Field of the Invention

The present invention relates to an automatic gearbox designed for use in light-duty and heavy-duty vehicles, including heavy-duty dump trucks, or any equipment which has an engine.

Background of the Invention

Romanian Patent No. 126056 dated March 29, 2013 discloses a type of automatic gearbox with two shafts and ball couplings, where the engine power is transmitted through clutches. One disadvantage of this technology is that it does not work well in high power applications.

The present invention solves the above-mentioned technical problem by providing an automatic gearbox, which enables power transmission through ball couplings and controls that will lead to increased reliability and a wider range of use.

Summary of the Invention

According to the present invention, the automatic gearbox eliminates the previously mentioned disadvantage because it includes a ball hydraulic clutch joined to a clutch shaft fitted with helical gears which engage the gear rims of pressure ball couplings. The gear rims are mounted on an intermediate shaft and are fitted with gear rims attached to helical gears. In turn, both the gear rims and the helical gears on the intermediate shaft engage the helical gears and gear rims of ball couplings located on the output shaft. The two shafts are fitted with hydraulically connected pressure chambers, which are supplied with pressurized transmission fluid from a hydraulic distributor. This distributor is fitted with a hydraulic accumulator and a pressure controller connected in turn to an oil pump. The pump is fitted with a helical gear engaged by another helical gear.

The drums connected to the gear rims are fitted with radial stepped holes with different radii, arranged on one single row. In these holes, pistons reciprocate, each fitted with a seat where pressure balls are positioned and retained radially by a retainer ring. The drums connected to the gear rims are fitted with pistons and balls arranged in two rows with half a step shift. The drum connected to the gear rim is fitted with three rows of pistons and balls, the middle row arranged with half a step shift from the side rows. The pressure ball coupling which is connected to the gear rim and to a drum is fitted with a row of radial hydraulic passages communicating with radial rectangular seats in which cylindrical pistons reciprocate. The pistons have rectangular ends and they are biased by coil springs. The coil springs are mounted on a rectangular metal element fitted with an axial passage. The cylindrical pistons make contact with balls.

The pressure controller consists of a primary element and a secondary element, joined together by helical threading. A sliding rod, which is fitted with a lockup plate pressed by a coil spring attached to the secondary element, moves inside and along the axes of the two elements. Inside the sliding rod there is an axial passage, which enables the hydraulic fluid to pass from the threaded port of the primary element to the secondary element. The hydraulic accumulator comprises a cylindrical element fitted with a threaded port and a chamber for the pressurized fluid. The cylindrical element is assembled by threading with several secondary elements assembled, in turn, by threading. A sliding rod moves inside and along their axes. The rod is fitted with a piston which reciprocates inside the cylindrical elements. Moreover, the sliding rod is also fitted with circumferential passages in which plates are engaged. The plates are pressed by coil springs arranged in pairs and sitting independently on the secondary elements, thus creating a force couple.

According to the present invention, the automatic gearbox has the following advantages:

- Shifting gear without shock;

- Reduced fuel consumption;

- Instantaneous gear shifting;

- Longer service life;

- Reduced size; and

, - Due to locking between gears, the vehicle is also locked and braking is no longer necessary. In order to start the vehicle, simply pressing the accelerator is sufficient. Brief Description of the Drawings

The following is a preferred embodiment of this invention, in connection to Figures 1- 13, wherein:

Figure 1 is an overall sectional view of the automatic gearbox, according to the present invention;

Figure 2 is a sectional view taken through the axis of the final shaft of the automatic gearbox, according to the present invention;

Figure 3 is an axial sectional through the coupling with two rows of balls, position B; Figure 4 is a perspective view of the gear rims from Figure 1, position 34, 35 and 36 Figure 5 is a side view of the drum, position 43;

Figure 6 is a sectional view through the plane of line I - 1 of the drum with two rows of holes;

Figure 7 is a perspective view of the retainer ring, position 45;

Figure 8 is an axial sectional view through the coupling with one row of balls, position A;

Figure 9 is a perspective view of the gear rims from Fig. 1, position 9, 10, 17 and 18;

Figure 10 is a side view of the drum, position 11 ;

Figure 1 1 is an axial sectional view through the plane of line II - II;

Figure 12 is an axial sectional view through the plane of line III - III;

Figure 13 is an axial sectional view through the plane of line IV - IV;

Figure 14 is an explanatory table of gear engagement, according to the present invention.

Detailed Description of the Invention

According to the present invention and as shown in Figure 1 , the automatic gearbox shown here consists of a ball hydraulic clutch 1 fitted with a helical gear 2 which engages another helical gear 3 connected to the oil pump 4. Moreover, the ball hydraulic clutch is attached to a clutch shaft 5 which, in turn, is attached to helical gears 6 and 7 and is supported by a conical bearing 8.

