JP2001050056A - Tensioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress characteristic fluctuations of a tensioner having first and second shaft members screwed therewith by forming a rear end portion of the first shaft member and a receiver thereof into shapes such that they slidably contact in a continuous line or with a continuous face. SOLUTION: A tensioner 1 adjusts tension of a timing chain mounded on an automobile and the like by oscillating a curved chain guide which abuts to the timing chain according to advancing/retracting movement of the tentioner 1. The tensioner 1 comprises first and second shaft members 3, 4 respectively which are screwed therewith. The first shaft member 3 is configured to be rotationally energized by a torsion spring 8. A small-diameter boss portion 3f at the rear end of the first shaft member 3 is formed with a slot portion as fastening means and is fitted in a receiver 7. The rear end portion of the first shaft member 3 and the receiver 7 are formed into shapes such that they slidably contact in a continuous line or with a continuous face to secure stable operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tensioner for keeping the tension of an endless belt or a chain constant.

[0002]

2. Description of the Related Art A tensioner is a device that keeps the tension of an endless belt or chain used for an automobile or a motorcycle constant when the belt or chain is stretched or loosened. Hereinafter, a structure of a typical tensioner used for an engine portion of an automobile or a motorcycle will be described.

FIG. 7 is a partially cutaway view showing an example of a mounting layout of a tensioner mounted on an engine body. That is, this engine 5
At 0, an endless timing chain 53 is hung between a pair of cam sprockets 51 and a crank sprocket 52. The tensioner 1 has a timing chain 5
3 has a curved chain guide 10 which abuts on and guides the chain guide 10. The chain guide 10 has a base 11
Can be swung around the fulcrum. Then, the second shaft member 4 that expands and contracts the tensioner 1 pushes and pulls the chain guide 10 to swing, thereby adjusting the tension of the timing chain 53.

FIG. 8 is a longitudinal sectional view showing details of the tensioner 1 as an example shown in FIG. In the figure,
Inside the case 2, the first and second shaft members 3,
4 is assembled and inserted. Case 2 is shown in FIG.
It is attached to the engine body as shown in
A flange 6 having a mounting hole 5 for this purpose is formed to extend outward.

[0005] The first and second shaft members 3 and 4 are assembled by attaching an external thread 3 a to the outer peripheral surface of the first shaft member 3.
On the other hand, a female screw portion 4a is formed on the inner peripheral surface of the second shaft member 4, and these screw portions 3a, 4a are screwed together. The assembled first and second shaft members 3 and 4 are supported in the case 2 by fitting a rear end 3c of the first shaft member 3 to a shaft receiving member 7 as the receiving portion. You.

[0006] One end 8a of the torsion spring 8 has a first end.
Sliding part (slit) 3 formed on shaft member 3 of
d, and the other end 8b is locked at a predetermined position of the case 2. With such a configuration, when a device such as a driver is inserted into the sliding portion 3d and rotated during assembly, an initial torque is applied to the torsion spring 8, and the first torque is applied by the biasing force of the applied initial torque. Of the shaft member 3 is rotated.

The second shaft member 4 has a cylindrical shape, and a substantially half portion of the front side of the first shaft member 3 is inserted in a screwed state. The second shaft member 4 includes a bearing 9
The bearing 9 is fixed to the distal end portion of the case 2 and is formed with a substantially oval-shaped sliding hole 9a. The outer periphery of the second shaft member 4 is formed in the same shape as the sliding hole 9a. Therefore, the second shaft member 4 is connected to the sliding hole 9 a of the bearing 9.
, The rotation of the second shaft member 4 is restrained.

In such a structure, even if the first shaft member 3 is rotated by the rotational urging force of the torsion spring 8,
The second shaft member 4 screwed to the first shaft member 3 does not rotate. For this reason, the rotation urging force of the torsion spring 8 is converted into the propulsion force of the second shaft member via the rotation of the first shaft member 3, and the second shaft member 4 advances. As a result, the second shaft member 4 presses the timing chain through the chain guide 10 to apply a constant tension thereto. That is, the second shaft member is pressed by an external input load input from a timing chain, a belt, or the like, and tries to retreat,
The tension operation is performed by the balancing action of the tensioner trying to push it back.

