JPH0516774A - Wheel speed detecting device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a wheel speed detecting device which does not require replacement of a sensor rotor or a controller even when a wheel diameter of a wheel or a gear ratio of a transmission mechanism changes. A wheel speed sensor including a rotor having a shape that rotates together with a rotating shaft connected to a wheel and that regularly changes in a circumferential shape, and a pickup sensor that detects the shape of the rotor and outputs a pulse signal. 9 are provided. A controller 8 for calculating the wheel speed based on the pulse signal is provided. The controller 8 is selectively switched according to at least one of the wheel diameter of the wheel and the gear ratio of the speed change mechanism provided between the wheel and the rotary shaft on which the rotor is disposed, and the correction signal is output. Correction signal output means 8 for outputting
Based on this correction signal, the wheel speed adapted to the wheel diameter or the gear ratio is calculated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle wheel speed detecting device, for example, a wheel speed detecting device suitable for an antiskid brake system of a vehicle for controlling a hydraulic pressure of a brake according to a wheel speed to prevent skid. ..

[0002]

2. Description of the Related Art Conventionally, for example, a wheel speed detecting device used in an anti-skid brake system of a vehicle for controlling a hydraulic pressure of a brake in accordance with a wheel speed to prevent skid has a rotation connected to a wheel, for example. The sensor rotor (rotor), which is arranged on the shaft and rotates together with the rotating shaft, is formed to face the tooth surface of the sensor rotor (rotor) formed in the shape of a gear. It is composed of a wheel speed sensor (sensor means) composed of an output pickup sensor and a controller (calculation means) for calculating the wheel speed based on the pulse signal output from the wheel speed sensor.

More specifically, the sensor rotor is coaxially disposed on, for example, an axle shaft (rotating shaft) of a wheel, a drive shaft (rotating shaft) of a final reduction gear (transmission mechanism), and rotates integrally. To do. On the other hand, the pickup sensors are arranged correspondingly to the bearing housing of the axle shaft, the differential carrier of the final reduction gear, or the like. Then, when the sensor rotor rotates, the air gap between the sensor rotor and the pickup sensor changes due to the tooth row (shape) provided on the outer peripheral surface (on the circumference) of the sensor rotor, and the air gap between the sensor rotor and the pickup sensor is provided. The magnetic flux of the permanent magnet changes, and an AC voltage, that is, a pulse signal is generated in the coil in the pickup sensor. Then, the controller calculates the angular velocity of the wheel from the frequency or cycle of this pulse signal, and multiplies this by the wheel diameter, more specifically, the dynamic load radius of the wheel to calculate the wheel speed.

Therefore, when using wheels having different wheel diameters and when using final reduction gears having different reduction ratios (gear ratios), the wheel diameters of the wheels to be mounted and the reduction gears of the final reduction gear are respectively reduced. A sensor rotor having a number of teeth adapted to the ratio and / or a controller adapted to them are prepared and attached.

[0005]

However, in the above-described conventional wheel speed detecting device, the number of kinds of wheel diameters of wheels and the number of kinds of reduction ratios of final reduction gears of a vehicle in which the wheel speed detecting device is mounted are set. Therefore, the corresponding sensor rotor or controller must be prepared in advance, resulting in a significant cost increase.

In particular, the former wheel diameter is often changed by the user after shipping, and it is extremely troublesome and expensive for the user to replace the sensor rotor or controller each time. Becomes The present invention has been made to solve such a problem, and the wheel diameter of the wheel, or the gear ratio of the speed change mechanism provided between the wheel and the rotating shaft on which the sensor rotor is disposed, It is an object of the present invention to provide a wheel speed detecting device that can reduce the cost drastically without changing the sensor rotor or controller even if it changes.

[0007]

In order to achieve the above-mentioned object, according to the present invention, it is arranged on a rotary shaft connected to a wheel of a vehicle and rotates together with the rotary shaft, and is regularly arranged on the circumference. To a pulse signal output from the sensor means, and a sensor means including a rotor having a shape that changes in a direction and a pickup sensor that is arranged so as to face the rotor and that detects the shape of the rotor and outputs a pulse signal. In a wheel speed detecting device including a calculating means for calculating a wheel speed based on the wheel diameter, the calculating means is provided between a wheel diameter of a wheel to be mounted and a rotation shaft on which the wheel and the rotor are arranged. With a gear ratio of the speed change mechanism that changes the number of revolutions, with a correction signal output unit that selectively outputs a correction signal that is selectively switched corresponding to at least one, based on the correction signal output by the correction signal output unit, Characterized by calculating the wheel speed adapted respectively to wheel diameter or the speed-change ratio.

