DE19623485B4

DE19623485B4 - tensioner

Info

Publication number: DE19623485B4
Application number: DE19623485A
Authority: DE
Inventors: Kazumasa Yamatokoriyama Ayukawa
Original assignee: Gates Unitta Asia Co
Current assignee: Gates Unitta Asia Co
Priority date: 1995-06-14
Filing date: 1996-06-12
Publication date: 2006-08-24
Anticipated expiration: 2016-06-13
Also published as: DE19623485A1

Abstract

Belt tensioner with the following components:
a clamping shell (22) having an opening;
a clamping arm (30) having a lid portion (30b) formed at one end thereof, the lid portion (30b) being rotatably connected to the clamping cup (22) and extending so as to open the opening of the clamping cup (22 ) closes;
resilient biasing means (50) provided in said clamping cup (22) and acting between said clamping cup (22) and said clamping arm (30) to bias said clamping arm (30) in one of said directions of rotation; and
a damper member (32) fixedly secured to the lid portion (30b) of the clamp arm (30) such that an outer peripheral surface of the dam member (32) is in sliding contact with an inner peripheral surface of the clamp cup (22),
characterized in that
the cover portion (30b) of the tensioning arm (30) is provided with at least two rod-shaped peg-like elements (30a) which from there parallel to a pivot axis of the lid portion (30b) of the tensioning arm ...

Description

The The invention relates to a belt tensioner according to the preamble of claim 1, mainly and advantageously in a belt drive system of Automotive engine is used.

One Such belt tensioner is used to ensure a driving force safely transferred to, by preventing slipping when the driving force transferred to a variety of devices by a single belt becomes. This type of belt tensioner is for example in the JP 5-67854 U.

at a conventional one Belt tensioner, such as the one published in the above-mentioned publication is a tension arm has a lid portion at one end formed, wherein the lid portion rotatable with a fixed shell element connected, which is mounted in an engine block. The tension arm also has a pulley, which is attached to its other end, wherein the pulley is adapted to a belt a belt drive system for a Automotive engine leads. A torsion spring is provided in the fixed shell member and acts between the shell element and the tensioning arm, so that the tensioning arm is rotatably biased so that the pulley straining the belt.

Of the Clamping arm is with an annular damping element provided at its lid portion, and an outer peripheral surface of the damping comes with an inner peripheral surface of the fixed shell member in sliding contact. In particular, the annular damping element has some projections, the from its inner peripheral surface project and are arranged at suitable intervals, wherein the Protrusions with Grooves or recesses are in the lid portion are formed of the clamping arm, so that a relative movement between both is prevented. The annular damping also has a spring provided on its inner peripheral surface is, wherein the spring serves, the annular damping element against the fixed shell element pretension. The annular damping element that is elastically biased against the fixed shell element. This will while the rotation of the clamping arm a damping force or frictional force between the annular cushioning member and the fixed one Shell element generated and a rotational resistance is applied to the clamping arm applied.

Nevertheless relaxes at the above mentioned usual Belt tensioner when the outer peripheral surface of the annular damping is exposed to abrasion or wear, the annular damping, such that a peripheral portion of the damping member in the radial direction in terms of the lid portion of the clamping arm is movable. This creates a gap between the protrusions of the damping element and the grooves or depressions of the tensioner, causing the elements Sounds generate and beat against each other, etc., while the clamping arm pivotal movement performs. In short, is in the arrangement of the conventional Belt tensioner a secure and tight attachment of the damping element at the lid portion of the clamping arm directly through the abrasion or Wear of the damping damaged, causing a loosening of the damping element causing what is undesirably a relative movement between the damping element and the lid portion of the tensioning arm leads.

on the other hand is conventional the damping element often made of nylon or polyacetal. If nylon is used, there is a friction noise between the sliding contact surfaces of the damping element and the fixed shell element generated. Even if polyacetal is used, although no friction noise is generated, but the Polyacetaldämpfelement is subject to an early Abrasion and wear and tear is vulnerable for cracks at a point where stress is concentrated.

