A performance test bench for automobile anti-lock braking system

Abstract

The invention discloses a vehicle anti-lock braking system performance test bench, comprising a fixed front test bench and a rear test bench that can move forward and backward, the front test bench is provided with left front and right front test units, and the rear test bench is provided with left rear and right rear test units; the number of the main and auxiliary roller center distance adjustment mechanism is two sets, the left front and right front test units share one set, and the left rear and right rear test units share one set; the test unit comprises a main roller and an auxiliary roller, and the auxiliary roller can be adjusted in front and back positions under the action of the main and auxiliary roller center distance adjustment mechanism and a reset spring; under the drive of a second motor, the center distances of two pairs of main and auxiliary rollers on the same test bench can also be adjusted in reverse; a flywheel mechanism with adjustable motion inertia is provided on the rotating shaft of the main roller. The invention adjusts the center distance of the main and auxiliary rollers to adjust the placement angle, thereby changing the adhesion coefficient, and the test result is accurate, the cost is low, the durability is good, and the vehicle ABS performance regular test of a large number of vehicles in use can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile braking performance detection, and in particular relates to an automobile anti-lock braking system performance detection platform. Background Art

[0002] Automobiles need to be tested for braking performance regularly to ensure driving safety. The general reaction-type roller brake test bench usually tests vehicle speeds within 10km / h, while the vehicle anti-lock braking system (ABS) takes effect at a speed of at least 20km / h. Therefore, this type of test bench can only test conventional braking performance, but not ABS performance.

[0003] Among the known ABS performance testing devices, CN101470049B discloses an anti-lock braking system dynamic simulation test bench based on a magnetic powder clutch, which realizes the dynamic simulation of the adhesion coefficient between the tire and the road surface by adjusting the excitation current of the magnetic powder clutch. There are the following technical problems: (1) It does not have the whole vehicle testing function; (2) The magnetic powder clutch is expensive and easily damaged during high-load testing operations, resulting in a high comprehensive cost and poor durability of the automobile ABS brake test bench based on the magnetic powder clutch; (3) The wheel placement angle cannot be adjusted, resulting in the test result being affected by the wheel size and inaccurate. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a vehicle anti-lock braking system performance test bench with low cost, good durability and accurate test results, which can meet the needs of regular ABS testing of a large number of vehicles in use.

[0005] Technical solution: The automobile anti-lock braking system performance test bench described in the present invention includes four detection units corresponding to the wheels one by one, and the detection units include a main roller, a secondary roller and a main and secondary roller center distance adjustment mechanism; the rotating shaft of the main roller is installed on two second bearing seats, and the rotating shaft of the secondary roller is installed on two first bearing seats, the second bearing seats are fixedly arranged, and the first bearing seats are slidably arranged on the first guide rail therebelow; the rotating shafts of the main and secondary rollers are dynamically connected through a sprocket chain with a tensioning mechanism; the first and second bearing seats are connected through a reset spring, and the secondary roller can achieve front and rear position adjustment under the action of the main and secondary roller center distance adjustment mechanism and the reset spring.

[0006] In the present invention, the installation angle is adjusted by adjusting the center distance between the main and auxiliary rollers, thereby changing the adhesion coefficient between the wheel and the roller, so as to realize the anti-lock braking performance detection under different road conditions, including single low adhesion coefficient, single high adhesion coefficient, split road surface and butt road surface. The adjustable installation angle makes the detection result more accurate. In addition, compared with the technical solution of using magnetic powder clutch, the present invention has low cost and good durability, and can meet the regular vehicle ABS performance detection of a large number of vehicles in use.

[0007] Furthermore, there are two sets of the main and auxiliary roller center distance adjustment mechanisms, one set is shared by the left front and right front detection units, and the other set is shared by the left rear and right rear detection units; the two first bearing seats are connected by a connecting rod; the main and auxiliary roller center distance adjustment mechanisms include a plate that can be moved forward and backward, and a third sprocket is provided on the plate, and the third sprocket is located on the left-right symmetrical center plane of the detection platform; the second chain meshingly arranged on the third sprocket, and its two ends are respectively connected to the two connecting rods after passing around the fixed second sprocket.

[0008] When the plate moves forward and backward, the second chain pulls the connecting rod backward, so that the center distance between the main and auxiliary rollers of the two detection units can be increased at the same amplitude, or the center distance between the main and auxiliary rollers of the two detection units can be reduced at the same amplitude under the joint action of the reset spring and the tensioning mechanism. This can adapt to the detection requirements of suitable placement angles of wheels of different vehicles under inspection and realize the simulation of two coaxial wheels running on a road with the same adhesion coefficient.

