JP2006009909A - Register ring incorporated structure of chain tensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a register ring incorporated structure of a chain tensioner capable of perfectly preventing the wrong incorporation of a register ring only by properly setting shape and dimension of the register ring, relating to the chain tensioner of the type of incorporated register ring where switching of operation states such as initial setting, return action regulation, and decomposition regulation of the chain tensioner is smooth, allowing operation of widening of diameter in maintenance work from outside. <P>SOLUTION: A register ring 6 is provided to engage with an engaging groove 11 of a plunger 2 which is inserted in a housing 1 for free sliding for initial set state, return action regulation, decomposition regulation or the like. Relating to a chain tensioner A, to prevent the register ring 6 from misincorporated reversely in axial direction, length L1 of a tip end 6c in an initial set state is formed longer than length L<SB>2</SB>from a ring housing groove end 9b to a depth wall 7a of a notch 7, allowing a base part 6b to be incorporated only in a correct direction in the notch 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a registering structure for a chain tensioner in which a register ring is incorporated in a chain tensioner that drives a camshaft of a vehicle engine.

  In a chain transmission device including a chain tensioner that transmits the rotation of a vehicle engine to a camshaft, the chain tensioner is generally disposed on the slack side of the chain so as to keep the chain tension constant. The chain tensioner has a spring and plunger built into the housing, and gives the plunger outward protrusion by the elastic force of the spring. The plunger is pressed into a tensioned state, and the pushing force from the chain is reduced. When acting on the plunger, it is buffered by the hydraulic pressure in the hydraulic damper chamber provided in the inner part of the plunger, and is provided so as to keep the tension constant even if the chain tension varies.

  Such general chain tensioners have inconveniences such as reduced damping characteristics and abnormal noise that occur when the engine is restarted after the engine is stopped, as well as reduced axial dimensions, machining accuracy, operating conditions, and handling characteristics. There are various problems such as improvement, and “Chain Tensioner” in Patent Document 1 is known as an example of a proposal for dealing with such problems. This chain tensioner has a plunger in the housing and a return spring inserted in the hollow portion of the plunger so as to give outward protrusion, and can be engaged with a plurality of grooves formed on the outer periphery of the plunger. The register ring, the check valve for preventing the back flow of the working fluid supplied into the housing, and the first stopper for restricting the retreat of the plunger are provided.

  The chain tensioner configured as described above has a ring part and an operation part for expanding the ring part in the register ring, and the operation part is provided in the housing part so that the operation part can be operated from the outside of the housing. It is provided so that it can be operated from the notch. The operation portion is formed by intersecting the end portions of the register ring, and is provided in non-contact with the cylinder. For this reason, various advantages such as smooth and easy switching of the operating state of the chain tensioner (initial setting, return movement restriction, disassembly restriction, etc.) and improved handling are obtained.

However, since the operation portion of the register ring is configured to be in non-contact with the housing, the register ring can be assembled even when the register ring is installed in the reverse direction. If the assembling direction is reversed, the intersecting portion of the register ring interferes with the engaging surface of the engaging groove on the outer periphery of the plunger when the engine is restarted, and this causes the wear of the register ring and the plunger to increase. This is because it is necessary to form the base part of the operation part of the register ring in a cross shape, and the other base part is bent and extended by the wire diameter of the register ring with respect to one base part. This is because the bent portion engages with the engaging surface of the engaging groove and damages and wears the crossing portion of the register ring and the engaging groove. For this reason, it has been desired to prevent such misassembly of registering, but no proposal has been made to solve this problem.
JP 2001-355691 A

  In consideration of the above-mentioned problems, the present invention provides a register ring that enables smooth switching of operation states such as initial setting of the chain tensioner, return movement restriction, disassembly restriction, etc., and allows the diameter expansion during maintenance work to be operated from the outside. It is an object of the present invention to provide a chain tensioner register ring built-in structure that can completely prevent register ring misassembly in a built-in type chain tensioner simply by appropriately setting the shape and dimensions of the register ring.

