JP2003074599A - Magnetic flux density detector for electromagnetic clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate the deterioration of detection accuracy of magnetic flux density caused by the inclination of an electromagnetic clutch armature and also facilitate the wiring of harness in case of using a plurality of sensor coils for connecting therewith. SOLUTION: The electromagnetic clutch is constituted by that a core 21L fitted with an exciting coil 22L is confronted with an armature 23L so that the armature is attracted to the core 21 to transmit torque when the exciting coil 22L is conducted; sensor coils 35L are embedded respectively in a plurality of recessed parts 21a formed on the main surface 21c of the core 21L apart from one another in the peripheral direction, an annular harness 46L for connecting the plurality of sensor coils 35L with one another is attached to the end surface of a coil cover 45L, and an annular groove 23b is formed on the main surface 23a of the armature 23 to avoid the interference with the harness 46L.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic flux density detecting device for an electromagnetic clutch, which detects the magnetic flux density from a voltage induced in a sensor coil according to a magnetic flux density generated in a magnetic circuit including a core and an armature.

[0002]

2. Description of the Related Art A magnetic flux density detecting device for such an electromagnetic clutch has already been proposed by the present applicant in Japanese Patent Application No. 2001-238134. The above-mentioned conventional magnetic flux density detection device has a sensor coil housed in a recess formed in the annular main surface of the core, and a magnetic circuit including a core and an armature based on a voltage induced in the sensor coil by energizing the exciting coil. It is designed to detect the magnetic flux density generated in the.

[0003]

By the way, when the armature of the electromagnetic clutch is tilted and the air gap between the core and the armature becomes uneven in the circumferential direction, the magnitude of the magnetic flux of the magnetic circuit composed of the core and the armature is also in the circumferential direction. Becomes uneven. In such a case, since the sensor coil is provided only at one position in the circumferential direction of the annular core in the above-mentioned conventional one, the magnetic flux density at the position of the sensor coil changes depending on the inclination of the armature. However, there is a problem that the detection accuracy of the magnetic flux density decreases.

In order to solve this problem, it is considered that a plurality of sensor coils are arranged in the circumferential direction at a distance from each other and the magnetic flux density is detected by using the average value of the output of each sensor coil. However, when a plurality of sensor coils are used, a harness for connecting them to each other is required, and the handling of this harness must be considered. The simplest method is to support the harness on the main surface of the core opposite to the main surface of the amateur, but this causes the problem that the amateur interferes with the harness unless the air gap between the core and the amateur is extremely large. Occur. Also, if you store the harness in the space formed inside the core, interference with amateurs can be avoided, but if you do this,
There is a problem that the core structure becomes complicated and the number of parts and the processing cost increase.

The present invention has been made in view of the above circumstances, and compensates for a decrease in the detection accuracy of the magnetic flux density due to the inclination of the armature and, when using a plurality of sensor coils, a harness for connecting them. The purpose is to facilitate the handling of.

[0006]

In order to achieve the above-mentioned object, according to the invention described in claim 1, the annular main surface of the core around which the exciting coil is wound is provided with an annular armature through an air gap. A magnetic flux density detecting device for an electromagnetic clutch, wherein main surfaces are opposed to each other and electric power is supplied to an exciting coil to attract an armature to a core to transmit torque. Sensor coils for detecting the magnetic flux density are respectively arranged in the recesses, and an annular groove for accommodating a harness for connecting these sensor coils to each other is formed on the annular main surface of the armature of the electromagnetic clutch. A magnetic flux density detector is proposed.

According to the above structure, since the sensor coils for detecting the magnetic flux density are arranged in a plurality of circumferentially spaced recesses on the main surface of the core, the armature is inclined and the core and the armature are tilted. Even if the air gap between them becomes uneven in the circumferential direction, the magnetic flux density is detected by using the output of multiple sensor coils to eliminate the influence of the inclination of the amateur and improve the magnetic flux density detection accuracy. You can Moreover, since the harness that connects a plurality of sensor coils to each other is housed in the annular groove formed on the annular main surface of the amateur, without making the harness difficult to handle,
Moreover, it is possible to prevent the amateur from interfering with the harness without increasing the air gap.

