Belt tensioner

Abstract

To provide a belt tensioner capable of being used for a long period of time and prolonging its replacement period.SOLUTION: A belt tensioner 1 comprises: an oscillation body 20 that slides against a timing belt of an automobile and applies tension to the belt; a base body 10 that includes a support part 11 that supports the oscillation body 20; a coil spring 30 that is sandwiched between the base body 10 and the oscillation body 20; and a donut-shaped metallic coil spring pressing body 40 that is sandwiched between the base body 10 and the coil spring 30. In order to prevent the temporarily assembled belt tensioner 1 from being separated, a temporary fixing screw 50 is provided that is screwed and fixed into the support part 11 from above the oscillation body 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a belt tensioner that applies tension to a timing belt or the like of an automobile. [Background technology]

[0002] Belt tensioners used in automobiles require periodic replacement because their functionality decreases due to localized wear on the sliding surface and deterioration over time (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-100542 A Summary of the Invention [Problem to be solved by the invention]

[0004] The replacement of belt tensioners used in automobiles requires extensive disassembly and assembly for some models (for example, models equipped with an Alfa Romeo (registered trademark) TB1750i engine), which increases the cost of the replacement work.

[0005] In view of the above, there is a demand for a belt tensioner that can be used for a long period of time and whose replacement interval can be extended.

[0006] Therefore, an object of the present invention is to provide a belt tensioner that can be used for a long period of time by suppressing wear on the sliding parts.

[0007] Incidentally, the autotensioner in Patent Document 1 mentioned above is a tensioner that aims to ensure its durability by preventing foreign matter from entering the tensioner, and is considered to have a different approach to problem-solving than the belt tensioner of the present application. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a belt tensioner that includes a swinging body that is journalled on a support shaft constituting a base body and swings within the elastic range of a coil spring, in which a donut-shaped coil spring pressing body made of metal (preferably a metal that does not hydrolyse) is sandwiched between the base body and the coil spring, and an engagement groove is provided on the outer circumferential surface of the coil spring pressing body, through which an end of the coil spring passes.

[0009] In order to solve the above-mentioned problems, the present invention further provides a belt tensioner in which inclined portions are provided on both sides of a base end of the locking groove on the outer circumferential surface of the coil spring pressing body.

[0010] Also, in order to solve the above-mentioned problems, the present invention provides a belt tensioner in which the outer peripheral surface of the coil spring pressing body has one locking groove. Effect of the Invention

[0011] The belt tensioner of the present invention is a belt tensioner that includes a swinging body that is journalled on a support shaft that constitutes a base body and swings within the elastic range of the coil spring, and a donut-shaped metallic coil spring pressing body is sandwiched between the base body and the coil spring, and an engagement groove is provided on the outer circumferential surface of the coil spring pressing body, through which the end of the coil spring passes, thereby suppressing wear at the points that slide against the end of the coil spring and enabling longer use than conventional belt tensioners.

[0012] The belt tensioner of the present invention further provides inclined portions on both sides of the base end of the locking groove on the outer peripheral surface of the coil spring pressing body. This reduces contact and sliding between the coil spring pressing body and the coil spring, and is expected to further suppress wear at the points of sliding with the coil spring end.

[0013] Furthermore, the belt tensioner of the present invention has only one locking groove on the outer peripheral surface of the coil spring pressing body, which makes it possible to reduce processing and manufacturing costs and provide the belt tensioner at a lower price. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is an external view showing the overall configuration of a belt tensioner. [Diagram 2] FIG. 2 is an exploded view showing the overall configuration of the belt tensioner. [Diagram 3] FIG. 3 is an exploded view of the base body, the bearing portion, and the coil spring. [Figure 4] FIG. 4 is an exploded view of the swinging portion. [Diagram 5] FIG. 5 is a front view of the coil spring pressing body. [Figure 6] FIG. 6 is a cross-sectional view of the coil spring pressing body. [Figure 7] FIG. 7 is a right side view showing the locking groove of the coil spring pressing body. [Figure 8] FIG. 8 is a diagram showing the belt tensioner in use when installed in an automobile. [Figure 9] Figure 9 is a diagram showing how the belt tensioner works. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] It is implemented as a belt tensioner that applies tension to an automobile timing belt (drive belt). EXAMPLES

[0016] The belt tensioner (1) is composed of a specified base body (10) placed on the bottom, a support shaft portion (11) protruding upward from the bottom surface of the base body, a oscillating body (20) that is journaled on the support shaft portion and slides against a timing belt and oscillates due to the load of the timing belt, a coil spring (30) that is sandwiched between the base body and the oscillating body, and a donut-shaped metallic coil spring pressing body (40) that is sandwiched between the base body and the coil spring (FIGS. 1 and 2).

[0017] The base body (10) includes the support shaft portion (11) that supports the rocking body (20) (FIG. 2).

[0018] Although the support shaft portion (11) is provided integrally with the base body (10), it may be structured so as to be fixed to the base body as long as it does not move together with the swinging body (20).

