CN103883195B - Rail vehicle switching mechanism for front cover and method for designing - Google Patents

Abstract

The present invention relates to a kind of rail vehicle switching mechanism for front cover and method for designing, comprise symmetrically arranged left front cover and right front cover, drive the actuating unit of left front cover and right front cover opening and closing, actuating unit comprises mount pad, opening and closing cylinder, left quadric chain and right quadric chain, opening and closing cylinder is fixed on mount pad, mount pad is fixed on underframe, left quadric chain and right connecting rod mechanism are made up of continuous print four connecting rods respectively, the leading section of left linkages mechanism is fixedly connected with right front cover with left front cover respectively, the starting point of two first connecting rods in left and right is hinged on fixed axis jointly, fixed axis is fixed on described mount pad, the tie point mutual cross-articulation of two, left and right between second connecting rod and third connecting rod.The present invention achieves left and right front shroud by simple quadric chain and opens by special exercise track, and to get around other obstruction, a step action completes, and effectively reduces the complexity of opening and closing device, reduces the cost of device, accomplishes that structure is simple, practical function.<!--1-->

Description

Rail vehicle switching mechanism for front cover and method for designing

Technical field

The present invention relates to a kind of front shroud of rail vehicle head, particularly a kind of rail vehicle switching mechanism for front cover and method for designing, belong to rail vehicle manufacturing technology field.

Background technology

Rail vehicle is when hanging together or rescue, need the connection carrying out hitch, in order to meet the demand that vehicle hangs together, the leading section of current track vehicle headstock all adopts the front cover structure of split type automatic shutter, front shroud is driven by switching mechanism, when vehicle normally runs, front shroud closes, when needed, open about front shroud, reserve necessary space for hitch hangs together, hitch carries out automatically unlocking and extends and be connected, with the heavily connection realized between train or rescue fault train.

Cover opening/closing device many employings slideway, gathering sill mechanism before the existing EMUs of order, or direct Unscrew, movement locus is simple, and front shroud is built in vehicle body after opening.Along with making constant progress of rail vehicle, drivers' cab profile is maked rapid progress and inner space is nervous, front shroud to open sports envelope space more and more less, open track more and more harsher, front shroud needs multistep action or special track just can open, because existing switching mechanism running orbit is simple, be difficult to reach opening and closing requirement.

Summary of the invention

Main purpose of the present invention is to solve the problem and deficiency, a kind of rail vehicle switching mechanism for front cover and method for designing are provided, the front shroud opening and closing problem that solution must not be opened by simple rotation or rectilinear motion, makes front shroud can open according to particular track, and can avoid interfering with other component.

For achieving the above object, technical scheme of the present invention is:

A kind of rail vehicle switching mechanism for front cover, comprise symmetrically arranged left front cover and right front cover, drive the actuating unit of described left front cover and right front cover opening and closing, described actuating unit is fixed on floor underframe for vehicle, described actuating unit comprises mount pad, opening and closing cylinder, left quadric chain and right quadric chain, described opening and closing cylinder is fixed on described mount pad, described mount pad is fixed on described underframe, described left quadric chain and right quadric chain are respectively by continuous print first connecting rod, second connecting rod, third connecting rod, double leval jib forms, hinged between described first connecting rod and second connecting rod, described second connecting rod and third connecting rod form an elongated straight-bar, described third connecting rod is connected with fixed angle between double leval jib, the leading section of two described double leval jib is fixedly connected with right front cover with described left front cover respectively, the starting point of two the described first connecting rods in left and right is hinged on fixed axis jointly, described fixed axis is fixed on described mount pad, mutual cross-articulation between the tie point of left second connecting rod and left third connecting rod and the tie point of right second connecting rod and right third connecting rod, the expansion link of described opening and closing cylinder is connected with described left quadric chain and right quadric chain.

Further, described left quadric chain and the second connecting rod in right quadric chain, third connecting rod and double leval jib are set to parallel upper and lower two respectively, connected by connecting rod between upper and lower two described double leval jib, the initiating terminal of upper and lower two described second connecting rods is hinged by hinge.

Further, the telescopic end of described opening and closing cylinder is connected by two the described first connecting rods in push rod and left and right, or the telescopic end of described opening and closing cylinder is connected to the crosspoint place between described second connecting rod and third connecting rod.