According to the invention described in claim 2,
Magnetic flux density detection of the electromagnetic clutch that transmits the torque by attracting the armature to the core by energizing the excitation coil with the annular main surface of the core around which the excitation coil is wound facing the annular main surface through the air gap. A device,
Sensor coils for detecting magnetic flux density are respectively arranged in a plurality of circumferentially spaced recesses formed on the main surface of the core, and an annular groove for accommodating a harness for connecting these sensor coils to each other is formed in the core. A magnetic flux density detecting device for an electromagnetic clutch is proposed, which is characterized in that the magnetic flux density detecting device is formed on an annular main surface.

According to the above structure, since the sensor coils for detecting the magnetic flux density are arranged in the plurality of recesses formed in the main surface of the core so as to be spaced apart from each other in the circumferential direction, the armature is inclined and the core and the armature are inclined. Even if the air gap between them becomes uneven in the circumferential direction, the magnetic flux density is detected by using the output of multiple sensor coils to eliminate the influence of the inclination of the amateur and improve the magnetic flux density detection accuracy. You can Moreover, since the harness for connecting a plurality of sensor coils to each other is housed in the annular groove formed on the annular main surface of the core, the amateur can harness the harness without making it difficult to handle the harness and without increasing the air gap. You can avoid interfering with.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on the embodiments of the present invention shown in the accompanying drawings.

1 to 12 show a first embodiment of the present invention, FIG. 1 is a view showing the structure of a driving force distribution device, and FIG. 2 is a driving force at the time of turning to the right in a medium and low vehicle speed range. FIG. 3 is a diagram showing the action of the distribution device, FIG. 3 is a diagram showing the action of the driving force distribution device at the time of turning left in the middle and low vehicle speed range, and FIG. 4 is an enlarged view of the main parts of FIG.
5 is a sectional view taken along line 5-5 of FIG. 4, FIG. 6 is a sectional view taken along line 6-6 of FIG. 4, FIG. 7 is a sectional view taken along line 7-7 of FIG. 4, and FIG. 9 is a circuit diagram of the magnetic flux density detecting means, FIG. 10 is a graph showing the relationship between the output voltage of the sensor coil and the magnetic flux of the magnetic circuit, FIG. 11 is a block diagram of the control system, and FIG. 12 is the clutch engaging force and the magnetic flux density. It is a graph which shows the relationship of.

As shown in FIG. 1, a transmission M is connected to the right end of an engine E mounted horizontally on the front of the vehicle body of a front engine / front drive vehicle. The transmission M is connected to the rear of the engine E and the transmission M. A force distribution device T is arranged. Driving force distribution device T
The left front wheel WFL and the right front wheel WFR are connected to the left drive shaft AL and the right drive shaft AR, which extend from the left end and the right end of the left and right, respectively.

The driving force distribution device T includes a differential device D to which torque is transmitted from an external gear 3 that meshes with an input gear 2 provided on an input shaft 1 extending from a transmission M.
The differential device D comprises a double pinion type planetary gear mechanism, and a ring gear 4 formed integrally with the external gear 3.
And a planetary carrier 8 that supports a sun gear 5 coaxially arranged inside the ring gear 4, an outer planetary gear 6 that meshes with the ring gear 4, and an inner planetary gear 7 that meshes with the sun gear 5 in a state where they mesh with each other. Composed of. The differential device D is
While the ring gear 4 functions as an input element,
The sun gear 5 that functions as one output element is the left output shaft 9
The planetary carrier 8 that is connected to the left front wheel WFL via L and functions as the other output element is the right output shaft 9R.
Is connected to the right front wheel WFR via.

The carrier member 11 rotatably supported on the outer periphery of the left output shaft 9L is provided with four pinion shafts 12 arranged at 90 ° intervals in the circumferential direction, and the first pinion 13 and the second pinion shaft 13 are provided. The triple pinion member 16 in which the pinion 14 and the third pinion 15 are integrally formed is used for each pinion shaft 12
Each is rotatably supported by.

