JPS61215850A - Tensioner apparatus in laying transmission apparatus for internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce the dimension of all the apparatus by arranging an autoadjustor into the space formed between a driving wheel and a driven wheel for auxiliary drive. CONSTITUTION:Onto the loosening side of a transmission belt 5, a driven wheel 6 for auxiliary drive which is supported onto an engine body E in eccentricity to oneside from the cylinder axis-line L-L of the engine body E which passes through the center of a crankshaft is laid. Further, on the driven wheel 6 and a driving wheel 3, a tension pulley 8 arranged nearly directly over the driving wheel 3 is press-attached onto the outside surface on the loosening side of the transmission belt 5. Further, outside the tension pulley 8, an autoadjustor A connected to the tension pulley 8 for applying a certain tension onto the transmission belt 5 is arranged into the space formed between the driving wheel 3 and the driven wheel 6 for auxiliary drive. With such constitution, the dimension of all the apparatus can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Purpose of the Invention (1) Industrial Field of Application The present invention automatically applies constant tension to an endless transmission band suspended between a driving wheel and a driven wheel supported by an engine body in an internal combustion engine. The present invention relates to a tensioner device for a wrap-around transmission.

(2) Conventional technology An endless transmission band is suspended between a driving wheel integrated with the crankshaft and a driven wheel integrated with the valve camshaft, and on the loose side of the transmission band,
A tensioner device for a timed winding transmission in an internal combustion engine is conventionally known (Japanese Unexamined Patent Publication No. 50-208
(See Publication No. 251).

(3) Problems to be Solved by the Invention By the way, in such a timed winding transmission device, the winding angle of the transmission band with respect to the driving wheel and the driven wheel is increased to reduce the load on the meshing teeth of these wheels, thereby increasing the transmission efficiency. In addition to increasing the transmission band's lifespan, it is also required to reduce the space occupied by the wrapped transmission device as much as possible.

It is an object of the present invention to provide a novel tensioner device for a timed wrap transmission in an internal combustion engine that can satisfy all of these requirements.

B0 Structure of the Invention (1) Means for Solving Problems In order to achieve the above-mentioned object, the present invention provides a drive wheel integrated with a crankshaft supported at the lower part of the engine body and a valve train cam supported at the upper part of the engine body. In a timing wrap transmission device for an internal combustion engine in which an endless transmission band is suspended between a driven wheel integral with a shaft, a cylinder axis L of the engine body E passing through the center of the crankshaft is located on the slack side of the transmission band. - An auxiliary drive driven wheel supported by the engine body is suspended to one side from L, and between this driven wheel and the drive wheel, the drive wheel is attached to the outer surface of the loose side of the transmission belt. A tension pulley disposed approximately directly above is pressed against the tension pulley, and a space formed between the drive wheel and an auxiliary drive driven wheel outside the tension pulley is provided with a constant tension applied to the transmission band. An auto adjuster connected to the tension pulley is provided.

(2) Function According to the above configuration, the tension pulley is pressed against the transmission band and applies a constant tension thereto, and the transmission pair can be wrapped around the driving wheel and the driven wheel at a large angle. The space occupied by the transmission band is small.

(3) Embodiments Hereinafter, embodiments in which the device of the present invention is implemented in a DOHC type four-stroke internal combustion engine will be described with reference to FIGS. 1 to 6.

In the figure, one end surface of the engine body E of the internal combustion engine has
A timing winding transmission device T is provided which interlocks the crankshaft 1 and a pair of valve drive camshafts 2 of the valve drive mechanism. In other words, the crankshaft 1 supported by the crankcase at the bottom of the engine body E
A power transmission belt 5 made of an endless cog belt is connected between a driving pulley 3 that is integral with the engine body E, and a driven pulley 4 that is integral with a pair of valve drive camshafts 2 that are supported by the cylinder head at the upper part of the engine body E. Being hanged around.

A cooling water pump 7 is supported on the engine body E so as to be biased to one side (to the right in FIG. 1) from the cylinder axis L-L of the engine body E, which passes through the center of the crankshaft 1. A loose side 51 of the transmission belt 5 is suspended around the driven pulley 6 .

A tension pulley 8 is disposed approximately directly above the crankshaft 1 between the drive pulley 3 and the driven driven boot U 6 for driving the water pump 7. It is pressed against the side surface and applies a predetermined tension to the transmission belt 5.

The tension pulley 8 is rotatably supported via a ball bearing 11 on a pulley shaft 91 protruding from an intermediate portion of the swing lever 9. The base end of the swing lever 9 is pivotally supported on an end wall 13 of the engine body E by a support shaft 12 so as to be able to swing up and down, and a guide shaft 15 is attached to the pulley shaft portion 9I of the swing lever 9.
A long hole 10 is drilled to play with the swing lever 9, and an oil-supplied auto adjuster A for the transmission belt 5, which will be described in detail later, is connected to the tip of the swing lever 9. And this auto adjuster A
The tension pulley 8 is pressed against the transmission belt 5 by the control force of , and a constant tension is applied to the belt 5.

