WO1999052755A1

WO1999052755A1 - Hydraulic retarder

Info

Publication number: WO1999052755A1
Application number: PCT/EP1999/002427
Authority: WO
Inventors: Pablo Carballo Rodriquez; Luis Millan Derqui
Original assignee: Kloft, Lothar
Priority date: 1998-04-10
Filing date: 1999-04-09
Publication date: 1999-10-21
Also published as: DE19816101C2; EP0988198A1; DE19816101A1

Abstract

The invention relates to a retarder (10), comprising a stator (12) and a rotor (14) which is rotationally mounted in said stator. The rotor (14) is coupled with the units (16) to be retarded, e.g. the drive train, gear shaft, motor shaft or similar. The retarder (10) is configured as a hydraulic retarder with a positive displacement circulation pump (18) with at least one pump chamber (20, 22). A controlled or regulated pressure valve (24) is allocated to said positive displacement circulation pump (18) on the delivery side. The retarder (10) is used preferably as an additional braking device, especially for vehicles such as heavy goods vehicles, automobiles or similar.

Description

Description: Hydraulic retarder

description

The invention relates to a retarder, preferably for use as an additional braking device, in particular for a vehicle, such as a truck, car or the like, with a stator and a rotor rotatably mounted in the stator, the rotor with the units to be braked, such as the drive train, gearbox, or motor shaft or the like is coupled.

Retarders of this type are already generally known. In general, these retarders are based on the principle of eddy current braking of the rotor, which is rotatably mounted between the magnet coils of a stator. Such retarders are described for example in DE 39 08 234 AI. These known retarders have proven themselves quite well in practice. However, the known retarders, which are based on the principle of eddy current braking, are also quite complex in terms of the structure and control of the retarder braking power.

The invention is based on the object of developing retarders of the type mentioned in such a way that the retarder is simple in construction and can be assembled quickly and inexpensively, at the same time ensuring high reliability and simple control of the retarder performance.

This object is achieved according to the invention in the retarder with the features mentioned at the outset essentially in that the retarder is designed as a hydraulic retarder with a circulation displacement pump with at least one pump chamber and the circulation displacement pump is assigned a controlled or regulated pressure valve on the pressure side. The retarder is therefore hydraulic

βESWIGUNGSKOPIE Circulation displacement pump is formed, in which the rotor is coupled to the drive train or the like of the unit to be braked. The power to be output by the hydraulic pump or the braking force or braking torque are determined by the respective setting of the controlled or regulated pressure valve. Ultimately, the braking torque of this retarder is determined by the power demanded by the circulating displacement pump. This performance in turn depends on the setting of the controlled or regulated pressure valve. The energy released when the rotor is braked is converted into thermal energy, which leads to an increase in the temperature of the fluid. This construction of the retarder according to the invention means that the use of magnetic field generating elements, such as coils or the like, and the associated control or regulating power electronics can be dispensed with entirely. The retarder according to the invention is also simple and compact and light, for example it can be installed or retrofitted in the vehicle. To this extent, the retarder is used in particular as an additional braking device, for example in trucks, heavy industrial vehicles or the like.

According to a first advantageous embodiment of the invention, the circulating displacement pump is designed as a gear pump with internal or external toothing, screw pump, vane pump, such as a single-stroke or multi-stroke driving vane pump or preferably as a blocking vane pump. Pumps of this type are described, for example, in Dubbel, Taschenbuch für den Maschinenbau, 18th edition, ISBN 3-540-57650-9 in the chapter fluidic drives, which is expressly included in the disclosure content of the present application.

According to an extremely advantageous embodiment of the invention, the circulation displacement pump is designed as a blocking slide pump, the stator being essentially one circular cylindrical inner wall and the rotor has at least one electrical or oval or other non-circular outer wall with in particular 180 ° rotational symmetry and the inner diameter of the inner wall corresponds essentially to a large semiaxis or the maximum diameter of the outer wall. For example, the rotor can also be designed as a double cam rotor or the like.