A first sun gear 17 which is rotatably supported on the outer periphery of the left output shaft 9L and meshes with the first pinion 13.
Is connected to the planetary carrier 8 of the differential device D.
Also, the second sun gear 18 fixed to the outer periphery of the left output shaft 9L
Engages with the second pinion 14. Furthermore, the left output shaft 9
A third sun gear 19 rotatably supported on the outer periphery of L meshes with the third pinion 15.

The number of teeth of the first pinion 13, the second pinion 14, the third pinion 15, the first sun gear 17, the second sun gear 18, and the third sun gear 19 in the embodiment are as follows.

Number of teeth of the first pinion 13 Zb = 17 Number of teeth of the second pinion 14 Zd = 17 Number of teeth of the third pinion 15 Zf = 34 Number of teeth of the first sun gear 17 Za = 32 Number of teeth of the second sun gear 18 Zc = 28 Number of teeth of third sun gear 19 Ze = 32 The third sun gear 19 can be coupled to the housing 20 via the left electromagnetic clutch CL, and the rotation speed of the carrier member 11 is increased by the engagement of the left electromagnetic clutch CL. To be done. The carrier member 11 can be coupled to the housing 20 via the right electromagnetic clutch CR, and the rotation speed of the carrier member 11 is reduced by the engagement of the right electromagnetic clutch CR. The right electromagnetic clutch CL and the left electromagnetic clutch CL
Is controlled by an electronic control unit U including a microcomputer.

The electronic control unit U has an engine torque T.
e, the engine speed Ne, the vehicle speed V, and the steering angle θ are calculated based on a predetermined program to control the left electromagnetic clutch CL and the right electromagnetic clutch CR.

When the vehicle turns right in the medium and low vehicle speed range, the right electromagnetic clutch CR is engaged by a command from the electronic control unit U as shown in FIG.
Is coupled to the housing 20 and stopped. At this time, the left output shaft 9L integrated with the left front wheel WFL and the right output shaft 9R integrated with the right front wheel WFR (that is, the planetary carrier 8 of the differential device D) are the second sun gear 18, the second pinion 14,
Since they are connected via the first pinion 13 and the first sun gear 17, the rotation speed NL of the left front wheel WFL is equal to the right front wheel W.
The speed is increased in accordance with the following equation with respect to the rotational speed NR of FR.

NL / NR = (Zd / Zc) × (Za / Zb) = 1.143 (1) As described above, the rotation speed NL of the left front wheel WFL is relative to the rotation speed NR of the right front wheel WFR. When the speed is increased, the right front wheel W, which is the turning inner wheel, is indicated by the hatched arrow in FIG.
A part of the torque of FR can be transmitted to the left front wheel WFL which is the outer turning wheel.

The carrier member 11 is connected to the right electromagnetic clutch C.
Instead of stopping by R, if the engaging force of the right electromagnetic clutch CR is appropriately adjusted to reduce the rotation speed of the carrier member 11, the rotation speed NL of the left front wheel WFL is changed to the rotation speed NR of the right front wheel WFR according to the reduction. In contrast, it is possible to increase the speed and to transmit an arbitrary torque from the right front wheel WFR which is the turning inner wheel to the left front wheel WFL which is the turning outer wheel.

On the other hand, when the vehicle makes a left turn in the medium or low vehicle speed range, the left electromagnetic clutch CL is engaged by a command from the electronic control unit U, and the third pinion 15 operates the third sun gear 19 as shown in FIG. It is coupled to the housing 20 via the. As a result, the rotation speed of the carrier member 11 is increased with respect to the rotation speed of the left output shaft 9L, and the rotation speed N of the right front wheel WFR is increased.
The speed of R is increased according to the following equation with respect to the rotation speed NL of the left front wheel WFL.

