JPH01101258A - Device for limiting drive slip - Google Patents

Abstract

PURPOSE: To provide space-saving constitution by forming a driver as an electromagnetic driver. CONSTITUTION: A control device 12 recognizes the presence of a driving slip and the magnitude of its rise, from the time intervals of signals from wheel speed sensors 8, 9 for driveable wheels and wheel speed sensors 25, 26 for wheels which are not driven. For example, when a driving slip exceeding an inconvenient slip value occurs at a driving wheel fitted with a wheel brake 6, the control device 12 controls a valve 10 to a locking position and excites an electromagnetic driver 5 by the method of pushing its pressure rod 21 toward the piston 14 of a brake pressure generator 3. Therefore the piston 14, within a cylinder 13, forms a pressure working on the wheel brake 6 through a connecting opening 18. As the driving slip decreases, the drive 5 is returned to a basic position and the valve 10 is opened. The wheel brake 7 is driven in the same way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for limiting drive slip, comprising one brake pressure generator for at least one left-hand drive wheel and one brake pressure generator for at least one right-hand drive wheel of an axle. a cylinder in each case, in which both brake pressure generators are arranged coaxially and mirror-symmetrically spaced from each other, and which are furthermore connected to at least one wheel brake. a movable piston, and a common drive arranged between the cylinders, the drive being capable of driving one of the two pistons at a time in relation to the slip limit. It is of the type that is switchable in two directions of action for the purpose of movement.

From the prior art periodical Fluid J (January 1984, pages 10 and 11), a drive slip limiting device is known in the wheels of the axle, which are driven via a differential. It has two brake pressure generators that act on hydraulic wheel brakes arranged on the wheels, the brake pressure generators having a cylinder,
It has a piston, a piston return spring, and an electromagnet for moving each piston against the piston return spring. The configuration in which two electromagnets are connected in this way is inconvenient. That is, when both electromagnets are connected at the same time, there is a drawback that a significantly high load is placed on the vehicle's in-vehicle power supply system.

In a second device disclosed in the periodical Fluid J, the brake pressure generators are coaxially spaced from each other and the piston return springs move the two stones in opposite directions. It is consistent with

In order to move the piston against the piston return spring, only one diaphragm drive is installed between the pistons, which is of course controllable in two working directions and is equipped with a diaphragm drive. , in a police box style,
One or the other piston is moved to generate brake pressure. The diaphragm drive is, for example, driven by underpressure from the intake conduit of the vehicle's prime mover. However, such a device has the disadvantage that during the time when the drive slip is being reduced, the prime mover of the vehicle provides power and therefore only a small negative pressure is created in the suction conduit of the prime mover. Therefore, it is necessary to provide a negative pressure accumulator with a large volume, which makes it difficult and expensive to integrate into the vehicle. Furthermore, even if a special vacuum pump is provided, it is still expensive and produces disturbing noise. Furthermore, the diaphragm drive must be constructed with a large volume, which disadvantageously reduces the working speed of the diaphragm drive.

OBJECT OF THE INVENTION The object of the invention is to improve a device of the type mentioned above.

Means for Solving the Problem The measure taken to solve the above-mentioned problem is to form the drive as an electromagnetic drive.

Effects of the Invention The advantage obtained by the invention is that it can be of a space-saving construction and can therefore be easily and inexpensively integrated into a vehicle.

The claims 2, 3 and 4 provide an arrangement for an electromagnetic drive in a device according to the invention.

In accordance with the claims, an advantageous electrically controlled configuration is obtained for the case in which the device according to the invention is intended for integration into a normal vehicle braking system. According to claim 6, an arrangement is obtained in which the valve is directly controlled by the electromagnetic drive of the device. According to claim 7, the valve is controlled by a piston producing brake pressure,
An arrangement is obtained with a guide bush for the valve body, which ensures precise guidance so that the valve body hits exactly against the valve seat and is therefore quickly sealed and closed. In addition, there is less wear due to accurate contact with the valve seat.
This also increases the service life of the valve.

Embodiment A first embodiment of the device 2 for limiting drive slip shown in FIG. Two wheel brakes 6,7 with possible wheel wells, wheel speed sensors 8,9 arranged on the wheels, two electromagnetically controllable valves 1
0.11 and a control device (CONTROL) 12.

