RU2667436C2 - Assembly of radial piston hydraulic machine comprising optimised housing - Google Patents

Abstract

FIELD: machine building.SUBSTANCE: invention relates to the design of housings for hydraulic machines. Hydraulic circuit (4) comprises hydraulic machine (42), housing (110) and auxiliary components assembled on hydraulic machine (42). Hydraulic machine (42) and auxiliary components are accommodated in housing (110). Housing (110) is composed of two connected chambers (112, 114), of which one chamber (112) is designed for high pressure and other chamber (114) is designed for low pressure. Components (427, 426, 421) of hydraulic machine (42) and auxiliary components operating at high pressure are grouped and placed in high pressure chamber (112). Components (420, 425) of hydraulic machine (42) and auxiliary components operating at low pressure are grouped and placed in low pressure chamber (114). Invention also relates to a vehicle comprising such an assembly.EFFECT: reduction in the weight of the transmission.14 cl, 4 dwg

Description

Technical field

The present invention relates to the field of hydrostatic transmissions and, more specifically, to designs of crankcases for hydraulic machines.

In particular, the invention can be used in the implementation of auxiliary hydraulic drive in a self-propelled vehicle.

State of the art

Performing a hydrostatic transmission in a vehicle requires the installation of various components, including one or more hydraulic machines that can operate as a pump or motor, systems for distributing, feeding, filtering and storing oil.

The result of this multitude of components is high mass and large overall dimensions, which can create problems when designing a vehicle.

In addition, it is necessary to connect these various components, which leads to many hydraulic hoses and electrical connections, creating, in particular, problems of tightening the hoses.

To limit the overall dimensions associated with the components and their connections, it has already been proposed to group some functions, such as pump pumping and oil filtration functions, into a common crankcase.

However, the total mass of the components remains significant.

SUMMARY OF THE INVENTION

An object of the present invention is to reduce the weight of components for performing a hydrostatic transmission for a vehicle and simplifying the integration of a hydrostatic transmission in a vehicle.

In this regard, the subject of the invention is a node comprising:

- sump

- a hydraulic machine configured to connect to a hydraulic system, and

- auxiliary components for equipping a hydraulic machine,

moreover, the hydraulic machine and auxiliary components are located in the crankcase,

wherein the node is characterized in that:

- the crankcase is made of two connected chambers, of which one chamber is capable of withstanding high pressure, and the other chamber is capable of withstanding low pressure, and

- while the components of the hydraulic machine operating at high pressure, as well as auxiliary components operating at high pressure, are grouped and placed in the chamber of the high pressure housing, while the components of the hydraulic machine operating at low pressure, as well as auxiliary components operating at low pressure, grouped and placed in a low pressure crankcase chamber.

As will be understood from the following description, the invention allows to reduce the mass of the crankcase assembly, since the crankcase chamber operating under low pressure can be made, in particular, of another material or may have a wall thickness less than the crankcase chamber operating under high pressure.

The invention also relates to a vehicle comprising such an assembly mounted on a chassis.

Brief Description of the Drawings

Other characteristics, objects and advantages of the invention will be apparent from the following description, which is not restrictive, with reference to the accompanying drawings, in which:

FIG. 1 is a diagram of a hydraulic system of a vehicle comprising a unit in accordance with an embodiment of the invention,

FIG. 2 is a perspective view of an exterior of an assembly in accordance with an embodiment of the invention,

FIG. 3 schematically depicts a portion of a crankcase assembly in accordance with an embodiment of the invention and

FIG. 4 depicts a grouping diagram of high pressure functional components and low pressure functional components in respective designated portions of chambers in accordance with the invention.

Detailed disclosure of at least one embodiment of the invention

In FIG. 1 shows a hydraulic diagram of a vehicle V. Preferably, but not limited to, vehicle V is a light vehicle such as a car.

Vehicle V comprises a chassis and two axles 10, 20, each of which carries two wheels 12, 13 and 22, 23, respectively.

Two axles 10, 20 define the main direction D of the chassis, which corresponds to the direction of movement of the vehicle.

Further, the vehicle comprises a main engine M, typically a heat engine, a clutch 2 and a gearbox 3, connecting the engine with one of the axles 10, 20 for its drive.