NR / NL = {1- (Ze / Zf) × (Zb / Za)} ÷ {1- (Ze / Zf) × (Zd / Zc)} = 1.167 (2) As described above When the rotational speed NR of the right front wheel WFR is increased with respect to the rotational speed NL of the left front wheel WFL, the left front wheel W, which is the turning inner wheel, is indicated by the hatched arrow in FIG.
A part of the torque of FL can be transmitted to the right front wheel WFR, which is the turning outer wheel. Also in this case, the left electromagnetic clutch C
If the rotational speed of the carrier member 11 is increased by appropriately adjusting the fastening force of L, the rotational speed N of the right front wheel WFR is increased in accordance with the increased speed.
R is increased with respect to the rotation speed NL of the left front wheel WFL, and the left front wheel WFL which is the turning inner wheel to the right front wheel WFR which is the turning outer wheel.
Any torque can be transmitted to. Therefore, when the vehicle runs at low speed, it is possible to improve the turning performance by transmitting a larger torque to the turning outer wheel than to the turning inner wheel. It is possible to reduce the torque transmitted to the outer turning wheel during high-speed traveling as compared to during the medium-low speed traveling, or conversely, transmit torque from the outer turning wheel to the inner turning wheel to improve the traveling stability performance.

As is apparent by comparing the expressions (1) and (2), the first pinion 13, the second pinion 14, the third pinion 15, the first sun gear 17, and the second sun gear 18 are shown.
By setting the number of teeth of the third sun gear 19 as described above, the speed increase rate from the right front wheel WFR to the left front wheel WFL (about 1.143) and the speed increase rate from the left front wheel WFL to the right front wheel WFR (about 1 .167) can be made substantially equal.

Next, the structures of the left and right electromagnetic clutches CL and CR will be described with reference to FIGS. The left and right electromagnetic clutches CL and CR are connected to the left and right output shafts 9L and 9R by the axis L.
The structure of the left electromagnetic clutch CL will be described as a representative of the structure because it has a structure that is substantially bilaterally symmetric with respect to the plane of symmetry P orthogonal to the. The reference numeral of the component of the right electromagnetic clutch CR is the subscript "L" of the reference numeral of the component of the left electromagnetic clutch CL.
Is changed to "R".

The left electromagnetic clutch CL housed inside the housing 20 formed of a non-magnetic material such as aluminum alloy is
A core 21L formed of a magnetic material and having a substantially cylindrical shape is provided.
The core 21L is fixed to the inner peripheral surface of the housing 20 such that it cannot rotate and cannot move in the axial direction (horizontal direction). An armature 23L, which is annularly formed of a magnetic material so as to face each other, is disposed so as to be movable left and right. A connector 36L for supplying power to the exciting coil 22L is provided in the housing 20. A sleeve 31 integral with the third sun gear 19 (see FIG. 1) is coaxially and relatively rotatably fitted on the outer periphery of the left output shaft 9L, and is transmitted to the inner peripheral surface of the armature 23L by a welding member W25. The cylindrical portion 25a is disposed between the outer peripheral surface of the sleeve 31 and the inner peripheral surface of the core 21L so as to be movable in the axial direction.

The transmission member 25 is provided on the inner peripheral surface of the housing 20.
Pressure plate 25b formed integrally with L and 5
The clutch plates 27L ... And the stopper plate 28L are spline-fitted S1 so that they cannot rotate but can move in the axial direction. The left side surface of the pressure plate 25b of the transmission member 25L opposes the right side surface of the rightmost clutch plate 27L so that it can come into contact therewith. Further, the five clutch discs 33L ... Are spline-fitted S2 so as to be non-rotatable and axially movable on the outer peripheral surface of the guide portion 32L integrally provided at the left end of the sleeve 31. These five clutch disks 33L ... Are alternately stacked on the five clutch plates 27L ... And one stopper plate 28L.

As is apparent from FIG. 5, the five clutch disks 33L ... Spline-fitted to the outer peripheral surface of the guide portion 32L integral with the sleeve 31 are attached to both side surfaces thereof so as to be aligned in the circumferential direction. Provided with a large number of facings 33a. On the other hand, as is clear from FIG. 6, the five clutch plates 27L ... Spline-fitted to the inner peripheral surface of the housing 20 are made of metal plates without facing, and the facings 33a of the clutch discs 33L. Can be directly contacted with.