The tensioner 1 shown in FIGS. 7 and 8 is a push-acting type which operates in the direction of pushing the timing chain or the like, but a tension-acting type tensioner which operates in the direction of pulling the timing chain or the like. There is also.

The operating characteristics of such a screw type tensioner are determined by the following factors. Screw Lead Angle Contact Status of Shaft End Face Friction Coefficient of Sliding Surface Spring Force Here, "return torque value (= T)" as an index indicating operation characteristics (movability) will be described. As shown in FIG. 6A, the return torque value is such that a weight (W) having a predetermined weight is placed on the tensioner 1 and a torque measuring tool is inserted into a sliding portion 3d formed on the first shaft member 3. Therefore, the resistance torque value when the motor is rotated at a constant speed is referred to as "return torque value (= T)".

Here, when the above-mentioned factor is fixed, the following relationship is established. Contact resistance of shaft end face High ← → Low Return torque value Large ← → Low In addition, the following relationship exists between return torque value and operation smoothness. Operating characteristics Difficult to move ← → Easy to move Return torque value large ← → Small In other words, good operating characteristics = Low return torque Heavy operational smoothness = Return torque large Afterwards, return to good operating smoothness and weight Torque value (= T)
Expressed by

FIG. 6B is a graph conceptually showing a transition of the return torque value from the initial use of the screw type tensioner to the end of the end of life, which is the product life, and the graph shown by the two-dot chain line is the conventional specification. It is a tensioner. As can be seen from this figure, generally, the conventional tensioner has a feature that the return torque value is maximum at the beginning of use and then decreases.

FIG. 9A is a partial perspective view showing the rear end 3c of the first shaft member 3 upside down.
FIG. 9B is a perspective view in which a part of the shaft receiving member 7 which receives the fitting of the rear end portion 3c is cut away.
(C) is a detailed partial cross-sectional view of a state where the rear end of the first shaft member 3 is fitted to the shaft receiving member 7, and as shown, the rear end of the first shaft member 3 is shown. Part 3c
Is formed with a sliding portion 3d which is notched over both ends of a diameter passing through the axis and extends over a predetermined length in the axial direction. The shaft receiving member 7 has a hole 7a at the center thereof. Therefore, the shaft receiving member 7
When the rear end 3c of the first shaft member 3 is fitted to
The bottom surface 3e of the first shaft member 3 and the shaft receiving member 7
The upper surface 7b of the contact member comes into contact with a width from the contact outer diameter φD to the contact inner diameter φd, and slides in rotation.

[0014]

In this case, the sliding portion 3d formed on the first shaft member 3 also comes into contact with the upper surface 7b of the shaft receiving member 7 and rotates. It has been confirmed by experiments and the like that the presence of the influence on the operation characteristics of the tensioner, that is, the operation characteristics of each tensioner differs depending on the formation state of the sliding portion 3d. In the conventional tensioner, it was necessary to consider this characteristic change in the specification setting. Therefore, in the present invention, the sliding portion 3d formed on the first shaft member 3 and the shaft receiving member 7 are configured so as not to directly contact and slide with each other. It is an object of the present invention to realize a tensioner in which a change in operation characteristics is small during the operation.

[0015]

According to the present invention, in order to solve the above-mentioned problems, the first shaft member and the second shaft member screwed by a screw portion are provided. A spring for urging the one shaft member in one direction, and a receiving portion that slides by directly or indirectly contacting the rear end of the first shaft member; A case for accommodating a second shaft member, wherein the tensioner restrains the rotation of the second shaft member and converts the rotational urging force of the spring into a unidirectional propulsion force of the second shaft member. The rear end portion of the first shaft member and the receiving portion are formed so as to be slid in contact with a continuous line or surface.

As described above, since the first shaft member and the shaft receiving portion come into contact with each other at a continuous line or surface,
Since the sliding portion does not come into contact with the receiving portion, the characteristic variation of the tensioner is reduced.

