FR2575118A1 - CONTROL DEVICE FOR A MOTOR VEHICLE, IN PARTICULAR FOR A FORKLIFT - Google Patents

Abstract

A. CONTROL DEVICE FOR A MOTOR VEHICLE, ESPECIALLY FOR A LIFT TRUCK. B. DEVICE CHARACTERIZED IN THAT THE BRAKE ACTUATOR 25 IS IN OPERATIONAL LINK WITH THE ADJUSTING DEVICE 26 OF THE CONTROL PRESSURE ADJUSTING VALVE 14. C. THE INVENTION RELATES TO BRAKE CONTROL DEVICES FOR MOTOR VEHICLES.

Description

Control device for a motor vehicle, in particular

for a forklift. "-

  The invention relates to a control device

  for a motor vehicle, in particular for a forklift (forklift) with a primary energy source and a continuously adjustable transmission ensuring

  preferably a forced transmission, in particular a transmission

  hydraulic mission, the adjuster of which is connected to a regulating piston whose position is determined by a

  control pressure whose size can be adjusted voluntarily

  by means of a pressure regulating valve

  and with a brake urged by an energy accumulator.

  preferably a spring, and likely to be

  blocked by means of a pressure transmitted by a channel

  brake pressure and controlled by a control

the freino

  An order for the hydraulic transmission

  that of a forklift drive system is known and has performed very well in practice, command

  in which the accelerator pedal is directly re-

  mechanically connected with the control member of the trans-

  mission, while there is provided an additional pedal through the actuation of which the hydraulic transmission adjustment linkage is first brought to the position corresponding to the neutral position of the 2. - transmission and then when operating this other pedal with greater mechanical effort,

  a mechanical brake is actuated (DE-PS 18 17 849). Linen-

  It is a good idea that this device requires a relatively high complexity of mechanical linkages, and for brakes provided for significant braking efforts.

  tants, requires significant effort on the pedal.

  There is furthermore known a control device for a vehicle controlled at differential speed, which

  has brakes kept tight by the action of a

  fate and likely to be unlocked by a hydrau-

  then a brake pedal is again

  for the braking process and the hydraulic transmission

  that the drive of the vehicle being able to be controlled by means of a control pressure adjustable to

  will. In this system two different pressure valves

  are connected to the brake pedal, however, when this brake pedal is actuated, the control pressure for the hydraulic transmission is

  first reduced by being finely adjustable and the trans-

  The mission is thus adjusted to the zero position, while the braking pressure is then reduced and thus the brakes are made to be controlled under the action of the springs (DE-OS 32 41 793). This device, with the two differential pressure valves, requires

  a relatively high expense in control organs.

  The problem posed to the invention is to create

  a control device in which, during the actuation

  the brake pedal (brake actuating member) the hydraulic transmission adjustment position is first modified in the direction of stopping the output shaft of this transmission, and is then that the braking is effected by means of the mechanical friction brake, the control device then comprising

  that a reduced expenditure in control organs.

3.-

  This problem is resolved in accordance with the

  in that the actuating member of the brake is in operational connection with the adjustment member of the

  control pressure control valve.

  Thanks to this functional link, the

  first part, starting from the normal position correspon-

  with the brake released, the actuating stroke of the brake operating member is associated, up to

  stopping the output shaft of the trans-

  mission, to a process of adjusting the check valve

  setting of the control pressure, while the

  Each of the stroke of the brake operating member is associated with a process of actuating the brake pressure lowering valve. Thanks to the operational connection, a change in the control pressure beyond the value corresponding to the stopping of the output shaft, is then only possible when the brake pressure is brought to the total value corresponding to the brake

completely unlocked.

  In the case of the forks with aforementioned forks with a mechanical connection between the accelerator pedal and the hydraulic transmission control member, a connection with the control member of the internal combustion engine (DE-PS) is also already known. 15 26 528). According to an advantageous form of the invention, a similar basic concept is applied to the device according to the invention in that the actuating member of the control pressure control valve is in operative connection with

  the actuating member of the regulating valve.