The right electromagnetic clutch CR has a symmetrical structure with the left electromagnetic clutch CL with the plane of symmetry P interposed therebetween, but the guide portion 32L of the left electromagnetic clutch CL is integrally provided on the sleeve 31 which is integral with the third sun gear 19. On the other hand, the guide portion 32R of the right electromagnetic clutch CR is different only in that it is provided integrally with the carrier member 11.

As is apparent from FIGS. 7 and 8, the outer peripheral end face of the core 21L facing the armature 23L has 12 ends.
Three recesses 21a are formed at 0 ° intervals, and the sensor coil 35L is wound around the cylindrical sensor core 21b protruding in the axis L direction inside each recess 21a. The end surface of the sensor coil 35L is the main surface 21 of the core 21L.
The cap 21d, which is retracted one step from c, is fixed so as to cover the end surface of the sensor coil 35L.
It is arranged flush with 1c. A synthetic resin coil cover 45L is fixed so as to cover the exciting coil 22L, and the end surface of the coil cover 45L is also flush with the main surface 21c. The three sensor coils 35L ... Are an annular harness 46 fixed to the end surface of the coil cover 45L.
Connector 4 connected to L and further provided on housing 20
It is connected to 7L. An annular groove 23b is formed in the main surface 23a of the armature 23L that faces the main surface 21c of the core 21L. By storing the harness 46L in the annular groove 23b, the armature 23L is connected to the harness 46L.
It prevents from interfering with L.

That is, the main surface 23a of the amateur 23L is temporarily assumed.
Has no annular groove 23b, the amateur 23L
It is necessary to make the air gap G extremely large in order to avoid the interference between the armature 23L and the harness 46L. However, in this embodiment, the annular groove 23b is provided in the main surface 23a of the armature 23L, so that the armature 23L and the harness 46L are separated from each other. The air gap G can be made sufficiently small while avoiding interference. Also, the harness 46L is attached to the end surface of the coil cover 45L.
Therefore, the structure of the core 21L can be simplified and the number of parts and the processing cost can be reduced, as compared with the case where a space is formed inside the core 21L to store the harness 46L.

As shown in FIG. 9, the magnetic flux density detecting means 37L for detecting the magnetic flux density generated in the magnetic circuit composed of the core 21L and the armature 23L by exciting the exciting coil 22L is composed of a high frequency drive circuit 38L and an impedance detecting circuit. The circuit 39L and three sensor coils 35L ... The high frequency drive circuit 38L is the sensor coil 35.
L. is driven, and the impedance detection circuit 39L detects the impedance of the sensor coils 35L ... and outputs it to the electronic control unit U. When the magnetic flux density passing through the sensor coils 35L ... Is changed by the excitation of the exciting coils 22L, the impedance of the sensor coils 35L ...
The magnetic flux density can be known by detecting this impedance. Further, by using the total sum (or average value) of the outputs of the three sensor coils 35L ... Arranged at 120 ° intervals, the armature 23L is tilted so that the air gap G between the core 23L and the core 21L becomes uneven in the circumferential direction. Even if
The magnetic flux density can be accurately detected by eliminating the influence.

In this embodiment, the impedance is detected by using the eddy current. Eddy current is a current that circulates in a conductor when it is placed in a fluctuating magnetic field. If the sensor core 21b is made of a conductive material, an eddy current is generated in the sensor core 21b.
The impedance of the sensor coil 35L can be detected by utilizing this eddy current. That is, the high frequency drive circuit 3
When the sensor coil 35L is driven at a high frequency so that the magnetic flux in the sensor core 21b is not saturated at 8L, an eddy current is generated in the conductive sensor core 21b. Sensor core 21
In addition to impedance loss due to self-dielectric which is 90 ° out of phase with the drive wave,
Impedance loss occurs due to eddy currents that are 0 ° out of phase. The impedance loss due to the self-dielectric does not change if the frequency is constant because the magnetic flux in the sensor core 21b is not saturated. On the other hand, the impedance loss due to the eddy current fluctuates according to the magnetic flux density passing through the sensor coil 35L. Since the impedance obtained by combining the above two components shows a very large change with respect to the change in the magnetic flux density, the magnetic flux density can be known based on this impedance.