According to the present invention, taking the above-mentioned problem as a means, a cylinder chamber is formed in the housing, and a plunger is slidable in the cylinder chamber, and a spring is inserted into a hollow portion in the plunger and presses the plunger outward. An oil supply passage is communicated with a pressure chamber formed on the back side of the plunger at the closed end of the housing, and a check valve for preventing the backflow of the hydraulic oil fed thereby is provided on the passage of the oil supply passage, on the outer periphery of the plunger and on the shaft. A plurality of engaging grooves and ring receiving grooves are formed on the inner periphery of the opening of the cylinder chamber at intervals in the direction, and elastic in the radial direction of the register ring having a ring portion and an operating portion that can be engaged with the engaging grooves. The deformable ring part is housed in the ring housing groove, and the engagement groove engages with the taper surface that expands the ring part when the plunger protrudes and the ring part when the plunger retracts In the chain tensioner, which is formed by an engagement surface that prevents the plunger from moving backward, and the pushing force applied to the plunger by the hydraulic oil from the oil supply passage is buffered, the diameter of the ring portion of the register ring can be expanded. The base of the operating part to be operated is accommodated in the notch of the housing and the tip of the operating part is formed so as to protrude from the housing, and the length L ₁ of the operating part is the length from the ring receiving groove end to the notch back wall it is configured and then was of registering embedded structure of the chain tensioner is set longer than L _2.

  According to the above-described structure of the chain tensioner register ring built-in structure of the present invention, when the plunger and the spring are assembled into the housing, it is possible to completely prevent the register ring from being erroneously assembled. When assembling a plunger or spring into the housing, use a notch from the opening end of the housing in advance to insert a register ring into the ring receiving groove near the opening end, and then operate the register ring operation part manually or with a tool. Insert the spring and plunger into the housing with the ring portion expanded in diameter, insert the plunger deepest to the deepest position, and advance to the position adjacent to the engagement groove closest to the other end among the multiple engagement grooves of the plunger. The initial set state is assumed.

When the plunger is assembled in such an initial set state, if the register ring is assembled in the direction opposite to the normal assembling direction, the length L ₁ of the operation portion is reduced to the depth of the notch. since the is formed longer than the length L _2, forcibly ring portion by utilizing the notch is even can be inserted into the ring accommodating groove, the tip of the operating portion abuts on the notch inner wall, an operation portion Cannot be accommodated in the notch. Therefore, it is possible to completely prevent the wrong installation in the reverse direction.

  The basic action of the chain tensioner is the same as before, and the spring is given outward protrusion by the spring, and when a pushing force is applied to the plunger, it is buffered by the hydraulic damper chamber and the chain tension is always constant. It has the function to hold. Also, by providing a register ring, the initial setting of chain tensioner, return movement regulation, disassembly regulation, etc. can be switched smoothly and easily, improving handling, preventing register ring deformation, and reducing the number of parts. The chain tensioner described in Patent Publication 1 has all the functions such as reduction, prevention of the plunger from falling off the housing, easy disassembly of the plunger, and smooth movement of the plunger. It is the same as the function it has.

  In the chain tensioner of the present invention, the tip of the operation portion of the register ring protrudes from the housing, and the length of the operation portion is longer than the length from the ring receiving groove end to the notch back wall. In addition, when the plunger and the spring are assembled, it is possible to completely prevent the register ring from being erroneously assembled, and since the register ring can be operated from the outside, the operability can be ensured.

Hereinafter, a chain tensioner of an embodiment will be described with reference to the drawings. FIG. 1 is a main sectional view of a chain tensioner. This cross-sectional view is a cross-sectional view seen from the direction of arrow I in FIG. The chain tensioner A shown in the figure is basically the same as the chain tensioner of Patent Document 1, but the detailed structure for providing the register ring is different. In the following, the same basic structure is simply described in detail. The structure will be described in detail. As shown in the figure, the chain tensioner A includes a housing 1, a plunger 2 slidably inserted into a cylinder chamber 1a on the inner periphery of the housing, a return spring 3 inserted into the hollow portion 2a inside the plunger 2, and a housing 1 check valve 4 provided on the closed end of the pressure chamber 8 to be described later, the oil supply passage 5 for supplying hydraulic oil to the hydraulic damper chamber 8 _D, the notch is formed on the opening side end of the housing 1 7, ring-accepting A register ring 6 inserted in the groove 9 is provided as a main constituent member.