Further, the other end side of a tension spring 14 whose base end is tied to the end wall 13 of the engine body E is connected to the upper part of the intermediate position of the swing lever 9, and the tension force of this tension spring 14 is as follows. The swing lever 9 is biased so as to swing counterclockwise around the support shaft 12, and the tension pulley 8 is biased so as to come into pressure contact with the outer surface of the loose side 5I of the transmission belt 5.

A conventionally known hydraulic pump P is fixed to the end wall 13 of the engine body E for forcibly supplying lubricating oil or the like to each lubricated part of the engine body E, and this hydraulic pump P is directly connected to the crankshaft 1. It is driven by Then, the reservoir inside the engine body E is sucked in 1
It is discharged from the passage Pi (FIG. 4) to the suction and discharge passage Po.

The above-mentioned arrangement of the drive pulley 3, driven boob IJ 6, and tension pulley 8 allows the slack side 5. is largely recessed toward the tension side 5□ between the drive boob IJ 3 and the driven pulley 6, and a space S is formed there. In this space S, the oil supply type auto adjuster A is provided on the outer surface of the pump case 16.
An adjuster case 17 is integrally provided.

Incidentally, if the center of the tension pulley 8 is shifted toward the tension side 52 of the transmission band 9 with respect to the cylinder axis LL of the engine body E, the dead space D can be expanded.

Next, we will mainly discuss the structure of this oil-filled auto adjuster A.
Referring to FIG. 6, the adjuster case 17 of the auto adjuster A is integrally formed on the upper outer surface of the pump case 16. A hollow cylindrical housing 19 having an open upper end 18 is formed in the adjuster case 17 . A hollow cylindrical plunger case 21 having an open upper end 20 is fitted into the housing 19.
The upper outer periphery of the plunger case 21 and the housing 19
An O-ring 22 is interposed between the inner circumferential surfaces of.

A plunger 23 having a tapered upper part is slidably movable up and down inside the plunger case 21, and a plug 25 is fitted into the open upper end 24 of the plunger 23. A slipper member 27 is fitted into the recess 26 formed in the upper part of the plug 25 via an O-ring 29, and a slipper surface 28 is formed on the top surface of the slipper member 27. The lower end of an adjusting screw 30 that is adjustably screwed into the tip of the lever 9 is brought into contact.

The plunger 23 defines a high-pressure oil chamber 31 in the lower part of the plunger case 21, and a replenishment oil chamber 32 in the upper part thereof.

A valve port 33 is opened in the bottom wall 23d of the plunger 23, and the high pressure oil chamber 31 and the replenishment oil chamber 32 communicate with each other through the valve port 33. Inside the high pressure oil chamber 31, there is a check valve V for opening and closing the valve port 33, and a plunger 23.
The check valve V includes a spherical valve body 35 seated on the valve seat of the valve port 33, a valve cage 36 housing the valve body 35, and a tension spring 34 that springs the valve upward. It is composed of a valve spring 37 that urges the valve body 35 in the valve closing direction.

Below the O-ring 22, the side wall 21S1 of the plunger case 21 and the side wall 23 of the plunger 23
s includes a refueling hole 38 that communicates with each other at all times, and a cuff 3.
The oil supply hole 38 is communicated with an oil supply passage 40 bored in the adjuster case 17, and the oil hole 39 is communicated with the oil supply chamber 32.

The oil supply passage 40 communicates with a discharge port 41 of the hydraulic pump P. Therefore, when the hydraulic pump P connected to the crankshaft 1 is driven as the engine operates, pressurized oil from the pump always passes through the discharge port 41, the oil supply passage 40, the oil supply hole 38, and the oil hole 39. The refueling oil chamber 32 is forcibly refueled.

As clearly shown in FIG. 6, the oil supply passage 40 consists of a downstream passage 40d on the side of the oil supply chamber 32 and an upstream passage 40u on the side of the hydraulic pump P, and the open end of the downstream passage 40d is a plug. It is closed by a body 42. Downstream oil supply path 40d
A pressure regulating regulator R is built inside. This regulator R consists of a piston 46 that is slidably fitted into the downstream passage 4Ou to open and close the oil sump communication hole 44, and a spring 47 that biases the piston 46 toward the closing side.
゛When the oil pressure in the passage 40 rises above a predetermined value, the piston 46 is slid in the opening direction against the elastic force of the spring 47, and the oil sump communication hole 44 is communicated with the oil supply passage 40 to open the oil supply passage. The pressurized oil in 40 is returned to an oil reservoir 48 at the bottom of the engine body E.