Further, the crosspoint place between the described second connecting rod in two, left and right and third connecting rod arranges an intermediate pin, and described mount pad is provided with a middle chute along car body longitudinal centre line, and described intermediate pin slides in described middle chute.

Further, in left and right, the bottom at the tie point place of described third connecting rod and double leval jib is respectively provided with roller or slide block, and described roller or slide block move in the plane of described mount pad.

Further, described mount pad is provided with the slideway that the movement locus along described roller or slide block is arranged, and described roller or slide block move in described slideway.

Further, leading section movement locus point E (x, the y) coordinate of described double leval jib meets following equation,

$\left\{\begin{array}{c}x=\frac{L_1\&CenterDot;L_3}{L_2}\&CenterDot;\sin \mathrm{\&alpha;}+\cos \&lsqb;\frac{3\mathrm{\&pi;}}{2}-\mathrm{\&beta;}-\arcsin \left(\frac{L_1\sin \mathrm{\&alpha;}}{L_2}\right)\&rsqb;\&CenterDot;L_4\\ y=\cos \mathrm{\&alpha;}\&CenterDot;L_1+\cos \left(\arcsin \frac{\sin \mathrm{\&alpha;}\&CenterDot;L_1}{L_2}\right)\&CenterDot;(L_2+L_3)+\sin \&lsqb;\frac{3\mathrm{\&pi;}}{2}-\mathrm{\&beta;}-\arcsin \left(\frac{L_1\sin \mathrm{\&alpha;}}{L_2}\right)\&rsqb;\&CenterDot;L_4\end{array}\right.$

Wherein, angle when angle [alpha] is described first connecting rod original state and between car body longitudinal centre line, span is

L ₁, L ₂, L ₃, L ₄be respectively the length value of first connecting rod, second connecting rod, third connecting rod and double leval jib;

Angle beta is the angle between described third connecting rod and described double leval jib, and angle beta is constant.

Further, the movement locus coordinate of the tie point D (x, y) of described third connecting rod and double leval jib meets following equation,

$y=cos\&lsqb;\arcsin (\frac{L_2}{L_1\&CenterDot;L_3}\&CenterDot;x)\&rsqb;\&CenterDot;L_1+cos\&lsqb;\arcsin \left(\frac{x}{L_3}\right)\&rsqb;\&CenterDot;(L_2+L_3)$

Wherein, x span is:

L ₁, L ₂, L ₃, L ₄be respectively the length value of first connecting rod, second connecting rod, third connecting rod and double leval jib.

Another technical scheme of the present invention is:

A method for designing for above-mentioned rail vehicle switching mechanism for front cover, specifically comprises the steps:

A, first suppose the length value L of first connecting rod, second connecting rod, third connecting rod and double leval jib ₁, L ₂, L ₃, L ₄and angle beta is a numerical value, substitute in following formula, determine the movement locus that leading section E (x, y) of left and right double leval jib is put,

$\left\{\begin{array}{c}x=\frac{L_1\&CenterDot;L_3}{L_2}\&CenterDot;\sin \mathrm{\&alpha;}+\cos \&lsqb;\frac{3\mathrm{\&pi;}}{2}-\mathrm{\&beta;}-\arcsin \left(\frac{L_1\sin \mathrm{\&alpha;}}{L_2}\right)\&rsqb;\&CenterDot;L_4\\ y=\cos \mathrm{\&alpha;}\&CenterDot;L_1+\cos \left(\arcsin \frac{\sin \mathrm{\&alpha;}\&CenterDot;L_1}{L_2}\right)\&CenterDot;(L_2+L_3)+\sin \&lsqb;\frac{3\mathrm{\&pi;}}{2}-\mathrm{\&beta;}-\arcsin \left(\frac{L_1\sin \mathrm{\&alpha;}}{L_2}\right)\&rsqb;\&CenterDot;L_4\end{array}\right.$

Wherein, angle when angle [alpha] is described first connecting rod original state and between car body longitudinal centre line, span is

Angle beta is the angle between described third connecting rod and described double leval jib, and angle beta is constant;

B, constantly adjust length value L ₁, L ₂, L ₃, L ₄and angle β value, make the movement locus of leading section each point get around obstruction;

C, when the movement locus of double leval jib leading section, left and right each point can get around obstruction, length value L now ₁, L ₂, L ₃, L ₄and angle β value is end value;

D, by length value L ₁, L ₂, L ₃end value substitute into following formula, calculate the movement locus of the tie point D (x, y) of described third connecting rod and double leval jib,

$y=cos\&lsqb;\arcsin (\frac{L_2}{L_1\&CenterDot;L_3}\&CenterDot;x)\&rsqb;\&CenterDot;L_1+cos\&lsqb;\arcsin \left(\frac{x}{L_3}\right)\&rsqb;\&CenterDot;(L_2+L_3)$

Wherein, x span is:

E, flat shape by the movement locus determination mount pad of D point.

