GB2179412A - A fluid-mechanical drive device - Google Patents

Abstract

A fluid mechanical drive device comprises an input drive shaft (2, 202, 302); an output drive shaft (3, 203, 303); a torque transfer system (4, 204, 304) mechanical connecting the input drive shaft to the output drive shaft; and a fluid drive (5, 205, 305) assembly connecting the torque transfer system to the output drive shaft. The fluid drive assembly comprises hydraulic pump means (6, 206, 306), pump-driving gear means (7, 207, 307) connecting the torque transfer system to the pump means (6, 206, 306), hydraulic motor means (9, 209, 309) connected to the pump means (6, 206, 306) and motor gear means (10, 210, 310) connecting the motor means (9, 209, 309) to the output drive shaft (3, 203, 303). The pump and motor are both variable in capacity and may be of the swash-plate type. <IMAGE>

Description

SPECIFICATION A fluid-mechanical drive device The present invention relates to a fluid-mechanical drive device which will accelerate a load from rest to a predetermined maximum speed. The device may also be used to accelerate a moving load to a higher predetermined speed.

Montalvo U.S. Patent No 4,049,095 describes a multiple speed transmission system, and more particularly a transmission system for driving the shaft of a winding or unwinding apparatus to keep the surface speed and web tension of a roll being wound or unwound substantially constant, while the roll diameter changes.

The present invention provides a transmission device for transferring rotational, or torque, power between an input drive shaft and an output drive shaft, in which the input drive shaft is driven by a prime mover, while the output drive shaft drives a load.

According to the present invention there is provided a fluid mechanical drive device comprising an input drive shaft; an output drive shaft; a torque transfer system mechanically connecting the input drive shaft to the output drive shaft; and a fluid drive assembly connecting the torque transfer system to the output drive shaft.

The power transmission device starts (load at rest) in a purely fluid mode, such as a hydraulic mode, as an instantaneous condition, and then progresses to a combined hydraulicmechanical condition, through a stepless increment, and finally to a fully mechanical predetermined maximum speed. The maximum speed is a function of design ratios, and input speed. The system may be operated continuously in any ratio of fluid mode to mechanical mode, or, at the limits, depending only upon the type of control used and the capacity of the device.

The control system may be manual, or may be automatic which is governed by speed, load or any number of other system variables or parameters. The control used for illustration is manual.

When the power transmission device, or drive device, according to the invention, is functioning completely in the fluid device, such as hydraulic drive mode, the input shaft provides the rotational power to drive the torque transfer system which operates the fluid drive assembly which, in turn, drives the output shaft.

When the power transmission device, or drive device is functioning completely in the mechanical drive mode, the input shaft provides the rotational power to drive the torque transfer system which in turn drives the output shaft.

Thus, when the drive device is operating initially, and the output drive shaft is stationary, the fluid drive assembly must be engaged in order to connect the torque transfer system to the output drive shaft. However, after the drive device has been operating for a time sufficient to bring the output drive shaft up to its desired rotational speed, the torque transfer system can connect the input drive shaft to the output drive shaft directly and mechanically. This is due to the fact that the functioning of the fluid drive assembly has been suspended or held in abeyance, so that the torque transmission of power can by-pass the fluid drive assembly as the rotary motion is transferred from the input drive shaft to the output drive shaft.

The torque transfer system comprises an input shaft drive gear attached to the input shaft; and linkage means connecting the input shaft drive gear with the output drive shaft; with the proviso that whenever the output shaft is motionless due to an initial stationary load holding the output shaft fixed, the linkage means will cause the pump gear means to actuate the hydraulic pump means to activate the hydraulic motor means, so that the output drive shaft will begin rotary movement driven only by the hydraulic motor means; and with the further proviso that whenever the output shaft has been driven to its maximum rotary movement by the hydraulic motor means, the motor means will cause the pump means to render motionless the pump gear means, so that the output drive shaft will continue rotary movement driven by the linkage means which is driven only by the input shaft drive gear.

Three embodiments of the device, in accordance with the invention, are based upon three different linkage means.

In the first embodiment the linkage means comprises an output shaft drive gear; at least one bevel transfer gear connecting the input shaft- drive gear with the output shaft drive gear; at least one cross shaft for supporting the or each one bevel transfer gear for rotary movement between the input shaft drive gear and the output shaft drive gear; a circumferential ring gear having the cross shaft positioned along the inside diameter thereof with the cross shaft attached to the inner wall of the ring gear; and which the arrangement of the bevel gear relative to the drive gears is such that the circumferential ring gear will rotate in the same direction as the input shaft drive gear, which direction is opposite to that of the output shaft drive gear.

The second embodiment of the invention has a linkage means that comprises a circumferential ring gear coaxial with the input shaft drive gear, the ring gear having an inner diameter greater than the outer diameter of the input shaft drive gear; at least one planet gear positioned between the input shaft drive gear and the ring gear, the or each planet gear being in simultaneous contact with both of the drive gear and the ring gear; an output drive disc fixedly mounted on the output drive shaft; at least one planet shaft connecting the planet gear to the output drive disc; and bearing means for the planet gear mounted between the planet gear and the planet shaft, so that the planet gear is capable of rotary movement around said planet shaft and within the circumferential ring gear.

