JPS62216824A - Power unit mounting device - Google Patents

Abstract

PURPOSE:To prevent displacement and vibration of a power unit with an excel lent responsiveness when torque changes, by providing a means for detecting an input rpm to a transmission and controlling a mount property to a hard side for a prescribed period of time when an input rpm equal to or greater than a prescribed value is detected. CONSTITUTION:A control unit 21 is supplied with a detection signal from an rpm sensor mounted on an input shaft of a transmission. A change ratio compari son circuit in the control unit 21 compares the detected value to discriminate whether it is equal to or greater than a prescribed value. When it has a change ratio equal or greater than the prescribed value, a rotary valve 13 is closed to control a mount property of mount members 7A, 7B to hard for a prescribed period of time. With this arrangement, displacement and vibration of a power unit can be effectively prevented with an excellent responsiveness when a tran sient large torque change happens in changing a speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a mounting device for a power unit.

(Prior art) Recently, many automobiles (generally small cars) or PR
There has been a shift from the (front engine rear drive) system to the FF' (front engine front drive) system, and efforts are being made to reduce the weight of vehicles, mainly the vehicle body.

On the other hand, in order to respond to the increasing sophistication and diversification of user demands for automobiles, there is a trend toward lighter vehicle bodies and higher output from the engines themselves, such as the installation of high-performance engines and 4WD (four-wheel drive) power units. It is in. On the other hand, the above-mentioned improvement in interior comfort also requires low vibration and static image quality in the vehicle interior.

However, as mentioned above, converting the vehicle body itself to an FLM and installing a high-output engine creates a completely contradictory relationship from the viewpoint of reducing vibration and quietness in the vehicle interior as described above. In particular, the upper three engine parts are the largest sources of vibration and noise in the passenger compartment, so it is necessary to satisfy both of the above requirements and achieve low vibration and noise in the passenger compartment. In order to achieve this, the mounting structure itself for the entire drive unit including the engine, that is, the power unit, to the vehicle body must have an effective function that meets the above requirements.

Of course, the power unit generally employs a mounting structure that absorbs vibrations to some extent by mounting it on the vehicle body via a rubber member having a predetermined elastic coefficient.

However, such a mounting structure has the following drawbacks.

In other words, the rubber members at each support point as described above always have a constant elastic modulus (spring constant and damping constant), so they cannot adequately respond to torque fluctuations that change depending on the operating condition. In particular, transient drive torque fluctuations cause a large elastic displacement state, which causes the power unit supported by these to undergo large displacements, particularly in the longitudinal direction of the vehicle body when transient drive torque is applied, such as during acceleration or deceleration. The acting extremely low frequency (~101-(z
) or shock vibrations of low frequency (up to 30 Hz) that affect the vehicle body vertically and backwards. In addition, general high-frequency vibrations generated by steady rotation of the engine (engine speed 2 missing component)
The reduction effect itself cannot necessarily be said to be sufficient.

The above-mentioned jerk vibration and shock vibration are caused when the lowest order vibration is excited in the drive system and torsion system when transient drive torque is applied to the engine, especially during acceleration and deceleration of the vehicle.
This causes vibrations in the longitudinal direction of the vehicle body via the tires and the suspension, and at the same time the power unit receives the reaction force, causing a shocking input from the engine mount to the vehicle body, causing vibrations in the vertical and longitudinal directions of the vehicle body. form. Therefore, the jerk vibration is mainly caused by torque fluctuations in the drive system and torsional system, while the shock vibration is a combination of vibrations in the power unit and the vehicle system.

