JJG 908-2023Automobile Side Slip Testers (English PDF)

5.1 Side slip distance

5.1.1 Measuring range

The measuring range of side slip distance shall not be less than 10.0 m/km both inward and outward.

5.1.2 Resolution

The resolution of the display device of the side slip tester shall not be greater than 0.1 m/km.

5.1.3 Zero error

The zero error of side slip distance shall not exceed ±0.2 m/km.

5.1.4 Instrument drift

Instrument drift shall not exceed ±0.2 m/km.

5.1.5 Indication error

5.1.5.1 Static indication error: The static indication error of side slip distance shall not exceed ±0.2 m/km.

5.1.5.2 Dynamic indication error: The dynamic indication error of side slip distance

shall not exceed ±0.2 m/km.

5.1.6 Repeatability

Repeatability shall not be greater than 0.1 m/km.

5.2 Height difference of side slipper

The height difference between the points on the left and right slippers of the side slip tester shall not exceed 5 mm.

5.3 Displacement synchronization of side slipper

For twin slipper side slip testers, the displacement synchronization of the left and right slippers shall not exceed 0.1 mm.

5.4 Force required for the slipper to move

5.4.1 The force required for the slipper to move from the zero position to 0.1 mm shall not exceed 60 N.

5.4.2 The force required for the slipper to move from the zero position to 5 mm shall not exceed 120 N.

6.1 Appearance and general requirements

6.1.1 On the side slipper, there shall be a clear nameplate, which shall indicate the equipment name, specification and model, rated load, measuring range, manufacturer’s name, production date, factory number, etc.

6.1.2 The slipper shall move flexibly and smoothly without any obvious blockage.

There shall be no obvious movement of the slipper along the direction of vehicle travel.

6.1.3 The instrument display shall be clear and stable, without defects affecting the readings.

the instrument and displacement measuring device (or dial gauge). Use the displacement control device of the verification device (or use a micro-motion tool) to slowly push the slipper to move the slipper. When value indicated by the displacement measuring device (or dial gauge) reaches the verification point, record the indicated value of the side slip tester. Repeat this method 3 times inwardly and outwardly, and calculate the indication error of each verification point according to Formula (1). The indication error shall meet the requirements of

5.1.5.1.

Where:

deltai – indication error of the ith verification point (i = 1,2,3), m/km;

– the average value of the 3 indications of the side slip instrument at the ith verification point (i=1,2,3), m/km;

XSL – the equivalent side slip distance of the ith verification point displacement measuring device (or dial gauge), which is calculated from the vertical effective measurement length of the slipper, m/km, calculated according to Formula (2).

Where:

XSL – the equivalent side slip distance of the ith verification point displacement measuring device (or dial gauge), which is calculated from the vertical effective measurement length of the slipper, m/km;

XS – displacement measuring device (or dial gauge) display value of the ith verification point (i=1,2,3), mm;

L – vertical effective measurement length of the slipper (measured value), m.

(2) Dynamic indication error

Install the control device, displacement measuring device and gear tool of the verification device as shown by Figure 1. The axis of the measuring rod of the displacement measuring device shall be consistent with the moving direction of the slipper. Adjust the side slip tester to the detection state, and adjust the zero position of the side slip testing instrument and displacement measuring device. Set the advance rate of the control device to be about 7 mm/s, and the advance displacement to 5 mm. Start the displacement control device of the verification

Where:

R – repeatability, m/km;

Xi max – the maximum value indicated by the side slip tester at the ith verification point (i=1,2,3), m/km;

Xi min – the minimum value indicated by the side slip tester at the ith verification point (i=1,2,3), m/km;

C – range coefficient, C = 1.69.

7.3.2.2 Height difference of side slipper

Place the laser line projecting (marking) instrument at an appropriate position on the nearby ground; adjust its level to emit a horizontal beam. Select 5 measuring points on the left and right slippers (usually at the four corners about 20 cm from the edge of the side slipper and the center of the side slipper); place the steel ruler on the measurement points perpendicular to the side slipper. Use a laser line projecting (marking) instrument and a steel ruler to measure the height of each point relative to the same reference level.

The difference between the maximum value and the minimum value of the height is the height difference of the side slipper. Calculate the height difference of the side slipper according to Formula (6), which shall meet the requirements of 5.2.

Where:

deltaH – height difference of side slipper, mm;

Hmax – the maximum value of each measuring point on the left and right slides of the side slipper, mm;

Hmin – the minimum value of each measuring point on the left and right slides of the side slipper, mm.

7.3.2.3 Displacement synchronization of side slipper

According to the method in Figure 1 (or Figure 2), install displacement measuring devices (or dial gauges) and gear tools on both the left and right slides, so that the axes of the measuring rods of the displacement measuring devices (or dial gauges) are consistent with the moving direction of the slippers. Adjust the side slip tester to the calibration state, and adjust the zero position of the side slip testing instrument and the left and right displacement measuring devices (or dial gauges). Use the control device of the verification device (or use a micro-motion tool) to push the left and right slippers inwards and outwards; when the side slip testing instrument shows that the side slip is about 5.0 m/km, read the left and right displacement measuring devices (or dial gauges).

......