JPH06196987A - Circuit device for car - Google Patents

Abstract

PURPOSE: To attain the prevention of overheat by providing one output path arranged with a 2nd switching means parallelly to the output block of 1st switching means and reducing the loss power of 2nd switching means rather than the loss power of 1st switching means. CONSTITUTION: An electric motor M is formed as a servo motor and based on a traveling velocity sensor 14, a signal V expressing traveling velocity is supplied to a 2nd means 13. Corresponding to characteristic curves stored in the 2nd means 13, a transistor T is driven by pulse modulation through a 1st means 2. The terminal voltage of electric motor M formed as a DC motor is changed by the traveling velocity sensor 14, 2nd means 13, 1st means 12 and transistor T. Thus, the transistor T is driven by a 2nd signal S so that the various revolutions of electric motor M are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor vehicle circuit, and more particularly to an automobile circuit having at least one first switching means and at least one output path extending in parallel with an output line of the first switching means. Circuit circuit device for automobile.

[0002]

Circuit devices for controlling voltage are known from the prior art in various ways. That is, for example, the voltage controller is Siemens & Halske AG
"Semiconductor switch sample (Halbleiter-Schaltbeisp
iele) April 1961, pages 80-89. This voltage controller has a switching transistor, whose conductor path with resistance is connected in parallel in its emitter-collector section. The parallel conductor path with this resistance is designed to absorb a portion of the current if the load current picked up from the voltage controller does not fall below a predetermined minimum value. This keeps the load on the transistor small.

DE-OS3933371 describes a power steering of a motor vehicle, in particular a power steering system for the parking speed range. In the above system, a speed reducer is arranged between the servo motor and a steering column or a drive device for mechanically adjusting the wheels. In that case, at least one clutch backing is arranged, and at least one interlocking member connected to the steering wheel side of the steering column is used when the torque is manually adjusted in the steering.
A drive connection is formed from the servo motor drive device to the steering transmission side of the steering column when the required clutch pressing force is generated by mechanically acting on one clutch back. In that case, the clutch-actuated gear is embodied as a hollow gear, which is mounted on a clutch boss which is fixedly connected in the drive steering column region. In particular, a servomotor (electric motor), which is driven and operates only in one direction of rotation, drives two gear wheels that rotate in opposite directions. In that case, the servomotor is controlled by the power transistor.

[0004]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a new and improved circuit arrangement in which the load on the switching transistor can be removed in an optimum manner under the given operating conditions. is there.

[0005]

This problem is solved by the features of claim 1. That is, according to the present invention, an automotive circuit circuit device having at least one first switching means and at least one output path extending in parallel to an output line of the first switching means, , At least one output path (1 extending in parallel to the output line of the first switching means (T)
1) is provided with a second switching means (R1), in which case the power loss of the second switching means (R1) is smaller than the power loss of the first switching means (T). A circuit device for an automobile is provided.

As described above, the automobile circuit device according to the present invention has at least first and second switching means having different power losses. At least one output path in which the second switching means is arranged is provided in parallel with the output section of the first switching means. In that case, the power loss of the second switching means is smaller than the power loss of the first switching means.

In a preferred embodiment of the circuit arrangement according to the invention, the second switching means with the lower power loss are operated according to the first signal, which first signal has the higher power loss. It is indirectly or directly related to the second signal applied to the input of the switching means.

The first switching means is, for example, a bipolar transistor or a field effect transistor (FE).
T, MOS-FET, etc.). When using a bipolar transistor, the second
Is arranged in parallel with the emitter-collector section (output section), and the second signal applied to the input of the first switching section is applied to the base of the bipolar transistor. . When using a FET or a MOS-FET, the output path provided with the second switching means is arranged in parallel with the source-drain section (output section) and is applied to the input of the first switching means. The second signal is FET or MOS
Applied to the gate of the FET.

Further, the second switching means having a small power loss is a semiconductor element (transistor, thyristor),
Or mechanical switch (relay) that can be driven electrically
It can also be formed as.

If, for example, the switching state of the transistor is changed by driving it with a pulse-width-modulated signal, the preferred embodiment of the circuit arrangement according to the invention is that the transistor is continuously conducting for a selectable period. When power is supplied, the second switching means is switched to the conductive position. Therefore, the second switching means is switched to the conductive position when the transistor driven by pulse width modulation is continuously driven for a predetermined time.