According to the second aspect of the present invention, there are provided a first shaft member and a second shaft member screwed by a screw portion, and a spring for urging the first shaft member to rotate in one direction. A case that has a receiving portion that slides by directly or indirectly contacting the rear end portion of the first shaft member and that houses the first shaft member and the second shaft member; An end of the spring is locked to the first shaft member in a tensioner that restricts rotation of the second shaft member and converts the rotational urging force of the spring into a unidirectional propulsion force of the second shaft member. A means for tightening the spring is provided on an end face of the first shaft member, and the means for tightening the first shaft member is provided in a state where the means for tightening does not contact a receiving portion provided on the case. Rear end Receiving portion of the case and is intended to be configured to directly or indirectly contact.

According to a second aspect of the present invention, the invention of the first aspect is more specifically described. However, similarly to the first aspect, the sliding portion as a spring tightening means is provided with a receiving portion. , So that the characteristic fluctuation of the tensioner is reduced.

According to a third aspect of the present invention, the winding means is a slit (sliding portion) or a concave portion formed on a rear end surface of the first shaft member. The tightening means is a portion which is locked when rotating the first shaft member to apply an initial torque to the spring, and inserts a driver-like device into the slit or the concave portion to rotate.

According to a fourth aspect of the present invention, a shaft receiving member is interposed between a rear end of the first shaft member that contacts and slides and a receiving portion of a case. The invention according to claim 5 is characterized in that a boss is protruded in the axial direction at a rear end of the first shaft member, and the means for tightening is formed on the boss. I do. The invention according to claim 6 is characterized in that a locking portion for locking one end of the spring is formed on a side surface of a rear end portion of the first shaft member. In the related art, one end of the spring is locked by a winding slit formed at the rear end of the first shaft member. It is provided.

[0021]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a view showing a first embodiment, FIG. 1A is a longitudinal sectional view of a tensioner 1 according to the first embodiment, and FIG. 1B is a view of a first shaft member 3. FIG. 1 is a partial perspective view in which the rear end 3c is turned upside down.
(C) is a perspective view showing a part of the shaft receiving member 7 cut away. The tensioner shown in FIG. 1A is common in the basic part to the tensioner shown in FIG. 8 and the like showing the conventional technique, and the same reference numerals are assigned to the same names.

Referring to FIG. 1, a tensioner 1 according to the first embodiment has a concentric circular shape from an axial center at a rear end 3c of a first shaft member 3, as is apparent from FIG. 1 (b). A boss 3f protruding outward is formed in a columnar shape. A sliding portion (slit) 3d is formed in the boss 3f as the means for tightening. When the boss portion 3f is fitted to the shaft receiving member 7 as the receiving portion, the boss portion 3f moves from the hole 7a formed in the shaft receiving member 7 as is apparent from the cross-sectional view of FIG. Protrude outward. Thereby, the first shaft member 3 and the shaft receiving member 7 come into contact with each other, and the bottom surface 3e around the boss 3f of the first shaft member 3 and the shaft receiving member 7
Of the upper surface 7b. That is, the contact is made by mutually continuous lines or surfaces.

Since the boss 3f is provided so as to protrude and the sliding portion 3d is formed on the boss 3f as described above, the torsion spring 8 which has conventionally been wound and locked around the sliding portion 3d is locked. One end 8a (see FIG. 8) forms a locking hole 3g in the axial direction on the side surface of the rear end 3c of the first shaft member 3 as the locking portion for locking one end of the spring,
One end 8a of the torsion spring 8 is inserted and locked in the locking hole 3g (see FIG. 3).

As described above, in this embodiment, since the sliding portion 3d does not come into contact with the shaft receiving member 7 as in the conventional tensioner, the return torque value is reduced as described above. The fluctuation amount is small. The solid line graph shown in FIG. 6B conceptually shows the characteristic change of the tensioner according to the first embodiment. It can be confirmed that there is little characteristic fluctuation from the end of the test to the end of the endurance.

