JPH0654139B2 - Propulsion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a propulsion force applying device for applying a constant tension to a chain or a timing belt that drives a camshaft of an engine of a two-wheeled vehicle or a four-wheeled vehicle. It is a thing.

<Prior Art> A propulsive force applying device is used as, for example, a chain tensioner or a belt tensioner, and when the chain or the belt is stretched during use or is loosened due to wear, the chain or belt is pressed in a certain direction to a certain degree. However, it acts so as to have a characteristic close to that of a rigid body with respect to the reaction force in the direction opposite to the pressing direction.

5 and 6 show a vertical sectional view and a sectional view taken along the line VI-VI of a conventional example of this propulsive force applying device.

This propulsive force applying device includes a casing 1 in which an axial cavity 1a is formed, a rotary shaft 2 rotatably inserted into the base side (right end side in FIG. 5) of the casing 1, and a rotary shaft. A pressing body 3 that is screwed to the tip of 2;
The rotation shaft 2 is externally inserted, one end 4a is inserted into the engaging groove 2a of the rotation shaft 2, and the other end 4b is inserted into the long groove 1b on the front end side of the casing 1 to apply a rotation force to the rotation shaft 2. The torsion spring 44 and the seal bolt 6 screwed to the base end of the casing via the O-ring 5 constitute the main part. And the pressing body 3
A cap 8 made of an elastic material is fixed to the tip of the spring pin 7 by a spring pin 7, and the cap 8 is pressed against the chain or belt so that the chain or belt maintains a constant tension. Further, the pressing body 3 has a substantially oval outer periphery and is inserted into a bearing 9 in which a sliding hole of the same shape is formed so that the rotation is restricted, whereby the rotational force of the rotary shaft 2 is applied to the pressing body. The pressing body 3 is converted into the propulsive force of 3 to move out of the casing.

Such a propulsion force applying device twists the torsion spring 4 so as to apply a predetermined torque, inserts the rotary shaft 2 and the pressing body 3 into the casing 1, and then fixes the cap 8 to the pressing body 3. In this state, the tip portion (the left end portion in FIG. 5) of the casing 1 is inserted from the outer wall of the equipment such as the engine, and fixed by a bolt or the like for use. As a result, the rotating shaft 2 is rotated by the restoring force of the torsion spring 4, and this rotation causes the pressing body 3 to advance and press the chain or belt to exert a constant tension.

<Problems to be Solved by the Invention> However, in this conventional device, the casing 1
Since the base end side of is sealed with the O-ring 5 and the seal bolt 6, the sealability is good, but the tip side of the casing inserted into the device has poor sealability. That is, the long groove 1b into which the other end 4b of the torsion spring 4 is inserted,
C portion where the pressing body 3 and the bearing 9 are in contact, D portion where the bearing 9 is inscribed in the casing 1, E portion where the pressing body 3 and the cap 8 are in contact, A shaft portion F of the spring pin 7 for fixing the cap 8 and the spring Since the G portion where the pin 7 and the cap 8 are in contact with each other is not subjected to any sealing treatment, the sealing property of these portions is poor. Therefore, when the conventional device is used as it is, each member is corroded by the internal environment of the device, or foreign matter such as dust is mixed into the casing to cause biting, which causes malfunction. There is. Lubricating oil is applied to each member in order to maintain such a function, but the lubricating oil flows out at an early stage and the sealing property is still incomplete, and this is not a fundamental solution.

<Means for Solving Problems> The present invention provides a propulsion force imparting device which solves the above problems and improves the sealing performance inside the casing.

For this reason, the propulsion force applying device according to the present invention includes a rotary shaft that is inserted into a casing with both ends open and is urged to rotate by a spring force, and a cap that is inserted into the tip of the rotary shaft and screwed into the rotary shaft to rotate. A pressing body that slides in the axial direction by the rotation of the shaft, a bearing that engages with the distal end portion of the casing and slidably supports the rotation of the pressing body, and an inner diameter portion that contacts the outer surface of the pressing body. A flexible shield plate composed of an outer diameter portion in contact with the inner surface of the casing, which is narrowed between the bearing and the casing to close the tip opening portion of the casing, and a side opposite to the tip portion of the casing. It is characterized in that it is composed of a seal bolt screwed to the base end portion located at, and a seal material interposed between the pressing body and the cap and between the seal bolt and the casing.

<Embodiment> An embodiment of the present invention will be specifically described below with reference to a longitudinal sectional view shown in FIG. 1 and a sectional view taken along line II-II shown in FIG.

This propulsive force applying device has a casing 20 in which both ends are opened and a cavity 21 is formed in the axial direction, a rotary shaft 30 inserted into the cavity 21 of the casing,
Cylindrical pressing body 4 screwed onto the tip of the rotating shaft 30.
0, a stopper 50 and a seal bolt 60 attached to a base end portion (right end portion in the illustrated embodiment) located on the side opposite to the tip end portion of the casing 20, a torsion spring 70 for rotating the rotary shaft, and And a bearing 80 that supports the pressing body 40.

