JPH027242Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flywheel device for an internal combustion engine that can vary the moment of inertia added to the engine output shaft depending on the operating conditions of the engine.

Figure 1 (Service Bulletin No. 401, published by Nitsusan, November 1977) shows what has conventionally been commonly used as a flywheel for internal combustion engines. In the figure, 1 is an engine output shaft, 2 is a flywheel, 3 is a mounting bolt for integrally attaching the flywheel 2 to the engine output shaft 1, and 4 is a clutch disk (4) for taking out the engine output to the transmission. ) is the end face of the flywheel that is pressed. A ring gear 5 is attached to the flywheel 2 and engages with a starter pinion gear (not shown) to start the mesh engine.

However, in a system where the entire flywheel always rotates in unison with the engine output shaft, the moment of inertia of the flywheel added to the engine output shaft is constant, so when the engine is rotating at low speeds such as when idling, If the moment of inertia of the flywheel is increased to ensure driving stability in a vehicle, acceleration performance and fuel efficiency during acceleration will deteriorate, whereas if the moment of inertia of the flywheel is decreased, acceleration performance and fuel efficiency during acceleration will improve. However, there was a problem in that the operational stability at low speed rotation deteriorated, and one of these aspects had to be sacrificed to some extent.

In view of the above points, the present invention provides a flywheel device for an internal combustion engine that includes a first flywheel that is integrally attached to the engine output shaft, and a second flywheel that is rotatably attached to the engine output shaft. and a clutch disk which is provided to rotate together with the engine output shaft and to be elastically movable in the axial direction;
A fixed electromagnetic coil provided at an axial distance from the clutch disk, a clutch facing fixed to the second flywheel and cooperating with the clutch disk, and a rotation speed sensor for detecting the rotation speed of the engine. A comparator that compares the signal from the rotation speed sensor with a signal corresponding to the reference rotation speed, a throttle valve switch that detects that the throttle valve opening is above a predetermined angle, and a water temperature switch that detects the engine cooling water temperature. The control circuit includes a comparator and a coil energization control circuit that inputs signals from the throttle valve switch and the water temperature switch, and the coil energization control circuit energizes the electromagnetic coil intermittently. The flywheel and the engine output shaft are connected intermittently by an electromagnetic clutch depending on the engine operating conditions, and the moment of inertia of the engine output shaft is increased in the low speed range, and the moment of inertia of the engine output shaft is increased in the medium to high speed range or during acceleration. The above-mentioned problem is solved by making it possible to operate with a reduced moment.

Embodiments of the present invention will be described below with reference to the drawings. Fig. 2 is a sectional view of essential parts showing an embodiment of the present invention, Figs. 3a and 3b are a front view and an A-A sectional view of a return spring used in an electromagnetic clutch, and Fig. 4 is a control circuit diagram. It is a block diagram.

To explain the structure, 1 in FIG. 2 is the engine output shaft, 2a is the first flywheel, 2b is the second flywheel, and 3 is for integrally attaching the first flywheel 2a to the engine output shaft 1. A clutch disk (not shown) is pressed against the end face 4 of the first flywheel 2a, and engine output is taken out to the transmission. Further, a ring gear 5 attached to the first flywheel 2a meshes with a pinion gear (not shown) of a starter motor to start the engine.
6 is a ball bearing, the inner ring of which is in contact with the first flywheel 2a, and the outer ring of which is press-fitted into the second flywheel 2a. Therefore, the second flywheel 2b can freely rotate with respect to the engine output shaft 1 via the ball bearing 6. Reference numeral 7 denotes a clutch disk of an electromagnetic clutch, which is attached to the first flywheel 2a via a return spring 8 and rotates together with the engine output shaft 1. The return spring 8 has a plurality of fan-shaped cutouts 9 and bolt holes 10, 1 as shown in FIG.
1, and the first
It is connected to the flywheel 2a by bolts 12 passed through bolt holes 10, and to the clutch disk 7 by bolts 13 passed through bolt holes 11. A clutch facing 14 is attached to the contact surface of the second flywheel 2b with the clutch disk 7, and is fixed to the flywheel 2b by adhesive or rivets. Reference numeral 15 denotes a clutch electromagnetic coil, which is fixed to a coil case 16 forming a part of the magnetic circuit with a heat-resistant adhesive. The coil case 16 is fixed by bolts 19 to a rear plate 18 installed between an engine body 17 and a transmission (not shown), and the magnetic pole face of the coil case 16 and the engine side end face of the second flywheel 2b are opposed to each other with a slight gap a interposed therebetween. Reference numeral 20 denotes a hollowed out portion of the flywheel 2b provided to prevent shortening of magnetic flux.

