JP3329609B2 - Tensioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tensioner for applying an appropriate tension to a chain or a belt provided in an engine, and more particularly, to locking a plunger in a retracted position before assembling the tensioner. The present invention relates to a tensioner having a locking structure that can be used.

[0002]

2. Description of the Related Art Generally, a tensioner is
The housing includes a housing, a plunger slidably supported in the housing, and a coil spring that constantly biases the plunger in a protruding direction. The spring force of the coil spring causes the tip of the plunger to press against the tensioner arm. It is supposed to.

Further, in order to facilitate the assembly of the tensioner to the engine, there has been proposed a tensioner having a locking member capable of holding the plunger in a retracted state before the assembly. One end of the locking member is rotatable while being supported by the housing, and the other end is adapted to be removably locked to a locking pin fixed to the plunger.

When assembling a tensioner having such a locking structure, the plunger is retracted in advance,
The locking member is locked to the locking pin of the plunger, and the plunger is held in the retracted state. Next, the tensioner is assembled in the engine, and after the assembly is completed, the locked state between the locking member and the locking pin is released. Then, the tip of the plunger is pressed against the tensioner arm by the spring force of the coil spring.

In the conventional structure, one end of the locking member is in a free state after the tensioner is mounted on the engine. Therefore, during operation of the engine, the locking member vibrates with the vibration of the engine. Or oscillate, and even perform a swirling motion. As a result, during operation of the engine, the locking member interferes with other members to generate abnormal noise, and after a long operation, the locking member wears out, and in extreme cases,
There is a possibility that the locking member may fall off the housing.

Therefore, in order to solve such a conventional problem, a biasing means for biasing the locking member to a locking release position where the locking state with the locking pin is released is provided, and the tensioner is assembled. Later, the present applicant has proposed a tensioner having a locking structure capable of restraining the locking member at the unlocked position by the biasing force of the biasing means (Japanese Patent Application No. 6-2).
No. 83000)

[0007] According to such a tensioner, the free movement of the locking member during the operation of the engine can be suppressed, and the generation of abnormal noise during the operation of the engine can be prevented.

However, in the above structure, since the locking member is attached to the outside of the tensioner, the space occupied by the entire tensioner is slightly increased, so that other parts may be restricted in design. obtain.

The present invention has been made in order to solve such a conventional problem, and an object of the present invention is to provide a tensioner which can not only prevent generation of abnormal noise during operation of the engine but also reduce the size of the whole. And

[0010]

According to the present invention, there is provided a tensioner having a retractable plunger in a housing. The tensioner has a plunger hole formed in the housing for accommodating a rear end of the plunger. A locking sleeve that allows axial movement and rotation of the plunger is rotatably supported , and a locking pin protruding from an outer peripheral surface of the plunger is attached to a rear end of the plunger in the housing. With
The locking sleeve includes a first axial groove in which the locking pin can move, and a second groove intersecting the first groove and capable of engaging with the locking pin in a retracted position of the plunger. Are formed, and the second groove moves forward.
The inclined grooves extending in a direction away from each other said first groove
It is characterized by having.

[0011]

According to the tensioner of the present invention, before assembling to the engine, the locking pin attached to the rear end of the plunger engages in the second groove formed in the locking sleeve. Thus, the plunger is held at the retracted position. When the engagement between the locking pin and the second groove is released after the assembly to the engine is completed, the plunger moves in the axial direction and protrudes. Since it is arranged in the groove and can move in the axial direction, it does not hinder the movement of the plunger.

In this case, since the locking sleeve functioning as a locking member is inserted into the plunger hole formed in the housing, the entire tensioner can be reduced in size. In addition, before and after assembly to the engine, the locking sleeve is kept inserted in the plunger hole, so that the locking sleeve does not interfere with other parts during engine operation and noise is generated. Occurrence can be prevented.

Further , in this case, the locking pin is
The plunger is in the retracted position by engaging in the second groove of the leave.
When the plunger tip is pressed against the tensioner arm and the tensioner is slightly pushed in when the assembly is mounted on the engine from the held state , the locking pin contacts the inclined groove of the locking sleeve and locks. The pin exerts a force on the locking sleeve in a direction to rotate the locking sleeve.
At this time, since the locking sleeve is rotatably supported in the plunger hole, the locking sleeve is rotated by the force applied from the locking pin.

By the rotational movement of the locking sleeve, the locking pin moves from the second groove into the first groove. As a result, when the assembly to the engine is completed, the engagement state between the locking pin and the locking sleeve is released, and as a result, the plunger moves in the axial direction and protrudes, and presses against the tensioner arm.

Thus, when assembling to the engine,
Since the engagement state between the locking pin and the locking sleeve is automatically released, the assembling is easy and the work efficiency can be improved.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 6 are views for explaining a hydraulic tensioner according to an embodiment of the present invention. FIG. 1 is a front view showing an example of an engine timing system employing the hydraulic tensioner, and FIG. 2 is a hydraulic tensioner. 3 is a sectional view of FIG. 3, FIG. 4 is a locking sleeve of the hydraulic tensioner, (a) is a plan view, and (b) is a side view. The cross section of the locking sleeve in FIG. 3 is taken along the line III-III in FIG. 5 and 6 are diagrams for explaining the operation of the hydraulic tensioner.

