SE532821C2 - Braking device and method of braking - Google Patents

Abstract

The brake arrangement (100) has a drive train (20) with a motor (30) for driving the vehicle. A gear arrangement (40) is connected with the engine and is so designed that different gear transmission ratios are attained. The brake arrangement is designed such that it carries out a braking effect at an input shaft of a range-gear arrangement (50). An independent claim is included for a method for braking a motor vehicle.

Description

532 821 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 that is present in the space is regulated. Before the retarder begins to produce an output 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 retarder is more efficient at high speeds as the wheel brakes of, for example, a truck become hotter. However, a disadvantage of the secondary retarder is that the braking torque is 533 82% relatively poor at low speeds, which can be a problem when, for example, driving on serpentine roads downhill.

The braking torque / inclination 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 retardar vanes. 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 performance at low speeds and controllability and idle losses at high speeds. Larger retarders / blades result in larger components that take up more space, increase weight and also increase cost.

OBJECT 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.

SUMMARY OF THE INVENTION These and other objects, which appear from the following description, are achieved by means of a braking device and a motor vehicle as above, and which further have the features set forth in the characterizing part of appended claims 1 and 4, respectively. Preferred embodiments of the braking device are the dependent claims 2-3. According to the invention, the objects are achieved with a braking device for braking motor vehicles provided with a driveline comprising a motor for driving the vehicle, a shifting device connected to the engine arranged to provide different gear ratios, and drive wheels, the shifting device comprising a main gearbox and a gearbox an input shaft 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 region, the output shaft being arranged to rotate at speeds corresponding to a certain gear ratio, and a low-range region, where the output shaft is arranged to rotate at a lower speed corresponding to a certain lower gear ratio relative to the input shaft, 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 motor vehicles. wherein the braking device is a retarder device, for example a hydraulic retarder device or an electromagnetic device for exerting braking action on the input shaft of the range change device, the retarder device comprising a retarder and being 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.

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.

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. 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. 1 schematically shows a motor vehicle comprising master brakes arranged of the motor vehicle and an auxiliary braking device arranged 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 brake device arranged in connection with a range change 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 gear shifting 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, and Fig. 2 shows schematically the arrangement of an auxiliary brake device according to a variant of the present invention. According to fi g. 532 821 1, the vehicle 10 is provided with a driveline 20 which comprises a motor 30 for driving 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 driving wheels 82, 84.

As shown in fi g. 2 comprises main gearbox 42 with a main shaft 43 and a range shifter 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 switchable between a high range range, the output shaft 54 rotating at a speed corresponding to a certain gear ratio, normally the gear ratio 40 a relatively input shaft 52, and a low range range the output shaft 54 rotates at a lower speed corresponding to a certain lower gear ratio. relative to the input shaft 52. The output shaft 54 is arranged to transmit the driving force to the PTO shaft 60, 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 brake means 90e, 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. 532 825 of the range shifter 50 so that its gear is utilized.

Accordingly, the retarder device 100 is arranged in such a way that the braking torque produced by the braking action by means of 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 range. 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, which can be, for example, 3.75. The hydraulic retarder could have a gear ratio, for example 3.

