JP2731921B2 - Temperature detection device for electromagnetic clutch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electromagnetic clutch which is mounted on a drive system from an engine in a vehicle or the like and which automatically performs a disconnection operation. The present invention relates to a temperature detecting device for detecting temperature.

[Conventional technology]

It has already been proposed by the present applicant that an electromagnetic clutch is used as a vehicle clutch, the clutch is automatically disconnected by controlling the clutch current, and the gear is loosened by a drag current. By the way, when the vehicle is running continuously under high load while generating a tire stack on a bad road such as a snowy road or a sandy ground, or when the tire locks during sudden braking,
The electromagnetic clutch slips and generates heat. If the heat generation is significantly increased, there is a risk of burning. Therefore, protection measures against such burning have been considered.

In order to prevent the electromagnetic clutch torque from being burnt, there is a prior art in Japanese Patent Application Laid-Open No. 58-163831, for example. Here, a clutch voltage is obtained from the voltage between both ends of the clutch coil, and a clutch current is obtained using a resistor connected in series to the coil. Further, it is disclosed that the coil temperature is directly calculated based on the coil resistance value, the coil temperature coefficient, and the like based on the clutch voltage and the clutch current, and the overheating is determined.

[Problems to be solved by the invention]

By the way, in the above prior art, since the voltage between the coil terminals is calculated only by subtracting the measured voltage value between both ends of the coil, an error occurs including the voltage drop in the coil circuit, and the voltage between the coil terminals is increased. However, there is a disadvantage that the accuracy and reliability of the coil temperature calculated by using the method are lacking. Here, in the electromagnetic clutch, since the coil is built in the rotating drive member or driven member, power is supplied by sliding contact between the slip ring and the brush. As for the voltage between the coil terminals, the voltage on the power supply side from the brush and the voltage on the ground side of the coil have to be measured. Therefore, the measured value of the voltage between the terminals of the coil includes the voltage drop of the brush portion and the like. . Therefore, the voltage between the coil terminals is calculated to be larger than the voltage between both ends of the coil alone, and the value of the coil temperature converted by the coil resistance and the coil temperature coefficient based on this is higher.

For this reason, it is essential to accurately determine the voltage between the coil terminals in consideration of the voltage drop in the coil circuit in order to improve the accuracy. In particular, the sliding contact portion between the brush and the slip ring has a variation and an error in assembling, and causes an increase in resistance due to aging. For this reason, it is not enough to add a constant to the correction of the voltage drop, and it is desired to always directly calculate the voltage drop. In addition, the voltage drop of the brush portion and the like can be used for clutch current control and the like, and it can be said that it is significant.

The present invention has been made in view of such a point, and an object of the present invention is to accurately calculate a voltage between coil terminals while always obtaining a voltage drop in a coil circuit, and to improve calculation accuracy of a coil temperature. It is an object of the present invention to provide an electromagnetic clutch temperature detecting device capable of detecting a temperature of an electromagnetic clutch.

[Means for solving the problem]

In order to achieve the above object, the temperature detection device of the present invention is
In an electromagnetic clutch temperature detecting device which detects a voltage between terminals of a clutch coil and a coil current and calculates a coil temperature based on these values, a coil circuit using the coil terminal voltage, the coil current and the coil temperature is used. A voltage drop calculator for calculating the voltage drop of the coil, a coil temperature calculator for calculating the coil temperature from the voltage between the coil terminals and the coil current and the voltage drop, and a voltage drop calculator and a coil temperature calculator Are calculated by inputting the latest coil temperature and voltage drop calculated by each other.

[Operation] Based on the above configuration, the voltage drop in the coil circuit is constantly calculated at the latest coil temperature. Then, based on the latest voltage drop, the voltage between the coil terminals is corrected to accurately calculate the coil resistance, and the coil resistance is converted by a coil temperature coefficient or the like to accurately calculate the latest coil temperature. In this way, both the voltage drop in the coil circuit and the coil temperature are calculated with high accuracy in a time series using the values of the other party.

〔Example〕

Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings.

First, referring to FIG. 1, a transmission system including an electromagnetic clutch to which the present invention is applied will be described. Reference numeral 1 denotes an electromagnetic clutch, 2 denotes an engine, and 3 denotes a transmission such as a manual transmission or an automatic transmission.