An annular air bleed road 51 is formed between the outer periphery of the tapered upper part of the plunger 23 and the plunger case 21, and this air bleed road 51 is formed between the fitting surface of the open upper end 24 of the plunger 23 and the plug 25. It communicates with the replenishment oil chamber 32 via a leak passage 56 formed therein. Further, between the O-ring 22 and the supply hole 38, the plunger case 21
An oil drain hole 49 that opens to the air bleed road 51 is formed in the side wall 21s of the engine, and this oil drain hole 49 drains oil in the engine body E through an oil drain passage 50 formed in the plunger case 17. It communicates with the reservoir 48.

The oil in the replenishment oil chamber 32 flows together with the trapped air through the leak passage 56 to the air vent road 51, and further flows through the passage 5.
1, the oil is returned to the oil reservoir 48 in the engine body E through the oil drain hole 49 and the oil drain passage 50.

Furthermore, as shown in FIG. 5, an air vent road 52 is bored in the bottom of the housing 19 to communicate the lower part of the oil chamber 57 and the discharge port 41 of the oil pump P. This is for removing air sealed in the oil chamber 57 when the plunge middle case 21 is assembled.

The lower end of a boot 53 formed of rubber, synthetic resin, etc. is attached to a tightening ring 5 on the outer peripheral surface of the upper end of the plunge middle case 21.
4, and the upper end of the boot 53 is inverted and attached to the plug 25 by a tightening ring 55.
It is oil-tightly wrapped around the outer periphery of the The boot 53 expands and contracts to follow the elevation and descent of the plunger 23, thereby sealing the space between the plunger case 21 and the plug 25 in an oil-tight manner.

Next, the operation of the embodiment of the present invention will be explained.

When the engine is operated, the rotation of the crankshaft 1 is transmitted to a pair of valve drive camshafts 2 via a timed winding transmission T consisting of a drive pulley 3, a transmission belt 5, and a driven pulley 4.

The tension pulley 8 disposed on the slack side 51 of the transmission belt 5 is pressed against the transmission belt 5 by an auto adjuster A, and automatically operates in response to tension fluctuations on the slack side 5I of the transmission belt 5. A constant tension is applied to the transmission belt 5.

As shown in FIG. 1, the tension pulley 8 is disposed almost directly above the crankshaft l, and is connected to the transmission belt 5 between the drive wheel 3 on the crankshaft 1 and the driven wheel 6 for driving the water pump 7. Loose side 5. By pressing the transmission belt 5
can be wrapped around the driving wheels 3 and driven wheels 6 at a large angle.

Next, the function of the auto-adjuster A will be explained in more detail.

The same oil as the lubricating oil for the engine is filled in advance into the high-pressure oil chamber 31 and the replenishment oil chamber 32' in the plunge case 21. A portion of pressurized oil from a hydraulic pump P for lubricating the engine connected to the crankshaft 1 is supplied to a discharge port 41, an oil supply passage 40.
The replenishing oil chamber 32 is always forcibly supplied with oil through the oil supply hole 38 and the oil hole 39, and the replenishing oil chamber 32 is filled with oil. In addition, the oil in the replenishment oil chamber 32 passes through the leak passage 56 and the air bleed road 51 together with the trapped air sealed in the chamber 32, and then passes through the oil drain hole 49 and the oil drain passage 50 to the engine body. It is refluxed into the oil sump 48 at the bottom of E. In this case, the air trapped in the oil in the supply passage 32 passes through the leak hole 56 in the upper part and is easily discharged from the air vent road 51 to the oil drain hole 49.

And hydraulic pump P, auto adjuster A and oil sump 4
The oil flowing between 8 and 8 will not leak outside the engine body E.

When the oil pressure in the oil supply passage 40 exceeds a predetermined value, the piston 46 of the regie eletor R retreats against the elastic force of the spring 47, and the oil sump communication hole 44 communicates with the oil supply passage 40, causing the oil supply passage 4 to open.
The pressurized oil in 0 is returned to the oil reservoir 48.

In the auto adjuster A, the tension spring 34 in the high pressure oil chamber 31 pushes up the plunger 23 with its elastic force, and moves the swing lever 9 via the slipper member 27 and the adjustment screw 30 as shown in FIG. Swings counterclockwise. Thereby, the tension pulley 8 presses the loose side 5I of the transmission belt 5 inward, and applies a constant tension to the transmission belt 5.

The elastic force of the tension spring 14 also urges the swinging lever 9 to swing counterclockwise in FIG. 1, thereby assisting in applying tension to the transmission belt 5.

When the plunger 23 rises following the elongation of the transmission belt 5, the pressure in the high pressure oil chamber 31 is reduced, and the spherical valve body 35 of the check valve V is forced to close the valve port 3 due to the pressure difference with the replenishment oil chamber 32.
3 is opened, and the oil in the replenishment oil chamber 32 is supplied to the high pressure oil chamber 31 through the valve port 33.