FIG. 2 is a partial longitudinal sectional view showing the second embodiment, and a boss 3 at the rear end of the first shaft member 3 is shown.
A sliding portion 3d is formed in f, and has an inclined bottom surface 3e whose diameter gradually increases upward from the boss portion 3f. The shaft receiving member 7 is in contact with and fitted to the inclined bottom surface 3e. The bottom surface 3e and the top surface 7b are in contact with each other and slide along a continuous line or surface. The lower part of the shaft receiving member 7 is open, and the shaft receiving member 3 is open.
Boss portion 3f projects downward.

In this embodiment, a pin 14 is inserted into the side surface of the rear end 3c of the first shaft member 3, and a part of the pin 14 is projected from the side to form the locking portion. One end 8a of the torsion spring 8 is wound around the projection. As described above, the locking portion for locking the one end 8a of the torsion spring 8 is not limited to this embodiment.
What is necessary is just to be able to lock.

FIG. 3 is a partial longitudinal sectional view showing a third embodiment, in which a shaft receiving member 7 has a step-like step connecting from a lower small diameter portion to an upper large diameter portion. The rear end 3c of the shaft member 3 has a step having a small diameter with the lower boss 3f in a shape to be fitted to the shaft receiving member 7 having the step. And the shaft receiving member 7
The upper surface 7b and the bottom surface 3e of the first shaft member 3 are in continuous contact and sliding with each other. The small diameter portion below the shaft receiving member 7 has a deep cylindrical shape and is open, and a boss portion 3f formed on the first shaft member 3 is formed.
Has a configuration in which a sliding portion 3d is formed in the same manner as in the above embodiment, and does not protrude outward from the small diameter portion of the shaft receiving member 7.

FIG. 4 shows another embodiment. The tensioner of this embodiment comprises a first shaft member 3 and a second shaft member 4 screwed to the first shaft member 3.
The retaining tubular body 12 is attached to the outer peripheral portion of the torsion spring, and the torsion spring 8 is provided on the outer peripheral portion of the retaining tubular body 12. The torsion spring 8 is mounted over substantially the entire length in the axial direction inside the case 2, and one end 8 a of the torsion spring 8 is formed as the locking portion formed from the side surface of the rear end 3 c of the first shaft member 3 in the axial direction. And is locked by being inserted into the locking hole 3g. In this embodiment, a concave portion 3h having a polygonal inner peripheral surface is formed as the winding means formed on the rear end surface of the first shaft member 3. A rotating tool like a driver is inserted into the recess 3h, and the first shaft member 3 is rotated to apply an initial torque to the torsion spring 8. Since the concave portion 3h is formed to have a smaller diameter than the hole 7a of the shaft receiving member 7,
It does not contact or slide with the shaft receiving member 7, and therefore does not affect the rotation characteristics of the tensioner.

FIG. 5 is a view showing still another embodiment of the present invention, in which a cylindrical member 12 for retaining is provided on the outer peripheral portions of the first shaft member 3 and the second shaft member 4 assembled by screwing.
4 is the same as the embodiment shown in FIG. 4, but a leaf spring 13 is used in this embodiment as an elastic member for urging the first shaft member 3 to rotate. That is, the leaf spring 13 is provided at the base end portion of the first shaft member 3.
And one end 13 a thereof is locked in a locking hole 3 g as the locking portion formed in the first shaft member 3, and the other end 13 b is locked in a predetermined position of the case 2. The function of the leaf spring 13 is the same as that of the torsion spring 8.
The fitting portion between the rear end 3c of the first shaft member 3 and the shaft receiving member 7 is the same as that of the first embodiment, and a sliding portion 3d as the fastening means is formed. The boss portion 3f protrudes from the hole 7a of the shaft receiving member 7.

It should be noted that the present invention is not limited to the above embodiment, and it is obvious that those skilled in the art can take various forms based on the technical idea described in the claims.
For example, by appropriately selecting the members of the case 2,
Instead of using the shaft receiving member 7, the case 2 may directly receive the first shaft member 3, and may contact and slide with the first shaft member 3. The portion may be locked at another position other than the side surface of the first shaft member that does not hinder rotation, and such a configuration is also included in the scope of the present invention.

