CN104455172B - Multistage pressure-limiting adjusting hydraulic buffer - Google Patents

Abstract

The invention discloses a multi-stage pressure-limiting adjustable hydraulic buffer, which includes multi-stage buffer mechanisms connected in sequence from left to right, each stage of buffer mechanism includes a cylinder, a pressure-limiting adjustable overflow valve and a piston, and The adjustable overflow valve is fixed on the left side of the cylinder body with threads; among the adjacent two-stage buffer mechanisms, the left end of the cylinder body of the buffer mechanism relatively on the right side is sealed and socketed with the right end of the cylinder body of the buffer mechanism relatively on the left side, And the cylinder body of the right buffer mechanism can move relative to the cylinder body of the left buffer mechanism to serve as the piston of the left buffer mechanism. The right end of the cylinder block is threadedly connected with the pressure plate. The invention combines multi-stage buffering with a pressure-limiting adjustable overflow valve to form a constant damping force long-stroke buffer, which prolongs the buffering stroke and collision time, and ensures maximum buffering energy consumption when the maximum acceleration is less than the design value.

Description

A Multistage Pressure Limiting Adjustable Hydraulic Shock Absorber

technical field

The invention relates to a hydraulic buffer, in particular to a multi-stage pressure-limiting adjustable hydraulic buffer.

Background technique

Automobile rear-end collision accidents on expressway often take place, and the dolly of fast travel rear-ends the large truck of slow speed travel, and the result of accident often causes the car crash of dolly. Existing automobile impact buffers can be divided into energy-consuming shock absorbers such as spring buffers, hydraulic buffers, and electromagnetic buffers. In order for the two vehicles approaching at high speed to release energy smoothly, the required resistance should not only be large and last for a long time, but also stable and controllable without being affected by speed changes.

Viscous dampers are widely used in building structures and bridge structures for energy dissipation and vibration reduction, and their damping force is large. The structure of the viscous damper generally adopts a shear valve type, as shown in Figure 1, in which 101 is a cylinder, 102 is a piston, 103 is a viscous fluid, 104 is a piston rod, and 105 is an orifice.

In a stroke time T of a car collision: W=Fs, where F is the average damping force, and s is a stroke of the damper when the car collides. The relationship between the damping force F and the piston speed can be approximately expressed as: F=cv ^α , where c is the viscosity coefficient of the damper, which is related to the size of the orifice on the piston and the ratio of the cross-sectional area of the piston; v is the ratio of the piston rod to the cross-sectional area of the piston. The relative velocity of the damper cylinder movement, in general, 0<α≤1, is an important performance index of the viscous damper, the smaller the index α, the smaller the change of the damping force within one stroke of the car collision.

In the process of car collision, the relationship between damping force and acceleration obeys Newton's second law: F=ma, where m is the mass of the small car, and a is the acceleration of the small car during the collision (assuming that the speed of the large car remains unchanged). Some studies believe that ordinary people The maximum instantaneous acceleration that can be tolerated is 5g, and g=9.8m/s ² is the acceleration due to gravity. In the process of car rear-end collision, the relationship between acceleration, velocity change and damper stroke is: 2as=Δv ² , where s is a stroke of the damper when the car collides, and a is the acceleration of the car. Assume that during the car rear-end collision, the velocity From 120km/h to 80km/h, Δv=40km/h≈11.1m/s, if a=4g is set, a stroke s=1.5m of the damper when the car collides can be obtained from the ^formula 2as=Δv2; It can be seen that the larger s is, the more beneficial it is to reduce the acceleration. However, due to the limitation of the existing mechanical manufacturing and processing technology and the limited installation space, the damper cylinder cannot be too long. Therefore, the multi-stage buffer has become the best choice. . How to reduce the index α value of the damping force in each level, and ensure that the damping force is basically kept constant between different levels, that is, during the entire collision process of the car rear-end, the maximum acceleration is kept basically constant, which is the key to buffering . For the existing viscous damper, it is close to 1, and the damping force is approximately proportional to the speed, which will lead to high acceleration at the initial stage of collision and insufficient energy consumption at the later stage. Just because of the above-mentioned reasons, there is no buffer device installed at the rear of large trucks at present, and the baffle plate installed in it can't avoid the tragic situation of car crash substantially.

Contents of the invention

In order to solve the above technical problems, the present invention provides a multi-stage pressure-limiting adjustable hydraulic buffer with simple structure, fast response, reliable operation and good buffering effect.

The technical solution of the present invention to solve the above problems is: a multi-stage pressure-limiting adjustable hydraulic buffer, including multi-stage buffer mechanisms connected in sequence from left to right, each stage of buffer mechanism includes a cylinder body, a pressure-limiting adjustable overflow The valve and piston, the pressure-limiting adjustable relief valve are fixed on the left side of the cylinder body with threads; among the adjacent two-stage buffer mechanisms, the left end of the cylinder body of the buffer mechanism relatively on the right is connected to the cylinder body of the buffer mechanism relatively on the left. The right end of the right end of the buffer mechanism is sealed and socketed, and the cylinder body of the right buffer mechanism can move relative to the cylinder body of the left buffer mechanism to serve as the piston of the left buffer mechanism. Linked to each other, the right end of the cylinder body of the rightmost buffer mechanism is threadedly connected with the pressure bearing plate.

