DE1954534C3 - Steering brake device for automobiles - Google Patents

Description

The invention relates to a steering-braking device for motor vehicles according to the preamble of Claim 1.

A steering-braking device for caterpillar vehicles is already known in which the caterpillar wheels of the drive axle have a differential gear drivable and otherwise the features according to the preamble of claim 1 are provided (DE-AS 368). The differential gear is not designed to be self-locking

For vehicles without caterpillars, which, however, are also designed for movement on difficult terrain are intended and can have several, for example three drive axles in addition to the steering axle the actuation of the steering axle is connected with braking of certain wheels of the fixed drive axles will.

To do this, the wheels of the steering axle of the moving vehicle are turned to the right, for example, and at the same time those not directed, i.e. H. fixed drive wheels on the right side of the Vehicle, d. H. braked on the inside of the curve. Will be those on the outside of the curve Drive wheels driven with sufficient torque, then every fixed drive axle is involved

a torque on the vehicle, which in the sense of a rotation of the vehicle to the right and that resisting torque counteracts which to keep the vehicle in a straight line endeavors and results from the weight of the vehicle, which is over the fixed driven wheels supported on the ground. This steering method is referred to below as "steering as a result of a speed difference between the drive wheels on the opposite sides of the vehicle"

As is well known, this is the difference between a self-locking differential gear and a classic one Differential gear that in addition to the axle shafts of the differential gear same torques mediating planet gears locking devices are provided, which each of these shafts in response to the they acting output torques automatically convey additional torques that affect the Support locking devices on the drive input of the differential gear.

In a known self-locking differential gear, they are concentric to the axle shafts arranged locking members each on the one hand with a rotatably connected to the associated axle shaft Provided friction piece and on the other hand with the axle shaft gear of the differential gear via start-up cams Connected in terms of drive (FR-PS 13 11 946). When torque is transmitted to the locking devices, the Start-up cam generates a force acting in the direction of the axle shaft, by means of which the friction pieces engage corresponding surfaces of the differential housing are pressed.

Would a vehicle use the well-known self-locking differential gear with the help of a speed difference between the opposing drive wheels be steered, with the speed difference by braking the drive wheels on one side of the vehicle is reached, this braking would still support the automatic locking effect and thus the achievement of a speed difference of the opposite Counteract drive wheels. Steering of such a vehicle with the aid of a speed difference between the opposing drive wheels is therefore not possible.

The invention specified in claim 1 is the The task is to improve motor vehicles with self-locking differential gears so that the self-locking differential gear a steering of the vehicle as a result of a speed difference between does not interfere with the drive wheels on the opposite sides of the vehicle

Advantageous embodiments of the invention can be found in the remaining claims.

Embodiments of the invention are described below with reference to the drawing, for example. It shows

F i g. 1 shows a view of a longitudinal section through a self-locking differential gear according to the invention, and

F i g. 2 a control device according to the invention in schematic and partially sectioned Representation, which with the differential gear according to F i g. 1 cooperates

A vehicle is not shown in its entirety in the drawings. It can be one or more have fixed drive axles, however, in the following for better clarity and also in the Drawings only a fixed drive axle in Considered their left and right wheels from the two axle shafts 1 and la of a self-locking differential gear 2 are driven, which has locking members 3, 3a to the shafts 1 and la as Reaction to output torques acting on the locking devices, additional torques to transmit automatically, so that the shafts 1 and 1 a can transmit different torques to the wheels of the drive axle, which is not the case with one

ίο lockable differential gear is not possible

The vehicle also has brake devices Fg and Fd , shown schematically, which are assigned to the left and right wheel of the drive axle and actuated independently of one another can be. The controls of these braking devices are different from those of normal vehicle brakes different, which act simultaneously on the left and right wheels at the command of the driver. That Finally, the vehicle also has a not shown

Steering axle on.