[0009] Further, the third sprocket is mounted on the output shaft of the second motor, and the second motor is arranged on the plate.

[0010] When the second motor rotates, the second chain pulls the connecting rod on one side connected to it, so that the center distance between the main and auxiliary rollers on this side increases; the second chain on the other side is relaxed, and under the joint action of the return spring and the tensioning mechanism on the other side, the center distance between the main and auxiliary rollers on the other side decreases, thereby realizing the reverse adjustment of the center distances between the main and auxiliary rollers of the two detection units, so that the two coaxial wheels can simulate running on roads with different adhesion coefficients. In the present invention, the center distances of the four main and auxiliary rollers can be adjusted, which can meet the ABS performance detection needs of different wheels on roads with different adhesion coefficients.

[0011] Furthermore, a flywheel mechanism with adjustable motion inertia is provided on the rotating shaft of the main drum, which can simulate the motion inertia of different vehicle models during braking.

[0012] Furthermore, the flywheel mechanism includes a large flywheel, a middle flywheel and a small flywheel which are arranged in sequence from the main roller to the left-right symmetrical center plane of the detection platform, wherein the large flywheel and the middle flywheel are provided with an electromagnetic clutch; in the two detection units on the same side of the front and rear, the rotating shafts of the two main rollers are connected by a second electromagnetic clutch.

[0013] In this technical solution, two sets of flywheel mechanisms can generate eight different motion inertias for selection based on multiple electromagnetic clutches, which can meet the needs of inertia simulation for large, medium and small vehicles with large differences in motion inertias. At the same time, in addition to being able to meet the ABS performance test, the left and right wheels of the present invention can also be independently tested, meeting the national standard for the test requirements of conventional automobile braking performance, and having strong applicability.

[0014] Furthermore, the above-mentioned automobile anti-lock braking system performance test bench also includes a fixed front test bench and a rear test bench that can move forward and backward, the left front and right front test units are arranged on the front test bench, and the left rear and right rear test units are arranged on the rear test bench; the auxiliary roller shaft of the right front test unit is connected to the speed reduction mechanism through the third electromagnetic clutch, and the speed reduction mechanism is connected to the first transmission shaft through the coupling; the auxiliary roller shaft of the right rear test unit is connected to the speed increase mechanism, and the speed increase mechanism is connected to the second transmission shaft through the coupling; the first transmission shaft is provided with an external spline, and the second transmission shaft has an internal spline, and the first transmission shaft is plugged and connected with the second transmission shaft. This technical solution can meet the braking performance test requirements of vehicles with different wheelbases by adjusting the distance between the front and rear test benches.

[0015] Furthermore, the detection unit also includes a wheel protection mechanism, which includes a vertical plate, which can move left and right on the cover plates at the outer ends of the main and auxiliary rollers; seat holes are provided at the front, rear and upper ends of the vertical plate, and a bent support shaft is inserted in the seat hole. A rolling sleeve is provided on the support shaft to press against the wheel to prevent the wheel from moving forward, backward, upward or sideways during braking, thereby improving the detection safety and the accuracy of the detection results.

[0016] Furthermore, the seat hole is a long hole, and the position of the support shaft in the seat hole is adjustable. During specific operation, it can be adjusted according to different wheelbases and wheel sizes of different cars, and has strong applicability.

[0017] Furthermore, a wheel-in-place and roller locking mechanism is provided between the main and auxiliary rollers, and the wheel-in-place and roller locking mechanism includes an intermediate roller and a lifting plate, and both ends of the intermediate roller are supported by support arms; a spring and a travel switch are installed under the support arm; a lifting cylinder is installed between the main and auxiliary rollers near the main roller to drive the lifting plate to move up and down; a roller locking belt is installed between the lifting plate and the main roller mounting frame, and the roller locking belt passes around the bottom of the main roller.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: by adjusting the center distance between the main and auxiliary rollers to adjust the placement angle, the adhesion coefficient between the wheel and the roller is changed, the detection result is accurate, the detection table has low cost and good durability, and can meet the regular vehicle ABS performance detection needs of a large number of vehicles in use. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the force diagram of the wheel on the roller;

[0020] Figure 2 It is a schematic diagram of the structure of the present invention;

[0021] Figure 3 It is a structural diagram of the wheel in place and roller locking mechanism;

[0022] Figure 4 It is a schematic diagram of the structure of the middle roller end;

[0023] Figure 5 It is a structural schematic diagram of the tensioning mechanism;

[0024] Figure 6 It is a structural diagram of the wheel protection mechanism. DETAILED DESCRIPTION

[0025] There are many components in the present invention. To facilitate understanding of the technical solution, the accompanying drawings are listed as follows.

