A hydraulic retarder testing fixture, testing system and testing method

Abstract

This invention provides a hydraulic retarder testing fixture, testing system, and testing method to address the technical problems of existing testing methods being overly cumbersome, and suffering from high production costs and low production efficiency during the testing process. The testing fixture of this invention, consisting of a front housing, rear housing, flange, and gasket, has a simple overall structure, is easy to assemble and disassemble, and enables rapid testing of the hydraulic retarder's performance. It also avoids the repeated disassembly and reassembly of the automatic transmission during testing, solving the problems of material consumption and time consumption caused by repeated disassembly and reassembly of the hydraulic retarder, improving the first-pass yield of the hydraulic retarder, thereby increasing production efficiency and reducing production costs.

Description

Technical Field

[0001] This invention relates to a method for testing mechanical equipment, specifically to a testing fixture, testing system, and testing method for a hydraulic retarder. Background Technology

[0002] The vehicle braking system is one of the most crucial systems for safe vehicle operation. With advancements in engine technology and improvements in road conditions, vehicle speeds and intervals between trips have significantly increased, leading to a substantial rise in kinetic energy. Traditional friction-pad braking systems can no longer meet the demands of prolonged, high-intensity vehicle operation. Frequent or prolonged use of the service brakes can cause brake fade due to overheating of the friction pads, potentially resulting in brake failure and threatening driving safety. Furthermore, frequent replacement of brake pads and tires increases transportation costs. Hydraulic retarders, as safe and reliable auxiliary braking devices, offer advantages such as high high-speed braking torque, smooth braking, low noise, long lifespan, and compact size, and are widely used in heavy vehicles and construction machinery.

[0003] Currently, most heavy-duty vehicles are equipped with integrated hydraulic retarders, which are hydraulic retarders integrated into the automatic transmission. This simplifies the design of the hydraulic system and the cooling system, making the overall transmission system structure more compact and reducing the overall weight of the vehicle.

[0004] Furthermore, the performance of the hydraulic retarder also affects the vehicle's braking ability and the overall vehicle cooling system. Several parameters, including the blade parameters and flow channel quality of the driving and stationary impellers, the matching and assembly clearance control of the driving and stationary impellers, and the driving impeller's operational runout, are crucial to the retarder's performance and reliability. These parameters also influence each other. Current methods for testing hydraulic retarders involve repeated assembly, disassembly, and adjustment during actual production and testing. This process is cumbersome, and repeated disassembly and reassembly of the automatic transmission leads to the scrapping of easily damaged and consumable internal parts. It also wastes consumables such as cleaning fluid and lubricating grease, increasing production costs and reducing production efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a hydraulic retarder testing fixture, system, and method to address the technical problems of existing testing methods being overly cumbersome, and suffering from high production costs and low efficiency during the testing process. The method of this invention can quickly and easily measure the graded output braking torque and fluctuation of the hydraulic retarder, improving the adjustment and verification efficiency of the hydraulic retarder, optimizing its performance, enhancing its reliability, and solving the problems of material consumption and time-consuming processes caused by repeated disassembly and reassembly of the hydraulic retarder in automatic transmissions. This also improves production efficiency and reduces production costs.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A hydraulic retarder testing fixture, characterized in that it includes a front housing, a rear housing, and a flange.

[0008] The front housing and the rear housing are coaxially sleeved on the main shaft of the hydraulic retarder and are respectively connected to the main shaft through bearings; a cavity is formed between the front housing and the rear housing, and the stationary wheel and the moving wheel of the hydraulic retarder are installed in the cavity;

[0009] The rear housing is provided with an oil inlet, an oil outlet, a heat dissipation inlet, and a heat dissipation outlet parallel to the axial direction, which correspond to the oil inlet, oil outlet, heat dissipation inlet, and heat dissipation outlet of the hydraulic retarder, respectively.

[0010] The flange is located at the front end of the front housing, with one end connected to the input device and the other end connected to the spindle.

[0011] Furthermore, the testing fixture also includes strain gauges, which are uniformly disposed on the front surface of the front housing.

