CA1214812A - Driveline for a track-laying vehicle - Google Patents

Driveline for a track-laying vehicle

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Publication number
CA1214812A
CA1214812A CA000462937A CA462937A CA1214812A CA 1214812 A CA1214812 A CA 1214812A CA 000462937 A CA000462937 A CA 000462937A CA 462937 A CA462937 A CA 462937A CA 1214812 A CA1214812 A CA 1214812A
Authority
CA
Canada
Prior art keywords
drive
shaft
clutch
output
low
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA000462937A
Other languages
French (fr)
Inventor
Christopher J. Greenwood
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Leyland Vehicles Ltd
Original Assignee
Leyland Vehicles Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Leyland Vehicles Ltd filed Critical Leyland Vehicles Ltd
Priority to CA000462937A priority Critical patent/CA1214812A/en
Application granted granted Critical
Publication of CA1214812A publication Critical patent/CA1214812A/en
Expired legal-status Critical Current

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Abstract

ABSTRACT

DRIVE LINE FOR A TANK

A tank engine drive shaft (1) drives respective tank tack drive shafts (20, 30) by way of a continuously-variable ratio transmission variator (200), a transfer system (12, 13, 15) including coupling means (C1, C2, 16, 17), a cross shaft (18, 19) and respective summing epicyclic gears (7, 6). Steering of the tank is achieved by a steer variator (100) also driven (2, 3) by the engine, which outputs differential rotations as further inputs (82, 55) to the summing epicyclic gears (7, 6). The drive line operates in four distinct regimes: reverse, low I, low II and high, by means of an epicyclic gear brake (8), and clutches (H, C1 and C2).
The two parts (16, 17) of the coupling means are made to rotate in opposite directions by the annulus (15) of the epicyclics.
As the tank accelerates from rest in low I
regime, with brake B applied and clutch C1 applied but clutch H disengaged, the cross shaft (18, 19) decelerates. At a predetermined forward speed, the cross shaft is stationary and the change to low II is effected synchronously.
As the tank accelerates further forwards in low II regime, the cross shaft accelerates from rest in the opposite direction, with clutch C2 instead of clutch C1 engaged.

The use of the same transfer system for both parts of the low regime enables the use of a smaller variator (200) for an equivalent performance.

Description

~214812 DRIVE LINE FOR A TRACK-LAYING VEHI~LE X1551 This invention relates to a drive line for a ~rac~-laying vehicle such dS a military tank, and in particular to a drive iine employing speed shaft steering.

The invention consists in ~ drive line for a trac:~ iaying venicle 'navlng ,?eed shaC.
steer.ng, comprising two track drive sh~fts and a drive transmission whose output drives a shaft coupled to both track drive shafts by way of epicyclic gears having furt'ner inputs for steering, whereby the said shaft normally rotates while the vehicle is stationary, characterised in that the ~rive transmission has a continuously-variable ratio, and in that the drive transmission drives the shaft by way of a transfer system operable in at least low regime I and low regime II modes, the transfer system having a summing epicyclic gear arranged to sum the input and the output of the drive trans-mission and to provide a summed output, and coupling means for coupling the said summed ~14~3i2 output to the said shaft in either rotational sense to select either Low regime I or low regime II modes, low regime I being operable for ~ehicle velocities from rest to ~ cirst S predeter~ined velocity, and 'ow regime II being operabLe from the first to a second, higher, pre(letermined velocity.

I.~ the preferred orm of drive line, ~he - coupling means changes mode synchronously between low regime I and low regime II, the said shaft being stationary at the changeover point.
L~oreover, in the preferred embodiment the transfer system is further operable in a high regime mode in which the said summing epicyclic gear is locked and links the output of the drive transmission directly to the input of the coupling means, the input of the drive transmission being free to rotate relative to the transfer system.

In order that the invention may be better understood, two preferred embodiments will now be described with reference to the accompanying drawings, wherein:-~2~4812 Figure ] is a schematic diagr~m of a drive line Eor a trac'~-'3ying vehi~le ha~ ;pee~ snaft -,r,~ ing, FiJure 2 is ~ liagram showing .~ lrive 'ir.e .n accordance ~i.h ,~ st ~ lellt of -he invention and Fi,;.u-e 3 is .~ diagra~ , drive line In accordance with a second e.~Dodi~ent of ~he invention.
iO Figure 1 is a schematic illus~ration of a ;lrive line for a track-laying vehicle naving speed shaft steering and incorporating a continuously-variable ratio steering transmission, in accordance with the invention of our 3ritish patent application number 8322936. The drive line of Figure l is described in detail in our co-pending application, and no ~ore than 3 brief description will be yiven ~ere.

