JPS59102622A - Power unit support device - Google Patents

Abstract

PURPOSE:To prevent oscillation by applying the oscillation resulting from the torque variation of an engine and the pulsation of an inverse phase to the intra- chamber non-compression fluid of an elastic body between a car body and a power unit. CONSTITUTION:Support units 16 and 17 that support a power unit 15 on a car body have elastic bodies 19, 20, 22, and 23 and chambers 24 to 27 are formed in each of the elastic bodies. Each of the chambers 24 to 27 is connected to the respective chambers 30 and 33 of bellows 29 and 32 through pipes 28 and 31, respectively. Plungers 35 and 36 are connected to each of the belows 29 and 32 and each of the plungers 35 and 36 is engaged with the cam surface 38 of a cam 37, separated by 180 degrees mutually. The cam 37 is secured to a driving shaft 39 and the driving shaft 39 is connected to a crank shaft through a small pulley 40, belt 41, and large pulley 42. In addition, each of the chambers 24 to 27, 30 and 33 and pipes 28 and 31 are filled with non-compression fluid. Then the cam 37 is rotated by the rotation of the crank shaft and the oscillation resulting from the explosion force of an engine and the pulsation of an inverse phase are applied to the said non-compression fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support device for a power unit, and more particularly to a support device for supporting a power unit including an internal combustion engine, a transaxle, and a vehicle body on a vehicle body.

As a conventional support device for a rotating machine, one disclosed in, for example, U.S. Pat. No. 4,154,206 is known. This supporting device for a rotating machine includes an elastic body 3 interposed between a vehicle body 1 and an engine housing 2, and a chamber 4 is formed in the elastic body 3. This room 4
communicates with a chamber 9 defined by a cylindrical casing 6, an elastic wall 7, and a rigid plate 8 via a passage in the piping 5. These chambers 4.9 and the passages in the pipe 5 are filled with liquid. The elastic wall 7 is connected to a rod 10 that slidably passes through the housing 2, and the rod 10 is connected to a cam surface 12 of a cam 11 that rotates in synchronization with a crankshaft (not shown) of the engine. engaged. The cam surface 12 is composed of a flat part and a protrusion. When the protrusion of the cam surface 12 presses the lot 10, the lot 10 moves to the left in FIG. 1, presses the wall 7, and closes the chamber 9. Increase the pressure of the liquid inside. On the other hand, when the flat portion of the cam surface 12 engages with the rod 10, the rod 10 moves to the right in the figure due to the restoring force of the wall portion 7, and the hydraulic pressure in the chamber 9 decreases.

By the way, the support device described in the above-mentioned U.S. Pat. When used as a support device for a reciprocating engine, the rotating body that produces unbalanced mass is a connected body such as a piston, connecting rod, or crankshaft.
The acceleration reaches its maximum value at the top dead center and bottom dead center of the piston (Fig. , the figure shows a piston in one of the cylinders of a four-cylinder, four-cycle reciprocating engine). Therefore, the excitation force transmitted from the engine housing 2 to the elastic body 3 reaches its maximum value at the top dead center and bottom dead center of the piston, and the volume of the chamber 4 decreases or increases. When the piston reaches the bottom dead center and the top dead center, the rod 10 must be engaged to lower or increase the hydraulic pressure in the chamber 9.

However, regarding the vibrations generated in the power unit composed of the engine and the transaxle, it is necessary to prevent not only vertical vibrations caused by the unbalanced mass of pistons, but also vibrations caused by the explosive force generated in each cylinder. This is important, and conventional support devices have the problem of not being able to prevent vibrations caused by the explosive force generated in each cylinder. In other words, ignition and explosion occur in each cylinder of the power unit after the compression stroke ends, and the explosive force that acts on the top surface of the piston and is transmitted as output torque to the crankshaft via the connecting rod is generated at a predetermined angle after the piston passes through top dead center. Although it reaches its maximum when the motor rotates and is reduced by the rotating inertial mass of the flywheel, the output torque still fluctuates. Therefore, the present invention is directed to vibrations caused by torque fluctuations corresponding to the explosive force generated in each cylinder of the engine in an incompressible fluid inside an elastic body interposed between a vehicle body and a power unit equipped with an engine. The purpose of this is to prevent vibrations caused by the explosive force generated in each cylinder by providing pulsations with a phase opposite to that of the cylinder.

Hereinafter, this invention will be explained based on the drawings.

