JP2562046B2 - Tensioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a tensioner that applies a constant tension to a chain or timing belt that drives a camshaft of an engine of a two-wheeled vehicle or a four-wheeled vehicle. .

[Prior Art] Tensioners such as chain tensioners and belt tensioners are
When worn or loosened, it is used to press a chain or belt in a certain direction to maintain a constant tension.

FIG. 6 shows a conventional tensioner disclosed in Japanese Utility Model Publication No. 62-19015. A cylindrical casing 1 that is attached substantially vertically by a fixing bolt hole 1a, a shaft-shaped rotating body 2 that is rotatably inserted into the casing 1, and a male screw portion 2a formed at the tip of the rotating body 2. A pressing body 3 that is screwed and propelled by the rotation of the rotating body 2, and a spring (torsion spring) 4 that is externally inserted to the rotating body 2 and applies a rotating force to the rotating body 2.
And a bearing 5 which has a non-circular bearing hole through which the pressing body 3 penetrates and which is fixed to the casing 1 and restrains rotation of the pressing body 3.
The main part is composed of and.

In such a configuration, when the pressing body 3 is brought into contact with a chain, a belt or the like in a state where the rotating body 2 is rotated and the spring 4 stores the rotational energy, the rotating body 2 is rotated by the spring 4 and the rotational force is increased. Is transmitted to the pressing body 3. However, since rotation of the pressing body 3 is restricted by the bearing 5, the pressing force of the rotating body 2 is converted into propulsion force to press the chain, the belt or the like. This makes it possible to maintain a constant tension without loosening the chain, the belt, or the like.

In such a tensioner, it is necessary to closely contact the inside of the casing 1 in order to prevent dust or the like from entering the casing 1 or to prevent the lubricating oil filled inside from leaking out. For this reason, the seal bolt 7 is screwed into the base end portion (lower end portion) of the casing 1, and the expandable bellows 6 is provided between the tip end portion (upper end portion) of the casing 1 and the pressing body 3 that is driven and driven. It is covered. The bellows 6 is attached such that the end portion on the pressing body 3 side is fitted into the concave portion of the pressing body 3 and the spring band 8 is provided on the outer side thereof.
Is wound, while the end portion on the casing 1 side is connected to the cap 9 press-fitted into the casing 1.

Reference numeral 10 in the figure is a stopper that locks the thrust of the pressing body 3, and is appropriately removed after the tensioner is mounted.

[Problems to be Solved by the Invention] In such a tensioner, the processing for mounting the bellows 6 is troublesome. That is, the cap 9 connected to the end of the bellows 6 on the casing side.
This is because the structure is press-fitted into the casing 1 to maintain airtightness, and it is difficult to control the dimensions of the cap and the casing for enabling press-fitting, and machining with high accuracy is required.

Therefore, it is an object of the present invention to provide a tensioner capable of attaching a bellows capable of maintaining airtightness without requiring highly accurate processing.

[Means for Solving the Problem] The present invention is configured such that a rotating body that is urged to rotate by a spring and a pressing body that is restricted in rotation by a bearing are inserted into a casing in a screwed state, and In a device for converting a rotational force into a propulsive force in an axial direction of a pressing body, a space between the pressing body and a casing is covered with a bellows, the bellows is integrated with a cap formed of a hard material, and the cap is A tensioner fitted to a casing with a seal ring interposed between the casing and the cap, and assembled by caulking the cap to the casing.

[Operation] In the above configuration, since the seal ring is inserted between the cap to which the ends of the bellows are integrally connected and the casing to which the cap is attached, the airtightness of the cap attachment portion is maintained. Has become. Also, since the cap is made of a hard material, the part that is hung on the casing becomes strong, and it does not break during abnormal work such as dropping the product.Furthermore, since the cap is attached to the casing by caulking, it is easy It does not come off and the sealing performance is guaranteed.

[Embodiment] FIG. 1, FIG. 2 and FIG. 3 show the overall construction of an embodiment of the present invention. The tensioner includes a casing 20 in which an axial cavity 21 is formed, a rotating body 30 and a pressing body 40 that are inserted into the cavity 21 of the casing 20 in a screwed state, and a rotational force is applied to the rotating body 30. Spring (torsion spring) 50 and casing 20
A bearing 60 attached to the tip (left end in FIG. 1) for restraining the rotation of the pressing body 40, and an expandable bellows 70 covering the casing 20 and the pressing body 40.

The present invention is a bellows mounting structure in such a tensioner.