The self-locking differential gear 2 has a differential gear housing 4 which is rotatably mounted in a housing box 5, namely by means of Ball bearings 6 and 7. Furthermore, the usual ones Differential gears 8 and 8a provided which on an axis 9 of the differential gear housing 4 are rotatably mounted. The housing 4 consists of two Parts which are connected to one another by screws 10. The differential gears 8 and 8a

JO mesh with two axle shaft gears 11 and 11a, which center themselves on the toothing of the differential gears 8 and 8a and are connected to the axle shaft 1 or the axle shaft la are non-rotatably connected. The axis of rotation of shaft 1 and side gear 11 and

j> of shaft la and axle shaft gear 11a and the

The axis of rotation of the housing 4 lie on the same, in Fi g. 1 straight line I-I reproduced in dash-dotted lines,

which runs perpendicular to the longitudinal axis of the axis 9

To form the locking members 3 and 3a for the

Transmission of additional torques to each of the shafts 1 and la are to that of the shaft 1 and la facing end faces 13 and 13a of the axle shaft gears 11 and 11a stop cams (4 and 14a provided, which is radial and perpendicular to the axis I-l

• i3 run and directionally through this axis run through, furthermore, conical friction pieces 15, ISa provided, which are non-rotatably connected to the axle shaft 1 or la and on their end face 16 and 16a each have one of the starting cams 14 and 14a

so corresponding and intermeshing toothing exhibit. The shafts 1 and la are each provided with longitudinal grooves 17 and 17a, in which corresponding projections of the axially displaceable friction pieces 15 and 15a engage.

The starting cams 14 and 14a and the individual teeth of the corresponding teeth of the friction pieces 15 and 15a have a triangular profile, the The tip angle of the starting cams 14 and 14a or the teeth is, for example, 90 °, so that when applied a torque on the axle shaft gears 11 and Üa through the differential gears 8 and 8a the Start-up cams 14 and 14a not only take along the attractive teeth of the friction pieces 15 and 15a, but to push the latter out of the middle

μ strive, and ζαίγ with corresponding to the axis I-I Directed forces, which are essentially equal to the rotational drive force generated by the axle shaft gears 11 and Ua in the area of the middle

Diameter of the starting cams 14 and 14a is conveyed. In this way, the friction pieces 15 and 15a pressed against the associated friction surface 18 or 18a, which is also conical in the housing 4 are formed, which is set in rotation by a plate bevel gear 19, which with a bevel pinion 20 meshes with the main drive shaft 21 of the vehicle.

In addition to the same torques which the shafts 1 and 1 a of the axle shaft gears 11 and Ha, which are set in rotation by the compensating gears 8 and 8a, transmit the locking elements 3 and 3a to the shafts 1 and la automatically in response to output torques, which act on the locking devices, additional torques that are affected by the slippage or slip-free friction between the friction pieces 15 and 15a and the surfaces 18 and 18a of the compensation gear housing 4 originate.

In order to prevent the toothing of the side shaft gears 11 and Ha down to the bottom in the corresponding teeth of the differential gears 8 and 8a penetrate when the wheels U and 11a exert a pressure on the friction pieces 15 and 15a, are between the side shaft gears 11 and 11a and the Axis 9 support disks 22 and 22a are provided, which rest in flat surfaces 83 and 83a of the axis 9 and sit on pin 12, 12a of the axis 9. The discs 22 and 22a limit the movements of the wheels U and 11a towards the axis 9.

Instead of the interacting friction surfaces of the friction pieces 15 and 15a and the housing 4 conical to train, they can also be. In this case, several such surfaces can each with advantage Friction piece 15 or 15a be arranged, for example by layering friction disks.

When each of the one-sided braking devices Fc and Fd is actuated, adjusting motors 23 and 23a are put into operation, the action of which is opposite to the action of the locking devices 3 and 3a.

The motors 23 and 23a each have a Dewegiichen kingicoiDen l <\ D or 24a aut, which is able to push the associated friction piece 15 or 15a in a direction in which it is removed from the associated friction surface 18 or 18a of the housing 4 from the differential gear 2 takes off.

The braking devices Fc and Fd of the vehicle are actuated by a pressure medium which is supplied via lines 25 and 26. Each of the devices Fc and Fd has, for example, a cylinder by which a brake of a conventional type can be actuated.