FIG. 3 is a diagram showing a first embodiment of the present invention, and the configuration will be explained first. Reference numeral 15 denotes a power unit composed of an engine and a transaxle, and in this embodiment, a 4-cylinder, 4-cycle engine is used. The power unit 15 is supported by the suspension members configuring the vehicle body via support units 16 and 17, and the support unit 16 is supported by elastic bodies 19. It has 2o. on the other hand,
The support unit 19 also has an elastic body 22 and a collar connected to the upper and lower surfaces of a bracket 21 fixed to the side wall of the power unit 15, respectively. .27 are formed respectively. The chambers 24 and 27 communicate with each other via passages in the piping 28 and are connected to a chamber 30 defined by the bellows 29.
The chambers 5.26 communicate with each other via passages in the pipe 31 and also with the chamber 33 defined by the bellows 32. The bellows 29 and 32 have their radially outer ends fixed to the case 34, respectively.
Their radially inner ends are connected to plungers 35, 36 which slideably pass through the case 34. The plungers 35, 36 are engaged with cam surfaces 38 of a cam 37 rotatably housed in the case 34 at a distance of 180 degrees from each other, and the cam surfaces 38 have one protrusion. cam 3
7 is fixed to a drive shaft 39, and the drive shaft 39 is connected to a crankshaft via a small pulley 40, a belt 41, and a large pulley 42. Since the diameter d1 of the small pulley 40 is selected to be 2 of the diameter d of the large pulley 42, the drive shaft 39 rotates twice during one rotation of the crankshaft, and the cam 37
makes the plungers 35 and 36 reciprocate twice. The cam 37 is located at a position where, when an explosion occurs in any cylinder of the power unit 15, the protrusion of the cam surface 38 presses the plunger 35 or a to reduce the volume of the chamber 30 or 33 in the bellows 29 or 32. It is fixed to the drive shaft 39, and the reduced volume of the chambers 3o and 33 is reduced by the power unit 1.
Chambers 24, 25, 26, 27 due to roll vibration occurring in 5
approximately equal to the amount of change in volume. The above bellows 29.32, case 34, plunger 35.36, cam 37, drive shaft 3
9, the small pulley 40, the belt 41, and the large pulley 42 constitute a pulse pressure generating means 43 as a whole. Also, room 2
4.25.26.27.30.33 and by piping, 31
The passageway is filled with an incompressible fluid.

Next, the effect will be explained. First, power unit 15
When the engine is activated, explosions occur in each cylinder in sequence, and the power unit 15 generates explosive force twice per crankshaft rotation. Therefore, the crank angle θ of the crankshaft and its sine value are as shown in FIG. 4a, but the power unit 15
The explosive force generated when the piston in either cylinder is at the top dead center as shown in Fig. This occurs when the vehicle moves a predetermined angle after passing through the position shown. This explosive force is transmitted to the crankshaft via the piston, connecting rod, etc. as torque fluctuations in the output torque, and its reaction force is transmitted to the cylinder block of the power unit 15. In particular, the horizontal component force causes roll vibration in the power unit 15 in the direction of arrow A in Figure 3, but the roll angular acceleration of this roll vibration causes the generation of force as shown in Figure 4C. Maximum value occurs at times. Therefore, roll vibrations as shown in FIG. 4d occur in the power unit 15, which roll vibrations displace the support units 16, 17 with the same period. During the period when the curve shown in FIG. 4d has an upward slope, the volume of the chambers 24 and 27 increases and the volume of the chambers δ and 26 decreases, and during the period when the curve in the same figure has a downward slope, the volume of the chambers U, 26 decreases. The volume of chamber 5.27 decreases and the volume of chamber 5.26 increases. FIG. 4e shows the change in volume of chamber U. on the other hand,
The drive shaft 39 rotates at twice the angular velocity of the crankshaft, and when the explosive force shown in FIG. The volume of the chambers 30 and 33 of .32 decreases twice per crankshaft rotation when explosive force is generated, thereby generating pulsation. As a result, the difference between the amount of change in the volume of the chamber 24.27 and the amount of change in the volume of the chamber δ is absorbed by the amount of change in the volume of the chamber 30.33, and the roll rigidity of the support unit 16.17 is reduced. Therefore, it is possible to prevent large roll vibrations of the power unit 15, particularly vibrations at the secondary frequency of rotation of the crankshaft that occur during idling, from being transmitted to the vehicle body.

Note that when the support unit 16, 17 and the pulsating pressure generating means 43 are very close to each other, the protrusion of the cam surface 38 simultaneously generates the explosive force and the plunger 35 as described above.
, A can be set to press, but support unit 1
6. When 17 and the pulse pressure generating means 43 are separated,
Considering the propagation speed of pressure, the timing at which the protrusion on the cam surface presses the plunger 35 and 36 is advanced by a certain period of time (the fourth
(see figure f). Furthermore, although the first embodiment described above is applied to a 4-cylinder 4-stroke engine, when applied to other types of engines, the large pulley Tsukuda and the small pulley 4
Change the diameter ratio of 0 as appropriate.

Furthermore, it goes without saying that by changing the communication between the chambers 24.5, 24.5, 27, it is possible to cope with vibrations in the vertical direction.

FIG. 5 is a diagram showing a pulse pressure generating means 44 used in the second embodiment of the present invention, and since the configuration other than the pulse pressure generating means 44 is the same as that of the first embodiment, it corresponds to that in the first embodiment. Use signs. A case 45 defines a chamber 50.51 together with a rubber diaphragm 46.47 and a piston 48.49, and the chamber 50.51 communicates with the pipe 31 and the Hanyu passage.