In the present embodiment, the bellows 70 is stretched between the push shaft 43 of the pressing body 40 and the casing 20 to cover the space between them. At the end of the bellows 70 on the side of the pressing body 40, a ridge 71 is formed on the inner surface, and the ridge 71 is fitted into a recess 44 formed on the outer surface of the push shaft 43 correspondingly. . Then, the garter spring 72 is wound from the outside to seal the end portion on the pressing body 40 side. On the other hand, the end portion on the casing side is connected to the cap 73 attached to the casing 20.
Note that this connection can be performed by an appropriate means such as adhesion or welding. The cap 73 has an inner diameter that is substantially equal to the outer diameter of the casing 20 on the base side, and is made of a substantially cylindrical hard material with the tip part bent slightly inward, and after the base side is externally inserted into the casing 20, the cap 73 It is attached to the casing 20 by caulking a predetermined position on the outer peripheral surface of the. Bellows above
70 is connected to the bent portion at the tip of the cap 73. Further, a peripheral groove 26 is formed on the outer surface of the casing 20,
A seal ring 75 is wound around the circumferential groove 26. The seal ring 75 is made of an elastic body, and when the cap 73 is attached to the casing 20 while being wound around the circumferential groove 26, the cap 73
The inner surface and the outer surface of the casing 20 are brought into close contact with each other to seal between them. Therefore, invasion of dust from the outside and leakage of the lubricating oil sealed inside the casing 20 are prevented. With such a structure using the seal ring 75, the airtightness between the cap 73 and the casing 20 can be reliably performed.
Therefore, it is not necessary to press fit the cap for maintaining the airtightness of the mounting portion of the cap 73, and it is not necessary to have a high degree of dimensional accuracy for press fitting. Therefore, the processing can be easily performed and the productivity is improved.

The casing 20 is to be attached to a device (not shown) such as an engine, and a mounting hole 22 for that is formed in an outer portion. Further, a seal bolt 80 is screwed into the base end portion (the right end portion in FIG. 1) via a packing 81, and airtightness on the base end side is maintained.

The rotating body 30 is rotatably supported in the casing 20. The rotating body 30 is formed by connecting a male screw portion 31 on the tip end side and a shaft portion 32 on the base end side in a continuous manner, and the pressing body 40 is screwed onto the male screw portion 31 to transmit the rotational force. . Also, the shaft
32 is rotatably supported in a bearing recess 23 of the casing 20. In this case, a bottomed tubular bearing member 82 is provided between the shaft portion 32 and the bearing recess 23 of the casing. The support member 82 is inserted between the rotating body 30 and the casing 20 to support the rotation of the rotating body 30.
Since the rotary member 30 is smoothly and reliably supported by inserting the bearing member 82 in this manner, it is not necessary to process the bearing recess 23 of the casing 20 with high precision, and
Wear of the rotating body 30 and the casing 20 can be prevented.

The pressing body 40 has a pipe portion 42 having an internal thread portion 41 formed on the inner surface.
And a push shaft 43 fitted to the tip portion of the pipe portion 42. The pipe portion 42 meshes with the male screw portion 31 of the rotating body 30 to transmit the rotational force of the rotating body 30, and
It is inserted into the bearing 60 in a rotation-restrained state and converts the rotational force of the rotating body 30 into a propulsive force. Meanwhile, push shaft
As for 43, the tip part has advanced outward from the casing 20,
The tip end surface is brought into contact with a chain, a belt or the like directly or via a roller pressing them. Thereby, the tension of the chain, the belt and the like is maintained.

The spring 50 is fitted over the pressing body 40 and the rotating body 30. This spring 50 is externally inserted into the pressing body 40 and the rotating body 30 when they are in a screwed state. It has a structure. With such a triple structure, there is an advantage that the stroke of the pressing body 40 can be sufficiently secured even if the device length of the pressing body 40 in the advancing / retracting direction is shortened. Here, one end 51 of the spring 50 is bent and formed in a substantially L shape so as to engage with the casing 20, and the other end 52 thereof is a rotating body.
It is inserted into the split slit 33 of 30 to engage with the rotating body 30. Therefore, when the seal bolt 80 is removed and is inserted into the split slit 33 such as a driver from the outside of the casing 20 to rotate the rotating body 30, it is possible to store rotational energy in the spring 50. Incidentally, the end portion 53 of the spring 50 on the rotary member side is inserted in the split slit 33 of the rotary member 30 and then bent in the radial direction of the rotary member 30. The radial displacement described above can be prevented, and stable operation of the spring 50 is ensured.

