CN107795610B

CN107795610B - Multi-disc brake

Info

Publication number: CN107795610B
Application number: CN201710751382.5A
Authority: CN
Inventors: C·施坦贝格尔
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2016-08-30
Filing date: 2017-08-28
Publication date: 2020-10-30
Anticipated expiration: 2037-08-28
Also published as: DE102016216300A1; CN107795610A

Abstract

The invention relates to a multi-disc brake, which is provided with a first friction plate set assembly and a second friction plate set assembly which are coaxial with each other, wherein the first friction plate set assembly consists of a first outer friction plate set and a first inner friction plate set connected with a first shaft, and the second friction plate set assembly consists of a second outer friction plate set and a second friction plate set connected with a second shaft. A radial supply channel is formed in at least one component of an actuator of the multi-disc brake, through which a cooling fluid can be supplied to a radially outer end of the radial supply channel, and the radially inner end of which is connected to at least one outlet channel, which opens into a first and/or a second coaxial bore in the first shaft and in the second shaft, and one or more radial outlet channels are formed in the first shaft and in the second shaft, which outlet channels lead from the first coaxial bore to the first inner disk set and from the second coaxial bore to the second inner disk set.

Description

Multi-disc brake

Technical Field

The invention relates to a multi-disc brake, comprising: a first and a second friction plate set assembly coaxial to each other, the first friction plate set assembly being composed of a first outer friction plate set which is non-rotatable and axially movable and a first inner friction plate set which is non-rotatably connected to a first shaft which is rotatably driven and axially movable, the second friction plate set assembly being composed of a second outer friction plate set which is non-rotatable and axially movable and a second friction plate set which is coaxial to the first shaft and rotatably driven and axially movable and connected to a second shaft which is non-rotatably connected to the first shaft, wherein the first and the second friction plate set assemblies are surrounded by a common housing; an actuator axially arranged between the first and second friction disc set assemblies and axially loadable by the actuator a first inner and a first outer friction disc set and a second inner and a second outer friction disc set of the friction disc set assemblies; cooling means by which a cooling fluid flow is guided radially inwardly through the friction plate pack assembly.

Background

In known multi-disk brakes of this type with only one friction disk pack assembly, the cooling fluid flow is conveyed coaxially through the shaft and then radially outward to the friction disks. At this point, the cooling fluid flow continues to be conveyed and thrown radially outward. Such a transport of the cooling fluid flow cannot be achieved in two coaxial shafts that are separated from each other.

Disclosure of Invention

The object of the invention is to provide a multi-disk brake of the type mentioned at the beginning which avoids the disadvantages mentioned and ensures good heat dissipation when two coaxial shafts are present.

According to the invention, this object is achieved in that a radial feed channel is formed in at least one component of the actuator, a cooling fluid can be fed to a radially outer end of the radial feed channel via a radial feed line, and a radially inner end of the feed channel is connected to at least one outlet line, which opens into a first and/or a second coaxial bore in the first shaft and the second shaft, wherein one or more radial outlet channels are formed in the first shaft and in the second shaft, which radial outlet channels lead from the first coaxial bore to the first inner disk set and from the second coaxial bore to the second inner disk set.

In other words, two multi-disk brakes can be arranged in a space-saving and common cooling manner. Likewise, the arrangement of the actuators axially between the friction plate pack assemblies results in a compact construction solution requiring a small amount of installation space.

With this arrangement, the cooling fluid can be axially supplied to the coaxial bores of each shaft and can pass through the radial outflow channels to the friction points of the friction disk pack. Due to the grooves in the friction linings of the friction linings and the air gap between the friction linings, the cooling fluid can be conveyed and thrown radially outward. Here, the cooling fluid ensures the required lubrication of the friction linings and absorbs heat.

In the housing, a cooling fluid sump can be arranged radially below the friction disk pack, which has a cooling fluid outlet, through which cooling fluid can be tapped.

