JP4304017B2 - Hydraulic auto tensioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic auto tensioner mainly used for adjusting the tension of a belt for driving an automobile auxiliary machine such as an alternator.
[0002]
[Prior art]
A pulley arm is swingably attached to a tensioner attachment target such as an engine block, the tension pulley is rotatably supported by the pulley arm, and the pulley arm is urged in the direction in which the tension pulley is pressed against the belt to keep the belt tension constant. As a hydraulic auto tensioner to hold, what was described in patent documents 1 is known conventionally.
[0003]
The above hydraulic auto tensioner inserts a rod into a cylinder filled with hydraulic oil, gives the rod an elastic force of a return spring, gives the rod an outward projecting property, and is loaded on the rod. The axial pushing force is absorbed by a hydraulic damper incorporated in the cylinder.
[0004]
In the hydraulic auto tensioner, a fixed coupling piece is provided at the closed end of the cylinder, a cylindrical fulcrum shaft is inserted into a shaft insertion hole formed in the fixed coupling piece, and the cylinder fulcrum shaft is inserted inside the fulcrum shaft. The fixed-side connecting piece is rotatably connected to the tensioner mounting target by tightening a bolt to be screwed into the tensioner mounting target.
[0005]
Also, a movable side connecting piece is provided at the tip of the rod, and the movable side connecting piece is rotatably connected to a pulley arm that supports a tension pulley by tightening a bolt.
[0006]
Here, if the contact between the shaft insertion hole of the fixed side connecting piece and the fulcrum shaft and the contact between the bolt insertion hole of the movable side connecting piece and the bolt are contact of metal touch, seizure may occur at each contact portion. For this reason, a sleeve made of rubber or synthetic resin is fitted between the contact portions.
[0007]
The hydraulic auto tensioner configured as described above is a gas-liquid two-phase hydraulic auto tensioner in which an air layer is provided on the hydraulic oil filled in the cylinder, so the rod needs to be assembled with the upward direction. If the rod is mounted in the reverse direction with the rod facing down, air cannot enter the pressure chamber of the hydraulic damper and the damper effect cannot be obtained, and the function as a hydraulic auto tensioner cannot be exhibited.
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-306860
[Problems to be solved by the invention]
By the way, in the conventional hydraulic auto tensioner, the fixed side connecting piece provided on the cylinder and the movable side connecting piece provided on the rod are rotatably connected by tightening bolts, and the connecting structure is as follows. Since both are the same, the hydraulic auto tensioner may be misassembled with the rod facing downward.
[0010]
In addition, in a hydraulic auto tensioner, normally, a bolt for connecting a connecting piece is transported in an assembled state where the bolt is inserted into an insertion hole provided in the connecting piece, but the bolt is simply inserted into the insertion hole. Therefore, it often dropped out at the stage of transportation before assembly.
[0011]
In order to prevent the bolt from falling off, it is effective to fit a cylinder having elasticity larger than the hole diameter of the insertion hole at the tip of the bolt protruding outward from the insertion hole. The problem is that the number of points increases and the cost increases.
[0012]
An object of the present invention is to prevent erroneous assembly of a hydraulic auto tensioner, and to prevent a bolt from dropping off at the stage of transportation before assembly.
[0013]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, in the present invention, a rod is inserted into a cylinder filled with hydraulic oil, and a return spring is provided to impart outward projecting property to the rod. A hydraulic damper that cushions the axial pushing force applied to the rod is provided, a fixed connection piece is provided at the closed end of the cylinder, and a tensioner is attached to the shaft insertion hole formed in the fixed connection piece by tightening a bolt. A swingable pulley arm that inserts a fulcrum shaft fixed to the object to prevent it from coming off, has a bolt insertion hole at the upper end of the rod, and supports the tension pulley by tightening the bolt inserted into the bolt insertion hole In the hydraulic auto tensioner provided with the movable side connecting piece that is rotatably connected to the bolt, a bolt that connects the movable side connecting piece to the pulley arm includes a bolt. A sleeve fixing bolt in which a sleeve made of a non-metallic material is fixed to the outer periphery of the straight shaft portion to be inserted into the G insertion hole, and the sleeve fixing bolt is in contact with the opening end of the bolt insertion hole on the outer periphery of the sleeve end A lip is provided to prevent the fixing bolt from coming off. Of the sleeve fixing bolt that connects the movable connecting piece to the pulley arm and the bolt that connects the fixed connecting piece to the tensioner mounting target, only the sleeve fixing bolt is set in the bolt insertion hole. The configuration that was set in advance was adopted.
