阅读说明：本技术 用于车辆的静压驱动系统 (Hydrostatic drive system for a vehicle ) 是由 D·甘布齐 N·F·穆西亚那 F·纳塔利 N·特萨罗 于 2019-07-17 设计创作，主要内容包括：本发明涉及一种用于车辆的静压驱动系统(1)。该系统(1)包括静压传动单元,该静压传动单元包括液压马达(2),该液压马达设有容纳体(3)和驱动轴(4),该驱动轴绕初级轴线(A)旋转地支承在容纳体(3)内部,并且设有突出到容纳体本身的外部的终端部分(4a)。系统(1)还包括车桥(6),该车桥(6)包括用于差动装置(8)的壳体外壳(7),该差动装置用于将驱动扭矩传递到两个半桥(9),这两个半桥承载相应的轮子并绕横向于初级轴线(A)的次级轴线(B)旋转。差动装置(8)设有绕次级轴线(B)旋转的带齿的锥形驱动齿圈(11),该锥形驱动齿圈与驱动轴(4)操作地相关联,用于通过联接构件(12)传递驱动扭矩。本发明的独特特征包括以下事实：该联接构件包括锥形小齿轮(12),该锥形小齿轮(12)围绕初级轴线(A)旋转地与驱动轴(4)刚性地相关联,并且直接与齿圈(11)齿轮连接,小齿轮(12)沿着驱动轴(4)的终端部分(4a)定位。(The invention relates to a hydrostatic drive system (1) for a vehicle. The system (1) comprises a hydrostatic transmission unit comprising a hydraulic motor (2) provided with a containing body (3) and a drive shaft (4) supported rotatably about a primary axis (A) inside the containing body (3) and provided with a terminal portion (4a) projecting outside the containing body itself. The system (1) also comprises an axle (6), the axle (6) comprising a housing shell (7) for a differential (8) for transmitting a driving torque to two half-bridges (9) carrying respective wheels and rotating about a secondary axis (B) transversal to the primary axis (A). The differential device (8) is provided with a toothed conical drive ring gear (11) rotating about a secondary axis (B), operatively associated with the drive shaft (4), for transmitting a drive torque through a coupling member (12). The unique features of the present invention include the fact that: the coupling member comprises a conical pinion (12), the conical pinion (12) being rigidly associated with the drive shaft (4) in rotation about the primary axis (a) and being directly geared with the ring gear (11), the pinion (12) being positioned along a terminal portion (4a) of the drive shaft (4).)

1. A hydrostatic drive system (1) for a vehicle, comprising

A hydrostatic transmission unit comprising a hydraulic motor (2) equipped with a containing body (3) and a drive shaft (4) supported rotatably about a primary axis (A) inside said containing body (3) and equipped with a terminal portion (4a) projecting outside the containing body itself; and

an axle (6) comprising a housing shell (7) for a differential (8) for transmitting a driving torque to two half-bridges (9) carrying respective wheels and rotating about a secondary axis (B) transversal to said primary axis (A);

said differential device (8) being equipped with a toothed conical drive ring gear (11) rotating about said secondary axis (B), operatively associated with said drive shaft (4) for transmitting a drive torque through a coupling member (12);

characterized in that said coupling member comprises a conical pinion (12), said conical pinion (12) being rigidly associated with said drive shaft (4) in rotation about said primary axis (A) and directly meshing with said ring gear (11), said pinion (12) being positioned along said terminal portion (4a) of said drive shaft (4).

2. System (1) according to claim 1, characterized in that said pinion (12) is associated with said drive shaft (4) in the proximity of the free end of said terminal portion (4 a).

3. System (1) according to claim 1 or 2, characterized in that said pinion (12) and said drive shaft (4) are made integrally in a single piece.

4. System (1) according to claim 1 or 2, characterized in that said pinion (12) is associated with said terminal portion (4a) of said drive shaft (4) by rigid connection means (13).

5. System (1) according to claim 1 or 2, characterized in that said pinion (12) is directly associated with said terminal portion (4a) of said drive shaft (4).

6. System (1) according to claim 1, characterized in that said primary axis (A) and said secondary axis (B) are coplanar.

7. The system (6) according to claim 1, characterized in that said primary axis (a) and said secondary axis (B) are orthogonal to each other.

8. System (1) according to claim 6 or 7, characterized in that said toothed ring (11) and said pinion (12) have respective straight or helical teeth.

9. System (1) according to claim 1, characterized in that said primary axis (a) and said secondary axis (B) are offset, said ring gear (11) and said pinion (12) having hypoid teeth.