The reason why the impedance loss due to the eddy current changes according to the magnetic flux density is that the current amount of the eddy current actually changes depending on the magnetic permeability μ of the sensor core 21b. In general, in the case of a magnetic material, the magnetic permeability μ does not simply represent a constant but changes according to the magnetic flux density.

FIG. 10 shows an electromagnetic clutch CL of this embodiment.
It shows the result of actually measuring the relationship between the output voltage of the sensor coil 35L and the magnetic flux of the magnetic circuit for CR. From this graph, it can be seen that the output voltage and the magnetic flux density have a substantially proportional relationship in a predetermined range of the output voltage of the sensor coil 35L.

As described above, since the magnetic flux density generated in the magnetic circuit constituted by the core 21L and the armature 23L by the excitation of the exciting coil 22L changes according to the impedance of the sensor coil 35L, the magnetic flux is transmitted to the electronic control unit U. By storing the relationship between the density and the impedance in advance, the magnetic flux density can be detected based on the impedance detected by the impedance detection circuit 39L.

However, when power is supplied to the exciting coil 22L in order to engage the left electromagnetic clutch CL by a command from the electronic control unit U, as shown by a broken line in FIG.
A magnetic flux is formed along a closed magnetic path composed of 1 L and the amateur 23L, and the amateur 23L is excited by the exciting coil 22.
It is sucked toward L toward the left in the figure. Then, the transmission member 25L connected to the amateur 23L moves to the left,
The clutch plate 27L is provided between the pressure plate 25b provided on the transmission member 25L and the stopper plate 28L.
... and the clutch disc 33L are sandwiched. As a result, the clutch plate 27L that is spline-fitted S1 to the housing 20 and the clutch disc 33L that is spline-fitted S2 to the guide portion 32L are integrated, and the sleeve 31 that supports the guide portion 32L is attached to the housing 20.
Be combined with.

Similarly, the exciting coil 22R is engaged to engage the right electromagnetic clutch CR in response to a command from the electronic control unit U.
As shown by the broken line in FIG. 4, a magnetic flux is formed along the closed magnetic path composed of the magnetic material core 21R and the armature 23R, and the armature 23R is excited by the exciting coil 2
It is sucked to the right toward 2R. Then amateur 2
The transmission member 25R connected to the 3R moves to the right, and the clutch plate 27R is provided between the pressure plate 25b and the stopper plate 28R provided on the transmission member 25R.
And the clutch disks 33R ... Are sandwiched. As a result, the clutch plate 27R ... Spline-fitting S1 to the housing 20 and the clutch disc 33R ... Spline-fitting S2 to the guide portion 32R are integrated, and the carrier member 11 supporting the guide portion 32R is coupled to the housing 20. To be done.

As shown in FIG. 11, the electronic control unit U
Is a target fastening force calculation means M1 and a target magnetic flux density calculation means M
2, feedback control means M3, and drive circuit M4
And subtraction means M5.

The target engagement force calculating means M1 is an electromagnetic clutch CL for distributing a predetermined torque between the left and right front wheels WFL and WFR based on the engine torque Te, the engine speed Ne, the vehicle speed V and the throttle opening θ. , CR target fastening force Tt is calculated. Since there is a fixed relationship shown in FIG. 12 between the magnetic flux density generated by the excitation of the excitation coils 22L, 22R of the electromagnetic clutches CL, CR and the engagement force generated by the electromagnetic clutches CL, CR, the target magnetic flux is obtained. The density calculating means M2 retrieves the target magnetic flux density φt, which is the control amount generated by the exciting coils 22L and 22R from the target engagement force Tt of the electromagnetic clutches CL and CR, based on the map of FIG.