Of particular advantage, the blocking slide pump has n pumping chambers with n = 2, 3, 4, with each pumping chamber being assigned a rotor section, each with in particular an elliptical or similar outer wall, in particular with 180 ° rotational symmetry. The large semiaxes and the maximum diameter of the rotor sections are offset by 180 ° / n. Because at least two pumping chambers are provided with rotor sections offset by 90 ° in this case, extremely continuous output or continuous braking torque is achieved via a 360 "rotation of the rotor. Under certain circumstances, this continuous output of the circulating displacement pump can be further improved that more than two pumping chambers are provided with the corresponding number of rotor sections It is understood that the individual pumping chambers are separated from one another by partitions or the like.

The measure that the blocking slide pump is designed as a double-chamber pump proves to be particularly advantageous. This ensures a very simple mechanical construction, the power output of the blocking slide pump or the braking torque generated by the blocking slide pump being quite uniform or continuous.

According to another advantageous embodiment of the invention, each pumping chamber is assigned two gate valves, which in the stator is radially displaceable and are arranged essentially diametrically to one another per pump chamber. Because of this measure, two pressure chamber and two suction chamber regions are formed for each pump chamber, which improves the performance of the gate valve pump.

The locking slides are subjected to an outward bias acting against the direction of the rotor axis, for example by a compression spring or the like. This measure ensures that, due to the action of the associated compression springs, the locking slides are initially positioned in an opening position in which the pressure chamber area is connected to the suction chamber area.

As an extremely advantageous independent embodiment of the invention, it is provided that the locking slide can be moved from the locking position into an open position and vice versa by means of a control device. It is thus possible that the braking torque of the retarder can be suddenly reduced to zero by moving the locking slide from the locking position into an open position. If the blocking slides are primarily moved radially outwards from the contact position on the rotor or the rotor sections, they are

Pressure chamber areas directly connected to the corresponding suction chamber areas, so that the current setting of the pressure valve for the braking torque of the retarder does not matter. In this case, the rotor of the blocking slide pump rotates practically without resistance in the stator, so that no braking torque is exerted on the corresponding unit by the retarder. In principle, moving the locking slide into the open position is equivalent to opening the pressure valve completely, with the retarder due to the passage through the channels when the pressure valve is fully open and the locking slide is in the locked position or lines and the like caused flow resistance permanently exerts a small braking torque on the unit in question. This loss of performance can be excluded by moving the locking slide into the open position. In addition, the braking action of the retarder can be switched off very abruptly by moving the locking slide into the open position, while opening the pressure valve leads to a slowed down reduction in the braking power.

Each pumping chamber of the circulating displacement pump is advantageously assigned two blocking slides, whereby at least two pressure chamber and two suction chamber regions are formed in each pump chamber.

According to another development of the invention, all pressure chamber areas are at least indirectly connected to the inlet of the pressure valve via bores in the stator and connected fluid channels or lines.

Furthermore, all suction chamber areas are at least indirectly connected to the outlet of the pressure valve via bores in the stator and connected fluid channels or lines.

A heat exchanger and / or a fluid reservoir and / or a fluid filter are particularly advantageously connected in the fluid circuit between the pressure chamber area and the suction chamber area. The heat exchanger is used to dissipate the thermal energy which, due to the braking torque given off by the retarder, leads to heating of the fluid in the fluid circuit.

According to another preferred embodiment, the heat exchanger is connected to a cooling circuit, wherein this cooling circuit is in particular part of the brake engine of the motor vehicle.

The control device for the locking slide is actuated according to a preferred embodiment of the invention by means of a solenoid valve, for example via compressed air.

The pressure valve itself is preferably designed as an electromagnetically controlled pressure control valve.

The retarder has an electronic control for controlling or regulating the braking power, to which one or more of the parameters vehicle speed, pressure of the pumping fluid, temperature of the pumping fluid, manual start / stop signal or manual or programmed braking power preselection are supplied as an input variable.