  In the case of a control device according to the invention, the control pressure line transmitting the control pressure for the adjustment of the transmission is advantageously connected with

  with the brake pressure line via

  valve at will, at least 4.- in the neutral position of this valve associated with the

  neutral position of the transmission. In the case of a

  Positive control in which, a pressure of a level

  predetermined position prevails in the control line

  weaving the transmission adjusting member, when this transmission is set to neutral position, it is

  advantageously provided in the neutral position of the trans-

  a link via a valve, preferably via the vehicle direction-select valve, between the control pressure line leading to the transmission and

  the brake pressure line.

  It is also particularly advantageous for the control pressure control valve to be fed on the inlet side by the pressure which is accumulated.

  upstream of a choke point in the recirculation circuit

  flow of a constant pump entralnée by the primary energy source (this is known per se: DE-OS 31 43 539) the pipe downstream of this throttling point being previously subjected to a determined pressure, while this line are connected, both the control pressure control valve and other

  components of the entire control device, and in particular

  the brake pressure line, preferably

  via a choke point.

  In accordance with the present invention,

  It is important that the control pressure for the trans-

  mission is determined from a control pressure control valve in the form of a pressure relief valve, and that

  the actuation of the brake pedal is controlled mechanically

  only at a reduced output pressure, so that the transmission is set in the direction of

  the output shaft and only then the pressure

  brake is lowered and thus the brake is applied.

  - Acet effect, it is provided on the regulating valve of the

  command pressure, ie an action of the

  brake actuation on the single actuating member of this control pressure regulating valve, or there is preferably provided an actuator actuated from the accelerator pedal and it is

  provided a second actuating member influencing the res-

  fate acting on the opposite side to the first

  tioning. It is known from DE-OS 34 27 422

  to make reversing organs and influential organs

  placing the control pressure in the form of

  nants. In correlation with the present invention,

  particularly advantageous constructive

  be considered using such drawers.

  According to one of the features of the invention

  the direction selector valve of the vehicle is designed as a rotating spool valve, whose rotating spool body is provided with a lever-shaped part against which

  a support cup for the spring of the check valve

  of the control pressure, whose axis of

  is arranged, at least approximately, radially

  relative to the axis of the rotary drawer.

  The present invention is explained in more detail with the aid of the accompanying drawings, in which: FIG. 1 is a circuit diagram of a control device according to the invention;

  - Figures 2, 3 and 4 are different

  from one and the same control unit.

  The control device is disposed in the casing 1. The constant displacement pump 2 sucks, via a pipe 3 from the tank 4, and discharges through a pipe 5 and the filter 6 to a choke point 7. Downstream of this 6.-

  7 is connected to an 8-pipe

  plugging into a pipe 9 that leads to a canal

  10, which is protected against too high a pressure by a pressure limiting valve 11, this pressure limiting valve 11 serving at the same time to maintain in the pipe 10 a pressure

  predetermined predefined predefined, for example 16 bar.

  This pipe 10 leads to the feeding device

  of the hydraulic transmission, not shown in more detail.

  tail on the drawing, the driving of the vehicle also

  not shown in detail in the drawing.

  Line 5 drifts upstream of the point

  7, a pipe 12. A limiting valve

  pressure 13 is connected between the ducts

  12 and 9, this valve limits the maximum fall

  pressure between the two pipes 12 and 9. The

  12 leads to the inlet of the control pressure regulating valve 14, the outlet of which is connected the control pressure line 15. The evacuation line 16 of the control valve 14

  of the control pressure is in turn connected to the

9.

  Line 15 terminates at an inlet of a three-position, four-way distributor 17, which acts as a directional selection distributor.

  walk, and at both exits from which are connected the

  connections 18 and 19 which lead to the adjusting member,

  not shown in more detail in the drawing of the trans-

  hydraulic mission which, as already mentioned,

  is not represented in the drawing either. They result

  preferably to the two pressure chambers of a cy-

  receiver which can slide a piston

  an actuating a pre-control valve which, in turn, controls the supply of a setting cylinder in which a connected adjusting piston can slide 7.-

  to the transmission adjuster.

  At the second entrance of the selector

  17 of the direction of movement of the vehicle, is connected a pipe 20 which is in turn connected to the pipe 9, so that the pipe 20 is thus constantly subjected to the pressure under which is also the pipe 9 and which is determined over there

valve 11.

  In line 20 is connected a point

  throttle 21 downstream which is connected the channeling

  22 which leads to the outside of the casing 1 to the pressure chamber of the brake cylinder, not shown in greater detail in the drawing, or to the pressure chambers of the brake cylinders, not shown in more detail in the drawing. Moreover, a distributor 23 with three positions and two connections is attached to the pipe 22,

  this distributor playing the role of brake distributor.