[0026] 1-first guide rail; 2-connecting rod; 3-first bearing seat; 4-reset spring; 5-first electromagnetic clutch; 6-speed reducer; 7-force measuring motor; 8-force measuring lever; 9-force measuring sensor; 10-second bearing seat; 11-main roller; 12-lifting plate; 13-vehicle speed sensor; 14-first sprocket; 15-large flywheel; 16-active friction plate; 17-driven friction plate; 18-slip ring; 19-middle flywheel; 20-small flywheel; 21-wheel speed sensor; 22-first chain; 23-armature; 24-electromagnetic coil; 25-iron core; 26-speed reduction mechanism; 27-coupling; 28-first transmission shaft; 29-second sprocket; 30-second chain; 31-first motor; 32-plate; 33-first rack; 34-first gear; 35-third sprocket; 36-second motor; 37-auxiliary roller; 38-middle roller; 39-speed increasing mechanism; 40-second guide rail; 41-third motor; 42-second rack; 43-second gear; 44-rear detection stand; 45-roller locking belt; 46-lifting cylinder; 47-spring; 48-travel switch; 49-pulse signal through hole; 50-support arm; 51-fixed tension wheel; 52-movable tension wheel; 53-weight block; 54-rolling sleeve; 55-vertical plate; 56-support shaft; 57-seat hole; 58-bottom plate; 59-third guide rail; 60-second electromagnetic clutch; 61-third electromagnetic clutch.

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0028] The principle of the present invention is: Figure 1As shown, the magnitude of the braking force applied by the wheel on the main and auxiliary rollers is equal to the force F1 and F2 applied by the main and auxiliary rollers on the wheel. Since N1cosα+N2cosα=G, F1=N1f, F2=N2f, F1+F2=Gf / cosα, where N1 and N2 are the supporting reaction forces of the wheel on the roller, α is the wheel placement angle, G is the wheel weight, and f is the adhesion coefficient between the wheel and the roller. If the wheel placement angle α is increased, the braking force (F1+F2) that can be measured by the test bench will increase accordingly, and vice versa. And α=arcsin(L / (D+d)), where L is the center distance between the main and auxiliary rollers, D is the wheel diameter, and d is the roller diameter. When the vehicle under test is known and the measured braking force remains unchanged, the adhesion coefficient f between the wheel and the roller can be changed by adjusting the center distance L of the main and auxiliary rollers to simulate the anti-lock braking performance test of the car on roads with different adhesion coefficients.

[0029] like Figure 2 As shown, a vehicle anti-lock braking system performance test bench includes a front test bench and a rear test bench 44. A left front test unit and a right front test unit are symmetrically arranged on the front test bench, and a left rear test unit and a right rear test unit are symmetrically arranged on the rear test bench 44. The left front and right front test units share a set of main and auxiliary roller center distance adjustment mechanisms, and the left rear and right rear test units share a set of main and auxiliary roller center distance adjustment mechanisms. The two sets of main and auxiliary roller center distance adjustment mechanisms are respectively arranged on the corresponding test benches. The left front test unit and the right front test unit have the same structure. The left rear test unit and the right rear test unit have the same structure, which is slightly different from the left front and right front test units. The structure of the test unit is specifically introduced below, taking the left front test unit as an example.

[0030] The left front detection unit includes a first electromagnetic clutch 5, a force measuring motor 7, a main roller 11 and a secondary roller 37. The rotating shaft of the main roller 11 is installed on two second bearing seats 10, and the rotating shaft of the secondary roller 37 is installed on two first bearing seats 3. The second bearing seat 10 is fixed on the front detection stand. The first bearing seat 3 is slidably arranged on the first guide rail 1 below it, and the first guide rail 1 is fixed on the front detection stand. The force measuring motor 7 is connected to the active part of the first electromagnetic clutch 5 through the reducer 6, and the driven part of the first electromagnetic clutch 5 is connected to the rotating shaft of the main roller 11. A force measuring lever 8 is fixedly connected to the housing of the reducer 6, and a force measuring sensor 9 is installed at the lower part of the outer end of the force measuring lever 8. A reset spring 4 is installed between the first bearing seat 3 and the second bearing seat 10 on the outer side of the main and secondary rollers. A rotating gear is installed on the rotating shaft between the second bearing seat 10 on the inner side of the main roller 11 and the end face of the main roller 11, and a vehicle speed sensor 13 is correspondingly provided on the outer side of the rotating gear. The first sprocket 14 is installed on the second bearing seat 10 inside the main and auxiliary rollers and the rotating shaft at the outer end of the first bearing seat 3 respectively. The two first sprockets 14 are connected by a first chain 22, and a tensioning mechanism is provided on the first chain 22. Figure 5 As shown, the tensioning mechanism includes two fixed tensioning wheels 51 and one movable tensioning wheel 52. The two fixed tensioning wheels 51 are arranged below the first chain 22 to support the first chain 22. The movable tensioning wheel 52 is arranged on the inner side of the first chain 22 and is located between the two fixed tensioning wheels 51. A weight block 53 is connected to the rotating shaft of the movable tensioning wheel 52 through a support rod.