The output variables of the control are used to control or regulate the pressure valve and / or to actuate the control device of the gate valve or the like.

Further objectives, advantages, features and possible uses of the present invention result from the following description of exemplary embodiments with reference to the drawings. All of the described and / or illustrated features, alone or in any meaningful combination, form the subject matter of the present invention, regardless of how they are summarized in the claims or their relationship.

Show it:

FIG. 1 shows a side view of an exemplary embodiment of the retarder according to the invention in a basic illustration, partly in section, FIG. 2 shows a schematic representation of a top view of the retarder in the direction of the rotor axis to explain the configuration and arrangement of the rotor sections,

FIG. 3 shows a section of the retarder in a sectional view in the area of a locking slide to explain the position of the pressure chamber and suction chamber areas,

Figure 4 is a schematic representation of an overall view of the retarder with associated fluid circuit and additional components and

Figure 5 shows a schematic representation of the control of the retarder according to the invention with different input and output variables.

The retarder 10 shown in the figures is preferably used as an additional braking device in motor vehicles, such as trucks, cars or the like. The retarder 10 has a stator 12 and a rotor 14 which is rotatably mounted in the stator 12, the rotor 14 being coupled to the units 16 to be braked, such as a drive train, a cardan shaft or other shaft.

The retarder 10 is designed as a hydraulic retarder 10 with a circulation displacement pump 18 with at least one pump chamber 20, 22. The circulating displacement pump 18 is assigned a controlled or regulated pressure valve 24 on the pressure side. The circulating displacement pump 18 can be a gear pump with internal or external toothing, screw pump, vane pump, such as a single-stroke or multi-stroke driving vane pump, preferably also a blocking vane pump 26. If the circulating displacement pump 18 is designed as a blocking slide pump 26, the stator 12 has an essentially circular cylindrical inner wall 28. The rotor 14 has at least one elliptical, oval or other non-circular outer wall 30, 32 with in particular 180 ° rotational symmetry. The inner diameter of the inner wall 28 is essentially identical to a large semi-axis or the maximum diameter of the outer wall 30, 32.

The blocking slide pump 26 has two pumping chambers 20, 22, with each pumping chamber 20, 22 being assigned a rotor section 34, 36, each with an elliptical outer wall 30, 32 and 180 ° rotational symmetry.

The large semiaxes or the maximum diameters of the rotor sections 34, 36 are offset from one another by 90 °.

Each pump chamber 20, 22 is assigned two locking slides 38, 40, 42, 44, which are mounted in the housing of the stator 12 so as to be radially displaceable and are arranged essentially diametrically to one another per pump chamber 20, 22. The locking slides 38 to 44 are acted upon, for example, by a compression spring 46, 48 with a prestress acting in the direction of the rotor axis 50. Furthermore, a control device 52, 54 is assigned to each of the locking slides 38 to 44, with which the locking slide 38 to 44 can be moved from a locking position into an open position and vice versa.

Each pump chamber 20, 22 of the circulation displacement pump 18 has at least two pressure chamber regions 56 and suction chamber region 58. All pressure chamber areas 56 are at least indirectly connected to the inlet 64 of the pressure valve 24 via bores 60 in the housing of the stator 12 and connected fluid channels 62 or fluid lines. Everyone too Suction chamber areas 58 are indirectly connected to the outlet 70 of the pressure valve 24 via bores 66 in the housing of the stator 12 and connected fluid channels 68 or fluid lines.

A heat exchanger 74, a fluid reservoir 76 and a fluid filter 78 are connected in the fluid circuit 72 between the pressure chamber region 56 and the suction chamber region 58. The heat exchanger 74 is preferably connected to a cooling circuit 80, for example the internal combustion engine of the motor vehicle.

The control device 52, 54 for the locking slide 38 to 44 is actuated by means of a magnetic air valve via lines 92 carrying compressed air. The pressure valve 24 is designed as an electromagnetically controlled pressure control valve.