The casing 20 is composed of a horizontally long tubular portion 22 and a flange portion 23 that is continuously provided on the front end side of the tubular portion 22 in an orthogonal manner. Mounting holes 24 are formed above and below the flange portion 23, and devices such as an engine (not shown) are shown. It is designed to be fixed with bolts to the outer wall. In this attached state, the flange portion 23
Is located outside the device, and the front end side (left side in FIG. 1) of the flange portion 23 is located inside the device. Both the front end portion (left end portion in FIG. 1) and the base end portion (right end portion in FIG. 1) of the tubular portion 22 of the casing 20 are opened, and the rotary shaft 30, the pressing body 40, and The torsion spring 70 is inserted, while the stopper 50 and the seal bolt 60 are attached to the base end opening.

The rotary shaft 30 includes a large diameter portion 31 and a small diameter portion 32, and a torsion spring 70 is externally inserted into the large diameter portion 31, and the small diameter portion 3
The pressing body 40 is screwed onto the second member 2. Here, in the screwing with the pressing body 40, the male screw portion 33 is engraved on the outer peripheral surface of the small diameter portion 32, and the male screw portion is screwed on the female screw portion 41 engraved on the inner peripheral surface of the pressing body 40. It is done by that. Further, the torsion spring 70 externally inserted in the large diameter portion 31 has one end 71 at the large diameter portion 3
1 is inserted into the engaging groove 34 formed in the axial direction from the base end surface of the first end, and the other end 72 is bent in an L shape so as to extend in the front end direction of the casing. A long groove 25 into which the other end 72 is inserted is formed in the casing 20, and when the torsion spring 70 is assembled by being twisted to give a predetermined torque, the rotary shaft is restored by the restoring force of the torsion spring 70. 30 is designed to rotate.

The pressing body 40 is inserted into the hollow portion 21 of the casing 20 while being screwed into the small diameter portion 32 of the rotary shaft 30, and the intermediate portion is supported by the bearing 80.

The bearing 80 is inserted from the front end opening portion of the casing 20 and abuts on the step portion 25 formed inside the casing 20. The outer peripheral portion of the bearing 80 is, as shown in FIG.
It is engaged with the three end grooves 27 formed in the 0 end opening. That is, the tip opening of the casing 20 is formed with three tip grooves 27 on the circumference, the diameters of which are increased at equal intervals, and the bearing 80 has the same shape as the tip opening. Is to be fitted to. A substantially oval sliding hole is formed in the bearing 80, and the outer peripheral shape of the pressing body 40 is formed in the same shape as the sliding hole, and the rotation is restricted by being inserted into the sliding hole. Therefore, even if the rotary shaft 30 rotates, the pressing body 40 does not rotate, but is converted into the propulsive force of the pressing body 40 to slide the pressing body 40. The sliding of the pressing body 40 is performed so as to project to the outside of the casing 20, but the rotating shaft 30 is reversely rotated against the torsion spring 70 to rotate the pressing body 40.
The spacer 90 for restricting the sliding range in the opposite direction of the pressing body 40 when pulling back into the casing 20 and resetting.
Is provided. The spacer 90 includes a tubular portion 91 that is externally inserted into the pressing body 40, and a washer portion 92 that is continuously provided from the base end portion of the tubular portion 91 to the inside.
2 is located between the large-diameter portion 31 and the small-diameter portion 32 of the rotary shaft 30 and comes into contact with the base end surface of the pressing body 40,
Reverse sliding (sliding in the retracting direction) is suppressed.
Reference numeral 81 is a circlip for preventing the bearing 80 from coming off.

A cap 42 made of an elastic material or the like is fitted into the tip of the pressing body 40, and the cap 42 directly or indirectly abuts on a chain or belt in the device and presses it in a certain direction to loosen the chain or belt. Is being corrected. The cap 42 includes an insertion portion 42a and a flange portion 42b. The insertion portion 42a is inserted into the open front end portion of the pressing body 40 so that the flange portion 42b contacts the front end surface of the pressing body 40.

The stopper 50 attached to the base end portion of the casing 20 has a distal end portion which is the engagement groove 3 of the rotary shaft 30.
4 is inserted into the stopper groove 28 formed in the base end portion of the casing 20 so that the base end portion maintains the engaged state with the casing 20, and the stopper 50 is rotated by the engagement with the stopper groove 28. The shaft 30 is locked so as not to rotate. Also, this stopper 5
When 0 is pulled out from the stopper groove 28 and rotated with the tip inserted into the engagement groove 34, the rotary shaft 30 rotates in the same direction and the torsion spring 70 is wound and the rotational energy is stored. The seal bolt 60 is the casing 2
It is screwed to the base end portion of 0 to seal the inside of the hollow portion 21 of the casing 20 so that dust, water, etc. from the outside do not enter. Therefore, the seal bolt 60 is formed with a flange portion 61 that covers the base end portion of the casing, and is screwed into the base end opening portion of the casing 20 via the O-ring 62 that is a sealing material. The seal bolt 6
0 is the casing 20 after the stopper 50 is pulled out.
Used by screwing.

