JPH06156216A - Fluid retarder - Google Patents

Abstract

PURPOSE:To prevent locking from occurring in a fluid retarder device for a motor truck and the like by installing in series a switching valve and a control valve which increases pressure in an air chamber side in a pipe according to increase in sprung weight at the pipe which connects a pressure air source to an air chamber in an air/fluid converter. CONSTITUTION:A switching valve 29 which selects a communication position with a retarder switch turned 312 on and a drainage position with the retarder switch 31 turned off is disposed at a pipe 30 which connects a pressure air source 4 with an air chamber 25d in an air/fluid converter 25. A control valve 28 is installed between a sprung part 32 and an unsprung part 33 of a vehicle, and pressure n the air chamber 25d side in the pipe 30 is controlled to increase according to an increase in sprung weight. With this constitution, it is thus possible to keep deceleration at a constant ratio regardless of a load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid type retarder device.

[0002]

2. Description of the Related Art A fluid type retarder device is provided in medium and large-sized vehicles such as trucks and buses, and generates a braking torque when descending a slope or decelerating from a high speed to increase the temperature of the friction braking device. To prevent vehicle fade and improve vehicle safety and friction material durability. As shown in FIG. 6, a conventional fluid type retarder device of this type includes a rotor that can be fixed to a rotating shaft that rotates together with wheels such as a propeller shaft, and a stator that is non-rotatably fixed to the vehicle body side. In the retarder 104, the rotor is connected and fixed to the rotary shaft side by the clutch device 106 driven by the drive device 108, the working liquid is agitated by the rotor, and friction loss of the working liquid and collision with the stator. Braking torque is generated by the loss.

However, in such a conventional fluid type retarder device, in order to increase / decrease the pressure of the working liquid to generate plural kinds of braking torques, different set pressures are set as shown in FIG. Multiple pressure reducing valves 10
0 and 101 are provided, the switching valve 102 is switched in conjunction with the switching operation of the retarder switch (not shown), and the pressure air from the pressure air source 105 is supplied to one pressure reducing valve 100.
Alternatively, the pressure is controlled to a predetermined pressure by 101, and the compressed air is supplied to the air-liquid conversion device 103 to generate a pressure liquid having a predetermined pressure in the working liquid cooler 109 or the fluid-type retarder 104, and a braking torque of different magnitude is generated. It was a structure to generate.

Therefore, not only the braking torque corresponding to the loaded weight of the vehicle cannot be properly generated, but also the setting pressure of the set pressure is set by the driver's erroneous switching operation of the retarder switch even when the vehicle is empty. There is a technical problem that an excessive braking torque may be generated by the high decompression valve 101, which may cause the wheels to be locked, which may be dangerous.

That is, the braking force applied to the rear wheels by the conventional fluid type retarder 104 is the pressure reducing valve 101 having a high set pressure.
When is selected, point A in FIG. 4 is inevitable. At this point A, the wheel skid limit at the time of maximum loading is equal to or less than the friction coefficient μ = 0.2 (shown in FIG. 4) with respect to the road surface of the wheel, and there is almost no possibility that the wheel will be locked, and an appropriate braking torque is generated. However, even when the friction coefficient μ is 0.9 (shown in FIG. 4) when the vehicle is empty, the wheels are locked. Therefore, when the vehicle is empty, the wheels lock on most of the road surface when the pressure reducing valve 101 with a high set pressure is selected. In addition, in FIG.
Reference numeral 07 denotes a switching valve, which drives the driving device 108 to connect or disconnect the clutch device 106 by the pressure air supplied from the pressure air source 105 via the switching valve 107 to connect the rotor and the rotating shaft of the fluid retarder 104. Connect or disconnect.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional technical problems, and the structure thereof is provided on a rotary shaft (10) which rotates with a wheel, and which is always operated liquid. And a fluid type retarder (1) having a rotor (16) and a non-rotating stator (15).
1), a clutch device (13) driven by a drive device (17) to connect or disconnect the rotor (16) and the rotating shaft (10), and a working liquid of the fluid retarder (11). A closed circuit (21) connecting between the inlet (11a) and the working liquid outlet (11b), an air-liquid conversion device (25) for applying air pressure to the working liquid in the closed circuit (21), and pressurized air. A fluid type retarder device comprising a source (4), wherein a retarder switch () is connected to a pipe (30) connecting the pressurized air source (4) and an air chamber (25d) of the air-liquid converter (25). The communication position (b) is taken by the ON operation of 31) and the drain position (a) is taken by the OFF operation of the retarder switch (31) to drain the air chamber (25d) of the air-liquid conversion device (25). A switching valve (29),
The pipe (3) is interposed between the sprung portion (32) and the unsprung portion (33) of the vehicle, and the pipe (3)
0) is a fluid type retarder device characterized by interposing in series a control valve (28) for controlling the pressure on the side of the air chamber (25d) to increase.