In FIG. 1, the main engine drives the front axle 10, known as the drive axle, and the rear axle 20, is known as the drive axle.

Further, the vehicle comprises an auxiliary hydraulic device, preferably a hydrostatic system, transmitting power from the driving axis 10 to the driven axis 20. Moreover, the vehicle comprises a first hydraulic machine 40 mounted on the chassis and connected to the driving axis 10, and a second hydraulic machine 42 installed on the chassis and connected to the driven axis 20. Two hydraulic machines 40, 42 are connected to each other by hydraulic pipes 4a, 4b, forming a hydraulic system 4, and are reversible, that is, they can operate as a hydraulic pump s or hydraulic motors.

Each hydraulic machine 40, 42 contains all the components necessary for its operation both as a pump and as a motor, from oil supply to the drive shaft. In particular, each hydraulic machine 40, 42 contains the following proprietary components:

- shaft and bearing (bearings),

- a mechanical-hydraulic or hydromechanical energy conversion system, in particular pistons, a cylinder block and a cam;

- a distributor designed to distribute the fluid to the energy conversion system;

- if necessary, means of mechanical connection or braking.

Preferably, the hydraulic machine 40 on the drive axle 10 operates in the pump mode and is driven by the heat engine M via the clutch 2 and the gearbox 3 to generate a power flow of the hydraulic machine 42, which operates in the motor mode.

The hydraulic system 4 further comprises a system 43 to feed the hydraulic machines 40, 42. This system 43 includes a make-up pump 44, which draws the oil necessary for feeding the system from the crankcase 40 of the engine or from the corresponding reservoir (the reservoir is not shown in Fig. 1 to simplify the illustration). The make-up pump 44 is driven by an electric motor 49. The output of the pump is connected through a filter 47 to check valves 50 and 52, leading respectively to pipelines 4a and 4b.

Pressure limiters 51, 53 are parallel to valves 50 and 52, respectively. The same pressure limiter 54 is located between the outlet of the filter 47 and the inlet of the make-up pump 44.

The hydraulic system 4 may also include a valve 45 controlled by the control device 46, designed to selectively connect to the crankcase of the motor 40, which forms a reservoir, pipelines 4A and 4b, connecting hydraulic machines 40 and 42, to perform the drainage function of the system.

In FIG. 1 also shows the differentials 14 and 24 on the front and rear axles 10 and 20, respectively.

In FIG. 2 shows a unit 100 in accordance with one embodiment of the invention, designed for permanent installation on a vehicle, for example, by mounting on a vehicle chassis, and comprises a hydraulic machine, for example, one of the hydraulic machines 40, 42. In the following description, it is assumed that the node 100 contains a hydraulic machine 42 of the driven axis 20.

The assembly 100 comprises a crankcase 110 accommodating the hydraulic machine 42, and also, in addition to the differential 14, all or part of the components of the make-up system, such as the make-up pump 44, the electric motor 49, the filter 47, two check valves 50 and 52, and restrictors 51, 53 and 54 pressure. In addition, the sump 110 can accommodate all or part of the components used to drain the system, that is, in this case, the valve 45.

The invention is not limited to this specific embodiment. It covers many alternative exemplary embodiments, and the assembly may contain auxiliary components for the hydraulic machine 42 in the crankcase 110, which are components of the hydraulic system associated with the hydraulic machine but not involved in the energy conversion performed by the hydraulic machine. In particular, auxiliary components are not components that are mechanically driven by a hydraulic machine.

In the context of the invention, preferably the hydraulic machines 40 and 42 are respectively a pump and a radial piston hydraulic motor.

The applicant has already proposed many models of radial piston hydraulic pumps and hydraulic motors.

Thus, preferably in the context of the invention and as shown in FIG. 3, the radial-piston hydraulic machine forming the motor 42, contains in the crankcase a hydromechanical transducer, consisting of:

- multilobal cam 420, preferably made on the inner surface of the crankcase element, while the cam is stationary,

- a block of 422 cylinders, made so that it undergoes relative rotation inside the crankcase;

- a shaft 424 connected to the cylinder block 422, so that the shaft rotates, while preferably the shaft is hollow and spline so as to drive the shaft or half shaft carrying the wheel,

- radial sliding plungers 423 guided in respective cylinders of cylinder block 422 and abutting against the wave profile of cam 420, and

- a distributor 426, configured to sequentially and in a controlled manner to supply fluid from the pump to the plungers 423, so that the plungers successively abut against the petals of the cam 420. This causes the cylinder block 422 and its associated elements to rotate relative to the crankcase.