[0008]

In the above wheel speed detecting device, the calculating means is
In the case where it is selectively switched according to the wheel diameter of the wheel to be mounted, and if a speed change mechanism for changing the number of revolutions is provided between the wheel and the rotating shaft on which the rotor is arranged,
There is provided a correction signal output means for selectively outputting a correction signal, which is selectively switched according to the diameter of the mounted wheel and the gear ratio of the speed change mechanism, and based on the correction signal, the wheel diameter or the gear ratio is changed. The wheel speed adapted to each ratio is calculated. Therefore, even if the diameter of the wheel to be mounted or the gear ratio of the speed change mechanism changes, the calculation means can always correctly calculate the wheel speed based on the pulse signal output by the sensor means by the action of the correction signal output means. You can

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a specific configuration of an anti-skid brake system for a vehicle in which the wheel speed detecting device of the present invention is implemented. First of all, the anti-skid brake system of the vehicle is the slip of the wheel due to the brake operation while the vehicle etc. is running on the low μ road surface such as the road surface wet with rain or snow road, and also on the high μ road surface. Even if there is, the wheel slip caused by the sudden braking operation, that is, the locking of the wheel, is suppressed by properly controlling the hydraulic pressure of the brake, thereby preventing skid of the vehicle etc. during braking operation and ensuring steering stability. In addition, it is a system that attempts to shorten the braking distance.

The unskid brake system shown in FIG. 1 is equipped with a tandem master cylinder 1 with a vacuum brake booster. This master cylinder 1
Are actuated by the brake petals 2. From the master cylinder 1, two master cylinder side brake lines 3,
4 extends to the brake lines 3 and 4 on the master cylinder side.
Are connected to the wheel brakes 6 of the respective wheels 12 via the brake pressure adjusting device 5 via corresponding branch brake lines 7. The brake pipeline 3 is connected to the wheel brakes 6 of the right front wheel (FR) and the left rear wheel (RL) via the brake pressure adjusting device 5 and the two brake pipelines 7, respectively, and the brake pipeline 4 is , Through the remaining two brake pipes 7 from the brake pressure adjusting device 5 to the left front wheel (F
L) and the right rear wheel (RR) are connected to the wheel brakes 6, respectively. That is, the brake pipe lines extending from the master cylinder 1 to the wheel brakes 6 are arranged in a so-called diagonal split system.

The brake pressure adjusting device 5 has a tendency that one wheel of a vehicle is locked during a brake operation, and when an anti-skid brake control (ABS) described later is started, the brake hydraulic pressure in the wheel brake 6 at the wheel is adjusted. Is released to release the lock tendency of the wheels, and thereafter, the brake hydraulic pressure is maintained or increased depending on the rotational movement of the wheels.

Since various structures are known for the brake pressure adjusting device 5 described above, the description of the brake pressure adjusting device 5 is omitted here, but the operation of the brake pressure adjusting device 5 is performed by the controller. It is controlled by (calculation means) 8. This controller 8 is for each wheel 1
Wheel speed sensors (sensor means) for detecting the wheel speeds of 2
It is electrically connected to a pickup sensor 9b of 9, a brake switch 10 for detecting depression of the brake pedal 2, and the like.

FIG. 2 shows the structure of the above-mentioned wheel speed sensor 9 provided on each wheel in the case of the drive wheel. Reference numeral 11 denotes an outboard joint shaft (rotating shaft), the inner end of which is connected to an axle shaft (not shown) to receive the driving force of the engine, and the outer end of which is spline-coupled with an axle hub 11d.
The engine driving force is transmitted to the wheel 12 screwed to d. Also, the outboard joint shaft 11 is 2
The bearing housing 11a is rotatably supported by the bearing housing 11a through the deep groove ball bearings 11b and 11c.
Is fixed to the suspension arm 11e.

Then, the deep groove ball bearings 11b, 11 described above are used.
The sensor rotor (rotor) 9a of the wheel speed sensor 9 is coaxially fitted and inserted in the outboard joint shaft 11 between c and rotates integrally with the outboard joint shaft 11. The sensor rotor 9a is formed in a disk shape, and a required number of teeth (shape) are regularly arranged in a gear shape on the outer peripheral surface (on the circumference).