When operating in the bearing range, due to the retarder device 100 being arranged to act on the input shaft 52 of the range changer 50 in this example, a gear which is the gear of the range changer 50, for example 3.75 multiplied by the gear of the retarder device 100, e.g. here the gear ratio of the range change device. As a result, a higher speed of the retarder device 100 is obtained, which results in a faster rise of the filling curve L for the low-range area relative to the curve H, as shown in Fig. 3, so that the desired plateau speeds / cardan shaft speeds. is reached already at very low Furthermore, it is possible to achieve a significantly higher braking torque thanks to the fact that as in this example there is a gear ratio on the retarder device 100. In the example according to Fig. 3 the torque is limited even for the low range, but since the power is relatively low at lower speeds / PTO shaft, it is possible to have 532 821 a higher braking torque when driving in the low-range area without this affecting the dimensioning of the retarder, as shown by the arrow A and the dashed alternative portion L 'of the fill curve L. By allowing the retarder 100 to form the shaft of the range also the retarder device 100 has a lower gear ratio compared to a secondary retarder and thus provide other advantages such as better controllability, uptake of space. act on the lower idle losses, and reduced the filling curve during operation in the low-range area, and consequently also during operation in the high-range area, can be affected by dimensioning the retarder device 100, ie. the vanes / vane device of the same, different, where larger vanes entail greater braking torque, and / or have different gears on the retarder device 100, ie. shifting device of the 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, here 3. operation in the high-range range 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 change device! the PTO shaft. This is shown in Fig. 3 of the filling 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. 532 821 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 preferably arranged between the stator 122 and the rotor 124 of the retarder 120. The space between stator122 and 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 range shifter 50 includes an input shaft 52, a shift configuration 56 and an output shaft 54. The input shaft 52 of the range 50 is the vehicle's main gearbox (not shown) received from the vehicle's engine (not shown). The output shaft 54 is arranged to transmit the power to the driving wheels of the vehicle via the gear configuration 56 of the gear shift device 50, preferably via the cardan shaft of the vehicle. This can be seen in Fig. 1. Arranged that via the gearshift configuration 56 it is arranged to either transfer 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 gear 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 attached to the input shaft 52, and depending on the gearbox type a number of planet wheels 59, for example three, four 532 821 or five planet wheels 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.

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 Fig. 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 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 take up space.

Fig. 5 schematically shows an auxiliary brake device 100 arranged in connection with a range change device according to a further embodiment of the present invention. The embodiment according to fi g. 5 is substantially the same as the embodiment according to fi g. 4 and differs from the embodiment of Fig. 4 only by the design of the retarder gear 110.

The retarder gear 110 according to the embodiment in fi g. 5 comprises a first gear 112 which is arranged to be supported on the input shaft 52 and rotated by 532 821 11 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 brought engaged with the first gear 112 so as to rotate by the first gear 112 upon actuation of the retarder device 100, and arranged to be engaged with the second gear 114 so as to rotate in the same direction relative to the input shaft 52. The retarder gear is arranged to by means of gearing transfer the rotation of the input shaft 52 to the retarder 120 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 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 fi g. 4, larger gears of the retarder gear are required to accomplish 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. 532 821 12 Because the retarder device 100 according to this embodiment is not provided with a retarder gear, it is dimensioned larger than the embodiment according to Figs. 4 and 5, in this variant. that it has a larger outer diameter, so that the blades are thus placed further away from the center of rotation, whereby higher braking torques are 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 embodiments above 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 shifting 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 the range change device with substantially 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.

Furthermore, other suitable media 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 device could also include a retarder gear without gear, which means that the retarder device can be placed on any 532 32 :! 13 position and yet rotated at the same rotational speed as the input shaft of the range change device.

The input shaft 52 of the range shifter 50 also includes the output shaft of 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.

Where quantities such as braking torques, effects and gears are these 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 should thus not be considered limited to the above embodiments but may be varied within its framework specified by the appended claims.

Claims (4)

10 15 20 25 532 821 14 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 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) 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 shaft (54), switchable between a high-range region, where the output shaft (54) is arranged to rotate at a speed corresponding to a certain gear ratio, and a low-range region, where the output shaft (54) is arranged to rotate at a lower speed corresponding to a certain lower gear ratio relative to 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 braking of the drive wheels (82, 84) with is provided for braking the motor vehicle, the braking device (100) being a retarder device (100), for example a hydraulic retarder device or an electromagnetic retarder device, which is arranged to exert a braking action on the input shaft (52) of the shift gear device (50), characterized in that the retarder device (100) ) comprises a retarder (120) and is arranged to exert said braking action via a shifting device (110) which enables the retarder (120) to be placed in a suitable place for reasons of space and not take up space between the main gearbox and the shifting device 100. which shifting device is Braking device according to claim 1, characterized in that the shifting device (110) comprises a first gear (112) which is arranged to be supported on the input shaft (52) and rotate with the input shaft, and a second gear (114) arranged to be supported on a retarder shaft (126) which rotates a rotor (124) included in the retarder. 532 821 15 Brake device according to claim 2, characterized by the gear device (110) comprising an intermediate gear (116) 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) when activating 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). Motor vehicle comprising a device according to any one of claims 1-3.