During the operation of the timing winding transmission T, when a tensile force is applied to the loose side 51 of the transmission belt 5 due to torque fluctuations acting on the crankshaft 1, valve drive camshaft 2, etc., this tensile force pushes back the tension pulley 8. It also works to push down the plunger 23 via the swing lever 9. As a result, the oil pressure in the high-pressure oil chamber 31 increases and the spherical valve body 35 of the check valve V closes the valve port 33, thereby preventing oil from flowing back into the replenishment oil chamber 32, and eventually inside the high-pressure oil chamber 31. The hydraulic pressure suppresses the retreat of the tension pulley 8 by opposing the tensile force on the loose side 5I of the transmission belt 5.

When the tensile force is released from the loose side 51 of the transmission belt 5,
The plunger 23 rises again due to the elastic action of the tension spring 34, and the tension boob I78 presses the loose side 5I of the transmission belt 5 via the swing lever 9, applying a constant tension to the transmission belt 5 again, and the transmission is stopped. If the belt 5 has elongation, this can be compensated for. The high-pressure oil chamber 31, which is depressurized by the rise of the plunger 23, is replenished with the oil in the replenishment oil chamber 32 as described above.

In the above embodiment, the drive boolean 1) 3, the driven boot I74.6, the transmission belt 5, and the water pump 7 constitute the driving wheel, the driven wheel, the transmission belt, and the auxiliary machine in the present invention. It goes without saying that the present invention can be implemented not only in belt-type winding transmissions but also in chain-type and other winding transmissions.

C1 Effects of the Invention As is clear from the above embodiments, according to the present invention, on the loose side of the transmission band of the timed winding transmission device, the engine body is biased to one side from the cylinder axis passing through the center of the crankshaft. A driven wheel for driving an auxiliary device to be supported is suspended, and a tension pulley disposed approximately directly above the driving wheel is pressed against the outer surface of the loose side of the transmission belt between the driven wheel and the driving wheel, and On the outside of the tension pulley, an auto adjuster connected to the tension pulley is disposed in a space formed between the drive wheel and the auxiliary drive driven wheel to apply a constant tension to the transmission band. Therefore, the winding angle of the transmission band with respect to the driving wheel and the driven wheel is increased to reduce the load that partially acts on the transmission band, and the load applied to the teeth of the transmission band is reduced, thereby reducing the transmission of the transmission band. It is possible to increase the efficiency and extend the life of the transmission device, and to reduce the operating noise of the wrap transmission device.

Further, the auto-adjuster of the tension pulley is disposed in a space formed on the slack side of the transmission band, so that it hardly protrudes from the outer surface of the transmission band, making it possible to make the entire timed winding transmission device more compact.

[Brief explanation of the drawing]

The drawings show one embodiment of the device of the present invention, and FIG. 1 is a front view of a timed winding transmission device for an internal combustion engine equipped with the device of the present invention, and FIG. 2 is a view taken from the line shown in FIG. A side view, FIG. 3 is an enlarged sectional view taken along the line m-m in FIG. 1, and FIG.
The back view of the pump case along line V, Figure 5, is Figure 2 V.
- The enlarged cross-sectional view along line V, FIG. 6, is FIG.
FIG. 3 is a cross-sectional view of the adjuster case along a line. E... Engine body, A... Lubrication type auto adjuster,
L-L...Cylinder axis 1...Crankshaft, 2...Valve train camshaft, 3...
Drive wheel, 4... Driven wheel, 5... Transmission band, 51...
Loose side, 6... Driven wheel for driving auxiliary equipment, 7... Water pump, 8... Tension pulley Fig. 4 Fig. 2 Fig. 1-ff Fig. 5 Fig. 7-

Claims (1)

[Claims] A timing winding for an internal combustion engine in which an endless transmission band is suspended between a driving wheel integral with the crankshaft supported at the bottom of the engine body and a driven wheel integral with the valve drive camshaft supported at the upper part of the engine body. In the hanging transmission device, the cylinder axis L- of the engine body E passing through the center of the crankshaft is located on the loose side of the transmission band.
A driven wheel for driving auxiliary equipment supported by the engine body is suspended to one side from L, and between this driven wheel and the driving wheel, an abbreviation of the driving wheel is attached to the outer surface of the slack side of the transmission belt. A tension pulley disposed directly above is pressed against the tension pulley, and a space formed between the drive wheel and a driven wheel for driving auxiliary equipment on the outside of the tension pulley is provided in order to apply a constant tension to the transmission band. A tensioner device for a timed wrap transmission in an internal combustion engine, characterized in that an auto-adjuster connected to the tension pulley is provided.