Excitation coil 22 of electromagnetic clutches CL and CR
The actual magnetic flux density φ generated by the excitation of L and 22R is detected by the magnetic flux density detecting means 37L and 37R, and the subtracting means M
The deviation φt−φ calculated by subtracting the actual magnetic flux density φ from the target magnetic flux density φt in 5 is input to the feedback control means M3. The feedback control means M3 uses the deviation φt-
Excitation coils 22L, 2 which are manipulated variables by PID calculation of φ
The target exciting current of 2R is calculated, and the drive circuit M6 excites the exciting coils 22L and 22R based on the target exciting current. As a result, one of the left and right electromagnetic clutches CL, CR is engaged with the target engagement force Tt, and the left and right front wheels WFL, WF
A predetermined torque is distributed among Rs.

Assuming that the target magnetic flux density φt is the excitation coil 2
If the target exciting current to be supplied to the 2L and 22R is calculated and the feedback control is performed based on the deviation between the actual exciting current detected by the current sensor and the target exciting current, the accuracy of the control deteriorates due to the following reasons. Will end up. That is, the core 21
Since the air gap G between the L, 21R and the armatures 23L, 23R changes depending on the degree of wear of the facings 33a, ... However, when the air gap G is large, the magnetic flux density decreases and the actual target engaging force T of the electromagnetic clutches CL and CR becomes less than the target engaging force Tt. Conversely, when the air gap G is small, the magnetic flux density increases and the electromagnetic force increases. This is because the actual target fastening force T of the clutches CL and CR becomes equal to or greater than the target fastening force Tt.

On the other hand, according to the present embodiment, the exciting coils 22L, 22L, based on the deviation between the actual magnetic flux density φ detected by the magnetic flux density detecting means 37L, 37R and the target magnetic flux density φt.
Since the exciting current supplied to the 22R is feedback-controlled, the electromagnetic clutch C can be used regardless of the size of the air gap G.
The actual fastening force T of L and CR can be precisely matched with the target fastening force Tt.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the first embodiment, the amateurs 23L and 23R are used.
Annular grooves 23b, 23b formed in the main surfaces 23a, 23a of the
The harnesses 46L and 46L are housed in the second embodiment, but in the second embodiment, the end faces of the coil covers 45L and 45R are connected to the core 21L,
The main surfaces 21c, 21c of 21R are retracted one step, and the harnesses 46L, 4 are formed in the annular grooves 21e, 21e formed therein.
6L is stored. The second embodiment can also achieve the same effects as the first embodiment described above.

Although the embodiments of the present invention have been described in detail above, the present invention can be modified in various ways without departing from the scope of the invention.

For example, in the first embodiment, the amateur 23
Annular grooves 23b, 23 on the major surfaces 23a, 23a of L, 23R
b, and in the second embodiment, the cores 21L, 2
Although the annular grooves 21e, 21e are formed in the main surfaces 21c, 21c of the 1R, the amateurs 23L, 23R and the core 2 are formed.
1L, 21R both major surfaces 21c, 21c; 23a, 2
You may form annular groove 23b, 23b; 21e, 21e in 3a.

[0048]

As described above, according to the invention described in claim 1, the sensor coil for detecting the magnetic flux density is provided in the plurality of recesses formed in the main surface of the core so as to be circumferentially separated from each other. Even if the amateurs are tilted and the air gap between the core and the amateurs becomes non-uniform in the circumferential direction, the magnetic flux density is detected using the output of multiple sensor coils, so the influence of the amateur tilts Can be eliminated to improve the accuracy of detecting the magnetic flux density. Moreover, since the harness that connects multiple sensor coils to each other is housed in the annular groove formed on the annular main surface of the amateur, the amateur can harness the harness without making it difficult to handle the harness and without increasing the air gap. You can avoid interfering with.