The bearing 60 restrains the rotation of the pressing body 40, is retained by a circlip 61, and is attached to the tip of the casing 20. 4 and 5 show this bearing 60
And its mounting structure. In the bearing 60, a bearing hole 62 is formed in the central portion, and engaging pieces 63 are formed at 90 degree intervals in the outer portion. The bearing hole 62 is formed in a substantially oval shape in which both sides of the circle are cut in parallel, and the pipe portion 42 of the pressing body 40 having the same outer shape has the bearing hole 62.
By being inserted into 62, the pressing body 40 is restrained from rotating. On the other hand, the engagement piece 63 is for restraining rotation against the rotational force of the rotating body 30. Therefore, the engagement grooves 24 are formed at 90-degree intervals on the tip end surface of the casing 20 corresponding to the engagement pieces 63, and the rotation restraint is achieved by fitting the engagement pieces 63 into the engagement grooves 24. I am supposed to do it. In this case, the depth of the engagement groove 24 of the casing 20 is larger than that of the engagement piece 63, and the bearing 60 is attached in a state of being slightly retracted from the tip end surface of the casing 20. And
On the inner surface of the casing 20 protruding from the bearing 60, a clip groove 25 into which the circlip 61 is fitted is formed.

Further, a spacer 90 is inserted between the bearing 60 and the casing 20. The spacer 90 is inserted in the contact portion between the bearing 60 and the casing 20, and in particular, the portion of the bearing 60 corresponding to each engaging piece 63 is bent and formed in a U shape so as to wrap each engaging piece 63, As a result, it is inserted between the engagement piece 63 and the engagement groove 24 of the casing 20. Spacer with such a structure
90 is a wide surface of the spacer 90, which prevents the pressing force of the engaging piece 63 due to the rotational force of the rotating body 30 transmitted via the pressing body 40 from directly acting on the casing 20. Further, it is possible to prevent wear of the end surface of the engagement groove 24 of the casing 20. Thus, by using the spacer 90 for the bearing 60 and the supporting member 82 of the rotating body 30, the casing
20 can be made of a material such as aluminum or synthetic resin having poor wear resistance, and even in this case, the tensioner prevents wear of the casing 20 at the mounting portion of the bearing 60 and the bearing portion of the rotating body 30, which is a problem. It operates without any weight and can achieve weight reduction. In addition, one end 51 of the spring 50 is pulled out to a part of the engaging groove 24 of the casing 20 so as to engage with the casing 20 described above.

2 and 3, reference numeral 100 denotes a stopper, which locks the thrust of the pressing body 40 before the tensioner is assembled. The stopper 100 is to be removed after assembly.

In FIG. 1, 40a, 60a and 90a are pressing bodies 40,
A lubricating oil circulation path is provided in the bearing 60 and the spacer 90, and the lubricating oil filled inside by these lubricating paths 40a, 60a and 90a is circulated evenly inside the casing 20.

EFFECTS OF THE INVENTION As described above, according to the present invention, the seal ring is interposed between the cap to which the pressing body and the end of the bellows covering the casing are integrally connected, and the casing to which the cap is attached. In order to ensure the airtightness between the cap and the casing, it is not necessary to press-fit the cap into the casing, which eliminates the need for high-level machining, which facilitates processing and assembly.

Also, since the cap is made of a hard material, the part that is hung on the casing becomes strong, and it does not break during abnormal work such as dropping the product.Furthermore, since the cap is attached to the casing by caulking, it is easy It does not come off and the sealing performance is guaranteed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention, FIGS. 2 and 3 are plan views and side views thereof, and FIGS. 4 and 5 are perspective views and sectional views showing a bearing mounting structure. FIG. 6 is a sectional view of a conventional example. 20 …… Casing, 30 …… Rotating body, 40 …… Pressing body, 50 …… Spring, 60 …… Bearing, 70 …… Bellows, 73 …… Cap, 75 …… Seal ring.

Claims (1)

(57) [Claims] 1. A rotating body biased by a spring and a pressing body whose rotation is constrained by a bearing are inserted into a casing in a screwed state, and the rotational force of the rotating body is applied in the axial direction of the pressing body. In the device for converting into propulsive force, a space between the pressing body and the casing is covered with a bellows, the bellows is integrated with a cap formed of a hard material, and the cap forms a seal ring between the casing and the casing. A tensioner characterized by being fitted to a casing via the interposition and being assembled by caulking the cap to the casing.