The helical gears 6 and 7 engage two gear rims connected to pressure ball couplings A (Fig. 8). Inside each one, there is a drum 1 1 attached to an intermediate shaft 12. The drum 11 is fitted with radial stepped holes a with different radii, inside which pistons 13 reciprocate. The pistons 13 are each fitted with a sealing ring (not shown) and a seat b containing pressure balls 14. In addition, pressure chambers 15 and 16, with respectively one and two hydraulic circuits (Fig. 1) are mounted on the intermediate shaft 12. Also mounted on the intermediate shaft 12 are gear rims 17 and 18, sustained by ball couplings (not shown) and helical gears 19, 20, 21, 22 and 23. The intermediate shaft 12 is sustained by conical bearings 24, 25 and 26 and is fitted with passages (not shown) connecting the pressure chambers 15 and 16 to the drums (which in turn are connected to the above-mentioned ball couplings).

According to the present invention, the automatic gearbox is also fitted with an output shaft 27 sustained by conical bearings 28, 29 and 30 and fitted with helical gears 31 and 32, as well as gear rims 33, 34, 35, 36 and 44. The latter are sustained by the ball couplings B (Fig. 3), C (Fig. 2) and respectively D (Fig. 1 1). The drums connected to the ball couplings B are fitted with pistons 37 and balls 38 arranged on two interposing rows. The gear rim 33 is sustained by a ball coupling C arranged on three rows, similar in design to couplings A (Fig. 1 1) and B (Fig. 12). On the output shaft 27, there is also a pressure ball coupling D connected to the gear rim 44. The ball coupling also has a drum 46 attached to the output shaft 27. The drum 46 is fitted with a row of radial hydraulic passages f, with rectangular seats g (Fig. 13) through which cylindrical pistons 47 reciprocate. Each of these cylindrical pistons 47 have a rectangular end h fitted with a sealing gasket. The pistons 47 are biased by coil springs 48 (Fig. 14), each of which are in turn sustained by a rectangular metal element 49, fitted with an axial passage i through which the cylindrical section of the cylindrical pistons 47 reciprocate. These rectangular elements 49 lock the rectangular seats g from the outside of the drum 46. An adequate force is exerted on the balls 50 due to the large surface area of the rectangular end h of the cylindrical pistons 47 upon which fluid pressure is also exerted. This technical solution significantly minimizes the number and size of the balls 50 and thus, the size of the entire coupling assembly.

These gear rims 33, 34, 35, 36 and 44 are engaged with the helical gears 19, 20, 21 , 22, and 23 connected to the intermediate shaft 12 (Fig. 1), while the helical gears 31 and 32 are engaged with the gear rims 17 and 18 connected to the intermediate shaft 12. Moreover, there is a pressure chamber 39 mounted on the output shaft 27. The pressure chamber 39 consists of a single hydraulic circuit and a block of four pressure chambers 40 (Fig. 2) with different hydraulic circuits. The pressure chambers 40 are connected to axial passages hi (Fig. 2), which are, in turn, connected to circumferential passages 41 (Fig. 6) and to radial stepped passages 42 (Fig. 6), located in the drums 43 (Fig. 6) and 46 (Fig. 11) connected to ball couplings B and respectively D.

For each of the four types of ball couplings A, B, C and D the position of the balls 14, 38 and 50 is radially limited by retainer rings 45 (Fig. 7). The rows of holes d on the retained rings match the number of balls and have locking arms e so that the rings may be flexible and retain the balls 14, 38 and 50.

According to the present invention, the automatic gearbox also includes a pressure controller E (Fig. 12) comprising a primary element 51 and a secondary element 52 (the threaded port k is connected to the high pressure hydraulic circuit), both of them cylindrical and threaded together. Inside and along their axes, a sliding rod 53 moves by translation. The sliding rod 53 is fitted with an axial passage j which enables the passage of the pressurized fluid from a threaded port k of the primary element 51 to a chamber m of the secondary element 52. The sliding rod 53 is also fitted with a lockup plate n, which is pressed toward the threaded port k by a coil spring 54 mounted on the secondary element 52.

Because the ends of the sliding rod 53 are in the primary element 51, and the secondary element 52, respectively, and because the pressurized fluid presses on these ends with different diameters, the sliding rod 53 remains in the chamber m of the secondary element 52 (Fig. 12). Due to the pressure of the coil spring 54 on the lockup disk n, the sliding rod moves toward the threaded port k of the primary element 51, opening the circuit to pressurized fluid that is aspirated through a threaded port o towards another threaded port p by the oil pump 4 shown in Figure 4. The free movement of the fluid is enabled by a circumferential passage r located inside the sliding rod 53. In turn, the oil pump 4 sends the pressurized fluid towards a hydraulic accumulator F and a hydraulic distributor 55 (Figure 1) which consists of a group of solenoid valves, electrically operated by a known computer (not shown). These solenoid valves close and open the fluid circuit towards the pressure chambers 15 and 16, respectively 39 and 40, thus enabling the gears to be engaged and disengaged and enabling the vehicle to reverse as well as to park.