10. System (1) according to claim 1, characterized in that said casing (7) is provided with a flange (17) for connection to said containing body (3), said terminal portion (4a) of said drive shaft (4) being crossed by said flange (17).

Technical Field

The subject of the invention is a hydrostatic drive system for a vehicle.

Background

Various types of industrial and non-industrial vehicles are known, which vehicles employ a drive system comprising a hydrostatic transmission unit for the rotary actuation of drive wheels through interposed axles equipped with a differential for distributing the driving torque from a longitudinally extending drive shaft to two driven, transversely extending half-bridges (half-shafts) connected to each wheel.

These hydrostatic transmission units essentially comprise a hydraulic circuit that uses the pressure of the working fluid output from the pump to actuate a hydraulic motor equipped with a rotary drive shaft for the output.

The connecting propeller shaft is interposed between the drive shaft of the hydraulic motor and the differential of the axle.

Typically, the drive shaft is provided with a terminal portion comprising a groove profile, while the drive shaft (transmission shaft) comprises, at a first end, a female seat provided with a corresponding groove profile for connection with the rotary shaft. In addition, an outer safety shield is provided for coupling the rotating shaft and the drive shaft together.

The propeller shaft also provides a bevel pinion gear associated with a second end, opposite the first end, which meshes with the bevel ring gear for rotationally actuating the differential and the half-bridge connected thereto.

The casing of the axle therefore provides a tubular accessory through which the drive shaft inserted is rotatably supported by means of relative bearings, equipped with a flange for connection to the hydraulic motor housing.

This known solution is not without drawbacks, including the fact that the presence of the propeller shaft brings about a significant increase in the axial extension of the system, with consequent installation problems, in particular in compact vehicles.

Furthermore, the need to provide a mechanical connection between the drive shaft and the rotating shaft of the hydraulic motor, as well as to rotatably support the drive shaft itself, increases the number of necessary parts, leads to complexity in manufacturing and assembly, and increases production costs.

Furthermore, the fact that a housing for the drive shaft must be provided complicates the implementation of the axle housing and increases the associated production costs.

Disclosure of Invention

The main task of the present invention is to eliminate the above-mentioned drawbacks of the known art by devising a hydrostatic drive system for vehicles which makes it possible to significantly reduce the longitudinal footprint, facilitating installation in vehicles with compact dimensions without involving specific design phase adaptations.

Within the scope of this technical task, another object of the present invention is to reduce the number of components employed, to simplify the production cycle and to reduce the cost thereof. In particular, the invention makes it possible to reduce the number of rotary support bearings employed.

It is another object of the present invention to simplify the construction of the component parts, particularly with respect to the axle housing.

Another object of the invention is to propose a simple structure which, in addition to a relatively limited cost, has a relatively easy practical actuation, is safe to use and functionally effective.

This task and all the purposes are achieved by means of a hydrostatic drive system for vehicles of the type comprising a hydrostatic transmission unit comprising a hydraulic motor provided with a containing body and a drive shaft supported in rotation in said containing body about a primary axis and provided with a terminal portion projecting outside the containing body itself, and an axle comprising a housing for housing a differential device for transmitting a driving torque to two half-bridges supporting respective wheels and rotating along a secondary axis transversal to said primary axis, the differential device being provided with a toothed conical driving ring gear rotating about said secondary axis, operatively associated with said drive shaft for transmitting the driving torque through a coupling member, characterized in that, said member comprises a conical pinion rigidly associated with said drive shaft in rotation about said primary axis and directly meshing with said ring gear, said pinion being positioned along a terminal portion of said drive shaft.

Drawings

Further characteristics and advantages of the invention will become better apparent from the detailed description of some preferred but not exclusive embodiments of a hydrostatic drive system for vehicles, illustrated by way of non-limiting example in the accompanying drawings, wherein:

fig. 1 is a top plan schematic view of a hydrostatic drive system for a vehicle according to the present invention, partially broken away in correspondence with the coupling area between the drive shaft and the differential;

FIG. 2 is an enlarged schematic view of a portion of FIG. 1, including the coupling region between the drive shaft and the differential;

FIG. 3 is a schematic partial cross-sectional view according to section III-III of FIG. 1;

FIG. 4 is a schematic partial cross-sectional view of section IV-IV according to FIG. 1, according to an alternative embodiment of the invention

FIG. 5 is a top plan schematic view of a hydraulic motor provided in the system according to the present invention, partially broken away in correspondence with the drive shaft;

fig. 6 is a top plan schematic view of an alternative form for implementing the motor of fig. 5.

Detailed Description

With particular reference to these figures, a hydrostatic drive system for a vehicle is generally indicated at 1.