Therefore, in order to eliminate the drawbacks caused by the rubber mount, the power unit has two chambers, upper and lower, which are arranged on both sides of the rotation axis of the power unit, each filled with incompressible fluid, and a partition wall between the upper and lower chambers. The legs of the power unit are equipped with a pair of left and right mounts connected to each other, and in response to bounce vibrations, the lower chamber of the left mount and the royal chamber of the right mount are moved between the upper and lower chambers of the two mounts, which communicate with each other. Low bounce stiffness is achieved by the movement spring constant during bouncing and rolling, while the roll stiffness is increased by not allowing fluid movement between the two upper and lower chambers to deal with the roll vibration of the power unit. Power unit mounting devices have been proposed that are intended to prevent large displacements (low-frequency vibrations) of the power unit during engine operation, and also to reduce general engine vibrations (high-frequency vibrations) (for example, Japanese Patent Laid-Open No. 58 (Refer to Publication No.-161617).

However, although this conventional technology can certainly absorb the vertical vibration during bounce and prevent the lateral vibration caused by the displacement of the power unit during rolling, on the other hand, it is essentially aimed at increasing roll rigidity. To,
The high roll rigidity increases the transmission rate of the power unit's fluctuating torque due to engine rotation during acceleration, deceleration, etc. to the base, and it is difficult to alleviate vibrations, noise, etc. caused by this.

On the other hand, as another conventional example other than the above, for example, as disclosed in U.S. Pat. is configured to have one fluid chamber filled with incompressible fluid, and by communicating the fluid chambers of both mounts with a conduit having an orifice, transient torque fluctuations of the power unit are attenuated by the orifice. It's well known that it's the way it is.

By the way, with regard to this prior art, the present inventors aimed to reduce the roll rigidity of the above-mentioned mounting device by changing its basic configuration, that is, by changing the fluid chambers of the mount arranged on both sides of the rotating shaft of the power unit from each other. As a result of repeated studies on a configuration in which the two are connected through a conduit, it was found that due to the resonance phenomenon of the fluid in the conduit, the roll rigidity of the mounting device changes to the We found that the change occurs as shown in the figure. In other words, the spring constant representing the above-mentioned roll stiffness is: (1) In the low frequency range, because the fluid moves in the conduit, it is almost equal to the static spring constant K when the fluid chamber is communicated, and decreases as the frequency increases. and reaches the minimum value at the frequency fa.

(2) When the frequency increases beyond the above-mentioned minimum frequency fa, the inertial force of the fluid in the pancreatic duct increases, which is proportional to the square of the acceleration, making it difficult for the fluid to flow within the duct, so the frequency increases relatively rapidly. , is equal to the non-communicating spring constant (1+N)K (N is the expansion/movement spring constant ratio of the elastic wall in the mount) when the fluid chamber is not communicating at the frequency fe.

(3) Even after the above-mentioned frequency re has passed, it continues to increase and reaches its maximum value at the natural frequency of the fluid in the pancreatic duct "n".

(4) From the above 5 natural vibration loss fn, in the high frequency range, it decreases as the frequency increases, and asymptotically approaches the bipedal non-communicating spring constant (1+N)K in a state where the fluid does not flow in the conduit.

Considering the above conclusion, in the configuration of the prior art described in 1., the roll stiffness can be reduced when the roll vibration frequency of the power unit is in the low frequency range, but in the high frequency range, the roll stiffness is as high as when it is not connected. Therefore, it is not always possible to keep the roll stiffness low.

Therefore, in order to solve this drawback, the present inventors provided a pair of mounts filled with incompressible fluid to elastically support the power unit on the base on both sides of the rotation axis of the power unit. In addition, a conduit is provided to communicate the fluid chambers of both mounts to allow fluid movement and to correlate pressure changes in both fluid chambers, and a portion of the wall of each fluid chamber is configured to respond to changes in fluid chamber pressure. an elastic membrane deformation restraining means for selectively preventing deformation of the elastic membrane; He previously proposed a power unit mounting device equipped with an actuator for actuating the means (Japanese Patent Application No. 60-60).
8306).

According to the configuration of the present invention, during roll vibration of the power unit, in a high frequency range where fluid does not move in the conduit due to an increase in vibration frequency, the elastic membrane deformation restraining means is introduced by introducing negative pressure into the negative chamber of the actuator. When the function of the mount is stopped and the elastic membrane is allowed to deform, changes in the volume of the fluid chamber of each mount are absorbed by the deformation of the elastic membrane, making it possible to maintain low roll rigidity.