The electromagnetic clutch 1 includes a crankshaft 4 from the engine 2.
A drive member 7 is integrally coupled to the transmission 3 via a drive plate 5, whereas a driven member 9 having a clutch coil 6 is integrally spline-coupled to an input shaft 8 to the transmission 3 in a rotational direction. These drive members 7,
The driven member 9 is closely fitted through the gap 10, and the electromagnetic powder is accumulated in the gap 10 from the powder chamber 11. A slip ring 13 is provided on a shaft 12 coaxial with the input shaft 8 of the driven member 9.
The power supply brush 14 is in sliding contact with the slip ring 13.

Thus, the drive plate 5 and the drive member 7 rotate together with the crankshaft 4 during engine operation,
When power is supplied to the clutch coil 6 from the control system described later via the brush 14 and the slip ring 13, the magnetic powder that is connected between the drive member 7 and the driven member 9 in the form of a chain in the gap 10 between the drive member 7 and the driven member 9 at this time It accumulates to generate a binding force. The driven member 9 is integrally engaged with the drive member 7 by this coupling force, and the engine power of the crankshaft 4 is transmitted to the input shaft 8.

Next, the clutch control system will be described. The vehicle control system includes a vehicle speed sensor 15, an engine speed sensor 16 for detecting an ignition pulse and the like, an accelerator switch 17, for detecting depression of an accelerator, a shift position sensor 18, an air conditioner switch 19, and the like. The signals of these sensors and switches are input to the clutch control unit 21 of the control unit 20, and the clutch current is supplied or cut off to the clutch coil 6 via the drive unit 22 according to each energization mode. Control. Further, as a measure for preventing burnout of the electromagnetic clutch 1, voltage signals at a plurality of points in the circuit of the clutch coil 6 are input to the coil temperature detecting unit 28 and processed.
If the clutch coil 6 is overheated, an alarm 29 is issued, for example.

In FIG. 2, the coil temperature detection control system will be described.

First, the ground side of both ends of the clutch coil 6 and the brush 14
The voltages V ₁ and V ₂ on the power supply side are A / D-converted and input to the coil voltage detector 30, and the voltage V between the coil terminals is calculated by V = V ₁ −V ₂ . Further, a current detection resistor 27 is connected in series to the clutch coil 6, and the voltages V ₃ and V _{4 at} both ends of the current detection resistor 27 are also A.
/ D converted and input to the coil current detection unit 31, and the coil current I is calculated using the resistance value r of the current detection resistor 27 as I = (V ₃ −
V ₄ ) Calculated as / r.

The coil terminal voltage V and the coil current I are input to a coil temperature calculating unit 32 and a voltage drop calculating unit 33. The voltage drop calculating unit 33 outputs the coil terminal voltage V, the coil current I and the coil temperature calculating unit 32. The voltage drop D in the coil circuit is obtained by using the coil resistance R based on the coil temperature T of FIG. Further, the coil temperature calculation unit 32 obtains a coil resistance R using the coil terminal voltage V, the coil current I and the voltage drop D of the coil voltage drop calculation unit 33, and further obtains a coil temperature coefficient α and a predetermined temperature as a reference. Request coil temperature T with the coil resistance R _S at the time T _S. The coil temperature T is inputted to the overheat judging section 34 and is compared with, for example, the coil limit endurance temperature _TL . When T ≧ _TL , a warning signal is output to the alarm 29.

Here, the coil terminal voltage V and the coil current I are
For time series t ₀ , t ₁ ,... T _n-1 , t _n for each fixed time, V ₀ , V ₁ , V.
_{n-1, V n, I} 0, I 1, ... are read and calculated in I _n-1, I _n. If the time interval Δt in this case is small, it is assumed that the voltage drop D _n = D _n-1 when calculating the current coil temperature T _n , and
Can in the calculation of this voltage drop D _n regarded as the coil temperature T _n = T _n-1, the value T _n-1 of the voltage drop D _n and the coil temperature T _n are both previous partner, By calculating using D _n−1 , the degree of calculation is the highest.

Therefore, the voltage drop calculation unit 33 calculates the coil resistance R _n using the coil temperature T _n−1 , the coil temperature coefficient α, the coil resistance R _S , and the predetermined temperature T _S previously calculated in a certain cycle by the following equation. calculate.

_{R n = R S {1 +} α (T n-1 -T S) and the coil resistance R _n and voltage between the coil terminals V _n, a voltage drop D _n in the coil circuit with the coil current I _n, the following It is calculated by the formula.

_{D n = V n -I n ·} R n In addition, the coil temperature calculation unit 32, in the next routine of the voltage drop calculation routine, a voltage drop which is previously calculated
D _n-1, the voltage V _n across the coil terminals, the coil resistance R _n using a coil current I _n, is calculated by the following equation.