On the other hand, the above-mentioned bearing housing 11
In a, the pickup sensor 9b of the wheel speed sensor 9 is
The sensing portion is attached so as to face the tooth surface of the sensor rotor 9a. The pickup sensor 9b contains a permanent magnet and a coil, and when the sensor rotor 9a rotates, the air gap between the sensor rotor 9a and the pickup sensor 9b changes due to the action of the teeth on the outer peripheral surface of the sensor rotor 9a. Along with this, the magnetic flux generated by the permanent magnet changes to generate an AC voltage in the coil. That is, the pickup sensor 9b generates a pulse signal having a frequency proportional to the rotation speed of the sensor rotor 9a.

The above-described constructions of the wheel speed sensor 9, that is, the sensor rotor 9a and the pickup sensor 9b are substantially the same for the non-driving wheels, and therefore the description thereof is omitted. Next, as shown in FIG. 3, the controller 8 described above is housed in a thin box-shaped control box 8a, and is arranged in the body trim inside the vehicle compartment. On one side of the control box 8a, for example, four switch positions W, X, Y, Z as shown in FIG.
The changeover switch 8b is arranged so that it can be changed over from the outside of the control box 8a.

The controller 8 is composed of a control circuit, a power supply monitoring circuit and the like. FIG. 5 shows a simplified block diagram of the control circuit of the controller 8.
That is, the control circuit of the controller 8 is generally an input amplifier circuit 8c and a frequency conversion circuit (correction signal output means) 8
d, an ABS control circuit 8e, and an amplifier circuit 8f. The wheel speed sensor 9 provided on each wheel 12 is connected to the ABS control circuit 8e via the input amplification circuit 8c and the frequency conversion circuit 8d, respectively. The output of the ABS control circuit 8e is connected to the input of the brake pressure adjusting device 5 via the amplifier circuit 8f, respectively. The brake switch 10 described above is connected to the ABS control circuit 8e.

The changeover switch 8b described above is connected to the frequency conversion circuit 8d. The four switch positions W, X, Y, and Z of the changeover switch 8b are, as shown in Table 1 below, wheels of four types of wheels 12 that can be mounted on a vehicle equipped with the present anti-skid control system. The diameter, more specifically, the diameter can be selectively and manually switched according to the dynamic load radii S1, S2, S3, S4 of the wheels 12.

[0019]

[Table 1] Then, by switching the changeover switch 8b,
The frequency conversion circuit 8d converts the frequency of the pulse signal output from each wheel speed sensor 12 into a frequency corresponding to the dynamic load radius of the mounted wheel and inputs it to the ABS control circuit 8e.

Next, the procedure of the ABS processing step by the controller 8 will be described with reference to FIGS. First,
The controller 8 inputs the pulse signal output from each wheel speed sensor 9 (step 10). The input pulse signal is input to the frequency conversion circuit 8d via the input amplification circuit 8c. Here, the controller 8 frequency-converts (corrects) the amplified pulse signal in the frequency conversion circuit 8d according to the switch position of the changeover switch 8b, that is, the dynamic load radius of the mounted wheel 12 (step 14). .. More specifically, when the dynamic load radius is comparatively large, the frequency of the pulse signal is increased in proportion to the expansion amount of the dynamic load radius, and when the dynamic load radius is comparatively small, the frequency of the pulse signal is increased. Is reduced in proportion to the reduction amount of the dynamic load radius. The wheel speed is obtained by multiplying the angular velocity of the wheel 12 by the dynamic load radius of the wheel 12, as described later. . In other words, even if the dynamic load radius of the mounted wheel 12 changes,
By switching the changeover switch 8b, the pulse signal corrected so as to be adapted to the dynamic load radius of the wheel 12 based on the pulse signal output from each wheel speed sensor 9 is
It can be input to the BS control circuit 8e.

Next, the ABS control circuit 8 of the controller 8
The e receives the corrected pulse signal from the frequency conversion circuit 8d described above, calculates the angular velocity of the wheel 12 based on the frequency of the corrected pulse signal, and outputs the calculated angular velocity to the wheel 12
The wheel speed VW of each wheel 12 is calculated by multiplying by the dynamic load radius of (step 15). The wheel speed VW thus obtained is temporarily stored in the memory.
Then, the wheel acceleration / deceleration GVW (VWn-VWn-1) of each wheel 12 is calculated based on the wheel speed VWn calculated this time and the wheel speed VWn-1 calculated last time (step S16). ).

In the next step S18, the reference vehicle speed VR
EF is calculated. When the reference vehicle speed VREF is obtained, the process proceeds to the next step S20, and the slip amount Δ of each wheel is
V is calculated. When the slip amount ΔV is calculated, the process proceeds to step S22, in which the slip amount ΔV and the wheel acceleration / deceleration GVW are referred to by referring to the brake pressure increase / decrease map stored in advance in the memory, that is, the basic pressure increase / decrease map. The control mode of the brake pressure is selected. That is,
In the pressure increasing mode, the brake pressure is increased by 0.5 kg / cm ² , for example, and in the pressure reducing mode, the brake pressure is decreased by a required value. Then, in the holding mode, the brake pressure is held at that value.

