front and rear ends of its linear-motor frame 15, whereby links 10 and 10a of the trailing car are caused by interconnecting links 14 to undergo angular displacement about pin joints P.sub.1, Q.sub.1, P.sub.2, and Q.sub.2 on the side of the car and the pin joints at the free or distal ends of the links 10a and 10 move from their original positions T.sub.1, U.sub.1, T.sub.2, and U.sub.2 to points R.sub.1, S.sub.1, R.sub.2, and S.sub.2, for example.

When the cars are traveling along a straightline roadway, the centerlines of the driving bogie 4 and of the car bodies 5a and 5b coincide, and the pin joints C and F of links 19 and 14 are positioned symmetrically with respect to the centerline. Accordingly, the pin joints R.sub.1, S.sub.1, R.sub.2, and S.sub.2 of the right and left links 10a and 10, the positions of which pin joints are determined by the interconnecting links 14, are respectively at positions T.sub.1, U.sub.1, T.sub.2 and U.sub.2, and the right and left support wheels 3 are directionally parallel to the centerline of the car.

When the cars enter a curve in the roadway, and driving bogie 4 undergoes a displacement, pin joints R.sub.1, S.sub.1, R.sub.2, and S.sub.2 also undergo displacements from points T.sub.1, U.sub.1, T.sub.2, and U.sub.2 in accordance with the displacement of driving bogie 4, and the directions of the support wheels 3 are changed to directions parallel to a tangent to the curved path along which the cars are to travel.

Therefore, by appropriately selecting the respective positions of a pivotal points P.sub.1, Q.sub.1, P.sub.2, and Q.sub.2 on the car body side of links 10a and 10 and the lengths of the body shafts 9, links 10 and 10a, and shafts 11, it is possible to satisfy the above described condition within a specified range of curvatures of curves through which the cars are to travel.

The example described above is that of a vehicle having a suspension system with independent wheel organization and propelled by linear-motor driving bogies. In another embodiment of the invention as illustrated in FIGS. 5, 6, 7, and 8, it is also possible to utilize practically a linear-motor drive system by a similar method for a four-wheel arrangement of conventional type.

The vehicle of this example runs along a roadway 31 provided with a central reaction rail 32 and a third rail 51. The essential parts of each car, most of which are similar to those of the aforedescribed example, are support wheels 33, linear-motor driving bogies 34, a car body 35, longitudinal beams 37 fixed to the car body, fixed links 38, rotatable shafts 39, links 40 and 40a, shafts 41, axle blocks 42, coil springs 43, and interconnecting links 44 interconnecting the wheel and suspension assemblies to the driving bogie 34.

The driving bogie 34 comprises, essentially, a linear-motor frame 45 centrally pivoted by a center pin 50, wheels 46 for supporting the driving bogie, guide wheels 47, a linear motor 48 supported by the linear-motor frame, and a bracket 49 fixed to the linear-motor frame.

Each car body 35 is supported fore and aft by a so-called two-axle suspension system, in which of the front and rear axles is cut at its central part to form independent wheel suspension devices. Referring to FIGS. 7 and 8, a longitudinal beam 37 is fixed to the bottom of the car body 35 on each of the left and right sides thereof and supports fixed links 38 fixed thereto. The links 38 are coupled by way of rotatable shaft 39, links 40 and 40a, and shaft 41 to axle block 42, on which are mounted two coil springs 43 supporting the car body 35. The axle block 42 supports an axle (not shown) on which two support wheels 33 with tires are mounted.

The independent wheel suspension mechanism of the above described organization is interlinked through link 44 to the linear-motor type driving bogie 34, link 44 being pin connected at one end thereof to one end of shaft 41 and at the other end thereof to bracket 49. Accordingly, the car body 35 in the instant example travels along roadway 31 as it is supported by independent wheel and suspension devices each having two support wheels 33.

Each of the linear-motor driving bogies 34 for driving this car has a linear-motor frame 45 supporting therewithin the linear motor 48 in a position such that the motor is disposed to confront the opposite flanks of the web of the reaction rail 32 installed upright along the center of the roadway 31. The four guide wheels 47 provided near the front and rear of each linear-motor frame 45 and the bogie supporting wheels 46 function to guide the bogie and, at the same time, to maintain the optimum gaps between the linear motor 48 and the reaction rail 32. The pivot pin 50 connecting the center of the linear-motor frame 45 to the car body 35 has the same construction and operation as a bogie of a conventional railway car.

The driving and braking of the car is accomplished by changing over taps and switching phases of three-phase AC power supplied from the third rail 51, or, alternatively, by supplying single-phase AC power or DC power and controlling phase or frequency by means of an inverter.

When a train of a plurality of these cars enters a curve in the roadway 31, very large side forces would be imparted since each driving bogie 34 and its car body 35 are connected by a pivot pin 50 if means for relieving such forces were not provided. Accordingly, it is necessary to detect the displacements of the driving bogie 34 and the car body 35 and to effect steering of the support wheels 33 of the car body 35 in the manner described below with reference to FIG. 6.

In FIG. 6, line Ga Ma Ya represents a curved path of vehicle travel, and line Xa Ya is a tangent to the curved path at the middle point Ya of the car body 35 in the fore-and-aft direction thereof. Line La Ma Na (intermittent line) is the centerline of the car body 35 and is offset to one side from and parallelly to tangent line Xa Ya by a distance equal to the displacement of pivot pin 50 from the original point.