[0012] Furthermore, it also includes a shim. The front housing is connected to the main shaft via a tapered roller bearing. The spline sleeve at the shaft end of the hydraulic retarder is fitted onto the main shaft and is located between the tapered roller bearing and the driven wheel. The shim is located between the end of the main shaft and the flange and is used to adjust the axial clearance of the tapered roller bearing, thereby adjusting the installation clearance between the driven wheel and the stationary wheel.

[0013] Based on this testing fixture, the present invention also provides a hydraulic retarder testing system, which is characterized in that: it includes the above-mentioned testing fixture, and also includes a control unit, a heat dissipation unit and a testing unit;

[0014] The testing fixture is used to assemble the hydraulic retarder with the stationary wheel, moving wheel, main shaft and shaft end spline sleeve of the hydraulic retarder to form the hydraulic retarder to be tested.

[0015] The control unit includes a main controller, a proportional solenoid valve, and a retarder control valve.

[0016] One end of the proportional solenoid valve is connected to the main controller, and the other end is connected to the retarder control valve. The retarder control valve is installed on the rear housing and connected to the hydraulic retarder under test. The main controller operates the opening and closing of the retarder control valve and the staged braking through the proportional solenoid valve, thereby controlling the filling amount of the hydraulic retarder under test.

[0017] The heat dissipation unit includes a radiator and an oil tank. The radiator is connected to the heat dissipation inlet and outlet of the hydraulic retarder under test through the heat dissipation inlet and outlet of the testing fixture, respectively, for cooling the oil inside the hydraulic retarder under test. The oil tank is connected to the oil inlet and outlet of the hydraulic retarder under test through the oil inlet and outlet of the testing fixture, respectively, for supplying oil to the hydraulic retarder under test and recycling the oil flowing through the hydraulic retarder under test.

[0018] The testing unit includes a testing platform for placing the hydraulic retarder under test and testing equipment placed on the testing platform. The testing equipment is used to test the performance of the hydraulic retarder under test.

[0019] Furthermore, the present invention also provides a method for detecting a hydraulic retarder, which employs the above-mentioned hydraulic retarder detection system and includes the following steps:

[0020] Step 1: Install the stationary wheel, moving wheel, main shaft and shaft end spline sleeve of the hydraulic retarder onto the testing fixture to form the hydraulic retarder to be tested, and fix the hydraulic retarder to be tested on the testing table.

[0021] Step 2: Connect the hydraulic retarder to be tested to the retarder control valve, test equipment, radiator, oil tank and pipeline respectively;

[0022] Step 3: The main controller operates the retarder control valve and the graded braking at different gears via the proportional solenoid valve. The braking torque of the hydraulic retarder under test is measured at different gears using testing equipment. It is determined whether the minimum braking torque of the hydraulic retarder under test is greater than or equal to 1000 Nm when the engine speed is 1000 r / min, and the heat dissipation power of the hydraulic retarder under test at the maximum braking torque is less than or equal to three-quarters of the engine power when the engine speed is 2000 r / min. If the conditions are met, proceed to step 5; otherwise, proceed to step 4.

[0023] Step 4: Disassemble and adjust the installation gap between the stationary wheel and the moving wheel so that the installation gap between them is 1.5 to 1.9 mm, and return to S1;

[0024] Step 5: Measure the braking torque fluctuation of the hydraulic retarder under test and the strain amplitude change of the strain gauge on the testing fixture using the testing equipment. Determine whether the braking torque fluctuation is ≤100Nm and the strain amplitude change is ≤5 times the normal amplitude. If the conditions are met, the performance test of the hydraulic retarder under test is completed; otherwise, proceed to step 6.

[0025] Step 6: Disassemble and inspect the interference marks between the moving wheel and the front housing, and between the moving wheel and the stationary wheel. Based on the depth of the interference marks, adjust the blade depth of the moving wheel or stationary wheel to eliminate the interference. The difference between the maximum and minimum values ​​of the blade depth A is ≤ 1.2mm. Then return to S1.