The system 1 comprises a hydrostatic transmission unit, which is not shown or described in detail since it is of a known type. The unit mainly includes a hydraulic system that actuates the hydraulic motor 2 using the pressure of the working fluid (hydraulic oil) output from the pump.

The hydraulic motor 2 comprises a substantially box-shaped containing body 3, inside which are housed components for converting the hydraulic energy of the working fluid into mechanical energy transmitted to the output drive shaft 4, wherein these components are not shown or described in detail, since they are of known type.

The drive shaft 4 is supported rotatably inside the containing body 3 about a primary axis a coinciding with the longitudinal axis of the shaft itself and having a terminal portion 4a projecting towards the outside of the body itself.

Within the containing body 3, a conventional bearing-type or similar rotary support member 5 is provided for the drive shaft 4.

In the drawing is shown an italic (enclosed-body) hydraulic motor 2 with an axial piston. However, this does not exclude that the system 1 may provide for the use of different types of hydraulic motors 2, such as axial piston motors with a swash plate, radial piston motors, gear motors or gerotor motors (orbital motors). Furthermore, the hydraulic motor 2 may have a fixed or variable displacement.

The system 1 also comprises an axle 6, the axle 6 having a housing shell 7 for a differential device 8, the differential device 8 being intended to transmit a driving torque to two half-bridges 9, the two half-bridges 9 carrying, at their respective ends, a hub 10, the hub 10 being intended to support a respective wheel (not shown) and being arranged along a secondary axis B transverse to the primary axis a.

The differential device 8 comprises a toothed, conical ring gear 11, which ring gear 11 extends around the secondary axis B and is operatively associated with the drive shaft 4 for transmitting the drive torque through a coupling member 12.

According to the invention, the coupling member is constituted by a conical pinion 12, the conical pinion 12 being rigidly associated with the drive shaft 4 about the primary axis a and directly meshing with a toothed ring 11, the toothed ring 11 being positioned along the terminal portion 4a of the drive shaft 4.

In this way, it is avoided to interpose additional coupling members between the drive shaft 4 and the ring gear 11 along the primary axis a, thus containing the required space of the system 1 in the axial direction.

Preferably, the pinion 12 is positioned in the vicinity of the free end of the terminal portion 4a of the drive shaft 4.

In a preferred form of actuation, the pinion 12 is directly associated with the free end of the terminal portion 4a of the drive shaft 4.

The pinion 12 can be integrally formed in a single piece with the drive shaft 4 (fig. 6), or can be associated with a terminal portion 4a of the shaft itself by rigid connection means 13.

In fig. 1 to 5, the pinion 12 has an axial hole 14 into which the terminal portion 4a is inserted. Preferably, the rigid connection means 13 are of the interference and friction type and comprise a cotter pin (cotter)15, which cotter pin 15 is inserted into a respective hollow 16 defined between the wall of the hole 14 and the outer sheath of the drive shaft 4.

However, this does not exclude that different embodiments of the rigid connection means may be provided, which may for example provide for the use of other systems using obstructions and/or friction or using expansions (displations), or having a grooved profile.

In one possible embodiment (fig. 3), the primary axis a and the secondary axis B are coplanar and incident to each other, preferably orthogonal. In this case, the teeth of the ring gear 11 and the pinion gear 12 may be straight, as shown, or may be helical.

In an alternative embodiment (fig. 4), the primary axis a and the secondary axis B are offset. In this case, the teeth of the ring gear 11 and the pinion gear 12 are hypoid.

The housing 7 comprises a flange 17 for connection to the containing body 3, through which flange the terminal end 4a of the drive shaft 4 passes.

The terminal portion 4a is freely inserted through the flange 17 or a rotation supporting member for the drive shaft 4 is not inserted in the housing 7.

In this way, the structure of the system 1, and in particular of the casing 7, is simplified with respect to known solutions, thus reducing the number of components employed and simplifying the realisation and assembly of the system 1.

Further, it should be noted that the system 1 may be installed at the front or rear of the vehicle when it is used, depending on the requirements of the particular application.

In practice it has been found how the above-described invention achieves the proposed aim, and it is particularly emphasized that the system according to the invention is characterized by a limited extension along the primary axis, compared with known solutions, so as to facilitate its use in compact vehicles.

Furthermore, the solution according to the invention is characterized by a simplified structure and a smaller number of components compared to known solutions.

Furthermore, the system according to the invention can be implemented with different types of hydraulic motors and axles, so that it can be versatile as the characteristics of the specific application vary.

The invention as conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept.

Moreover, all the details may be replaced with other technically equivalent elements.

In practice, the materials used, as well as the shapes and the contingent dimensions, may be any according to requirements without thereby departing from the scope of protection of the following claims.