The annular piston 24 and 24a, which are usable in this case, with particular advantage, are housed in chamber 27 and 27a parallel to the axis II displaceable A manifold 28 is provided which can be actuated by the pressure medium, the one or the other braking device Fd and Fc is supplied in order to allow pressure medium to flow into the chambers 27 and 27a via the connections 29 and 29a, which pressure medium is supplied to one or the other braking device Fd or Fg

The distributor 28 is provided with a control slide 30 which has an annular groove 31 and is slidably housed in a cylinder 32, which has a radial bore 33 which is connected via lines 34 and 35 to the pressure medium supply line 25 and 26 of the braking device Fp and Fc , respectively Furthermore, a radial bore 36 is provided, which is connected via lines 37 and 38 to the chamber 27 and 27a, respectively. A bore 39 is in communication with atmospheric pressure via a line 40, that is to say with an outlet 41 if the pressure medium is a liquid.

Depending on the position of the slide 30 in the cylinder 32, the annular groove 31 connects the bore 36 with the bore 33 or with the bore 39. The position of the slide 30 is set by means of two pistons 42 and 43, which are one behind the other and concentric to the slide 30 inside a chamber 44 which is part of the cylinder 32 is arranged. The two pistons 42 and 43 are tightly but slidably mounted in the chamber 44 which is equipped with a bore 45 which is connected via a line 46 to the pressure medium supply line 25 of the braking device Fo . Furthermore, the chamber 44 has a tube 47 on Hip via a line 48 with the pressure medium supply line 26 of the braking device Fc, which is connected. The bore 45 opens into the interior of the chamber 44 in the space between the piston 42 furthest away from the control slide and the chamber bottom 49, while the bore 47 opens into the space of the chamber 44 which is enclosed between the pistons 42 and 43 is.

Furthermore, a spring 50 is provided, which the slide 30 against the pistons 42 and 43 under Interposition of a piston 51 preloaded. If no pressure is built up in lines 25 and 26, then takes the slide 30 under the action of the spring 50 the in F i g. 2 position shown. Here is the Bore 36 is acted upon by atmospheric pressure via bore 39. In line 25 or 26 a Pressure built up, then the piston 42 or the piston 43 moves the slide 30 in FIG. 2 to the left, like this that the bore 36 is in communication with the lines 25 and 26 via the bore 33

A check valve 52 and 53 is arranged in each of the lines 34 and 35. These check valves only allow pressure medium from lines 25 and 2b to reach bore 33, ie prevent pressure medium flowing into line 34, for example when braking device Fd is actuated, from reaching line 26, braking device Fc then being in the rest position

The annular pistons 24 and 24a are arranged in a rotationally fixed manner and each act on the associated friction piece 15 or 15a via a pressure sleeve 54 or 54a. The pressure sleeves 54 and 54a are mounted coaxially on the Welk> 1 and la, with axial play opposite them. The pressure sleeves 54 and 54a are guided in a cylindrical inner bore of the housing -, it 4 and each rest with their end face 55 or 55a on the adjacent end face 56 or 56a of the friction piece 15 or 15a. Each pressure sleeve 54 or 54a is supported on the adjacent annular piston 24 or 24a via an axial needle bearing 57 or 57a.

Each annular piston 24 or 24a has a tubular extension 58 or 58a, which has a transverse wall 59 or 59a of the chamber 27 or 27a penetrated through a bore 60 or 60a. the Extensions 58 and 58a protrude from chambers 27 and 27a. Each extension 58 or 58a instructs its end remote from the piston 24 or 24a Abutment 61 and 61a. On each extension 58 or 58a is a return spring 62 or 62a between the abutment 61 or 61a and the wall 59 or 59a

intended. There is no pressure in chambers 27 and 27a constructed, then the springs 62 and 62a hold the pistons 24 and 2 * a in the in F i g. 1 reproduced Positions in which they do not exert any pressure on the pressure sleeves 54 and 54a, so that the axial needle bearings 57 and 57a need not be effective in the axial direction.

Seals 63 and 64 or 63a and 64a are provided to seal the chambers 27 and 27a. the Seals 63 and 63a are each arranged in an annular groove within the bore 60 and 60a, respectively, while the seals 64 and 64a each in an annular groove on the circumference of the piston 24 and 24a are housed.