[0026] Further, step 1 specifically involves installing the stationary wheel of the hydraulic retarder onto the front housing, and measuring the axial distance L1 from the rear end face of the front housing to the rear end of the tapered roller bearing, the axial distance L2 from the rear end face of the stationary wheel to the rear end face of the front housing, and the axial distance L3 from the end face of the moving wheel near the tapered roller bearing to the end face of the blade. The thickness T of the shaft end spline sleeve is calculated using the fitting clearance S between the moving wheel and the stationary wheel. The appropriate shaft end spline sleeve is then installed between the moving wheel and the tapered roller bearing. Next, the rear housing is installed to form the hydraulic retarder to be tested, and the hydraulic retarder to be tested is fixed on the testing table.

[0027] Furthermore, in step 1, the formula for calculating the thickness of the shaft end spline sleeve is: T = L1 + S - L2 - L3.

[0028] Furthermore, in step 1, the proposed fit gap S is taken as 1.2 to 2.1 mm.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1. The front housing, rear housing, flange, and main shaft of the testing fixture of the present invention have a simple overall structure and are easy to assemble and disassemble. They can realize rapid testing of the performance of hydraulic retarders, and at the same time avoid repeated disassembly and assembly of automatic transmissions during the testing process. This solves the problem of material consumption and time consumption caused by repeated disassembly and assembly of hydraulic retarders to automatic transmissions, improves the first pass rate of hydraulic retarders, and thus improves production efficiency and reduces production costs.

[0031] 2. The testing fixture of the present invention can guide the adjustment of multiple key characteristic parameters of the moving and stationary impellers of the hydraulic retarder, optimize the impeller structure parameters of the moving and stationary impellers, thereby optimizing the assembly parameters of the hydraulic retarder, improving the braking stability of the hydraulic retarder, and obtaining the optimal performance of the hydraulic retarder.

[0032] 3. The detection system of the present invention can achieve multi-level pressure output by controlling the proportional solenoid valve, and adjust the filling volume of the hydraulic circulation chamber in stages. Furthermore, strain gauges are uniformly attached to the surface of the front housing, which can detect the influence of the staged braking torque output on the wheel yaw, thereby improving the reliability of the hydraulic retarder.

[0033] 4. The testing method of the present invention can quickly and easily measure the braking torque and fluctuation of the hydraulic retarder, determine whether the performance of the hydraulic retarder matches the vehicle system, and at the same time, it does not require repeated disassembly and assembly of the automatic transmission during parameter adjustment, thereby improving the testing efficiency and the product qualification rate. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of an embodiment of a hydraulic retarder performance testing fixture according to the present invention;

[0035] Figure 2 for Figure 1 Enlarged view of the middle section (I);

[0036] Figure 3 for Figure 1 Enlarged view of Part II;

[0037] Figure 4 for Figure 1 Enlarged view of Part III;

[0038] Figure 5 for Figure 1 The right view;

[0039] Figure 6 This is a schematic diagram illustrating the working principle of an embodiment of a hydraulic retarder performance testing system according to the present invention.

[0040] Figure label:

[0041] 1-Front housing, 2-Rear housing, 21-Oil inlet, 22-Oil outlet, 23-Heat dissipation inlet, 24-Heat dissipation outlet, 3-Flange, 4-Main shaft, 5-Stationary wheel, 6-Driving wheel, 7-Shaft end spline sleeve, 8-Gasket, 9-Main controller, 10-Proportional solenoid valve, 11-Retarder control valve, 12-Radiator, 13-Oil tank, 14-Hydraulic retarder under test. Detailed Implementation

[0042] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the term "front" used in the present invention refers to the end closer to the power input, that is, the side where the flange is located, and "rear" refers to the end closer to the power output, that is, the other side away from the flange.

[0043] like Figures 1 to 5 As shown, the present invention provides a hydraulic retarder testing fixture, including a front housing 1, a rear housing 2, a flange 3, strain gauges and gaskets 8.

