JPH11132299A - Idler integrated hydraulic automatic tensioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably correct tensile force by controlling a working fluid between a damper chamber and a reservoir, instantly allowing idler propelling motion by two kinds of energizing means at tensile force reducing time of a belt-like motive power transmitting member, and gradually allowing retreat motion at tensile force increasing time. SOLUTION: When tensional force of a timing belt becomes a preset value or less, a spring 60 push-moves the belt through an idler, and a damper chamber R1 is put under negative pressure by projecting operation of a piston 40 by a spring 43 having energizing force weaker than the spring 60, and a ball valve 41 is opened, and a working fluid flows in the damper chamber R1 from a reservoir chamber. When the tensional force of the belt exceeds the preset value, the belt push-moves the idler, and pressure in the damper chamber R1 increases by intrusion of the piston 40 to close the ball valve 41, and the working fluid in the damper chamber R1 flows in the reservoir through a fitting clearance between the piston 40 and a cylinder inside hole 31a and a communicating hole of the piston 40. Therefore, a movement of the idler becomes quick for looseness of the belt, and becomes slow for tension, precisely adjusting the tensional force of the belt can.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic auto-tensioner which is used to constantly apply a proper tension to a belt-like power transmission member such as a chain or a belt, and more particularly to a hydraulic auto-tensioner having a tensioner in an idler. The present invention relates to an idler-integrated hydraulic auto tensioner.

[0002]

2. Description of the Related Art Conventionally, as one type of hydraulic auto-tensioner, an auto-tensioner that always keeps the tension of a belt-like power transmission member such as a chain or a belt properly properly through an idler that is in rolling contact with the power transmission member is provided in the idler. Housed in
An idler-integrated auto-tensioner in which the idler is caused to linearly propell or retreat with respect to a power transmission member by the auto-tensioner has been considered, and is disclosed in, for example, Japanese Utility Model Laid-Open No. 6-1891.

[0003]

However, the idler-integrated auto tensioner disclosed in the above publication has a structure in which the idler is loosely fitted to the outside of the body fixed to the fixing member, and the idler is axially inserted into the cylinder bore of the body. Is fitted to the tip of the piston slidably mounted to
Smooth linear movement of the idler is not guaranteed, and proper tension correction may not be possible. In addition, since the piston is pushed by a spring coaxially arranged inside the piston to push the idler, it is conceivable that an appropriate tension correction is not performed.

[0004] In view of the above, it is a technical object of the present invention to provide an idler-integrated auto tensioner capable of reliably performing appropriate tension correction in order to solve the above problems.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an invention according to claim 1 includes an outer ring member that is in rolling contact with a belt-shaped power transmission member, and an inner ring member that is rotatably supported relative to the outer ring member. A piston extending radially inward of the idler and urged by the first urging means toward the inner ring member of the idler and having a closed distal end; and a piston slidably fitted in the axial direction. A body inserted into the closing portion to form a damper chamber in the closing portion, the body being housed in the idler and being fixed to a fixing member such that the piston can advance and retreat with respect to the belt-like power transmission member; and a body and the idler. A second urging means disposed between the piston and the body for urging the idler toward the belt-shaped power transmission member and having a larger urging force than the first urging means; and a damper chamber provided between the piston and the body. In the reservoir room When the tension of the belt-shaped power transmission member is reduced, the urging means immediately allows the propulsion movement of the idler when the tension of the belt-shaped power transmission member decreases, and when the tension of the belt-shaped power transmission member increases, the idler resists the biasing means. And an attenuating means for attenuating the movement of the idler by gradually allowing the backward movement of the idler.

According to the first aspect, the piston is urged toward the inner ring member by the first urging member, and the piston operates following the operation of the idler. As a result, even if the direction in which the idler advances and retreats is not parallel to the operation direction of the piston, that is, if the idler does not advance and retreat in parallel with the axis of the cylinder bore, the operation of the piston in the cylinder bore does not occur. Since the piston is regulated by the biasing means, the sliding direction of the piston is not affected, and the piston can slide smoothly.

According to a second aspect of the present invention, in the first aspect, the idler has a sliding surface that has the same cross-sectional shape within an operating range and that comes into contact with and slides on the body. .

According to the second aspect, the sliding between the idler and the body is regulated by the sliding surface between the idler and the body, so that the sliding direction of the piston and the moving direction of the idler do not largely deviate. Further, depending on the shape of the sliding surface, it is possible to regulate the moving direction of the idler. Therefore, the idler and the piston operate smoothly.

According to a third aspect of the present invention, in the second aspect, the sectional shape of the sliding surface of the idler with the body is substantially semicircular.