In another preferred embodiment, the switching means is capable of switching to the conducting position if the conductivity of the transistor exceeds a selectable conductivity threshold for a selectable period. This embodiment is particularly effective when the conductivity of the transistor changes continuously, that is, without pulse width modulation. In this embodiment it is particularly effective to place the resistor in series with the switching means (common mode controller at operating point).

The two embodiments described above ensure that the entire open or closed loop control circuit controlled by the transistor removes the load on the transistor without relatively large output fluctuations. In other words, the switching means arranged in parallel with the emitter-collector section of the transistor are such that their conductivity (possibly time averaged) is not significantly greater than the conductivity of the output paths arranged in parallel. It is only possible to switch to the conduction position. The unloading of the transistors according to the invention has the effect, for example, that the power losses of the conducting transistors can be reduced by means of output paths arranged in parallel. Such an effect is particularly effective when a large current flows through the conducting transistor and the transistor is accordingly heated to an unacceptably high temperature.

In a preferred embodiment of the circuit arrangement according to the invention, a transistor is used for the open / closed loop control of the speed of the electric motor, which electric motor acts, for example, as an actuator for electric power steering.
In the case of this type of power steering, the rotation speed of the servo motor is controlled according to the vehicle speed. Below a certain vehicle speed, for example 20 km / h, the transistor controlling the terminal voltage of the servomotor by pulse width modulation is continuously turned on. This is because a large servo torque is desirable in this speed range (parking range). In that case, the servomotor is loaded to the output limit. As a result, a power loss of about 40 W is generated in the transistor. This type of power steering control device is subject to a large ambient temperature (located in the engine room) at the same time, which makes it very difficult and expensive to implement. The temperature of the transistor may exceed the allowable limit temperature, especially if the parking process lasts for a long time, or if the parking process is performed continuously at short intervals.

The first step in lowering the temperature of the transistor is to connect the second power transistor in parallel with the power transistor. When the number of rotations of the servomotor is high, heat generation becomes extremely large in some cases, regardless of this method.

With regard to reducing the power dissipation of the circuit arrangement and for economical realization, it is preferable to use only one power transistor for driving the servomotor. This transistor, which conducts continuously below a certain speed (parking speed) (which requires maximum servo assistance during the parking process), is bypassed by connecting the relay contacts in parallel. When the speed threshold is exceeded (exited from the parking area) and the parallel connected relays are opened, the transistor will continue to turn the engine speed on from its conduction state by means of the corresponding pulse-width modulated signal. Shift to a state where it will be lowered. In this way, it is possible to avoid the occurrence of torque fluctuations or torque steps that the driver perceives with the steering wheel, even when moving from the parking speed range to a region where slight servo assistance by the electric motor is desirable. it can. That is, the driver completes the shift in a continuous and therefore imperceptible manner.

The circuit arrangement according to the invention makes it possible to reduce controller failures and thus to use such a controller at high ambient temperatures, for example in the engine compartment of a motor vehicle. . Furthermore, it is possible to reduce the amount of refrigerant for this type of control device. Furthermore, the use of the circuit arrangement of the present invention can reduce electromagnetic interference (EMV) of the overall system.

When using an electric steering system,
By means of the circuit arrangement according to the invention, the control device is mounted directly on the mechanical part of the steering system, for example on the steering gear,
Or the possibility of incorporating it opens. Moreover, the cooling amount is reduced, the number of power transistors connected in parallel is reduced, and the EMV is reduced.
The cost can be reduced by reducing (electromagnetic interference).

[0018]

Embodiments will be described below with reference to the accompanying drawings. In FIG. 1, reference numeral T is a transistor, R1 is a first relay, M is an electric motor, and R2 is a second relay.
Is a relay. The first means and the second means are indicated by reference numerals 12 and 13, respectively. Further, the reference numeral 14 indicates a traveling speed sensor. Furthermore, the reference characters KL30, KL15, and KL31 indicate voltage terminals.

In this embodiment, the electric motor M is formed as a servomotor. A signal V representing the traveling speed is supplied to the second means 13 on the basis of the traveling speed sensor 14. Due to the characteristic curve stored in the second means 13, the transistor T is pulse-width modulated and driven via the first means 12. Traveling speed sensor means 14,
By means of the second means 13, the first means 12 and the transistor T, it is possible to change the terminal voltage of the electric motor M, which in this embodiment is embodied as a DC motor. Various speeds of the electric motor M are thereby realized by driving the transistor T with the second signal S2.