[0044] The front housing 1 and the rear housing 2 are coaxially mounted on the main shaft 4 of the hydraulic retarder and are connected to the main shaft 4 via bearings. A tapered roller bearing is also provided between the front housing 1 and the main shaft 4. The shaft end spline sleeve 7 of the hydraulic retarder is mounted on the main shaft 4 and is located between the tapered roller bearing and the driving wheel 6. The shaft end spline sleeve 7 is connected to the driving wheel 6 via a spring pin or a cylindrical pin. A cavity is formed between the front housing 1 and the rear housing 2, which is used to install the stationary wheel 5 and the driving wheel 6 of the hydraulic retarder. After installation, the rear housing 2 is fixedly connected to the front housing 1 with bolts. The rear housing 2 has an oil inlet 21, an oil outlet 22, a heat dissipation inlet 23, and a heat dissipation outlet 24 parallel to the axial direction, corresponding to the oil inlet, oil outlet, heat dissipation inlet, and heat dissipation outlet of the hydraulic retarder, respectively. The flange 3 is located at the front end of the front housing 1. One end of the flange 3 is connected to the input device, and the other end is splined to the main shaft 4. The shim 8 is located between the end of the main shaft 4 and the flange 3, and is used to adjust the axial clearance of the tapered roller bearing, thereby improving the bearing's service life. Strain gauges are evenly distributed on the front surface of the front housing 1. During testing, the change in strain amplitude of the strain gauges reflects the interference between the moving wheel 6 and the front housing 1, and between the moving wheel 6 and the stationary wheel 5. This allows for the detection of the wheel's runout under different performance conditions of the hydraulic retarder, thereby optimizing the overall performance of the hydraulic retarder.

[0045] The main shaft 4 is a splined shaft. After installation, the flange 3 transmits power from the power input device to the main shaft 4, which drives the drive wheel 6 to rotate via the spline. The working fluid enters the cavity through the inlet 21. During the flow of the fluid, a pressure difference is created within the hydraulic retarder, thereby achieving vehicle braking. Specifically, the working fluid enters the cavity through the inlet 21, and the drive wheel 6 drives the fluid to rotate around its axis. Simultaneously, the fluid moves along the blades of the drive wheel 6 and is thrown towards the stationary wheel 5. The blades of the stationary wheel 5 exert a reaction force on the fluid, causing it to flow out of the stationary wheel 5 and then rotate back to impact the drive wheel 6, thus creating a resistance torque on the drive wheel 6, hindering its rotation, and achieving vehicle deceleration. During its movement, the working fluid creates a pressure difference between the inlet and outlet, and the fluid circulates. When passing through the radiator, the heat is carried away by the cooling water of the cooling system.

[0046] like Figure 6 As shown, based on the present invention, a hydraulic retarder testing fixture is provided. The present invention also provides a hydraulic retarder testing system, including a control unit, a heat dissipation unit, a testing unit, and the testing fixture of the present invention. The testing fixture is used to assemble the hydraulic retarder with the main shaft 4, stationary wheel 5, moving wheel 6, and shaft end spline sleeve 7 to form the hydraulic retarder to be tested.

[0047] The control unit includes a main controller 9, a proportional solenoid valve 10, and a retarder control valve 11. One end of the proportional solenoid valve 10 is connected to the main controller 9, and the other end is connected to the retarder control valve 11. The retarder control valve 11 is mounted on the rear housing 2 and connected to the hydraulic retarder under test. The main controller 9 is connected to the proportional solenoid valve 10 via a wiring harness. The air inlet of the proportional solenoid valve 10 is connected to the air source of the test bench via an air pipe, and the air outlet of the proportional solenoid valve 10 is connected to the piston of the retarder control valve 11 via an air pipe. The retarder has tiered braking with 1 to 6 levels. The tester operates the main controller 9 to different levels, and the proportional solenoid valve 10 outputs different pressures of air to the retarder control valve 11, thereby pushing the valve core of the retarder control valve 11 to different positions. This controls the oil inlet opening and filling volume of the hydraulic retarder under test, thus enabling the testing of the performance of the hydraulic retarder under test at different levels.

[0048] The heat dissipation unit includes a radiator 12 and an oil tank 13. The radiator 12 is connected to the heat dissipation inlet 23 and heat dissipation outlet 24 of the testing fixture, respectively, for cooling the oil in the hydraulic retarder under test. The oil tank 13 is connected to the oil inlet 21 and oil outlet 22 of the testing fixture, respectively, for supplying oil to the hydraulic retarder under test and for recycling the oil flowing through the hydraulic retarder under test.