Further, in left and right, the bottom at the tie point D point place of described third connecting rod and double leval jib is respectively provided with roller or slide block, and described roller or slide block roll in the plane of described mount pad.

To sum up content, a kind of rail vehicle switching mechanism for front cover of the present invention and method for designing, solve the front shroud opening and closing problem do not opened by simple rotation or rectilinear motion, achieve left and right front shroud by simple quadric chain to open by special exercise track, to get around other obstruction, avoid interfering with other component, also the action making some need multistep to open is combined into a step action and has come, effectively reduce the complexity of opening and closing device, reduce the cost of device, accomplish that structure is simple, practical function, be suitable for the front shroud of most of rail vehicle.

Accompanying drawing explanation

Fig. 1 is front cover structure schematic diagram of the present invention;

Fig. 2 is the structural representation of switching mechanism for front cover of the present invention;

Fig. 3 is four-bar linkage structure trajectory calculation schematic diagram of the present invention.

As shown in figures 1 and 3, left front cover 1, right front cover 2, actuating unit 3, mount pad 4, opening and closing cylinder 5, left quadric chain 6, right quadric chain 7, left first connecting rod 8, right first connecting rod 9, left second connecting rod 10, right second connecting rod 11, left third connecting rod 12, right third connecting rod 13, left double leval jib 14, right double leval jib 15, left first pin joint 16, right first pin joint 17, crosspoint 18, fixed axis 19, left connecting rod 20, right connecting rod 21, left hinge 22, right hinge 23, middle chute 24.

Detailed description of the invention

Below in conjunction with accompanying drawing and detailed description of the invention, the present invention is described in further detail:

Embodiment one:

As shown in Figure 1, left front cover 1 and right front cover 2 is symmetrically set with along car body longitudinal centre line at the head of railway vehicle cab, left front cover 1 and right front cover 2 curved, consistent with the streamline profile of car body head during closedown, running resistance is not increased when ensureing vehicle operating, left front cover 1 is connected with actuating unit 3 with right front cover 2, left front cover 1 and right front cover 2 open or close to both sides under the driving of actuating unit 3, in opening procedure, left front cover 1 and right front cover 2 will to avoid in car other component, and actuating unit 3 is fixed in the upper plane of floor underframe for vehicle.Left front cover 1 and right front cover 2 all adopt glass fiber reinforced plastic manufacture, not only can ensure its strength and stiffness, can also reduce weight, meet the light-weighted requirement of vehicle, also improve the overall appearance effect of headstock simultaneously.

As shown in Figures 2 and 3, for driving the actuating unit 3 of left front cover 1 and right front cover 2 opening and closing to comprise mount pad 4, opening and closing cylinder 5, left quadric chain 6 and right quadric chain 7.Wherein, mount pad 4 is horizontal frame structures, be fixed on floor underframe for vehicle, opening and closing cylinder 5 is fixedly mounted on mount pad 4, the expansion link end of opening and closing cylinder 5 is connected with left quadric chain 6 and right quadric chain 7, drive left quadric chain 6 and right quadric chain 7 to move, and then drive left front cover 1 and right front cover 2 opening and closing.

Left quadric chain 6 is made up of the left first connecting rod of continuous print 8, left second connecting rod 10, left third connecting rod 12, left double leval jib 14.Right quadric chain 7 is made up of the right first connecting rod of continuous print 9, right second connecting rod 11, right third connecting rod 13, right double leval jib 15.

The starting point (A point) of left first connecting rod 8 and right first connecting rod 9 is hinged on fixed axis 19 jointly, and fixed axis 19 is fixed on mount pad 4.The leading section of left double leval jib 14 is fixedly connected with left front cover 1 (E point), and the leading section of right double leval jib 15 is fixedly connected with right front cover 2 (E point).

