RU2280568C2 - Vehicle driving axle - Google Patents

Abstract

FIELD: transport and agricultural engineering.

SUBSTANCE: proposed driving axle has housing, drive shaft, final drive in form of drive pinion and driven gear, differential case central hole fitted on bearings in housing and rigidly connected with driven gear, two driven shafts with screw thread, member movably connecting driven shafts by meshing with screw thread through solids of revolution and passing through central hole of differential case coaxially with case for axial displacement in said hole, and springs. Cavities, for instance, semi-spherical ones, are made in central cylindrical hole of differential case. Connecting member is made in form of cylindrical bushing on outer surface of which longitudinal grooves are made, for instance, with semispherical bottom, parallel to its axis, and on ends of inner surface cavities are made, for instance, semispherical ones. Ends of driven shafts from side of differential case are provided with outer thread and are installed in bushing for rotation. Bushing can be displacement both relative to differential case by means of solids of revolution, for instance, balls installed by one half in cavities of inner cylindrical surface of differential case and by other half, in longitudinal outer grooves of bushing and relative to driven shafts, by means of solids of revolution, for instance, balls installed in cavities of bushing and contacting with thread of driven shafts. Driven shafts are provided with stops to limit travel of bushing along driven shaft made, for instance, in form of beads on shafts and coil springs placed between beads and end faces of bushing. Cavities are made on end faces of driven shafts arranged inside differential case in which solids of revolution, for instance, balls are fitted.

EFFECT: simplified design, operation and repair of driving axle improved efficiency of its operation.

3 cl, 3 dwg

Description

The invention relates to differential devices, for the construction of the drive axle of vehicles and can be used in the automotive industry, in aircraft and ship transport, and in agricultural engineering.

Driving axles of wheeled vehicles are known, in which a differential in the form of a planetary gear transmission with bevel gears is used to provide different speeds of rotation of the driving wheels, for example when cornering [1]. When driving on curved sections of the road, such a differential provides a slower rotation of the inner drive wheel, which helps to avoid slipping of this drive wheel and thereby prevent increased wear of its tires, as well as power losses due to difficult turning of the vehicle. A drawback of such drive axles is that when one of the drive wheels hits a slippery section of the road, it starts to slip, while the other drive wheel stops rotating and therefore is unable to budge a vehicle, such as a car. If one of the driving wheels of the car starts to slip while driving along a slippery section, then conditions are created that cause side skidding of the car.

Known drive axle of the car, in which to eliminate the above disadvantages using a cam differential of increased friction [2]. A cam differential provides torque transmission to both drive wheels and eliminates the possibility of one drive wheel stopping when the other is slipping. However, due to increased friction in the elements of the cam differential, the power consumption increases, and it is not sensitive to small turns, at which the inner drive wheel stalls. This disadvantage is absent with the above differentials [1]. Therefore, cam differentials of limited friction are not widespread, and widespread use in driving axles is preserved for planetary differentials with bevel gears.

The drive axle of a vehicle is known in which a differential in the form of a planetary gear transmission with bevel gears is used and in which automatic differential lock control in the form of a set of additional devices is used to eliminate the above disadvantages of such differentials [3]. This complex includes a system for responding to a given angle of rotation of the vehicle with a steering angle sensor associated with the steering element, a control element connected to the power cylinder of the differential lock gear clutch and a power source, two tachometric sensors connected to the corresponding drive wheels of the vehicle and electrically connected to the electronic unit, as well as the first and second comparison elements having additional inputs for setting the threshold level, and control Differential conductive element is configured as a first directional control valve further has second and third control valves, hydraulic valve, and so on. Due to the great complexity of the design, such a device for automatically controlling the differential lock in the driving axles of vehicles has not received practical application.

The drive axle of a vehicle is known in which a limited-slip differential is used [4]. It consists of a housing with fingers placed in it, on which satellites are mounted. The gears of gear pumps are connected to the satellites, and eight gear pumps are located in the differential housing, the gears of which are mounted coaxially with the gears of the axle shafts. Four driven gears are engaged with each pinion gear, the outer cylindrical surfaces of the pump housings are connected by radial bends to the valleys of the pinion gears. These cylindrical surfaces are covered by rings connected to the crankcase (housing) of the main gear, in addition, the rings in the lower part have windows. Due to the great complexity of the design, this limited-slip differential has not received practical application in driving axles.