Each of the braking devices Fo and Fc can be acted upon by a steering actuation device 65 which responds to the turning of the wheels of the steering axle of the vehicle.

The steering actuator 65 has manifolds 66 and 66a which lead to lines 25 and 26, respectively Supply pressure medium, the pressure of which corresponds to the size of the angle of the wheels to the right (distributor 66) or to the left (distributor 66a,) rises.

The steering actuator is for example equipped with a rack 67, which of a Pinion 68 can be actuated, which is rotatably connected to the steering column of the vehicle. The rack 67 is from their in F i g. 2 reproduced center position to the left and right, with a Vers'oll away from the size of the turning of the wheels is proportional to the steering axis. Each distributor 66 or 66a has a piston 69 or 69a. The two Pistons 69 and 69a are arranged on both sides of the rack 67 and in a common cylinder 70 displaceable, between each piston 69 or 69a and the adjacent end of the rack 67 a Spring 71 or 71a is switched on. At each end of the Cylinder 70, a wall 72 or 72a with a bore 73 or 73a is provided. The wall 72 or 72a is arranged between the piston 69 or 69a and the end wall 74 or 74a of the cylinder 70.

Each piston 69 or Wa is provided with a channel 75 or 75a which, when the piston 69 or 69a is in a certain position in the cylinder 70, connects a chamber 82 or 82a to be described with the outlet 41. A valve 76 or 76a is used to close the bore 74 or 73a and has a needle 77 or 77a which closes the channel 75 or 75a when the piston 69 or 69a comes into contact. The valves 76 and 76a are each preloaded in the closing direction by a spring 84 or 84a.

The chambers 81 and 81a of the cylinder 70, which are enclosed between the walls 74 and 72 or 74a and 72a, are connected to an auxiliary pressure medium source 79 via lines 80 and 80a. The chambers 82 and 82a of the cylinder 70, which are delimited by the inner wall 72 and the piston 79 and by the inner wall 72a and the piston 69a, are connected to the feed lines 25 and 26 of the braking devices Found Fg .

Regardless of the embodiment of the invention, a correspondingly configured vehicle can be steered as follows. First of all, a vehicle with a self-locking differential gear is considered, which does not have a steering actuation device 65, in which rather the braking devices Fd and Fg are actuated directly by the driver, who controls the supply of pressure medium to lines 25 and 26 for this purpose.

If the driver wants to take a right turn, for example, then he brakes the right drive wheel of the vehicle driven by the shaft la by means of the braking device F /> in conjunction with turning the wheels of the steering axle to the right. Pressure medium is then conveyed into the line 25, which also reaches the space of the chamber 44 via the line 46, which is delimited by the chamber bottom 49 and the piston 42. The same pressure medium reaches the bore 33 of the distributor 28 via the line 34. The check valve 53 prevents the pressure medium from reaching the braking device Fc , which is in communication with the atmosphere via the channel 74a and is in the rest or relief position.

The piston 42 exposed to the action of the pressure medium moves the piston 43 and the slide 30 in F i g. 2 to the left, against the action of the spring 50. As a result, the bore 33 with the bore 36 contacted. The pressure medium reaches the chamber 27 and 27a and acts on the pistons 24 and 24a, which via the axial needle bearings 57 and 57a and the pressure sleeves 54 and Ma, the friction pieces 15 and 15a push away from surfaces 18 and 18a of housing 4. As a result, the left unbraked drive wheel compared to the right drive wheel with a higher speed or Speed is driven.

If the driver wants to interrupt the cornering of the vehicle, then he stops turning Steering wheels and the supply of pressure medium to the line 25. By the spring 50, the slide 30 is then in the in Fig. 2 position shown moved. the

J5 bore 36 of distributor 28 is then connected to outlet 41, as are chambers 27 and 27a. the Springs 62 and 62a push the pistons 24 and 24a away from the friction pieces 15 and 15a, which then move again freely on the friction surfaces 18 and 18a of the housing 4

• Can press υ.