Drive I from the-tank engine is coupled both to a summing epicyclic gear J and to the input of a continuously-variable ratio transmission K, for ex~mple of the toroidal race rolling traction 12~48~L2 type. The olltpllt o~ ~he ~ontinuously-variable ratio steering transmission K is coupled both to a further inpllt of t'ne summing epicycLic gear ~, and also .hrough s~it~-lble gearing P to a urther summing epicyclic gear M whose output drives one of the tank ~racl~ ~rive shafts. The sut~ut of 'he summing epicyclic gear J is connecs~d via suitable ge~ring ~ ~o a further summing epicyclic gear L whose output drives ~he ,th~r _a.ik ~-~ack ~rive shaft. Each summing epicyclic gear L, `1 has a Eurther input driven i/ ~y the tank engine. The tank nas speed shaft steering, as opposed to null shaft steering, i.e. there is a rotating steering input to both epicyclics L, M when the tank and its track drive shafts are slationary.

Figure 2 shows the first embodiment of the ~rive line according to the invention. Tn this example, a continuously-variable ratio transmission 100 acts as a steer variator, and a similar continuously-variable ratio transmission 200 transmits driving power from the engine through a transfer system to a cross shaft 18, l9 and thence to respective tank track drive shafts 20, 30~

~214812 mhe steer variator 100 receives its drive input from the engine crankshaft 1 by way of gearing
2, 3. Geari~lg 3 is soupled to the input sha of the steer variator and also to the ~-1nnulus 53 of a simple epicyclic gear 3. The outp~. shaft 8 of the steer ~a.iator is connected at one end through gearing 81, 82 to the sun gear ~1 of a si,~ple epicyclic gear 7 whl-h supplies lrive to drive shaft 20. The other end of the output shaft 8 of the steer variator 100 is connected to the sun gear 51 of the simple epicyclic gear 5, of which the planet carrier 52 is connected to drive the sun gear 61 of simple epicyclic gear 6 by way of yearing 5~, 55.

As explained in our co-pending patent application referred to above, the simple epicyclic gear 5 causes the gears 54 and 81 to rotate in opposite rotational senses. The change of ratio introduced by the simple -0 epicyclic gear 5 is compensated for by suitably selecting the ratio of gearing 55 and 82; in this example, gearing 55 provides a ratio of - 2.86 and gearing 82 a ratio of + 1Ø Simple epicyclic gear 6 sums the drive from the cross lZ1481Z

shaft (at 18) and from the steer variator to provide a steered output on drive shaft 30.
Simple epicyclic gear '- sums the drive From the ~ross shaff (19) and .rom ~he steer varlator to provide a steered output on drive shaft 20.

The ~rive 'ine or the inver:~lon employs speed snaft steerlng, which means that _he sun gears ~1, .1 as ,iell as -he annuli ~3, '3 of simple epicyclic gears G, 7 respectively are made to rotate when the tank drive shafts 30, ,0 are stationary. Both the steering input (from gearing 55, 82) and the cross shaft 18, 19 are rotating when the tank is stationary. The invention lies particularly in the manner in which drive is supplied from the drive transmission 200 fo the track drive shafts 20, 30.

transfer system comprising an epicyclic gear arrangement 12, 13, 15 and brake B and a ~0 coupling means consisting of clutches Cl, C2 and gears 16, 17 allows the drive line to be operated in four distinct regimes for optimising its performance. The four drive regimes are:

l'Z148~2 reverse, low I, low II and high, corresponding respectively to tank speeds in reverse, low forwar~, medium forward and high forward.

Input shaft 10 of drive variator 200 is joined to the iun gear of simple epicyclic gear 12 of which 'he planet carrier may be held Dy a brake B and of which the annulus is connected to the planet ~,arrier of a second simple epicyclic gear 13. The output shaft 11 of the drive variator 200 is connected to the sun gear of the second simple epicyclic gear 13. The annulus 15 of the second simple epicyclic gear 13 provides an output in one rotational sense to gear 16, and in the opposite rotational sense to gear 17 of the coupling means. The coupling means employs clutches CL and C2 to engage to the cross shaft 18, 19 either gear 16 or gear 17 according to the reyime selected. A clutch H is operable, in two of the regimes, to lock the planet carrier to the annulus in the second simple epicyclic gear 13.

For the reverse regime, clutch H is engaged and clutch Cl is engaged. The input shaft 10 lZ~4~12 rotates freely relative to the transfer system since brake B is not applied. Output shaft 11 drives annulus 15 directly, which in turn drives the cross shaft through gear 16 and clutch Cl.

The high regime, for the highest forward speeds, is engaged by engaging cl~tch L~ and engaging clutch C2. It operates in tr.e same way as the reverse regime except that annulus 15 rotates gear 17 in the opposite rotational sense. For low I regime clutch H is not engaged, clutch Cl is engaged, and brake B is applied. Simple epicyclic gears 12, 13 then act to sum the inputs from input shaft 10 and output shaft 11 and supply a summed output through annulus 15 and gear 16 to clutch Cl. For low II regime, clutch C2 is engaged instead of clutch Cl, effectively reversing the drive to the cross shaft.

