JPS61252951A - Tentioner in entrained transmission of internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the functional efficiency and the sealing performance by sealing between the outer end of a plunger having an inner supply oil chamber while forming a high pressure oil chamber against the plunger case and the open end of the plunger case oil-tightly through a boot. CONSTITUTION:A plunger case 21 having an open upper end 20 is fitted in a cylinder hole 19 formed through an adjuster case 17. An O-ring 22 is placed between said plunger case 21 and the innercircumferential face of the cylinder hole 19. While a high pressure oil chamber 31 is formed by the bottom wall 23d of a plunger 23 arranged slidably in the plunger case 21 and the plunger case below said plunger 23 and a supply oil chamber 32 is formed in the plunger 23. A check valve V and a tension spring 34 are contained in said chamber 32, while a shrinkable boot 53 is applied oil-tightly between the upper ends of the plunger case 21 and the plunger 23.

Description

Detailed Description of the Invention A0 Objective of the Invention +1> Industrial Field of Application The present invention relates to an internal combustion engine in which a constant transmission band is attached to an endless transmission band suspended between a driving wheel and a driven wheel supported by an engine body. The present invention relates to a tensioner device for a wrap-around transmission that applies tension.

(2) Conventional technology In conventional internal combustion engines, an endless transmission band is suspended between the driving wheels and driven wheels, and an auto-adjuster is connected to the tensioner body that is pressed into contact with the transmission band. A device that applies a tension of 1 is known (Japanese Utility Model Publication No. 57-202039).

(3) Problems to be Solved by the Invention When the above-mentioned wrap-around transmission is of a belt type and the auto-adjuster is of a hydraulic type, oil leaking from the auto-adjuster may leak onto the transmission belt of the wrap-around transmission. If it adheres, the amount of slippage of the transmission belt will increase, leading to a decrease in transmission efficiency, and there will be problems in that it will stop deteriorating the transmission belt. In order to solve this problem, the hydraulic auto adjuster needs to be constructed in an oil-tight manner. However, if a sealing member is provided between the sliding parts of a hydraulic auto-adjuster, there is a problem that not only does the relative sliding resistance between them increase, but also the sealing member wears out and the sealing effect is not sufficient.

The present invention has been made in view of the above-mentioned circumstances, and it improves the operating efficiency of the auto-adjuster and its sealing performance by not providing a sealing member between the sliding parts of the hydraulic auto-adjuster. It is an object of the present invention to provide a tensioner device for a wrap transmission in an internal combustion engine.

B1 Structure of the Invention (Means for Solving 11 Problems) According to the present invention, in order to achieve the above object, an endless transmission belt is suspended between a driving pulley and a driven pulley supported by the engine body, and the transmission belt is In a tensioner device for a wrap transmission for an internal combustion engine, the tensioner is pressed against the slack side of the transmission belt to apply a predetermined tension to the transmission belt. The plunger is fitted into the plunger case, and a high-pressure oil chamber is formed below the plunger, and a replenishment oil chamber is formed inside the plunger, and the high-pressure oil chamber and the replenishment oil chamber are formed on the bottom wall of the plunger. The valve is connected to the high-pressure oil chamber through a bored valve port, and the valve port is closed when the pressure in the chamber is increased.
Further, a check valve that opens the valve opening when the pressure is reduced and a tension spring that biases the plunger in the extension direction and applies a predetermined tension to the slack side via the tensioner are accommodated, and the replenishment oil chamber has its oil supply hole opened. The oil supply source and the oil drain hole are communicated with the oil reservoir through closed oil passages, and the open end of the cylinder hole and the plunger case are oil-tightly sealed via a sealing member, and the open end of the cylinder hole is oil-tightly sealed. and the outer end of the plunger with an elastic boot.

(2) Function According to the above configuration, there is no seal member between the sliding parts of the hydraulic auto adjuster, and the auto adjuster and the outside are sealed oil-tight, so that no oil leaks into the belt two-wrap transmission device. will not stick to the surface.

(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 FIG. 1, a timing winding transmission T is provided on one end surface of an engine body E of the internal combustion engine for interlocking a crankshaft 1 and a pair of valve operating camshafts 2 of a valve operating mechanism. This timing winding transmission device T has an endless transmission belt 5 suspended between a driving pulley 3 fixed to a crankshaft l and driven pulleys 4 fixed to a pair of valve drive camshafts 2, respectively. configured.