Hinged at left first pin joint 16 (B point) place between left first connecting rod 8 and left second connecting rod 10, hinged at right first pin joint 17 (B point) place between right first connecting rod 9 and right second connecting rod 11, left second connecting rod 10 and left third connecting rod 12 form an elongated straight-bar, right second connecting rod 11 is same with right third connecting rod 13 forms an elongated straight-bar, left and right two parts are at left second connecting rod 10 and left third connecting rod 12, right second connecting rod 11 intersects mutually with the tie point place of right third connecting rod 13, in crosspoint 18 (C point) mutual left and right, place, two parts are hinged.Left third connecting rod 12 and (D point) between left double leval jib 14 and between right third connecting rod 13 with right double leval jib 15 (D point) be all connected with fixed angle β.

Left second connecting rod 10, left third connecting rod 12, left double leval jib 14, right second connecting rod 11, right third connecting rod 13 and right double leval jib 15 are set to parallel upper and lower two respectively, be fixedly connected with by left connecting rod 20 between upper and lower two left side double leval jib 14, connected by right connecting rod 21 between upper and lower two right side double leval jib 15, the initiating terminal of upper and lower two left second connecting rods 10 is articulated and connected by left hinge 22, and the initiating terminal of upper and lower two right second connecting rods 11 is articulated and connected by right hinge 23.The leading section of upper and lower two left side double leval jib 14 is fixedly connected on left front cover 1, and the leading section of upper and lower two right side double leval jib 15 is fixedly connected on right front cover 2, makes left front cover 1 and right front cover 2 motion process more steady, and can improve its bulk strength and rigidity.

The telescopic end of opening and closing cylinder 5 is connected to crosspoint 18 place, when the expansion link of opening and closing cylinder 5 stretches out forward, promote crosspoint 18 to move forward, left first connecting rod 8 and right first connecting rod 9 mutually close up under thrust, quadric chain extend, left double leval jib 14 and right double leval jib 15 mutually close up drive left front cover 1 and right front cover 2-in-1 hold together close.On the contrary, when the expansion link of opening and closing cylinder 5 is retracted backward, promote crosspoint 18 and move backward, drive left front cover 1 and right front cover 2 to open to both sides.

The movement locus in crosspoint 18 is on the direction of car body longitudinal centre line all the time, in order to ensure that parallel motion is steady, in the present embodiment, at crosspoint 18 place, one intermediate pin (not shown) is set downwards, mount pad 4 is provided with a middle chute 24 along car body longitudinal centre line, and intermediate pin slides in middle chute 24.

For quadric chain, length and the angle of left quadric chain 6 and right quadric chain 7 are all identical, when length and angle are determined, the movement locus of the tie point (D point) between left third connecting rod 12 and left double leval jib 14 and the tie point (D point) between right third connecting rod 13 and right double leval jib 15 is fixing, in the present embodiment, roller or slide block is respectively provided with in the bottom of left and right tie point (D point), according to the shape of the Its Track Design mount pad 4 of D point, roller or slide block is made to roll in the plane of mount pad 4 or slide, to the motion of quadric chain to support preferably.Mount pad 4 can also arrange corresponding slideway by the movement locus of D point, make roller or slide block roll in slideway or slide.

Namely the movement locus of left double leval jib 14 and right double leval jib 15 leading section each point represents the movement locus of left front cover 1 and right front cover 2, and the movement locus that E (x, y) puts will avoid all obstructions.

The movement locus coordinate that left double leval jib 14 and right double leval jib 15 leading section E (x, y) are put meets following equation:

$\left\{\begin{array}{c}x=\frac{L_1\&CenterDot;L_3}{L_2}\&CenterDot;\sin \mathrm{\&alpha;}+\cos \&lsqb;\frac{3\mathrm{\&pi;}}{2}-\mathrm{\&beta;}-\arcsin \left(\frac{L_1\sin \mathrm{\&alpha;}}{L_2}\right)\&rsqb;\&CenterDot;L_4\\ y=\cos \mathrm{\&alpha;}\&CenterDot;L_1+\cos \left(\arcsin \frac{\sin \mathrm{\&alpha;}\&CenterDot;L_1}{L_2}\right)\&CenterDot;(L_2+L_3)+\sin \&lsqb;\frac{3\mathrm{\&pi;}}{2}-\mathrm{\&beta;}-\arcsin \left(\frac{L_1\sin \mathrm{\&alpha;}}{L_2}\right)\&rsqb;\&CenterDot;L_4\end{array}\right.$

Wherein, angle [alpha] is left first connecting rod 8 and the angle of right first connecting rod 9 when original state and between car body longitudinal centre line, and angle [alpha] span is

L ₁for the length of left first connecting rod 8 and right first connecting rod 9, L ₂for the length of left second connecting rod 10 and right second connecting rod 11, L ₃for length, the L of left third connecting rod 12 and right third connecting rod 13 ₄for the length of left double leval jib 14 and right double leval jib 15.Wherein, L ₁and L ₂numerical value equal.