The driving axle of cars with manual control of the differential differential lock is known by means of a gear clutch, the drive of which contains a plug connected to a piston rod located in an attachment located outside the drive axle housing [5, 6]. In such a drive axle, the drive of the gear clutch for locking the differential is an autonomous unit attached to the crankcase of the drive axle, making assembly of the drive axle easier. However, if the drive of the gear clutch is used to lock the differential, it may be damaged if the vehicle is accidentally hit by a major obstacle while it is driving on the road. In addition, clumps of dirt can accumulate on the specified attachment and in the space between it and the drive axle housing, increasing the unsprung mass of the vehicle and contributing to corrosion.

All known constructions of drive axles of vehicles, based on the use of differentials in the form of planetary gears with bevel gears, have two major drawbacks: first, they require the use of special devices to lock the differential in order to prevent slipping of the drive wheels of the car, which greatly complicates the design whole; secondly, they increase the radial dimensions of the structure, as a result of which the car's ground clearance is reduced, which is an important indicator of their cross-country ability.

Closest in design to the claimed invention is the Sitkaryov drive axle for a vehicle, which includes a crankcase, a drive shaft, a final drive in the form of gearing of the drive and driven gears, a differential housing made with a central hole located on the bearings in the crankcase and rigidly connected to the driven gear, two driven shafts, one end fixed to the differential housing for rotation, and springs [7]. Coaxial cylindrical cavities with a screw thread are made in the driven shafts from the side of the differential case, the central hole of the differential case is made shaped. An element made in the form of a rod, coaxially connected to the driven shafts, passes through this hole, having in its middle part a cross section corresponding to the configuration of the hole, and mounted to move along this axis along this axis, and the cylindrical ends of the connecting element are made with recesses, which rolling bodies are installed, for example, balls, which ensure the engagement of this element, i.e. rod, with internal screw thread cavities of driven shafts. A spring is installed in each driven shaft between the bottom of its cavity and the end face of the element.

This design of the drive axle eliminates the need to use both the differential currently used, based on a planetary gear transmission with bevel gears, and a special device for self-locking or forced locking, as it uses the principle of limited self-regulation of rotation speeds of two driven shafts proposed by the author. The disadvantage of this drive axle is the relative complexity of the design.

The task to which the invention is directed is to simplify the design and manufacturing technology of the drive axle with automatic self-regulation of the rotation speeds of two driven shafts (half shafts), as well as increasing its efficiency.

The author first showed the theoretical basis of the sufficiency of limited self-regulation of these speeds for the first time by the calculation below. As can be seen from figure 1, when the car is rotated through an angle α, the outer wheel will move along the radius R with respect to the turn, and the inner wheel will move along the radius (Rt) with respect to the turn, where t is the track gauge, i.e. distance between wheels. The number of revolutions of the outer wheel n _n when turning the machine at an angle α is determined by the formula:

n _n = Rα / d,

and the inner wheel n _in respectively

n _in = (Rt) α / d,

where d is the diameter of the wheels.

The outer wheel will make more revolutions by an amount

n _n-in = n _n -n _in ,

which is determined by the formula

n _n-a = Rα / d- (Rt) α / d = αt / d.

Those. the value of n _nv does not depend on the radius of rotation R! This conclusion is unexpected for many.

Since for trucks t / d≈1, then with an angle of rotation α = -90 ° = π / 2 we get n _n-in = 1.57, and with an angle α = 180 ° = π we get n _n-in = 3 ,fourteen. Since for cars t / d≈1.5, then at an angle of rotation α = 90 ° = π / 2 we get n _n-in = 2.36, and at an angle α = 180 ° = π we get n _n-in = 4.71.

It turns out the second unexpected conclusion for everyone: when turning the car to move in the opposite direction, the outer wheel will make the number of revolutions compared with the inner wheel only 3.14 more turns for trucks and 4.71 revolutions for cars!