Another driven pulley 6 is suspended in the middle of the transmission belt 5, and a cooling water pump 7 of the engine body E is driven by this driven pulley 6.

In FIGS. 1 to 3, between the driving pulley 3 and the other driven pulley 6, on the outside of the loose side 5 of the transmission belt 5,
A tension pulley 8 is provided, and the tension pulley 8 is rotatably supported via a ball bearing 11 on a pulley shaft 10 protruding from an intermediate portion of the swing lever 9. The base end of the rocking lever 9 is pivotally supported on the end wall 13 of the engine body E with a support shaft 12 so as to be able to swing up and down, and is provided with a long hole 9 in the middle thereof.
1 is loosely engaged with the guide shaft 15, and the swing lever 9
A hydraulic auto adjuster A of the transmission belt 5, which will be described in detail later, is connected to the tip of the transmission belt 5. The tension pulley 8 is moved by the pressing force of the auto adjuster A to the transmission belt 5.
The belt 5 is pressed against the belt 5 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 boob I78 is biased so as to come into pressure contact with the outer surface of the loose side 51 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 l. It is driven by Then, the reservoir in the engine body E is sucked up and discharged from the suction passage Pi' (FIG. 4) to the discharge passage Po.

On the outer surface of the pump case 16 of the hydraulic pump P, an adjuster case 17 for the oil supply type auto adjuster is integrally cast.

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 cylinder hole 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 cylinder hole 19.
A sealing member, that is, an O
A ring 22 is interposed, and the O-ring 22 seals the space between the cylinder hole 19 and the plunger case 21 oil-tight from the outside.

A plunger 23 is slidably moved up and down within the plunger case 21, and no sealing member is interposed between the sliding surfaces. 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 2 is attached to the top surface of the slipper member 27.
8 is formed. This slipper surface 28 is hardened to maintain wear resistance, and an adjustment screw 3 is screwed onto the surface 28 to be adjustably screwed into the tip of the swing lever 9.
The lower end of 0 is brought into contact.

The lower end edge of a telescopic boot 53 formed of rubber, synthetic resin, etc. is oil-tightly attached to the outer peripheral surface of the upper end of the plunger case 21 by a tightening member 54.
The upper edge of the plug 25 is inverted and is oil-tightly attached to the outer periphery of the plug 25 by another tightening member 55. This boot 53 expands and contracts to follow the rise and fall of the plunger 23,
To oil-tightly seal a communication gap with the outside between a plunger case 21 and a plunger 23.

A high pressure oil chamber 31 is formed below the plunger 23 by its bottom wall 23d and the plunger case 21,
Further, a replenishment oil chamber 32 is formed within the plunger 23.

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.
A tension spring 34 that springs the valve upward is housed in the check valve (2). It is composed of a valve spring 37 that urges the valve body 35 in the valve closing direction.

Below the O-ring 22, an oil supply hole 38 is provided penetrating through the side wall 21g of the plunger case 21, and this oil supply hole 38 is supplied with oil through an oil hole 39 formed in the side wall 235 of the plunger 23. It is constantly communicated with the oil chamber 32. Further, the oil supply hole 38 communicates with an oil supply passage 40 formed in the adjuster case 17.

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 is operating, the pressurized oil always flows through the discharge port 41, oil supply passage 40, oil supply hole 38, and oil hole 39. The replenishment 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. The regulator R includes a piston 46 that is slidably fitted into the downstream passage 40d to open and close the oil reservoir communication hole 44, and a spring 47 that biases the piston 46 toward the closing side. When the oil pressure of the spring 47 increases to a predetermined value or more, the spring 47
The piston 46 is slid in the opening direction against the elastic force of the piston 46, the oil sump communication hole 44 is communicated with the oil supply passage 40, and the pressurized oil in the oil supply passage 40 is returned to the oil sump 48 at the bottom of the engine body E. It looks like this.