Points Aa and Ba are support points at the front and rear parts of the linear-motor frame 45, and one end of interconnecting link 44 is pin connected to support point Aa. These pivots shift to positions Ca and Da, for example, when the vehicle enters a curve in the roadway. The corresponding positions after this shift of the support points of the right and left links 40 and 40a are designated by Pa.sub.1, Qa.sub.1, Pa.sub.2, and Qa.sub.2, and the corresponding positions of the support points at the ends of the shafts 41 are designated by Ra.sub.1, Sa.sub.1, Ra.sub.2, and Sa.sub.2.

Points Ea.sub.1, Fa.sub.1, Ea.sub.2, and Fa.sub.2 designate the pivot points of the links 40 and 40a on the car body side prior to the shift, and points Ta.sub.1, Ua.sub.1, Ta.sub.2, and Ua.sub.2 designate the pivot points on the wheel side prior to the shift. Points Va.sub.1 designate the centers of the axle blocks 42, and points Wa.sub.1 and Wa.sub.2 indicate the mounting positions of the support wheels 33 with respect to the centers of the axle blocks 42, the support wheels 33 being thus mounted with distances Wa.sub.1 Va.sub.1 and Wa.sub.2 Va.sub.2 necessary for installing parts such as the coil springs 43 on the axle blocks 42 which are rotatable about the shafts 41.

When a train of cars each of the above described organization enters a curve, driving bogie 34 is guided along path GaCaDaYa at points Ca and Da by guide wheels 47 provided at the front and rear of linear-motor frame 45 of the driving bogie, and pivot pin 50 shifts to point Ma. Accordingly, pivot points Pa.sub.1, Qa.sub.1, Pa.sub.2, and Qa.sub.2 on the car body side respectively shift from their former positions Ea.sub.1, Fa.sub.1, Ea.sub.2, and Fa.sub.2, while pivot points Ra.sub.1, Sa.sub.1, Ra.sub.2, and Sa.sub.2 respectively shift from their former positions Ta.sub.1, Ua.sub.1, Ta.sub.2, and Ua.sub.2. Thus, positioning (steering) of the wheel and suspension system is accomplished automatically and in an appropriate manner from front support pivot point Ca of linear-motor frame 45 through link 44.

When the vehicle is running along a straightline path, pivot points Aa and Ba of driving bogie 34 are on the car body centerline. Consequently, pivot points Ra.sub.1, Sa.sub.1, Ra.sub.2, and Sa.sub.2 of links 40 and 40 a, the positions of which are determined by links 44, are respectively at positions Ta.sub.1, Ua.sub.1, Ta.sub.2, and Ua.sub.2, and the right and left support wheels 33 are aligned parallelly to the car body centerline.

When the vehicle enters a curve, a driving bogie 34 undergoes a displacement, whereby pivot points Ra.sub.1, Sa.sub.1, Ra.sub.2, and Sa.sub.2 are caused to shift from positions Ta.sub.1, Ua.sub.1, Ta.sub.2, and Ua.sub.2 in accordance with this displacement, and the directions of support wheels 33 are changed to align with the tangent direction of the curve along which vehicle is to travel. Therefore, by appropriately selecting the positions of the pivot points Ea.sub.1, Fa.sub.1, Ea.sub.2, and Fa.sub.2 on the car body side of the links 40 and 40a and the lengths of the links 40 and 40a and rotatable shafts 41, the above stated conditions can be satisfied within a specified curvature of the curve through which the vehicle is to pass.

Claims

I claim:

1. In an electric linear-motor transportation system having a roadway and a reaction rail installed along said roadway, the combination with said reaction rail and roadway of a vehicle including a car body having a longitudinal axis, and a driving and supporting combination comprising: a first linear-motor driving device operating cooperatively with and under guidance by the reaction rail to drive said vehicle along the roadway, first coupling means connecting said driving device to said car body to cause said driving device to undergo displacement relative to said car body axis when the car travels along a curve in a roadway, a pair of support assemblies comprising a wheel and suspension system of two axle, independent-wheel construction, means coupling said car body to said suspension system to permit said independent wheels to undergo steering movement relative to said car body, and link means coupling said driving device to each said wheel and suspension system, said link means comprising a pair of rigid members, said members having inner ends pivotally connected to opposing sides of said driving device and having outer ends pivotally coupled to said respective support assemblies to cause said system to undergo appropriate steering movement in accordance with said displacement of said driving device.

2. The invention as claimed in claim 1, further comprising another said vehicle and second coupling means for connecting said other vehicle to said first driving device, wherein said first and second coupling means comprise respective pivotal means connected to adjacent ends of said respective vehicles, and wherein said first driving device comprises the driving device for said other vehicle.

3. The invention as claimed in claim 1, in which said vehicle has a pair of said driving and supporting combinations, one of said combinations disposed at one end of said car body, and the other of said combinations disposed at the other end of said car body.

4. The invention as claimed in claim 2 including a train comprising a plurality of said vehicles coupled end-to-end in a line.

5. The invention as claimed in claim 1 in which said wheel and suspension system of each vehicle comprises front left and right wheel assemblies and rear left and right wheel assemblies, and spring means connecting said wheel assemblies to said car body, and in which each wheel assembly comprises at least one wheel, and axle on which said wheel is mounted, and a four-bar linkage in a horizontal plane, a first bar of each of said 4-bar linkage is one of said rigid members, a second bar of said 4-bar linkage comprises a bar disposed perpendicularly to said axle and pivotally connected at one end to said rigid member, and third and fourth bars of said 4-bar linkage have ends pivotally coupled to said car body for pivotal movement in said horizontal plane, and have opposing ends pivotally coupled respectively to the opposing ends of said second bar.