[Action]

When the retarder switch is switched to the ON position while the vehicle is traveling, the switching valve is switched from the drain position to the communication position by satisfying additional conditions such as an accelerator pedal OFF condition. As a result, the drive device is driven to connect the clutch device, and the rotor is integrally rotated with the rotary shaft.

On the other hand, when the switching valve takes the communicating position, the pressure air from the pressure air source reaches the control valve through the pipe. The control valve is interposed between the unsprung portion and the unsprung portion of the vehicle, and controls so that the pressure on the air chamber side in the pipe increases as the sprung weight increases, that is, the load increases. Have a function. As a result, when the load is comparatively small, the pressure of the working liquid of the closed circuit and the fluid type retarder is adjusted to a relatively small value in accordance with the comparatively low control pressure generated in the air chamber of the air-liquid converter, and the comparatively small value is obtained. Braking torque is generated.

When the load is relatively large,
In response to the relatively high control pressure generated in the air chamber of the air-liquid conversion device, the pressure of the working liquid in the closed circuit and the fluid retarder is adjusted to a high level, and a relatively large braking torque is generated. In this way, the braking torque generated by the hydraulic retarder continuously increases in accordance with the increase in the load.

The braking torque generated by the fluid retarder is caused by stirring of the rotor in a circulating state in which the working liquid that also serves as cooling flows in from the working liquid inlet and flows out from the working liquid outlet by the self-pumping action of the rotor. The kinetic energy-applied working liquid collides with the stator and is obtained while being transferred as heat to the working liquid.

If the retarder switch is turned off,
Since the switching valve returns to the drain position, the compressed air in the air chamber of the air-liquid conversion device is drained to the outside. In addition,
When the retarder switch is turned off, the clutch device is disengaged by the drive device to stop the rotation of the rotor. As a result, the braking torque due to the fluid retarder disappears.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show one embodiment of the present invention.
As shown in FIG. 1, the fluid retarder device includes a fluid retarder 11, a clutch device 13, a pneumatic cylinder device 17,
Air tank 4, which is the source of pressure air, cooler 2 for hydraulic fluid
3 and the air-liquid conversion device 25 are the main constituent elements.

As shown in FIG. 2, the fluid type retarder 11 is provided with a non-rotating case 11c fixed to a member on the vehicle body such as a transmission rear cover (not shown).
A rotary shaft 10, one end of which is connected to a transmission output shaft or the like, rotatably and liquid-tightly penetrates through the center of the shaft with an appropriate seal member and a bearing interposed. The other end of the rotating shaft 10 is connected to wheels via a propeller shaft (not shown) and rotates together with the wheels (rear wheels).

In this way, the retarder chamber 12 which is partitioned by the case 11c around the rotary shaft 10 and which is always filled with the working liquid (oil or water) is liquid-tightly defined. In the retarder chamber 12, a stator 15 having radial vanes centering on the rotary shaft 10 is provided, and also radial vanes centering on the rotary shaft 10 are provided to rotate facing the stator 15. A rotor 16 is provided on a member on the shaft 10 side so that the rotor 16 can be fixed so as not to rotate relative to the shaft 10. Stator 15
Is integrally formed with the case 11c and is fixed to the vehicle body-side member in a substantially non-rotatable manner.

Further, the case 11c includes a retarder chamber 12
A working liquid inlet 11a is provided at the center of
The working liquid outlet 11 is located at the outer peripheral portion of the retarder chamber 12.
b is provided.

Further, the rotating shaft 1 is provided on the inner peripheral portion of the rotor 16.
A wet multi-plate clutch device 13 capable of connecting or disconnecting the 0-side member and the rotor 16 is provided. The clutch device 13 is
A plurality of annular pressure plates 14 and a rotor 16 are fixed to the case 16, and the case 11c has a first bearing 13
A cylindrical support member 19 rotatably supported via a, which supports a suitable number of pressure plates 14 by spline coupling and supports slidably in the central axis direction, and a movable pressure plate 14 located at one end. And a second bearing 13b rotatably supported.

