Source: https://patents.google.com/patent/FR2672362A1/en
Timestamp: 2020-05-31 17:30:32
Document Index: 530987836

Matched Legal Cases: ['art 41', 'art 40', 'art 41', 'art 40', 'art 40', 'art 41', 'art 41']

FR2672362A1 - Self-tensioner. - Google Patents
Self-tensioner. Download PDF
FR2672362A1
FR2672362A1 FR9200935A FR9200935A FR2672362A1 FR 2672362 A1 FR2672362 A1 FR 2672362A1 FR 9200935 A FR9200935 A FR 9200935A FR 9200935 A FR9200935 A FR 9200935A FR 2672362 A1 FR2672362 A1 FR 2672362A1
FR9200935A
FR2672362B1 (en
Nakagawa Kazufumi
1991-01-31 Priority to JP1991002773U priority Critical patent/JP2560655Y2/en
1992-01-29 Application filed by NTN Corp, NTN Toyo Bearing Co Ltd filed Critical NTN Corp
1992-08-07 Publication of FR2672362A1 publication Critical patent/FR2672362A1/en
1994-02-11 Publication of FR2672362B1 publication Critical patent/FR2672362B1/en
<P> The belt self-tensioner comprises a pulley support shaft 3 fixed to a base, an eccentric ring (4) rotatably mounted on the pulley support shaft (3) and the center of its outer peripheral surface is offset from the center of the pulley support shaft, a pulley (8) rotatably supported around the eccentric ring by means of a roller bearing (7), a spring (10) which acts on the eccentric ring for pressing the pulley against the belt (11), a damper (20) which communicates a resistance to rotation to the eccentric ring preventing the pivoting movement of the pulley, the resistance to rotation communicated to the ring eccentric by the damper is caused on the side of the roller bearing which is opposite the base. </P>
SELF-TENSIONER
The present invention relates to a self-tensioning device which maintains constant tension of a belt such as a camshaft drive belt of a
As shown in Figures 6 and 7, a belt transmission device for driving the camshafts comprises a pulley 51 mounted on a crankshaft 50, pulleys 53 mounted on the camshafts 52 and an endless belt of
synchronization 54 arranged around the pulleys 51 and 53.
An autotensioner X is provided on the side towards which the belt tends to loosen so as to maintain
constant the belt tension 54.
Such a type of autotensioner is described in
publication of the Japanese utility model not examined 1-
171 952, which includes a shock absorber mounted on a pulley support which rotatably supports a pulley so as to provide rotational resistance to the pulley support. The self-tensioning device fitted with a shock absorber can prevent the pulley from moving excessively towards the release side, as well as the pulley support by imposing resistance on the pulley support.
used to reduce the vibration of the belt.
In this conventional autotensioner, the shock absorber is arranged between the engine block and a roller bearing which is provided between the pulley support and the pulley. Therefore the height between the engine block and the center of the pulley is rather large, this which causes the synchronization belt 54 shown in FIG. 7 to be arranged apart from the engine block 55 This reduces the
stiffness of the crankshaft 50 and of the camshafts 52.
An object of the present invention is to reduce the height between a base such as an engine block and the
center of a self-tensioning pulley.
According to the present invention, the belt self-tensioner comprises a pulley support shaft fixed to a base, an eccentric ring rotatably supported on the pulley support shaft in an offset position, a pulley for the belt rotatably mounted on the eccentric ring by means of a roller bearing, actuating means for causing the eccentric ring to press the pulley against the belt, and a damper for imparting resistance to rotation to the eccentric ring and preventing movement pivoting pulley, characterized in that the resistance to rotation is communicated to the eccentric ring by the damper
on the side of the roller bearing opposite the base.
Because the shock absorber causes resistance to rotation with the eccentric ring on the side of the roller bearing opposite the base, the pulley can be mounted closer to the base Thus the height between the base and the center of the pulley can be reduced As a result, the stiffness of the crankshaft and camshafts
Other characteristics and objects of the present invention will appear more clearly on
reading of the following description and with reference to
attached drawings in which: Figure 1 is a front view in vertical section of a first embodiment of the self-tensioning device according to the present invention; Figure 2 is a side view of the autotensioner;
Figure 3 is a sectional view along III-
III of Figure 2; Figure 4 is a sectional view along line IV-IV of Figure 2; Figure 5 is a front view in vertical section of a second embodiment; Figure 6 is a belt drive device which includes a self-tensioning device; and Figure 7 is a side view of the device
Figures 1 to 4 show the first embodiment. In these figures a bolt 2 is screwed into an engine block 1 and constitutes a base. A cylindrical shaft 3 for pulley support is adjusted around the bolt 2 and it is fixedly mounted on the engine block
1 by tightening the bolt 2.
