A proportional positioning device and method for a fifth wheel

Abstract

The present invention discloses a proportional positioning device and method for a traction seat, which belongs to the field of fixture technology. In actual production, the positioning is accurate and does not require multiple adjustments. Positioning can be completed by clamping once. The present invention has the ability of conformal positioning. The left and right ends are fed simultaneously during the positioning process, and the feeding distance is kept at a fixed ratio. It can adapt to the deviation of the blank, and has the ability to compensate for daily wear and tear, and can provide stable and reliable positioning accuracy; while positioning, it has a clamping effect, which can weaken the deformation and vibration of the traction seat, and improve the problem of excessive tolerances in size, shape and position tolerances, and surface roughness. It fundamentally solves the problem of excessive tolerances or even scrapping of workpieces caused by inaccurate positioning, deformation, and vibration, greatly improves product quality and stability, and improves the yield rate. At the same time, it shortens the clamping time of the workpiece, greatly improves production efficiency, and improves the labor intensity of workers. The operation is simple and convenient, saving time and effort. It reduces costs and increases efficiency while improving product market competitiveness.

Description

Technical Field

[0001] The invention belongs to the technical field of clamps, and in particular relates to a proportional positioning device and method applied to a fifth wheel. Background Art

[0002] A fixture is a device used to fix the object to be processed in the mechanical manufacturing process so that it occupies the correct position for construction or inspection. It is also called a fixture (qiǎjǜ). In a broad sense, any device used to quickly, conveniently and safely install the workpiece in any process can be called a fixture. A fixture usually consists of a positioning element to determine the correct position of the workpiece in the fixture, a clamping device, a tool guide element to determine the relative position of the tool and the workpiece or guide the direction of the tool, and a dividing device so that the workpiece can complete the processing of several stations in one installation. There are two types of rotary dividing devices and linear moving dividing devices, connecting elements, clamp bodies, fixture bases, etc. Modern fixtures are developed in the direction of speed, precision and automation.

[0003] The fifth wheel is a key part used by heavy trucks to tow trailers. During the production process of the fifth wheel, the casting blank is rough and has large deviations in appearance. The deviations between different batches are even greater. The larger the size of the blank, the more obvious the deviation. The fifth wheel blank is a large multi-structure thin-walled feature casting with complex shape. The above problems are more prominent, resulting in deviations in the clamping position during the actual production process, and problems such as deformation and vibration during clamping and machining. Especially when used in new energy heavy trucks, the lightweight requirements are higher; multiple elements need to be machined in different directions, especially the boring accuracy requirements for concentric holes on both sides are high. Therefore, higher requirements are placed on positioning accuracy.

[0004] In current production, the following two methods are used to position the fifth wheel: 1) fixing the support points (limit points) at both ends; 2) fixing the support point (limit point) at one end and floating the other end for clamping.

[0005] Method 1) The support points (limit points) at both ends are fixed, and they do not have the ability to follow the shape of the workpiece blank, and do not have the clamping ability. The limit is not complete, there will be gaps in actual production, and the deviations between different batches of blanks are large, which will cause the support gap to become larger or the workpiece cannot be placed in the correct position. Readjustment is required when producing different batches of blanks.

[0006] Method 2) One end has a fixed support point (limit point) and the other end is floating. It has clamping ability and complete limit, but it brings new problems. The entire workpiece deviates to one end, and the workpiece positioning cannot be fully guaranteed. A larger processing allowance needs to be reserved during the blank casting stage. And it cannot completely avoid the problem of needing to readjust when producing different batches of blanks.

[0007] At present, both positioning methods have different degrees of inaccurate positioning, easy deformation and vibration during clamping and machining. The above two problems require multiple adjustments according to batches, which wastes time and energy. Method 2) weakens the problem of easy deformation and vibration during clamping and machining in method 1), but at the same time brings new problems: it is necessary to reserve a larger processing allowance in the blank casting stage, which not only leads to material waste, but also increases processing costs (energy consumption, equipment and tool loss, etc.), and leads to labor and time waste; due to the heavy weight of parts, multiple adjustments and clamping increase labor intensity, and the physical strength of labor is limited, which often becomes a bottleneck in improving production capacity and beat, and cannot meet the requirements of large-scale and short-cycle supply; quality reliability cannot be fully guaranteed, and the yield rate can only be slightly improved, which cannot bring about qualitative changes. The generation of scrapped products and returns brings greater waste, reduces production efficiency, and pushes up production costs, which is contrary to the development direction of lightweight and lean production ideas, and is not conducive to market development. Summary of the invention