Furthermore, an electronic controller 80 is provided for controlling or regulating the braking power of the retarder 10, to which the parameters vehicle speed 84, pressure of the pump fluid 86, temperature of the pump fluid 88, manual start / stop signal 90 of the manual or programmed braking power preselection are supplied as input variables. The output variables of the controller 80 are used to control or regulate the pressure valve 24 and / or to actuate the control device 52, 54 of the locking slides 38 to 44.

It should be mentioned that the rotor 14 is mounted in the housing of the stator 12 by means of a bearing 94 and bearing rings 96. The rotor 14 is seated on a shaft 98, which in turn is coupled to the unit 16. A seal 100 is provided between the shaft 98 and the housing of the stator 12.

The following basic elements of the exemplary embodiment are of particular importance: 10

The rotor 14 has two rotor sections 23, 36, which are essentially elliptical and are arranged offset by 90 ° to one another. Due to this measure, a more uniform braking torque is generated by rotating the rotor 14 through 360 °. In other words, this means that these measures achieve a delivery volume of the blocking slide pump 26 which is proportional to the speed or the angle of rotation of the rotor 14.

The stator 12 is cylindrical and has an inner diameter which, taking manufacturing tolerances into account, corresponds to the maximum outer diameter of the rotor 14. Integrated in the stator 12 are the bores 60, 66, the locking slides 38 to 44 and possibly also the fluid channels 62, 68 and possibly the control device 52, 54, furthermore the pressure valve 24, the heat exchanger 74, the fluid reservoir 76 and the fluid filter 78 or the entire fluid circuit 72 may be arranged in the stator 12.

The locking slides 38 to 44 controlled by the control device 42, 54 rest in the locking position on the outer walls 30, 32 of the rotor 14 and thus ensure a separation of the pressure chamber region 56 and the suction chamber region 58. As a result, the fluid is forced out of the pressure chamber region 56 the bores 60 and the fluid channels 62 to flow to the inlet 64 of the pressure valve 24. Conversely, via the bores 66 and the fluid channels 68, the fluid from the outlet 70 of the pressure valve 24 is passed directly or indirectly to the suction chamber area 58. These locking slides are moved radially outward into an opening position by means of the control device 52, 44, provided that braking power is not required of the retarder, so that the fluid then moves directly from the pressure chamber area 56 into the stator 12 11

Suction chamber area 58 can flow. With the blocking slides 38 to 44 in the open position, the rotor 14 rotates in the stator 12 practically without resistance.

The pressure valve 24 determines the required braking power between the value zero and the maximum value. The braking torque is directly proportional to the fluid pressure, which can be adjusted by a corresponding control or regulation of the pressure valve 24.

The heat exchanger 74 ensures that the heat absorbed by the fluid due to the braking torque is dissipated via a cooling circuit, for example of the vehicle engine.

The fluid reservoir 76 can itself be integrated in the stator 12 or can also be arranged independently of the stator 12, for example in the region of the vehicle.

The electronic control 62 can, for example, receive information from the cabin of the vehicle that is based on various braking torque values or also the vehicle top speed. For example, the activity of the retarder 10 can start when a specific, predetermined maximum vehicle speed value is exceeded.

The retarder 10 works as follows:

When the vehicle equipped with such a retarder 10 travels, the locking slides 38 to 44 of the locking slide pump 26 are in the open position when the retarder 10 is switched off, since the control device 52, 54 is not activated and the locking slides 38, 44 due to the pretensioning of the compression springs 46 in the opening position has been transferred. If the control devices 52, 54 are now activated by compressed air 92 through the corresponding channels or lines into the chambers for the locking slides 31 to 44 12

is initiated, the locking slides 38, 44 are moved against the force of the compression springs 46, 48 radially in the direction of the rotor axis 50 into the locking position, in order then to lie sealingly on the outer wall 30, 32 of the rotor sections 34, 36.