According to the third aspect, the movement direction of the idler can be restricted, and the processing of the sliding surface is simple, which is advantageous in manufacturing.

The invention according to claim 4 is the invention according to claims 1 to 3.
In the above, the moving distance of the idler in the retreating direction is regulated by a notch formed in the idler and a pin protruding from the fixing member and moving in and out of the notch.

According to the fourth aspect, since the pin that moves in and out of the notch protrudes from the fixing member, it is possible to suppress play that occurs in a direction different from the direction in which the idler moves.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1 to 5 show an idler-integrated auto tensioner according to the present embodiment, and FIG.
3 is a cross-sectional view taken along line BB of FIG. 1, FIG. 4 is a cross-sectional view taken along line CC of FIG. 2, and FIG. The auto tensioner in the present embodiment is
The idler 10 is used to constantly apply appropriate tension to the timing belt V that transmits the power of the crankshaft (not shown) of the engine to the camshaft (not shown). And this idler 1
Engine block 2 which is housed in
1 has a body 31 attached by pins 25 and bolts 26.

The idler 10 includes an outer race member 11 that is in rolling contact with the timing belt V, and an inner race member 13 that rotatably supports the outer race member 11 via a number of balls 12.
The housing 14 is fitted and fixed to the inner periphery of the inner ring member by press-fitting, respectively, and the housing portion 14a for housing the spring 60 as second urging means for urging the idler 10 toward the timing belt V. Have.

A cylinder 31 has a cylinder bore 31a in which a piston 40 is slidably inserted in the axial direction thereof through a seal ring 32 to form a damper chamber R1 in which a closing portion is filled with hydraulic oil. A part 33 is formed, and the body 31 is moved to the engine block 21 such that the piston 40 can advance and retreat with respect to the timing belt V.
Mounted on Further, the cylinder inner hole 31a is provided substantially parallel to the accommodating portion 14a so as to be deviated by a predetermined amount in the axial direction of the idler 10 (vertical direction in FIG. 1). A spring 43 serving as a biasing means is disposed on the same axis as the piston 40 in the axial direction of the idler 10.

The piston 40 is a piston that extends radially inward of the idler 10 and is urged outward by the spring 43 to have its tip closed. Further, it has a reservoir chamber R2 in which the hydraulic oil and the air A are sealed.

At the distal end of the piston 40, a ball valve 41 and a retainer 42 are assembled corresponding to the communication valve holes 40a provided in the distal end closing portion, and a check valve for preventing flow to the reservoir chamber R2 is formed. A radial communication hole 40b for guiding hydraulic oil flowing through a fitting gap (throttle) between the piston 40 and the cylinder inner hole 31a to the damper chamber R1 is provided, and the ball valve 41, the retainer 42, and the communication hole are provided. The damping means for suppressing the flow of the hydraulic oil between the damper chamber R1 and the reservoir chamber R2 is constituted by 40b. This damping means allows the idler 10 to be immediately propelled by the spring 60 when the tension of the timing belt V decreases, and gradually reduces the retraction movement of the idler against the spring 60 when the tension of the timing belt V increases. The movement of the idler 10 is attenuated by allowing it.

In the reservoir chamber R2, a predetermined air A is stored together with hydraulic oil, and the air A is mounted on the engine block 21 so as to be located on the plug 18 side.

In the present embodiment configured as described above, when the timing belt V becomes slack during use after assembly and the tension of the timing belt V falls below a set value, the idler 10 is actuated by the spring 60. It is pushed and propelled toward the timing belt V to push the timing belt V (two-dot chain line in FIG. 5). At this time,
The damper chamber R1 becomes negative pressure due to the projecting operation of the piston 40 accompanying the movement of the idler 10, whereby the ball valve 41 opens the communication valve hole 40a, so that hydraulic oil flows from the reservoir chamber R2 into the damper chamber R1.

On the other hand, when tension is generated in the timing belt V and the tension of the timing belt V exceeds a set value, the idler 10 and the like are pushed by the timing belt V against the spring 60 (solid line in FIG. 5). . At this time, the damper chamber R1 is pressurized by the advancing operation of the piston 40 accompanying the movement of the idler 10, the ball valve 41 closes the communication valve hole 40a, and the hydraulic oil in the damper chamber R1 is filled with the piston 40 and the cylinder bore 31a. Between the fitting gap between the reservoir chamber R and the communication hole 40b provided in the piston 40.
Flow into 2.

Therefore, in the present embodiment, the movement of the idler 10 and the like becomes quick when the timing belt V is slack, and the movement of the idler 10 and the like is slow when the timing belt V is tight. Thus, the movement of the idler 10 and the like is attenuated, and the tension of the timing belt V is accurately adjusted.