In addition, in the low frequency range, if the negative pressure chamber of the actuator is opened to the atmosphere and the deformation of the elastic membrane is prevented by the elastic membrane deformation restraint means, the change in volume of the fluid chamber of each mount will be caused by the fluid passing through the conduit. The roll stiffness can be kept low by taking advantage of the continuous effect area where the roll spring constant is minimized, and the spring characteristics during roll can always be made soft. It turns out.

Furthermore, the bipedal elastic membrane deformation restraining means utilizes the negative pressure of a negative pressure source such as the intake negative pressure in the engine intake pipe to introduce negative pressure into the negative chamber of the actuator or to introduce the negative pressure into the atmosphere in the negative chamber. Since it is activated by opening, it is possible to reliably avoid activation of the elastic membrane deformation restraining means with a large power using the negative pressure as a pressure source.

(Problem to be solved by the invention) However, if low roll stiffness is always obtained regardless of the operating state of the engine, a large torque may be generated transiently due to a change in gear ratio, especially when changing gears. In the case of fluctuations, this is rather a negative result, and on the contrary, it causes large displacements.

Therefore, it is necessary to use some means to detect the shift state where the torque fluctuation is particularly large as described above, and to make the rigidity (mount characteristics) high (hard) in the detected state.

(Means for Solving the Problems) The present invention was made for the purpose of solving the above problems. In a mounting device for a power unit mounted on a vehicle body via a variable type mounting means, a rotation speed detection means detects a manual rotation speed inputted from the engine to the transmission mechanism, and a rotation speed detection means based on a detected value of the rotation speed detection means. The apparatus is further provided with a mount characteristic control means for controlling the mount characteristic of the mount means to the hard side within a predetermined periodical when a change in the input rotation speed equal to or greater than a predetermined set value is detected.

(Function) According to the above means, when transient and large torque fluctuations occur during gear shifting, the mount characteristics specified by the spring constant or damping constant are set to the hard (highly rigid) side based on the input rotation speed to the transmission. As a result, displacement and vibration of the power unit at the time of the torque fluctuation can be effectively prevented with particularly good response.

(Embodiment) FIGS. 2 to 4 show a mounting device for a power unit y I according to a first embodiment of the present invention.

First, FIG. 2 shows the system structure of the entire system of the above-mentioned embodiment, and in the figure, the reference numeral 1 indicates a vehicle body frame on which the power unit 2 is mounted, for example, in the engine room on the front side of the vehicle. The power unit 2 includes, for example, a horizontally mounted engine body 4 and a transmission 5 (see FIG. 3) integrally connected to the output shaft side of the engine body 4, and the transmission 5 side of the power unit 2. A pair of mounting brackets 3A are provided on the vehicle body frame I via a rubber mount portion (not shown), and on the engine main body 4 side, extending from a lower position to both left and right sides.

3B and specified by the spring constant or damping constant described below)・a pair of variable characteristic type mount members (corresponding to the mounting means in the claims) 7A, 7B It is mounted to the vehicle body frame l.

The mount parts 17A and 7B each have a cylindrical housing 8 fixed to the vehicle body frame 1 and open at both upper and lower ends, and seal the upper end opening of this housing 8, and are attached to the mounting brackets 3A and 3B. Rubber walls 10A and IOB that have a predetermined elasticity and are connected via sleeve-shaped fastening bolts 9A and 9B, and flexible elastic membranes +1A, 11B; the rubber wall 10A;
It is formed from movable plates 12Δ, 12B that partition the sealed space in the housing 8 formed by the IOB and the elastic membranes 11A, 11B into two upper and lower chambers, and is defined by the movable plates hl 2A, 12B. The upper chamber side of the internal space of the casing 8 is communicatively connected to each other by conduits 1 and 1 with rotary valves 13 interposed therebetween, while the lower chamber side defined by the movable plates 12A and 12B is connected to the lower chamber side defined by the movable plates 12A and 12B. is a stopper portion 15A that holds the movable plates I 2A and 12B on their periphery so that they can move up and down.
, damper orifice formed in 15B +6A, 1
6B.