[0008] In view of the above problems, the present invention provides a proportional positioning device and method for a traction seat, which fundamentally solves the following two problems: 1. the problem of inaccurate positioning; 2. the problem of easy deformation and vibration during clamping and machining. In actual production, the positioning is accurate and does not require multiple adjustments. Accurate positioning can be completed by clamping once. The present invention has the ability of shape-following positioning. The left and right ends are fed simultaneously during the positioning process, and the feeding distance is kept at a fixed ratio. It can adapt to the deviation of the blank, have the ability to compensate for daily wear, and can provide stable and reliable positioning accuracy; while positioning, it has a clamping effect, which can weaken the clamping deformation of the traction seat blank as a large multi-structure thin-walled feature casting and the deformation and vibration of parts during processing, and improve the problem of size, shape and position tolerance and surface roughness out-of-tolerance caused by deformation and vibration. It fundamentally solves the problem of workpiece out-of-tolerance or even scrapping caused by inaccurate positioning, deformation and vibration, greatly improves product quality and stability, improves the yield rate, and reduces the workpiece clamping time, greatly improves production efficiency, and improves the labor intensity of workers. The operation is simple and convenient, saving time and effort. While reducing costs and increasing efficiency, it improves the market competitiveness of products.

[0009] The technical solution of the present invention is as follows: a proportional positioning device applied to a traction seat, comprising: a positioning seat, a limiting flange, a positioning nut, a pressure rod, a slider, a first push rod, a second push rod and a reset spring;

[0010] The positioning seat is provided with two through circular inner holes, the axes of the two through circular inner holes are located in the same plane and are perpendicular to each other, one of the circular inner holes is provided with keyways at the top and bottom, and the other circular inner hole is provided with internal threads at both ends;

[0011] In the circular inner hole provided with a keyway, the limiting flange, the pressure rod and the sliding block are coaxially arranged;

[0012] In a circular inner hole provided with an internal thread, a positioning nut, a first push rod and a second push rod are coaxially arranged;

[0013] The limit flange is installed at one end of the circular inner hole with a key slot, the pressure rod passes through the limit flange and is fixedly connected to the slider, the slider is provided with inclined surfaces on both sides, and guide flat keys are provided on both sides different from the inclined surfaces, the guide flat keys are fixed on the slider and slide in the key slot of the circular inner hole;

[0014] The positioning nut is arranged at both ends of the circular inner hole with internal threads through threaded connection, and the first push rod and the second push rod have an arc surface at one end and an inclined surface at the other end, passing through the positioning nut, with the arc surface end outside the positioning seat and the inclined surface end cooperating with the slider;

[0015] Furthermore, a through threaded hole is provided at a corresponding position of the axis of the circular inner hole with a keyway on the limiting flange, the pressure rod is connected to the limiting flange through threads, a T-slot is provided at one end of the slider close to the pressure rod, a flange is provided at one end of the pressure rod close to the slider, and the pressure rod is connected to the T-slot through the flange.

[0016] Furthermore, a flange is provided in the middle of the first push rod near one side of the slider, and a return spring is provided in the positioning nut. The return spring is sleeved on the first push rod, and both ends of the return spring respectively abut against the end surface of the first push rod flange away from the slider and the end surface of the inner hole of the positioning nut; the second push rod adopts the same setting.

[0017] A proportional positioning method for a traction seat comprises the following steps: arranging a proportional positioning device between the inner crotch of the traction seat, and positioning the traction seat according to a fixed proportion P of the inner crotch of the traction seat or a feed distance proportion Q.

[0018] Furthermore, the traction seat inner crotch fixed ratio P is calculated by the formula

[0019]

[0020] Calculation, where Δm is the length deviation of the first side of the inner crotch of the traction seat, and Δn is the length deviation of the second side of the inner crotch of the traction seat; Δm is calculated by the formula Δm=Δh·tan a, and Δn is calculated by the formula Δn=Δh·tan b; where Δh is the height deviation, ∠a is the angle of the first side of the inner crotch of the traction seat, and ∠b is the angle of the second side of the inner crotch of the traction seat.