When the gate valves 38 to 44 are in the open position, the pressure valve 24 is also fully opened, so that the fluid can escape from the pumping chambers 20, 22, for example due to its own centrifugal force, into the bores 60, 66 to fluid channels 62, 68. In this state, the rotor 14 rotates in the stator 12 practically without friction, the retarder 10 not developing any braking torque.

When the retarder 10 is activated, the chambers which hold the locking slides 38 to 44 are pressurized with compressed air, for example via a solenoid air valve, which ensures that the locking slides 38 to 44 counter to the action of the compression springs 46, 48 radially inwards in the direction of the rotor axis 50 can be moved and rest sealingly on the outer wall 30, 32 of the rotor sections 34, 36. As a result, the pump chambers 20, 22 of the blocking slide pump 26 are subdivided into said pressure chamber regions 56 and suction chamber regions 58, so that a pumping action for the fluid now takes place and the fluid is guided out of the bores 60 and fluid channels 62 to the inlet 64 of the pressure valve 24. On the other hand, the fluid is sucked into the suction chamber area 58 via the bores 66 and the fluid channels 68.

The envelope of the braking torque output by the retarder 10 is determined by the setting of the pressure valve 24, since the braking force or the braking torque is essentially proportional to the fluid pressure. A variation in the braking torque is ensured by a corresponding activation or regulation of the pressure valve 24. 13

The braking torque output by the retarder 10 is converted into heat, which heats the fluid flowing in the fluid circuit 72. To this extent, a heat exchanger 74 is provided in order to reduce the fluid temperature. The heat exchanger 74 can be connected to the engine cooling water circuit of the motor vehicle or to an independent circuit.

If one considers a single rotor section 34 of the rotor 14, the resistance torque or braking torque of the retarder 10, which is dependent on the angle of rotation, runs essentially sinusoidally between zero and a maximum value. These fluctuations in the braking torque are practically compensated for in that the second rotor section 36 is arranged offset by 90 ° with respect to the first rotor section 34, so that the sum of the two resistance moments or braking torques dependent on the angle of rotation is essentially constant over the entire angle of rotation of 360 ° is.

Small flow losses, which can occur between the stator 12 and the rotor, ensure that a small proportion of the fluid reaches the interior of the rotor 14 in the region of the shaft 98. The shaft is hermetically sealed due to corresponding bearings 94 or bearing rings 96 so that the fluid cannot escape to the outside. Due to the centrifugal forces acting in the interior of the rotor 14, the fluid that has reached there is collected in the area of the periphery and can be led back into the fluid reservoir 76 via a line. 14

Reference list

10 retarders

12 stator

14 rotor

16 - aggregate

18 circulation pump

20 pump chamber

22 pumping chamber

24 pressure valve

26 Gate valve pump

28 inner wall

30 - outer wall

32 - outer wall

34 - rotor section

36 rotor section

38 gate valve

40 gate valve

42 gate valve

44 gate valve

46 compression spring

48 compression spring

50 rotor axis

52 control device

54 control device

56 - pressure chamber area

58 suction chamber area

60 holes

62 fluid channels

64 - inlet

66 holes

68 fluid channels

70 outlet

72 fluid circuit

74 heat exchangers

76 fluid reservoir 15

78 - fluid filter

80 - cooling circuit

82 - electrical control

84 - speed

86 - Pump fluid pressure

88 - Pump fluid temperature

90 - manual signal

92 - compressed air

94 - warehouse

96 - bearing ring

98 - wave

100 - seal

Claims

16 patent claims

1. retarder (10), preferably for use as an additional braking device, in particular for a vehicle, such as a truck, car or the like, with a stator (12) and a rotor (14) rotatably mounted in the stator (12), the rotor ( 14) with the units to be braked (16), such as the drive train, transmission or motor shaft or the like, characterized in that the retarder (10) as a hydraulic retarder with a

Circulation displacement pump (18) is formed with at least one pump chamber (20, 22) and the circulation displacement pump (18) is assigned a controlled or regulated pressure valve (24) on the pressure side.