A generic belt tensioner is from the DE 35 12 376 A1 known. A clamping shell has an opening. A tensioning arm has a lid portion formed at one end thereof. The lid portion is rotatably connected to the clamping cup and extends to close the opening of the clamping cup. A resilient biasing means is provided in the clamping shell and acts between the clamping shell and the clamping arm to bias the clamping arm in one of the directions of rotation. A damper member is fixedly secured to the lid portion of the clamp arm so that an outer peripheral surface of the damper member is in sliding contact with an inner peripheral surface of the clamp cup.

Of the Invention is based on the object, a belt tensioner according to the preamble of claim 1 so that a damping force at the sliding contact surfaces The fixed clamping shell and the damping element are thus produced can that sounds repressed even if the damper element Abrasion and wear is subject.

These The object is achieved by a Belt tensioner solved with the features of claim 1.

The rod-shaped peg-like elements and the holes can be arranged at positions that are from a center of the damping element are offset. Preferably, the rod-shaped pin-like elements and the holes at equal intervals arranged in the radial direction from the center of the damping element.

Also has the damping element an insert section, the one piece with it is formed, with the holes in the insertion section are formed, and the insertion section of the damping element can be arranged along an inner periphery of the damping element. Preferably, the damping element an annular body on, with the insertion section of the damping element one piece from one side of the ring body extends. Furthermore, the annular body is divided so that therein a gap is formed and the insertion portion of the damping element arranged in the diameter direction on the side, which is the gap of the annular body is opposite.

Of the Belt tensioner may have at least one annular spring element, that in the damping element is arranged so that an outer peripheral surface of damping elastically biased against an inner peripheral surface of the clamping cup is. Preferably, the annular Spring as a C-shaped Ring spring formed. Also, the holes of the damping element are over the rod-shaped peg-like elements of the damping element over the Forming a gap and paying attention to the holes of the damping element and the rod-shaped cone-like Elements can a circular cross-section to have.