A pneumatic cylinder device 17, which is a drive device, is attached to the clutch device 13. The pneumatic cylinder device 17 includes a pressure chamber 17c defined by a diaphragm 17a, a diaphragm 17a, and a second bearing 13b.
The pressure chamber 17c is connected to the air tank 4 via a switching valve 29 described later. The plurality of clutch plates 18 are spline-coupled to the rotary shaft 10 so as to be movable in the axial direction, and are sandwiched between the pressure plates 14.

On the other hand, the working liquid inlet 11a provided in the case 11c is connected to the working liquid outlet 11b provided in the case 11c via the closed circuit 21 and the working liquid cooler 23. That is, the closed circuit 21 includes the working liquid inlet 11
A pump 22 and a working liquid cooler 23 that sequentially circulate the working liquid from the a side are connected. The pump 22 is
It is rotationally driven by the electric motor 22a, and the hydraulic fluid cooler 23 is air-cooled by the fan 23a.

Further, an empty liquid for exerting air pressure on a suitable portion of the closed circuit 21 (in the illustrated embodiment, one end portion of the working liquid cooler 23) to the working liquid of the closed circuit 21 and further of the hydraulic retarder 11. The converter 25 is connected via a pipe 38. The air-liquid conversion device 25 has an air-tightness and a rubber film 25b, which is a flexible film that is easily deformed, so that the inside of the air-liquid conversion device main body 25a is filled with a working liquid chamber 25c.
And an air chamber 25d. The working liquid chamber 25c also functions as a working liquid reservoir.

Then, the air tank 4 and the air-liquid conversion device 2
The switching valve 29 and the control valve 28 are connected to the first pipe 30 that connects to the air chamber 25d of No. 5. The switching valve 29 has a drain position a and a communication position b as shown in FIG. 2, and takes the communication position b by a signal generated by the ON operation of the retarder switch 31, so that the pressure air from the air tank 4 causes the control valve 28 to operate. After that, it is supplied to the air chamber 25d of the air-liquid conversion device 25, and the retarder switch 31
Since the drain position a is taken by the signal due to the OFF operation of (1), the pressure air from the air tank 4 is shut off and the pressure air in the air chamber 25d of the air-liquid conversion device 25 is drained to the outside.

The control valve 28 includes a sprung portion 32 of the vehicle.
And has a function of controlling so that the pressure on the air chamber 25d side in the first pipe 30 increases as the sprung weight increases. In FIG. 5, when the rod 28a is pushed downward, the piston 28e is seated on the inlet exhaust valve body 28i.
The b side is closed, the inlet port 28c is opened, and the pressurized air from the first pipe 30a on the air tank 4 side is sent to the chamber 28d.

This pressure air flows out from the first pipe 30b on the air chamber 25d side of the air-liquid conversion device 25, and is also applied to the lower portion of the piston 28e through the equalizer orifice 28f, so that the elastic force of the return spring 28g is exerted. The spring 28h is assisted to compress the spring 28h, the piston 28e rises, and the inlet port 28c is closed to maintain the balance. In this way, the pressure on the downstream side is adjusted according to the pushing amount of the rod 28a. When the rod 28a is raised and returned, the seat of the inlet exhaust valve body 28i on the piston 28e is released and the exhaust port 28b is opened.
The pressure in the chamber 28d decreases.

Thus, the rod 28a is attached to the sprung portion 32.
By mounting the control valve body 28j on the unsprung portion 33, the rod 28a is not pushed in when the vehicle is empty, and accordingly, the first pipe 30a on the air tank 4 side to the first chamber on the air chamber 25d side of the air converter 25 is installed. No pressurized air is sent to the pipe 30b, and it becomes point a in FIG. 3 (control pressure =
0 kg / cm ² ), the rod 28a is pushed down due to the lowering of the sprung portion 32 at the time of maximum loading, reaching point b in FIG. 3 (control pressure = 1 kg / cm ² ), and the first position on the air tank 4 side. Pressure air from the pipe 30a is the first pipe 30 on the air chamber 25d side.
It is sent to the air chamber 25d through b and pushes up the rubber film 25b.

Thus, the working liquid chamber 25c of the air-liquid conversion device 25 is connected to the closed circuit 21, and the air chamber 25d is connected to the air tank 4 via the control valve 28 and the switching valve 29 described above. Since the compressed air having a predetermined pressure can be supplied to 25d, the braking torque can be adjusted by adjusting the pressure of the working liquid in the closed circuit 21 and by extension the hydraulic retarder 11. Specifically, a relatively small braking torque (about 50 Kgf · m) is obtained at point a (control pressure = 0 kg / cm ² ) in FIG. 3, and at point b (control pressure = 1 kg /
A relatively large braking torque (about 90 Kgf · m) can be obtained in cm ² .