The third embodimeijt of the invention employs a linkage means which comprises an output shaft drive gear attached to the output shaft; at least one input planet gear in contact with the input shaft drive gear; an input drive disc rotatably mounted on the input drive shaft; at least one ouput planet gear in contact with the output shaft drive gear; an output drive disc rotatably mounted on the output drive shaft; at least one planet shaft connecting together the input drive disc, the input planet gear, the output planet gear and the output drive disc; the planet shaft being rotatably connected at one end thereof to the input drive disc and being rotatably connected at the other end thereof to the output drive disc; and the planet shaft being fixedly attached to the input planet gear and being fixedly attached to the output planet gear.

The present invention has the advantages that it uses a hydraulic acceleration means through a stepless increment to achieve ultimately pure mechanical drive. There is a power savings by using a mechanical drive in conjunction with a hydraulic drive as opposed to a purely hydraulic drive.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Fig. 1 shows a perspective view of a first embodiment of the fluid mechanical drive device according to the present invention, Fig. 2 shows a perspective view of a second embodiment of the fluid mechanical drive device also according to the present invention, and Fig. 3 shows a perspective view of a third embodiment of the fluid mechanical drive device constructed in accordance with the pre sent invention.

Figs. 1, 2 and 3 respectively illustrate three embodiments of the present invention. Wherever possible, the same reference numerals are used to indicate those features and elements which are commori to these three different embodiments. However, in the second em bodiment shown in Fig. 2, each of the refer ence numerals that correspond to the identical feature shown in Fig. 1, will have a prefix of '200' for the feature shown in Fig. 2. Like wise, in Fig. 3, those reference numerals which refer to the same feature shown in Fig.

1, will be based upon the same reference numeral, but will have a prefix of '300'.

The fluid mechanical drive device is indi cated as 1 in Fig. 1, 201 in Fig. 2 and 301 in Fig. 3. This device comprises an input shaft 2 in Fig. 1, 202 in Fig. 2 and 302 in Fig. 3. The device further comprises an output shaft 3 in Fig. 1, 203 in Fig. 2, and 303 in Fig. 3. The device also comprises a torque transfer system which mechanically connects the input drive shaft 2 to the output drive shaft 3. This torque transfer system is generally indicated by the numeral 4 in Fig. 1, 2p4 in Fig. 2 and 304 in Fig. 3.

The device 1 further comprises a fluid drive assembly generally indicated ps 5 in Fig. 1, 205 in Fig. 2 and 305 in Fig. 3. This fluid drive assembly connects the torque transfer system 4 in Fig. 1 to the output shaft 3, connects the torque transfer system 204 in Fig. 2 to the output drive shaft 203, and connects the torque transfer system 304 in Fig. 3 to the output drive shaft 303.

The fluid drive assembly 5 comprises a hydraulic pump means 6, a pump gear means 7 which connects the torque transfer system 4 to the hydraulic pump means 6. The pump gear means 7 is connected by shaft means 8 to the hydraulic pump means. The fluid drive assembly further comprises a hydraulic motor means 9 which is connected to the hydraulic pump means 6. A motor gear means 10 is connected by shaft 11 to the hydraulic motor means. The motor gear means 10 connects the hydraulic motor means with the output drive shaft 3.

The corresponding features in Figs. 2 and 3 are indicated there in the drawing for the components of the fluid drive assembly.

The hydraulic pump means 6 of Fig. 1 further comprises a high pressure outlet port 12 and a low pressure suction port 13. The hydraulic motor means comprises a high pressure input port 14 and a low pressure exhaust port 15. A high pressure conduit indicated at 16, although not completely shown in the drawings for the sake of brevity, connects the high pressure outlet 12 of the hydraulic pump with the high pressure input port 14 of the hydraulic motor. A low pressure conduit 17, similarly illustrated, is attached between the low pressure suction port 13 of the hydraulic pump and the low pressure exhaust port 15 of the hydraulic motor 9.

An output gear means 18 is attached to the output shaft 3 and is in contact with the motor gear means 10. By contact, it is meant that the gear teeth on the outside surface of the output gear means and the motor gear means are meshed together such that rotational movement by one gear in one direction will rotate the other gear in the opposite di rection.

The hydraulic pump 6 further includes a first fluid flow control lever 19. The hydraulic mo tor 9 further includes a second fluid control lever 20.

The control lever 19 for the hydraulic pump is shown as being on the outside of the pump 6. The lever 19 controls a means within the pump for adjusting the fluid flow and the pressure inside the pump. This means inside the pump is indicated as 21 and could be pistons, or vanes. An example could be a swash plate type of piston pump. The second fluid control lever 20 for the hydraulic motor is located outside the hydraulic motor, and is connected to a means 22 inside the hydraulic motor for adjusting the fluid flow and the pressure inside the hydraulic motor.

Means 22 could be vanes or pistons, such as a swash plate type of piston pump.

The torque transfer system 4 includes an input shaft drive gear 23 attached to the input shaft 2. Linkage means connects the input shaft drive gear 23 with the output drive shaft 3. There is a proviso that whenever the output shaft 3 is motionless due to an initial stationary load (not shown) holding the output shaft 3 stationary, the linkage means will cause the pump gear means 7 to actuate the hydraulic pump means 6 to activate the hydraulic motor means 9, so that the output drive shaft 3 will begin rotary movement driven only by the hydraulic motor means 9.