Since the disk set does not have to be sunk into the oil sump, drag losses of the disk set are reduced in the open state of the multi-disk brake. The cooling fluid can then be removed from the multi-disk brake and cooled externally before it is fed back to the cooling circuit. This form of cooling is effective.

The actuator is preferably a ball ramp actuator, which has two actuation disks arranged coaxially next to one another, which can be moved axially away from one another by an actuating device, wherein one or more radial feed channels are formed in one or both of the actuation disks.

The use of a ball ramp actuator enables an axially space-saving design.

A simple distribution of the cooling fluid flow arriving via the supply channel into the two coaxial bores of the shaft is achieved in that the outlet line is T-shaped and the side branches of the "T" each project into a coaxial bore.

A simple construction and a simple assembly result when the outlet line is inserted fixedly with its radially outwardly directed end into a radial feed channel in a component of the actuator.

The feed line can completely overlap the radially outer end of the radial feed channel in each operating position of a component of the actuator.

However, depending on the operating position of the components of the actuator, the supply line can also overlap completely or partially with the radially outer end of the radial supply channel, so that the cooling fluid flow can be adjusted to the cooling demand.

The cooling fluid discharge can be connected to a feed line of the cooling device via a discharge line, wherein the discharge line can be connected to a suction connection of the cooling fluid pump and a pressure connection of the cooling fluid pump can be connected to the feed line of the cooling device.

If a cooling fluid cooler is arranged in the outlet line or in the supply line, efficient external cooling of the cooling fluid is provided before the cooling fluid is supplied to the multi-disk brake again.

The friction disks can be lubricated and cooled as required by adjusting the supply flow of the cooling fluid pump.

The position of the control disks of the ball ramp actuator and/or the temperature of the cooling fluid can be detected by the sensor device, and the cooling fluid pump can be controlled accordingly in such a way that a higher cooling fluid flow is supplied when the control disks are at a greater distance from one another and/or when the temperature of the cooling fluid is higher, and a lower cooling fluid flow is supplied when the control disks are at a lesser distance from one another and/or when the temperature of the cooling fluid is lower.

Drawings

Embodiments of the invention are illustrated in the drawings and described in detail below. Wherein

Figure 1 shows a multi-disc brake and its construction environment,

figure 2 shows a cross-sectional view of the multi-disc brake according to figure 1,

figure 3 shows a longitudinal section through the multi-disc brake according to figure 1,

figure 4 shows a perspective view of the ball ramp actuator of the multi-disc brake according to figure 1 and its positive-acting actuating part in the ventilating position,

figure 5 shows a perspective view of the ball ramp actuator of the multi-disc brake according to figure 1 and its positive-acting actuating part in the braking position,

fig. 6 shows a perspective view of a friction lining of the multi-disc brake according to fig. 1.

Detailed Description

Fig. 1 shows an electric drive mechanism for a forklift. The drive mechanism is composed of a left side transmission 1, a right side transmission 2, a left side motor 3, a right side motor 4 and a multi-disc brake 5.

Fig. 2 and 3 show a multi-disc brake 5 and its construction environment. The housing of the left-hand transmission 1 is connected to the housing 15 of the left-hand electric motor 3. The housing of the right-hand transmission 2 is connected to the housing 16 of the right-hand electric motor 4. The