[0014]
As described above, a sleeve fixing bolt is adopted as a bolt for connecting the movable side connecting piece to the pulley arm, and a lip capable of contacting the opening end of the bolt insertion hole is provided on the outer periphery of the sleeve end of the sleeve fixing bolt. Further, it is possible to prevent the sleeve fixing bolt from falling off at the stage of transportation before the assembly of the hydraulic auto tensioner.
[0015]
Here, the hydraulic auto tensioner is set in an assembled state by an automobile manufacturer. At the time of the assembly, the movable side connecting piece is connected to the pulley arm in the first step, and in the second step, the fixed side connecting piece is set as a tensioner mounting target. Connected. In the assembly, the sleeve fixing bolt is inserted into only the bolt insertion hole of the movable side connecting piece in advance, so that the sleeve fixing bolt is used for connection to the pulley arm in the first step. For this reason, it is possible to prevent the hydraulic auto tensioner from being installed upside down.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a pulley arm 1 is supported so as to be swingable about a shaft 2, and a tension pulley 3 rotatably supported at a swing side end of the pulley arm 1 is connected to the pulley arm 1. It is pressed against the belt 4 by the automatic tensioner 10.
[0017]
As shown in FIG. 2, the hydraulic auto tensioner 10 has an oil seal 12 attached to an upper opening of a cylinder 11 filled with hydraulic oil to provide an air layer on the hydraulic oil surface, and the oil seal 12 is slid. A hydraulic damper 14 is provided at the lower end portion of the rod 13 that freely passes through, and the elastic force of the return spring 15 is applied to the rod 13 to give the rod 13 outward protrusion.
[0018]
Here, the hydraulic damper 14 slidably incorporates a plunger 16 connected to the lower end of the rod 13 into a sleeve 17 fitted to the lower part of the cylinder 11, and a pressure chamber 18 formed below the plunger 16. And a reservoir chamber 19 provided above is communicated by a passage 20 formed in the plunger 16, and the passage 20 is opened and closed by a check ball 21. The check ball 21 closes the passage 20 when the pressure in the pressure chamber 18 becomes higher than the pressure in the reservoir chamber 19, and prevents the hydraulic oil in the pressure chamber 18 from flowing from the passage 20 to the reservoir chamber 19. Reference numeral 22 denotes a plunger spring that presses the plunger 16 against the rod 13.
[0019]
The return spring 15 is provided on the outer side of the cylinder 11, the lower end thereof is supported by a flange 23 provided at the lower outer periphery of the cylinder 11, and the upper end thereof is in contact with the flange 25 of the movable side connecting piece 24 attached to the upper end of the rod 13. In contact therewith, the rod 13 is given outward projecting properties.
[0020]
A fixed side connecting piece 26 is provided at the lower closed end of the cylinder 11, and a fulcrum shaft 28 is inserted into a shaft insertion hole 27 formed in the fixed side connecting piece 26.
[0021]
As shown in FIG. 4, the fulcrum shaft 28 has a cylindrical shape, and a sleeve 30 made of rubber or plastic is fixed to the outer periphery thereof by means of baking or bonding, and both end portions of the outer peripheral surface of the sleeve 30 are fixed. The fulcrum shaft 28 is prevented from coming off by contact between the annular projecting portion 31 provided at the opening and the opening ends of both ends of the shaft insertion hole 27.
[0022]
The fulcrum shaft 28 is fixed by screwing a bolt 32 inserted inside thereof into a tensioner mounting object 33 formed of an engine block, and the fixed side connecting piece 26 is rotatable around the fulcrum shaft 28. Yes.