[0031]

As described above, according to the present invention, a spring tightening means such as a slit or a recess formed in the first shaft member 3 and the shaft receiving member 7 are in direct contact with each other.
Since it does not slide, there is little change in operating characteristics from the initial stage of equipment specifications to the end of durability, and stable characteristics are exhibited over a long period of time. Therefore, a screw tensioner that has a high degree of freedom in setting specifications in design Can be.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment, (a) is a longitudinal sectional view of a tensioner 1 according to the first embodiment,
(B) is a partial perspective view showing the rear end 3c of the first shaft member 3 turned upside down, and (c) is a shaft receiving member 7.
FIG. 2 is a perspective view with a portion cut away.

FIG. 2 is a partial longitudinal sectional view showing a second embodiment.

FIG. 3 is a partial longitudinal sectional view showing a third embodiment.

FIG. 4 is a longitudinal sectional view showing another embodiment.

FIG. 5 is a longitudinal sectional view showing still another embodiment.

6A is a longitudinal sectional view for explaining measurement of a return torque value in a conventional screw tensioner, and FIG. 6B is a conventional screw tensioner and a screw tensioner according to the present invention. 5 is a graph conceptually showing the transition of the return torque value from the beginning of use to the end of durability, which is the product life.

FIG. 7 is a partially cut-away view showing an example of a mounting layout of a tensioner attached to an engine body.

FIG. 8 is a longitudinal sectional view showing details of a conventional screw type tensioner.

FIG. 9A is a partial perspective view showing the rear end 3c of the first shaft member 3 turned upside down, and FIG. 9B is a shaft receiving member 7 which fits and receives the rear end 3c. (C) is a detailed partial cross-sectional view showing a state where the rear end of the first shaft member 3 is fitted to the shaft receiving member 7.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tensioner 2 Case 3 1st shaft member 3a Male screw part 3d Sliding part 3e Bottom surface 3f Boss part 3g Lock hole 3h Concave part 4 Second shaft member 4a Female screw part 7 Shaft receiving member 7a Hole 7b Top surface 8 Torsion spring 9 Bearing 12 Retaining tubular body 13 Leaf spring 14 Pin

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideshi Niwa 3131 Miyatamura, Kamiina-gun, Nagano Japan F-term (reference) 3J049 AA01 AA08 BB15 BB34 BC03 CA04 CA05

Claims (6)

[Claims] A first shaft member and a second shaft member screwed together by a screw portion; a spring for urging the first shaft member to rotate in one direction; and a rear end of the first shaft member. And a case for receiving the first shaft member and the second shaft member with a receiving portion that slides by directly or indirectly contacting the portion, and restricts rotation of the second shaft member. Wherein the rear end portion of the first shaft member and the receiving portion contact each other at a continuous line or surface. A tensioner characterized by being formed in a shape that slides. 2. A first shaft member and a second shaft member screwed together by a screw portion, a spring for urging the first shaft member to rotate in one direction, and a rear end of the first shaft member. And a case for receiving the first shaft member and the second shaft member with a receiving portion that slides by directly or indirectly contacting the portion, and restricts rotation of the second shaft member. A tensioner for converting the rotational urging force of the spring into a unidirectional propulsion force of a second shaft member, wherein one end of the spring is locked to the first shaft member and a coil for winding the spring is wound. First fastening means
The rear end portion of the first shaft member and the receiving portion of the case are directly or indirectly provided in a state where the winding means is not in contact with the receiving portion provided in the case. A tensioner characterized by sliding upon contact. 3. The tensioner according to claim 1, wherein the fastening means is a slit or a recess formed in a rear end surface of the first shaft member. 4. A shaft receiving member is interposed between a rear end portion of the first shaft member that contacts and slides and a receiving portion of a case. Or the tensioner according to the claim. 5. A boss portion is provided at a rear end portion of said first shaft member so as to protrude in an axial direction, and said means for tightening is formed on said boss portion. The tensioner according to claim 4. 6. The locking device according to claim 1, wherein a locking portion for locking one end of the spring is formed on a side surface of a rear end portion of the first shaft member. The tensioner described in Crab.