In FIG. 3, reference numeral 427 denotes a crankcase cover that hermetically seals the housing accommodating the distributor 426, and reference numeral 421 denotes the radially inner part of the cylinder block 422, called the hydraulic base, which receives fluid from the distributor 426 and sequentially feeds the cylinders with plungers 423 placed therein.

Since such a system is reversible, the hydraulic machine forming the pump 40 preferably has the same construction as the described motor 42. This means that since the shaft 424 of the pump 40 or a member mechanically connected to it is driven by the heat engine M through the gearbox 3, the interaction plungers 423 with a multi-leaf cam 420 of the pump 40 sequentially creates pressure in the cylinders, so that the hydromechanical converter formed by the machine 40 is not a motor, but a hydraulic pump.

Those skilled in the art will recognize that some components of the motor 42 are exposed to high pressure, while some other components of the same motor are exposed to low pressure.

In particular, the housing enclosed by the cover 427, in which the distributor 426 is placed, the distributor 426 and the hydraulic connection 421 are subjected to the high pressure generated by the pump 40 when it is actuated.

On the other hand, for example, the part of the motor 42 that forms the rotation bearing 425 for the shaft 424, as well as the cam 420 are subject to low pressure (lubrication function).

By way of non-limiting example, the so-called “high” pressure to which the distributor and the hydraulic base are exposed is 300 to 500 bar, preferably 300 to 450 bar, and preferably 400 bar.

As for the "low" pressure, it is from 5 to 30 bar and preferably has the order of 9 bar.

More specifically, in accordance with the invention in this example, the crankcase 110 consists of two chambers 112 and 114 connected to each other. In the chamber 112 of the crankcase creates high pressure. Another chamber 114 of the crankcase is designed to operate under low pressure.

In addition, components, such as 427, 426 and 421 hydraulic machines 42, which operate under high pressure, as well as auxiliary components, such as 45, 50, 51, 52, and 53, which operate under high pressure, are grouped together and located in the chamber 112 high-pressure sumps, while components, such as component 420 of hydraulic machine 42, which operate under low pressure, as well as auxiliary components, for example, 44, 47, 49 and 54, which operate under low pressure, are grouped together and located in chamber 114 crankcase low pressure.

This separation of the functional components operating under high pressure and the functional components operating under low pressure and the grouping of these two categories of functional components in the respective chambers 112 and 114 of the crankcase are shown schematically in FIG. four.

In particular, in FIG. 2 shows a chamber for an electric motor 39, which drives a make-up pump 44, and a chamber for a filter 47 in a crankcase chamber 114.

According to the first embodiment of the invention, both crankcase chambers 112 and 114 are made as a single part, that is, they are made as a common single crankcase. However, in the context of the invention, the crankcase chamber 114 subjected to low pressure has a smaller thickness than the crankcase chamber 112. Thus, the invention makes it possible to carry out a lighter sump 110 than in solutions known from the prior art.

For example, for two cast iron crankcase chambers, the wall thickness of the crankcase chamber 112 may be 15 mm, while the wall thickness of the crankcase chamber 114 is of the order of 5 mm.

According to a second embodiment of the invention, the two chambers 112 and 114 of the crankcase are made in the form of separate chambers with an appropriate thickness for high pressure and for low pressure, as indicated for the first embodiment, and attached to each other in their relative operating positions by suitable means, such as threaded connections or bolts 115, as shown in FIG. 2.

In the context of the second embodiment, both crankcases 112 and 114 may be made of the same material. However, preferably, they are made of various materials selected to withstand high pressure and low pressure, respectively.

For example, the crankcase chamber 112 may be made of cast iron or steel, while the crankcase chamber 114 may be made of aluminum.

The wall thickness of the chambers 112 and 114 of the crankcase is provided in accordance with the selected materials and operating pressures.

It goes without saying that the invention is not limited to the described exemplary embodiments, but embraces all alternatives within the spirit of the invention.