According to the invention described in claim 2,
Since the sensor coils for detecting the magnetic flux density are arranged in a plurality of recesses formed in the main surface of the core so as to be spaced apart from each other in the circumferential direction, the armature is tilted and the air gap between the core and the armature is set in the circumferential direction. Even if it becomes non-uniform, by detecting the magnetic flux density using the outputs of the plurality of sensor coils, it is possible to eliminate the influence of the inclination of the amateur and improve the magnetic flux density detection accuracy. Moreover, since the harness for connecting a plurality of sensor coils to each other is housed in the annular groove formed on the annular main surface of the core, the amateur can harness the harness without making it difficult to handle the harness and without increasing the air gap. You can avoid interfering with.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a driving force distribution device.

FIG. 2 is a diagram showing an operation of a driving force distribution device at the time of turning right in a medium and low vehicle speed range.

FIG. 3 is a diagram showing an operation of a driving force distribution device at the time of turning left in a medium and low vehicle speed range.

FIG. 4 is an enlarged view of a main part of FIG.

5 is a sectional view taken along line 5-5 of FIG.

6 is a sectional view taken along line 6-6 of FIG.

7 is a sectional view taken along line 7-7 of FIG.

FIG. 8 is an enlarged view of a main part of FIG.

FIG. 9 is a circuit diagram of magnetic flux density detection means.

FIG. 10 is a graph showing the relationship between the output voltage of the sensor coil and the magnetic flux of the magnetic circuit.

FIG. 11 is a block diagram of a control system.

FIG. 12 is a graph showing the relationship between clutch engagement force and magnetic flux density.

FIG. 13 is a diagram corresponding to FIG. 8 according to the second embodiment of the present invention.

[Explanation of symbols]

G air gap 21L core 21R core 21a recess 21c Main surface 21e annular groove 22L excitation coil 22R Excitation coil 23L amateur 23R amateur 23a main surface 23b annular groove 35L sensor coil 35R sensor coil 46L harness 46R harness

Continued front page    (72) Inventor Tatsuhiro Tomari             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory (72) Inventor Shinji Okuma             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory (72) Inventor Shinichi Inagawa             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory F term (reference) 3D039 AA02 AB01 AC07 AC39 AD03                 3J057 AA01 BB04 GA64 GB02 GB36                       GB37 HH01 JJ05

Claims (2)

[Claims] 1. An amateur (23L, 23) via an air gap (G) on an annular main surface (21c) of a core (21L, 21R) around which an exciting coil (22L, 22R) is wound.
The ring-shaped main surface (23a) of (R) is made to face each other, and by energizing the exciting coils (22L, 22R), the amateur (23
(L, 23R) is attracted to the cores (21L, 21R) to transmit torque, and is a magnetic flux density detection device for an electromagnetic clutch, which is circumferentially spaced from the main surface (21c) of the cores (21L, 21R). Sensor coils (35L, 35R) for detecting magnetic flux density are respectively arranged in the formed plurality of recesses (21a), and these sensor coils (35L, 35R) are arranged.
A magnetic flux density detecting device for an electromagnetic clutch, characterized in that an annular groove (23b) for accommodating harnesses (46L, 46R) interconnecting each other is formed on an annular main surface (23a) of an amateur (23L, 23R). 2. An armature (23L, 23) is provided on an annular main surface (21c) of a core (21L, 21R) around which an exciting coil (22L, 22R) is wound via an air gap (G).
The ring-shaped main surface (23a) of (R) is made to face each other, and by energizing the exciting coils (22L, 22R), the amateur (23
(L, 23R) is attracted to the cores (21L, 21R) to transmit torque, and is a magnetic flux density detection device for an electromagnetic clutch, which is circumferentially spaced from the main surface (21c) of the cores (21L, 21R). Sensor coils (35L, 35R) for detecting magnetic flux density are respectively arranged in the formed plurality of recesses (21a), and these sensor coils (35L, 35R) are arranged.
A magnetic flux density detecting device for an electromagnetic clutch, characterized in that an annular groove (21e) for accommodating harnesses (46L, 46R) for interconnecting is formed on an annular main surface (21c) of the core (21L, 21R).