[0049] The testing unit includes a testing platform for placing the hydraulic retarder under test and testing equipment placed on the testing platform. The testing equipment is used to test the performance of the hydraulic retarder under test.

[0050] Furthermore, based on the testing fixture and testing system of the present invention, the present invention also provides a method for testing a hydraulic retarder, comprising the following steps:

[0051] Step 1: Install the main shaft 4, stationary wheel 5, moving wheel 6 and shaft end spline sleeve 7 of the hydraulic retarder onto the testing fixture to form the hydraulic retarder 14 to be tested, and fix the hydraulic retarder 14 to be tested on the testing table.

[0052] Specifically, strain gauges are attached to the front surface of the front housing 1. The stationary wheel 5 of the hydraulic retarder is installed onto the front housing 1. The axial distances L1 from the rear end face of the front housing 1 to the rear end of the tapered roller bearing, L2 from the rear end face of the stationary wheel 5 to the rear end face of the front housing 1, and L3 from the end face of the moving wheel 6 near the tapered roller bearing to the blade end face are measured. The thickness T of the shaft end spline sleeve 7 is calculated using the intended fit clearance S between the moving wheel 6 and the stationary wheel 5. The appropriate shaft end spline sleeve 7 is then installed between the moving wheel and the tapered roller bearing. Next, the rear housing 2 and the control valve are installed to form the hydraulic retarder 14 under test, which is then fixed on the testing table. The formula for calculating the thickness of the shaft end spline sleeve 7 is: T = L1 + S - L2 - L3, where the intended fit clearance S is generally between 1.2 and 2.1 mm, within which the overall performance of the two components is optimal.

[0053] To improve assembly stability, during the assembly process, the height H between the left end face of the spindle 4 and the left end face of the inner spline of the flange 3 can be measured, and a shim 8 can be placed at this point. The thickness of the shim 8 is t = H + (0.02 ~ 0.05). By adding the shim 8, the axial clearance of the tapered roller bearing at the front housing 1 can be guaranteed, thereby improving the service life of the bearing.

[0054] Step 2: Connect the hydraulic retarder 14 to the test equipment, radiator 12, oil tank 13 and pipeline respectively to provide the hydraulic retarder 14 with working status.

[0055] Step 3: The main controller 9 controls the opening and closing of the retarder control valve 11 and the graded braking at different gears via the proportional solenoid valve 10. The tester controls the main controller 9 to different gears, and the proportional solenoid valve 10 can output air pressure of different pressures to the retarder control valve 11, pushing the valve core of the retarder control valve 11 to different positions, thereby controlling the oil inlet opening and filling volume of the hydraulic retarder 14 under test. The braking torque of the hydraulic retarder 14 under test at different gears is measured by the testing equipment, and the hydraulic retarder bench test data guides the adjustment of the assembly clearance of the moving wheel 6 and the stationary wheel 5, the matching of the moving wheel 6 and the stationary wheel 5, and the rework of parts. Determine whether the minimum braking torque value of the hydraulic retarder 14 under test is ≥1000Nm when the engine speed is 1000r / min, and at the same time, the heat generation power of the hydraulic retarder 14 under test at the maximum braking torque is less than or equal to three-quarters of the engine power when the engine speed is 2000r / min. If the requirements are met, proceed to step 5; otherwise, proceed to step 4.

[0056] Step 4: Disassemble and adjust the installation gap between the stationary wheel 5 and the moving wheel 6 so that the installation gap between them is 1.5 to 1.9 mm, and then return to step 1.

[0057] Specifically, when the braking torque is too small, it can be adjusted by increasing the assembly clearance between the moving wheel 6 and the stationary wheel 5, or by appropriately increasing the blade depth of the moving wheel 6 or the stationary wheel 5.

[0058] When the braking torque is too large, it can be adjusted by reducing the assembly clearance between the moving wheel 6 and the stationary wheel 5, or by appropriately reducing the blade depth of the moving wheel 6 or the stationary wheel 5.