The steering system is premised on an electric power steering having a transmission between a servomotor and a steering column or a drive for adjusting the wheels. In that case, at least one clutch backing is provided which, when the torque is adjusted manually on the steering wheel,
An interlocking member connected to the steering wheel side of the steering column mechanically acts on at least one clutch backing to generate a necessary clutch pressing force. Form a drive connection to. A power steering system of that kind is understood from the prior art mentioned above.

If an electric motor of this kind is designed as a DC motor, the speed of rotation of the electric motor can be varied by controlling the terminal voltage of the electromagnet of the electric motor. The average value of the terminal voltage is controlled by pulse width modulation by changing the on time of the power transistor. Especially when the on-time is relatively long, that is, when the terminal voltage is high, this transistor causes significant heat loss. To reduce the temperature of the power transistor, a second power transistor can be connected in parallel to the emitter-collector section of this transistor. If the two transistors are driven in the same way, the temperature of the two transistors will be lower than the temperature of one transistor when the on-time is long.

Particularly preferably, the emitter of the transistor
A relay is used in the output path provided in parallel with the collector section. If the desired speed of the electric motor is high and the transistor driven by the pulse-modulated signal is in continuous conduction, the relay is driven such that the output path extending in parallel to the transistor bypasses the transistor. To be done. Thereby, the winding loss of the relay can be reduced. When reducing the rotational speed of the electric motor, the relays in the parallel output paths are reopened, whereby the pulse width modulation drive of the power transistor can reduce the terminal voltage of the DC motor.

In FIG. 1, a first relay R1 connected in parallel with a transistor T for controlling the rotation speed of the servomotor M is used. First relay R1
Are driven by the first signal S1. This first signal S1 is generated in this embodiment in connection with the case where the running speed falls below or above a selectable threshold value, or above or below the threshold value. The judgment regarding this threshold value is made in the second means 13.

The circuit device is connected to the positive pole of the vehicle battery via the terminal KL30, and the circuit device is connected to the ground or the negative pole of the battery via the terminal KL31.
The second relay R2 connects the entire system via the terminal KL15 when the ignition or ignition switch of the internal combustion engine of the vehicle is turned on. If the ignition is turned off,
The system is disconnected via the terminal KL15 or the second relay R2.

Next, the functioning method of the circuit device of the present invention will be described with reference to FIG. In FIG. 2, the servo assistance U obtained by the servomotor M is described with respect to the traveling speed V. After falling below the speed threshold V1, maximum steering assistance is desired. The traveling speed threshold value V1 is, for example, a traveling speed threshold value above the traveling speed region in which vehicle replacement or parking operation is performed. When such an operation is performed, maximum steering assistance of the power steering system is desirable. This is achieved by selecting the pulse width of the second signal S2 such that the transistor T is in its continuous conducting state. If the traveling speed is below the speed threshold V1, the first relay R1 is connected by the first signal S1. Thereby, the transistor T is bypassed and only a slight winding loss due to the first relay R1 occurs. When the traveling speed threshold value V1 is exceeded, that is, when the vehicle is out of the speed range where parking or vehicle switching operation is generally performed, it is desirable to reduce the servo support. This reduction in servo assistance can be achieved by removing the servomotor M from coupling with the steering column when the number of revolutions is the same, or by gradually reducing the number of revolutions of the servomotor. By gradually reducing the rotational speed of the electric motor M, it is possible to make a particularly soft transition from the parking area to the normal travel area. At speeds above the threshold V1, the servo assistance can be selected such that the servo assistance decreases as the traveling speed increases, by optionally reducing the rotational speed. Reducing the servo assistance by the servomotor is obtained by switching off the first relay R1 by the first signal S1 in the region of the travel speed threshold V1. Thereby, the entire motor current flows through the transistor T for a short time. By reducing the pulse width of the second signal S2, the average value of the terminal voltage of the electric motor M can be reduced, which leads to a reduction in the rotational speed of the electric motor. Second means 1
Various characteristics of the steering assistance relating to the traveling speed can be realized by the characteristic curve stored in FIG. 3 (FIG. 2).

When the traveling speed exceeds the other traveling speed threshold value V2, the electric motor M is driven at the minimum number of revolutions or is completely shut off. In this region of high speed, it is desirable to have very little or no steering force assistance to ensure optimum road contact of the driver.