  At the exit of this brake distributor 23 is connected a pipe 24 leading to the tank without pressure 4o The actuating member 25 of the brake valve 23 is connected to an actuating member 26 of the control valve 14 of the control pressure,

  so that by changing the position of the

  25 and therefore the adjustment of the brake valve 23, the preload of the spring of the regulating valve of

  the control pressure 14 is modified as well as the pressure

  order in line 15.

  In line 9 is also connected

  a pipe 27 which leads to the entrance of a distribution

  regulator 28 with two positions and three

  the actuating member 29 is in operative connection with

  rational with the actuator 30 of the distributor 17 for selecting the direction of travel of the vehicle. At one of the outlets of the distributor 28 is connected the pipe 8. -

  31 which leads to the adjusting member, not shown in FIG.

  tail on the drawing, of a diesel engine that is not no

  represented in the drawing and which leads to the transmission

  also not shown in the drawing.

  The second outlet of the distributor 28 is connected via line 32 to line 24

  ending at the reservoir 4. The distributor 17 for selecting

  the direction of movement of the vehicle is equipped with a

  an actuator 30 which can be operated at will.

  The control pressure regulating valve 14 is provided with an actuating member 33 by means of which the adjustment of the control pressure is directly influenced by

  the valve 14 for adjusting the control pressure. The se-

  actuating member 26 in operative connection with

  Rational with the actuating member 25 acts in the opposite direction of the actuating member 33- Between the actuating member 30 and the actuating member 33 of the control valve 14 of the control pressure of a

  part, and between the actuating member 30 and the actuator

  On the other hand, there is an operational connection, so that when actuating the actuating member 30, from the neutral position, first of all the distributor 17 of selection of the direction of movement of the vehicle is moved in its switching positions and then continuing to actuate the actuating member 30, the setting state of the actuating member 33 as well as that of the actuating member 29, continues to be constantly

  amended. The regulating distributor 28 is a distributor

  throttling device by which pressure can be

  maximum pressure at the pressure in the pipe

  9 and can be set to any lower pressure

until completely unloaded.

  The operating mode is as follows: The flow rate delivered by the auxiliary pump 29 passes through the pipe 5 at the throttling point 7 and through it and through the pipe 8, in the pipe 9 from which it arrives via the pipe 10 to the power supply device of the transmission. A constant pressure is then maintained in the pipe 10 through the valve 11. Upstream of the throttling point 7 accumulates a pressure which is determined by the importance of the flow passing through the throttling point 7 and which is limited

  upwards by the pressure limiting valve 13.

  This pressure is transmitted through line 12 to the

  valve 14 for adjusting the control pressure in the-

  what this pressure brought by the line 12 is

  the importance of this lowering being determined

  born as well by the position of the actuating member 26 as by the position of the actuating member 33,

  that is, the pressure settling in the canal

  15 is determined by the control valve 14 of

  the control pressure. This control pressure trans-

  placed in Line 15 is communicated through

  mediator of the distributor 17 for selecting the sense of de-

  placement of the vehicle respectively to one of the two

  lizations 18 or 19 and therefore to one of the sides of the

  setting the transmission. In the neutral position

  sent on the drawing of the distributor 17 for selecting the direction of movement of the vehicle, the same pressure reigns

  in both ducts 18 and 19, namely the pressure

  pre-determined level in the channeling

  tion 9 and which is transmitted through the

  nalisation 20 to the distributor 17 for selecting the direction of

moving the vehicle.

  This results in great safety because a control pressure control valve such as the

  valve 14 for adjusting the control pressure must always

  days include an actuator actuated by a spring.