[0021] Furthermore, the feed distance ratio Q is given by the formula

[0022]

[0023] Calculation, where Δe is the feed distance of the first push rod, Δf is the feed distance of the second push rod, Δe is calculated by the formula Δe=Δl·tan c; Δf is calculated by the formula Δf=Δl·tan d; where Δl is the feed distance of the slider, ∠c is the inclined angle of the first side of the slider, and ∠d is the inclined angle of the second side of the slider.

[0024] The beneficial effects of the present invention are:

[0025] The device of the present invention can accurately position in actual production without multiple adjustments. It can complete positioning by clamping once. At the same time, it has a clamping effect, which can reduce the deformation of the traction seat blank as a large multi-structure thin-walled feature casting during clamping and the deformation and vibration of parts during processing, and improve the problem of size, shape and position tolerance and surface roughness out-of-tolerance caused by deformation and vibration. It fundamentally solves the problem of workpiece out-of-tolerance and even scrap caused by inaccurate positioning and deformation, greatly improves product quality and stability, and reduces the workpiece clamping time, greatly improves production efficiency, and improves the labor intensity of workers. It is simple and convenient to operate, saving time and effort. It reduces costs and increases efficiency while improving product market competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the front view of the device of the present invention.

[0027] Figure 2 for Figure 1 AA section view.

[0028] Figure 3 for Figure 1 BB cross-section view.

[0029] Figure 4 The figure is a schematic diagram of the device of the present invention applied to a fifth wheel clamp.

[0030] Figure 5 for Figure 4 Left view.

[0031] Figure 6 This is a simplified schematic diagram of the deviation of the fifth wheel blank.

[0032] Figure 7 Simplified schematic for the proportional positioning method.

[0033] In the figure:

[0034] 1-clamp body assembly; 2-proportional positioning device (device of the present invention); 3-traction seat; 103-predetermined support plate; 104-first pressure plate; 105-second pressure plate; 106-pressing screw; 201-positioning seat; 202-limiting flange; 203-positioning nut; 204-pressure rod; 205-sliding block; 206-guide flat key; 207-first push rod; 208-second push rod; 209-reset spring; 301-traction seat inner crotch A slope; 302-the second slope of the inner crotch of the traction seat; 303-the reference plane of the traction seat; ∠a-the first side angle of the inner crotch of the traction seat; ∠b-the second side angle of the inner crotch of the traction seat; Δh-height deviation; Δm-the first side length deviation of the inner crotch of the traction seat; Δn-the second side length deviation of the inner crotch of the traction seat; ∠c-the first side slope angle of the slider; ∠d-the second side slope angle of the slider; Δl-slider feeding distance; Δe first push rod feeding distance; Δf second push rod feeding distance. DETAILED DESCRIPTION

[0035] It should be noted that in the description of the present invention, the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise", "counterclockwise", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction.

[0036] In the present invention, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connect" and the like should be understood in a broad sense. For example, "fixed" can be a fixed connection, a detachable connection, or an integral connection; the connection can be a mechanical connection or an electrical connection; the connection can be a direct connection or an indirect connection through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the current mechanical processing, the structure of parts is becoming more and more complex, the size requirements are strict, the lightweight requirements are becoming higher and higher, and the requirements for production equipment and fixtures are becoming higher and higher. The present invention is a proportional positioning device and method applied to the fifth wheel, which is applied to the fifth wheel machine fixture (tooling) as a key positioning unit.

[0038] There are many kinds of products (traction seats) currently in actual production. The figure shows one of them as an example. The traction seat is only a schematic diagram, not an engineering drawing. In order to express the appearance structure of the workpiece more clearly, the structure, proportion and other details of the figure have been simplified.

[0039] The device of the present invention can completely solve the problem of positioning accuracy and fundamentally ensure positioning accuracy; it is easy to use, and positioning can be completed by clamping once without multiple adjustments in actual production; it also has a clamping effect, suppressing deformation and vibration; shortening the workpiece clamping time and improving production efficiency; improving the labor intensity of workers; it has strong versatility, and different traction seat products can be used by only replacing the corresponding slider 205, the first push rod 207, and the second push rod 208; it is easy to repair and maintain, and the wearing parts can be replaced, which greatly extends the service life of the clamp. While ensuring quality, it improves work efficiency, saves manpower and material resources, greatly reduces the generation of scrapped products, and greatly improves the yield rate. It is flexible and convenient to use, and reduces costs and increases efficiency while improving product market competitiveness.