There is the further proviso that whenever the output shaft 3 has been driven to its maximum rotary movement by the hydraulic motor means 9, this motor means 9 will cause the hydraulic pump means 6 to render motionless the pump gear means 7 so that the output drive shaft 3 will continue rotary movement driven by the linkage means which is in turn driven only by the input shaft drive gear 23.

Up to now, the various features shown and described for the first embodiment of the invention in Fig. 1 have had a corresponding identical feature shown and described for the second embodiment in Fig. 2, or for the third embodiment in Fig. 3. However, the linkage means shown and described for the first embodiment of the present invention in Fig. 1 is different from the linkage means shown and described for the second and third embodiments of the invention shown in Fig. 2 and Fig. 3 of the drawings.

Referring now to Fig. 1, the input drive shaft gear 23 is attached to the input drive shaft 2 by welding or in some other manner, such that rotation of shaft 2 causes rotation of gear 23 in the same direction and without any slippage between the gear 23 and the shaft 2.

The linkage means in Fig. 1 includes an output shaft drive gear 24 which is attached, such as by welding, to output shaft 3 in such a manner that rotation of gear 24 causes rotation of shaft 3 in the corresponding direction and without any slippage between gear 24 and shaft 3. There is at least one bevel transfer gear 25 connecting the input shaft drive gear 23 with the output shaft drive gear 24 and at east one cross shaft 26 for supporting the or each bevel transfer gear 25 for rotary movement between the input shaft drive gear 23 and the output shaft drive gear 24.

The linkage means of Fig. 1 also comprises a circumferential ring gear 27 having the cross shaft 26 positioned along the inside diameter of the ring gear 27 with the cross shaft 26 attached to the inner wall 28 of the circumferential ring gear 27. The arrangement of the bevel gear 25 relative to the drive gears 23 and 24 is such that the circumferential ring gear 27 will rotate in the same direction as the input drive shaft and the input shaft drive gear 23, which direction is opposite to the direction of rotation of the output shaft drive gear 24.

As shown in Fig. 1, there are in fact two bevel transfer gears supported on the cross shaft. The second bevel transfer gear 29 is supported on cross shaft 26 in such a manner that all four gears are in continuous contact with each other, as shown in Fig. 1. Thus, input shaft drive gear 23 simultaneously contacts bevel gears 25 and 29, which bevel gears simultaneously contact output shaft drive gear 24.

Bearing means are provided for each of the bevel transfer gears. Thus, bearing means 30 is provided for bevel transfer gear 25, while bearing means 31 is provided for gear 29.

Each bearing means is mounted between its respective bevel transfer gear and the cross shaft 26, so that each bevel transfer gear is capable of independent rotary movement around the cross shaft 26 and within the circumferential ring gear 27.

The circumferential ring gear 27 has gear teeth 32 on its outer periphery that mesh with the gear teeth 33 of the pump gear means 7.

The outer diamter of each of the bevel transfer gears 25 and 29 is smaller than the inside diameter of the circumferential ring gear 27, such that the bevel transfer gears do not contact the circumferential ring gear. The only contact between the bevel transfer gears is with the cross shaft 26 which cross shaft contacts the inner wall and is attached to the inner wall 28 of the circumferential ring gear 27.

Referring now to Fig. 2, the linkage means comprises a circumferential ring gear 40 coaxial with the input shaft drive gear 223. The circumferential ring gear 40 has an inner diameter greater than the outer diameter of the input shaft drive gear 223. There is at least one planet gear 41 positioned between the input shaft drive gear 223 and the circumferential ring gear 40. The planet gear 41 is in simultaneous contact with both of the drive gear and the circumferential ring gear. Simulta neous contact means that the gear teeth 42 on the outside surface of the planet gear 41 mesh with the gear teeth 43 on the outside surface of the gear 223 and simultaneously mesh with the gear teeth 44 on the inside surface of the circumferential ring gear 40.

A carrier means 45, which is an output drive disc, is fixedly mounted on the output drive shaft 203. Fixedly mounted means that this carrier, or spider, for example is welded to the output drive shaft 203.

There is at least one planet shaft 46 connecting the planet gear 41 to the spider, or carrier means, or output drive disc 45. Each planet shaft is fixedly attached to the output drive disc 45 at one end thereof.

Bearing means 47 for the planet gear 41 is mounted between the planet gear 41 and the planet shaft 46, so that the planet gear 41 is capable of rotary movement around the planet shaft 46 and within the circumferential ring gear 40. Thus, the planet gear may rotate around the planet shaft 46, but the planet shaft 46 is incapable of any rotary movement, since it is firmly and fixedly attached to the output drive disc 45.

As shown in Fig. 2, the linkage means comprises three planet gears, that is, gears 41, 48 and 49. These three planet gears are positioned between the input shaft drive gear 223 and the circumferential ring gear 40. The three planet gears are equidistantly spaced around the input shaft drive gear and within the circumferential ring gear, such that the three planet gears 41, 48 and 49 have the outside surface of each gear in simultaneous contact with the outside surface of the input shaft drive gear 223, and in simultaneous contact with the inside surface of the circumferential ring gear 40.