[0019] The outer circumferential surface of the oscillator (20) is provided with projections and recesses corresponding to the timing belt in order to suppress slippage of the timing belt that contacts the outer circumferential surface of the oscillator (FIGS. 1 and 4).

[0020] The coil spring (30) has an outer diameter smaller than the outer diameter of the coil spring pressing body (40) (FIGS. 2 and 3).

[0021] One end (31) of the coil spring (30) is engaged and fixed to the oscillator (20) (not shown), and the other end (32) of the coil spring (30) passes through a locking groove (41) of the coil spring pressing body (40) and is secured to the base body for use (FIG. 3).

[0022] Therefore, the swinging body (20) swings within the elastic range of the coil spring (30) while being supported by the support shaft portion (11).

[0023] The coil spring (30) is made of metal.

[0024] The donut shape of the coil spring pressing body (40) has an inner diameter slightly larger than the outer diameter of the support shaft portion and an outer diameter slightly larger than the outer diameter of the coil spring (30) (Figures 2, 3, 5, and 6).

[0025] FIG. 6 is a cross-sectional view showing a cross section obtained by cutting the coil spring pressing body (40) in FIG. 5 in the vertical direction along a vertical line passing through the center of the coil spring pressing body (40) (FIG. 6).

[0026] The coil spring pressing body (40) has an outer circumferential surface provided with a locking groove (41) through which an end of the coil spring (30) passes (FIG. 7).

[0027] On both sides of the base end of the engagement groove (41) of the coil spring pressing body (40), there are inclined portions to reduce contact and sliding between the coil spring pressing body and the end of the coil spring (30) (Figure 7).

[0028] Regarding the material of the coil spring pressing body (40), an aluminum-based metal that does not hydrolyze is used in order to prevent the coil spring pressing body from wearing down due to the operation of the coil spring (30), which elastically deforms with the oscillation of the oscillator (20).

[0029] Although it is acceptable to use metals other than aluminum, it is considered preferable to select a metal harder than the coil spring. Also, in order to enable long-term use, it is preferable to use at least a metal that does not hydrolyze.

[0030] The coil spring pressing body (40), together with the swinging body (20), is pivotally supported by the support shaft portion (11) so as to be capable of swinging freely (FIGS. 2 and 3).

[0031] In order to prevent the temporarily assembled belt tensioner (1) from coming apart due to the elastic force of the coil spring (30) during transportation and before installation, a temporary fixing screw (50) is provided which screws into the support shaft portion (11) from above the rocker (20) to fix the belt tensioner (1) (FIG. 2).

[0032] Next, the operation of the belt tensioner will be described with reference to FIGS. 1, 2 and 9.

[0033] When an engine output shaft (61) of an automobile is operated, a drive pulley (62) attached to the engine output shaft rotates in a certain direction (FIG. 9).

[0034] When the drive pulley (62) starts to rotate, the drive belt (63) suspended around the drive pulley also starts to operate in response (FIG. 9).

[0035] Additionally, the plurality of driven pulleys (64) around which the drive belt (63) is wound and the belt tensioner (1) for applying tension to the drive belt also start to operate (FIG. 9).

[0036] When a load is generated on the belt tensioner (1) via the drive belt due to factors such as a change in the driving force of the engine output shaft and the drive pulley, a change in operating speed, a change in rotation direction, or slippage of the drive belt, the oscillating body (20) oscillates within the elastic range of the coil spring (30) (FIGS. 1 and 2).

[0037] Although a certain amount of wear may occur at the sliding points of the belt tensioner as the rocking body (20) rocks, the provision of a predetermined donut-shaped metallic coil spring pressing body reduces the degree of wear compared to conventional belt tensioners, thereby preventing wear on the sliding surface from progressing locally.

[0038] Therefore, the belt tensioner of the present invention can be used for a long period of time and the replacement interval can be extended. [Industrial Applicability]

[0039] INDUSTRIAL APPLICABILITY The present invention is an excellent belt tensioner that can be used for a long period of time and whose replacement cycle can be extended, and therefore has industrial applicability. [Explanation of symbols]

[0040] 1 Belt tensioner 10 Basic body 11 Support shaft 20. Rocking Body 30 Coil spring 31 One end of coil spring 32 Other end of coil spring 40 Coil spring pressure body 41 Locking groove 50 Temporary fixing screw 61 Engine output shaft 62 Pulley attached to the output shaft of the engine 63 Drive belt 64 Driven pulley

Claims

1. A belt tensioner including a rocker that is supported by a support shaft that constitutes a base body and rocks within an elastic range of a coil spring, A donut-shaped metal coil spring pressing body (40) is sandwiched between the base body (10) and the coil spring (30), The belt tensioner further comprises a locking groove (41) provided on the outer peripheral surface of the coil spring pressing body, through which an end of the coil spring passes.

2. 2. The belt tensioner according to claim 1, wherein an inclined portion is provided on both sides of a base end of the engagement groove (41) on the outer circumferential surface of the coil spring pressing body.

3. 3. The belt tensioner according to claim 1, wherein the number of locking grooves (41) on the outer circumferential surface of the coil spring pressing body is one.

Images