In such a propulsion device, the casing 2
Shield plate 10 for closing the opening at the tip of 0
0 is attached. FIG. 3 and FIG. 4 show a front view and a central longitudinal sectional view of the shield plate 100. The shield plate 100 is made of a flexible material such as rubber or plastic, and the inner diameter portion 101 is formed in a substantially oval shape having the same shape and size as the pressing body 40, and the outer diameter portion 102 is the tip of the casing 20. It has the same shape as the opening. That is, the outer diameter portion is formed with three pieces of lip portions 103 which are fitted into the front end groove 27 of the front end opening portion of the casing at equal intervals. By being formed in this way, when the outer diameter portion 102 is fitted into the tip end opening portion of the casing 20 while the inner diameter portion 101 is externally inserted into the pressing body 40,
The inner diameter portion 101 contacts the outer surface of the pressing body 40, and the outer diameter portion 102
Is in contact with the inner surface of the casing 20 to seal the gap between the pressing body 40 and the casing 20. Further, as shown in FIG. 4, circumferential grooves 105 and 106 having a V-shaped cross section are formed in the inner diameter portion 101 and the outer diameter portion 102. When the shield plate 100 is pressed due to the formation of the circumferential grooves 105 and 106, the diameter of the inner diameter portion 101 is reduced, the close contact with the pressing body 40 is strengthened, and the diameter of the outer diameter portion 102 is increased, so that the casing 20. Adhesion to the inner surface is strengthened. Such shield plate 10
0 is interposed between the step portion 26 formed in the casing 20 and the bearing 80, but the outer diameter portion 102 has the outer diameter portion 102 and the bearing 8.
And the inner diameter portion 101 is narrowed by the spacer 9
The above-mentioned adhesion is embodied by being narrowed by 0 and the bearing 80. Further, a sealing material 110 composed of an O-ring is provided between the pressing body 40 and the cap 42. The sealing material 110 is fitted into the insertion portion 42a of the cap 42 from the outside, and the cap 42
When is inserted into the pressing body, it is interposed between the insertion portion 42a and the pressing body 40 to seal between them. By mounting the seal member 110 and the shield plate 100 as described above, the tip opening of the casing 20 is sealed, and dust, water, oil, etc. in the device do not enter the casing, and the mechanical member in the casing is prevented. Since it does not adhere, there is no corrosion of the mechanical members or biting of foreign matter, and reliable use is possible for a long period of time.

In the assembly of the present embodiment configured as described above, the torsion spring 70 is inserted into the hollow portion 21 from the tip end opening of the casing 20, and the rotary shaft 30, the pressing body 40, and the spacer 9 are inserted.
Insert in the same way with the combination of 0 and stopper 50
Is rotated to apply a predetermined torque to the torsion spring 70. Next, after the shield plate 100 and the bearing 80 are externally fitted to the pressing body 40 and fixed by the circlip 81, the cap 42 is attached to the pressing body 40. Then, in this state, the tip portion of the casing is inserted into a device such as an engine, and the flange portion 2
By fixing 3 to the device and removing the stopper 50, the rotating shaft 30 is rotated by the torque of the torsion spring 70, and the pressing body 40 advances from the inside of the casing to press the chain, belt or the like. After removing the stopper 50, the base end of the casing located outside the device is sealed by the seal bolt 60 and the O-ring 62.

In the above embodiment, the rotating shaft may be rotated by a spiral spring instead of a torsion spring.

<Effects of the Invention> As described above, according to the present invention, the front end opening of the casing, in which foreign matter such as dust is easily mixed, is closed by the shield plate, and the sealing material is interposed between the pressing body and the cap. It is possible to obtain a propulsive force applying device having improved reliability and high reliability.

[Brief description of drawings]

1 and 2 are a longitudinal sectional view and a sectional view taken along line II-II of one embodiment of the present invention, FIGS. 3 and 4 are a front view of a shield plate, a central longitudinal sectional view, and FIG. FIG. 6 is a vertical sectional view of the conventional device and a sectional view taken along line VI-VI. 20 ... Casing, 30 ... Rotating shaft, 40 ... Pressing body, 50 ... Stopper, 60 ... Seal bolt, 70 ... Torsion spring, 80 ... Bearing, 62,110 ... Sealing material, 100 ... Shield plate, 101 ... inner diameter part, 102 ... outer diameter part

Claims (1)

[Claims] 1. A rotary shaft which is inserted into a casing having both ends opened and is urged to rotate by a spring force, and a cap is inserted into a distal end portion of the rotary shaft and screwed into the rotary shaft to axially rotate the rotary shaft. A pressing body that slides on the casing, a bearing that engages with the tip end portion of the casing and slidably supports the rotation of the pressing body, and an inner diameter portion that contacts the outer surface of the pressing body and an inner surface that contacts the inner surface of the casing. A flexible shield plate, which is composed of an outer diameter portion and is narrowed between the bearing and the casing to close the front end opening portion of the casing, and a base end portion located on the opposite side of the front end portion of the casing. A propulsion force imparting device, comprising: a seal bolt screwed to the seal bolt; and a seal material interposed between the pressing body and the cap and between the seal bolt and the casing.