The circumferential ring gear 40, along its outer perimeter, has gear teeth 50 that mesh with the gear teeth 233 of the pump gear means 207, such that the circumferential ring gear 40 is a pump drive gear means.

Planet gear 48 has a corresponding planet shaft 51 connecting this planet gear 48 to the output drive disc 15. Bearing means 52 for the planet gear 48 is mounted between this planet gear 48 and its corresponding planet shaft 51, so that the planet gear is capable of rotary movement around the planet shaft and within the circumferential ring gear 40. However, the planet shaft 51 is fixedly attached to the output drive shaft 45 and is not capable of rotary movement.

Planet gear 49 has planet shaft 53 for connecting this planet gear 49 to the output drive disc 45. Bearing means 54 for the planet gear 49 is mounted between this planet gear and its corresponding planet shaft 53, so that the planet gear 49 is capable of rotary movement around the planet shaft 53 and within the circumferential ring gear 40. However, one end of planet shaft 53 is fixedly attached to the output drive disc 45 and therefore, planet shaft 53 is incapable of rotary movement.

In Fig. 2, the arrangement of the planet gears 41, 48 and 49 relative to the input shaft drive gear 223 is such that the circumferential ring gear 40 will rotate in the opposite direction to the direction of rotation of the input shaft drive gear 223, whenever the output drive shaft is being driven only by the hydraulic motor means 209, with the proviso that the output drive shaft 203 will rotate in the same direction as the input shaft drive gear 223. The input shaft drive gear rotates in the same direction as the input drive shaft 202.

The arrangement of the planet gears 41, 48 and 49 relative to the input shaft drive gear 223 is such that whenever the pump gear 207 renders motionless the circumferential ring gear 40, the planet gears will actuate the output drive disc 45 to rotate in the same direction as the input shaft drive gear 223, so that the input shaft 202 and the output shaft 203 rotate in the same direction.

Referring now to Fig. 3, the linkage means comprises an output shaft drive gear 60 attached to the output shaft 303 in such a manner, for example by welding, that the output shaft drive gear does not rotate or slip while in contact with the output shaft 303.

At least one input planet gear 61 is in contact with the input shaft drive gear 323, an input drive disc 62, or input carrier means, or spider, is rotatably mounted on the input drive shaft 302 and bearing means 63 are used to rotatably mount the input drive disc 62 on the input drive shaft 302.

At least one output planet gear 64 is in contact with the output shaft drive gear 60.

An output drive disc 65 is rotatably mounted on the output drive shaft 303 and bearing means 66 are used to rotatably mount the output drive disc 65 on the output drive shaft 303.

At least one planet shaft 67 is provided, connecting together the input drive disc 62, the input planet gear 61, the output planet gear 64 and the output drive disc 65. Planet shaft 67 is rotatably connected at one end thereof by bearing means 68 to the input drive disc 62 and is rotatably connected by bearing means 69 at the other end thereof to the output drive disc 65. The planet shaft 67 is fixedly attached to the input planet gear 61 and is simultaneously fixedly attached to the output planet gear 64. Thus, the planet shaft rotates and is driven by the input planet gear 61 so as to transmit the torque from input planet gear 61 to output planet gear 64.

Hence, there is no slippage between the planet shaft 67 and either one of the planet gears, input planet gear 61 or output planet gear 64.

As shown in Fig. 3, there are in fact three input planet gears, gear 61, as previously discussed, the second input planet gear 70 and the third input planet gear 75. Also there are three output planet gears, gear 64, as mentioned above, the second output planet gear 71, and the third output planet gear 76.

As shown in Fig. 3, there are three planet shafts. The first planet shaft 67 has been discussed above. The second planet shaft 72 connects the second input planet gear 70 with the second output planet gear 71. The third planet shaft 77 connects the third input planet gear 75 with the third output planet gear 76.

Each of the three planet shafts 67, 72 and 73 are equidistantly spaced around the surface of each of the input drive discs 62 and the output drive disc 65.

The second planet shaft 72 is rotatably connected at one end thereof by bearing means 73 to the input drive disc 62 and is rotatably connected at the other end thereof by bearing means 74 to the output drive disc 65.

The third planet shaft 77 is rotatably connected at one end thereof by bearing means 78 to the input drive disc 62; and is rotatably connected at the other end thereof by bearing means 79 to the output drive disc 65.

A pump drive circumferential ring gear 80 is provided which is coaxial with the output shaft 303, and the pump drive circumferential ring gear has an inside diameter greater than the outside diameter of the output shaft 303.

Thus, the pump drive ring gear does not contact the output shaft 303. The pump drive circumferential ring gear 80 has gear teeth 81 along the outside surface thereof that mesh with the gear teeth 333 of the pump gear 307. A cylindrical tube means 82 fastens the pump drive circumferential ring gear 80 to the output drive disc 65.

The first embodiment for the fluid mechanical drive device 1 of the present invention, illustrated in Fig. 1, operates as follows.

The prime mover, such as a motor or an engine, (which is not shown) is directly connected to the input shaft 2 which is integral with the input drive gear 23. The input drive gear is in mesh with the two transfer gears 25 and 29 which are carried by bearings 30 and 31 mounted on cross shaft 26 which is integral with ring gear 27.

The ring gear 27 has external teeth 32 which mesh with teeth 33 of pump gear 7.