Further, the pressure chamber 1 of the pneumatic cylinder device 17
7c is a first pipe 30 which is on the downstream side of the switching valve 29.
It is connected to a by the second pipe 34. Then, since the switching valve 29 takes the communication position b by the signal from the ON operation of the retarder switch 31, the pressure air from the air tank 4 is supplied to the pressure chamber 17c of the pneumatic cylinder device 17, and the retarder switch 31 is turned OFF. Since the switching valve 29 takes the drain position a by the signal from the operation, the pressure air from the air tank 4 is shut off and the pressure air in the pressure chamber 17c is drained to the outside.

That is, when the retarder switch 31 is turned on, the switching valve 29 is brought into the communication position b, and the pressure air from the air tank 4 is passed through the first pipe 30 and the second pipe 34 to the pressure chamber of the pneumatic cylinder device 17. 17c, the movable pressure plate 14 located at one end is pushed through the diaphragm 17a, the connecting member 17b, and the second bearing 13b, and the pressure plate 14 is rotated relative to the clutch plate 18 that rotates integrally with the rotary shaft 10. Since 14 is pressed, the clutch device 13 is connected.

As a result, the first bearing 13 is attached to the case 11c.
Since the cylindrical support member 19 rotatably supported via a rotates, the rotor 16 integrated with the support member 19 rotates integrally with the rotary shaft 10. Then, the rotor 16 and the stator 1
The kinetic energy of the liquid filled in between 5 and 5 is converted into thermal energy to generate braking torque. The return drive of the pneumatic cylinder device 17 is performed by the O switch of the retarder switch 31.
The switching valve 29 is switched to the drain position a by FF operation, and the diaphragm 17a is switched by a spring (not shown).
And the connection member 17b is returned.

Next, the operation of the above embodiment will be described. While the vehicle is running, set the retarder switch 31 to O
Switch to N position to turn off accelerator pedal (not shown)
By satisfying additional conditions such as conditions, the switching valve 29 switches from the drain position a to the communication position b. Therefore, the compressed air from the air tank 4 is transferred to the pneumatic cylinder device 1.
7 is supplied to the pressure chamber 17c via the switching valve 29, and the clutch device 13 is connected.

As a result, the first bearing 13 is attached to the case 11c.
Since the support member 19 that is rotatably supported via a or the like rotates, the rotor 16 that is integral with the support member 19 does not rotate.
And start to rotate together.

On the other hand, when the switching valve 29 takes the communication position b, the pressure air from the air tank 4 also reaches the control valve 28 through the first pipe 30. The control valve 28 is interposed between the unsprung portion 32 and the unsprung portion 33 of the vehicle, and the pressure in the first pipe 30b on the air chamber 25d side increases as the sprung weight increases, that is, the load increases. Has a function of controlling so as to increase. As a result, when the vehicle is empty, the pressure of the working liquid in the working liquid chamber 25c, the closed circuit 21 and the hydraulic retarder 11 is adjusted by the control pressure (0 Kg / cm ² ) corresponding to the point a shown in FIG. A small braking torque is generated.

When the load is relatively large,
A relatively high control pressure (0 to 0) between points a and b shown in FIG.
The pressure of the working liquid in the working liquid chamber 25c, the closed circuit 21 and the fluid retarder 11 is adjusted to a high value in accordance with 1 kg / cm ² ) and a relatively large braking torque is generated. in this way,
The braking torque generated by the fluid retarder 11 is continuously changed and generated according to the loaded load.

The braking torque by the fluid type retarder 11 is
Due to the self-pumping action of the rotor 16, in a circulating state in which the working liquid also serving as cooling flows in from the working liquid inlet 11a and flows out from the working liquid outlet 11b, the operation in which the kinetic energy is applied by the stirring of the rotor 16 The liquid collides with the stator 15 and is obtained while being transferred as heat to the working liquid. At the same time, the clutch device 13 is activated by the working liquid.
Can also be cooled.

FIG. 4 shows the relationship between the braking force of the front wheels and the braking force of the rear wheels, and the curve M shows the ideal braking force distribution during loading.
The curve N shows the ideal braking force distribution when the vehicle is empty, and the straight line Q
Shows the actual braking force distribution in a vehicle not equipped with the fluid retarder 11.