[0023]
As shown in FIGS. 2 and 3, a bolt insertion hole 34 is formed in the movable side connecting piece 24, and a bolt 35 inserted into the bolt insertion hole 34 is screwed into a screw hole 36 formed in the pulley arm 1. Has been.
[0024]
The bolt 35 has a flanged head portion 35a at one end, and a sleeve 35d made of a non-metallic material such as rubber or plastic is baked on the outer periphery of a straight shaft portion 35c provided with a small-diameter screw shaft portion 35b at the other end. It consists of a sleeve fixing bolt fixed by means of bonding. The length of the straight shaft portion 35 c of the sleeve fixing bolt 35 is longer than the width dimension of the movable side connecting piece 24.
[0025]
In addition, annular lips 35e are provided at both ends of the outer peripheral surface of the sleeve 35d in the sleeve fixing bolt 35, and the sleeve fixing bolt 35 comes out of the bolt insertion hole 34 by the abutment of the lip 35e against the opening end of the bolt insertion hole 34. It has been stopped.
[0026]
The movable side connecting piece 24 is rotatably connected to the pulley arm 1 by screwing the screw shaft portion 35b of the sleeve fixing bolt 35 into a screw hole 36 formed in the pulley arm 1 and tightening it.
[0027]
In the hydraulic auto tensioner having the above-described configuration, when the tension of the belt 4 changes due to torque fluctuation and the belt 4 becomes slack, the rod 13 moves outward by the elastic force of the return spring 15, and the tension pulley 3. When the belt 4 is pushed, the slack of the belt 4 is absorbed.
[0028]
At this time, the plunger 16 moves upward together with the rod 13, and the pressure in the pressure chamber 18 becomes lower than the pressure in the reservoir chamber 19, so that the check ball 21 opens the passage 20, and the hydraulic oil in the reservoir chamber 19 passes through the passage. The rod 13 flows smoothly from the pressure chamber 18 to the pressure chamber 18, and the rod 13 moves rapidly outward to immediately absorb the slack of the belt 4.
[0029]
On the other hand, when the tension of the belt 4 increases, the rod 13 is pushed in the axial direction via the tension pulley 3 and the pulley arm 1. At this time, since the pressure in the pressure chamber 18 becomes higher than the pressure in the reservoir chamber 19, the passage 20 is closed by the check ball 21, and the pushing force is buffered by the hydraulic oil in the pressure chamber 18.
[0030]
When the pushing force is higher than the pressing force of the return spring 15, the hydraulic oil in the pressure chamber 18 leaks into the reservoir chamber 19 through a minute gap between the outer peripheral surface of the plunger 16 and the inner peripheral surface of the sleeve 17. The plunger 23 is slowly retracted to a position where the pressing force and the pressing force are balanced.
[0031]
Since the hydraulic auto tensioner 10 has a gas-liquid two-phase structure in which an air layer is provided on the hydraulic oil, it is necessary to assemble the rod 13 upward.
[0032]
Here, the assembly of the hydraulic auto tensioner 10 is carried out by an automobile manufacturer. When the hydraulic auto tensioner 10 is shipped to the automobile manufacturer, as shown in FIG. The hydraulic auto tensioner 10 is shipped in a state where the sleeve fixing bolt 35 is set in the hole 34 and the bolt 32 is not inserted into the fulcrum shaft 28 in the fixed side connecting piece 26.
[0033]
In the set state of the sleeve fixing bolt 35 with respect to the movable side connecting piece 24, the lip 35 e provided on the sleeve 35 a of the sleeve fixing bolt 35 can be brought into contact with the opening end of the bolt insertion hole 34. The sleeve fixing bolt 35 is prevented from falling off during the transportation stage. For this reason, it is not necessary to fit a cylinder having elasticity larger than the hole diameter of the bolt insertion hole 34 at the tip of the sleeve fixing bolt 35 to prevent the bolt from being removed, and the cylinder can be omitted. The number of points is reduced, and the cost can be reduced.
[0034]
When the hydraulic auto tensioner 10 is assembled by an automobile manufacturer, as shown in FIG. 5 (II), the movable side connecting piece 24 is connected to the pulley arm 1, and after the connection, in the next step, FIG. ), The fixed-side connecting piece 26 is connected to the tensioner attachment object 33 by tightening the bolt 32.
