SE534146C2 - Braking device and method of braking - Google Patents

Description

534 146 speeds. A retarder is dimensioned for a certain braking torque, for example 3500 Nm. In order not to make the dimensioned torque too high, an electronic limitation is arranged which limits the torque to the desired / dimensioned torque. At increased speeds, increased effects also occur, which is why the power is also arranged to be limited at a certain power, for example 500 kW. Thus, with increasing PTO shaft speed, a curve is obtained up to the desired braking torque called full fill curve, then a plateau and finally a power limitation curve at sufficiently high PTO shaft speeds.

In a hydraulic retarder, the braking torque is generated hydrodynamically by means of oil between a stator and a rotor thereof. The space between the stator and the rotor is called the torus and the output braking torque depends on the degree of filling of oil in this space. Thus, by controlling the oil pressure in said space, the degree of filling, i.e. the proportion of oil in the space is regulated.

Before the retarder begins to produce an outgoing braking torque, the space around the stator and rotor must be filled with oil.

A disadvantage of a primary retarder is that interruptions in the braking torque occur during a shifting step of the shifting unit, and / or when depressing the clutch of the vehicle. A hydraulic retarder must then be drained of oil. Furthermore, different braking torques are obtained on the drive wheels at different gear stages. An advantage of the primary retarder is that at low speeds when low gear is engaged, a good braking torque is obtained in comparison with the secondary retarder. Thanks to the good properties at low speeds, a primary retarder can be dimensioned down. However, this has the disadvantage that poorer properties are obtained at high speeds. A primary retarder is experienced when shifting negatively by the driver due to. interruptions in braking torque.

Since the secondary retarder is arranged to act directly on the PTO shaft, this has the advantage that torque interruptions do not occur during shifting or if the driver depresses the clutch. The secondary retard is more efficient at high speeds as the wheel brakes of, for example, a truck become hotter. A disadvantage of the secondary retarder, however, is that the braking torque is relatively poor at low speeds, which can be a problem when, for example, driving on downhill serpentine roads.

The braking torque slope of the full fill curve of the retarder can be affected by dimensioning the retarder / vanes of the retarder differently, where larger retarder / blades result in higher braking torque, and / or by changing the gear ratio, where higher gear ratio leads to higher braking torque. Higher gears enable smaller retarders / blades. Higher gear ratio, however, at higher PTO shafts at the plateau section means that small pressure differences give large torque variations, which impairs controllability. In the secondary retarder, gear ratio is chosen as a compromise between low-speed performance and controllability and idling speeds. retarder / buckets result in larger components that take up more space, increase weight and also increase cost. BACKGROUND OF THE INVENTION An object of the present invention is to provide a device for braking vehicles which enables effective braking action at both low and high speeds of the vehicle, i.e. at low and high speeds of the PTO shaft.

A further object of the present invention is to provide a method for braking vehicles which enables effective braking action at both low and high speeds of the vehicle, i.e. at low and high speeds of the PTO shaft. SUMMARY OF THE INVENTION These and other objects, which appear from the following description, are achieved by means of a braking device, a method of braking and a motor vehicle as above, and further having the features set forth in the characterizing part of appended claims 1 and 5, respectively. Preferred embodiments of the braking device and method are defined in claims 2-4 and 6-8.

According to the invention, the objects are achieved with a braking device for braking a motor vehicle provided with a driveline comprising a motor for driving the vehicle, a shifting device connected to the engine arranged to different gear ratios, and drive wheels, the shifting device comprising a main gearbox with a main shaft and a range to which driving force is arranged to be transmitted from the main shaft and an output shaft, which gear shift device is interchangeable between a high-range range, where the output shaft is arranged to rotate at speeds corresponding to a certain gear ratio, and a low-range range, where the output shaft is arranged to rotate with a lower speed corresponding to a certain lower gear ratio relative to the input shaft provided, the output shaft being arranged to transmit driving force to the drive wheels, the braking device being connected to the driveline so that braking of the drive wheels is allowed for braking the motor vehicle, revs The braking device is to be arranged to act on the braking action on the input shaft of the range change device.

Because the device is arranged to allow braking action on the input shaft of the gearshift device, good braking torque is obtained on the driving wheels and consequently effective braking action by means of retarders at both low and high speeds / low and high PTO shafts. 534 146 According to one embodiment, the braking device is a retarder device, for example a hydraulic retarder device or an electromagnetic one. In this case, any suitable retarder device can be used.

According to one embodiment, the rotation of the braking device is intended to be effected by means of a direct connection with said input shaft.