[0040] The traction seat 3 is a workpiece or a product.

[0041] The angles of the inclined surfaces on both sides of the slider are determined according to the fixed ratio of the inner crotch of the traction seat, that is, the ratio of the feeding distances on both sides. According to the present invention, the installation position of the device in the clamp and the distances between the inner crotch of the traction seat and the center determine the lengths of the first push rod 207 and the second push rod 208 respectively.

[0042] The proportional positioning device 2 is installed and fixed on the fixture main body assembly 1 of the machined traction seat. When using this fixture, the traction seat 3 is placed on the predetermined support plate 103. Under the action of gravity, both ends are in close contact, and the traction seat reference surface is close to the predetermined support plate 103. Tighten the proportional positioning device 2 pressure rod 204 for positioning and clamping, and then clamp the traction seat 3 through the first pressure plate 104 and the second pressure plate 105 on the fixture main body assembly 1, and manually tighten the clamping screw 106. At this time, the machining center can be started to perform machining operations according to the program.

[0043] The technical solution of the present invention is as follows: a proportional positioning device of a traction seat, comprising: a positioning seat 201, a limiting flange 202, a positioning nut 203, a pressure rod 204, a slider 205, a first push rod 207, a second push rod 208 and a return spring 209;

[0044] The positioning seat 201 is provided with a circular inner hole that passes through front and back, and key slots are provided on the top and bottom of the inner hole; the positioning seat 201 is provided with a circular inner hole that passes through left and right, and the axis of the circular inner hole that passes through left and right is in the same plane as the axis of the circular inner hole that passes through front and back, and is perpendicular to each other, and threaded holes are provided at both ends of the circular inner hole that passes through left and right, as shown in FIG. Figure 3 ;

[0045] The circular inner hole of the positioning seat 201, the limiting flange 202, the pressure rod 204 and the slider 205 are all coaxially arranged;

[0046] The circular inner hole of the positioning seat 201, the positioning nut 203, the first push rod 207, the second push rod 208 and the return spring 209 are all coaxially arranged;

[0047] The limiting flange 202 is installed at the front end of the circular inner hole that passes through the front and back, and there is a threaded hole passing through the middle of the limiting flange 202;

[0048] The pressure rod 204 is connected to the limiting flange 202 by threads, and a flange is provided at the front end of the pressure rod 204;

[0049] The slider 205 is arranged in a circular inner hole that passes through the front and back. The left and right sides of the slider 205 are provided with inclined surfaces. The upper and lower sides of the slider 205 are provided with key slots for installing the guide flat key 206. The tail of the slider 205 is provided with a T-shaped slot to cooperate with the front end flange of the pressure rod 204.

[0050] The positioning nuts 203 are arranged at both ends of the circular inner hole passing through the left and right sides, and are threadedly connected to the positioning seat 201. The positioning nuts 203 on both sides are coaxially arranged, and the axis direction of the positioning nuts 203 and the axis direction of the circular inner hole passing through the positioning seat 201 are in the same plane and perpendicular to each other.

[0051] The first push rod 207 has a similar structure to the second push rod 208: the free end is an arc surface, the other end is an inclined surface, and a flange is provided in the middle near the slider;

[0052] The first push rod 207 passes through the circular inner hole on the positioning seat 201, the return spring and the left positioning nut, and is arranged on the left side of the positioning seat;

[0053] The second push rod 208 passes through the circular inner hole on the positioning seat 201, the return spring and the right positioning nut, and is arranged on the right side of the positioning seat;

[0054] There are two return springs 209, which are respectively arranged in the left and right positioning nuts 203: the left return spring is sleeved with the first push rod 207, and its two ends respectively abut against the end surface of the first push rod 207 flange away from the slider and the end surface of the inner hole of the left positioning nut; the right return spring is sleeved with the second push rod 208, and its two ends respectively abut against the end surface of the second push rod 208 flange away from the slider and the end surface of the inner hole of the right positioning nut;

[0055] Tighten the pressure rod 204, and the slider 205 is linearly driven to move backward along the axis direction in the circular inner hole of the positioning seat 201 under the action of the pressure rod 204, and the upper and lower guide flat key grooves of the slider 205 cooperate with the upper and lower key grooves of the circular inner hole of the positioning seat 201, playing a guiding and positioning role while bearing the clamping force on the left and right sides;