The The object and advantages of the invention will become better apparent from the following Description with reference to the accompanying drawings.
1 Fig. 10 is a schematic view showing a belt drive system of an automotive engine incorporating a belt pretensioner according to the present invention;
2 Fig. 10 is a side view showing an external appearance of the belt tensioner according to the present invention;
3 is a longitudinal sectional view of the belt tensioner of 2 ;
4 is an exploded view of a belt tensioner 3 ;
5 is a side view showing a tensioning arm of the belt tensioner 3 shows;
6 is a bottom view of the tension arm of the 5 ;
7 is a side view showing an annular damping element of the belt tensioner of 3 shows;
8th is a plan view of the annular damping element of 7 ;
9 is a plan view of a type of C-shaped annular spring;
10 Fig. 10 is a plan view showing another type of C-ring spring;
11 Fig. 11 is a plan view showing another embodiment of the annular dumbbell member;
12 is a perspective view of the annular Dämpfelements that in 11 is shown;
13 Fig. 12 is a schematic view showing a durability tester for testing a belt tensioner according to the present invention;
14 Figure 4 is a graph showing part of the durability test results performed by the durability tester; and
15 is a graph showing another part of the durability test results performed by the durability tester.
1 schematically shows a belt drive system of an automotive engine, in which a belt tensioner is installed according to the present invention. The belt drive system has a drive pulley 1 mounted on an output shaft of an automotive engine (not shown), a driven pulley 2 for an air compressor, a driven pulley 3 for a power steering pump, a driven pulley 4 for an alternator, freewheel pulleys 5 and 6 and a single drive belt 7 on, which is stretched around the pulleys. The belt tensioner according to the present invention, generally designated by the reference numeral 10 is indicated that it is provided with a part of the drive belt 7 between the pulleys 1 and 4 is engaged.
The belt tensioner 10 has a fixed element 20 , which is attached to an engine block, and a clamping disc 40 on, which pivotable about a pivot pin or a pivot shaft 23 with respect to the fixed element 20 is provided. The clamping disc 40 is in 1 biased upward by a biasing device, which in the fixed element 20 is provided, and the drive belt 7 is tensioned due to the biasing force resulting from the pretensioner. If the clamping disc 40 around the pivot pin 23 in a by a dashed line in 1 Moving position shown can be tensioning or guiding the belt 7 around the pulleys 1 to 6 easy to run.
2 shows an external appearance of the belt tensioner 10 , As shown in this figure, the fixed element comprises 20 a mounting section 21 , with two mounting holes 21a is formed, in the (not shown) bolts are inserted to be bolted to an engine block, and a clamping shell 22 in which a torsion or spiral spring 50 ( 3 ) is recorded. In the clamping shell 22 is a tension arm 30 rotatable on the pivot shaft 23 mounted and pivotable about its axis. The clamping disc 40 is rotatable about a disc bolt 41 provided by the tensioning arm 30 is stored, and the disc bolt 41 is parallel to the pivot shaft 23 , The tension arm 30 has an annular damping element or friction element 32 which is attached thereto, and an outer peripheral surface of the damping element 32 is in sliding contact with an inner circumferential surface of the clamping cup 22 ,
3 shows an internal structure of the belt tensioner 10 according to the present invention and 4 shows the main parts of the belt tensioner 10 in an exploded view. As shown in these drawings, the tensioner arm includes 30 a lid section 30b extending so that an opening surface of the clamping cup 22 is closed, and a disc mounting portion 30c , the disc 40 rotatably supports. The annular damping element 32 is safe on the lid section 30b attached and in sliding contact with the peripheral surface of the clamping shell 22 near their opening area.
The clamping shell 22 has a sublime section 22a , which is integrally formed at the center of its bottom, and the pivot pin 23 is in the sublime section 22a screwed. The pivot pin 23 has a threaded section 23a formed on its lower end portion and a hexagonal portion 23b which is formed approximately in the middle. The threaded section 23a of the pivot pin 23 gets into the sublime section 22a screwed, in which a suitable tool such as a wrench, a tensioner or the like on the hexagonal portion 23b is applied. Screwing in the threaded section 23a in the sublime section 22a is carried out until the hexagonal section 23b to the top of the raised section 22a abuts. This will cause the pivot pin 23 safely in the bottom of the clamping shell 22 used and connected.
The pivot pin 23 also has a circular bar section 23c that is different from the hexagonal section 23b extends upward and the circular rod portion 23c ends in a second threaded section 23d at its upper end ( 4 ). The circular bar section 23c is in a sleeve 31 inserted in a middle hole 30h is included in the lid section 30b of the tensioning arm 30 is trained. A mother 24 is on the second threaded section 23d of the pivot pin 23 screwed and thereby becomes an axial movement of the sleeve 31 prevented. Nonetheless, the sleeve can 31 slide in the direction of rotation against a given frictional resistance. This is the tension arm 30 around the pivot pin 23 with respect to the fixed element 20 pivotable. It should be noted that an upper O-ring and a lower O-ring above and below the pivot sleeve 31 can be inserted.