housings

15 and 16 of the electric motors 3 and 4 are fixedly connected to each other on the sides remote from the transmissions 1 and 2, respectively. The housing 15 of the left-hand electric motor 3 accommodates the multi-disc brake 5. The multi-disc brake 5 itself consists of a first friction disc pack assembly 6, a second friction disc pack assembly 7, a ball ramp actuator 8, a positively acting actuating part 9 and a negatively acting actuating part 10. The friction plate pack assemblies 6 and 7 consist of a friction plate lining 11 forming an inner shaft pack and a steel friction plate 12 forming an outer friction plate pack. The friction lining 11 of the first friction disk pack 6 is connected to a first shaft 13 of the left electric motor 3 in a rotationally fixed but axially displaceable manner. Steel friction plates 12 of first friction plate pack assembly 6 are connected to a housing 15 of left electric motor 3 in a rotationally fixed but axially displaceable manner. Friction lining 11 of second friction-disc pack assembly 7 is connected in a rotationally fixed but axially displaceable manner to a second shaft 14 of electric motor 4 on the right. Steel friction plates 12 of second friction plate pack assembly 7 are connected to the housing of left electric motor 3 in a rotationally fixed but axially displaceable manner. Friction lining surfaces 11 are arranged in friction plate pack assemblies 6 and 7 in such a way that one steel friction plate 12 is located on each of the left and right sides of each friction lining surface 11.

The ball ramp actuator 8 is located between the first and second friction plate set assemblies 6 and 7. In the case of travel drives for fork trucks, the axial installation space is limited, since the vehicle must be designed to be relatively narrow. The use of the ball ramp actuator 8 enables a space-saving design in the axial direction. The positive-acting actuating part 9 and the negative-acting actuating part 10 can thereby be arranged in the radial direction. The required installation space in the axial direction can thereby be minimized. Furthermore, with this arrangement, the positive-acting actuating part 9 and the negative-acting actuating part 10 are well accessible. Thereby, the assembly of the drive mechanism, the mounting of the drive mechanism into the vehicle and the maintenance of the operating section are simple.

Furthermore, variants of the actuating

sections

9 and 10 can be assembled very simply for different customer requirements of the drive mechanism, without having to change other components of the drive mechanism.

The ball ramp actuator 8 and its active actuating part 9 are shown in fig. 4 (brake ventilation) and fig. 5 (brake actuated). The ball ramp actuator 8 consists of two identical control disks 17, 17', at least three balls 18, a tension spring 19 and a pin 20. Between the two control wheels 17, the ball 18 is located in a wedge-shaped track 21. The tension spring 19 holds the control disks 17, 17' together under pretension.

The pins 20 are arranged in the control disks 17, 17 'in such a way that the control disks 17, 17' are rotated relative to one another when the wedge blocks 22 and 23 of the positive-acting actuating part 9 and the negative-acting actuating part 10 are pressed between the pins 20 by means of an inwardly directed

force

24 or 25. Due to the balls 18 running in the wedge-shaped running rails 21, the axial distance of the steering wheels 17, 17' also increases when they are rotated relative to one another. Thus, the air gap of the friction plate pack assemblies 6 and 7 is overcome and an axial force is exerted on the friction plate pack assemblies 6 and 7. On the engine side, the first friction-disc pack 6 is supported in the axial direction on a housing 15 of the left-hand electric motor 3, and the second friction-disc pack 7 is supported in the axial direction on a housing 16 of the right-hand electric motor 4. The friction-disc packs 6 and 7 can thus generate a braking torque which acts on the

shafts

13 and 14 of the electric motors 3 and 4, respectively.

If the

forces

24 and 25 no longer act on the wedge shoes 22 and 23, the tensioning of the tension spring 19 is used to take up the actuating disks 17, 17' again in their initial position and release the friction plate pack assemblies 6 and 7.

The positive-acting actuating part 9 is preferably used for service braking. If hydraulic pressure is applied, the ball ramp actuator 8 and thus the multi-disk brake 5 are actuated.

The negative-acting actuating part 10 is preferably used for emergency braking and parking braking functions. If hydraulic pressure is present, the multi-disc brake 5 is vented, and if no pressure is present, the multi-disc brake 5 is closed.