In Fig. 4, 21 is a water temperature switch for detecting the warm-up state of the engine, and 22 is an ignition pulse or an electromagnetic pickup coupled to the ring gear 5, and the engine speed is detected by counting the number of pulses. A rotation speed sensor 23 is an F-V converter that converts the number of pulses into voltage, 24 is a throttle valve switch for detecting the load condition of the engine, and a water temperature switch 21 is used to set the cooling water temperature to a predetermined temperature (for example, 80°C). ), the throttle valve switch 24 outputs a high level signal when the throttle valve opening reaches a predetermined angle or more. 25 is an F-V converter 23
A comparator inputs a signal from the comparator 25 and a reference signal 26 corresponding to a predetermined rotation speed (for example, 1500 rpm), and outputs a high level signal when the engine rotation speed exceeds the predetermined rotation speed. 27 is a signal from the comparator 25 and a throttle valve. An OR gate 28 inputs a signal from the switch 24, and an AND gate 28 inputs a signal from the OR gate 27 and a signal from the water temperature switch 21. Engine operating conditions are detected by each element 21-28. 29 is a coil energization control circuit for intermittent energization of the electromagnetic coil 15;
The output signal of AND gate 28 is inverted by inverter 30 and input.

The above device operates as follows. First, when the engine is cold started, the water temperature switch 21 in FIG. 4 outputs a low level signal because the water temperature is still low. Therefore, the AND gate 28 outputs a low level signal regardless of the engine speed or load condition. The coil energization control circuit 29 is activated by a high level signal obtained by inverting this low level signal by the inverter 30, and energizes the electromagnetic coil 15. Then, 16-2b- in Figure 2
The magnetic flux passing through the magnetic circuit 7-2b-2b-16 causes the clutch disk 7 made of a ferromagnetic material to be moved to the second
A force acts to pull the flywheel 2b toward the flywheel 2b. Due to this electromagnetic attraction force, the return spring 8 is deformed as shown by the broken line in FIG. 3b,
Clutch disk 7 is clutch facing 14
and is coupled to the second flywheel 2b. Therefore, when the pinion gear (not shown) of the starter motor meshes with the ring gear 5 and drives the engine output shaft 1, the second flywheel 2b rotates together with the engine output shaft 1. At this time, the total moment of inertia of the flywheel added to the engine output shaft is the sum of the moments of inertia of the first and second flywheels 2a, 2b and the ring gear 5. Thereby, sufficiently stable operation can be ensured even in a relatively unstable combustion state during warm-up.

When the warm-up of the engine is completed, the signal from the water temperature switch 21 becomes high level, and the rotation speed sensor 22
The energization of the electromagnetic coil 15 is controlled by the signal from the throttle valve switch 24.

Even after warm-up is completed, the electromagnetic coil 15 continues to be energized because a large moment of inertia is required when the engine speed is relatively low. However, when the engine speed exceeds a predetermined speed, for example 1500 rpm, the signal from the comparator 25 becomes high level and passes through the OR gate 27 to the AND gate 28.
is input. As a result, a high level signal is output from the AND gate, and this signal is sent to the inverter 3.
Since the signal is inputted to the coil energization control circuit 29 as a low level signal via 0, the coil energization control circuit 29 cuts off the energization to the electromagnetic coil 15. Then, the clutch disk 7 shown in FIG. 2 is detached from the second flywheel 2b by the return spring 8, and the second flywheel 2b
Driving above. At this time, the total moment of inertia of the flywheel added to the engine output shaft is only the moment of inertia of the first flywheel 2a and ring gear 5, which is smaller than the total moment of inertia in the low speed rotation range. This improves acceleration performance and fuel efficiency during acceleration.