The transfer gears 25 and 29 are also in mesh with output bevel gear 24. The output bevel gear 24 is integral with output shaft 3.

The output gear 18 is also integral with the output shaft 3; and output gear 18 is in mesh with motor gear 10.

The pump 6 and the motor 9 are both of the variable displacement type.

The pressure port 12 of pump 6 is connected to the inlet port 14 of motor 9; and the exhaust port 15 of motor 9 is connection to suction port 13 of pump 6. A pressure surge compensating device (not shown) may be used within this closed-loop circuit.

An examination of the device will reveal that the direction of rotation of the output shaft is the reverse of the direction of rotation of the input shaft 2. This first embodiment has the advantage that if the device is properly mounted, then this has a convenient torque cancelling effect.

For the first embodiment of the device 1, in Fig. 1, the initial conditions are as follows: (a) the prime mover is operating; (b) the pump control lever 19 and the motor control lever 20 are each set at the zero displacement position; and (c) the load and output shaft 3 is at rest.

To begin motion, the control lever 20 for motor 9 is set in the full displacement position, remembering the proper rotational direction. Next the control lever 19 for the pump 6 is shifted into the full displacement position, again with the proper rotation in mind. This causes the output shaft 3 to begin rotating.

Instantaneously at the very start of this rotational motion, the pump 6 is driving the motor 9, and the device 1 is completely hydraulic actuated. As soon as rotational motion of the output shaft 3 begins, the device 1 becomes partially mechanically actuated and is also simultaneously hydraulically actuated.

From its initial position at rest to the onset of motion the following occurs in the device: The initially stationary load is holding the output shaft 3 fixed and stationary. The prime mover drives the input shaft 2 and drives the main or input drive gear 23, which in turn drive transfer gears 25 and 29. Transfer gears 25 and 29 are in mesh with output bevel gear 24 which is stationary at the start-up, because the output shaft 3 is at rest.

As shown in Fig. 1, if the input shaft 2 is assumed to be rotating in the clockwise direction, then this condition will cause the transfer gears to rotate as shown in Fig. 1 and to move translationally about the stationary output bevel gear 24. This will cause gears 25 and 29 to drive the ring gear 27 by means of the cross shaft 26. Thus the ring gear 27 will rotate clockwise as shown in Fig. 1.

The now rotating ring gear 27 drives pump gear 7 which drives the pump 6. The pump 6 forces hydraulic fluid through conduit 16 to motor 9 thus driving the motor, which drives motor gear 10.

Motor gear 10 is in mesh with output gear 18. When motor gear 10 begins rotary motion, the output gear 18 also begins motion which initiates motion of the output shaft 3 and hence the coupled load (not shown). Instantaneously at the beginning of this motion, the system is in a purely hydraulic mode.

To change ratio toward the minimum hydraulic, and purely mechanical mode, the following is done.

Control lever 20 on motor 9 is moved toward the zero displacement position. As this is being done, the motor 9 is increasing speed, as is the output shaft. This is a result of reduced displacement capacity. Simultaneously, pump 6 is slowing down, because of increased resistance within motor 9. At zero displacement of the motor 9, the motor will "freewheel"; and pump 6 will be locked, because of the "no flow" condition for fluid flow through motor 9. With the pump thus locked, ring gear 27 is also locked.

At this point, the device 1 is in a purely mechanical mode and the power flow is as follows.

Input shaft 2, which is driven by the prime mover to rotate in the clockwise direction as shown in Fig. 1, drives input gear 23 which drives the now locationally fixed transfer gears 25 and 29 to rotate as shown in Fig. 1. The transfer gears 25 and 29 drive the output bevel gear 24, which drives the output shaft 3 to rotate in the counterclockwise direction as shown in Fig. 1, and the coupled load (not shown).

The device 1 is not operating at maximum speed in a purely mechanical (non-hydraulic) mode.

The second embodiment of the fluid mechanical drive device 201 of the present invention, illustrated in Fig. 2, operates as follows.

The input shaft 202 and the drive 223 are integrally connected and are driven directly by the prime mover (not shown).

The planet gears 41, 48 and 49 are in mesh with drive gear 223 and are carried by bearings 47, 52 and 54 respectively, mounted on planet shafts 46, 51 and 53 respectively, which shafts are integral with carrier disc 45.

(This, of course, is only one of several embodiments for the mounting of the planet gears.) The ring gear 40 has internal teeth 44 in mesh with planet gears 41, 48 and 49, thus forming a full planetary set. The ring gear 40 is shown with external teeth 50.

The external tooth side of ring gear 40 drives the pump gear 207.

The spider disc 45 is also integrally connected to the output shaft 203 which is integrally fixed to output gear 218. Output gear 218 is in mesh with motor gear 210.

The pressure port 212 of pump 206 is connected to inlet port 204 of motor 209 and the exhaust port 215 of the motor 209 is connected to suction port 213 of pump 206.

A surge pressure compensating means usually is placed in this closed loop' circuit.

Both pump 206 and motor 209 are of the variable displacement type, and are controlled manually as shown (in the drawings) by control levers 219 and 220, respectively. It is possible to use automatic controls under actual operating conditions.