The cross shaft 18, 19 is stationary only at the changeover between low I regime and low II
regime, allowing this change to proceed synchronously. Thus, as the tank proceeds forwards from rest, it commences in low I regime g with the cross shaft being decelerated as the tank is accelerated. At a first æredetermine.1 forward speed, when the cross shaft is stationary, the change of regimes is effected.
Upon further acceleration of the tank, the cross shaft accelerates in the opposite direction until a second predeterminea forward speed is attained. The transfer system is preferably designed for synchronous change between low II
and high regimes, so that there is no relative movement between the plates of clutch H at the second predetermined forward speed. As the tank accelerates in high regime, the cross shaft accelerates from its second predetermined forward speed to its highest speed.

Figure 3 shows the second embodiment of the invention, which also operates in the four regimes. The only significant difference from the first embodiment is that the clutch H is replaced by clutches F and R, and a third simple epicyclic gear 14. This second drive line is more efficient than the first, since losses in the variator 200 are significantly reduced, but this is at the expense of the extra clutch and gearing 14.

lZ1481Z

For high regime, both clutches F and R are engaged, ~nd have the same effect as the clutch H of ~igure 2. For reverse regime only clutch R
is en~aged. For iow I and Iow LI regimes, the S brake 3 is applied, clutcn R .s disengaged and clutc:h F is engaged. .;part from these iifferences, the transfer system operates in .he same way as in the first emDodimerlt of Figure ~.

The principal advantage obtained by the invention, which is apparent ln both embodiments described above, is that the same transfer system is used for both parts of the low regime, low I and low II, enabling smaller variators to - be employed than would otherwise be the case for 1~ an equivalent performance.

A further advantage with the second embodiment arises from the provision of both clutches F and R. In slippery conditions, for example, it is sometimes desirable to start the tank from rest ~o with both clutches engaged; they then act effectively as a transmission brake, preventing the sudden acceleration of only one track.
Moreover, with both clutches F and R engaged, a neutral turn can be achievec`., with the tracks being propelled in opposite rotational senses while ~he tank is stationar~.

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A drive line for a track-laying vehicle having speed shaft steering, comprising two track drive shafts and a drive transmission whose output drives a shaft coupled to both track drive shafts by way of epicyclic gears having further inputs for steering, whereby the said shaft normally rotates while the vehicle is stationary, characterised in that the drive transmission has a continuously-variable ratio, and in that the drive transmission drives the shaft by way of a transfer system operable in at least low regime I and low regime II modes, the transfer system having a summing epicyclic gear arranged to sum the input and the output of the drive transmission and to provide a summed output, and coupling means for coupling the said summed output to the said shaft in either rotational sense to select either low regime I or low regime II, low regime I being operable for vehicle velocities from rest to a first predetermined velocity, and low regime II
being operable from the first to a second, higher, predetermined velocity.
2. A drive line in accordance with claim 1, wherein the changeover between low regime I and low regime II occurs synchronously, with the said shaft being substantially stationary at the changeover point.
3. A drive line in accordance with claim 1, wherein the transfer system comprises a clutch which, when engaged, locks the said summing epicyclic gear to effect a high regime whereby drive is transferred directly from the output of the drive transmission to the said coupling means.
4. A drive line in accordance with claim 3, wherein the change from low regime II to high regime is effected synchronously, there being substantially no relative movement between the plates of the said clutch at the changeover point.
5. A drive line in accordance with claim 1, wherein the said transfer system summing epicyclic gear comprises a first simple epicyclic gear having a sun gear driven by the input of the drive transmission, and a planet carrier connected to braking means, and a second simple epicyclic gear having a sun gear connected to the output of the drive transmission, a planet carrier connected to the annulus of the first simple epicyclic gear, and an annulus providing an output to the said coupling means.
6. A drive line in accordance with claim 5, comprising a clutch which, when engaged, couples the planet carrier to the annulus in the second simple epicyclic gear.
7. A drive line in accordance with claim 5, comprising a clutch arranged between the annulus of the second simple epicyclic gear and the output which drives the coupling means, and further comprising a third simple epicyclic gear having a sun gear connected to the drive transmission output, an annulus connected to the planet carrier of the second simple epicyclic gear, and a planet carrier coupled via a further clutch to the said output which provides drive to the coupling means.
8. A drive line in accordance with claim 1, 2 or 5, wherein the coupling means comprises input gears coupled in opposite rotational senses to the remainder of the transfer system, each gear arranged to drive the said shaft through a respective clutch.
9. A drive line in accordance with claim 1, 2 or 5, wherein the said shaft is a cross shaft driven by the coupling means and connected at either end to summing epicyclic gears each of which provides an output to a respective track drive shaft.
10. A tank incorporating a drive line in accordance with claim 1, 2 or 5.
CA000462937A 1984-09-12 1984-09-12 Driveline for a track-laying vehicle Expired CA1214812A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA000462937A CA1214812A (en) 1984-09-12 1984-09-12 Driveline for a track-laying vehicle

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA000462937A CA1214812A (en) 1984-09-12 1984-09-12 Driveline for a track-laying vehicle

Publications (1)

Publication Number Publication Date
CA1214812A true CA1214812A (en) 1986-12-02

Family

ID=4128697

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000462937A Expired CA1214812A (en) 1984-09-12 1984-09-12 Driveline for a track-laying vehicle

Country Status (1)

Country Link
CA (1) CA1214812A (en)

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