HYDROMECHANICAL AUTOMATIC GEARBOX AND THE VEHICLE USING THE SAME

Abstract

A vehicle comprises a hydromechanical automatic gearbox, an automatic gear shift unit (12) connected to a pressure fluid feeding pump (15). The gearbox comprises an input shaft (4) extending from an engine, gearing (23) extending to each gear step, wherein the gearing (23) is mounted on the input shaft (4) and is as a central gear (2), located on the input shaft (4), meshing with gear wheels (3) of different gear steps having different diameters mounted on the input shaft (4) of a single hydraulic torque converter (5) comprising a pump (6) and a turbine (8) located accordingly on the input (4) and output (7) shafts thereof forming a flow path of pressure fluid, each of the hydraulic torque converter (5) is electronically and hydraulically linked to the gear shift unit (12) of the vehicle.

Claims

1. A hydromechanical automatic gearbox, comprising an input shaft extending from an engine and gearing extending from the input shaft to each gear step, wherein gearing is formed as a central gear, located on the input shaft, meshing with gear wheels of different gear steps having different diameters, each of the gear wheels is mounted on the input shaft of at least one hydraulic torque converter with centrifugal wheels of a pump and a turbine located accordingly on input and output shafts thereof forming a flow path of pressure fluid, and reactor variable blades located in the flow path, each of the hydraulic torque converters is electronically and hydraulically linked to the gear shift unit of the vehicle.

2. The automatic gearbox according to claim 1, wherein the transmission ratio between the central gear and a top gear corresponds to the following ratio: $n_p^{\max }.Math.\text{/}.Math.n_{\mathrm{En}}^{\max }\ge 0.62.Math..Math.\sqrt[a]{N_{\mathrm{En}}^{\max }},$ wherein n.sub.P.sup.max is a maximum rotational speed of the hydraulic torque converter input shaft working at the gear step; n.sub.Ab.sup.max is a maximum rotational speed of the engine shaft, N.sub.Ab.sup.max is a maximum engine capacity (in kilowatts).

3. The automatic gearbox according to claim 1, wherein step-down gears connected to a gear reducer (common for all hydraulic torque converters) mounted on the gearbox output shaft are located on the output shafts of the hydraulic torque converters.

4. The automatic gearbox according to claim 3, wherein the pump centrifugal wheel in hydraulic torque converters comprises profile blades where the centerline of the profile thereof is curved at 122°-135°, and the ratio between the value D.sub.2D of the outer diameter of the pump centrifugal wheel, and the value D.sub.1P of the inlet diameter of the profile blades thereof is: D.sub.2P/D.sub.1P=1.4-1.9.

5. The automatic gearbox according to claim 4, wherein the turbine centrifugal wheel in hydraulic torque converters comprises profile blades where the centerline of the profile thereof is curved at 110°-120°, and the ratio between the value D.sub.2T of the outer diameter of the turbine, and the value D.sub.1T of the inlet diameter of the profile blades thereof is: D.sub.2T/D.sub.1T=1.1-1.3.

6. The automatic gearbox according to claim 3, wherein the turbine centrifugal wheel in hydraulic torque converters is made with a bladeless conduit formed by centrifugal wheel discs of the turbine in front of profile blades thereof and having a diameter extension equal to the ratio: D.sub.1T/D.sub.2P=1.15-1.4, wherein D.sub.1T is a value of the inlet diameter of profile blades of the turbine centrifugal wheel, and D.sub.2P, is a value of the outer diameter of the pump centrifugal wheel.

7. The automatic gearbox according to claim 3, wherein reactor blades in hydraulic torque converters are configured to be fixed in a completely open, partially open or completely closed position.

8. The automatic gearbox according to claim 3, wherein the flow path of pressure fluid in hydraulic torque converters is connected to an air exhaust pump of the vehicle.

9. A vehicle, comprising an automatic gear shift unit connected to the feeding pump, which feeds pressure fluid from a pressure fluid container, at least one automatic gearbox and movers, wherein the automatic gearbox according to claim 1 is connected by the output shaft thereof to at least one of the movers, and movers may be wheels, propellers or tracks.

10. The vehicle according to claim 9, wherein it comprises the air exhaust pump connected with the air cavity in the pressure fluid container, and the air cavity is also connected to the flow path of pressure fluid of each hydraulic torque converter of the automatic gearbox.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 is a general arrangement of gear steps in AGB.