For the second embodiment of the device 201, in Fig. 2, the initial conditions are as follows: (a) the prime mover is operating; (b) the pump control levers 219 and the motor control lever 220 are each set at the zero displacement position; and (c) the load and output shaft 203 is at rest.

To begin motion, the motor control lever 220 is placed in the full displacement position, taking into account the direction of rotation of shaft 203 which must be the same as that of input shaft 202.

Then the pump control lever 219 is placed in full displacement position, also taking shaft rotation into account.

The drive is now in the minimum speed mode with the maximum ratio of fully hydraulic mode. The load which is coupled to the output shaft 203 is now in rotary motion; and the fully hydraulic mode of torque power transmission occurs instantaneously.

The path of power flow from the prime mover (not shown) to the output shaft is as follows.

The input shaft 202 is driven by the prime mover in a clockwise rotation and the shaft 202 drives gear 223 with which it is integrally attached.

At the initial start-up point, only the spider disc 45 is now fixed by the stationary output shaft 203. The planet shafts 46, 51 and 53 which are integrally connected with the spider 45 are also stationary as an instantaneous condition.

The gear 223 drives planet gears 41, 48 and 49 hich drive ring gear 40 counterclockwise which, in turn, drives pump gear 207. The pump gear 207 drives the pump 206 which develops hydraulic pressure and delivers this pressure to the motor 209.

The motor 209 now begins to rotate driving motor gear 210 counterclockwise which drives output gear 218 clockwise and in turn drives output shaft 203 clockwise.

The drive is now in its maximum ratio, and slowest output condition.

In order to change the ratio of the drive, and hence to change the output speed, the control lever 220 of the motor 209 is moved toward the zero displacement position. This causes the motor speed to increase because of decreased displacement capacity. Simultaneously, the pump 206 begins to slow down because of increased fluid flow restriction caused by the reduced displacement capacity of the motor 209.

The result of this situation is that the motor 209 is increasing the speed of output shaft 203 while the pump 206 is slowing the speed of ring gear 40.

When motor 206 has reached zero displacement, with control lever 219 held at zero angle, the motor 209 may freewheel.

The pump 206 is locked, because it remains in its full displacement mode, against a "noflow" condition for fluid through the motor 209.

The device 201 is now operating fully mechanically and the power flow is as follows.

The prime mover drives input shaft 202 clockwise as shown in Fig. 2, which drives gear 223. Gear 223 drives planet gears 41, 48 and 49. Planet gears, being driven by gear 223 must travel around in a translational circular motion, inside ring gear 40.

The locational movement of planet gears 41, 48 and 49 rotates spider 45 through planet shafts 46, 51 and 53 respectively.

Since the spider 45 and the output shaft 203 are integrally connected, the output shaft 203 is not operating in a purely mechanical drive mode from the prime mover.

As in the previously discussed embodiment, the device 201 will function without a variable displacement pump, but will always be engaged in the driving mode. The zero displacement position of the pump 206 provides a neutral (no drive) mode for the device.

To reverse the device, the motor 209 would be placed in the full displacement starting position. This would slow the drive to its minimum RPM. Then the pump lever 219 would be moved to full reverse position.

If the two above features are to be incorporated in the device 201, then it will be necessary to have a variable displacement pump.

The third embodiment of the fluid mechanical drive device 301 of the present invention is illustrated in Fig. 3, and operates as follows.

A prime mover (not shown) is connected to the input drive shaft 302 which is integrally connected to the input drive gear 323. The input drive shaft is carried by a bearing 63 which is mounted in the spider, or carrier, 62 on the input side.

The spider comprises input drive disc or flat plate 62 plus output drive disc or flat plate 65, as shown. It is possible to have three or more discs in practice, with one or more located centrally. These plates contain bearings which carry the planet shafts 67, 72 and 77, the input drive shaft 302, and the output drive shaft 303.

The pump gear 81 is integrally fixed to the end of the tube 82 which is fixed to drive disc 65 so one rotation of the disc 65 produces one rotation of the pump drive gear 80.

The pump drive gear 80 drives the pump gear 307.

The input shaft 302 is keyed, welded or otherwise solidly coupled to input drive gear 323. Output drive gear 60 is coupled to output drive shaft 303, and output shaft 303 is coupled to output shaft gear 318 in the same way.

The output shaft gear 318 is in mesh with motor gear 310. The motor gear 310 drives the output shaft gear 318 and the output shaft 303 during part of the operating cycle.

The entire assembled device can be housed in a suitable container which carries the internal components on bearings between the container and the main shaft, and provides flange mountings for the hydraulic pump and the hy draulic motor.

The motor 309 is a hydraulic motor of the variable displacement type. It may be of any suitable construction such as a piston for example. For example, the swash plate piston type is suitable for use.

The pump 306 is also of variable displacement. In the description it may be assumed that the pump is set at the maximum displacement at the start-up time and is kept there.

The pressure port 312 of pump 306 is connected to the inlet port 314 on motor 309.

The exhaust port 315 on motor 309 is connected to the suction port 313 on pump 306.

A surge pressure compensating device is usually used in this closed loop circuit.

For the third embodiment of the device 301 in Fig. 3, the initial conditions are as follows: (a) the load and output shaft 303 are at rest and stationary (b) the pump control levers 319 and the motor control lever 320 are each set at zero displacement position; and (c) the prime mover (i.e. motor or engine) is running.