This means that only one retarder is required, whereby a simple and reliable construction is obtained. Furthermore, this entails space advantages.

According to one embodiment, the braking device is arranged to exert said braking action via a shifting device. In this case, placement of the braking part itself, ie. the retarder, is placed in a suitable place and does not take up space between the main gearbox and the range change device.

According to the invention, the objects are also achieved with a method for braking a motor vehicle provided with a driveline comprising a motor for driving the vehicle, a shifting device connected to the engine arranged to different gear ratios, drive wheels, the shifting device comprising a main gearbox with a main shaft and a gearshift device. shaft to which driving force is transmitted from the main shaft and an output shaft, which range gear device is interchangeable between a high-range range, the output shaft rotating at speeds corresponding to a certain gear ratio, and a low-range range at which the output shaft rotates at a lower speed corresponding to a certain lower gear ratio relative the input shaft, the output shaft transmitting driving force to the drive wheels, comprising the step of braking the drive wheels via the driveline for braking the motor vehicle, comprising the step of braking the vehicle to, by exerting the braking action on gear shifting devices, ns input shaft.

Because the braking action takes place on the input shaft of the gearshift device, good braking torque is obtained on the driving wheels and consequently effective braking action by means of retarders at both low and high speeds / low and high PTO shafts. According to an embodiment of the method, the step of applying the braking effect is effected by means of a retarder device, for example a hydraulic retarder device or an electromagnetic one. Any suitable retarder device can be used.

According to one embodiment, the method comprises the step of exerting said braking action directly on the input shaft. This means that only one retarder is required, whereby a simple and reliable construction is obtained. Furthermore, this entails space advantages.

According to one embodiment, the method comprises the step of exerting said braking action via a shifting step. In this case, placement of the braking part itself, ie. the retardem is placed in a suitable place and does not take up space between the main gearbox and the range change device.

DESCRIPTION OF THE DRAWINGS The present invention will be better understood with reference to the following detailed description read in conjunction with the accompanying drawings, in which like reference numerals refer to like parts throughout the many views, and in which: Fig. Arranged in the motor vehicle and an auxiliary braking device arranged 1 schematically show a motor vehicle comprising master brakes according to the present invention of the motor vehicle; Fig. 2 schematically shows an auxiliary brake device arranged according to the invention; Fig. 3 schematically shows braking torque as a function of PTO shaft speed of an auxiliary braking device according to an embodiment of the present invention; Fig. 4 schematically shows an auxiliary braking device arranged in connection with a gear shifting device according to an embodiment of the present invention; Fig. 5 schematically shows an auxiliary brake device arranged in connection with a range change device according to a further embodiment of the present invention; and Fig. 6 schematically shows an auxiliary brake device arranged in connection with a range change device according to yet another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Fig. 1 schematically shows the placement of brakes on a heavy motor vehicle 10, such as a truck auxiliary brake device according to a variant of the present invention. According to fi g. 1, the vehicle 10 is provided with a driveline 20 which includes a motor 30 for and Fig. 2 schematically shows the arrangement of a drive of the vehicle, a shifting device 40 connected to the engine arranged to provide different gear ratios, a cardan shaft 60, an end gear 70 which according to a variant is a differential gear, drive shafts 80, and drive wheels 82, 84.

As shown in Fig. 2, the shifting device 40 comprises a main gearbox 42 with a main shaft 43 and a range shifting device 50 in the form of a planetary gear including an input shaft 52 to which driving force is arranged to be transmitted from the main shaft 43 and an output shaft 54.

The range gear 50 is interchangeable between a high range range, the output shaft 54 rotating at a speed corresponding to a certain gear ratio, normally gear ratio 1 relative to the input shaft 52, and a low range range with the output shaft 54 rotating at a lower speed corresponding to a certain lower gear ratio relative to the input range. the shaft 52. The output shaft 54 is arranged to transmit the driving force to the PTO shaft 60, 534 146, the PTO shaft being arranged to transmit the driving force to the driving wheels 82, 84 via said end gear 70 and said drive shafts 80.

The vehicle comprises braking means 90a, 90b, 90c 90d, 90e 90f in the form of wheel brakes adapted to act against the wheels 82, 83, 84, 85, 87, 89 of the vehicle.

The brake means 90a, 90b, 90c 90d, 90e, 90f are arranged to be applied by means of a main brake.

According to the invention, the vehicle 10 further comprises an auxiliary braking device 100 in the form of a retarder device 100. According to an embodiment of the invention, the retarder device 100 is a hydraulic retarder device 100 arranged to generate output braking torque hydrodynamically.

