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TRANsuIssIoN MECHANIsu Filed Jan. 14, 1948` 1a sheets-sheet 17 Patented Nov. 7, 1950 TRANSMISSION MECHANISM Carl Einar Schon, Seattle, Wash., assignor to Paciiic Car and Foundry Company, Renton, Wash.
Application January 14, 1948, Serial No. 2,293
This invention relates to a multiple speed transmission of simple construction and operation and capable of increasing acceleration and improved maneuverability.
A further object of this invention is to provide a mechanism of the type in question in which the controls are of such a character that the vehicle in which the transmission is installed can be started at any selected speed or direction by a single simple motion of a control lever.
More specifically the present invention includes hydraulically controlled friction dry clutches for transferring from a drum type'flywheel power to an output shaft through preselected combinations of epicyclic gear trains compounded.
A further object of the invention is to provide in an assembly of the type described, a hydraulically operated dry clutch in which the pressure acts evenlyaround the entire area of the clutch discs, whereby peak emciency is obtained in operation and the possibility of hot spots eliminated.
A further object of the invention is to provide a clutch structure in which the clutch piston remains stationary relative to longitudinal motion, although rotating at the speed of its attached shaft.
A still further object is to provide a clutch assembly in which the cylinder of the hydraulic clutch mechanism is attached to and rotates with the shaft, and is capable of longitudinal movement through pressure in pressure chambers including in part a pair of steel alloy diaphragms, the clutch cylinder being attached to the clutch pressure plate for actuating the same.
Another and important feature of this invention is the provision of a pump mounted so as to be driven by the input shaft for maintaining constant pressures, and providing a iiuid supply suitable for control and operation of the clutches and an additional fluid supply for establlshing proper lubricating pressure, the uid supply for operation of the clutches being the same i'luid used in the lubrication of the mechanism.
Another object of the invention is to providev a hydraulic system for actuating the clutches in which centrifugal force is utilized for equalizing the pressures at both sides of the clutch piston to insure separation of the clutch elements during inoperative periods of the clutch.
Another object accomplished by this invention is the provision of balances for the torque reaction of the planetary gear trains by the use of external brakes two of which are of the double 21 Claims. (Cl. 74-761) wrapped type while the third is of the balance type.
Another object of the invention is to provide means for manual operation of the clutches upon failure of the hydraulic system.
In the drawings:
Figures l, 1b and lc constitute a longitudinal 'sectional view through the assembly:
Figure 2 is a transverse section on line 22 of Figure 1b;
Figure 3 is a transverse section on line 3 3 of Figure 1c;
Figure 4 is a section on line 4-4 of Figre 1;
Figure 5 is a partial elevation showing the end plate of the iilter cartridge chamber;
Figure 6 is a sectional view taken on line 6-6 of Figures 1b and 1;
Figure 7 is a sectional view on line 1--1 of Figure 3;
Figure 8 is a vertical sectional view on line 8-I of Figure 1a showing the pump structure for supplying pressure for operating the clutches and lubricating the device;
Figure 9 is a sectional view taken on line 9 9 of Figure la;
Figure 10 is a diagrammatic view showing the control layout for the present transmission in neutral position;
Figure 11 is a plan view of the control lever;
Figure 12 is a diagrammatic view showing the control system in first speed forward;
Figure 13 is a diagrammatic view of the control system in second speed forward;
Figure 14 is a diagrammatic view of the hydraulic control system shown in third speed forward;
Figure 15 is a diagrammatic View showing the control layout for fourth speed forward;
Figure 16 is a diagrammatic view of the conltrol system in fifth speed forward;
Figure 24 is an xploded view of the clutch actuating mechanii; and
Figure 25 is an" exploded view of the clutch plates associated with the structure of Figure 24.
Referring now to the assembly, power is supplied to the input shaft I through yoke 2 which is splined to the shaft I as indicated at 3 and retained in position by nut 4 threaded on the reduced shaft extremity 5 and locked in position by the cotter pin 6. The shaft I is provided with an annular flange 1 to which is secured the drum type flywheel 8 by rivets 9. The drum cylinder I is provided with a plurality of keys II forming splines, which may be secured by rivets I2 or these keys may be formed as an integral part of the drum assembly. Suitably spaced within the drum II'I of the flywheel are three clutches A-B and C each having a friction plate I4, I and I6, respectively, these plates having their outer peripheral edges notched to receive the keys II as indicated in dotted line at I1.
The input shaft I has its inner end axially bored to provide a uid chamber I8, the wall of this chamber at the inner end of the shaft being formed with an annular recess I9 defined at its inner end by the shoulder and receivesthe bearing raceway 2I in which are arranged the cylindrical bearings 22.