The multi-disc brake 5 has an active cooling for the friction-disc pack assemblies 6 and 7. The cooling means comprise a cooling circuit 26, which in this embodiment consists of a simple tube. The external cooling line 26 is fixed in the housing 15 of the electric motor 3 accommodating the brake 5 and enables a cooling fluid flow 29 to be supplied from outside the multi-disc brake 5. The cooling fluid flow 29 may be provided, for example, by an external cooling fluid pump, not shown. Furthermore, an internal oil delivery is required. For example, it is implemented as a T-shaped tube 30. The T-shaped tube 30 is fixedly inserted into a transport channel 31 in the control panel 17.

The inlet 33 of the T-shaped pipe 30 is arranged such that it can receive the cooling fluid flow 29 from the outlet 32 of the cooling circuit 26.

Since the control disk 17 is moved relative to the external cooling line 26 during the actuation of the multi-disk brake 5, a groove is formed at the outlet 32 of the feed channel 31 at the opening in the control disk 17, which groove is designed in such a way that the cooling fluid flow 29 is constant regardless of the position of the control disk 17. However, it is also possible to configure the slots in such a way that the cooling fluid flow 29 can be varied depending on the position of the control disk 17. The cooling fluid flow 29 branches off in the T-shaped pipe 30 and leaves the T-shaped pipe 30 at its output 34, 34'. The output 34, 34 'of the T-shaped tube 30 is located in coaxial bores 35, 35' of the

shafts

13 and 14.

Due to the rotary movement of the

shafts

13 and 14 about the axis of rotation 37, the cooling fluid flow 29 conveyed through the T-shaped pipe 30 and exiting from its outlet 34, 34 'is conveyed radially outward through the radial outflow channels 36, 36' introduced into the

shafts

13 and 14 and conveyed to the friction plate package 6 and 7. Here, the cooling fluid serves as a lubricant and coolant.

The radial outflow channels 36, 36' are arranged in such a way that substantially all of the friction lining surfaces 11 are supplied with cooling fluid. When the friction plate pack assemblies 6 and 7 are closed, the cooling fluid can flow radially out through the facing grooves 38 of the friction plate linings 11. Here, the cooling fluid absorbs the frictional heat generated in the friction plate pack assemblies 6 and 7.

The cooling fluid then collects in the cooling fluid sump 28 and can be removed at the cooling fluid outlet 27 of the multi-disk brake 5. The cooling fluid can be cooled externally and then fed back to the circuit.

The friction lining 11 is shown in fig. 6.

The advantages of the multi-disc brake according to the invention are:

active lubrication and cooling of a multi-disk brake enables a targeted cooling fluid flow for optimal lubrication and heat removal. The cooling fluid flow can be influenced purposefully as desired. Particularly much heat can be generated when the multi-disc brake is closed. In this case, a high cooling fluid flow can be provided, which ensures good lubrication and heat removal.

When the multi-disk brake is open, a low drag torque of the multi-disk brake is of primary importance. The cooling fluid flow may be reduced to minimize losses in the multi-disc brake. Depending on the return temperature of the cooling fluid, the cooling fluid flow can be regulated independently of the operating state of the multi-disk brake, so that the multi-disk brake always operates within the permissible temperature range. Furthermore, thermal power can be dissipated by means of an external cooling fluid cooler.

The friction plate pack does not have to be in continuous contact with the cooling fluid in the cooling fluid sump, since the cooling fluid can be continuously supplied. Thereby, drag loss can be reduced in the state where the friction plate group is opened. In this case, the lubrication can only be influenced by the oil level.