The retarder device 100 is connected to the driveline 20 so that braking of the axles included in the driveline for braking the driving wheels is effected, see Fig. 1. According to the present invention, as shown in Fig. 2, the retarder device 100 is arranged to act on the input shaft. 52 of the range shifter 50 so that its gear is utilized. 100 is consequently arranged in such a way that the braking torque produced by the braking action by means of the retarder device The retarder device 100 on the input shaft 52 of the range change device 50 is only interrupted by the range change step thereof.

Fig. 3 schematically shows the PTO shaft braking torque as a function of PTO shaft according to an embodiment of the present invention. According to this example, the retarder is a hydraulic retarder with rotor and stator in the form of a paddle device, which retarder is arranged according to the invention according to Figs. 1 and 2 to act on the input shaft of the range change device.

The electrical limitation of the PTO shaft braking torque in this example is the same at both the low and high range ranges. Power curves E1-E5 are drawn. In this example, there is also a power limitation in this example, according to the power curve E5 in the example. In Fig. 3, the range change device has a gear ratio in Fig. 3 in the low range range, which can be, for example, 3.75. The hydraulic retarder could have a gear ratio, for example 3.

When operating in the low-range range, due to the retarder device 100 being arranged to act on the input shaft 52 of the range-changer 50 in this of the range-changer 50, for example 3.75 multiplied by the gear ratio of the retarder-device 100, for example 3. Consequently, the gear of the range-changer is used here. As a result, a higher speed is obtained of the retarder device 100, which results in a faster rise of the filling curve L for the low-range area relative to the curve H, which is shown in Fig. 3, so that the desired speeds / cardan shaft speed. example a gear which is the gear plateau is reached already at very low to achieve a significantly higher braking torque due to the fact that as in this example there is a gear on the retarder device 100. In the example according to Fig. 3 the torque is limited also for Further possible low range, but since the power is relatively low at lower speeds lcardane shaft speed, it is possible to have a higher braking torque when driving in the low range area without this affecting dimensioning of retarder, as shown by arrow A and the dashed alternative portion L 'of the filling curve L. By letting the retarder device 100 include the shaft in the range change device, the retarder device 100 can also have a lower gear ratio compared to a secondary retarder and thus provide other advantages such as better controllability, act on the lower idle losses, and reduced space consumption.

The filling curve during operation in the low-range area, and consequently also during operation in the high-range area, the retarder device 100, i.e. the vanes / vane device of the same, different, where larger vanes entail greater braking torque, and / or have different 100, ie. is influenced by dimensioning gear ratio on the retarder device shift device of 534 145 retarder device 100, where higher gear ratio leads to higher speeds of the paddle device and consequently steeper filling curve.

When operating in the high-range range, the retarder device 100 arranged to act on the input shaft of the range shifter in this example obtains a gear which is the gear ratio of the range shifter, which in the high range range according to an example is 1, multiplied by the gear ratio of the retarder device 100, hereby obtained. operation in the high-range area the same effect as with a secondary retarder, ie. as if the retarder device 100 were arranged to act on the output shaft of the range shifter / propeller shaft. This is shown in Fig. 3 of the fill curve H for operation in the high-range area. For a secondary retarder, that curve is obtained during operation in both the high and low range range.

Thus, by arranging the retarder device 100 so that it acts on the input shaft 52 of the range shifter 50, good cardan shaft braking torque and consequently effective braking action is obtained by the retarder device 100 at both low and high speeds / low and high cardan shaft speeds.

Figs. 4, 5 and 6 schematically show embodiments of the auxiliary brake device 100 according to the present invention where the auxiliary brake device is designed as a hydraulic retarder device 100.

Fig. 4 schematically shows an auxiliary brake device 100 arranged in connection with gear shifting device 50 according to an embodiment of the present invention. The auxiliary braking device 100 consists of a hydraulic retarder device 100, the braking torque being arranged to be generated hydrodynamically by means of a suitable medium such as oil.

The retarder device 100 comprises a retarder gear 110 and a retarder 120 connected to the retarder gear. The retarder 120 comprises a stator 122 and a rotor 124, the rotor 124 being arranged to rotate with a retarder shaft 126. The oil is presently arranged between the stator 122 and the rotor 534 146 11 124 of the retarder 120. The space between the stator 122 and the rotor 124 is called the torus and the output braking torque depends on the degree of filling of oil in this space. The retarder 120 comprises a vane device 128 including vanes arranged at the rotor 124 and the stator 122 that when the retarder device 100 is activated is rotated in the oil so that a braking moment occurs.