[0035]
When the hydraulic auto tensioner 10 is assembled as described above, if bolts are set in advance on each of the movable side connecting piece 24 and the fixed side connecting piece 26, the fixed side connecting piece 26 is connected to the pulley arm 1, and the hydraulic pressure is increased. There is a risk that the automatic tensioner 10 is reversely assembled.
[0036]
However, in the hydraulic auto tensioner 10 shipped to an automobile manufacturer, as shown in FIG. 5 (I), the arm is shipped with the sleeve fixing bolt 35 set only on the movable connecting piece 24. By removing the bolt from the assembly line connecting the hydraulic auto tensioner 10 to 1, the sleeve fixing bolt 35 is always employed. For this reason, reverse assembly of the hydraulic auto tensioner 10 can be completely prevented.
[0037]
Here, since the bolt for connecting the movable side connecting piece 24 to the pulley arm 1 is the sleeve fixing bolt 35 in which the sleeve 35a is integrated, the sleeve is inserted into the bolt insertion hole of the movable side connecting piece 24 and the inside of the sleeve is inserted. As compared with the case where the bolt is inserted into the bolt and the bolt is screw-engaged with the pulley arm to connect the movable side connecting piece to the pulley arm, the assemblability can be greatly improved.
[0038]
【The invention's effect】
As described above, in the present invention, the lip that can be brought into contact with the open end of the bolt insertion hole is inserted into the sleeve fixing bolt by inserting the sleeve fixing bolt in which the sleeve is fixed to the bolt insertion hole of the movable side connecting piece. By providing this, it is possible to prevent the sleeve fixing bolt from falling off at the stage of transportation before assembly of the hydraulic auto tensioner, and to improve the assembly performance of the hydraulic auto tensioner.
[0039]
In addition, since the sleeve fixing bolt is set only on the movable connecting piece, it prevents the hydraulic auto tensioner from being installed upside down when assembling the hydraulic auto tensioner at an automobile manufacturer. can do.
[Brief description of the drawings]
FIG. 1 is a front view of a belt tension adjusting device using a hydraulic auto tensioner according to the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 4 is an enlarged cross-sectional view of the lower part of the hydraulic auto tensioner shown in FIG. 2. FIG. 5 (I) to (III) are assembly stages of the hydraulic auto tensioner. Partially cutaway front view [Explanation of symbols]
11 Cylinder 13 Rod 14 Hydraulic damper 15 Return spring 24 Movable side connecting piece 26 Fixed side connecting piece 27 Shaft insertion hole 32 Bolt 33 Tensioner mounting target 34 Bolt insertion hole 35 Sleeve fixing bolt 35c Straight shaft portion 35d Sleeve 35e Lip

Claims (1)

A rod is inserted into a cylinder filled with hydraulic oil, a return spring is provided for the rod to project outwardly, and a hydraulic pressure is provided in the cylinder to buffer the axial pushing force applied to the rod. A damper is provided, a fixed-side connecting piece is provided at the closed end of the cylinder, and a fulcrum shaft fixed to the tensioner mounting target is inserted into a shaft insertion hole formed in the fixed-side connecting piece by bolt tightening to prevent the cylinder from coming off. The rod has a bolt insertion hole at the upper end of the rod, and a movable connecting piece is provided rotatably connected to a swingable pulley arm that supports the tension pulley by tightening the bolt inserted into the bolt insertion hole. In the hydraulic type auto tensioner, the bolt that connects the movable side connecting piece to the pulley arm is non-gold on the outer periphery of the straight shaft portion that is inserted into the bolt insertion hole. Consisting sleeve fixed bolt which is fixed a sleeve made of a material, the lip retaining the sleeve fixing bolt provided on the outer circumference of the end portion of the sleeve of the sleeve fixing bolts by abutting against the open end of the bolt insertion hole, the movable-side connecting piece A hydraulic auto-tensioner characterized in that only a sleeve fixing bolt is set in a bolt insertion hole among a sleeve fixing bolt that connects a pulley arm to a pulley arm and a bolt that connects a fixed side connecting piece to a tensioner mounting target .

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