1 0, -

  Then there is the risk that in the case of a bad device -

  maintained, and due to impurities in the oil, which are deposited on the edges of the adjustment member, there is a blockage of this adjustment member. But even when in the case of the circuit according to the present invention, the

  setting in the pressure regulating valve 14

  the control valve remains trapped by an impurity, if the accelerator pedal is put in the neutral position,

  the transmission is also set in the neutral position

  the throttle pedal is connected directly mechanically with the distributor 17 for selecting the direction of movement of the vehicle and, in the position

  neutral of the distributor 17 for selecting the direction of movement

  vehicle, the same pressure is established,

  previously described, through the channels

  tions 9 and 20 in the two pipelines 18 and 19,

  so that the adjusting member of the hydraulic transmission

  lique is moved to the neutral position. However, in the neutral position described by the vehicle direction selection distributor 17, the pipe 15 is also fed from the distributor 17 of the

  selection of the direction of movement of the vehicle with

  in the pipe 9, so that in the pipes 15 and 16 and thus on both sides of the valve 14 for adjusting the control pressure, the

same pressure reigns.

  If now the actuator 30 of the distributor 17 for selecting the direction of movement of the vehicle is actuated, and thus this distributor 17 for selecting the direction of movement of the vehicle is brought into one of the two switching positions, the control pressure pipe is then connected to one of the two pipes 18 or 19. The other of these two pipes 18 and 19 is connected via the pipe 20 to the pipe 9 and is thus fed by the 11. -

  constant pressure prevailing in this last channeling

  tion. Therefore, a pressure drop is generated between the pressures in the pipes 18 and 19, this pressure drop being dependent on the adjustment of the valve 14 for adjusting the control pressure.

  If the actuating member 25 of the

  brake actuator 23 is actuated, the actuating member 26 of the control pressure regulating valve 14

  is also operated through this distribu-

  and first of all the pressure drop between

  15 and 19 is reduced and therefore the fall of

  between the lines 18 and 19 is reduced and, as a result, the hydraulic transmission is

  neutral position. Only when the transmission is hy-

  hydraulics has reached its neutral position that, through

  23, a connection, constricted at least initially, is established between the pipes 22 and 24 and therefore between the pipe 22 and the tank 4 and the pressure in the brake pipe 22 is thus lowered so that the brake begins to tighten under the action of the energy accumulator until

  line 22 is completely devoid of pressure.

  the brake under the action of the energy accumulator is completely tightened. The throttling point

  21 prevents from Line 9 and through

  intermediate of the pipe 20, the fluid under pressure flows via the pipes 22 and 24

with too much flow.

  In order to be able to control the control valve 14 of the control pressure for a new start-up, it is necessary, because of the operational connection between the actuating members 25 and 26, that the brake valve 23 is first of all returned to its closed position, with the consequence that through the lines 9 and 20 and through the point 12.- throttling 21, a pressure is established again in the brake pressure line 22 , pressure thanks to

  which the brake is released. Between the body of action

  30 of the distributor 17 for selecting the direction of movement

  of the vehicle and the control pressure regulating valve 14, an operational link remains

  via the actuating member 30 of the

  pope 14 for adjusting the control pressure, with the consequence that in the neutral position of the distributor 17

  selection of the direction of movement of the vehicle, the

  Pope 14 control pressure setting can not be controlled. Only when one of the two control directions is controlled, which can also be controlled in the line 15 via the control pressure adjusting valve 14, a pressure of

  control that differs from the pressure in Line 9.

  As the actuator 29 of the distribution

  the scorer 28 is also in operational connection with the actuating member 30, this has the consequence that in the neutral position of the vehicle direction selection valve 17, the distributor 28 is in the position shown in the drawing and that, as a result, the pipe 31 is connected to the pipe 32 and therefore to the tank 4, so that the adjustment member of the diesel engine is set to the speed of rotation in

  run empty. Only when the governing body

  30 of the distributor 17 for selecting the direction of movement

  vehicle is actuated that the distributor 28 is also actuated and that a link is established between

  the pipes 27 and 31, so that through the intermediary

  re of this connection a pressure can be established in the

  pipe-31 and thus in the regulating member of the

  diesel engine. The connection between the actuating members 29 and 33 on the one hand and the member 30 on the other hand, is such that

  that during a constant movement of the operating organ

13.-

  From the neutral position, the valve 14

  control pressure, just like the distribution of

  28, are constantly being ordered more and more.

  In the casing 1 is provided a bore 41 in which are arranged a sleeve 42 and a sleeve 43. In the sleeve 42 there is again provided a bore 44 and in the sleeve 43 a bore 45. The two holes 44 and are aligned with each other and in these holes 44

  and 45 aligned one on the other is mounted a drawer turn-

  46 whose end 47 is connected via

  from a mechanical lever system to a pedal that is not

  more in detail on the drawing. In this rotating drawer 46 are formed two chambers 48 and 49 separated from each other by an intermediate partition 50. These chambers 48, 49 communicate with holes 51 and 52 in the sleeve 43 and constitute with them and the intermediate wall 50, the distributor 17 for reversing the direction of movement of the vehicle.