The housing 1, one end 1 _E as a closed end, the other end 1 _CE is formed by being open bottomed cylindrical body, mounting portion 1 _X provided diagonally across the cylinder chamber 1a in plan view in FIG. 2 It is formed so as to be attached to an engine block (not shown) via (only one side is shown, the other is provided at the upper left position in the figure). In addition, hydraulic oil supplied from a tank (not shown) that is left below the housing 1 is supplied to the pressure chamber via an oil supply passage 5 at the end of the housing, a communication chamber 5a communicating with the oil supply passage 5, and a flow path 5b formed in the valve seat 4b. 8 to be sent. The check valve 4 is provided in order to prevent the hydraulic oil from the pressure chamber 8 from flowing back by closing the valve seat provided at the pressure chamber 8 side end of the flow path 5b of the valve seat 4b with the check ball 4a. Yes. 4c is a retainer for restricting the movement of the check ball, and 4d is a notch.

Note that one end of the return spring 3 inserted into the hollow portion 2a of the plunger 2 is abutted and supported by the valve seat 4b, and the other end abuts the inner end of the hollow portion 2a and protrudes outward with respect to the plunger 2. Has been given sex. Further, as shown in the drawing, since the end of the hollow portion 2a is open, the pressure chamber 8 formed between the end of the plunger 2 inserted into the cylinder chamber 1a and the valve seat 4b communicates with the hollow portion 2a. As a whole, a hydraulic damper chamber _8D is formed. An annular safety groove 10 is formed on the outer peripheral portion of the plunger 2 slightly behind the center in the length direction. When the plunger 2 protrudes outward, the safety groove 10 has an end wall 9b (second stopper) of the ring receiving groove 9 in which the register ring 6 that engages with the rear end of the groove is provided at the opening end of the cylinder chamber 1a. ) And thereby provided to restrict the jumping-out of the plunger 2 (disassembly restriction). The register ring 6 will be described later.

  Furthermore, a plurality of annular engagement grooves 11 (six in the example shown, 11a to 11f) provided at equal intervals in the axial direction are provided on the outer periphery near the other end from the center of the plunger 2, and the other end is the most. An annular set wall 12a is formed on the end surface of the projecting portion 12 further toward the outer end of the closer engaging groove 11f (for initial setting). The annular engagement groove 11 has a serrated uneven shape in a cross-sectional view, and each groove shape has a tapered wall surface on both sides in the axial direction from the position of the minimum diameter, and a wall surface near one end thereof has a gentle slope shape. In the (taper surface), the wall surface near the other end has a larger inclination angle (engagement surface or lock surface) than the one end side wall surface. The tapered surface and the engaging surface are formed as a smoothly continuous curved surface. A cylindrical surface is left at a position adjacent to each annular engagement groove 11.

  The annular set wall 12a is engaged with the end wall 9b as the second stopper of the ring receiving groove 9 by engaging the register ring 6 engaged therewith, so that the chain tensioner A is in an initial set state (shown in FIG. 1). State). Further, the rear side wall 9a of the ring receiving groove 9 is formed as a tapered surface having a small inclination angle and as a first stopper, whereas the end wall 9b has a large angle close to a right angle. The ring receiving groove 9 is formed to have a predetermined length as will be described later. Therefore, when the plunger 2 moves forward and backward, the register ring 6 engaged with the plunger 2 as the plunger 2 moves in the receiving groove 9 is also provided. Moving.