When the brake pressure control mode is set in step S22, the process advances to step S24, and the brake pressure adjusting device 5 described above based on the set control mode passes through the amplifier circuit 8f. Is activated.
Then, the brake pressure of the wheel brake 6 of each wheel 12 is actually reduced, held, or increased. Once the ABS operation is started, the above-described ABS processing step is repeatedly executed until the ABS operation end condition is satisfied.

In the above-mentioned embodiment, the sensor rotors 9a for the drive wheels are arranged on the outboard joint shafts 11 of the drive wheels, respectively. Instead of this, as shown in FIG. The pair of wheel speed sensors 27 can be arranged in the final reduction gear (transmission mechanism) 28. As a second embodiment, a case where the sensor means is arranged in the final reduction gear 28 will be described below. However, the description of the common parts with the first embodiment will be omitted.

In FIG. 8, reference numeral 20 indicates a drive shaft (rotating shaft) of the final reduction gear 28. The drive shaft 20 is rotatably supported by a differential carrier 23 via conical roller bearings 21 and 22. One end (not shown) of the drive shaft 20 is connected to the propeller shaft and receives the driving force of the engine. A drive pinion 20a is formed at the other end of the drive shaft 20, and the drive pinion 20a meshes with the ring gear 24 to transmit the rotational force, and deceleration is performed here.

A spacer (rotor) 25 is fitted on the drive shaft 20 between the conical roller bearings 21, 22. On the outer peripheral surface (on the circumference) of the spacer 25, a required number of teeth (shapes) are regularly formed in a gear shape.
On the other hand, in the above-mentioned differential carrier 23,
The pickup sensor 26 of the wheel speed sensor 27 is mounted in a liquid-tight manner with its sensitive portion facing the tooth surface of the spacer 25. The wheel speed sensor 27 composed of the spacer 25 and the pickup sensor 26 operates similarly to the wheel speed sensor 9 of the first embodiment. However, the wheel speed sensor 27 detects the average speed of both drive wheels driven via the final reduction gear 28.

Since the wheel speed sensor 27 is attached to the drive shaft 20 of the final reduction gear 28, the reduction ratio (gear ratio) of the final reduction gear is changed, or the same as in the first embodiment. When the wheel diameter of the wheel is changed, it becomes impossible to obtain the correct wheel speed. Therefore, in step 14 of the first embodiment, in correspondence with the wheel diameter of the wheels that can be attached to the vehicle to which the anti-skid brake system equipped with the present wheel speed detection device is attached and the reduction ratio of the final reduction gear. The frequency conversion is executed by the frequency conversion circuit (correction signal output means) 29d shown in FIG. That is, as shown in Table 2 below, this vehicle has four different wheel diameters T1, T2, T3, T4 and three different reduction ratios G1, G2, G3 different from the final reduction gears.
It can be fitted with wheels.

[0028]

[Table 2] Therefore, five kinds of switching modes A, B, C, D, E are set corresponding to the reduction ratios G1, G2, G3, G4 and the wheel diameters T1, T2, T3, T4.
Accordingly, the controller 29 of the second embodiment has five switch positions A, B, as shown in FIG.
A changeover switch 29b for C, D and E is provided.
The frequency conversion circuit 29d can be switched in five stages by switching the changeover switch 29b.

As described above, in the present wheel speed detecting device, even if the wheel diameter of the wheel or the reduction ratio of the final reduction gear is changed,
The correct wheel speed can always be detected and provided only by switching the changeover switch 8b or 29b provided in the controllers 8 and 29 from outside the controllers 8 and 29. The mounting position of the wheel speed sensor 9 on the wheel 12 is not limited to the outboard joint shaft 11 described above, and may be mounted on the axle hub 11d, for example.

The sensor rotors 9 and 25 are not necessarily limited to those formed in the shape of gears. For example, holes that pass through the sensor rotors 9 and 25 may be regularly arranged in a circle around the rotation axis. Then, as a method for obtaining the angular velocity of the wheel 12 from the pulse signal, for example, the period of the pulse signal may be detected instead of detecting the frequency of the pulse signal. At this time, the controllers 8 and 29 are
A cycle conversion circuit (correction signal output means) may be provided instead of the frequency conversion circuits 8d and 29d. Further, it is needless to say that the angular velocity of the wheel 12 may be obtained by correcting this using other characteristics of the pulse signal.