The gear shift device 50 comprises an input shaft 52, a gear configuration 56 and an output shaft 54. The input shaft 52 of the gear shift device 50 is arranged to receive transmitted power from the vehicle's engine (not shown) via the vehicle's main gearbox (not shown). The output shaft 54 is arranged to transmit the power to the driving wheels of the vehicle via the gearshift configuration 56 of the gear shifting device 50, preferably via the cardan shaft of the vehicle. This is shown in Fig. 1.

The gear configuration 56 is arranged to either carry the driving force directly from the input shaft to the drive wheels in a so-called high-range position, or by downshifting in a so-called low-range position. the gearshift configuration 56 comprises a ring gear 57 displaceable in the direction of the arrow B with internal teeth and clutch teeth, a sun gear 58 which is attached to the input shaft 52, and depending on the gearbox type a number of planet gears 59, for example three, four or five planet gears 59 arranged between the ring gear 57 and the sun gear 58.

The planet gears 59 are mounted in the output shaft 54 which at the same time acts as a planet gear holder.

The retarder gear 110 comprises a first gear 112 which is arranged to be supported on the input shaft 52 and rotate with the input shaft 52, and a second gear 114 which is arranged to be brought into engagement with the first gear 112 so that it is rotated by means of the first gear 112 upon actuation of the retarder device 100. The second gear 114 is arranged to be supported on the retarder shaft 126. The retarder gear 110 is arranged to transmit by rotation the rotation of the input shaft 52 to the retarder 120 so that the rotor 124 rotates, according to this variant of the invention, with a higher rotational speed, so that a higher braking torque is obtained. 534 146 12 By arranging gearing on the retarder device 100, i.e. by means of the retarder gear 110 of the retarder device 100, the higher gear ratio gives higher speeds of the rotor / vanes and consequently a steeper filling curve in accordance with fi g. 3, i.e. the desired braking torque is achieved faster.

A further advantage of the retarder gear 110 is that the retarder 120 can be placed in a suitable place for reasons of space and does not take up space between the main gearbox and the range gear device 100, see Figs. 1 and 2, of the vehicle, where only the gears of the gear device 56 occupy mwmme. 5 schematically shows an auxiliary brake device 100 arranged in connection with a gear change device according to a further embodiment of the present invention. The embodiment according to Fig. 5 is substantially the same as the embodiment according to Fig. 4 and differs from the embodiment according to Fig. 4 only by the design of the retarder gear 110.

The retarder gear 110 according to the embodiment of Fig. 5 comprises a first gear 112 which is arranged to be supported on the input shaft 52 and rotates with the input shaft, and a second gear 114 arranged to be supported on the retarder shaft 126. The retarder gear 110 further comprises an intermediate gear 116 which is arranged to be engaged with the first gear 112 so that it is rotated by the first gear 112 upon actuation of the retarder device 100, and arranged to be engaged with the second gear 114 so that it is rotated in the same direction relative to the input shaft 52. The retarder gear is arranged to transmit the gear of the input shaft 52 to the retarder 120 by means of gear so that the rotor rotates, according to this variant of the invention, at a higher rotational speed, so that a higher braking torque is obtained.

In this case, higher speeds of the rotor / blades are also obtained due to the higher gear ratio. Because the retarder gear 110 comprises an intermediate wheel 116 534 146 13 as above, the advantage is obtained that the retarder shaft can be placed further from the input shaft 52, which entails further possibilities for positioning the retarder 120. With the retarder gear according to Fig. 4, larger gears of the retarder gear are required to provide this, which takes up more space.

Fig. 6 schematically shows an auxiliary brake device 100 arranged in connection with gear shift device 50 according to yet another embodiment of the present invention. The embodiment according to Fig. 6 differs from the embodiment according to Figs. 4 and 5 only in that the retarder device 100 does not comprise a retarder gear but is instead directly arranged to be supported by the input shaft 52. Consequently, the retarder device 100, i.e. rotation of the rotor 124 intended to be effected by means of a direct connection with said input shaft 52.

The retarder device 100 is thus arranged around the input shaft 52 of the range change device 50 in such a way that it rotates with the input shaft. In this case, the retarder device 100 has no gear ratio but receives the same speed as the input shaft 52.

Because the retarder device 100 according to this embodiment is not provided with a retarder gear, it is dimensioned according to this variant larger than the embodiment according to Figs. 4 and 5, in such a way that it has a larger outer diameter, so that the vanes are placed further from the center of rotation. whereby higher braking torque is obtained.