As shown in FIG. 4, the register ring 6 is composed of a C-shaped ring portion 6a and a base portion 6b and a tip portion 6c of an operation portion provided at both ends thereof, and the two base portions 6b and 6b cross each other in the middle. And is bent near the outer periphery of the housing and is continuous with the two ends 6c and 6c. To operable tip 6c of the register ring 6, and 6c from the outside, a portion of the other end 1 _E of the housing 1, the notches 7 of the U-shaped as shown in FIG. 2 is formed. As shown in FIG. 1, the base portion 6 b and the tip end 6 c of the operation portion are accommodated in the notch 7 in the initial set state in which the ring portion 6 a is wound around the plunger 2 in contact with the annular set wall 12 a described above. The end portions 6 _E and 6 _E are formed so as to protrude slightly from the other end 1 _CE of the housing.

Further, as shown in FIG. 1, the tip 6c of the register ring 6 is bent downwardly toward the other end of the housing 1, and its length, however, the length along the length direction of the plunger 2 is provided. L ₁ (not an oblique length) is set to be larger than a length L ₂ from the end wall 9b of the ring housing portion 9 to the back wall 7a of the notch 7 in the initial set state (L ₁ > L ₂ ). By setting the shape and length of the base portion 6b of the register ring 6 in this way, the register ring 6 is prevented from being assembled in the reverse direction.

  The register ring 6 has an inner diameter of the ring portion 6a smaller than an inner diameter of the housing inner peripheral surface (cylinder chamber 1a diameter) (inner diameter of the second stopper) in the natural state (in a state where the diameter is not expanded), and the ring. The outer diameter of the part 6a is formed larger than the inner diameter of the opening end. As a result, it is possible to prevent the register ring 6 from coming off.

  The chain tensioner A having the above-described configuration is assembled in the initial set state shown in FIG. 1, and the return spring 3 is elastically engaged by mutual engagement between the set wall 12a, the register ring 6, and the end wall 9b (second stopper). The jumping-out of the plunger 2 by force is restricted, and safety during transportation until assembly is ensured. When the chain tensioner A in the initial set state is attached to the engine block and the operating portion of the register ring 6 is pressed and contracted to expand the diameter of the ring portion 6a of the register ring 6, the engagement state between the set wall 12a and the register ring 6 is increased. Canceled. Therefore, the plunger 2 advances outward by the elastic force of the return spring 3, presses the chain via a chain guide (not shown), and puts the chain in a tensioned state.

At this time, the ring portion 6a of the register ring 6 is fitted into any of the engagement grooves 11a to 11f. Thereafter, the pushing force to the rear is exerted on the plunger 2 by the tension of the chain during operation of the engine, when this pushing force exceeds the resultant force of the hydraulic pressure supplied elastic force and the hydraulic damper chamber 8 _D of the return spring 3, The plunger 2 and the register ring 6 are retracted to a position where the resultant force and the pushing force are balanced. This backward movement is a shock absorbing function of the hydraulic oil filling the hydraulic damper chamber 8 _D, takes place slowly. While the plunger 2 is retracted, the register ring 6 first shrinks in diameter while sliding on the tapered surface of the engagement groove 11, and engages with the engagement surface (lock wall) of the engagement groove 11. Retracts together with the plunger 2 while being engaged. With the retraction of the plunger 2, the excess hydraulic fluid in the hydraulic damper chamber 8 _D is leaking out of the housing through a small gap between the inner peripheral surface and the outer peripheral surface of the plunger 2 housing.

  On the other hand, when slack occurs in the chain, the plunger 2 moves forward by pressing the return spring 3 and the supply hydraulic pressure. As the plunger 2 advances, the register ring 6 advances integrally with the plunger 2, and after the ring portion 6a contacts the second stopper, the diameter of the register ring 6 increases while sliding on the tapered surface. When the chain is stretched over time and the plunger 2 further moves forward, the ring portion 6a of the register ring 6 is fitted into the rear engaging groove, and thereafter the same operation is performed.