These two conclusions (Sitkarev evidence) allowed the author to propose both a prototype design and a new design for the drive axle, providing the required limited self-regulation of the drive wheel speeds.

This problem is achieved due to the proposed design, which provides, in comparison with the prototype, firstly, the use of a connecting element in the form of a sleeve, and, secondly, instead of an internal screw thread in the cavities of the driven shafts, the external screw thread on the ends of these shafts is on the side differential cases. The proposed bridge in comparison with the prototype is simpler and more reliable in design, more technological in manufacturing, as well as in operation and repair.

The essence of the proposed technical solution is that in the drive axle for the vehicle, including the crankcase, the drive shaft, the main gear in the form of gearing of the drive and driven gears, a differential housing located on the bearings in the housing, rigidly connected to the driven gear and having a central gear a hole, two driven shafts made with a screw thread, an element movably connecting the driven shafts by means of its engagement with their screw thread through rolling elements and passing through the central The hole of the differential case with the possibility of axial movement in this hole, and the spring, according to the claimed invention, the central hole of the differential case is made in the form of a cylindrical surface on which are located recesses, for example, hemispherical, the connecting element is made in the form of a cylindrical sleeve, on the outer surface of which longitudinal grooves, for example, with a hemispherical bottom, parallel to its axis, and at the ends of the inner surface of which grooves are made, for example, a hemisphere the ends of the driven shafts on the side of the differential case are provided with an external thread and rotatably mounted in the sleeve, while the sleeve can be moved relative to the differential case by means of rolling bodies, for example balls installed by one half in the recesses of the inner cylindrical surface of the differential case and the other half - in the longitudinal outer grooves of the sleeve, and relative to the driven shafts by means of rolling bodies, for example balls installed in the recesses of the sleeve and the contour threaded driven shafts. The driven shafts are equipped with limiters for moving the sleeves along them, for example, in the form of beads made on these shafts, and spiral springs located between the beads and the ends of the sleeve. And at the ends of the driven shafts located inside the differential housing, recesses are made in which rolling bodies, for example balls, are installed.

Solutions that are characterized by a combination of features of the claimed invention were not found in accessible sources of information, and a comparative analysis of the proposed device with the designs of known differential devices allows us to conclude that the proposed design differs from the known ones by the presence of new significant features, i.e. about its compliance with the criterion of "novelty."

In the study of other technical solutions, the influence of the combination of distinctive features of the claimed invention on the simplification of the design was not revealed. This indicates the creative nature of the proposed solution, i.e. on its compliance with the criterion of "inventive step".

The invention is illustrated by drawings (Fig.1-3).

Figure 2 schematically shows a General view of the proposed device with a longitudinal vertical section, and figure 3 is a transverse section of the proposed device.

The claimed drive axle includes a crankcase, in the bearings 1 of which a drive shaft 2 is installed, the main gear is in the form of a bevel gearing of the drive gear 3 and the driven gear 4, the gear 4 being rigidly connected to the differential housing 5. In this housing, mounted on the bearings 1 of the crankcase, a cylindrical hole 6 is made, on the inner surface of which there are recesses 7 and in which a sleeve 8 is installed, on the outer surface of which there are longitudinal grooves 9, while the sleeve 8 is able to move in the hole 6 by means of balls 10 installed by one half in the recesses 7, for example, hemispherical, and the other half in the longitudinal grooves 9. From the opposite ends of the sleeve 8 on its inner cylindrical surface 11 I have Xia recess 12, for example, hemispherical. The driven shafts (half shafts) 13 and 14 from the side of the differential housing 5 are made with an external screw thread 15. At the same time, balls 16 are installed in the recesses 12 on the sleeve 8, which are in contact with the thread 15 of the driven shafts 13 and 14. At the ends of the driven shafts located inside the housing 5 of the differential, a recess 17 is made, for example, hemispherical, in which a ball 18 is mounted defining the necessary clearance between the ends of the driven shafts and thereby enabling rotation of one driven shaft relative to another. Flanges 19 are made on each driven shaft 13 and 14, which, firstly, through an emphasis on the crankcase bearing 1 prevent the displacement of these shafts away from the differential housing 5, and secondly, they limit the amount of movement of the sleeve 8 along these shafts by twisting it or twisting on their screw threads 15. For the same purpose, spiral springs 20 are installed on these shafts between the shoulders 19 and the ends of the sleeve 8.

