DE2433990A1 - DIFFERENTIAL GEARS IN PARTICULAR FOR LOCOMOTIVES - Google Patents

Description

Differential gear especially for locomotives

The invention relates to a drive transmission system for Railway vehicles and in particular to transmission systems for Vehicles propelled by a gas turbine engine.

Each bogie of a locomotive usually has two shafts that are both driven, and there is therefore the requirement that there is no mechanical connection between the two driven shafts to prevent torque blocking between to avoid the waves. One method that meets this requirement is to mount an electric motor on each shaft and powered by an alternator on the locomotive. Another option is to use a single Provide gas turbine engine with two mechanically independent outputs.

The invention also provides a single power source, such as a gas turbine, which drives the two shafts through a differential gear drives, wherein the differential gear is designed so that a certain slip take place between the two output shafts can.

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According to the invention, a differential gear with a housing and at least two pairs is more meshing with one another Gears are provided which are rotatable in the housing, wherein two output gears are also provided and each one of the meshing gears with one of the driven gears and wherein an oil supply is provided to the oil To supply pairs of meshing gears and this oil then ejected to a point outside the housing will.

The oil can pass through a channel in a shaft that connects to a the output gears are connected to a closed chamber within the housing in communication. The oil can then are fed to both sides of the meshing gear pairs via check valves. The oil can overflow from the housing openings or pressure valves are discharged.

The oil can also be fed to the gear wheel, which is between the output gears and the gear pair is arranged and there can be suitable numbers of pairs of meshing gears be provided for each output gear.

The differential gear is preferably a spur gear formed, wherein the meshing gear pairs are spur gears, the bearings of which are arranged in the housing. The case is driven by a power source, preferably in the form of a gas turbine engine.

The spur gears have extensions that correspond to the output gears mesh and the shafts on which the driven gears are mounted, the shafts of a drive bogie drive.

An exemplary embodiment of the invention is described below with reference to the drawing.

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- 3 - In the drawing show:

Pig. 1 shows a schematic representation of a known embodiment of a spur gear differential gear;

FIG. 2 is a partial perspective view of the differential gear according to FIG. 1;

3 is a sectional view of an embodiment of a Differential gear according to the invention;

Fig. 4 is a partial front view of the differential of Figure J5J.

Figure 5 is a plan view of part of the differential according to Figure 3 and 4;

6 shows a section along the line 6-6 according to FIG.

The differential gear 10 according to Figures 1 and 2 has two sun gears 12 and 14, which sit on drive shafts 16 and 18, respectively, which are rotatably mounted in the housing 20. In addition, two pairs of intermediate gears 22, 24 are rotatably mounted in the housing 20, the < sit on countershafts 22a, 24a and each have two spur gears 22b, 22c and 24b, 24c. The sun gear 12 meshes with the spur gear 22b and the spur gear 22c meshes with the spur gear 24b and the spur gear 24c meshes with the sun gear 14. The housing 10 is driven about the axis A-A by means not shown and, although not shown in the drawing, Further tooth connections are arranged around the circumference of the sun gears 12, 14.

When the housing 20 is stopped and the sun gear 12 is

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rotates clockwise, then the pinions 22 rotate counterclockwise and the sun gear 14 also rotates counterclockwise. Therefore, if one of the sun gears 12, 14 rotates faster than the housing 20, then that rotates other sun gear slower than the housing by a corresponding amount.

The torque acting on the sun gear 12 is a result of the pressure of the teeth of the pinion 22b and this pressure seeks to cause the pinion assembly 22 with its shaft 22a to rotate. This tendency acts the pressure between the Pinions 22c and 24b against. The pressure between the pinions 22c, 24b seeks to rotate the pinion 24b with the shaft 24a and the pressure between the teeth of the pinion 24c and the sun gear 14 counteracts this tendency. Assuming that the Pinion assemblies 22,24 are fixed relative to the housing 20 or rotate evenly in the housing 20, then the must on each Pinion arrangement acting pressures be the same. Therefore, all pressures between sun gears 12, l4 and the pinion assemblies 22, 24 act to be the same, and the torque that acts on the sun gears and accordingly also that on the drive shafts 16.18 effective torque must be the same.

When considering the possibility of driving two railroad drive shafts a problem with a mechanical transmission is that if the driven wheels also have only small differences in diameter, a torque builds up between the shafts, so that a shaft is in is trying to turn in the wrong direction and the other shaft is moving forward at too high a speed.

One solution to this problem is to use a differential gear according to Figure 1 and 2 to use. Such an arrangement

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however, it has the disadvantage that the torque cannot exceed the torque of the shaft, its wheels have the least adhesion. When shaft slip occurs, the one that bears the slipping wheels Shaft accelerates to very high speeds because of the coefficient of sliding friction becomes effective and not the coefficient of static friction, so that there is a much lower frictional force and the result may be burning of the rails.

The present invention is described below with reference to FIG Figure 3 Dis β described, wherein a spur-epicyclic gear is shown which has been modified in certain ways to solve such problems.

Reference is made below to FIG. 3, which is analogous to FIG. The individual parts according to Figure 3 have been numbered that they matched with equivalent components of the differential of FIG. 1 and these equivalent parts work in the in the same way as described and are therefore not explained again.