In the above-mentioned multi-stage pressure-limiting adjustable hydraulic buffer, among the adjacent two-stage buffer mechanisms, the inner wall of the cylinder of the buffer mechanism on the left is provided with a seal seat, a seal ring, and an end cover in sequence from left to right, and the end cover It is threadedly connected with the inner wall of the cylinder of the buffer mechanism on the left side.

In the above-mentioned multi-stage pressure-limiting adjustable hydraulic buffer, a guide ring is provided on the outer wall of the left end of the cylinder body of the buffer mechanism on the right, and the guide ring is threadedly connected with the outer wall of the cylinder, and the gap between the guide ring and the inner wall of the cylinder of the buffer mechanism on the left is For cooperation, the guide ring is provided with a discharge hole.

In the above-mentioned multi-stage pressure-limiting adjustable hydraulic buffer, in the multi-stage buffer mechanism, the cross-sectional diameters of the cylinders of each buffer mechanism decrease sequentially from left to right.

In the above-mentioned multi-stage pressure-limiting adjustable hydraulic shock absorber, the pressure-limiting adjustable relief valve includes a valve body, a valve core, a spring, an adjusting nut, and an orifice. There is an axial throttle hole on the right side wall of the body, the valve core is installed in the valve body close to the throttle hole, the middle part of the valve core is provided with an oil injection hole, the right end of the spring is connected with the valve core, and the left end of the spring is connected with the adjusting nut connected, the adjusting nut is placed in the valve body and threadedly connected with the valve body.

The beneficial effects of the present invention are:

1. The present invention combines multi-stage buffering with a pressure-limiting adjustable overflow valve to form a long-stroke buffer with constant damping force, prolonging the buffering stroke and collision time, and ensuring maximum buffering energy consumption when the maximum acceleration is less than the design value;

2. The damping force of the cushioning mechanism at each level of the present invention is adjustable, and the damping force is stable and uniform during compression, and basically does not change with the speed;

3. When a collision occurs, the damping force of the buffer mechanism at each level is quickly and automatically adjusted, with fast response and no interference from other factors;

4. In the present invention, an oil injection hole is provided in the middle of the valve core, and with the use of bolts, the buffer mechanism can be filled and sealed with a high-pressure oil gun.

Description of drawings

Fig. 1 is a schematic structural diagram of a conventional viscous damper.

Fig. 2 is a structural schematic diagram of the present invention.

Fig. 3 is a structural diagram of the pressure-limiting regulating relief valve in Fig. 2 .

Fig. 4 is a cross-sectional structure diagram of the valve core in Fig. 3 .

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 2, the present invention includes four-stage buffer mechanisms connected sequentially from left to right, and each stage buffer mechanism of the first three-stage buffer mechanisms includes a cylinder body, a pressure-limiting adjustable overflow valve 3, a sealing seat 8, a sealing Ring 9 and end cover 10, wherein the second buffer mechanism and the third buffer mechanism also include guide ring 6; the fourth buffer mechanism includes fourth cylinder 15, screw plug, screw, pressure plate 16 and guide ring 6.

From left to right, the cross-sectional diameters of the buffer mechanism cylinders decrease successively, the left end of the fourth cylinder 15 is threadedly connected with the screw plug 14, and the outer wall of the left end of the fourth cylinder 15 is provided with a guide ring 6, and the guide ring 6 is connected with the fourth cylinder. The outer wall of the body 15 is threaded, the guide ring 6 is matched with the inner wall of the third cylinder 12, and the guide ring 6 is provided with a discharge hole 7, and the left end of the fourth cylinder 15 is sealed and sleeved with the right end of the third cylinder 12, and then from The right end presses the sealing seat 8, the sealing ring 9, and the end cover 10 from the right end of the third cylinder 12 in sequence, and the end cover 10 is threadedly connected with the inner wall of the third cylinder 12, and the fourth cylinder 15 can be connected to the third cylinder 12. Movement to act as the piston of the third cylinder 12. Connect the second cylinder 11 and the first cylinder 4 sequentially in the same way, and finally the right end of the fourth cylinder 15 is screwed to the pressure plate 16, and the pressure-limiting adjustable overflow valve 3 of the first buffer mechanism is connected to the Tank 1 is connected.

As shown in Figure 3, the pressure-limiting adjustable relief valve 3 includes a valve body 21, a spool 22, a spring 20, an adjusting nut 19 and an orifice 18, and the valve body 21 has a semi-closed opening on the left side, There is an axial throttling hole 18 on the right side wall of the valve body 21, and the valve core 22 is installed in the valve body 21 close to the throttle hole 18, as shown in FIG. The right end of the spring 20 is connected to the valve core 22 , the left end of the spring 20 is connected to the adjusting nut 19 , and the adjusting nut 19 is placed in the valve body 21 and threaded with the valve body 21 .