  Another part of the turntable 46 com-

  carries a chamber 53 closed by a plug 54 in which is formed a throttle bore 55 which opens into the chamber 56 in front of the end face of the rotary slide 46. In the wall of the chamber 53 is provided a piercing

  Narrowing down that communicates with a person

  58 in the socket 42, so that depending on the position

  rotation of the rotary slide 46, a transverse section

* dirty more or less important recovery is released.

  The axis of the bore 41 intersects the axis of the bore 61 which is closed upwards by a cover 60 fixed by two

screw 62.

  The middle portion of the rotary spool 46 is constituted by a flat web 59 in which is provided a threaded hole in which is screwed a threaded stud 63 fixed by means of a nut 64 which on its side placed downwards in the drawing, door a washer 65. Against this 14.- washer 65 applies the front face of a slide 66 slidable in the bore 61. In the part

  lower of the bore 61 a valve bushing 68

  against a shoulder 67 of the bore 61. Between the slider 66 and the valve bushing 68 is compressed a spring 69 which, on the one hand, holds the valve bushing 68 against the shoulder 67 and holds, On the other hand, the slider 66 applied to the washer 65. In the longitudinal bore of the valve bushing 68 can

  slide a valve spool 70 whose extension su-

  71 passes through a bore of the slider 66 and carries in a groove a retaining ring 72 which is applied against the upper face of the slider 66. Between the valve spool 70 and the slider 66 are compressed springs 73 which thus exert a force on the valve spool, effort whose importance depends on the distance between the face of the valve spool 70 placed in the top on

drawing and slide 66.

  In the same hole 74 of the valve bushing 68 can move a push-button 75 which is supported

  by means of springs 76 against the underside

  valve spool 70, so that through the intermediary of

  re springs 76 an effort, opposing the action of

  springs 73 is exerted on the valve spool 70.

  The parts 59 and 63 to 66 correspond to parts 25 and 26 of FIG. 1. The pusher 75 corresponds to the part 33 of FIG. 1. In the valve groove 68 radial holes 77 are provided which open into a bore 78 which is closed outwardly by a ball 79 pressed into the press and which communicates with a bore 80. These holes 78 and 80 correspond to the pipe

of Figure 1.

  Drilling 80 is intended to connect a

  which is, moreover, not

  in the patent application, which leads to the engine control member 15.-, while in the chamber 56 is maintained a constant preset pressure which communicates via the bore 55 to the chamber 53, a throttled connection can, however, be made with the bore 81 via the recess

  579 (see line 31 of Figure 1).

  At the shoulder 67 the bore 61 is transformed into the bore 82 which is closed by a cover 83 fixed by screws 84 and which comprises a threaded central bore in

  which is disposed a threaded stud 85, which is susceptible

  to pivot by being attachable by means of a nut 86

  in a selected position. The frontal face of the government

  Thread 85 thus limits the possible position of the spherical head 87 against which in turn

  the pusher 75 under the action of the spring 76. The spherical head

  that 87 is disposed on a lever 88 which is missé in the shaft 89 for actuating the brake, this shaft being arranged in FIG. 2 parallel to the plane of the drawing and before

  of this plane parallel to the lower edge of the casing 1.

  In a similar way to room 53 of

  turntable 46, the shaft 89 for actuating the brake com-

  door at its end a room 98 in the wall of the-

  a corner-shaped recess 99 for providing a throttling connection with the piercing 90 is provided

  This strangulation point 99 corresponding to the point of

  in the valve 23 of Figure 1.

  The embodiment according to the invention allows

  to slow down very gradually, avoiding situations

  in which there is through the transmission, drive by the moving

  of the vehicle, while the training torque is absorbed

  mostly thanks to the friction brake. Such a

  operation is also avoided when driving another user device, for example the pump of a hydraulic lift on a truck at 16.-

  fork, the internal combustion engine providing the

  must be set at a high speed of rotation, tan-

  say that at the same time the vehicle is moving slowly. On the contrary, there is always only one drive and the rotational speed of the output shaft is controlled

  in a very progressive way through the trans-

  hydraulic mission, or there is braking. Thus, not only does energy absorption and therefore unnecessary consumption of friction material and wear of the brake linings be spared, but the actuation and control of the vehicle is much simpler for the operation of the vehicle.

  only in the case of vehicles in which

  multaneously the internal combustion engine is set at a high speed by an actuating member, while

  with another actuator, the speed of

  placement of the vehicle must be braked.