To begin, the motor 309 control lever 320 is placed in full displacement position for the direction of selected rotation, in which the prime mover is turning and as shown in Fig.

3, the input shaft 302 is rotating clockwise.

Based upon the selected direction of rotation, the pump 306 control lever 319 is moved to the full displacement position. As this second move is being made, motion of the device begins as follows.

The prime mover will drive the input shaft 302 which will rotate clockwise in Fig. 3, rotating the input drive gear 323. The initial starting condition is that output shaft 303 is locked and rendered immovable by the stationary load (not shown). Because of this, the input gear 323 causes the input planet gears 61, 70 and 75 to rotate which transfer motion through planet shafts 67, 72 and 77 to output planet gears 64, 71 and 76, respectively.

Because of the initially stationary condition of output shaft 303 and consequently of the output drive gear 60, the output planet gears being driven will travel around the output drive gear 60 in the counterclockwise direction.

This will drive the discs 62 and 65 causing them to rotate in the counterclockwise direction.

Since the pump drive gear 80 is mechani cally integrally attached to cylinder connector 82 and to disc 65, this gear 80 will rotate at the same spped at the spider 65.

The pump drive gear 80 drives the pump gear 307 which causes the pump 306 to function.

The pump 306 which is now in motion pro duces hydraulic pressure which is transmitted through conduit 316 to the motor 309 which is not in the full displacement mode, and re sponds by driving the motor gear 310 coun terclockwise. Gear 310 drives the output shaft gear 318 clockwise and the output shaft 303 clockwise. Hence the load is driven at its highest ratio, and slowest speed, by the torque drive of this fully hydraulic, or instantaneous initial power transmission means. At this point in time, there is no mechanical torque drive, and only hydraulic power drive.

To begin to change the ratio of mechanical versus hydraulic drive, the motor 309 control lever 320 is moved toward the minimum displacement position. As this is done, several things begin to occur simultaneously. The motor 309, because of decreased displacement begins to accelerate. The increased restriction caused by the reduced displacement of motor 309 begins to slow down the pump 306. The increased rotational speed of motor 309 is transmitted by motor gear 310 to output shaft gear 318 and hence to output shaft 303. Motor gear 310 rotates counterclockwise causing gear 318 and output shaft 303 to rotate clockwise, or in the same direction as input shaft 302.

The decreasing rotational speed of the pump 306 is transmitted through pump gear 307 to pump drive gear 80 which begins to brake, or to slow down the rotational speed of disc spider 65.

The ultimate result of this change is that with control lever 320 of the motor 309 in the zero displacement position, the motor may freewheel. The motor 309 is allowing no fluid flow therethrough, thus locking the pump 306 which remains in the full displacement position, and consequently locks spider disc carrier 65.

With the pump 306 locked and with the disc 65 locked, and with the motor 309 freewheeling, the resultant path of motion will be as follows: The prime mover causes the input shaft 302 to rotate clockwise which drives the gear 323. Input gear 3323 drives the input planet gears 61, 70 and 75 counterclockwise which transmit this rotation torque through the planet shafts 67, 72 or 77 respectively which are carried in bearings 69, 74 or 79, by the now stationary spider disc 65.

Planet shafts 67, 72 and 77 transmit counterclockwise motion to the output planet gears 64, 71 and 76 which in turn transmit clockwise motion to the output drive gear 60.

The output drive gear 60 is fixedly attached to output shaft 303.

Output shaft 303 is carried in spider 65 by a bearing 66, and transmits clockwise torque rotational power to the load to which it is coupled.

The device will function without a variable displacement pump, but then will always be engaged in a driving mode. The zero displacement position of pump 306 provides a neutral, no drive, mode for the system.

To reverse the device, the motor 309 is to be placed in the full starting position, which will slow the drive to its minimum RPM. Then the pump lever 319 must be moved to the full reverse position.

If both of these two above positions are to be used, then a variable displacement pump is to be utilised.

As used in the above description of the invention, the terminology "linkage means" refers to a drive train means that, in part, links together the imput with the output elements of the device.

A specific example of the hydraulic pump, which may be used, is the "Vickers PVB-5" variable displacement swash plate piston pump. However, other known variable displacement pumps may be utilised.

A specific example of the hydraulic motor, which may be used, is the "Vickers MVB-5" variable displacement swash plate piston motor. However other known variable displacement motors may be utilised.

Wherever possible, the component parts of the device are made from hard, strong and durable material, such as metal, for example, steel or brass.

Claims (14)

1. A fluid mechanical drive device comprising an input drive shaft; an output drive shaft; a torque transfer system mechanically connecting said input drive shaft to said output drive shaft; and a fluid drive assembly connecting said torque transfer system to said output drive shaft.

2. A drive device according to Claim 1, wherein said fluid drive assembly comprises hydraulic pump means; pump gear means connecting said torque transfer system to said pump means; hydraulic motor means connected to said pump means; and motor gear means connecting said motor means with said output drive shaft.

3. A drive device according to Claim 2, wherein said hydraulic pump means further comprises a high pressure, outlet port and a low pressure, suction port; said hydraulic motor means further comprising a high pressure input port and a low pressure exhaust port; and wherein said fluid drive assembly further comprises a high pressure conduit means attached between said outlet port of said pump and said input port of said motor; a low pressure conduit means attached between said suction port of said pump and said exhaust port of said motor; and an output gear means attached to said output shaft and in contact with said motor gear means.