By dimensioning the retarder device 100 larger, as above, a greater braking torque is obtained at low rotational speeds. By arranging the retarder 120 to rotate with the input shaft 52, no retarder gear is required, which may be advantageous if necessary for space reasons, and which enables a simpler construction, with fewer components.

The invention has been described in the above embodiments for a hydraulic retarder device. However, any suitable auxiliary brake may be provided to provide a braking action on the input shaft of the gear shift device so that the driving wheels, when the auxiliary brake is activated, are braked.

For example, other suitable retarder devices such as an electric / electromagnetic retarder device can advantageously be arranged to act on the input shaft of having a corresponding function and thus obtain the above-mentioned advantages. According to a variant, an electromagnetic retarder device comprises a stator comprising electromagnets, as well as two rotor disks. substantially other medium can be used in a retarder device, in addition to oil. For example, a retarder device with water as medium can be arranged to act on the input shaft of the range change device with substantially corresponding function resulting in the above-mentioned advantages.

The retarder arrangement could also comprise a retarder gear without gear, which means that the retarder device can be placed in any place and still be rotated at the same rotational speed as the input shaft of the range changer.

The input shaft 52 of the range change device 50 also includes the output shaft from the main gearbox 42, i.e. the rotation of the shaft of the output shaft of the main gearbox corresponds to the rotation of the input shaft of the range shifter 50.

Above, motor vehicles have been described where the output shaft is arranged to transmit power to the drive wheels via a propeller shaft. According to a variant, the driveline of the motor vehicle could be configured so that the output shaft directly transmits the power to the rear gear, ie. that the gearbox is arranged in connection with the rear driving wheels. A front-wheel drive vehicle is also conceivable. 534 146 Where quantities such as braking torques, effects and gears are only examples, and any suitable dimensions / adjustments can be made without departing from the scope of protection, as defined in the appended claims.

The invention is thus not to be considered limited to the above-mentioned embodiments but can be varied within the scope specified by the appended claims.

Claims (5)

10 15 20 25 30 534 146 lb PATENT REQUIREMENTS A braking device (100) for braking a motor vehicle (10) provided with a driveline (20) comprising a motor (30) for driving the vehicle, a gearing device (40) connected to the engine arranged to provide different gear ratios, and drive wheels (82, 84 ), wherein the shifting device comprises a main gearbox (42) with a main shaft (43) and a range shifting device (50) including an input shaft (52) to which driving force is arranged to be transmitted from the main shaft (43) and an output (54), switchable between a high-range area, where the output shaft (54) is arranged to rotate at speeds corresponding to a certain gear ratio, and a low-range area, where the shaft which range gear device is the output shaft (54) is arranged to rotate at a lower speed corresponding to a certain lower gear ratio relative the input shaft (52), the output shaft being arranged to transmit driving force to the drive wheels (82, 84), the braking device (100) being connected to the drive line (20) so that the brake The drive wheels (82, 84) are allowed for braking the motor vehicle, the braking device (100) being arranged to rotate by acting on the input shaft (52), characterized in that the rotation of the braking device (100) is intended to be effected by means of a direct connection with said input shaft. (52). braking action of the gearshift device (50) Braking device according to claim 1, wherein the braking device (100) is a retarder device (100), for example a hydraulic retarder device or an electromagnetic retarder device. A method of braking a motor vehicle (10) provided with a driveline (20) comprising a motor (30) for driving the vehicle, a shifting device (40) connected to the engine arranged to provide different gear ratios, and drive wheels (82, 84), wherein the shifting device comprises a main gearbox (42) having a main shaft including an input shaft (52) to which driving force is transmitted from (43) and a gear shifting device (50) the main shaft (43) and an output shaft (54), the gear shifting device being 534 146 in? interchangeable between a high-range range, the output shaft (54) rotating at a speed corresponding to a certain gear ratio, and a low-range range, the output shaft (54) rotating at a lower speed corresponding to a certain lower gear ratio relative to the input shaft (52), the the output shaft (54) transmits driving force to the drive wheels (82, 84), comprising the step of braking the drive wheels (82, 84) via the driveline (20) for braking the motor vehicle, by exerting the braking action on the input shaft (52) of the range (50) of the step of exerting said braking action directly on the input shaft (52). A method according to claim 3, wherein the step of exerting said braking action is effected by means of a retarder device (100), for example a hydraulic retarder device or an electromagnetic retarder device. Motor vehicle comprising a device according to any one of claims 1-2.