Each brake pressure generator 3 , 4 comprises a cylinder 13 , a piston 14 having at least one piston seal member 15 slidable within the cylinder, and a piston return spring 1 .
It consists of 6. The cylinder 13 has an end wall 17 with a connecting opening 18 . The piston return spring 16 is connected to the end wall 1
7 and the piston 14 and is configured such that a piston return spring can overcome the friction of the piston seal member 15 along the cylinder 13 and press the piston 14 into the starting position. . In this case, the piston 14 has a further end wall 19 with an opening 20 arranged in the middle.
is held in a predetermined end position by.

Both cylinders 13 are aligned along a common axis such that both end walls 19 are back to back to each other. Furthermore, both end walls 19 are spaced apart from each other. An electromagnetic drive device 5 is installed between the end walls 19. This drive is shown schematically and each piston 1
It has two pressure lots 21, 22 towards 4.

The electromagnetic drive device 5 can be designed, for example, as a plunger-shaped magnet with an armature and two excitation coils arranged coaxially in a row, in which the plunger is rotated in an alternating manner. Although there is a difference, it can sink deeply by excitation of the excitation coil.

The device 2 is provided for cooperating with the wheel brakes 6.7, which are the normal operating brakes of the vehicle, so that there is a connection between the brake pressure source 24, which can be controlled, for example, by the pedal 23 and the connecting opening 18 of the cylinder 13. , electromagnetically controllable valve 1
0 or 11 is placed. As already indicated, the connection opening 18 is connected to the respective wheel brake 6 or 7.
is connected to. The valves 10, 11 are designed as two-point, two-position directional control valves and are open in their basic position. This allows the brake pressure coming from brake pressure source 24 due to operation of pedal 23 to be applied to valve 10. through it to the wheel brakes 6.7 and the brake pressure generator 3.
It reaches inside the cylinder 13 of 4. This allows normal braking of the vehicle.

The control device 12 includes a wheel rotation speed sensor 8 for a drivable wheel.
, 9 and, advantageously, wheel speed sensors 25, 26 of the non-driven wheels, not shown.
given the signal from. From the time interval of the signals applied to the control device 12, the control device knows whether a drive slip is present and to what extent this drive slip increases. Control device 12
However, if, for example, the wheel speed sensor 8 gives a wheel speed pulse with a rapid progression and it is recognized that this is the result of, for example, a starting rotation of the associated drive wheel, the control device 1
2 controls the valve 10 to the locking position, and the electromagnetic drive device 5
is excited in such a way that it pushes the pressure rod 21 of this drive towards the piston 14 of the brake pressure generator 3. The piston 14 thus creates a pressure in the cylinder 13 that acts on the wheel brake 6 through the connecting opening 18 .

In this case, the now closed valve 10 is connected to the brake pressure source 24
This prevents pressure medium from leaking into the drive and thereby overriding the drive slip limit. The brake pressure in the wheel brake 6 is such that excess drive torques, which would lead to undesirably high drive slips, are absorbed by the braking moment. The rotational speed of the drive wheels is therefore reduced, so that on the one hand tire wear is reduced and the drive wheels can generate lateral forces. The control device 12
Once it is recognized that the drive slip is now reduced or limited to an advantageous amount via the wheel speed sensor,
The electromagnetic drive device 5 is returned to a predetermined basic position and controlled, and the valve 10 is opened. This allows the brake pressure source 24
and wheel brake 6 are reconnected, and wheel brake 6 can again be used for normal braking controlled by brake pedal 23.

If a drive slip exceeding an unfavorable slip value occurs on the drive wheel on which the wheel brake 7 is arranged, the valve 11 is closed by the control device 12 in the manner already described for the wheel brake 6 and the electromagnetic drive 5 is controlled in such a way that the second pressure rod 22 of this drive moves the piston 14 of the second brake pressure generator 4. This creates a brake in the cylinder 13 that is transmitted through the connecting opening 18 to the wheel brake 7 and thus absorbs any excess drive torque. When the absorption of the excess torque leads to the desired reduction or limitation of the drive slip, the control device 12 returns the valve 11 to the predetermined open position and returns the electromagnetic drive 5 to the predetermined starting position.

As mentioned above, instead of configuring the electromagnetic drive 5 as a Gra/jar magnet whose mover is moved in two directions by means of two excitation coils, it is of course possible to construct the electromagnetic drive 5 as a magnet with a permanent magnetic polarization. A type drive can also be provided, so that one pressure rod 21 can be connected in the - plane to the first brake pressure generator 3 using, for example, only one coil which can be loaded in opposite current directions by the excitation current. and on the other hand, the other pressure rod 22 is activated for the second brake pressure generator 4. Of course, the electromagnetic drive 5 can also be designed in the form of a linear motor, in which case the cylinder 13 and the cylinder 14 can have a small diameter in accordance with the characteristics of the linear motor, thus limiting the drive slip. The pumping action of the piston 14 required for this is achieved by a relatively long travel distance. This reduces the weight of the linear motor.