The pressure of the annular piston 24 and 24a on the wedge pieces 15 and I5a depends on the pressure of the Pressure medium in line 25 from, and thus from the action of the vehicle driver. Does this one want that If the vehicle drives to the right in a curve with a strong curvature, then it applies forceful braking by allowing pressure medium under high pressure to flow into line 25. In this case it is the pressure of the pistons 24 and 24a on the friction pieces 15

so and 15a strong and can be greater than the pressure exerted by the stop cams 14 and 14a on the corresponding teeth of the friction pieces 15 and 15a is exercised, what the self-locking differential gear 2 converts it into a classic differential gear that has the same torques as shafts 1 and la conveyed

The processes are the same or similar when the driver makes a left turn with the vehicle, wherein the pressure medium flowing in via line 48 acts directly on piston 43

The above is the mode of operation of a vehicle with a steering axle and a drive axle has been described. Most of the time, however, the vehicles have several drive axles, each with a self-locking differential gear, or the (which is the rule for on every terrain operable vehicles) in parallel with a single self-locking differential gear.

work. The braking devices Found Fp are also provided and the chambers 27 and 27a of each differential gear are fed in parallel via lines 37 and 38, while the braking devices Fd and Fa of each axle are supplied with pressure medium via lines 25 and 26 in parallel.

A vehicle with a self-locking differential gear is considered below which is equipped with the steering operating device 65 for operating the braking device Found Fg .

In Fig. 2, the steering operating device 65 is shown in the state that corresponds to straight-ahead travel of the vehicle. The rack 67 assumes the central position and the pistons 69 and 69a are so that the chambers 82 and 82a provided on both sides of the rack 67 are in communication with the outlet 41, the pressure medium in the lines 25 and 26 being under atmospheric pressure and the braking devices Found Fc not actuated.

If the driver wants to drive the vehicle in a right-hand bend, for example, then he actuates the steering in such a way that the rack 67 by means of the pinion 68 in FIG. 2 is moved to the right and assumes a position that depends on the size of the turning of the steering wheels. The rack 67 compresses the spring 71, which in turn moves the piston 69 until the channel 75 is closed by the needle 77. The displacement of the piston 69 then results in the opening of the valve 76, to be precise against the action of the spring 84, so that pressurized pressure medium can flow from the chamber 81 into the chamber 82. When the pressure prevailing in the chamber 82 or the resulting force acting on the piston 69 exceeds the force of the spring 71 acting in the opposite direction, the piston 69 moves to the left so that the valve 76 closes. By suitable selection of the spring constant of the spring 71, a pressure can be built up in the line 25 connected to the chamber 82, which pressure depends on the size of the turning of the steering wheels to the right, for example is proportional to the size of the turning. The pressure of the pressure medium in the line 25 causes the braking device Fo to be actuated and thus, via the distributor 28, the application of pressure by the annular piston

ίο 24 and 24a on the friction pieces 15 and 15a.

This also applies to the distributor 66a, which of the line 26 is a pressure medium with such a pressure feeds, which also depends on the size of the turn of the steering wheels to the left.

When the vehicle is set to drive straight ahead again, the spring 71 and the in The pressure prevailing in the chamber 82 pushes the piston 69 to the left in FIG. The channel 75 is then with the Reimbursement b / .w. the outlet 4i veiuuiiuen, mj uau the pressure in the line 25 drops and the action of the braking device Fd ceases. The slide 30 moves in Fig. 2 to the right, under the action of the spring 50, what the chambers 27 and 27a with the Return line or the outlet 41 connects, so that the friction pieces 15 and 15a again on the friction surfaces 18 and 18a of the differential gear housing 4 are in contact.

Since the pressure of the pressure medium supplied to the lines 25 and 26 from the steering actuator 65 depends on the size of the turning of the steering wheels, are the braking effect and that of the Ring piston 24 and 24a applied to the friction pieces 15 and 15a, the greater the pressure Impact is. A strong impact leaves the self-locking differential gear 2 as a classic Differentials work.