FIG. 1 shows a timing system for a DOHC engine, which comprises a drive sprocket 3 fixed on a crankshaft 2.
And driven sprockets 6 and 7 fixed to the two camshafts 4 and 5, respectively, and a timing chain 8 wound between the sprockets. The arrow a in the figure indicates the direction of rotation of the crankshaft 2.

On the loose side of the timing chain 8, a hydraulic tensioner 10 for applying a pressing force to the timing chain 8 via a tensioner arm 9 is arranged.

As shown in FIGS. 2 and 3, the hydraulic tensioner 10 has a hole (plunger hole) 1 having an opening at one end.
1a is formed in the housing 11 and the rear end of the
A plunger 12 having a contact portion 12a at the distal end which is inserted into the inside 1a and abuts on the tensioner arm 9;
And a coil spring 13 for urging the plunger 12 in the protruding direction.

A support member 15 for slidably and rotatably supporting the plunger 12 is press-fitted into the opening of the hole 11a of the housing 11. One end of the coil spring 13 is pressed against the end face of the support member 15, and the other end is pressed against the end face of the contact portion 12a.

At the rear end of the plunger 12 in the hole 11a, a retaining pin 28 for preventing the plunger 12 from falling out of the hole 11a is implanted. The upper end of the pin 28 projects from the outer peripheral surface of the plunger 12.

A locking sleeve 40 for allowing the plunger 12 to slide and rotate is rotatably supported in the hole 11a. The locking sleeve 40, as shown in FIG.
It has a notch (first groove) 41 extending in the axial direction,
The width s of the notch 41 is formed slightly larger than the diameter of the pin 28. A groove (second groove) 42 extending in a direction intersecting the notch 41 is formed in the locking sleeve 40. The width of the groove 42 is formed to be substantially the same as the width s of the notch 41.

The groove 42 is formed as shown in FIGS.
The inclined groove 4 intersects with the notch 41 on the rear end side (left end side in each drawing) of the locking sleeve 40 and extends away from the notch 41 as it goes forward (rightward in each drawing).
2a, and a parallel groove 42b extending substantially in parallel with the notch 41 from the tip of the inclined groove 42a.

Before assembling the hydraulic tensioner 10 to the engine, the pin 28 of the plunger 12 is engaged with the distal end of the parallel groove 42b of the locking sleeve 40, whereby the plunger 12 is held at the retracted position. It has become so.

An oil chamber 20 partitioned by the plunger 12, the support member 15, and the like is formed in the hole 11a. The oil chamber 20 is connected to an external hydraulic circuit (not shown) including an oil pump. Is supplied.

An oil reservoir 25 for collecting and storing splashed oil in the engine is provided above the housing 11. The oil reservoir 25 is constituted by an open recess 25a formed on the upper part of the housing 11. Between the oil reservoir 25 and the oil chamber 20,
It is connected by an oil passage 26 via a check valve 30.

Next, the operation of assembling the tensioner 10 to the engine will be described. Before assembling to the engine, first, the plunger 12 is set to the retracted position where the pin 28 is engaged with the tip of the parallel groove 42b of the locking sleeve 40 (see FIG. 5).

From this state, the tensioner 10 is attached to the engine from the side (left side in FIG. 1). That is, the tensioner 10 is inserted into a recess formed in the engine side wall.
The tensioner 10 is mounted on the engine by bolting the flange 11b to the engine side wall.

At the time of assembling the engine, the abutting portion 12a at the tip of the plunger is pressed against the tensioner arm 9 with the tightening of the bolt, and the plunger 12 is gradually retracted (see the dashed line in FIG. 5). As a result, the pin 28 at the rear end of the plunger also moves rearward (to the left in the figure),
8 moves into the inclined groove 42a.

When the bolt is further tightened in this state, the plunger 12 is further contracted, and the pin 28 is pressed against the inclined groove 42a. As a result, the pin 28 applies a force to the locking sleeve 40 to rotate the notch 41 in the direction in which the notch 41 moves upward in FIG. At this time, the locking sleeve 40 is rotatably supported in the hole 11a.
0 rotates.

By the rotational movement of the locking sleeve 40,
The pin 28 gradually moves from the inside of the inclined groove portion 42a to the notch 41 side. When the bolt is completely tightened (ie, when the bolt is completely assembled to the engine), the pin 28 is notched.
1 and the engagement between the pin 28 and the groove 42 is released (see the dashed line in FIG. 6). Then, the coil spring 13
, The plunger 12 protrudes forward and presses against the tensioner arm 9. Thus, the assembling work is completed.

