HYDRAULIC HOSES

Nowadays almost all road-building, municipal and other Russian and foreign vehicles have hydraulic transmission.

Hydraulic transmission break down rarely, but from time to time it is necessary to change the old details, including hydraulic hoses.

We would like to tell about the possibility to replace the foreign hoses to Russian ones. Nowadays Russian specialists use foreign hydraulic transmission, but the European standards are not so much known. It is more convenient to use Russian hoses.

There are 2 types of hydraulic hoses used in industry: skive hoses and spiral hoses.

Skive hoses are used in hydraulic transmissions with high pressure – till 25 megapascals and with small radius of flexure.

Spiral hoses are used in hydraulic transmissions with the pressure of 30-40 megapascals and with constant cycle charge.

The European standards for skive hoses are DIN EN 853 and DIN EN 857, and they are almost similar to Russian GOST 6286. These standards are for the hoses which work with hydraulic mineral oils, engine propellant with temperatures from -40 to +100 C, and also for water and oil emulsion with temperatures from -40 to +70 C.

These requirements are convenient to Russian hydraulic hoses.

There are 4 types of hoses DIN EN 853:

1SN and 2ST – skive hoses1SN and 2SN – the same

construction, but thinner external rubber layer. This permits to armour the hoses without preparatory cleaning of external rubber layer.

The essential difference between foreign and Russian hoses is DN, which is fixed in inches. It is not always the same as Russian. For instance, the diameter of foreign hose with DN12 is 12,7 mm, which is larger than Russian one. At the same time DN10 and DN12 are 9,5 mm and 19 mm and they can allow 11% less liquid than Russian ones.

The testing of Russian hoses on leak resistance and rupture (megapascals):

DN Max pressure Leak resistance pressure

Rupture pressure

1ST and 1SN

2ST and 2SN

1ST and 1SN

2 ST and 2SN

1ST and 1SN

2ST and 2SN

5 250 415 500 830 1000 1650

8 225 400 450 800 900 1600

8 215 350 430 700 850 1400

10 180 330 360 660 720 1320

12 160 275 320 550 640 1100

16 130 250 260 500 520 1000

19 105 215 210 430 420 850

25 88 165 175 325 350 650

31 63 125 150 250 250 500

38 50 90 100 180 200 360

51 40 80 80 160 160 32

The marking of the hoses DIN EN 853 is the following:- Producer- Type- Caliber (in inches)- Standard- Nominal diameter- The last 2 figures of the producing year

The pressure is not marked, it is determined in the schedule. There are 2 types of DIN EN 857 hoses: 1SC and 2SC. Their characteristics are the same as DIN EN 853, but the bend radius is 40% less.

There are 4 types of spiral hoses DIN EN 856:- Type 4SP – 4-spiral skive hoses for middle-level pressure- Type 4SH – 4-spiral skive hoses for high pressure

- Type R12 – 4-spiral hose for long work with high temperature and middle-level pressure- Type R13 – 6-spiral hose for the most hard and long work with very high pressure. Its

production is limited.

ND Max pressure Leak resistance pressure, bar

Rupture pressure, bar

4SP 4SH R12 R13 4SP 4SH R12 R13 4SP 4SH R12 R13

16 350 - 276 - 700 - 552 - 1400 - 1104 -

19 350 420 276 345 700 840 552 690 1400 1680 1104 1380

25 280 380 276 345 560 760 552 690 1120 1520 1104 1380

31 210 325 207 345 420 650 414 690 840 1300 828 1380

38 185 290 172 345 370 580 344 690 740 1160 688 1380

51 165 250 172 345 330 500 344 690 660 1000 688 1380

ND, mm Min bend radius, mm

4SP 4SH R12 R13

6 150 - - -

10 180 - 130 -

12 230 - 180 -

16 250 - 200 -

19 300 280 240 240

25 340 340 300 300

31 460 460 420 420

38 560 560 500 500

51 660 700 630 830

DIN EN 856 have min temperature -40C

The characteristics of type 4SP:

Nominal inside diameter

Rupture pressure, bar Pressure according GOST

The number of cycles with Rmin

GOST EN 856

10 1400 1780 340 1000000

12 1360 1660 340 1000000

16 1360 1400 300 800000

19 1200 1400 250 800000

25 1000 1120 250 800000

The hydraulic hoses satisfy the requirements of the customers and can be used both in Russian and foreign machines. The quality and technical control is made during all periods of production. Then the hoses are tested on the testing stand.