In this case, it is immaterial whether the linear motor is a motor driven by direct current or is designed as a reluctance motor. Of course, each configuration is related to the type of in-vehicle power supply system of the vehicle.

The electromagnetically controllable valve 10.11 is connected to the brake pressure generator 3, 4.
It can be arranged separately or can be flanged to the end wall 17. Installation can be related to the type, for example whether or not commercially available valves are used.

A second embodiment of the device 2a of the invention shown in FIG. 2 differs from the device 2 of FIG. 1 in the following points.

This means that instead of electromagnetically actuated valves with their own electromagnets, valves 10a, 11a are used which can be controlled via the tabs 27 of the electromagnetic drive 5. For this purpose, for example, the pressure rod 21a of the electromagnetic drive 5,
22a is formed relatively long and is connected to an arm 28 which projects at right angles. Preloaded leaf springs 29 are fastened to these arms as electrical elements, and due to their preload, these leaf springs abut against the free end 30 of the arm 28. In this case, the leaf spring 29
are aligned between the two arms 28 and are pressed in the direction of the respective assigned pressure slot 21a or 22a by the prestressing of the plate. The barb 27 is oriented parallel to the pressure rod 21a or 22a and towards the free end 31 of the preloaded leaf spring 29.

The valves 10a and 11a have an opening spring 32 which acts in the direction of the barb 27 and thus in the direction of the free end 31 of the leaf spring 29.

If control device 12 detects an increase in drive slip, for example via wheel speed sensor 8, electromagnetic drive device 5 is switched on. ``This causes the electromagnetic drive 5 to move the pressure rod 21a towards the piston 14 of the first brake pressure generator 3, and at the same time the arm 28 fixed to the pressure rod 21a also moves the pressure rod in the direction of the valve 10a. move parallel to. By this,
The preloaded leaf spring 29 presses on the associated barb 27 and closes the valve 10a.

In short, using a mechanical connection between the electromagnetic drive 5 and the valve 10a, the same effect as the directly electromagnetically controlled valve 10 in the first embodiment of FIG. 1 is obtained. For this reason, further explanation of the functioning of the embodiment according to FIG. 2 is unnecessary. Of course, instead of the arm 28 and the leaf spring 29, another mechanical You can also think of other ways.

A third embodiment of the device 2b shown in FIG.
The embodiment differs from the illustrated embodiment in that the wheel brakes 6.7 can be separated from the brake pressure source 24 by means of valves 10b, llb integrated in the brake pressure generators 3, 4. For this purpose, a valve housing 33 is integrated into the end wall 17a of the cylinder 13a of the brake pressure generator 3, 4, on which the piston 14a and the sealing ring 15a can slide. The valve casings 33 are oriented in the same direction as the pistons 14a and each support one co-oriented id bush 34 in which each guide rod 35 is slidable. A closing spring 36 is provided between each guide bar 35 and the piston 14a assigned to the guide bar. At the end of the guide rod 35 opposite the closing spring there is in each case a spring receiver 37 and a valve closing body 38.
is fixed. In the same direction with respect to the guide rod 35,
A valve seat 39 is arranged on the valve closing body 38 and is arranged on the valve housing 33 . Starting from the valve seat 39 is a conduit 40 leading to the brake pressure source 24 . At a distance from each valve seat 39, the valve casing 33 is connected to the connecting opening 4.
1, and the brake conduit 4 is connected from this connection opening 41.
2 leads to each wheel brake 6 or 7.

In order to control the electromagnetic drive device 5, a control device (C
ONTROL) 12 is provided, and this control device is equipped with a wheel rotation speed sensor 8. 9. It is connected to 25°26. For example, if the control unit &12 recognizes via the wheel speed sensor 8 that the wheel brake 6 supplies brake pressure for reducing or limiting drive slip;
The electromagnetic drive 5 is controlled in such a way that the pressure rod 21 of the drive 5 moves the piston 14a. As a result, the guide bar 35 is moved via the closing spring 36 against the spring force of the opening spring 37a, which is integrated into the valve housing 33 and is pressed against the spring support 37. The valve closing body 38 thus approaches the valve seat 39 and closes this valve seat. As a result, when the piston 14a is further moved, the first
A brake pressure is created in the brake pressure generator 3 of the wheel, which brake pressure is transmitted along the guide bushing 34 into the connection opening 41 and then through the brake line 42 to the wheel brake 6 where excess drive torque is removed. Leads to absorption. Second
Since the brake pressure generator 4 has the same structure as the first brake pressure generator 3, the wheel rotation speed sensor 9 assigned to the wheel brake 7 sends the wheel rotation speed pulse to the control device 12. A description of drive slip reduction or drive slip limitation is omitted for the case in which the wheel brakes 7 are provided to act in a controlled manner.