In the present embodiment, the cylinder section 33 has a sliding surface 31c which has the same arbitrary cross-sectional shape within the operating range and which comes into contact with and slides with the housing 14. In the present embodiment, the sectional shape of the sliding surface 31c of the body is a semicircular shape, and the sliding surface can be formed by simple cutting. In addition, a resin bush 50 is provided between the housing 14 and the sliding surface 31c to suppress abrasion for reducing sliding resistance.

The travel distance of the idler 10 in the advancing and retreating direction is determined by notches 14 formed at three places of the housing 14.
b, and the pin 25 and the bolt 26 protruding from the engine block 21 corresponding to the notch 14b. The idler 10 advances and retreats along the notch, so that the axial center in the reciprocating direction can be prevented from shifting. Will be possible. Further, the play of the idler 10 in the axial direction is restricted by the head 26a of the bolt 26, and the idler 10 does not operate deviating from the forward / backward direction.
The body 31 is fixed to the engine block 21 by 6b.

[0024]

According to the first aspect, the piston is urged toward the inner ring member by the first urging member. As a result, even if the operating direction of the idler is not parallel to the sliding direction of the piston, the operation of the piston in the cylinder bore is restricted by the first biasing means. Has no effect and the piston can slide smoothly.

According to the second aspect, the sliding between the idler and the body is defined by the sliding surface between the idler and the body, so that the sliding direction of the piston and the moving direction of the idler are not largely deviated. Further, depending on the shape of the sliding surface, it is possible to regulate the moving direction of the idler. Therefore, the idler and the piston operate smoothly.

According to the third aspect, the movement direction of the idler can be restricted, and the working of the sliding surface is simple, which is advantageous in manufacturing.

According to the fourth aspect of the present invention, since the pins that move in and out of the cutouts protrude from the fixing member, it is possible to suppress play that occurs in a direction different from the direction in which the idler moves.

[Brief description of the drawings]

FIG. 1 is a top view of an idler-integrated auto tensioner according to the present embodiment.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along the line CC of FIG. 2;

FIG. 5 is a diagram showing the operation of the auto tensioner of the present embodiment.

[Explanation of symbols]

10 ... Idler 11 ...
Outer ring member 12 ・ ・ ・ Ball 13 ・ ・ ・
Inner ring member 14 ... housing 14a
・ Notch 14b ・ ・ ・ Accommodation part 21 ・ ・ ・ Engine block (fixing member) 25 ・ ・ ・
Pin 26 ... bolt 31 ...
Body 31a ・ ・ ・ Cylinder bore 31c
・ Sliding surface 33 ・ ・ ・ Cylinder part 40 ・ ・ ・
Piston 40a: communication valve hole 40b
・ Communication hole 41 ・ ・ ・ Ball valve 42 ・ ・ ・
Retainer 50 ... Sleeve 43 ... Spring (first biasing means) 60 ... Spring (second biasing means) R1 ... Damper chamber R2 ...
Reservoir chamber V: Timing belt (belt-shaped power transmission member)

Claims (4)

[Claims] 1. An idler comprising: an outer ring member that is in rolling contact with a belt-shaped power transmission member; and an inner ring member that is rotatably supported with respect to the outer ring member; and an idler that extends radially inward of the idler. A piston whose end is closed while being urged toward the inner ring member side of the idler by the urging means, and a cylinder inner hole in which the piston is slidably fitted in the axial direction to form a damper chamber in the closed portion. A body fixed to a fixing member so that the piston can advance and retreat with respect to the belt-like power transmission member; and a body disposed between the body and an idler, with the idler facing the belt-like power transmission member. A second urging means that is energized and has a larger urging force than the first urging means; and a second oil urging means provided between the piston and the body for controlling the flow of hydraulic oil between the damper chamber and the reservoir chamber. Control the strip When the tension of the force transmitting member decreases, the urging means allows the idler to promptly move forward. And an attenuating means for attenuating the movement of the idler by allowing the idler to move. 2. The idler-integrated hydraulic auto-tensioner according to claim 1, wherein the idler has a sliding surface that has the same arbitrary cross-sectional shape within an operation range and that contacts and slides on the body. 3. The idler-integrated hydraulic auto-tensioner according to claim 2, wherein a cross-sectional shape of a slide surface of the idler with the body is substantially semicircular. 4. The moving distance of the idler in the reciprocating direction is regulated by a notch formed in the idler and a pin protruding from the fixing member and moving in and out of the notch. The idler-integrated hydraulic auto-tensioner according to claim 3.