In the frequency conversion in step 14, the frequency conversion circuits 8d and 29d are not provided in the controllers 8 and 29, but the ABS control circuits 8e and 29e have the function, that is, the correction signal detecting means. You may let it be processed. The pickup sensors 9b and 26 are not necessarily limited to those using a permanent magnet and a coil. Various types, eg optical, can also be used.

The number of types of the wheel diameter of the wheel or the reduction ratio of the final reduction gear is not limited to the above-mentioned four or three types. It can be set appropriately.
The changeover switch 29b of the second embodiment is used for the wheel 12
And a switch for the final reduction gear 28,
Each may be individually arranged. Further, in the first and second embodiments, when the front and rear wheels 12 have different wheel diameters, the front wheel switch and the rear wheel switch may be separately arranged and individually arranged. And it is also possible to combine these suitably.

Further, the application of the present wheel speed detecting device is not limited to the above-mentioned anti-skid brake system, and it goes without saying that it can be applied to the detection of the wheel speed of various systems.

[0034]

As described in detail above, in the wheel speed detecting device of the present invention, the calculating means is provided between the wheel diameter of the wheel to be mounted and the wheel and the rotating shaft on which the rotor is arranged. With the gear ratio of the speed change mechanism provided to change the number of revolutions,
At least one of the correction signal output means is selectively switched to output a correction signal, and based on the correction signal output by the correction signal output means, the wheel diameter or the gear ratio is adapted to each wheel. Even if the diameter of the wheel to be mounted or the gear ratio of the speed change mechanism changes, the wheel speed is always calculated correctly based on the pulse signal output from the sensor means.

Therefore, as many rotors or calculating means as the sensor means can be installed in a vehicle equipped with the present wheel speed detecting device as many as the number of kinds of wheel diameters of wheels or the number of kinds of gear ratios of a speed change mechanism. Since it is not necessary to prepare in advance, it is possible to significantly reduce the cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing a specific configuration of an anti-skid brake system of a first embodiment of a wheel speed detecting device of the invention.

FIG. 2 is a partial sectional front view showing a specific configuration of a wheel speed sensor 9 in FIG.

3 is a perspective view showing a controller 8 in FIG. 1. FIG.

FIG. 4 is a front view showing a changeover switch 8b of the controller 8 in FIG.

5 is a block diagram showing a configuration of a control circuit of a controller 8 in FIG.

FIG. 6 is an AB executed by a controller 8 in FIG.
It is a flowchart which shows a part of S process step.

FIG. 7 is an AB executed by the controller 8 in FIG.
It is a flow chart which shows the remainder of the S processing step.

FIG. 8 is a partial cross-sectional front view showing the specific configuration of the second embodiment of the wheel speed detecting device of the present invention.

FIG. 9 is a front view showing a changeover switch 29d of a controller 29 of the second embodiment.

FIG. 10 is a block diagram showing a configuration of a control circuit of a controller 29 of the second embodiment.

[Explanation of symbols]

 5 Brake pressure adjusting device 6 Wheel brake 8 Controller (arithmetic means) 8b Changeover switch 8d Frequency conversion circuit (correction signal output means) 8e ABS control circuit 9 Wheel speed sensor (sensor means) 9a Sensor rotor (rotor) 9b Pickup sensor 11 Out Board joint shaft (rotating shaft) 11d Axle hub 12 Wheels 20 Drive shaft (rotating shaft) 25 Spacer (rotor) 26 Pickup sensor 27 Wheel speed sensor (sensor means) 28 Differential carrier 29 Controller (calculating means) 29b Changeover switch 29d Frequency conversion circuit (Correction signal output means) 29e ABS control circuit

Claims (1)

Claim: What is claimed is: 1. A rotor, which is arranged on a rotary shaft connected to a vehicle wheel, rotates together with the rotary shaft, and has a shape that changes regularly on a circumference, and a rotor facing the rotor. Wheel provided with a pickup means for detecting the shape of the rotor and outputting a pulse signal, and a calculating means for calculating a wheel speed based on the pulse signal output by the sensor means. In the speed detecting device, the calculating means includes a wheel diameter of a wheel to be mounted, and a gear ratio of a speed change mechanism that is provided between the wheel and a rotation shaft on which the rotor is disposed and that changes a rotation speed, A vehicle equipped with a correction signal output unit that selectively outputs a correction signal corresponding to at least one of them, and that is adapted to the wheel diameter or the gear ratio based on the correction signal output from the correction signal output unit. A wheel speed detection device characterized by calculating a wheel speed.