[0031] The two first bearing seats 3 are connected by a connecting rod 2. The main and auxiliary roller center distance adjustment mechanism includes a plate 32, the longitudinal center plane of the plate 32 coincides with the left-right symmetrical center plane of the front detection stand, a first rack 33 is longitudinally installed in the middle position of the lower surface of the plate 32, a guide rail for the plate 32 to move forward and backward is provided on the front detection stand, and a first motor 31 is also fixed on the front detection stand, and the first motor 31 is located below the plate 32. A first gear 34 is installed on the output shaft of the first motor 31, and the first gear 34 is meshed with the first rack 33. A second motor 36 is installed in the middle position of the upper surface of the plate 32, and the output shaft of the second motor 36 is fixedly connected to the third sprocket 35 by a single key, and the third sprocket 35 is meshed with a second chain 30, and after the two ends of the second chain 30 pass around the second sprocket 29 fixed on the front detection stand, one end is connected to the connecting rod 2 in the left front detection unit, and the other end is connected to the connecting rod 2 in the right front detection unit.

[0032] A wheel-in-place and roller-locking mechanism is provided between the main and auxiliary rollers. Figure 3 and Figure 4 As shown, the wheel in place and roller locking mechanism includes an intermediate roller 38 and a lifting plate 12. The inner end of the intermediate roller 38 is evenly provided with a plurality of pulse signal through holes 49 along the circumferential direction. The rotating shafts at both ends of the intermediate roller 38 are supported by support arms 50. The support arms 50 are provided with wheel speed sensors 21, which are directly opposite to the pulse signal through holes 49. A spring 47 and a travel switch 48 are installed below the support arms 50. A lifting cylinder 46 is installed between the main and auxiliary rollers near the main roller 11. The lifting plate 12 is installed at the end of the piston rod of the lifting cylinder 46. A roller locking belt 45 is provided between the lower surface of the lifting plate 12 and the mounting frame of the main roller 11. The roller locking belt 45 bypasses the bottom of the main roller 11.

[0033] A flywheel mechanism is installed on the rotating shaft of the main drum 11 located outside the first sprocket 14, and the flywheel mechanism includes a large flywheel 15, a middle flywheel 19 and a small flywheel 20 which are arranged in sequence from the main drum 11 to the central plane direction of the left and right symmetry of the detection platform, wherein the large flywheel 15 and the middle flywheel 19 are provided with an electromagnetic clutch. Specifically, the large flywheel 15 and the middle flywheel 19 are loosely sleeved on the rotating shaft of the main drum 11 via rolling bearings, and the inner end of the small flywheel 20 is fixedly connected to the rotating shaft of the main drum 11 via a single key. The electromagnetic clutch of the large flywheel 15 includes an armature 23, an active friction plate 16, a driven friction plate 17, an electromagnetic coil 24, an iron core 25, a slip ring 18 and a sleeve. The armature 23 and the center of the active friction plate 16 disc are processed with internal splines, which mesh with the external splines processed at the corresponding position on the main roller 11 shaft. The center area of ​​the driven friction plate 17 disc is a through hole, and the inner splines are processed near the outer circle, which mesh with the external splines processed at the corresponding position on the sleeve. One end of the sleeve is connected to the outer circle of the large flywheel 15 by bolts. The active and driven friction plates are staggered during assembly. The electromagnetic coil 24 is installed inside the iron core 25. The inner end of the iron core 25 is fixedly connected to the main roller 11 shaft through a single key, and the outer end of the iron core 25 is equipped with a slip ring 18. The electromagnetic clutch structure of the middle flywheel 19 is similar to that of the large flywheel 15, and will not be repeated here. A second electromagnetic clutch 60 is provided between the left front detection unit and the right front detection unit to connect the rotating shafts of the two main rollers 11. When the second electromagnetic clutch 60 is powered on or off, the rotating shafts of the two main rollers 11 can be engaged or separated.