The work of the proposed device is as follows.

The movement of the machine occurs when the rotation is transmitted from the drive shaft 2 through the drive gear 3 to the driven gear 4, which drives the differential housing 5 and through the hole 6 through the balls 10 through the balls 8, and it transmits torque to the driven shafts 13 and 14 through the balls 16, providing internal engagement of the sleeve 8 with a screw thread 15 of these shafts. The screw threads 15 are made on these shafts opposite in direction and are oriented so that when the machine moves forward, the balls 16 tend to move through the screw thread 15 of the axle shafts 13 and 14 to each other, but this is prevented by the ball 18 installed in their end face, so the balls 16 make rotate together with the sleeve 8 of the axle shafts 13 and 14. When the machine moves backwards, the balls 16 tend to move these half-shafts away from each other through the screw thread 15, but this is prevented by the collars 19 resting against the corresponding bearings 1 of the crankcase. Therefore, the balls 16 are forced to rotate together with the sleeve 8 of the driven axles 13 and 14 in the opposite direction. When turning the machine, the sleeve 8 will move coaxially relative to the semiaxes 13 and 14, providing this (as described in the prototype [7]) the difference in the speeds of rotation of these semiaxes and respectively the driving wheels of the machine, since the proposed design of the drive axle carries out the following relationship of speeds its axis:

n _n + n = 2n _{to d,}

wherein n = n _{n d n} + 0,5n _a, n _a = n _{d n--0,5n a, n-a n} = αt / d,

where n _d is the number of revolutions of the driven gear and, accordingly, the differential housing, the remaining designations are given above. Coaxial movement of the sleeve 8 relative to the axle shafts when turning the machine causes the extension of one and compression of the other spring 20.

For example, when the truck moves forward and turns it 90 ° to the right, the left wheel (on the axle shaft 13) is external when turning and will rotate faster, and the rotation of the right wheel (on the axle shaft 14) will slow down accordingly. In this case, the left end of the sleeve 8 will move 0.5n h _-in = 0.785 turns to the right along the left half shaft 13 to the middle of the differential case 5, and the right end of the sleeve 8 will simultaneously move along the right half shaft 14 to the right from the middle of this case to the same 0.785 turnover. This means that the left half shaft 13 additionally receives rotation (due to the relative unscrewing of the sleeve 8 from the left half shaft 13) by the same 0.785 turns, and the right half shaft 14 reduces the rotation (due to the relative twisting of the sleeve 8 into the right half shaft 14) by these same 0.785 turnover. On the whole, the left driving wheel will make more turns when turning 90 ° than the right one, only n _n-in = 1.57 turns (as shown above by calculation).

After the machine makes a turn, before the start of the next turn, it is necessary to ensure that the sleeve 8 returns to its original (i.e., middle) position. This will be facilitated, firstly, by gradually balancing the load on the drive wheels during the end of the turn, secondly, by the action of the springs 20, and thirdly, by briefly disconnecting the load on the driven shafts, for example by discharging gas to change speed (which almost always happens) since when removing the load (torque) on the balls 16 and, accordingly, on the driven shafts 13 and 14, the resistance to movement of the sleeve 8 to its original (or middle) position will decrease. Therefore, after each turn or passage of a slippery place, to return the sleeve 8 to its original position, at least a short-term forward movement or a short-term load shedding during movement (for switching speeds or specifically) will be enough.

Since it is structurally undesirable to overestimate the magnitude of the axial displacements of the sleeve (so as not to increase the dimensions of the structure), it is sufficient for cars to accept the condition of a single continuous rotation of not more than 270 °, i.e. accept, according to the above calculation, the maximum rotation of the sleeve relative to the axle shafts (0.5n _n-in ), equal to only 2.4 turns for trucks and 3.6 turns for cars.