An incompressible fluid 20 is sealed in the lower chamber, the royal chamber, and the conduit 14, respectively.

On the other hand, the low-return valve 13 is driven by an electromagnetic solenoid, and controls (opens and closes) the communication state between the pair of mount members 7A and 7B according to the engine operating state. This control signal is supplied from a control unit 21 which will be explained in detail later.

Furthermore, the symbols 30Δ and 30B are the respective mounting members 7A,
Negative pressure actuators 30Δ and 30B are shown at the bottom of 713, and these negative pressure actuators 30Δ and 30B are connected to the negative pressure chambers 32A and 32A in the main body cases 31Δ and 31B, respectively.
32B is divided into two upper and lower chambers by diaphragms 33A and 3313, and the upper and lower chambers are communicated with each other via communication passages 35 and 36, while the diaphragms 33A and 33B are equipped with rods. Plunger members 37A, 3713 are supported, and the upper ends of the plunger members 37A, 37B are connected to the main body case 31.
A, 31B protrudes upward from the upper surfaces of the mount members 7A, 7B and faces the elastic membranes jlA, IIB of the mounting members 7A, 7B, and the protruding ends have the elastic membranes r! X+IA, 11!3
Circular position regulating plates 39A and 39B that can come into contact with are provided. In addition, the main body cases 31A and 31B
Coil springs 40A, 40B are compressed between the upper surface of the plunger member 37A, 37B, and the coil springs 40A, 40B cause the plunger member 37 to
A.

37B is always in the downward direction (the position regulating plate 39Δ,
39B is separated from the elastic membranes 11A and IIB)
is energized by And the plunger member 37A
, 37B are positioned at the lowest end, the position regulating plates 39A, 39B and the elastic membranes 11A, 1
The distance from 1B is the above stopper plate l 5A, 15B
and the elastic membranes IIA, IIB to allow deformation of the elastic membranes 11A, IIB, while on the other hand, the planojaffi! 1. , l' 37 A ,
37 B is the above coil spring ・10A, 40B A; When it rises against the 1 force, the above position regulation play)・39
A and 39B act to press the elastic membrane 7 against the upper flood stopper plates 15A and 15B to prevent its deformation.

The communication passage 35 in the lower part 1 is connected to a negative pressure source (negative pressure pump) 45 via a check valve 42 and an accumulator 43 by a negative pressure pipe 11. Further, the second communication path 36 is configured to be selectively communicated with the negative pressure pipe 41 or the atmosphere introduction portion 47 via an electromagnetic switching valve 46. The operating state of this electromagnetic switching valve 1G is controlled by a shift control unit 21, which will be described later.

On the other hand, as shown in FIG. 3, an input shaft 50 of the transmission 5 has a rotation speed sensor 5 for detecting its rotation speed. is provided, and the detected value of the rotation speed sensor 51 is input to the control unit 21.

The control unit 21 is composed of, for example, a microprocessor (CPTJ), a memory (r (OM and RAM)), and an interface circuit.

The control unit 21 compares the rate of change a of the detected value of the rotation speed sensor 51 attached to the input shaft 50 of the transmission 5 with a predetermined set value al, and determines that the rate of change is equal to or higher than a certain value. It has a change rate comparison circuit (not shown) that detects this, and the negative pressure actuators 3'OA, 3
0B and rotary valve 13 are to be controlled as shown in FIG. The specific content of this control will be described in detail below.

Next, the control operation of the negative pressure actuators 30A, 3'OB and the rotary valve 13 by the control unit 21 will be described in detail with reference to the flowchart of FIG. 4.