An oil drain hole 49 is formed in the side wall 213 on the plunger case 21 side between the O-ring 22 and the oil supply hole 38 . This oil drain hole 49 connects a leak oil chamber 51 formed between the plunger case 21 and the plunger 23 to the cylinder hole 1.
It communicates with an oil drain passage 50 formed at 9, and this oil drain passage 50 communicates with an oil reservoir 48 (FIG. 6) in the engine body E.

A leak passage 56 is formed between the open upper end 24 of the plunger 23 and the fitting surface of the plug 25.
The replenishment oil chamber 32 is communicated with the leak oil chamber 51 through the replenishment oil chamber 32, and the oil in the replenishment oil chamber 32 flows together with trapped air through the leak passage 56 to the leak oil chamber 51, and further from the leak oil chamber 51 to the leak oil chamber 51. Oil drain hole 49 and oil drain passage 50
The oil passes through the engine body E and is returned to the oil reservoir 48.

Further, as shown in FIG. 5, an air bleed road 52 is bored at the bottom of the cylinder hole 19 to communicate the lower part of the high pressure oil chamber 31 and the discharge port 41 of the oil pump P. When assembling the plunger case 21 into the hole 19, the empty space 5 between the lower part of the cylinder hole 19 and the plunger 21 is
This is to remove the air sealed in the chamber 7.

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.

Loose side of the transmission belt 55. A tension pulley 8 disposed on 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, thereby maintaining a constant tension on the transmission belt 5. Grant.

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

The same oil as the lubricating oil of the engine is injected into the high pressure oil chamber 31 in the plunger case 21 in advance. Also, a part of the pressurized oil from the hydraulic pump P for lubricating the engine connected to the crankshaft 1 is constantly forced into the replenishment oil chamber 32 through the discharge port 41, the oil supply passage 40, the oil supply hole 38, and the oil hole 39. The replenishment oil chamber 32 is filled with oil. Also, the replenishment oil room 32
The oil inside passes through the leak passage 56 together with the trapped air sealed in the chamber 32 and reaches the sealed leak oil chamber 51.
From there, the engine body E passes through the oil drain hole 49 and the oil drain passage 50.
The oil is refluxed into the oil sump 48 at the bottom. Therefore, the oil flowing between the hydraulic pump P1 auto-adjuster A and the oil reservoir 48 does not leak to the outside of the engine body E, and lubricating oil is constantly supplied to the replenishment oil chamber 32 of the auto-adjuster A during engine operation.

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. is short-circuited to the oil sump 48 to keep the oil pressure in the passage 40 constant.

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. As a result, the tension pulley 8 is applied to the slack side 5. of the transmission belt 5. is pressed inward to apply 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 recheck valve V closes the valve opening due to the pressure difference with the replenishment oil chamber 32. 33 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 operation of the timing winding transmission T, the slack side 5 of the transmission belt 5 is caused by torque fluctuations acting on the crankshaft 1, valve drive camshaft 2, etc. When a tensile force is applied to , this tensile force acts to push back the tensing lever 9
It acts to push down the plunger 23 via the . 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 of 5. on the loose side of the transmission belt 5. By resisting the tensile force of

Loose side of transmission belt 55. When the tensile force is released from
The plunger 23 rises again due to the elastic action of the tension spring 34, and the tension pulley 8 presses the loose side 51 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.

During the above operation, the pressurized oil from the hydraulic pump P is constantly supplied into the replenishment oil chamber 32 as described above, so that any leakage of oil in the replenishment oil chamber 32 can be immediately replenished, and the replenishment oil By constantly replenishing oil into the chamber 32,
The trapped air can also be easily discharged into the chamber 32.

Furthermore, even though pressure oil is constantly supplied from the hydraulic pump P into the replenishment oil chamber 32, the pressurized oil leaks to the outside from the adjuster case 17 due to the cooperation of the O-ring 22 and the elastic boot 53. Moreover, since a sealing member for oil-tightly sealing the adjuster 17 and the outside is not provided between the sliding surfaces of the plunger case 21 and the plunger 23, the sliding resistance of the plunger 23 is not increased by them. , and they will not wear out.

In the above embodiment, the tension pulley 8 and the O-ring 22 constitute the tensioner and seal member of the present invention.