With the proposed drive axle, it is not recommended that the car rotate continuously in one place (it is not intended for this), since when the sleeve 8 is moved to the extreme position, the wheel speed self-regulation stops and they will already rotate forcibly at the same speed. Those. the proposed design already ceases to fulfill its intended function when turning more than the angle α _max , the value of which is enough to take 270 ° for both conventional and special-purpose machines.

As in the prototype [7], the main gear can be made in the form of a bevel or cylindrical gear transmission or a belt gear.

So, the proposed design of the Sitkaryov drive axle for a vehicle provides, as in the prototype, the necessary range of self-regulation of the speeds of rotation of the driven shafts, almost always sufficient, for example, for cars, and in comparison with the prototype has the following advantages:

1) the design of the bridge is simplified, firstly, due to the simplification of the design of the element movably connecting the driven shafts (there is no removable tip - item 10 in figure 2 in the prototype [7]), and secondly, due to the lack of the need for bearings between the differential housing and these shafts (item 20 in figure 2 in the prototype), since their role is played by a sleeve with balls installed in its recesses;

2) the technology of manufacturing, operation and repair of the bridge is simplified, since it is not necessary to make rather deep cavities in the driven shafts, and the screw thread is not made inside these cavities, but on the outer surface of these shafts;

3) increases the reliability of the structure, because in the prototype, firstly, deep cavities in the driven shafts reduce their torsional and bending strength, and secondly, a removable tip (item 10 in figure 2 in the prototype) reduces the structural strength of the element movably connecting driven shafts;

4) the radial size of the bridge is reduced, since it is not necessary to place bearings between the differential housing and driven shafts (item 20 in FIG. 2 in the prototype), which helps to reduce the mass of the bridge and increase ground clearance, i.e. improve car patency.

Information sources

1. Kozhevnikov S. N. Theory of mechanisms and machines. / M .: - Engineering. - 1969, p. 307-309.

2. Borovsky Yu.I. and other Device cars / M. - Higher. school., 1983, p.119.

3. Application of Ukraine No. 95125096 dated 01.12.95, cl. 5 V 60 K 17/20, Bull. No. 3, 1998.

4. Patent of Ukraine No. 23883 A dated 08/31/98, cl. 6 F 16 H 1/44, Bull. No. 4, 1998.

5. Japanese application No. 60-580, cl. F 16 H 1/445.

6. Application in EPO No. 256746, cl. F 16 H 1/44.

7. Application for invention No.20076084, filed in Ukrpatent 07/01/2003, cl. B 60 K 17/00; F 16 N 1/00 - prototype.

Claims (3)

1. The drive axle for the vehicle, including the crankcase, drive shaft, the main gear in the form of gearing of the drive and driven gears, a differential housing located on the bearings in the housing, rigidly connected to the driven gear and having a Central hole, two driven shafts made with by a screw thread, an element movably connecting the driven shafts by means of its engagement with their screw thread through the rolling elements and passing through the central hole of the differential housing with the possibility of axial movement I’m in this hole, and the spring, characterized in that the central hole of the differential housing is cylindrical and on this cylindrical surface there are recesses, for example, hemispherical, the connecting element is made in the form of a cylindrical sleeve, on the outer surface of which there are longitudinal grooves, for example, with hemispherical bottom parallel to its axis, and at the ends of the inner surface of which are made recesses, for example, hemispherical, the ends of the driven shafts from the side of the differential housing sleep wives are external thread and rotatably mounted in the sleeve, while the sleeve can be moved relative to the differential housing by means of rolling bodies, for example balls installed by one half in the recesses of the inner cylindrical surface of the differential housing, and the other half in the longitudinal outer grooves of the sleeve, and relative to the driven shafts by means of rolling bodies, for example balls installed in the recesses of the sleeve and in contact with the thread of the driven shafts. 2. The driving bridge according to claim 1, characterized in that the driven shafts are equipped with limiters for moving the sleeves along them, for example, in the form of shoulders made on these shafts and coil springs located between the shoulders and the ends of the sleeve. 3. The drive axle according to claim 1, characterized in that at the ends of the driven shafts located inside the differential housing, recesses are made in which rolling bodies, for example balls, are installed.

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