The torsion spring 50 is composed of a metal wire wound in a spiral shape. An end 51 the torsion spring 50 is at the bottom of the clamping shell 20 attached, and the other end 52 ( 4 ) is on the clamping arm 30 attached. The torsion spring 50 is in a suitably tensioned state between the clamping shell 22 and the tension arm 30 inserted and thereby is the tension arm 30 biased in the direction of rotation in one direction to the (in 2 and 4 not shown) to tension the drive belt, which over the clamping disc 40 is drawn. Of course, the thickness, the material, the shape, etc. of the metal wire of the torsion spring 50 appropriately selected in accordance with the required rotational biasing force.
As in 3 shown is the disc 40 rotatably on the disc mounting portion 30c of the tensioning arm 30 through the disc bolt 41 via an interposed ball bearing 42 attached. A dust shielding element 43 is between the head of the disc bolt 41 and the ball bearing 42 inserted, and thereby the penetration or entry of dirt, dust or the like in the ball bearing 42 be prevented.
The damping element or friction element 32 . that on the lid section 30b of the tensioning arm 30 is fastened, is formed of a suitable elastic material such as plastic or rubber. For example, it is made of polyacetal, nylon containing molybdenum for improving self-running properties, other polymer material, nylon reinforced with high-strength glass fibers, or carbon fiber-reinforced plastic, etc. Nevertheless, it is very preferable to use the damping element 32 of a partially aromatic polyamide plastic material such as polyhexamethylene terephthalamide or the like for the reasons mentioned later.
Two circular holes 32d are in the damping element 32 formed so as to extend in the axial direction, and are in the vicinity of the inner peripheral surface of the damping member 32 arranged. On the other hand, there are at least two projections or circular rod-like pins 30a from the lid portion 30b the clamping arm 30 in front and are in the circular holes 32d inserted substantially without a gap formed therebetween. An inner diameter of the circular holes 32d namely, is substantially equal to an outer diameter of the circular rod-like pin 30a , This allows the damping element 32 effective at a movement in both the rotational and the radial direction with respect to the lid portion 30b be hindered because the pins 30a in the holes 32d are inserted.
The outer peripheral surface of the damping element 32 is in sliding contact with the inner peripheral surface 32b and the clamping shell 22 , Two C-shaped ring springs 33 are in a radially inwardly compressed state on the inner peripheral surface of the annular Dämpfelements 32 attached so that the damping element 32 against the inner peripheral surface of the clamping shell 22 is biased and pressed with the substantially uniform and constant pressure. As a result, during the pivoting movement of the clamping arm 30 a damping force as a frictional force between the damping element 32 and the clamping shell 22 generated. Of course, a biasing force of the ring springs 33 suitably selected in accordance with the required damping force.
The 5 and 6 show an external appearance of the clamping arm 30 with the lid section 30b and the disc mounting portion 30c which is integrally made of a suitable metal material. The lid section 30b has a lead 30d projecting from its side surface, and the projection 30d is at the end 52 the torsion spring 50 engaged when the tension arm 30 in the tensioner 10 is installed. The lid section 30b also has a cylindrical pivot pin bearing 30e that protrudes from its middle. The sleeve 31 is in the warehouse 30e added. Next is the lid section 30b with a guide groove 30f is formed, which extends along its outer portion on one side, the pane mounting portion 30c the lid section 30b is opposite. The projections or circular rod-like pins 30a coming from the lid section 30b protrude, lie the guide grooves 30f opposite and are in the axial direction of the clamping shell 22 aligned when the tension arm 30 in the tensioner 10 is installed. The window mounting section 30c has a disc bolt bearing 30g , which is formed at its center, and the disc bolt 41 for the clamping disc 40 is in the disc bolt bearing 30g screwed.
The 7 and 8th show an external appearance of the damping element 32 , Although the damping element 32 has an annular shape, that of the opening of the clamping shell 22 follows, as can be seen from these drawings, is the damping element 32 split so that a gap 32b is formed therein. The gap 32b contributes to a thermal deformation of the damping element 32 to absorb and also serves as a drainage channel for drainage, which is in the clamping shell 22 penetrates.