The housing consists of several circular plates 30, which are provided with appropriate cutouts to accommodate the various sun gears, planet gears, shafts and oil passages that are enclosed in the housing. The plates 30 are held in their position by two end plates 32 and three clamping bolts y \ , which the latter are clamped between the end plates. The housing is rotatably mounted in bearings 36 in a gear box 38, only a part of which is shown, and two ring gears 40 are fixed on the housing 20 via the end plates 3 ^. The ring gears 40 can be selectively driven by a motor, not shown. For example, the ring gears 40 can be through a mechanism

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are driven * as shown in British patent application 22987/7 ² J-. Here, the ring gears 40 are constantly in engagement with spur gears which can be selectively connected to the motor, one of the ring gears 40 being in direct engagement while the other ring gear 40 meshes with a deflection wheel, so that the housing 20 is clockwise as well as can be driven counterclockwise.

The shaft 16 has a bore 50 into which a hollow bolt 52 is inserted, which forms an oil channel 54, which is only schematically is shown and will now be described. Hydraulic oil contained in a sump 56 can be the same can like the sump for the gear box 38 or as shown, can be formed separately from this, is pumped along the oil channel by a circulation pump 58, which only Housing 20 holds full of oil and the oil through the hollow pin 52 Via a connector βθ and openings in the end plates J52 the shaft 16 and the bolt 52 can enter. An oil cooler and an oil vent (not shown) are at the top of the power supply of the sump 56 is provided and the pump 58 can not Have illustrated overflow valve in order to avoid that the pump sets the oil in the housing 20 under pressure, so that excess oil is withdrawn into the sump. The oil comes out of the End of shaft 16 between the ends of shafts 16 and 18 after the engaged pinion pair 22c, 22b. How schematic Shown in FIG. 4 are three pairs of pinion arrangements 22, 24 spaced around the circumference of the sun gears 12, 14 and hydraulic oil is supplied to the engaged pinion gears of each pair. Details of the hydraulic circuit are only shown for a pair of meshing pinions 22c, 24b (Figure 6).

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With respect to each pair of meshing pinions 22c, 24b, two check valves 62, 64 are provided, both of which allow hydraulic oil to flow out only from the center of the shaft 16 to supply oil to both the inlet and outlet of the meshing pinions 22c, 24b . In addition, two pressure relief valves 66, 68 are arranged in the housing 20, so that one pressure relief valve is located on both sides of the pinion gear that is in engagement.

In normal operation, the differential gear works in the usual way Manner as described with reference to FIGS. 1 and 2. The hydraulic oil is pumped along the oil path 54 and has no effect on the operation of the differential. If, however, there is a relative rotation between the shafts 16, 18, the meshing pinions 22c, 24b operate as hydraulic gear pumps and the oil flows freely on the suction side the engaged pinion engages via the check valve 62 and is prevented by the check valve 64 from to flow back after the wave. The oil on the pressure side is via the pressure relief valve 68 to the outside of the Housing 20 and then discharged to the sump 56. When the oil cannot flow through the meshing pair of teeth via valve 64, it can flow out of the housing via the pressure relief valves 66 and 68 are pumped.

When the pinions 22c, 24b work as a hydraulic gear pump (this occurs when a noticeable torque difference occurs two driven wheel axles), the pinions rotate like a normal differential gear, but generates the Effect of the pinion pumping the oil creates a restoring torque, so that large torque differences are caused by the action of the gear pump can be maintained due to the relative rotation of the two output shafts. In the same way, small differences of Output speeds, which are due to small differences in the wheel diameter

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knives are caused or by different grinding characteristics continuously maintained with only small differences in torque and without any Build up a torque.

All desired characteristics of the torque difference can be used depending on the differential speed (rpm) between the output shafts are generated when the pressure relief valves are designed in a suitable manner, which can be done simply by having them as simple openings in the gear pumps are arranged. In addition, the pressure relief valves can respond to changes in temperature and on the mass flow of the hydraulic oil to allow adaptation to various operating conditions and temperature changes, which can occur from a cold start up to operating temperature.

The hydraulic pumping effect can be increased by using the same technique in the meshing gears between Sun gears 12,14 and pinions 22b, 24c is provided.

There are only three pairs of 22, 24 meshing pinions provided, but several pinion arrangements can be provided

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Patent claims:

Claims (1)

Claims Differential gear with a housing and at least one pair of intermeshing intermediate gears which are rotatably mounted in the housing and with two output gears, one of the pairs of meshing intermediate gears each meshing with one of the output gears, characterized in that an oil supply along an oil path ( 5 ² I-) after the one pair of meshing wheels (22c, 24b) is provided and that this pair of wheels (22c, 24b) works as a gear pump, and the oil it delivers through a throttle point (68) from the housing , (20) is discharged. Differential gear according to claim 1, characterized in that the oil path (5 ² O) comprises a hollow bolt (52) in a shaft (50) which carries one of the output gears (12), that a closed chamber between the ends of the shafts (16, 18) is provided and that a check valve (62) and flow restrictors (68) are provided. Differential gear according to claims 1 or 2, characterized in that that the oil path (54) is shunted from the closed one Chamber via a check valve (64) to the high pressure side of the engaged wheels (22c, 24b). Differential gear according to claims 1, 2 or 3 * characterized in that the oil path (54) shunts from the low pressure side after the high pressure side of the engaged wheels (22c, 24b), the shunt 509807/0751 leads over the flow throttle device (66) . 5. Differential gear according to one of the preceding claims, characterized in that the engaged wheels (12, 22b, 14, 24c) are supplied with oil and work as gear pumps. 6. Differential gear according to one of the preceding Expectations, characterized in that the operating characteristics of the flow restrictors (66 _} 68) can be changed in accordance with a parameter of the oil. 509807/0751 Leersette