First, the starter switch (ignition switch) SW
After the start of the control operation with the ON of , step 1.
Bu q, at 1'no pano・no hill 1 umbrella μ age M [
'l (Eso・zo・) Iα II-Illusion, Yu!
y3), and in the case of YES, the process proceeds to step S2 and the above-mentioned negative pressure actuators 30A, 3
After maintaining the 0B in the inoperative state and the rotary valve 13 in the closed state, a timer (t1 seconds) corresponding to the cranking time is set in step S3, and this state is indicated as FLAG 1, and the process proceeds to step S4. Also,
No in step SI above.

In this case, the process directly advances to step S4. The non-operating state of the negative pressure actuators 30A and 30B is controlled by a control signal from the control unit 21 to control the electromagnetic switching valve 46.
Switch the negative pressure actuator 3 to the negative pressure pump 45 side.
This is done by communicating the lower chamber side of the QA, 3013 with the negative pressure pump 45. Therefore, in this state, the position regulating plate 39A of the negative pressure actuators 30A, 30B.

3913 is positioned at the lowest end by the biasing force of the coil springs 10A and 40B, and the elastic membrane 1.1A is positioned at the lowermost end.

+113 becomes free, while the above low revalve 13
The closed state prevents fluid movement between the mount members 7A and 7B, resulting in hard mount characteristics (cranking region in FIG. 6).

Next, in step S4, the current operating state is PL, 8G1.
If it is determined that the cranking is still possible, the process proceeds to step S5, where the starter switch Sw is shifted from ON to OFF.
In other words, confirm that the engine has started, and then proceed to step S. Then, it is determined that the cranking time [1] has elapsed, that is, the start of the engine has been completed.''2, the process proceeds to the next step S7, and the timer set r'LAG is reset to 0. Above step S5. The determination of S is repeated until the determination result becomes YES.

When the operation of step S7 is completed, the process further proceeds to step S8, where the differential value of the rotational speed of the above-mentioned transmission shaft 50 is inputted, and it is determined that the rate of change a is larger than the predetermined value a1. After making the judgment, the judgment result is Y.
In the case of ES, the process directly proceeds to step S, and the negative pressure actuators 30A, 3 are activated as in the case of step S2 above.
The mount characteristics of the mount members 7A and 7B are controlled to the heart by setting the 0B in the inoperative state and the low-return valve 13 in the closed state (Fig. 6, speed change area). Further, in step S, the rate of change a of the manual rotation speed is set to a predetermined value a1.
If it is smaller (NO), the process advances to step S11.

Then, in step SIl, it is determined whether the intake pipe negative pressure B of the engine is larger than the first reference value B, which partitions the operating range of the engine shown in FIG. 6, and smaller than the second reference value B, If the answer is YES (meaning an idling state in this case), the process proceeds to step Sa2, and if the answer is No (meaning a steady running state in this case), the process proceeds to step S13.

In step S1ffi, first, the electromagnetic switching valve 46 is switched to the atmospheric side to control the negative pressure actuator 3.
Atmospheric pressure is introduced into the lower chamber side of 0A, 30B to operate the negative pressure actuators 30A, 30B. U-1 raises its position regulating plates 39A, 39B and moves the mounting member 7A.
, 7B while restraining the displacement of the elastic membranes 11A and 11B, the lower valve 13 is opened and both the mounting members 7A,
7 Allow fluid movement between the mount chambers of B to soften the mount characteristics (idling area in Figure 6). This effectively absorbs and damps vibrations during idling.

On the other hand, in step S13, the negative pressure actuator 3
Due to non-operation of 0A and 30B, the position regulating plate 39
A, 39B descends to the elastic membrane 11A.

11B is freely controlled, while the low re-valve 13
will be released. As a result, the above mounting member? A, 7B
No fluid movement occurs between the two mounting chambers, and the vibrations at this time are absorbed by the deformation of the elastic membranes 11A and IIB.
The mount characteristics are controlled to a normal state between soft and hard (steady running region in Figure 6). As a result, secondary vibration components caused by the engine speed that occur during steady operation are effectively absorbed and attenuated.