The damping element 32 has an insert section 32c which is integrally formed along its inner circumference on a side which is the gap 32b of the damping element 32 opposite. Like from the 7 is obvious, the insertion section extends 32c from the side of the annular body as such of the damping element 32 on the lid section 30b of the tensioning arm 30 is applied when the damping element 32 in the tensioner 10 is installed. How out 8th Obviously, the above-mentioned annular holes are 32d in the insertion section 32c formed and are at the same positions in the radial direction offset from the center of the damping element 32 arranged. The center axes of the annular holes 32d are parallel to the pivot pin 23 when the damping element 32 in the tensioner 10 is installed. Furthermore, there is a groove 32e in the insertion section 32c formed and contributes to a deformation of the insertion portion 32c to absorb.
The damping element 32 has a pair of sector-shaped elements 32f , which are integrally formed on its inner peripheral surface, and the sector-shaped elements 32f are on the sides of the gap 32b arranged. The sector-shaped elements 32f are sliding in the guide groove 30f taken in the lid section 30b of the tensioning arm 30 is formed, and that when the damping element 32 in the tensioner 10 is installed. The damping element 32 has another pair of sector-shaped elements 32g that are integral to its inner peripheral surface are formed, and the sector-shaped elements 32g serve as a ring holder for the ring springs 33 , The sector-shaped elements 32g are under the ring springs 33 arranged to prevent the ring springs 33 Move down ( 3 ).
9 shows a type of C-shaped ring spring 33 which has a uniform width, and 10 shows a different type of C-shaped ring spring 33 having a maximum width at its middle position and a varying width gradually decreasing from the middle position to the ends. Each of the two types can be in the damping element 32 to be built in. Of course, still another type of ring spring in the tensioner 10 used, although it is not shown.
The 11 and 12 show another embodiment of the damping element 32 , which is composed of elements similar to those of the 7 and 8th are denoted by the same reference numerals. In this embodiment, the splitting gap becomes 32b of the damping element 32 by a clamping element 32h bridged, which extends from one of the opposite outer end edges, the gap 32b define, and comes into sliding engagement with the other end edge.
If that is in the 7 and 8th shown damping element 32 in the tensioner 10 is built in, as in 3 is shown forms the splitting gap 32b of the damping element 32 a narrow opening at a location along the outer periphery of the lid portion 30b of the tensioning arm 30 , Then fragments, fragments or the like can enter the interior of the clamping shell 22 through the narrow opening or the division gap 32b of the damping element 32 penetration. By contrast, in the arrangement of the damping element 32 as they are in the 11 and 12 is shown, no opening at a position along the outer periphery of the lid portion 30b of the tensioning arm 30 formed because there is the clamping element 32h is available. This is the penetration of fractions, fragments or the like in the clamping shell 22 through the gap 32b prevented.
When the belt tensioner 10 is installed in the belt drive system, which in 1 is shown, the tension arm 30 in the direction of rotation by the elastic force of the torsion spring 50 so pretensioned that the drive belt 7 through the clamping disc 40 is tense, which is engaged with this. During operation of the belt drive system, the tension arm is subject 30 inevitable of vibration or vibration through the drive belt 7 but the vibration or vibration of the tension arm 30 can be effectively damped due to the damping force, which certainly by the annular spring 33 between the inner peripheral surface of the clamping shell 22 and the outer peripheral surface of the damping element 32 is produced.
When the belt tensioner 10 is needed, wears the outer peripheral surface 32a of the damping element 32 bit by bit. Nevertheless, according to the present invention, no gap is created between the damping member 32 and the lid portion 30b of the tensioning arm 30 because the damping element 32 due to the effect of the ring spring 33 spreads exactly by the amount of wear, and because the holes 32d of the damping element 32 over the cones 30a are taken care of. Accordingly, noise is prevented by any gap at the time of pivoting the tensioner arm 30 could arise.
Because the insertion section 32c from the annular body of the damping element 32 extends, that is, because the insertion section 32c over the outer peripheral surface 32a of the damping element 32 is formed, in sliding contact with the inner peripheral surface of the clamping shell 22 is the insertion section 32c resistant to effects of relative movement of the damping element 32 due to the wear of its outer peripheral surface.
There continue the variety of cones 30a of the tensioning arm 30 in the circular holes 32d are inserted, which is distributed on the damping element 32 through the torsion spring 50 while swinging the tensioner arm 30 applied force on a variety of insertion points (pins 30a ), which can prevent premature damage and premature deterioration of the damping element.
Each of the above-mentioned belt tensioners was tested in a durability tester as in 13 is shown. In this durability tester, reference designates 10 ' a belt tensioner to be tested. The belt tensioner 10 ' includes a fixed element 20 ' and a clamping washer 40 ' around an axis of a pivot shaft 23 ' is pivotable. The disc 40 ' is rotationally driven by an eccentric disc EP by means of a drive belt DB. The durability test was carried out under the following conditions:

(a) the sliding speed at the sliding surfaces of the damping element and the clamping shell: 0,21 m / s
(b) the sliding pressure exerted by the damping element on the clamping shell: 49 N / cm ²
(c) the amount of relative sliding movement between the damping element and the clamping shell: 4.1 mm

The sliding speed 0.21 m / s depends on a running speed of the Antriebriemens DB from; the sliding pressure depends on a modulus of elasticity of a torsion spring provided in the damping member concerned; and the amount of the relative sliding movement depends on an eccentricity of the eccentric disk EP.
Each of the durability tests was performed over a period of 300 hours, the 14 and 15 show the results of the durability tests. In the graphic of the 14 For example, S1 and S2 represent the belt tensioner having the cushioning member made of polyacetal (POM), and B1 and B2 represent the belt tensioner having the cushioning member made of polyhexamethylene terephthalamide (APA). In the belt tensioner with the POM cushioning member, cracks occurred in the inserting portion after running for 150 to 200 hours 32c of the damping element, in which the circular holes 32 are formed. In contrast, the APA damper belt tensioner did not crack until a running time of 300 hours elapsed. According to the graph of 15 For example, the APA damper has a relatively small amount of wear compared to that of the POM damper.

Claims

Belt tensioner with the following components: a clamping shell ( 22 ), which has an opening; a tensioning arm ( 30 ), which has a lid section ( 30b ), which is formed at its one end, wherein the lid portion ( 30b ) rotatable with the clamping shell ( 22 ) and extends so that it the opening of the clamping shell ( 22 ) closes; an elastic biasing device ( 50 ), which are in the clamping shell ( 22 ) is provided and between the clamping shell ( 22 ) and the tensioning arm ( 30 ) acts to tighten the tension arm ( 30 ) in one of the directions of rotation; and a damping element ( 32 ) fixed to the lid portion ( 30b ) of the tensioning arm ( 30 ) is fixed, so that an outer circumferential surface of the damping element ( 32 ) in sliding contact with an inner circumferential surface of the clamping shell ( 22 ), characterized in that the lid portion ( 30b ) of the tensioning arm ( 30 ) at least with two rod-shaped peg-like elements ( 30a ) is provided, which from there parallel to a pivot axis of the lid portion ( 30b ) of the tensioning arm ( 30 ), and wherein the rod-shaped peg-like elements ( 30a ) in holes ( 32d ) inserted in the damping element ( 32 ), whereby the damping element ( 32 ) on a movement in both the rotational and radial direction with respect to the lid portion ( 30b ) of the tensioning arm ( 30 ) is hindered.
Belt tensioner according to claim 1, characterized in that the rod-shaped pin-like elements ( 30a ) and the holes ( 32d ) are arranged in positions which are from a center of the damping element ( 32 ) are offset.
Belt tensioner according to claim 2, characterized in that the rod-shaped pin-like elements ( 30a ) and the holes ( 32d ) at equal intervals in the radial direction from the center of the damping element ( 32 ) are arranged.
Belt tensioner according to claim 1, characterized in that the damping element ( 32 ) an insert section ( 32c ) formed integrally therewith, said holes ( 32d ) in the inserting section ( 32c ) are formed.
Belt tensioner according to claim 4, characterized in that the damping element ( 32 ) has an annular body and the insertion portion ( 32c ) of the damping element ( 32 ) extends integrally from one side of the ring body.
Belt tensioner according to claim 5, characterized in that the insertion section ( 32c ) of the damping element ( 32 ) along an inner periphery of the damping element ( 32 ) is arranged.
Belt tensioner according to claim 6, characterized in that the annular body is divided so that therein a gap ( 32b ) is formed and the insertion section ( 32c ) of the damping element ( 32 ) is arranged in the diameter direction on the side leading to the gap ( 32b ) of the annular body is opposite.
Belt tensioner according to claim 1, characterized by at least one annular spring element ( 33 ), which in the damping element ( 32 ) is arranged so that an outer circumferential surface of the damping element ( 32 ) elastically against an inner circumferential surface of the clamping shell ( 22 ) is biased.
Belt tensioner according to claim 8, characterized in that the annular spring ( 33 ) is designed as a C-shaped annular spring.
Belt tensioner according to claim 1, characterized in that the holes ( 32d ) of the damping element ( 32 ) via the rod-shaped peg-like elements ( 30a ) are taken care of substantially without formation of a gap.
Belt tensioner according to claim 10, characterized in that the holes ( 32d ) of the damping element ( 32 ) and the rod-shaped peg-like elements ( 30a ) has a circular cross section ha ben.