17.-

Claims (9)

R E V E N D I C A T I 0 N S   1.- Control device for a vehicle   automobile with a primary energy source and a trans-   continuously adjustable mission preferably providing a forced transmission, especially a hydraulic transmission.   that the regulator is connected to a piston   setting whose position is determined by a control pressure whose magnitude is adjustable at will by means of a control pressure control valve, and with a brake biased by an energy accumulator, preferably a spring, and capable of being released by means of a pressure transmitted by a brake pressure line and controlled by an actuator of the brake, a control device characterized in that   the actuating member of the brake (25) is operably connected   with the valve adjuster (26)   (14) for adjusting the control pressure.   2.- Control device according to the   1, characterized in that, thanks to this functional connection, the first part, starting from the position   corresponding to the unlocked brake, of the   actuation of the brake actuating member, is associated, until the transmission output shaft is put in the stop position, in a process of adjusting the valve of the   setting (14) of the control pressure, while the   of the stroke of the brake operating member (25) is associated with an actuation process of   the valve (23) for lowering the brake pressure.   3.- Control device according to any one   conque of claims 1 or 2, characterized in that,   thanks to the operational connection, a modification of the control pressure beyond the value corresponding to   stopping the output shaft is then only possible when   that the brake pressure is brought to the total value cor-   responding to the brake completely unlocked. 18.-   4.- Control device according to any one   conque of claims 1 to 3, for a motor vehicle   in which the regulator of the primary energy source   The mayor is (also) capable of being adjusted by means of a control pressure adjustable by a control valve, a control device characterized in that the actuator (38) of the control valve (14) ) of the control pressure, is in operational connection with   the actuating member (29) of the regulating valve (28).   5.- Control device according to any one   conque of claims 1 to 4, characterized in that the   distributor for selecting the direction of movement of the vehicle   is realized in the form of a turn-table distributor   the rotating drawer body is equipped with a   1 5 in the form of a lever, against which a cou-   support scoop for the spring of the control pressure adjusting valve, the sliding axis of which is arranged, at least approximately, radially with respect to to the axis of the rotating drawer.   6.- Control device for a vehicle   automobile, with a primary source of energy and a trans-   mission that can be infinitely adjusted in both directions of output rotation and preferably   a forced transmission, in particular a hydraulic transmission   the regulator is connected to a control piston whose position is determined by a control pressure whose size can be adjusted at will by means of a control pressure control valve, a control pressure line being associated with each of the directions of output rotation, while at the setting of the neutral position of the transmission (ie the stop of the output shaft of the transmission) , the same pressure prevails in both   control pressure lines, preferably   positive control according to any one of the claims 19.-   1 to 5, characterized in that in the position of re-   corresponding to the neutral position, the two   the control pressure levels (18, 19) are fed   common by a control pressure of a predetermined level finished different from zero.   7.- Control device according to the claim   6 with a reversing valve in the direction of travel   of the vehicle, a pipe starting from a check valve   setting of the control pressure likely to be   born at will being connected to an inlet of this reversing valve of the direction of movement of the vehicle, while at each of the two outputs of this reversing valve of the   direction of movement of the vehicle, is connected to one of the   nizations leading to the regulator of the trans-   mission, control device characterized in that, -   at the second inlet of the reversing valve (17) of the direction of movement of the vehicle is connected a pipe (20) permanently transmitting a pressure of a predetermined level other than zero, whereas in its neutral position the valve (17) reversing direction of movement   of the vehicle, connects all four connections.   8.- Control device according to the   cation 7, characterized in that in the neutral position of   the valve (17) for reversing the direction of movement of the vehi-   cule, a throttling point is arranged on the link   to both control pressure lines.   9.- Control device according to the   cation 7, characterized in that the channel transmits   a pressure of a predetermined level, connected to an inlet of the reversing valve of the direction of movement of the vehicle, is the supply line of the transmission.