Angle beta is left third connecting rod 12 and left double leval jib 14 and the angle between right third connecting rod 13 and right double leval jib 15, and angle beta is constant.

The movement locus coordinate of left third connecting rod 12 and left double leval jib 14 and the tie point D (x, y) between right third connecting rod 13 and right double leval jib 15 meets following equation,

$y=cos\&lsqb;\arcsin (\frac{L_2}{L_1\&CenterDot;L_3}\&CenterDot;x)\&rsqb;\&CenterDot;L_1+cos\&lsqb;\arcsin \left(\frac{x}{L_3}\right)\&rsqb;\&CenterDot;(L_2+L_3)$

Wherein, x span is:

Be described below in detail the method for designing of above-mentioned rail vehicle switching mechanism for front cover, specifically comprise the steps:

A, first suppose length value L ₁, L ₂, L ₃, L ₄and angle beta is a numerical value, substitute in following formula, determine the movement locus that left double leval jib 14 and right double leval jib 15 leading section E (x, y) are put,

$\left\{\begin{array}{c}x=\frac{L_1\&CenterDot;L_3}{L_2}\&CenterDot;\sin \mathrm{\&alpha;}+\cos \&lsqb;\frac{3\mathrm{\&pi;}}{2}-\mathrm{\&beta;}-\arcsin \left(\frac{L_1\sin \mathrm{\&alpha;}}{L_2}\right)\&rsqb;\&CenterDot;L_4\\ y=\cos \mathrm{\&alpha;}\&CenterDot;L_1+\cos \left(\arcsin \frac{\sin \mathrm{\&alpha;}\&CenterDot;L_1}{L_2}\right)\&CenterDot;(L_2+L_3)+\sin \&lsqb;\frac{3\mathrm{\&pi;}}{2}-\mathrm{\&beta;}-\arcsin \left(\frac{L_1\sin \mathrm{\&alpha;}}{L_2}\right)\&rsqb;\&CenterDot;L_4\end{array}\right.$

Wherein, angle [alpha] is left first connecting rod 8 and the angle of right first connecting rod 9 when original state and between car body longitudinal centre line, and angle [alpha] span is

E (x, y) point can select several main movement characteristic points of front shroud outline and Internal periphery, as the peak of two end points and centre.

B, constantly adjust length value L ₁, L ₂, L ₃, L ₄and angle β value, and then draw different E (x, y) movement locus put, compare with obstruction coordinate and calculate the length that (inequality calculates) tentatively determines each connecting rod, make leading section E (x, y) movement locus put gets around obstruction, and this step can have been calculated automatically by computer.

C, when the movement locus of left double leval jib 14 and right double leval jib 15 leading section each point can get around obstruction, length value L now ₁, L ₂, L ₃, L ₄and angle β value is end value, in the present embodiment, through calculating accurately, draw L ₁=L ₂=398mm, L ₃=318mm, L ₄=360mm, β=136 degree.

D, by length value L ₁, L ₂, L ₃end value substitute into following formula, calculate the movement locus of tie point D (x, y),

Wherein, x span is:

E, flat shape by the movement locus determination mount pad 4 of D point.

F, be respectively provided with roller or slide block in the bottom of left and right tie point (D point), according to the shape of the Its Track Design mount pad 4 of D point, roller or slide block is made to roll in the plane of mount pad 4 or slide, to the motion of quadric chain to support preferably.Mount pad 4 can also arrange corresponding slideway by the movement locus of D point, make roller or slide block roll in slideway or slide.

By above-mentioned simple calculation procedure and the specific connected mode of quadric chain, namely by controlling the length (L of each connecting rod ₁, L ₂, L ₃, L ₄) and connecting rod initial state angle (α, β), namely various rail vehicle front shroud special exercise track can be realized, avoid interfering with other component, make some need multistep opening action to be combined into a step action to have come, effectively reduce the complexity of device, reduce installation cost, accomplish that structure is simple, practical function, and the front cover opening/closing device being suitable for most of rail vehicle.