Furthermore, if the accelerator pedal is depressed greatly even when the engine speed is below 1500 rpm, the throttle valve switch 24 is activated and a high level signal is input to the OR gate 27, causing the outputs of the OR gate 27 and AND gate 28 to become high level. . Therefore, at this time, regardless of the engine speed, the electromagnetic coil 1
5 is cut off, and the moment of inertia of the flywheel applied to the engine output shaft is reduced as described above, resulting in an excellent sense of acceleration.

In addition to the structure shown in Fig. 2, it is also possible to embed the electromagnetic coil 15 in the second flywheel 2b and supply power using a slip ring and a brush, but the diameter of the slip ring should be larger than the diameter of the engine output shaft. As a result, there are many technical problems such as brush wear, spark generation, coil breakage due to vibration during high-speed engine rotation, and peeling of coil adhesive, which reduces reliability, manufacturing cost, etc. In view of this, it is practical to have a structure in which the electromagnetic coil 15 is fixed as shown in FIG.

As explained above, the flywheel device according to the present invention includes a first flywheel that is integrally attached to the engine output shaft, a second flywheel that is rotatably attached to the engine output shaft, and a second flywheel that is rotatably attached to the engine output shaft. a clutch disk that rotates with the shaft and is elastically movable in the axial direction; a fixed electromagnetic coil that is spaced from the clutch disk in the axial direction; and a second flywheel that is fixed to the flywheel. A clutch facing that works together with a clutch disk, a rotation speed sensor that detects the engine rotation speed, a comparator that compares the signal from the rotation speed sensor with a signal corresponding to a reference rotation speed, and a throttle valve opening that is set to a predetermined value. a control circuit that includes a throttle valve switch that detects that the engine cooling water temperature is above the angle, a water temperature switch that detects the engine cooling water temperature, and a coil energization control circuit that inputs signals from the comparator, the throttle valve switch, and the water temperature switch; Since the coil energization control circuit is configured to intermittently energize the electromagnetic coil, it is possible to change the moment of inertia of the flywheel in accordance with the operating conditions of the engine. In particular, since it is equipped with a water temperature switch and a rotation speed sensor, stable operation can be ensured when the engine rotates at low speeds such as during warm-up.Furthermore, it is equipped with a rotation speed sensor and a throttle valve switch, so when the engine is accelerating. Also, excellent responsiveness and fuel efficiency improvement effects are achieved during medium and high speed driving.

[Brief explanation of drawings]

Figure 1 is a sectional view showing a conventional flywheel.
Fig. 2 is a sectional view of essential parts showing an embodiment of the present invention, Figs. 3a and b are a front view of the return spring in Fig. 2 and its A-A sectional view, and Fig. 4 is a block diagram of the control circuit. It is a diagram. 1: Engine output shaft, 2a: First flywheel, 2b: Second flywheel, 3: First flywheel mounting bolt, 6: Ball bearing, 7: Clutch disk, 8: Return spring, 14: Clutch facing, 15: Electromagnetic coil, 16: Coil casing, 17: Engine body, 19: Coil casing fixing bolt, 21
~28: Engine operating condition detection means, 29: Coil energization control circuit.

Claims (1)

[Scope of utility model registration request] a first flywheel that is integrally attached to the engine output shaft; a second flywheel that is rotatably attached to the engine output shaft; and a second flywheel that rotates together with the engine output shaft and moves elastically in the axial direction. a clutch disk, a fixed electromagnetic coil axially spaced from the clutch disk, a clutch facing fixed to the second flywheel and cooperating with the clutch disk; A rotation speed sensor that detects the rotation speed, a comparator that compares the signal from the rotation speed sensor with a signal corresponding to a reference rotation speed, and a throttle valve switch that detects that the throttle valve opening is above a predetermined angle. The control circuit includes a water temperature switch that detects the engine cooling water temperature, a coil energization control circuit that inputs signals from the comparator, the throttle valve switch, and the water temperature switch, and the coil energization control circuit controls the energization of the electromagnetic coil. A flywheel device for an internal combustion engine that is characterized by intermittent operation.