[0059] When adjusting the assembly clearance, the installation clearance between the stationary wheel 5 and the moving wheel 6 can be adjusted by adjusting the thickness of the shaft end spline sleeve 7; or by adjusting the thickness of the shim 8; or by a combination of adjusting the thickness of the shaft end spline sleeve 7 and the shim 8. In this embodiment, the assembly clearance is mainly adjusted by adjusting the thickness of the shaft end spline sleeve 7.

[0060] Step 5: Measure the braking torque fluctuation of the hydraulic retarder 14 under different gears and the strain amplitude change of the strain gauge on the testing fixture using the testing equipment. Determine whether the braking torque fluctuation is ≤100Nm and the strain amplitude change is ≤5 times the normal amplitude. If it is satisfied, the hydraulic retarder performance test is completed; otherwise, proceed to step 6.

[0061] Step 6: Disassemble and inspect the interference marks between the moving wheel 6 and the front housing 1, and between the moving wheel 6 and the stationary wheel 5. Based on the depth of the interference marks, adjust the blade depth of the moving wheel 6 or the stationary wheel 5 to eliminate the interference. The difference between the maximum and minimum values ​​of the blade depth A is ≤ 1.2 mm. Then return to S1.

[0062] Specifically, after the retarder has stabilized, if the braking torque fluctuation or strain amplitude change is too large, the interference marks between the moving wheel 6 and the front housing 1, and between the moving wheel 6 and the stationary wheel 5, are inspected. Based on the depth of the interference marks, the blade depth of the moving wheel 6 or stationary wheel 5 is adjusted to control the consistency and uniformity of the blade depth distribution. The difference between the maximum and minimum blade depth of the moving wheel 6 or stationary wheel 5 should generally not exceed 1.2 mm, and a maximum difference of 1.5 mm between the depths of three blades is allowed, but the three blades cannot be adjacent and must be evenly distributed on the stationary wheel 5 or moving wheel 6. After adjustment, once the retarder has stabilized, the maximum braking torque fluctuation should generally not exceed 100 Nm, and the strain amplitude change of the strain gauges should generally not exceed five times the normal amplitude.

[0063] The detection method of this invention can comprehensively optimize multiple key parameters such as the driving wheel, stationary wheel, and assembly, thereby optimizing the performance of the retarder. While ensuring smooth braking of the hydraulic retarder and minimizing the sway of the driving wheel to avoid interference risks, it can also achieve a large braking torque at high speeds to meet the needs of vehicle use.