4. A drive device according to any one of Claims 1 to 3, wherein said fluid drive assembly further comprises a first fluid control lever for said hydraulic pump; and a second fluid control lever for said hydraulic motor.

5. A drive device according to Claim 2, wherein said torque transfer system comprises an input shaft drive gear attached to said in put shaft; linkage means connecting said input shaft drive gear with said output drive shaft; with the proviso that whenever said output shaft is motionless due to an initial stationary load holding said output shaft fixed, said linkage means will cause said pump gear means to actuate said hydraulic pump means to activate said hydraulic motor means, so that said output drive shaft will begin rotary movement driven only by said hydraulic motor means; and with the further proviso that whenever said output shaft has been driven to its maximum rotary movement by said hydraulic motor means, said motor means will cause said pump means to render motionless said pump gear means, so that said output drive shaft will continue rotary movement driven by the linkage means which is driven only by said input shaft drive gear.

6. A drive device according to Claim 5, wherein said linkage means comprises an output shaft drive gear; at least one bevel transfer gear connecting said input shaft drive gear with said output shaft drive gear; a cross shaft for supporting said at least one bevel transfer gear for rotary movement between said input shaft drive gear and said output shaft drive gear; a circumferential ring gear having said cross shaft positioned along the inside diameter thereof with said cross shaft attached to the inner wall of said ring gear; and wherein the arrangement of said bevel gear relative to said drive gears is such that said circumferential ring gear will rotate in the same direction as said input shaft drive gear, which direction is opposite to that of said output shaft drive gear.

7. A drive device according to Claim 6, wherein two bevel transfer gears are supported on said cross shaft, bearing means for each of said bevel transfer gears are mounted between each bevel transfer gear and said cross shaft, so that each bevel transfer gear is capable of independent rotary movement around said cross shaft and within said circumferential ring gear; and wherein said circumferential ring gear has gear teeth along its outer perimeter that mesh with the pump gear means.

8. A drive device according to Claim 6 or Claim 7, wherein the outer diameter of each of said bevel transfer gears is smaller than the inside diameter of said circumferential ring gear, such that said bevel transfer gears do not contact said circumferential ring gear.

9. A drive device according to Claim 5, wherein said linkage means comprises a circumferential ring gear coaxial with said input shaft drive gear, said ring gear having an inner diameter greater than the outer diameter of said input shaft drive gear; at least one planet gear positioned between said input shaft drive gear and said ring gear, said planet gear in simultaneous contact with both of said drive gear and said ring gear; an output drive disc fixedly mounted on said output drive shaft; at least one planet shaft connecting said planet gear to said output drive disc; and bearing means for said planet gear mounted between said planet gear and said planet shaft, so that said planet gear is capable of rotary movement around said planet shaft and within said circumferential ring gear.

10. A drive device according to Claim 9, wherein said linkage means comprises three planet gears positioned between said input shaft drive gear and said ring gear, said three planet gears being equidistantly spaced around said input shaft drive gear; said circumferential ring gear having gear teeth along its outer perimeter that mesh with the pump gear means, such that said circumferential ring gear is a pump drive gear means; the arrangement of said planet gears relative to said input shaft drive gear being such that said circumferential ring gear will rotate in the opposite direction as said input shaft drive gear whenever said output drive shaft is driven only by said hydraulic motor means, with the proviso that said output drive shaft will rotate in the same direction as said input shaft drive gear; and the arrangement of said planet gears relative to said input shaft drive gear is such that whenever said pump gear renders said circumferential ring gear motionless, said planet gears will actuate said output drive disc to rotate in the same direction as said input shaft drive gear, so that said input shaft and said output shaft rotate in the same direction.

11. A drive device according to Claim 5, wherein said linkage means comprises an output shaft drive gear attached to said output shaft; at least one input planet gear in contact with said input shaft drive gear; an input drive disc rotatably mounted on said input drive shaft; at least one output planet gear in contact with said output shaft drive gear; an output drive disc rotatably mounted on said output drive shaft; at least one planet shaft connecting together said input drive disc, said input planet gear, said output planet gear and said output drive disc; said planet shaft being rotatably connected at one end thereof to said input drive disc and being rotatably connected at the other end thereof to said output drive disc; and said planet shaft being fixedly attached to said input planet gear and being fixedly attached to said output planet gear.

12. A drive device according to Claim 11, comprising three input planet gears; three output planet gears; three planet shafts, with each one of said planet shafts connecting an input planet gear to its respective output planet gear; and said planet shafts being equidistantly spaced around the surface of each of said input drive disc and said output drive disc.

13. A drive device according to Claim 11, further comprising a pump drive circumferential ring gear which is coaxial with said output shaft, said pump drive ring gear having an inside diameter greater than the outside diameter of said output shaft; said pump drive circumferential ring gear having gear teeth along its outside surface that mesh with the gear teeth of said pump gear; and cylindrical tube means for fastening said pump drive circumferential ring gear to said output drive disc.

14. A fluid mechanical drive device, substantially as hereinbefore described and with reference to Figure 1, Figure 2 or Figure 3 of the accompanying drawings.