List of reference numerals:

1 left side transmission

2 right side transmission

3 left side motor

4 right side motor

5 multi-disc brake

6 first friction plate group component

7 second friction plate group component

8 ball type slope actuator

9 positive operation part

10 negative control part

11 friction lining

12 steel friction plate

13 first shaft

14 second shaft

15 case, left side motor

16-case right-side motor

17 control panel

17' steering wheel

18 ball

19 tension spring

20 pin

21 track

22 wedge-shaped block

23 wedge-shaped block

24 force, directed inwards

25 force, pointing outwards

26 cooling circuit

27 discharge part of cooling fluid

28 cooling fluid sump

29 flow of cooling fluid

30T-shaped tube

31 conveyance path

32 output part

33 input unit

34 output part

34' output part

35 coaxial hole

35' coaxial hole

36 outflow channel

36' outflow channel

37 axis of rotation

38 facing groove

Claims

1. A multi-disc brake having: a first and a second friction plate set assembly (6, 7) which are coaxial to each other, the first friction plate set assembly (6) being composed of a first, rotationally fixed, axially displaceable outer friction plate set and a first, rotationally fixed, axially displaceable inner friction plate set connected to a first rotationally drivable shaft (13), the second friction plate set assembly (7) being composed of a second, rotationally fixed, axially displaceable outer friction plate set and an axially displaceable second, rotationally fixed, inner friction plate set connected to a second, rotationally drivable shaft (14) which is coaxial to the first shaft (13), wherein the first and the second friction plate set assembly (6, 7) are enclosed by a common housing (15, 16); an actuator arranged axially between the first and second friction disc set assemblies (6, 7) and axially loadable by the actuator with a first and a second inner and a second outer friction disc set of the friction disc set assemblies (6, 7); cooling device, by means of which a cooling fluid flow can be conducted radially from the inside through the set of friction plates (6, 7), characterized in that a radial feed channel (31) is formed in at least one component of the actuator, that a cooling fluid can be fed to a radially outer end of the radial feed channel (31) via a radial feed line (26), and that a radially inner end of the radial feed channel (31) is connected to at least one outlet line, which opens into a first and/or a second coaxial bore (35, 35') in the first shaft (13) and in the second shaft (14), wherein one or more radial outlet channels (36, 36') are formed in the first shaft (13) and in the second shaft (14), from which first coaxial bore (35) the radial outlet channels (36, 36') lead to the first set of inner friction plates and from the second coaxial bore (35') Leading to the second inner friction disc pack.

2. Multi-disc brake according to claim 1, characterized in that a cooling fluid bottom shell (28) is arranged in the housing (15, 16) radially below the set of friction discs, which cooling fluid bottom shell has a cooling fluid outlet (27), through which cooling fluid outlet (27) cooling fluid can be conducted.

3. The multi-disc brake according to claim 1, characterized in that the actuator is a ball ramp actuator (8) having two operating discs (17, 17') arranged coaxially side by side, which operating discs (17, 17') can be moved axially away from one another by an operating device, wherein one or more of the radial feed channels (31) are formed in one or both operating discs (17, 17 ').

4. A multi-disc brake according to any one of claims 1 to 3, characterized in that the outlet conduit is configured as a T (30) and the side branches of the "T" each project into one coaxial bore (35, 35').

5. A multi-disc brake according to any one of claims 1 to 3, characterized in that the outlet line is inserted with its radially outwardly directed end into a radial feed channel (31) in a component of the actuator.

6. A multi-disc brake according to any one of claims 1 to 3, characterized in that the delivery duct (26) completely overlaps the radially outer end of the radial delivery channel (31) in each operating position of a component of the actuator.

7. A multi-disc brake according to any one of claims 1 to 3, characterized in that the delivery duct (26) overlaps completely or partially with a radially outer end of the radial delivery channel (31) depending on the working position of the members of the actuator.

8. Multi-disc brake according to claim 2, characterized in that the cooling fluid discharge (27) is connected with the delivery line of the cooling device by a discharge line.

9. Multi-disc brake according to claim 8, characterized in that the discharge line is connected with a suction connection of a cooling fluid pump and a pressure connection of the cooling fluid pump is connected with a delivery line (26) of the cooling device.

10. Multi-disc brake according to claim 8, characterized in that a cooling fluid cooler is arranged in the discharge line or in the delivery line (26).

11. A multi-disc brake according to claim 9, characterised in that the supply flow of the cooling fluid pump is adjustable.