[0034] The left rear and right rear detection units are different from the left front and right front detection units in that the left rear and right rear detection units are not provided with the first electromagnetic clutch 5, the reducer 6, the force measuring motor 7, the force measuring lever 8, the force measuring sensor 9, the vehicle speed sensor 13 and the rotating gear matched with the vehicle speed sensor 13. The specific structures and connection relationships of the left rear detection unit, the right rear detection unit and the main and auxiliary roller center distance adjustment mechanism matched with the left rear and right rear detection units are not described in detail here.

[0035] The rear detection stand 44 has a substantially similar structure to the front detection stand, except that the rear detection stand 44 can move forward and backward. Specifically, second guide rails 40 are installed at the left, middle and right positions below the overall frame of the rear detection stand 44 to meet the need for the rear detection stand 44 to move forward and backward. Second racks 42 are longitudinally installed on the left and right frames of the rear detection stand 44, and a third motor 41 is provided below the rear detection stand 44. The second guide rails 40 and the third motor 41 are fixed to the ground and do not move. A second gear 43 is installed on the output shaft of the third motor 41, and the second gear 43 is meshed with the second rack 42. When the two third motors 41 under the overall frame of the rear detection stand 44 rotate, the rear detection stand 44 can be driven to move forward and backward along the second guide rails 40 as a whole, so as to meet the needs of anti-lock braking performance testing of vehicles with different wheelbases.

[0036] In the right front detection unit, the auxiliary roller 37 is located on the rotating shaft outside the first bearing seat 3 and is installed with a third electromagnetic clutch 61. The rotating shaft outside the third electromagnetic clutch 61 is installed with a speed reduction mechanism 26. The output shaft of the speed reduction mechanism 26 is connected to the first transmission shaft 28 through a coupling 27. The first transmission shaft 28 is processed with an external spline at one end close to the rear detection stand 44. In the right rear detection unit, the auxiliary roller 37 is located on the rotating shaft outside the first bearing seat 3 and is installed with a speed increase mechanism 39. The input shaft of the speed increase mechanism 39 is connected to the second transmission shaft through a coupling 27. The second transmission shaft has an internal spline. The first transmission shaft 28 is plug-connected to the second transmission shaft, and then when the rear detection stand 44 moves forward and backward, the two transmission shafts can cooperate to extend and retract. When testing the ABS performance, after the third electromagnetic clutch 61 is turned on, the rotation speed of the front and rear detection unit rollers can be kept consistent, ensuring that the speed measured by the vehicle speed sensor 13 is the running speed of the whole vehicle.

[0037] In addition, in order to prevent the wheels from moving forward, backward, upward or sideways during braking, wheel protection mechanisms are provided on the covers at the outer ends of the main and auxiliary rollers. Figure 6 As shown, the wheel protection mechanism includes a vertical plate 55, which is vertically fixed on a bottom plate 58. The bottom plate 58 is movably arranged on a third guide rail 59, which is fixed on the cover plates at the outer ends of the main and auxiliary rollers. Seat holes 57 are processed at the front, rear and upper ends of the inner surface of the vertical plate 55. The seat holes 57 are long holes, in which a support shaft 56 bent at 120° is inserted, and a rolling sleeve 54 is installed on the support shaft 56. According to different wheel tracks and wheel sizes of different vehicles, the bottom plate 58 is moved horizontally to the left and right and the position of the support shaft 56 in the seat hole 57 is adjusted, so that the rolling sleeve 54 is tightly pressed against the inspected wheel. After adjustment, the bottom plate 58 and the position of the support shaft 56 in the seat hole 57 are fixed with bolts.

[0038] When testing the anti-lock braking performance of a car, different electromagnetic clutches can be selected to participate in the work according to different car models and different driving modes to form different flywheel combinations. By changing the power-on state of the electromagnetic clutch between the two main rollers 11 of the front and rear testing benches, eight different flywheel combinations can be formed, so that the front and rear axles of the car placed on the main and auxiliary rollers have eight kinds of motion inertia to choose from, which can meet the motion inertia simulation requirements of different car models when testing ABS performance.

[0039] The following is a detailed introduction to the method of using the above-mentioned automobile anti-lock braking system performance test bench to perform ABS performance testing.