C8 Effects of the Invention As is clear from the above embodiments, according to the present invention, a plunger case is fitted into the cylinder hole of the adjuster case provided in the engine body, the plunger is slid onto the plunger case, and the plunger is moved downward. A high-pressure oil chamber is formed in the chamber, and a replenishment oil chamber is formed inside the high-pressure oil chamber, and the high-pressure oil chamber and the replenishment oil chamber are communicated with each other through a valve hole bored in the bottom wall of the plunger, and the high-pressure oil chamber is connected to the replenishment oil chamber. closes the valve port when the pressure in the acid chamber increases and opens the valve port when the pressure decreases (a check valve and a tension spring that biases the plunger in the extension direction and applies a predetermined tension to the slack side via the tensioner). accommodates,
The replenishment oil chamber communicates its oil supply hole with the oil supply source and its oil drain hole with the oil reservoir through closed oil passages, and maintains an oil-tight connection between the open end of the cylinder hole and the plunger case via a sealing member. At the same time, since the open end of the cylinder hole and the outer end of the plunger were oil-tightly sealed with an elastic boot, pressurized oil was constantly supplied into the replenishment oil chamber and any leakage of oil in the replenishment oil chamber was prevented. It is possible to replenish the oil immediately, and it is also easy to discharge trapped air into the replenishment oil chamber. In addition, even though the plunger case is constantly replenished with pressurized oil, leakage of the pressurized oil to the outside is reliably prevented, and there is no risk of the leaked oil adhering to the transmission belt. transmission efficiency can be increased.

In addition, since there is no seal member between the sliding surfaces of the plunger case and plunger that prevents pressurized oil from leaking out of the adjuster case, not only will they not increase the sliding resistance of the plunger, , their reliable sealing function can be maintained over a long period of time, and furthermore, the sealing member and the elastic boot do not wear out, increasing their durability.

[Brief explanation of the drawing]

Figures 1 to 6 show an embodiment of the device of the present invention.
The figure is a front view of a timing winding transmission device for an internal combustion engine equipped with the device of the present invention, Figure 2 is a side view taken along the line ■ in Figure 1, and Figure 3 is taken along line 1-1 in Figure 1. The enlarged sectional view, Figure 4, is the same as Figure 2r.
5 is an enlarged sectional view taken along line V-V in FIG. 2, and FIG. 6 is a back view of the pump case taken along line V-IV.
- Cross-sectional view of the adjuster case along the Vl line E...Engine body, ■...Check valve 3...Drive pulley, 4...Driven pulley, 5...Transmission belt, 8...
...Tension pulley as a tensioner, 17...
Adjuster case, 19... cylinder hole, 21...
Plunger case, 22... O-ring as a sealing member, 23... Plunger, 31... High pressure oil chamber, 3
2... Replenishment oil chamber, 33... Valve port, 34... Tension spring, 38... Oil supply hole, 48... Oil sump, 49... Oil drain hole, 53... Boot special Applicant Honda Motor Co., Ltd. Koji Fig. 2-ff Fig. 5 Fig. 6

Claims (1)

[Claims] An internal combustion engine in which an endless transmission belt is suspended between a driving pulley and a driven pulley supported by an engine body, and a tensioner is pressed against the slack side of the transmission belt to apply a predetermined tension to the transmission belt. In a tensioner device for a wrap-around transmission, a plunger case is fitted into a cylinder hole of an adjuster case provided in the engine body, a plunger is slid onto the plunger case, and a high-pressure oil chamber is provided below the plunger, and a high-pressure oil chamber is provided inside the plunger case. Replenishment oil chambers are respectively formed, and the high pressure oil chamber and the replenishment oil chamber are communicated via a valve port bored in the bottom wall of the plunger, and the high pressure oil chamber is provided with a valve port when the pressure of the chamber is increased. and a check valve that opens the valve port when the pressure is reduced, and a tension spring that biases the plunger in the extension direction to apply a predetermined tension to the slack side via the tensioner, and the replenishment oil chamber accommodates The oil supply hole is connected to the oil supply source and the oil drain hole is connected to the oil reservoir through closed oil passages, respectively.
An internal combustion engine characterized in that the space between the open end of the cylinder hole and the plunger case is oil-tightly sealed via a sealing member, and the space between the open end of the cylinder hole and the outer end of the plunger is oil-tightly sealed with an elastic boot. A tensioner device for a wrapped transmission in an engine.