Claims (21)

1. A hydraulic system (4), comprising: - a hydraulic machine (42), - case (110) and - auxiliary components (44, 45, 47, 49, 50, 51, 52, 53, 54), equipping the hydraulic machine (42), moreover, the hydraulic machine (42) and auxiliary components (44, 45, 47, 49, 50, 51, 52, 53, 54) are located in the crankcase (110), however, this system is characterized in that: - the crankcase (110) is made of two connected chambers (112, 114), of which one chamber (112) is designed to operate under high pressure, and the other chamber (114) is designed to operate under low pressure, and - while the components (427, 426, 421) of the hydraulic machine (42) operating under high pressure, as well as the auxiliary components (45, 50, 51, 52, 53) operating under high pressure, are grouped and placed in the chamber (112) high-pressure crankcase, while the components (420, 425) of the hydraulic machine (42) operating under low pressure, as well as auxiliary components (44, 47, 49, 54) operating under low pressure, are grouped and placed in the chamber (114) of the crankcase low pressure. 2. The hydraulic system according to claim 1, characterized in that the auxiliary components comprise components of a make-up system for the hydraulic system. 3. The hydraulic system according to claim 1 or 2, characterized in that the chamber (114) of the low-pressure crankcase accommodates a make-up pump (44), an associated motor (49) and a filter (47). 4. The hydraulic system according to claim 1 or 2, characterized in that the high-pressure sump chamber (112) accommodates check valves (50, 52) and pressure limiters (51, 53). 5. The hydraulic system according to claim 1 or 2, characterized in that the auxiliary components comprise components for draining the hydraulic system. 6. The hydraulic system according to claim 5, characterized in that the chamber (112) of the high-pressure housing accommodates the drain valve (45). 7. The hydraulic system according to any one of paragraphs. 1, 2, 6, characterized in that the chamber (112, 114) of the crankcase are made of one piece of material in the form of a single common element. 8. The hydraulic system according to claim 7, characterized in that the low pressure chamber (114) of the crankcase is designed so that its thickness is less than the thickness of the high pressure chamber of the crankcase (112). 9. The hydraulic system according to any one of paragraphs. 1, 2, 6, characterized in that the two chambers (112, 114) of the crankcase are made in the form of two separate, initially separated chambers, the thickness of which is provided for high pressure and low pressure, respectively, and which are connected in a relative operating position. 10. The hydraulic system according to claim 9, characterized in that the two chambers (112, 114) of the crankcase are made of two different materials selected to withstand high pressure and low pressure, respectively. 11. The hydraulic system according to claim 8, characterized in that the chamber (112) of the high pressure housing is made of cast iron or steel, while the chamber (114) of the low pressure housing is made of aluminum. 12. The hydraulic system according to any one of paragraphs. 1, 2, 6, 8, 10, characterized in that the hydraulic machine (42) is made in the form of a radial piston machine, in which the housing is hermetically closed by a cover (427) and which contains a distributor (426), moreover, a distributor (426) and a hydraulic the base (421) is located in the chamber (112) of the high pressure housing, while the part of the hydraulic machine (42) that forms the rotation bearing (425) for the shaft (424) and cam (420) is located in the chamber (114) of the low pressure housing. 13. A vehicle equipped with a hydraulic system according to any one of paragraphs. 1-12. 14. The vehicle according to claim 13, characterized in that it contains two axles (10, 20) and a main engine (M), and the hydraulic system (4) contains a first hydraulic machine (40) connected to the drive axle (10), the main engine (M) drives the first hydraulic machine (40), the second hydraulic machine (42) connected to the driven axis (20), and the hydrostatic power transmission links the first hydraulic machine (40), which forms the pump, and the second hydraulic machine (42), which forms motor, make-up pump (44), connected to the filter (47) and with non-return valves (50, 52) and from the limiter mi (51, 53) of pressure, while the second hydraulic machine (42) is made in the form of a radial piston machine, in which the housing is hermetically closed by a cover (427) and which contains a distributor (426), the distributor (426) and the hydraulic base (421 ), as well as check valves (50, 52) and pressure limiters (51, 53), are located in the chamber (112) of the high-pressure housing, while the part of the second hydraulic machine (42), which forms the rotation bearing (425) for the shaft (424) and the cam (420), as well as the feed pump (44) and the associated filter (47), are located in the chamber (114) of the crankcase who pressure.

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