[0056] The first push rod 207 abuts against the left inclined surface of the slider 205, and the second push rod 208 abuts against the right inclined surface of the slider 205. The first push rod 207 and the second push rod 208 respectively keep close contact with the left and right inclined surfaces of the slider 205 at all times under the action of the left and right return springs;

[0057] The first push rod 207 and the second push rod 208 can move toward the left and right inner crotch of the workpiece (traction seat 3) respectively along the axial direction of the circular inner hole that passes through the left and right sides of the positioning seat 201 under the action of the slider 205, and successively contact the two sides of the inner crotch of the workpiece (traction seat 3) until clamped, so as to complete accurate proportional positioning and assist in clamping the workpiece (traction seat 3);

[0058] The pressure rod 204 and the limiting flange 202 are connected by threads to form a self-locking state, thereby maintaining a stable and accurate proportional positioning state.

[0059] The pressure rod 204 is released, and the slider 205 is linearly driven by the pressure rod 204 to move forward along the axis direction in the circular inner hole that passes through the positioning seat 201 from front to back;

[0060] The first push rod 207 and the second push rod 208 respectively keep close contact with the left and right inclined surfaces of the slider 205 under the action of the left and right return springs, and move toward the slider 205 along the axis direction of the circular inner hole passing through the left and right of the positioning seat 201, and relax on both sides of the inner crotch of the workpiece (traction seat 3);

[0061] A proportional positioning method for a fifth wheel comprises the following steps:

[0062] S1: Install and fix the proportional positioning device 2 on the fixture main body assembly 1;

[0063] S2: placing the traction seat 3 on the predetermined support plate 103, and placing the traction seat reference surface 303 close to the predetermined support plate 103;

[0064] S3 tightens the pressure rod 204 of the proportional positioning device 2 to clamp the inclined surfaces on both sides of the inner crotch of the traction seat;

[0065] S4 clamps the traction seat 3 by the first pressing plate 104 and the second pressing plate 105 on the clamp body assembly 1, and tightens the clamping screw 106 by hand;

[0066] S5 can start the machining center to perform machining operations on the traction seat according to the program.

[0067] According to the characteristics of the casting and previous production experience: the angles of the traction seat reference surface and the left and right sides of the traction seat inner crotch are relatively stable and can be used as reliable positioning positions.

[0068] The traction seat 3 is positioned by the clamp body assembly 1, which constrains five of the six degrees of freedom: movement along the Y-axis direction, movement along the Z-axis direction, movement around the X-axis direction, movement around the Y-axis direction, and movement around the Z-axis direction. The sixth degree of freedom is constrained by the proportional positioning device 2: movement along the X-axis direction, and is arranged between the left and right inner crotches of the traction seat.

[0069] When positioning the traction seat blank, there will be deviations in the positioning of different blanks, such as Figure 6 :

[0070] Angle ∠a of the first side of the inner crotch of the traction seat;

[0071] Angle ∠b of the second side of the inner crotch of the traction seat;

[0072] Take the height deviation as Δh;

[0073] Take the length deviation of the first side of the inner crotch of the traction seat Δm;

[0074] Take the length deviation Δn of the second side of the inner crotch of the traction seat;

[0075] Δm=Δh×tan a;

[0076] Δn=Δh×tan b;

[0077] The length deviation of the first side of the inner crotch of the traction seat and the length deviation of the second side of the inner crotch of the traction seat are taken as the fixed ratio P of the inner crotch of the traction seat. This requires that the left and right sides of the inner crotch of the traction seat are fed at the same time. During the entire process of positioning and clamping, the feeding distance of the first side of the inner crotch of the traction seat and the feeding distance of the second side of the inner crotch of the traction seat always maintain a fixed ratio P.

[0078]

[0079] According to a proportional positioning method described in the present invention, the simplified principle is as follows Figure 7 :

[0080] Angle ∠c of the inclined surface of the first side of the slider;

[0081] The included angle ∠d of the second side inclined surface of the slider;

[0082] Take the slider feed distance as Δl;

[0083] Take the first ejector feed distance Δe;

[0084] Take the second ejector feed distance Δf;

[0085] Δe=Δl×tan c;

[0086] Δf = Δl × tan d;

[0087]

[0088] The ratio of the feeding distance of the first push rod to the feeding distance of the second push rod is Q. If Q=P, the proportional positioning method of the fifth wheel can be used to achieve proportional positioning of the fifth wheel. It can be deduced that:

[0089]

[0090] Mechanical self-locking principle:

[0091] μ ≥ tanθ;

[0092] μ is the static friction coefficient;

[0093] θ is the self-locking friction angle;

[0094] If the application environment has high requirements for the reliability of positioning and clamping, such as long-term clamping or working in a vibrating environment, the angle of the inclined surface on both sides of the slider can be less than or equal to the self-locking friction angle θ. At this time, the first push rod and the left inclined surface of the slider form a self-locking; the second push rod and the right inclined surface of the slider form a self-locking; the pressure rod and the limit flange are threaded to form a self-locking; the proportional positioning device has a high degree of stability.

[0095] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent replacement and improvement made by any person skilled in the art within the technical scope disclosed by the present invention and within the spirit and principle of the present invention shall be covered within the protection scope of the present invention. At the same time, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0096] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

Claims

1. A proportional positioning device applied to a fifth wheel, characterized in that: include: A positioning seat, a limiting flange, a positioning nut, a pressure rod, a slider, a first push rod, a second push rod and a return spring; The positioning seat is provided with two through circular inner holes, the axes of the two through circular inner holes are located in the same plane and are perpendicular to each other, one of the circular inner holes is provided with keyways at the top and bottom, and the other circular inner hole is provided with internal threads at both ends; In the circular inner hole provided with a keyway, the limiting flange, the pressure rod and the sliding block are coaxially arranged; In a circular inner hole provided with an internal thread, a positioning nut, a first push rod and a second push rod are coaxially arranged; The limit flange is installed at one end of the circular inner hole with a key slot, the pressure rod passes through the limit flange and is fixedly connected to the slider, the slider is provided with inclined surfaces on both sides, and guide flat keys are provided on both sides different from the inclined surfaces, the guide flat keys are fixed on the slider and slide in the key slot of the circular inner hole; The positioning nuts are arranged at both ends of a circular inner hole with an internal thread through a threaded connection. The first push rod and the second push rod have an arc surface at one end and an inclined surface at the other end, and pass through the positioning nuts. The arc surface end is outside the positioning seat, and the inclined surface end cooperates with the slider. The inclined surface angles on both sides of the slider are determined according to the fixed ratio of the inner crotch of the traction seat, that is, the ratio of the feed distance on both sides. The lengths of the first push rod and the second push rod are determined according to the installation position of the proportional positioning device in the fixture and the distance between the two sides of the inner crotch of the traction seat and the center.

2. A proportional positioning device for a fifth wheel as claimed in claim 1, characterized in that: The limiting flange is provided with a through threaded hole at the corresponding position of the axis of the circular inner hole with a keyway, the pressure rod is connected to the limiting flange through threads, the slider is provided with a T-slot at one end close to the pressure rod, and the pressure rod is provided with a flange at one end close to the slider, and the pressure rod is connected to the T-slot through the flange.

3. A proportional positioning device for a fifth wheel as claimed in claim 1, characterized in that: A flange is provided in the middle of the first push rod near the slider, and a reset spring is provided in the positioning nut. The reset spring is sleeved on the first push rod, and the two ends of the reset spring respectively abut against the end surface of the first push rod flange away from the slider and the end surface of the inner hole of the positioning nut; the second push rod adopts the same setting.

4. A proportional positioning method applied to a fifth wheel, characterized in that: The following steps are involved: Arrange the device as claimed in any one of claims 1 to 3 between the inner crotch of the traction seat, and position the traction seat according to the fixed ratio P of the inner crotch of the traction seat or the feed distance ratio Q, wherein the fixed ratio P of the inner crotch of the traction seat is determined by the formula Calculation, where Δm is the length deviation of the first side of the inner crotch of the traction seat, and Δn is the length deviation of the second side of the inner crotch of the traction seat; Δm is calculated by the formula Calculate, Δn by the formula Calculation; where Δh is the height deviation, ∠a is the first side angle of the inner crotch of the traction seat, ∠b is the second side angle of the inner crotch of the traction seat, and the feed distance ratio Q is calculated by the formula Calculate, where Δe is the first ejector feed distance, Δf is the second ejector feed distance, and Δe is calculated by the formula Calculation; Δf is calculated by the formula Calculation; where Δl is the slider feed distance, ∠c is the slider first side slope angle, and ∠d is the slider second side slope angle.

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