The hydraulic accumulator F (Fig. 3) is located on and attached to the high-pressure hydraulic circuit between the oil pump 4 and the hydraulic distributor 55. It is designed to store the necessary quantity of fluid to engage the gears and it is also designed to absorb part of the mechanical shocks caused by gear shifting.

The hydraulic accumulator F consists of a cylindrical element 56 fitted with a threaded port s. The pressurized fluid goes through the threaded port s via a connecting pipe to the fluid storage chamber t. Inside the chamber t there is a sliding rod 57 fitted with a piston. The piston u reciprocates and exerts pressure on the fluid.

As shown in Fig. 13, the cylindrical element 56 is threaded on the outside to several threaded secondary elements 58 (Fig. 13) which form a tubing assembly. Inside this tubing assembly, along its axis, there is a sliding rod 57 fitted with circumferential passages v in which plates 59 are mounted (Fig. 13). These plates are pressed by coil springs 60 and 61, concentrically grouped in pairs and mounted independently on the end of each element in the tubing assembly. Finally, all groups of coil springs 60 and 61 form a force couple exerted on the piston u at the end of the sliding rod 57.

In what follows, the operation of the automatic gearbox is described, according to the present invention. When the engine starts, the ball hydraulic clutch 1 is set into motion and activates the oil pump 4 through the helical gears 2 and 3. When stepping on the gas pedal, the engine revolution speed increases and this leads to an increase in the revolution of the ball hydraulic clutch 1, which sends the pressurized fluid to the controller G (Figure 1). This controller is adjusted depending on the load capacity of the vehicle, obstructing its admission and discharge ports and thus leading to an increase of pressure in the ball clutch circuit 1.

At the same time, the clutch shaft 5 is set into rotary motion. When the computer (not shown) recognizes an equal number of revolutions in the PTO shaft 62 (Figure 1) and in the clutch shaft 5, it closes a solenoid valve 63 and, implicitly, the circuit of the pressurized fluid, leaving the PTO shaft 62 and the clutch shaft 5 engaged. Meanwhile, the oil pump 4 is engaged and aspirates the fluid through the intake valve (not shown) by means of a pipe (not shown) connected to the ports p and o of the hydraulic controller E and another pipe (not shown) in the cooling chamber 64. The fluid is then led through the output valve to the hydraulic accumulator F and the hydraulic distributor 55 and, implicitly, to the solenoid valves 65, 66,

67, 68, 69, 70, 71 , 72 and 73. When the engine exceeds a certain speed, the computer opens the solenoid valve 66, sends the pressurized fluid to the pressure chamber 16 which communicates with the gear rim 10 (Fig. 1). The solenoid valve 73 sends the pressurized fluid to the pressure chamber 40 which communicates with gear rim 36. The gear rims 10 and 36 engage the helical gears 7 and 22, creating a rigid coupling between them. This engagement enables the transmission of torque from the clutch shaft 5, through the intermediate shaft 12 to the output shaft 27 and thus, to the output coupling; as a result, the first gear is engaged, and the vehicle is set into motion. When the vehicle reaches a certain speed, the computer recognizes this and opens the solenoid valve 65 which sends the pressurized fluid to the pressure chamber 15, connected to the gear rim 9 and from there to its drum (not shown), which engages it with the helical gear 6.

Meanwhile, the computer closes the solenoid valve 66 and the pressure of the fluid in the drum (not shown) which communicates with the gear rim 10 is released to a pipe (not shown) leading to the cooling chamber 64. This disengages the first gear and engages the second gear (not shown). This process occurs instantaneously. Continuous pressure on the accelerator increases the speed of the vehicle and the process of engaging and disengaging the gears is repeated.

When the vehicle stops, be it on a horizontal surface or on sloped roads, the sensor mounted on the output shaft 27 recognizes that the vehicle has stopped and sends the information to the control computer (not shown), which engages the first and second gears simultaneously (not shown), thus blocking the gearbox. In order to restart the vehicle, the accelerator is pressed and the rotational speed of the clutch shaft 5 increases. Meanwhile, the control computer (not shown) is informed by a rotation sensor (not shown), the second gear is disengaged and the vehicle is able to start in first gear and then shift to other gears as they are actuated by the gas pedal or the brakes.

The present invention is preferably used in connection with the ball hydraulic clutch described in co-pending Application Serial No. , filed on October 5, 2015, or can be used in combination with any other clutch, conventional or otherwise.

Numerous structural and functional modifications and adaptions may be achieved, as those of ordinary skill in the art will readily appreciate, without departing from the spirit and scope of the invention.