[0040] In the initial state, the center distances of the left and right main and auxiliary rollers of the front and rear inspection benches are the same, and can form a suitable placement angle with the wheels of the typical inspected vehicle model. The distance between the center lines of the main and auxiliary rollers of the front inspection bench and the center lines of the main and auxiliary rollers of the rear inspection bench 44 is equal to the front and rear wheelbase of the typical inspected vehicle model.

[0041] Before the conventional braking performance test of the automobile, it is determined whether the wheel placement angle needs to be adjusted according to the wheel size of the vehicle under test. If adjustment is required, the first motor 31 is powered on to drive the plate 32 to move forward and backward, and the second motor 36 drives the second chain 30, the connecting rod 2 and the auxiliary roller 37 to move forward and backward accordingly to adjust the center distance of the left and right main and auxiliary rollers of the front test stand, so that the wheel can obtain a suitable placement angle after being placed on the main and auxiliary rollers. After the position of the auxiliary roller is adjusted in place, the first bearing seat 3 is locked with a locking pin. The piston rod of the lifting cylinder 46 extends to drive the roller locking belt 45 to move up to lock the main roller 11. During detection, all electromagnetic clutches between the left and right main rollers 11 of the front detection stand and the third electromagnetic clutch 61 on the outside of the right front detection unit of the front detection stand are powered off and do not work, the left front detection unit and the right front detection unit work independently, the power of the auxiliary roller 37 of the right front detection unit of the front detection stand is not transmitted to the reduction mechanism 26, and the two first electromagnetic clutches 5 between the reducer 6 of the front detection stand and the main roller 11 are powered on and work, and the power of the force measuring motor 7 can drive the main roller 11 to rotate through the reducer 6. The car is driven onto the inspection platform, and the wheel to be inspected is placed between the main and auxiliary rollers, the transmission is placed in neutral, and the lifting cylinder 46 is started to lower the lifting plate 12. When the wheel presses down the intermediate roller 38 to turn on the travel switch 48, the left and right force measuring motors 7 are started to work, and the main and auxiliary rollers, the wheels placed thereon, and the intermediate roller 38 rotating synchronously with the wheels are driven to rotate at a low speed through the reducer 6, the first electromagnetic clutch 5, and the chain drive. When the vehicle speed is stable, the brake pedal is stepped on. At this time, the wheel is subjected to the brake friction torque and begins to rotate at a reduced speed. The roller driven by the force measuring motor 7 acts on the tangential direction of the wheel periphery to overcome the brake friction torque and maintain the wheel to continue rotating. At the same time, the wheel generates a reaction force on the tangential direction of the roller surface that is equal to and opposite to the braking force. The reaction force causes the reducer 6 housing and the force measuring lever 8 to swing in the opposite direction of the roller rotation. The force at the outer end of the force measuring lever 8 is converted into an electrical signal proportional to the magnitude of the braking force by the force measuring sensor 9. After calibration processing, the braking force of the inspected wheel and its change curve can be obtained. After the braking performance test of one axle wheel is completed, the power supply of the dynamometer motor 7 is cut off, the lifting plate 12 is raised and the main drum 11 is locked, and the remaining axle wheels are then driven onto the testing platform in turn for braking performance testing, and the testing method is the same as the above content.