Embodiment two:

Be with embodiment one difference, the telescopic end of opening and closing cylinder 5 is connected with left first connecting rod 8 and right first connecting rod 9 by push rod (not shown), push rod divides canned paragraph and rotational segment two sections, the expansion link of opening and closing cylinder 5 is fixedly connected with canned paragraph, rotational segment is two and is connected with left first connecting rod 8 and right first connecting rod 9 respectively, is connected between canned paragraph and rotational segment by axis of rotation.When the expansion link of opening and closing cylinder 5 stretches out forward, the left first connecting rod of push rod driven forward 8 and right first connecting rod 9, left first connecting rod 8 and right first connecting rod 9 mutually close up under thrust, quadric chain extend, left double leval jib 14 and right double leval jib 15 mutually close up drive left front cover 1 and right front cover 2-in-1 hold together close.On the contrary, when the expansion link of opening and closing cylinder 5 is retracted backward, left front cover 1 and right front cover 2 is driven to open to both sides.

As mentioned above, plan content given by reference to the accompanying drawings, can derive similar technical scheme.In every case be the content not departing from technical solution of the present invention, any simple modification done above embodiment according to technical spirit of the present invention, equivalent variations and modification, all still belong in the scope of technical solution of the present invention.

Claims (10)

1. a rail vehicle switching mechanism for front cover, comprise symmetrically arranged left front cover and right front cover, drive the actuating unit of described left front cover and right front cover opening and closing, described actuating unit is fixed on floor underframe for vehicle, it is characterized in that: described actuating unit comprises mount pad, opening and closing cylinder, left quadric chain and right quadric chain, described opening and closing cylinder is fixed on described mount pad, described mount pad is fixed on described underframe, described left quadric chain and right quadric chain are respectively by continuous print first connecting rod, second connecting rod, third connecting rod, double leval jib forms, hinged between described first connecting rod and second connecting rod, described second connecting rod and third connecting rod form an elongated straight-bar, described third connecting rod is connected with fixed angle between double leval jib, the leading section of two described double leval jib is fixedly connected with right front cover with described left front cover respectively, the starting point of two the described first connecting rods in left and right is hinged on fixed axis jointly, described fixed axis is fixed on described mount pad, mutual cross-articulation between the tie point of left second connecting rod and left third connecting rod and the tie point of right second connecting rod and right third connecting rod, the expansion link of described opening and closing cylinder is connected with described left quadric chain and right quadric chain.

2. rail vehicle switching mechanism for front cover according to claim 1, it is characterized in that: described left quadric chain and the second connecting rod in right quadric chain, third connecting rod and double leval jib are set to parallel upper and lower two respectively, connected by connecting rod between upper and lower two described double leval jib, the initiating terminal of upper and lower two described second connecting rods is hinged by hinge.

3. rail vehicle switching mechanism for front cover according to claim 1 and 2, it is characterized in that: the telescopic end of described opening and closing cylinder is connected by two the described first connecting rods in push rod and left and right, or the telescopic end of described opening and closing cylinder is connected to the crosspoint place between described second connecting rod and third connecting rod.

4. rail vehicle switching mechanism for front cover according to claim 1 and 2, it is characterized in that: the crosspoint place between the described second connecting rod in two, left and right and third connecting rod arranges an intermediate pin, described mount pad is provided with a middle chute along car body longitudinal centre line, and described intermediate pin slides in described middle chute.

5. rail vehicle switching mechanism for front cover according to claim 1 and 2, it is characterized in that: in left and right, the bottom at the tie point place of described third connecting rod and double leval jib is respectively provided with roller or slide block, described roller or slide block move in the plane of described mount pad.

6. rail vehicle switching mechanism for front cover according to claim 5, is characterized in that: on described mount pad, be provided with the slideway that the movement locus along described roller or slide block is arranged, described roller or slide block move in described slideway.