The relationship between the vibration component and the spring constant, for example, corresponding to each of the engine operation control regions described above is shown in the characteristics shown in FIG. The optimum spring constant rlI(:+:
1. This means that

Next, the flowchart of FIG. 5 shows the control operation of the power unit mounting device according to the second embodiment of the present invention.

In this second embodiment, steps 89 to 5111 in the flowchart of FIG. 4 are replaced with step S9 shown in FIG.
, S13-S,. The program was changed to B, and all other parts are the same as the program in Figure 4.

That is, if it is determined in step S8 that the rate of change a of the input rotation speed of the transmission manual shaft is larger than the predetermined value a1 (YES), first, in step S9, the value b1 of the input rotation speed N at that time is determined. remember. Then, the process further proceeds to step SI3, and it is repeatedly determined whether or not the rate of change dN/dt of the human rotational speed N after a predetermined period of time has elapsed is greater than a predetermined value al.

Then, if the result is NOl, that is, the rate of change has decreased, the process proceeds to step S14, and the width of the change,
That is, it is determined whether or not IN-b,1 is greater than a predetermined value. If NO, the process returns to step S1, while if YES, it is regarded as a gear change operation and the process shown in FIG. 4 is performed. Step S,,S,. The same operations as (steps S 2 , . . . S +e) are performed to hardly control the mount characteristics of the mount members 7 A and 7 I3 within a predetermined time (11 seconds). As a result, the gear shift state can be detected with good responsiveness from the change in the rotational speed of the transmission input shaft, and the gear shift state can be efficiently shifted to the corresponding mount characteristics.

(Effects of the Invention) As explained above, the present invention mounts a power unit composed of an engine and a transmission mechanism to a vehicle body through a mounting means with variable mounting characteristics specified by a spring constant or a damping constant. A mounting device for a power unit comprising: a rotation speed detection means for detecting an input rotation speed input from the engine to the transmission mechanism; and a change in the input rotation speed by a predetermined set value or more based on a detected value of the rotation speed detection means. The present invention is characterized in that a mount characteristic control means is provided for controlling the mount characteristic of the mount means to the hardware side within a predetermined period when the mount characteristic is detected.

Therefore, according to the present invention, transient and large)
・When torque fluctuation occurs, the mount characteristics specified by the spring constant or damping constant are controlled to the hard (high rigidity) side based on the input rotation speed to the transmission. Displacement and vibration of the power unit are particularly responsive and effectively prevented.

[Brief explanation of drawings]

Fig. 1 is a diagram corresponding to claims of the present invention, Fig. 2 is a block diagram showing the overall system configuration of a mounting device for a power unit according to a first embodiment of the present invention, and Fig. 3 is a diagram showing the entire system configuration of a mounting device for a power unit according to a first embodiment of the present invention. A partially cutaway sectional view of the transmission section, FIG. 4 is a flowchart showing the control operation of the control unit i of the device of the same embodiment, and FIG. 5 is a flow chart showing the control operation of the power unit mounting device according to the second embodiment of the present invention. The flowchart shown in FIG. 6 is a mount characteristic diagram of each of the embodiments described above. 1...Vehicle body 2, 4, power unit 4...Engine body 5...Transmission 7A, 7B...Mount member 13...Lower valve 21...Control unit 30A, 30B... Negative pressure actuator 46...
Solenoid switching valve 50... Transmission input shaft 51... Rotation speed sensor

Claims (1)

[Claims] 1. In a mounting device for a power unit in which a power unit constituted by an engine and a transmission mechanism is mounted on a vehicle body via a mounting means of a variable mount characteristic type specified by a spring constant or a damping constant, an input signal from the engine to the transmission mechanism is mounted. a rotational speed detection means for detecting an input rotational speed; and a rotational speed detection means for detecting an input rotational speed of the mounting means; A mounting device for a power unit, characterized in that a mounting characteristic control means for controlling the hardware side is provided.