Claims

1. A method for testing a hydraulic retarder, employing a hydraulic retarder testing system, the testing system comprising a testing fixture, a control unit, a heat dissipation unit, and a testing unit; the testing fixture comprising a front housing (1), a rear housing (2), a flange (3), strain gauges, and gaskets (8); the front housing (1) and the rear housing (2) are coaxially mounted on the main shaft (4) of the hydraulic retarder, and are respectively connected to the main shaft (4) via bearings; a cavity is formed between the front housing (1) and the rear housing (2), the cavity being used to install the stationary wheel (5) and the moving wheel (6) of the hydraulic retarder; the rear housing (2) is provided with an oil inlet (21), an oil outlet (22), and a heat dissipation inlet parallel to the axial direction. (23) and heat dissipation outlet (24) correspond to the oil inlet, oil outlet, heat dissipation inlet and heat dissipation outlet of the hydraulic retarder, respectively; the flange (3) is located at the front end of the front housing (1), one end of the flange (3) is connected to the input device and the other end is connected to the main shaft (4); the strain gauges are evenly arranged on the front surface of the front housing (1); the front housing (1) and the main shaft (4) are connected by a tapered roller bearing, the shaft end spline sleeve (7) of the hydraulic retarder is sleeved on the main shaft (4) and located between the tapered roller bearing and the drive wheel (6); the gasket (8) is located between the end of the main shaft (4) and the flange (3) and is used to adjust the axial clearance of the tapered roller bearing; The control unit includes a main controller (9), a proportional solenoid valve (10), and a retarder control valve (11); One end of the proportional solenoid valve (10) is connected to the main controller (9), and the other end is connected to the retarder control valve (11). The retarder control valve (11) is installed on the rear housing (2) of the testing fixture and connected to the hydraulic retarder to be tested. The main controller (9) controls the opening and closing of the retarder control valve (11) and the graded braking through the proportional solenoid valve (10), thereby controlling the filling amount of the hydraulic retarder to be tested. The heat dissipation unit includes a radiator (12) and an oil tank (13). The radiator (12) is connected to the heat dissipation inlet (23) and heat dissipation outlet (24) of the testing fixture, respectively, for cooling the oil in the hydraulic retarder under test. The oil tank (13) is connected to the oil inlet (21) and oil outlet (22) of the testing fixture, respectively, for supplying oil to the hydraulic retarder under test and recycling the oil flowing through the hydraulic retarder under test. The testing unit includes a testing platform for placing the hydraulic retarder to be tested and a testing device placed on the testing platform. The testing device is used to test the performance of the hydraulic retarder to be tested. Its features are, Includes the following steps: Step 1: Install the main shaft (4), stationary wheel (5), moving wheel (6) and shaft end spline sleeve (7) of the hydraulic retarder onto the testing fixture to form the hydraulic retarder (14) to be tested, and fix the hydraulic retarder (14) to be tested on the testing table. Step 2: Connect the hydraulic retarder (14) to be tested to the retarder control valve (11), the test equipment, the radiator (12), the oil tank (13) and the pipeline respectively; Step 3: The main controller (9) controls the opening and closing of the retarder control valve (11) and the graded braking at different gears through the proportional solenoid valve (10). The braking torque of the hydraulic retarder (14) under test at different gears is measured by the testing equipment. It is determined whether the minimum braking torque of the hydraulic retarder (14) under test is greater than or equal to 1000 Nm when the engine speed is 1000 r / min, and the heat generation power of the hydraulic retarder (14) under test at the maximum braking torque is less than or equal to three-quarters of the engine power when the engine speed is 2000 r / min. If the conditions are met, step 5 is executed; otherwise, step 4 is executed. Step 4: Disassemble and adjust the installation gap between the stationary wheel (5) and the moving wheel (6) so that the installation gap between them is 1.5 to 1.9 mm, and return to S1; Step 5: Measure the braking torque fluctuation of the hydraulic retarder (14) under test and the strain amplitude change of the strain gauge on the testing fixture using the testing equipment. Determine whether the braking torque fluctuation is ≤100Nm and the strain amplitude change is ≤5 times the normal amplitude. If it is satisfied, the performance test of the hydraulic retarder (14) under test is completed. Otherwise, proceed to step 6; Step 6: Disassemble and inspect the interference marks between the moving wheel (6) and the front housing (1), and between the moving wheel (6) and the stationary wheel (5). Based on the depth of the interference marks, adjust the blade depth of the moving wheel (6) or the stationary wheel (5) to eliminate the interference. The difference between the maximum and minimum values ​​of the blade depth A is ≤ 1.2 mm. Then return to S1.

2. The method for detecting a hydraulic retarder according to claim 1, characterized in that: Step 1 is as follows: Install the stationary wheel (5) of the hydraulic retarder onto the front housing (1), and measure the axial distance L1 from the rear end face of the front housing (1) to the rear end of the tapered roller bearing, the axial distance L2 from the rear end face of the stationary wheel (5) to the rear end face of the front housing (1), and the axial distance L3 from the end face of the moving wheel (6) near the tapered roller bearing to the blade end face. Calculate the thickness T of the shaft end spline sleeve (7) by using the fitting clearance S between the moving wheel (6) and the stationary wheel (5), and install the matching shaft end spline sleeve (7) between the moving wheel (6) and the tapered roller bearing. Then install the rear housing (2) to form the hydraulic retarder (14) to be tested, and fix the hydraulic retarder (14) to be tested on the testing table.

3. The method for detecting a hydraulic retarder according to claim 2, characterized in that: In step 1, the thickness calculation formula for the shaft end spline sleeve (7) is: T=L1+S-L2-L3.

4. The method for detecting a hydraulic retarder according to claim 3, characterized in that: In step 1, the proposed fit clearance S is 1.2 to 2.1 mm.

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