[0022] FIG. 2 is a general arrangement of AGB according to the invention.

[0023] FIG. 3 is a general arrangement of AGB with additional gear steps according to the invention.

[0024] FIG. 4 is an enlarged view of the area A in FIG. 2.

[0025] FIG. 5 is a scheme of curvature of the profile blades in the centrifugal wheel of the hydraulic torque converter pump.

[0026] FIG. 6 is a scheme of curvature of the profile blades in the centrifugal wheel of the hydraulic torque converter turbine.

[0027] FIG. 7 is a control scheme for movers of the vehicle with several AGB (2 AGB connected with movers at one side of the vehicle).

[0028] FIG. 8 is a control scheme for movers of the vehicle with several AGB (4 AGB, each of which is connected to one mover).

[0029] The AGB comprises a central gear 2 located on an engine shaft 1, and shifting gear wheels 3 having different diameters depending on the needed value of increasing the rotational speed mounted around the central gear and meshing therewith. Each of the gear wheels 3 provides shifting to at least one gear step. Gear wheels 3 are located on input shafts 4 of hydraulic torque converters 5. Each hydraulic torque converter 5 (cf. FIG. 2) comprises a pump centrifugal wheel 6 mounted on the shaft 4 and a turbine centrifugal wheel 8 mounted on an output shaft 7 thereof which form a pressure fluid flow path 9 in which variable reactor blades 10 and a unit 11 for rotating thereof in predefined position are mounted. An electro-hydraulic gear shift unit 12 controls pressure fluid feeding in the flow path 9 via a channel 13. The pressure fluid is fed from a pressure fluid container 14 by pressure fluid feeding pump 15. The draining of pressure fluid from flow paths 9 to the container 14 is performed via a channel 16. The vehicle also comprises an air exhaust pump 17 connected to the engine shaft 1 and via a channel 18 connected to the air cavity of the container 14 with the help of an intake pipe thereof. The pressure fluid feeding pump 15 is activated by the engine shaft 1 or by an additional electric motor 19. An ejector pump 20 providing pumping the pressure fluid via an air-to-water heat exchanger 21 is used for cooling the pressure fluid. In the air-to-water heat exchanger, the cooling of the pressure fluid is provided by air flow from an electric blower 22 and by incident flow during vehicle movement.

[0030] Via gearing 23 reducing rotational speed the turbine wheel 8 is connected to gear reducer 24 unified for all hydraulic torque converters 5 which is located on the AGB output shaft and has mainly 3 or 4 flows.

[0031] For providing AGB with increased number of gears on the single shaft 4 pump wheels 7 of two hydraulic torque converters are mounted (cf. FIG. 3). These two hydraulic torque converters allow performing modes of 4 power transmission steps.

THE PREFERRED EMBODIMENT OF THE INVENTION

[0032] The unit 11 for rotating reactor variable blades 10 in predefined fixed position may be a spring-loaded piston having working cavity connected to the pressure fluid feeding pump 15 via channels. The reactor variable blades 10 may be located in at least three fixed positions: with completely open flow area of the flow path 9 (working mode of the hydraulic torque converter 5 with maximum transmission of engine power and efficiency); with completely closed flow area of the flow path 9 (working mode of the hydraulic torque converter 5 with zero transmission of engine power and with dry internal cavity of the flow path for reducing mechanical losses during rotation of the wheels); with partially (20%) closed flow area of the flow path 9 (working mode of the hydraulic torque converter 5 with transmission of engine power of 20-25% less than maximum value and the efficiency at 85-86%). Said three fixed positions of variable blades allows performing modes of 2 steps of engine power transmission with different speed transmission ratio in AGB during operation of a single hydraulic torque converter 5.

[0033] A bladeless conduit 25 having a diameter extension D.sub.1T/D.sub.2P=1.15-1.4, wherein D.sub.1T is an inlet diameter of profile blades 26 of the turbine wheel 8, and D.sub.2P is an inlet diameter of profile blades 27 of the pump wheel 6 is formed in the hydraulic torque converters 5 between the blades of the pump wheel 6 and the blades of the turbine wheel 8. The conduit 25 is a bladeless slot diffusor having side limiting walls 28 rotating during operation of the hydraulic torque converter and being part of turbine wheel disks (FIG. 4). According to the law of circulation constancy, an effective decrease of flow rate circumferential components occurs in such bladeless slot diffusor causing increase of pressure in front of the turbine blades 26 and decrease of shock losses on the leading edge thereof