_{R n = (V n -D n} -1) / I n and the coil resistance R _n, the predetermined temperature T _S, the coil resistance R _S,
Using the coil temperature coefficient α, the coil temperature _Tn is calculated by the following equation.

T _n = {(R _n −R _s ) / α · R _S } + T _S This is a modification of the relational expression between the coil resistance R _n and the temperature.

It is to be noted that the calculation of the initial value D _o and the initial value T _o of the coil temperature of the voltage drop, may be given a first value D _o of the voltage drop as previously initial value.

Therefore, control of the electromagnetic clutch having such a configuration is described in the third section.
This will be described with reference to the flowchart in FIG.

First, the clutch current of the clutch coil 6 of the electromagnetic clutch 1 is controlled by the clutch control unit 21 in accordance with each energizing mode, and a clutch torque corresponding to the clutch current is generated to automatically make or break or control the torque. At this time, the voltage value V _1, based on V ₂ coil terminal voltage V _n of the ground side of the supply side and the clutch coil 6 of the brush 14, the voltage value V ₃ across the current sensing resistor 27, V ₄ and the resistance value coil current I _n based on the r is detected (step S1, S2).

Therefore, the process first proceeds from step S3 to step S4, where a voltage drop calculation routine is executed. Therefore, have received the latest coil resistance R _n using a previous coil temperature T _n-1, etc., calculates the voltage drop D _n based on the current brush characteristics in step S5. Thereafter, by clearing the flag 1 in step S6, the process proceeds from step S3 to step S7 next time to execute the coil temperature calculation routine. Therefore, seeking a resistance R _n of only the portion of the clutch coil 6 to correct the voltage V _n across coil terminals using the latest voltage drop D _n-1 and the like calculated in the previous rutin described above, in step S8 it is to calculate the temperature T _n of the portion of the clutch coil 6 through the resistor R _n, and the like.
The coil temperature T _n is compared with the limit value T _L at step S9,
If T _n <T _L , the flag 1 is set in step S10, and the above operation is repeated.

In this case, the slip of the electromagnetic clutch 1 is smaller lower temperature of the electromagnetic clutch 1, a small value of the resistor R _n.
On the other hand, a stack of tires, the slip of the clutch 1 is increased even if the temperature of the electromagnetic clutch 1 increases by a lock or the like, increases accordingly also coil temperature T _n and the resistance R _n. Thus, the heat generation of the clutch coil 6 is calculated according to the slip state of the electromagnetic clutch 1 without being affected by the outside air temperature. Therefore the coil temperature T _n is increased compared with the coil temperature T _n and the limit value T _L, the flow advances from T _n ≧ T For _L is determined that the superheated step S9 to step S11, to warn the driver in the alarm 29 . When Accordingly driver stops running, cut clutch current I _n is the clutch 1 is automatically cut, a clutch coil 6 When this condition is sustained is than cooled to decrease the temperature, thus burning of the clutch 1 Is prevented.

As mentioned above, although one Example of this invention was described, it is not limited to the said Example.

〔The invention's effect〕

As described above, according to the present invention, in the control system that calculates the coil temperature using the voltage, the current, and the temperature coefficient between the terminals of the coil in the electromagnetic clutch and prevents burnout based on the calculated temperature, Since the voltage between the coil terminals is corrected by always calculating the voltage drop, the voltage drop at the brush portion is removed, and the resistance and temperature of only the coil can be accurately detected.

Further, the voltage drop can always be accurately calculated from the coil resistance based on the latest coil temperature.

Further, the voltage drop and the coil temperature can be reliably calculated in each of the divided control routines.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram schematically showing an embodiment of a temperature detecting device for an electromagnetic clutch according to the present invention, FIG. 2 is a block diagram of a temperature detection control system, and FIG. 1 ... Electromagnetic clutch, 6 ... Clutch coil, 30 ...
Coil voltage detector, 31 ... Coil current detector, 32 ... Coil temperature calculator, 33 ... Voltage change detector

Claims (1)

(57) [Claims] 1. An electromagnetic clutch temperature detecting device for detecting a voltage between terminals of a clutch coil and a coil current and calculating a coil temperature based on these values, wherein the voltage between the coil terminals, the coil current and the coil temperature are detected. A voltage drop calculator for calculating a voltage drop in the coil circuit by using the coil voltage calculator; and a coil temperature calculator for calculating the coil temperature from the coil terminal voltage, the coil current and the voltage drop. And a coil temperature calculating unit for inputting and calculating the latest coil temperature and voltage drop calculated by each other, and calculating the temperature of the electromagnetic clutch.