For mounting a series of clutch structures and planetary assemblies three concentric shafts are provided. The inner of the concentric shafts indicated by reference character 24 has its reduced end portion 25 provided with an outer bearing surface for arrangement and rotation within the confines of the roller bearing assembly 22. A thrust ring 23 prevents displacement of the bearing 22 and is interposed between adjacent shoulders on the input shaft I, and inner concentric shaft 24. The shaft 24 is formed with a central bore 26 throughout its entire length, the bore being open at the lend 26* in which there is provided a nipple26b, and is closed at its opposite end by the plug 21. This nipple 26b forms a closure for the cylindrical chamber 26c formed by the pipe 26d concentrically arranged within the bore 26 and spaced from the wall of the bore. A multiplicity of lateral ports are provided in the shaft communicatingwith the central bore cylindrical chamber 26 for the purpose of permitting the circulation of the lubricant and control fluid as will be hereinafter more fully described. Also it will be noted that the axial bore 26 is of greater diameter throughout that portion dened by the end to end limits of the clutch assembly. The forward end of the shaft adjacent the reduced bearing extremity 25 is enlarged at 28 to provide for the reception of the hub 29, of the clutch member 30, this clutch member 30 including the hub 29, the offset disc portion 30', and the annular flange or ring structure 3I which is formed at its periphery face with transverse teeth-32 (see Fig. 23). The ring structure 3| overlies the hub and the toothed periphery of the structure cooperates with the disc plates 33 and 34 shown in Figure 25. The disc plates 33 and 34 are formed with large central openings and equally spaced horizontal'arcuate toothed plates 35 extend about the annulus of the opening and are provided with internal teeth36 which mesh with the teeth 32 of the ring structure 3l. The arcuate plates 35 each form an equal segment of the annulus so that when the plates are assembled around the ring 3I these plates form a continuous tooth engaging structure about the periphery of annular flange 3|. The arcuate plates 35 are locked by rings 31 against transverse movement with respect to the toothed ring 3l. The structure of clutches A and B are substantially identical, the structure of these two clutches being comprehended by the clutch member 3| in Figure 23 and the clutch plate assembly of Figure 25. The clutch structure C is shown at Figure 24, in this clutch assembly the hub 29' of the member 32 being substantially elongated to extend within the partition wall of the main housing. The elongated hub 29a terminates in a spline structure 1I which forms a part of the first planetary assembly as hereinafter described. The elongated hub 299 thus forms the third or outer concentric shaft.
In the present design the three clutches are each furnishedwith a balanced pressure system. Each clutch includes the stationary piston 50, sealed and enclosed between the two diaphragms 56, and an outer ring 54, which provides two chambers, each of which are connected to their separate hydraulic pressure system. One chamberv is connected to the high pressure system which actuates the clutch and the other side is connected to the low pressure system. Both of the chambers are connected to the transmission lubricating system and thus as the pressure areas are identical, the specific gravity of the fluid in the two systems also are identical and any centrifugal affect upon the clutch pressure plate is eliminated regardless of the rotational speed. In the operation of the clutches the application of high pressure causes a shifting of the two concave plates together with their ring-like pistons 54, the movement of the pistons engaging the shiftable clutch plates 30 to cause the engagement of the clutch parts and the connection of the drive tothe associated assembly. As previously stated, the pressure in the two cylinders at each side of the xed members 50 is substantially balanced and the application of high pressure to the high pressure side unbalances the static condition and produces the essential actuating pressure. The ring-like member 54 whichv moves with the diaphragms 55 shifts in a horizontal plane or axially of the assembly, this movement being brought about by the action of the forces as well as due to the novel structure and prevents canting or unbalancing of the pressure plates.
Within the open wall chamber formed by the clutch member 30 there is arranged a piston 50, this piston being fixed on the hub 29 and in the form of a circular plate, the center portion of which is formed with an opening for seating about the hub 29 (see Figure 24). The peripheral edge portion 5I of the piston is provided with an annular channel 52 in which is arranged an O-ring 53. As stated the piston 50 is iixed against longitudinal movement but rotates with the hub 29 with the cylinder 54 the inner annularface 55 of which cooperates with the O-ring 53 to provide a liquid seal between the parts. The cylinder 54 is formed as a ring structure (see Figure 24) being connected to the hub 29 and rotating with this part but being free to slide axially of the assembly. At each side of the piston there is provided a light metal diaphragm 56 the outer peripheral edge of each of the diaphragms 56 being sealed into the annular outer faces of the longitudinally slidable cylinder 54 as at 51. The inner marginal edges 58 of the diaphragms 56 are sealed to the fixed piston 50 at its junction with the hub 29 of the friction plate 30. A seal