2. Retarder according to claim 1, characterized in that the circulating displacement pump (18) is a gear pump with internal or external toothing, a screw pump, vane pump, such as a single-stroke or multi-stroke driving vane pump or blocking vane pump (26).

3. Retarder according to one of the preceding claims, characterized in that the circulation displacement pump (18) is designed as a blocking slide pump (26), the stator (12) has a substantially circular cylindrical inner wall (28) and the rotor (14) has at least one electrical, oval or other non-round outer wall (30, 32) with in particular 180 ° rotational symmetry, the inner diameter of the inner wall (28) essentially corresponding to a large semi-axis or the maximum diameter of the outer wall (30, 32).

4. Retarder according to one of the preceding claims, characterized in that the blocking slide pump (26) has n- pumping chambers (20, 22) with n = 2, 3, 4 and each pumping chamber (20, 22) has a rotor section (34, 36) with each 17

in particular an elliptical or similar outer wall (30, 32) with in particular 180 ° rotational symmetry is assigned, the large semi-axes or the maximum diameter of the rotor sections (34, 36) being arranged offset from one another by 180 ° / n.

5. Retarder according to one of the preceding claims, characterized in that the locking slide pump (26) is designed as a double chamber pump.

6. Retarder according to one of the preceding claims, characterized in that each pump chamber (20, 22) is assigned two locking slides (38, 40, 42, 44) which are mounted in the stator (12) so as to be radially displaceable and per pump chamber (20, 22) are arranged essentially diametrically to one another.

7. Retarder according to one of the preceding claims, characterized in that the locking slide (38 to 44) with a radially outward, acting against the direction of the rotor axis bias, for example by a compression spring (46, 48) or the like.

8. Retarder according to one of the preceding claims, characterized in that the locking slide (38 to 44) by means of a control device (52, 54) can be moved from the locked position into an open position and vice versa.

9. Retarder according to one of the preceding claims, characterized in that each pump chamber (20, 22)

Circulation displacement pump (18) has at least two pressure chamber areas (56) and two suction chamber areas (58).

10. Retarder according to one of the preceding claims, characterized in that all pressure chamber areas (56) over 18th

Bores (60) in the stator (12) and connected fluid channels (62) or lines are at least indirectly connected to the inlet (64) of the pressure valve (24).

11. Retarder according to one of the preceding claims, characterized in that all suction chamber areas (58) via bores (66) in the stator (12) and connected fluid channels (68) or lines at least indirectly to the outlet (70) of the pressure valve (24) are connected.

12. Retarder according to one of the preceding claims, characterized in that in the fluid circuit (72) between the pressure chamber region (56) and suction chamber region (58) a heat exchanger (74) and / or a fluid reservoir (76) and / or a fluid filter (78) are switched.

13. Retarder according to claim 12, characterized in that the heat exchanger (74) is connected to a cooling circuit (80), for example the internal combustion engine of the motor vehicle.

14. Retarder according to one of claims 8 to 13, characterized in that the control device (52, 54) for the locking slide (38, 44) is actuated by means of a solenoid air valve via compressed air (92).

15. Retarder according to one of the preceding claims, characterized in that the pressure valve (24) is designed as an electromagnetically controlled pressure control valve.

16. Retarder according to one of the preceding claims, characterized in that an electronic control (80) for controlling or regulating the braking power of the retarder (0) is provided, which as input variables one or more of the parameters vehicle speed (84), pressure of the 19

Pump fluids (86), temperature of the pump fluid (88), manual start / stop signal (90) or manual or programmed braking power preselection.

17. Retarder according to claim 16, characterized in that the output variables of the electronic control (80) for controlling or regulating the pressure valve (24) and / or for actuating the control device (52, 54) of the locking slide (38 to 44) or the like are used become.