For this purpose 2 sheets of drawings

Claims (5)

Patent claims: 1. Steering-braking device for motor vehicles with a possibly driven steering axle and at least one fixed drive axle, c | eren wheels or groups of wheels are driven via a differential gear, each wheel or group of wheels of each fixed drive axle being assigned a unilateral braking device, which is controlled by a hydraulic Control device can be actuated, which responds to the angle of the steering handwheel in such a way that when the vehicle is moving, when the steering handwheel is turned to the right or left, the braking device of the right or left wheel or the corresponding wheel group ι i of the driven fixed drive axle is actuated, wherein Furthermore, the differential gear can be locked and the axle shafts of the drive axle divided by the differential gear are driven and the locking of the differential gear is released by the hydraulic control when the right or left brake device is actuated, characterized in that the Locking elements (3 and 3a ) arranged concentrically to the axle shaft (1 or la) in the differential gear (2) have, on the one hand, a friction piece (15 or \ 5a) non-rotatably connected to the axle shaft (1 or \ a) and, on the other hand, to the axle shaft gear ( 11 and Ua) of the differential gear (2) are drivingly connected via start-up cam (14 and 14), thus through the run-up cam (14 and I4A) for the transmission of torque to the locking members (3 and acting in Achswellenritätung force 3a) for pressing the Friction pieces (15 and 15a) in a corresponding friction surface (18; betw. 18a) of the differential gear housing (4) is generated, and that the hydraulic control is based on a pressure-medium-actuated adjusting motor (23 or 23a) with an axially displaceable annular piston (24 or 24a) arranged concentrically to the axle shaft (1 or la) -to acts, which acts on the locking member (3 or 3a) and, when actuated, counteracts the force emanating from the starting cams (14 and 14a) and the friction piece (15 or 15a,} from the surface (18 or 18a) of the Differential gear housing (4) moved away- ⁴ ^ 2. Steering-braking device according to claim 1, characterized in that one of the one of the braking devices (Fd or Fc) supplied pressure medium actuated w distributor (28) is provided in the hydraulic control, via which part of the pressure medium into the chambers ( 27 or 27a) of the adjusting motor (23 or 23a) arrives 3. Steering-braking device according to claim 2, characterized in that the distributor (28) has a control slide (30) which is guided displaceably in a cylinder (32) and of two pistons arranged one behind the other and concentrically to the control slide in a chamber (44) (42 and 43) for supplying the right or left «> of the braking devices (F ₀ or F ₀ ) supplied pressure medium into the chambers (27 or 27a) can be actuated, the space of the chamber (44) between the Control slide (30) the most distant piston (42) and the chamber bottom (49) ^b5 with which the one braking device (Fd) supplied pressure medium can be acted upon, while the space of the chamber (44) between the two pistons (42 and 43) can be acted upon with the pressure medium supplied to the other braking device (Fa) 4, steering-braking device according to claim | or 3, characterized in that actuatable distributors (66 or 65a) are provided in the hydraulic control with the pinion (68) of the steering, which control the pressure of the pressure medium supplied to the right and left braking device (Fo or Fg) Change it to the right or left according to the amount of turn of the steering wheel. 5. Steering-braking device according to claim 4, characterized in that each distributor (66 or 66a) has a first and a second chamber (81b? W. 81a and 82 or 82a) , between which a wall (72 or 82a). 72a) is provided with a bore (73 or 73a) that can be closed by a valve (76 or 76a) , the second chamber (82 or 82a,} being separated from the wall (72 or 72a) and a movable piston (69 or 69a,}, which has a channel (75 or 75a) connecting the second chamber (82 or 82a) at a certain piston position to the outlet (41 or 4IaJ), which is connected by a channel (76 or 75a) on the valve. 76a) provided needle (77 or 77a) when the piston (69 or 69a) is in contact with the needle (77 or 77a) can be closed by the steering control, which via the pinion (68) g * f a rack (67) is transmitted, the rack (67) arranged in the distributors (66 or 66a) being displaceable from a central position in opposite directions and via springs (71 and 66a) d 71a) between the two ends of the rack (67) and the pistons (69 and 69a) provided on both sides thereof cooperate with the latter and the first chambers (81 and 81a) being connected to a pressure medium source (79), while the second chambers (82 or 82a) are in connection with the braking device (Fd) or with the braking device (F _G ) .