  When the engine is stopped, the plunger 2 may be pushed in due to the cam stop position. For example, on an uphill road, if the change lever is in the forward gear, or if it is stopped with the back gear on the downhill, the chain is tensioned, so the plunger 2 is pushed in greatly. Even in this case, since the outer diameter of the ring portion 6a of the register ring 6 is smaller than the inner diameter of the first stopper 9a, the register ring 6 engaged with the engaging surface of the engaging groove engages with the first stopper 9a, This restricts further forward and backward movement of the plunger 2 (return movement restriction). In this case, the chain only loosens by the amount corresponding to the retraction amount of the plunger 2, and therefore, the chain does not loosen greatly even when the engine is restarted, and the chain fluttering immediately after starting converges quickly. Thus, it is possible to avoid such a situation that the chain is detached from the sprocket, or tooth skipping or abnormal noise is generated.

  When the chain is removed due to maintenance around the engine or the like, the plunger 2 tends to pop out due to the elastic force of the return spring 3, but even in that case, the ring portion 6a of the register ring 6 is fitted into the safety groove 10 and is attached to the safety wall. Since the engaged ring portion 6a engages with the second stopper 9b to restrict the plunger 2 from coming off (disassembly restriction), it is reliably prevented that parts such as the plunger 2 and the return spring 3 fall off the housing 1. The If you want to separate the plunger 2 from the housing 1, you can easily achieve this by pinching the tip 6c of the register ring 6 to increase the diameter of the ring portion 6a and releasing the engagement between the ring portion 6a and the safety wall 10. can do.

  According to the chain tensioner according to the present invention, the initial set state, the return movement restriction, and the disassembly restriction can be performed only by the register ring 6, and these functions can be performed by using a plurality of ring members and clips as in the conventional product. Compared to realization, the number of parts and manufacturing costs can be greatly reduced, the groove structure of the plunger 2 is simplified, and each groove is formed on the outer peripheral surface of the plunger 2 which is easy to process. Further, the advantage that the plunger 2 can be removed from the housing 1 with a simple operation and the maintainability is good retains that of Patent Document 1.

  The chain tensioner of the present invention is configured to prevent erroneous incorporation of a register ring provided for a plunger in a housing, and is widely used in a chain system for driving a camshaft of a vehicle engine.

Main sectional view of the chain tensioner of the embodiment Partial plan view Side view of view III-III in FIG. Enlarged perspective view of register ring

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 1a Cylinder chamber 2 Plunger 2a Hollow part 3 Return spring 4 Check valve 4a Check ball 4b Valve seat 4c Retainer 5 Communication path 5a Communication chamber 5b Channel 6 Register ring 6a Ring part 6b Base part 6c Tip 7 Notch 8 Pressure chamber 9 Ring housing groove 9a Tapered surface 9b End wall 10 Safety groove 11 (11a to 11f) Annular engagement groove 12 Annular protrusion 12a Set wall

Claims (3)

A cylinder chamber is formed in the housing, and a plunger slidably inserted into the cylinder chamber and a spring inserted into the hollow portion of the plunger to press the plunger outward are provided. A check valve is provided in the path of the oil supply passage to connect the oil supply passage to the formed pressure chamber and prevent backflow of the hydraulic oil sent thereby, and a plurality of engagement grooves are arranged on the outer periphery of the plunger and spaced apart in the axial direction. A ring receiving groove is formed on the inner periphery of the opening of the cylinder chamber, and a ring portion that can be engaged with the engaging groove and a ring portion that is elastically deformable in the radial direction of the register ring having the operating portion are received in the ring receiving groove. The engagement groove is a tapered surface that expands the diameter of the ring when the plunger protrudes, and an engagement that engages the ring when the plunger is retracted to prevent the plunger from moving backward. In the chain tensioner formed by the above-described structure, the pusher force applied to the plunger by the hydraulic oil from the oil supply passage is buffered. The operation portion is formed so that the tip of the operation portion protrudes from the housing, and the length L ₁ of the operation portion is set to be longer than the length L ₂ from the ring receiving groove end to the notch back wall. Chain tensioner register ring built-in structure.   The chain tensioner register ring built-in structure according to claim 1, wherein the notch is formed in a U-shape in a plan view in a part of the housing opening end.   3. The register ring built-in structure for a chain tensioner according to claim 1, wherein bases of the operation portions of the register ring are arranged so as to intersect each other and the tip is bent in an L shape near the outer peripheral position of the housing.

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