When the control valve 28 is set so that the control pressure (0 Kgf / cm ² ) shown at point a in FIG. 3 is output when the vehicle is empty, the rear wheel at point A ′ shown in FIG. 4 is based on this setting. The braking force is obtained by the hydraulic retarder 11. This A '
The point is that the friction coefficient of the wheel skid limit when empty is μ = 0.2.
Therefore, the occurrence of wheel lock due to the generation of the braking force of the rear wheel at the point A ′ is well avoided. On the other hand, at the maximum load, the control pressure (1K
If the control valve 28 is set so that gf / cm ² ) is output, the braking force of the rear wheel at point A shown in FIG. 4 can be obtained by the hydraulic retarder 11 based on this. As described above, at point A, the wheel skid limit when loaded is the friction coefficient μ =
Since the road surface is 0.2 or less, the occurrence of wheel lock due to the braking force of the rear wheel at point A can be well avoided.

Therefore, it is possible to generate a substantially constant vehicle deceleration without locking the wheels regardless of the loading conditions. Further, as shown in FIG. 4, the actual braking force distribution obtained by stepping on the brake pedal (not shown) while the fluid retarder 11 is operating as described above is 0-A'-B 'when the vehicle is empty, and Maximum loading 0-A-
It can be set to B, and both are close to the ideal braking force distributions N and M.

Of course, when the retarder switch 31 is turned off, the switching valve 29 returns to the drain position a, so that the clutch device 13 is disengaged, the rotation of the rotor 16 is stopped, and the pressurized air from the air tank 4 is released. At the same time as being shut off, the compressed air in the air chamber 25d of the air-liquid conversion device 25 is drained to the outside, and the braking torque by the fluid retarder 11 disappears.

In the above embodiment, the control valve 28 is constituted by the brake valve, but the control valve 28 can be constituted by the load sensing proportioning valve, and in that case. Is set so that the hydraulic pressure control start point (break point) of the load sensing proportioning valve is sufficiently generated by the pressure of the compressed air in the air tank 4.

[0038]

As can be understood from the above description,
According to the fluid type retarder apparatus of the present invention, the vehicle type deceleration by the fluid type retarder is controlled by the simple structure in which the fluid type retarder apparatus and the pressure air source are connected via the switching valve and the control valve. Since it is possible to obtain a substantially constant value regardless of the vehicle deceleration, it is possible to provide a proper vehicle deceleration without causing wheel lock, and to improve both the operation feeling and safety of the vehicle.

[Brief description of drawings]

FIG. 1 is a schematic view showing a fluid type retarder device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a fluid type retarder device.

FIG. 3 is a diagram similarly showing a braking torque-control pressure characteristic.

FIG. 4 is a diagram similarly showing a braking force characteristic of a front wheel-a braking force characteristic of a rear wheel.

FIG. 5 is a sectional view showing a control valve of the same.

FIG. 6 is a diagram showing a conventional example.

[Explanation of symbols]

4: air tank (pressure air source), 10: rotary shaft, 1
1: fluid type retarder, 11a: working liquid inlet, 11b:
Working liquid outlet, 11c: case, 12: retarder chamber, 1
3: Clutch device, 14: Pressure plate, 15:
Stator, 16: Rotor, 17: Pneumatic cylinder device (driving device), 17c: Pressure chamber, 18: Clutch plate, 21: Closed circuit, 23: Cooler for working liquid, 25: Air-liquid conversion device, 25a: Air-liquid conversion Device main body, 25b: rubber film, 25c: working liquid chamber, 25d: air chamber, 28: control valve, 29: switching valve, 30: first pipe (pipe), 31: retarder switch, 32: sprung portion, 3
3: unsprung part, 34: second pipe, a: drain position,
b: Communication position.

Claims (1)

[Claims] 1. A rotary shaft that rotates together with a wheel,
A fluid retarder having a rotor and a non-rotating stator, which is always filled with a working liquid, a clutch device driven by a drive device to connect or disconnect the rotor and the rotating shaft, and the fluid retarder. A closed circuit connecting between the working liquid inlet and the working liquid outlet of, a liquid-liquid conversion device for applying an air pressure to the working liquid in the closed circuit, and a fluid type retarder device comprising a pressure air source, The pipe connecting the pressure air source and the air chamber of the air-liquid conversion device takes a communication position by turning on the retarder switch, and takes a drain position by turning off the retarder switch to take air from the air-liquid conversion device. A switching valve that drains the interior of the vehicle and a valve installed between the sprung portion and the unsprung portion of the vehicle, and are controlled so that the pressure on the air chamber side in the pipe increases as the sprung weight increases. Hydraulic retarder and wherein the interposing in series and a control valve that.