Since the orifice 18 of the pressure-limiting regulating relief valve 3 is large, the damping force mainly depends on the preload of the spring 20 . During the compression process of the buffer, the pressure differences on both sides of the first, second and third stage buffer mechanisms are respectively: ΔP ₁ , ΔP ₂ , ΔP ₃ , and the diameters of the outer circles of the buffer cylinders at all levels are shown in Figure 2 Shown, the design damping force is F. Use equal impact force method spring preload, the specific method is as follows:

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; \&pi;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; )</span>$

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; )</span>$

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; )</span>$

According to the design requirements, the dimensions of the cylinder blocks at all levels can be determined first; by substituting into formula (a) (b) (c), the design values of ΔP ₁ , ΔP ₂ , and ΔP ₃ can be obtained in turn; by rotating the adjusting nut 19 to compress the spring 20, it can be conveniently Get the required pressure difference at all levels. Adjusting equations (a)(b)(c) can ensure that the buffer stages are compressed in sequence.

The working principle of the present invention is as follows: when the pressure bearing plate 16 is impacted, the fluid pressure in the third cylinder 12 increases, and when the pressure difference between it and the pressure in the second cylinder 11 exceeds the limit value, the pressure limit of the third stage buffer mechanism The spring 20 of the adjustable relief valve 3 is compressed, and the fluid flows from the third cylinder 12 through the gap between the valve core 22 and the valve body 21 into the second cylinder 11; the fluid pressure in the second cylinder 11 increases, when When the pressure difference between it and the first cylinder 4 exceeds the limit value, the spring 20 of the pressure-limiting adjustable relief valve 3 of the second-stage buffer mechanism is compressed, and the fluid flows from the second cylinder 11 through the valve core 22 and the valve body. The gap between 21 enters the first cylinder 4; the fluid pressure in the first cylinder 4 increases, and when the pressure difference between it and the atmospheric pressure exceeds the limit value, the spring 20 of the pressure-limiting adjustable overflow valve 3 of the second-stage buffer mechanism Compressed, the fluid flows from the first cylinder 4 through the gap between the valve core 22 and the valve body 21 and enters the oil tank 1 . Through the prototype test, the damping force curve of each stage of the pressure-limiting adjustable buffer is α≈0.13, and the hysteretic curve of the damping force is approximately rectangular.

Claims (4)

1. A multi-stage pressure-limiting adjustable hydraulic shock absorber, characterized in that: it comprises a multi-stage buffer mechanism connected sequentially from left to right, and each stage of buffer mechanism includes a cylinder body, a pressure-limiting adjustable overflow valve and a piston, The pressure-limiting adjustable relief valve is fixed on the left side of the cylinder body with threads; among the adjacent two-stage buffer mechanisms, the left end of the cylinder body of the buffer mechanism relatively on the right is sealed with the right end of the cylinder body of the buffer mechanism relatively on the left. connected, and the cylinder body of the right buffer mechanism can move relative to the cylinder body of the left buffer mechanism to serve as the piston of the left buffer mechanism. The right end of the cylinder body of the cushioning mechanism is threadedly connected with the pressure bearing plate. The pressure-limiting adjustable relief valve includes a valve body, a valve core, a spring, an adjusting nut and an orifice. The valve body is semi-closed with a left opening, There is an axial throttling hole on the right side wall of the valve body, the valve core is installed in the valve body close to the throttle hole, the middle part of the valve core is provided with an oil injection hole, the right end of the spring is connected with the valve core, and the left end of the spring is connected with the regulating valve. Nut connection, the adjusting nut is placed in the valve body and is threadedly connected with the valve body. 2. The multi-stage pressure-limiting adjustable hydraulic buffer according to claim 1, characterized in that: among the adjacent two-stage buffer mechanisms, the inner wall of the cylinder of the buffer mechanism on the left side is provided with sealing seats sequentially from left to right , a sealing ring, and an end cap, and the end cap is threadedly connected with the inner wall of the cylinder of the buffer mechanism on the left side. 3. The multi-stage pressure-limiting adjustable hydraulic buffer as claimed in claim 2, characterized in that: in the adjacent two-stage buffer mechanism, a guide ring is provided on the outer wall of the left end of the cylinder body of the right buffer mechanism, and the guide ring and The outer wall of the cylinder is threaded, the guide ring is matched with the inner wall of the cylinder of the buffer mechanism on the left side, and the guide ring is provided with a discharge hole. 4. The multi-stage pressure-limiting adjustable hydraulic buffer according to claim 2, characterized in that: in the multi-stage buffer mechanism, the cross-sectional diameters of the buffer cylinders decrease sequentially from left to right.