[0042] Before the anti-lock braking performance test of the vehicle, the third motors 41 on the left and right sides of the rear testing stand 44 are started synchronously according to the wheelbase of the tested vehicle, driving the rear testing stand 44 to move forward and backward as a whole, until the distance between the center lines of the main and auxiliary rollers of the front testing stand and the main and auxiliary rollers of the rear testing stand and the front and rear wheelbase of the tested vehicle are equal, and the rear testing stand 44 is locked and fixed as a whole. According to the different requirements of simulating low adhesion coefficient road surface, high adhesion coefficient road surface, split road surface and butt road surface during the anti-lock braking performance test of the vehicle, the placement angle of each wheel on the corresponding roller is adjusted in real time by the first motor 31 and the second motor 36 to simulate the actual situation when the vehicle brakes on roads with different adhesion coefficients. After the center distances of all the main and auxiliary rollers are adjusted, the lifting cylinder 46 is started, the lifting plate 12 moves up and drives the roller locking belt 45 to lock the main roller 11. The inspected vehicle is driven onto the inspection platform, and the driving wheels of the front-wheel drive vehicle are placed between the left and right main and auxiliary rollers of the front inspection platform, and the non-driving wheels are placed between the left and right main and auxiliary rollers of the rear inspection platform 44, or the driving wheels of the rear-wheel drive vehicle are placed between the left and right main and auxiliary rollers of the rear inspection platform 44, and the non-driving wheels are placed between the left and right main and auxiliary rollers of the front inspection platform. During the inspection, the lifting plate 12 is lowered to place the wheel on the main and auxiliary rollers, and the middle roller 38 is pressed down. The second electromagnetic clutch 60 between the left and right main roller shafts of the front and rear inspection platforms is powered on to make the shafts of the left and right main rollers 11 connected as one. A suitable flywheel combination is selected according to the inertia of the vehicle under inspection, and the electromagnetic clutch carried by the flywheel is powered on, while the two first electromagnetic clutches 5 between the reducer 6 of the front inspection platform and the main roller 11 are powered off, the force measuring motor 7 is not powered on, and the auxiliary roller 3 of the right front inspection unit is powered on. The third electromagnetic clutch 61 on the outer side of 7 is energized to work, so that the output shaft of the auxiliary roller 37 is connected to the input shaft of the speed reduction mechanism 26 as a whole, and the power output when the auxiliary roller 37 rotates is transmitted to the speed reduction mechanism 26 through the third electromagnetic clutch 61, and then driven to rotate the auxiliary roller 37 of the right rear detection unit and the main roller 11 connected to the auxiliary roller 37 through the first chain 22 through the first transmission shaft 28, the second transmission shaft, and the speed increase mechanism 39, and then driven to rotate the main and auxiliary rollers of the left rear detection unit through the left and right main roller shafts of the rear detection stand 44 that have been connected as a whole.Taking the ABS performance test of front-wheel drive vehicles as an example, when the car is in a suitable gear, the driving wheel drives the main roller 11, the auxiliary roller 37, the middle roller 38, and the flywheel installed on the rotating shaft of the main roller 11 of the front detection stand to rotate. At the same time, the auxiliary roller 37 of the right front detection unit of the front detection stand drives the main and auxiliary rollers of the left rear and right rear detection units of the rear detection stand 44 and the driven wheels placed on the main and auxiliary rollers to rotate together through the reduction mechanism 26, the first transmission shaft 28, the second transmission shaft, and the speed increase mechanism 39. When the vehicle speed measured by the vehicle speed sensor 13 reaches the test value set by the national standard, the transmission is placed in neutral and the brake pedal is stepped on. Under the action of the inertia force of the roller and the flywheel, the roller drives the wheel to continue to run. At this time, the real-time values ​​of the vehicle speed and wheel speed are collected through the vehicle speed sensor 13 and the four wheel speed sensors 21, and the wheel slip rate is calculated according to the formula S=(V. 车 -V 轮 ) / V 车 Calculate the slip rate change curves of the four wheels during braking, test the braking time and braking distance at the same time, calculate the braking deceleration, and compare the measured wheel slip rate with the set optimal slip rate to evaluate the anti-lock braking performance of the vehicle.

[0043] Through the above introduction, it is obvious that the test bench can use different combinations of flywheels to simulate the kinetic inertia of different models during braking, and use the adjustable center distance of the main and auxiliary rollers to simulate the anti-lock braking conditions of vehicles with a single low adhesion coefficient, a single high adhesion coefficient, split roads, and butt roads, and can adapt to the braking performance testing needs of vehicles with different wheelbases and different tire diameters. It can not only be used for anti-lock braking performance testing of automobiles, but also compatible with conventional braking performance testing of automobiles. The test bench has strong versatility and high accuracy of test data, which is conducive to objectively reflecting the braking performance of automobiles and ensuring the safety of automobile driving.