When the plunger 12 projects,
Since the pin 28 is disposed in the notch 41 and moves in the axial direction (see the solid line in the figure), the pin 28 does not hinder the movement of the plunger 12.

In this case, the locking sleeve 40 functioning as a locking member is provided in the hole 11 formed in the housing 11.
Since the tensioner is inserted in a, the entire tensioner can be downsized. In addition, before and after assembly to the engine, the locking sleeve 40 is kept inserted into the hole 11a, so that the locking sleeve 40 does not interfere with other parts during operation of the engine. Generation of abnormal noise can be prevented.

Moreover, in this case, the engagement state between the pin 28 and the groove 42 of the locking sleeve 40 is automatically released when assembling to the engine, so that assembling is easy. Work efficiency can be improved.

Further, since a pin for retaining the plunger 12 is used as the pin 28, there is no need to separately provide a locking pin, thereby reducing the number of parts.
It can contribute to cost reduction.

In the above embodiment, the locking sleeve 40 is used.
Is rotatably supported in the hole 11a of the housing 11, but the application of the present invention is not limited to this.
The present invention can be similarly applied to a case where the locking sleeve 40 is fixed to the hole 11a so as not to rotate.

FIG. 7 shows a preferred embodiment of a hydraulic tensioner having such a fixed locking sleeve, and FIG. 8 shows a timing system of a DOHC engine employing the hydraulic tensioner. . In each of the drawings, the same reference numerals as those in the above-described embodiment indicate the same or corresponding parts.

The hydraulic tensioner 10 'shown in FIG. 7 has substantially the same configuration as the hydraulic tensioner 10 of the above-described embodiment, except that holes for bolt insertion are formed instead of flanges as members for mounting the engine. Is that the leg member 14 is attached to the housing 11 '.
Different from 0. That is, the hydraulic tensioner 10
Is a type which is different from the above-mentioned embodiment and is attached from the front direction of the engine (upward in FIG. 8).

When assembling the hydraulic tensioner 10 'to the engine, the hydraulic tensioner 10' is inserted into the engine from the front with respect to the engine, and the bolt inserted into the leg member 14 is tightened. When the engagement between the pin and the groove of the locking sleeve is released after the assembly to the engine is completed, the operator forcibly forces the plunger 1
This is done by slightly rotating 2. As a result, the pin moves into the notch of the locking sleeve, and as a result, the plunger 12 protrudes in the axial direction and presses against the tensioner arm 9.

In this case, since the locking sleeve is fixed so as not to rotate, before the engine is assembled to the engine,
A locking sleeve can serve as a detent for the plunger 12. This eliminates the need for positioning the contact portion 12a of the plunger 12 with respect to the tensioner arm 9 when assembling the engine, and as a result, assembling is facilitated and work efficiency can be improved.

Further, in the above-described embodiment, an example in which the present invention is applied to a hydraulic tensioner is shown. However, the present invention can be similarly applied to tensioners other than the hydraulic tensioner.

[0042]

As described above, according to the tensioner of the present invention, the locking sleeve functioning as a locking member is inserted into the plunger hole formed in the housing, so that abnormal noise during engine operation is obtained. Not only can be prevented, but also the overall size can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of an engine timing system employing a hydraulic tensioner according to an embodiment of the present invention.

FIG. 2 is a front view of the hydraulic tensioner.

FIG. 3 is a sectional view of FIG. 2;

4A is a plan view of a locking sleeve inserted into the hydraulic tensioner, and FIG. 4B is a side view thereof.

FIG. 5 is a diagram for explaining the operation of the hydraulic tensioner when assembling the engine.

FIG. 6 is a view for explaining the operation of the hydraulic tensioner when assembling the engine.

FIG. 7 is a front view of a hydraulic tensioner according to another embodiment of the present invention.

FIG. 8 is a front view showing a state where the hydraulic tensioner (FIG. 7) is employed in the timing system (FIG. 1).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Hydraulic tensioner 11 Housing 11a Hole (plunger hole) 12 Plunger 28 Pin (locking pin) 40 Locking sleeve 41 Notch (first groove) 42 Groove (second groove) 42a Inclined groove 42b Parallel groove

Continuation of front page (56) References JP-A-8-145130 (JP, A) JP-A-8-4861 (JP, A) JP-A-2-180332 (JP, A) JP-A-8-121557 (JP) , A) Hira 5-10849 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H ^7/ 00-7/24 F02B 67/06

Claims (1)

(57) [Claims] 1. A tensioner having a retractable plunger in a housing, wherein a plunger hole formed in the housing for accommodating a rear end of the plunger permits axial movement and rotation of the plunger. Locking sleeve can rotate freely
A support pin is provided at the rear end of the plunger in the housing, and a lock pin protruding from an outer peripheral surface of the plunger is attached to the lock sleeve. a first groove in the direction, with intersecting grooves of the first, at the retracted position of the plunger and the locking pin is formed and the second groove to engage, said second groove , Forward
Extend in a direction away from the first groove
A tensioner having an inclined groove .