All three embodiments have in common that the first brake pressure generator 3 or the second brake pressure generator 4 is actuated alternately by means of the electromagnetic drive 5. Therefore, only one wheel brake 6 or 7 can be controlled in each case. This ensures that if the electromagnetic drive 5 remains stuck in the operating position, only one wheel is braked in each case, and the other drive wheel is still able to drive the vehicle equipped in this way. In order to reliably guide the driver along the desired course, the reduction in the drive moment of the drive machine has the additional safety advantage that the wheels can grip the road without drive slip.

If the vehicle has drivable wheels on separate axles, the first
In particular, if the differential gear is located between the axis of the brake and the second axis, an additional brake pressure generator of the type described above is arranged.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a first embodiment of the device according to the invention;
FIG. 2 is a schematic diagram showing a second embodiment, and FIG. 3 is a schematic diagram showing a third embodiment. 2.2a.2b...device, 3...first brake pressure generator, 4...second brake pressure generator, 5...electromagnetic drive device, 6.7...wheel Brake, 8/9...
・Wheel rotation speed sensor, 10/10a/11b/11/1
1a/11b...Valve, 12...Control device, 13.1
3a...Cylinder, 14.14a...Piston, 1
5...Piston seal member, 15a...Seal ring, 16...Piston return spring, 17.17a...
End wall, 18... Connection opening, 19... End wall, 20...
・Opening, 21・21a・22・22a...pressure lot, 23...pedal, 24...brake pressure source, 25・
26...Wheel rotation speed sensor, 27...Socket, 28.
... Arm, 29... Leaf spring, 30, 31... Free end, 32... Opening spring, 33... Valve casing,
34... Guide bush, 35... Guide dedicated, 36.
...Closing spring, 37... Spring holder, 37a... Opening spring, 38... Valve closing body, 39... Valve seat, 40...
Conduit, 41... Connection opening, 42... Brake conduit 3
・4... Brake pressure generator 5... Electromagnetic drive device 3.4... Brake pressure generator

Claims (1)

[Claims] 1. A device for limiting drive slip, comprising one brake pressure generator for at least one left drive wheel and at least one right drive wheel of the axle,
These two brake pressure generators are arranged coaxially and spaced apart from each other in mirror-image symmetry, and furthermore each have a cylinder connected to at least one wheel brake and a piston movable in the cylinder. and has
Furthermore, it has a common drive arranged between the cylinders, which drive can be operated in two directions of action in order to displace in each case one of the two pistons in relation to the drive slip limit. Device for limiting the drive slip, characterized in that the drive is designed as an electromagnetic drive (5). 2. 2. Device according to claim 1, characterized in that the electromagnetic drive (5) has two excitation coils and an armature which is pulled alternately via the excitation coils. 3. 2. Device according to claim 1, characterized in that the electromagnetic drive (5) is designed as a permanently polarized drive, the direction of action of which is changeable by switching the magnetic flux direction of the coil current. . 4. 2. Device according to claim 1, characterized in that the electromagnetic drive (5) is designed as a linear motor. 5. The cylinder (13) is additionally connected to the wheel brakes (6, 7) of the drivable wheels with a brake pressure source (24) controlled by the driver; 5. The device as claimed in claim 1, further comprising an electromagnetically controllable valve (10, 11) which is closed when the device (5) is connected. 6. The cylinder (13a) is additionally connected to the wheel brakes (6, 7) of the drivable wheels with a brake pressure source (24) controlled by the driver, and to this connection a piston is additionally connected. (14) Electromagnetic drive device (
5. The device according to claim 1, further comprising a controllable valve (10a, 11a) which is closed via a flexible member (29) of 5). 7. A valve controlled by a piston via a spring and a barb has a valve seat and a valve closing body, the valve seat and valve closing body receiving a brake pressure source controlled by a driver from a cylinder. The valve (10
b. 5. The device according to claim 1, further comprising a guide bush (34) for (35).