7. rail vehicle switching mechanism for front cover according to claim 1 and 2, is characterized in that: leading section movement locus point E (x, the y) coordinate of described double leval jib meets following equation,

$\left\{\begin{array}{c}x=\frac{L_1\&CenterDot;L_3}{L_2}\&CenterDot;\sin \mathrm{\&alpha;}+\cos \&lsqb;\frac{3\mathrm{\&pi;}}{2}-\mathrm{\&beta;}-\arcsin \left(\frac{L_1\sin \mathrm{\&alpha;}}{L_2}\right)\&rsqb;\&CenterDot;L_4\\ y=\cos \mathrm{\&alpha;}\&CenterDot;L_1+\cos \left(\arcsin \frac{\sin \mathrm{\&alpha;}\&CenterDot;L_1}{L_2}\right)\&CenterDot;(L_2+L_3)+\sin \&lsqb;\frac{3\mathrm{\&pi;}}{2}-\mathrm{\&beta;}-\arcsin \left(\frac{L_1\sin \mathrm{\&alpha;}}{L_2}\right)\&rsqb;\&CenterDot;L_4\end{array}\right.$

Wherein, angle when angle [alpha] is described first connecting rod original state and between car body longitudinal centre line, span is

L ₁, L ₂, L ₃, L ₄be respectively the length value of first connecting rod, second connecting rod, third connecting rod and double leval jib;

Angle beta is the angle between described third connecting rod and described double leval jib, and angle beta is constant.

8. rail vehicle switching mechanism for front cover according to claim 1 and 2, is characterized in that: the movement locus coordinate of the tie point D (x, y) of described third connecting rod and double leval jib meets following equation,

$y=cos\&lsqb;\arcsin (\frac{L_2}{L_1\&CenterDot;L_3}\&CenterDot;x)\&rsqb;\&CenterDot;L_1+cos\&lsqb;\arcsin \left(\frac{x}{L_3}\right)\&rsqb;\&CenterDot;(L_2+L_3)$

Wherein, x span is:

L ₁, L ₂, L ₃, L ₄be respectively the length value of first connecting rod, second connecting rod, third connecting rod and double leval jib.

9. a method for designing for the rail vehicle switching mechanism for front cover as described in any one of claim 1-8, is characterized in that, specifically comprise the steps:

A, first suppose the length value L of first connecting rod, second connecting rod, third connecting rod and double leval jib ₁, L ₂, L ₃, L ₄and angle beta is a numerical value, substitute in following formula, determine the movement locus that leading section E (x, y) of left and right double leval jib is put,

$\left\{\begin{array}{c}x=\frac{L_1\&CenterDot;L_3}{L_2}\&CenterDot;\sin \mathrm{\&alpha;}+\cos \&lsqb;\frac{3\mathrm{\&pi;}}{2}-\mathrm{\&beta;}-\arcsin \left(\frac{L_1\sin \mathrm{\&alpha;}}{L_2}\right)\&rsqb;\&CenterDot;L_4\\ y=\cos \mathrm{\&alpha;}\&CenterDot;L_1+\cos \left(\arcsin \frac{\sin \mathrm{\&alpha;}\&CenterDot;L_1}{L_2}\right)\&CenterDot;(L_2+L_3)+\sin \&lsqb;\frac{3\mathrm{\&pi;}}{2}-\mathrm{\&beta;}-\arcsin \left(\frac{L_1\sin \mathrm{\&alpha;}}{L_2}\right)\&rsqb;\&CenterDot;L_4\end{array}\right.$

Wherein, angle when angle [alpha] is described first connecting rod original state and between car body longitudinal centre line, span is

Angle beta is the angle between described third connecting rod and described double leval jib, and angle beta is constant;

B, constantly adjust length value L ₁, L ₂, L ₃, L ₄and angle β value, make the movement locus of leading section each point get around obstruction;

C, when the movement locus of double leval jib leading section, left and right each point can get around obstruction, length value L now ₁, L ₂, L ₃, L ₄and angle β value is end value;

D, by length value L ₁, L ₂, L ₃end value substitute into following formula, calculate the movement locus of the tie point D (x, y) of described third connecting rod and double leval jib,

$y=cos\&lsqb;\arcsin (\frac{L_2}{L_1\&CenterDot;L_3}\&CenterDot;x)\&rsqb;\&CenterDot;L_1+cos\&lsqb;\arcsin \left(\frac{x}{L_3}\right)\&rsqb;\&CenterDot;(L_2+L_3)$

Wherein, x span is:

E, flat shape by the movement locus determination mount pad of D point.

10. the method for designing of rail vehicle switching mechanism for front cover according to claim 9, it is characterized in that: in left and right, the bottom at the tie point D point place of described third connecting rod and double leval jib is respectively provided with roller or slide block, and described roller or slide block roll in the plane of described mount pad.