While the first relay R1 is connected (after the transistor T is conductively connected for a predetermined period), the transistor T can be made conductive. Alternatively, however, it is also possible to prevent the transistor T from conducting when the relay R is connected, so that the entire current flows through the first relay R1.

In order to further reduce unnecessary switching processes, it is possible to have the relay R on or off at a running speed threshold V1 in a hysteresis manner.

By using the circuit device of the present invention,
It is possible to reduce the amount of refrigerant due to the small heat generation. In addition, system electromagnetic interference (EMV)
Can be reduced, so that the circuit required for improving the EMV can be simplified, and accordingly, the cost can be reduced.

The bypassed transistor T can be formed, for example, as a field effect transistor (FET) or a bipolar transistor. In the case of a bipolar transistor, the output path is arranged to extend parallel to the emitter-collector section, and when using a FET the output path is arranged to extend parallel to the source-drain section. Therefore, the output path having the switching means with low power loss is configured to extend in parallel with the output section of the bipolar or field effect transistor.

In particular, in the circuit device of the present invention, a power transistor having a relatively large passage resistance (RDSON) can be used. This type of power transistor generally has the advantage of being cheap to obtain.

[0032]

As described above, according to the present invention, there is provided an automobile circuit device capable of removing the load of the switching transistor by an optimum method under a predetermined operating condition. As a result, it is possible to prevent overheating of the switching transistor and reduce the amount of refrigerant for the circuit. Furthermore, since the electromagnetic interference (EMV) of the system can be reduced, the circuit required to improve the EMV can be simplified, and the cost can be reduced accordingly. Also, it is possible to use a power transistor which is inexpensive but has a relatively large resistance.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of a circuit device of the present invention.

FIG. 2 is a diagram illustrating a functional method of the circuit device of the present invention.

[Explanation of symbols]

 T transistor R1 1st relay R2 2nd relay M motor 11 output path 12 1st means 13 2nd means 14 speed sensor

Claims (10)

[Claims] 1. A circuit device for an automobile, comprising at least one first switching means and at least one output path extending in parallel with an output line of the first switching means, the first switching means. The second switching means (R1) is provided in at least one output path (11) extending in parallel to the output line of (T), and in that case, the loss power of the second switching means (R1) is the above. A circuit device for an automobile, which is smaller than the power loss of the first switching means (T). 2. A second switching means (R1), which is operated according to a first signal (S1), the first signal being applied to the input of the first switching means (T). Circuit arrangement according to claim 1, characterized in that it is indirectly or directly related to the signal (S2). 3. The second switching means (R1) according to claim 1 or 2, characterized in that it is formed as a semiconductor element or as an electrically drivable mechanical switch (relay). Circuit device. 4. The first switching means is formed as a transistor (T), and the second switching means (R1) is energized so as to conduct to the transistor (T) for a selectable period. Open circuit, or if the conductivity of the transistor (T) exceeds a selectable conductivity threshold for a selectable period of time, it is connected in a conducting position. Two
Or the circuit device according to any one of 3 above. 5. Transistor (T) is used for open / closed loop control of the rotational speed of an electric motor (M), which is in particular a servomotor of an electric power steering system of a motor vehicle. The described circuit device. 6. A first means (1) for pulse width modulation.
2) is provided, the pulse width of the second signal (S2) is modulated by the first means, and the first switching means (T) is connected by the second signal (S2). Claim 2, characterized in that
The circuit device according to any one of 3, 4, or 5. 7. Circuit arrangement according to claim 6, characterized in that the pulse width of the second signal (S2) is selected according to the vehicle speed (V). 8. The second signal (S) is processed by processing a signal (V) relating to vehicle speed using a characteristic curve.
2) to modulate the pulse width of the first means (1
7. Circuit arrangement according to claim 6, characterized in that a second means (13) for driving 2) is provided. 9. The second switching means (R1) comprises:
Below the selectable first vehicle speed threshold (V1) is connected to a conducting position and above the selectable first vehicle speed threshold (V1) the second switching means (R1). Interrupts said output path (11). 9. The circuit arrangement according to claim 1, 2, 3, 4, 5, 6, 7 or 8. 10. On / off switching of said second switching means (R1) is actuated in a hysteretic manner, 1, 2, 3, 4, 5, 6, 7, 8 or 9.
The circuit device according to any one of 1.