Claims

1. A vehicle anti-lock braking system performance test bench, characterized in that: The invention comprises four detection units corresponding to the wheels one by one, the detection units comprising a main roller (11), a secondary roller (37) and a main and secondary roller center distance adjustment mechanism; the rotating shaft of the main roller (11) is mounted on two second bearing seats (10), the rotating shaft of the secondary roller (37) is mounted on two first bearing seats (3), the second bearing seats (10) are fixedly arranged, and the first bearing seats (3) are slidably arranged on a first guide rail (1) below the second bearing seats; the rotating shafts of the main and secondary rollers are dynamically connected via a sprocket chain with a tensioning mechanism; the first and second bearing seats are connected via a return spring (4), and the secondary roller (37) can be adjusted in front and rear positions under the action of the main and secondary roller center distance adjustment mechanism and the return spring (4); The number of the main and auxiliary roller center distance adjustment mechanisms is two sets, the left front and right front detection units share one set, and the left rear and right rear detection units share one set; the two first bearing seats (3) are connected by a connecting rod (2); the main and auxiliary roller center distance adjustment mechanism comprises a plate (32) that can move forward and backward, and a third sprocket (35) is provided on the plate (32), and the third sprocket (35) is located on the left-right symmetrical center plane of the detection platform; the second chain (30) meshed with the third sprocket (35) has two ends that pass around the fixed second sprocket (29) and are respectively connected to the two connecting rods (2); The third sprocket (35) is mounted on the output shaft of the second motor (36), and the second motor (36) is arranged on the plate (32); When the plate (32) moves forward and backward, the second chain (30) pulls the connecting rod (2) backward, thereby increasing the center distance between the primary and secondary rollers of the two detection units at the same amplitude, or, under the joint action of the return spring (4) and the tensioning mechanism, reducing the center distance between the primary and secondary rollers of the two detection units at the same amplitude, thereby achieving the simulated running of the two coaxial wheels on a road surface with the same adhesion coefficient; When the second motor (36) rotates, the second chain (30) pulls the connecting rod (2) on one side connected thereto, thereby increasing the center distance between the primary and secondary rollers on that side; the second chain (30) on the other side is relaxed, and under the joint action of the return spring (4) and the tensioning mechanism on the other side, the center distance between the primary and secondary rollers on the other side is reduced, thereby achieving reverse adjustment of the center distance between the primary and secondary rollers of the two detection units, so that the two coaxial wheels can simulate running on roads with different adhesion coefficients.

2. The vehicle anti-lock braking system performance test bench according to claim 1 is characterized in that: A flywheel mechanism with adjustable motion inertia is arranged on the rotating shaft of the main drum (11).

3. The vehicle anti-lock braking system performance test bench according to claim 2 is characterized in that: The flywheel mechanism comprises a large flywheel (15), a middle flywheel (19) and a small flywheel (20) which are arranged in sequence from the main roller (11) to the central plane direction of the detection platform in a left-right symmetrical manner, wherein the large flywheel (15) and the middle flywheel (19) are provided with an electromagnetic clutch; in two detection units on the same side at the front and rear, the rotating shafts of the two main rollers (11) are connected via a second electromagnetic clutch (60).

4. The vehicle anti-lock braking system performance test bench according to claim 1 is characterized in that: It also comprises a fixed front detection stand and a rear detection stand (44) that can move forward and backward, the left front and right front detection units being arranged on the front detection stand, and the left rear and right rear detection units being arranged on the rear detection stand (44); the auxiliary roller (37) of the right front detection unit has a rotating shaft connected to a speed reduction mechanism (26) via a third electromagnetic clutch (61), and the speed reduction mechanism (26) is connected to a first transmission shaft (28) via a coupling (27); the auxiliary roller (37) of the right rear detection unit has a rotating shaft connected to a speed increase mechanism (39), and the speed increase mechanism (39) is connected to a second transmission shaft via a coupling (27); the first transmission shaft (28) is provided with an external spline, the second transmission shaft has an internal spline, and the first transmission shaft (28) is plug-connected to the second transmission shaft.

5. The vehicle anti-lock braking system performance test bench according to claim 1 is characterized in that: The detection unit further comprises a wheel protection mechanism, the wheel protection mechanism comprising a vertical plate (55), the vertical plate (55) being movable leftward and rightward on the cover plates at the outer ends of the main and auxiliary rollers; the vertical plate (55) is provided with seat holes (57) at the front, rear and upper ends, a bent support shaft (56) being inserted into the seat hole (57), a rolling sleeve (54) being provided on the support shaft (56) for pressing against the wheel; the seat hole (57) is a long hole, and the position of the support shaft (56) in the seat hole (57) is adjustable.

6. The vehicle anti-lock braking system performance test bench according to claim 1 is characterized in that: A wheel-in-place and roller locking mechanism is provided between the main and auxiliary rollers, the wheel-in-place and roller locking mechanism comprising an intermediate roller (38) and a lifting plate (12), the two ends of the intermediate roller (38) being supported by supporting arms (50); a spring (47) and a travel switch (48) are installed below the supporting arms (50); a lifting cylinder (46) is installed between the main and auxiliary rollers near the main roller (11) to drive the lifting plate (12) to move up and down; a roller locking belt (45) is installed between the lifting plate (12) and the mounting frame of the main roller (11), the roller locking belt (45) passing over the bottom of the main roller (11).

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