[0034] The pump centrifugal wheel 6 of the hydraulic torque converter 5 is provided with the profile blades 27 having a centerline curved at the angle φ°.sub.P=180°+Δ°.sub.P−(β°.sub.1P+β°.sub.2P)=122°−135°, wherein Δ°.sub.P is a radial angle between the leading and trailing edges of the pump wheel blades, β°.sub.1P is an angle of positioning of the profile centerline at the inlet diameter of the pump wheel, and β°.sub.2P is an angle of positioning of the profile centerline at the output diameter of the pump wheel. Whereas, the ratio between the outer diameter of the wheel and the inlet diameter of the blades is equal to: D.sub.2P/D.sub.2P=1.4-1.9 (FIG. 5).

[0035] The turbine centrifugal wheel 8 is also provided with profile blades having a centerline curved at the angle φ°.sub.T=180°+Δ°.sub.T−(β°.sub.1T+β°.sub.2T)=110°-120°, wherein Δ°.sub.T is a radial angle between the leading and trailing edges of the blades; β°.sub.1T is an angle of positioning of the profile centerline at the inlet diameter of the turbine wheel, and β°.sub.2T is an angle of positioning of the profile centerline at the output diameter of the turbine wheel. Whereas, the ratio between the outer diameter of the wheel 8 and the inlet diameter of the blades 26 thereof is equal to: D.sub.2T/D.sub.2T=1.1-1.3 (FIG. 6).

[0036] The abovementioned implementation aspects of the pump and turbine wheels provide exceptionally high efficiency of the hydraulic torque converter reaching 92-93% at the transmission ratio of turbine rotational speed and pump rotational speed n.sub.P equal to: n.sub.T/n.sub.P=0.95-1.0.

[0037] The single AGB electro-hydraulic gear shift unit 12 provides gear shifting and control of units 11 for rotating reactor variable blades 10 connected to the pressure fluid feeding pump 15 via channels and connected to internal cavities of flow paths 9 of the hydraulic torque converter 5 of each gear step via channels 13. Depending on the vehicle driving speed and the operational mode of the engine the unit 12 connects the pump 15 to the flow path 9 and the unit 11 for rotating reactor variable blades in one operating hydraulic torque converter 5 simultaneously disconnecting the feeding pump 15 from flow paths 9 of other hydraulic torque converters 5 (other gear steps) fixing the reactor blades in a closed position.

[0038] The internal cavities of flow paths 9 of all hydraulic torque converters used in the AGB are connected to the air cavity of the pressure fluid container 14 along the outer diameter thereof via channels 16 also being connected to the intake pipe of the air exhaust pump 17 for exhausting the air from the air cavity of the container 14 to the atmospheric environment driven by the engine shaft 1 or by the autonomous electric motor 19. Thereby, in the hydraulic torque converters 5 disconnected by the electro-hydraulic gear shift unit 12, the rotation of the pump and turbine wheels 6 and 8 in flow paths 9 due to exhausting the air by the pump 17 is performed at lower pressures and lesser hydromechanical losses. Such losses if necessary may be further decreased by using a free wheeling clutch providing only one-way transmission of torque moment in the gear reducer extending from the turbine shaft 7.

INDUSTRIAL APPLICABILITY

[0039] The implementation scheme and structure of the abovementioned type of drum automatic gearbox transmitting rotational speed and torque moment from vehicle engine has a small weight and reduced diametric and axial dimensions. It allows positioning on one vehicle 29 both one AGB 30 providing simultaneous change of speed for all movers 31 in the form of wheels, screw or tracks, and several identic AGB. For example, as shown in FIG. 7, two AGB 30 can be mounted on one vehicle, each of which is connected to movers 31 located at one side of the vehicle longitudinal axis. This allows performing maneuvers previously impossible for the particular vehicle, for example, such as a sharp turn on a dime. As shown in FIG. 8, a vehicle may have as many AGB 30, as many movers 31 it has. In this case, each ABG shifts gears for one mover. All AGB are controlled by one gear shift unit of the vehicle.

[0040] Such scheme allows using movers with different velocity ratios providing significant increasing of maneuverability and high stability of the entire vehicle. Moreover, such scheme allows activating the reverse of the wheels at a high speed, thus proving a hydraulic braking.

[0041] The aspects of the provided technical solution open up new horizons for creating vehicles of new generations.