A camshaft 52 that constitutes the engine valve mechanism of the power unit 15 passes through the case 45 in a freely rotatable manner.
A cam 53 is fixed to the cam shaft 52. Konocam 5
3 has a cam surface 54 formed with four protrusions, into which the radially inner ends of pistons 48, 49, which pass through the case 45 at a distance of 1800 degrees from each other, engage. The radially outer ends of the pistons 48, 49 are respectively fixed to the radially curved inner ends of diaphragms 46, 47, and the radially outer ends of the diaphragms 46, 47 are respectively fixed to the case. In addition, the case 45 and the piston 48.
Since springs 55 and 56 are compressed between the outer ends of the camshaft 52 and the outer ends of the camshaft 52, the chamber 5
0.51 each scales 4 times. Since the camshaft 52 of a 4-cylinder 4-cycle engine rotates once per 2 revolutions of the crankshaft, the chamber 50.51 expands and contracts twice per 1 revolution of the crankshaft, and changes in the volume of the chambers 24, 25, 26, 27 are absorbed. Ru. Therefore, it is possible to prevent the occurrence of roll vibration at the secondary rotational frequency of the crankshaft. The aforementioned case 45, diaphragm 46, 47, piston 48, 49, cam 53, and spring 55, 56 collectively constitute the pulsating pressure generating means 44.

FIG. 6 is a diagram showing the pulse pressure generating means 57 used in the third embodiment of the present invention, and the same reference numerals are used for the same components as in the first embodiment. A camshaft 52 that constitutes an engine valve mechanism passes through one end of the case 58, and a cam 59 is fixed to the camshaft 52. On the other hand, case 5
The other end of the sun is connected to the diaphragm 62 together with the lid 60.6I.
．． 63 is held between the lid 60.61 and the diaphragm 6.
2.63 define chambers 64.65 which communicate with the passages of the pipes 31.28, respectively. diaphragm 62
．． One end of a rod 66, 67 is fixed to 63,
The other ends of the rods 66 and 67 are rotatably connected to one end of a substantially dogleg-shaped arm 69 rotatably supported by a shaft 68, and the other end of the arm 69 is biased by a spring 70 to connect to a cam. It is constantly engaged with the cam surface 71 of 59.

Since the central portion of the arm 69 is swingably supported by the case 58, one end of the arm 69 reciprocates in the vertical direction in FIG. 6 as the cam 59 rotates, thereby expanding and contracting the chambers 64 and 65. Therefore, changes in the volume of the chambers 24, 25, 26, 27 are absorbed by the expansion and contraction of the chambers 64, 65, and roll vibration is prevented. The aforementioned case 58, cam 59, and lid 60
．． 61, diaphragm 62.63, rod 66.67,
The shaft 68, the arm 69, and the spring 70 constitute the pulse pressure generating means 57 as a whole.

According to this embodiment, the diaphragm 6 can be adjusted by selecting the lever ratio of the arm 69 without increasing the lift of the cam 59 unnecessarily.
There is an advantage that the amplitude of 2.63 can be increased.

As described above, according to the present invention, the power unit support device includes an elastic body interposed between the vehicle body and the power unit including the engine and formed with a chamber filled with incompressible fluid; The pulsating pressure generating means applies pulsations to the incompressible fluid in the room in synchronization with the engine crankshaft, and the pulsating pressure generating means generates vibrations caused by explosive force generated in the power unit after the compression stroke of the engine and a phase opposite to the vibrations caused by the explosive force generated in the power unit after the compression stroke of the engine. Since the pulsations are applied to the incompressible fluid in the room, it is possible to prevent vibrations caused by the explosive force of the engine. Furthermore, in each of the above embodiments, the chamber of the elastic body constituting the support unit and the expanding/contracting chamber of the pulsating pressure generating means communicate with each other through the piping passage, making it possible to completely enclose the incompressible fluid. This also has the effect of preventing leakage to the outside.

[Brief explanation of the drawing]

Figure 1 is a front sectional view showing a conventional support device, Figure 2a
'-c is a graph explaining vibrations caused by the unbalanced mass of the power unit, FIG. 3 is a front sectional view showing the first embodiment of the present invention, and FIGS. 4 a to f are roll vibrations caused by the explosive force of the power unit. 5 is a front sectional view showing a part of the second embodiment, and FIG. 6 is a front sectional view showing a part of the third embodiment. +5---Power unit, 19.20.22.23---One elastic body, 24-27
-----Chamber, 43.44.57---Pulse pressure generating means. Patent applicant: Nissan Motor Co., Ltd. Patent attorney Agagun Part 1

Claims (1)

[Claims] an elastic body interposed between a vehicle body and a power unit including an engine and formed with a chamber filled with an incompressible fluid;
In a power unit support device comprising a pulsating pressure generating means for pulsating an incompressible fluid in a room in synchronization with a crankshaft of an engine, the pulsating pressure generating means causes an explosion that occurs in the power unit after a compression stroke of the engine. A support device for a power unit characterized by applying pulsations in a phase opposite to vibrations caused by force to an incompressible fluid in a room.