An eccentric ring 4 is provided around the pulley support shaft 3 and it includes a passage for receiving the pulley support shaft 3 so as to be arranged offset from the center of its outer periphery A bearing 6 is interposed between
the passage 5 and the pulley support shaft 3.
Around the eccentric ring 4, a pulley 8
is rotatably mounted by means of a roller bearing 7.
A tension arm 9 is fixed to one end of the eccentric ring 4, opposite the engine block 1 A tension adjustment spring 10 is coupled to the end of the arm
The tension adjustment spring 10 causes a resistance to rotation on the eccentric ring 4 in the direction of the arrow in FIG. 2, which
causes the pulley 8 to be pressed against the belt 11.
The resistance to rotation is applied to the eccentric ring by a damper 20 This resistance to rotation serves to reduce the vibration of the belt 11, thus preventing the pulley 8 from pivoting excessively relative to the support support shaft. pulley 3 in a direction such that the belt 11 is released. As shown in FIG. 3, the eccentric ring 4 is constituted by a first cylinder chamber 21 comprising an opening at the end of the ring 4 which is remote from the engine block 1 A plunger 22 mounted sliding in the first chamber cylinder 21 comprises at its rear end an axial passage 23 in which a piston 24 and a spring 25 are mounted The spring 25 serves to press the piston 24 against the bottom of the first cylinder chamber 21 and forces the plunger
22 to go outside.
The plunger 22 is provided at its end with a spherical protrusion 26 A sliding member 28 is in sliding contact with the outer spherical surface of the spherical protrusion 26 and it is pressed by the spring against an inclined cam surface 30 of a cam 29
mounted at the end of the pulley support shaft 3.
A pressure chamber 31 is provided in the
plunger 22 by the piston 24 in which it is mounted.
It communicates with a reservoir chamber 32 formed in the piston 24 by a passage 33 formed in the piston 24 A retaining valve or valve 34 is provided at the end of the passage 33 to open and close the passage. The eccentric ring 4 comprises a second cylinder chamber 35 in which are mounted a piston 36 and a spring 37 A rear piston chamber 38 defined by the piston 36 communicates with the reservoir chamber 32 to absorb any change in the volume of the oil hydraulically enclosed in the pressure chamber 31, the reservoir chamber 32 and the rear chamber of
piston 38 when piston 36 moves.
Due to the contact resistance between the inclined cam surface 30 and the sliding member 28, a resistance to rotation is applied to the eccentric ring 4 This resistance to rotation serves to reduce the vibration of the belt there and prevents the pulley 8 to pivot excessively relative to the pulley shaft 3 in a direction such that the
belt slackens.
With such a damper 20, when the belt is released and the eccentric ring 4 is rotated by the force of the tension adjustment spring 10, the pulley 8 pivots relative to the pulley support shaft 3 in a direction such that the tensioned belt 8 stretches and the sliding member 28 slides along the inclined cam surface 3 towards its lower part At the same time, the plunger 22 is moved by the force of the spring 25 and the passage 33 is opened by the valve 34 allowing the hydraulic oil from the reservoir chamber 32 to flow into the pressure chamber 31 Consequently, the plunger 22 can move gently outwards, so that the pulley 8 can move quickly in such a direction
as the stretched belt is stretched or elongated.
Furthermore, when the tension of the belt 11 increases and the pulley 8 is pushed by the belt in a direction which allows the slackening of the belt, the eccentric ring 4 rotates and the sliding member 28 slides along the surface of cam inclined towards its upper part At the same time, the plunger 22 is pushed towards the first cylinder chamber 21 and the passage 33 is closed by the valve 34, so that the hydraulic oil in the pressure chamber 31 is subjected to a high pressure and leaks through an interval of the sliding surface between the plunger 22 and the piston 24 in the reservoir chamber
Thus the plunger 22 moves backwards at low speed. The pulley 8, consequently, pivots gently in a direction such that it releases the
belt 11.
According to the present invention, the resistance to rotation is communicated to the eccentric ring 4 by the damper 20 at a location which is further from the engine block 1 than from the roller bearing 7. Thus, the pulley 8 can be mounted near the block. engine 1, this reduces the height h between the engine block and the center of
the pulley 8.
FIG. 5 represents a second mode of
realization of the autotensioner according to the present invention.
In this embodiment, a pulley support shaft 3 a which is fixed to the engine block 1 by tightening the bolt 2, has an end portion 40 of large diameter. An eccentric ring 4 a is rotatably mounted on a shaft. pulley support 3 a and comprises a cylindrical part 41 disposed around the large diemeter part 40 A damper 20 a is provided between the
cylindrical part 41 and the large diameter part 40.
A gap 42 is made between the large diameter part 40 and the cylindrical part 41 and it is
closed by a pair of sealing members 43.
The sealed gap 42 is filled with a viscous fluid.
The viscous fluid resistance is used as
resistance to rotation of the eccentric ring 4 a.
In this second embodiment, the resistance to rotation is also communicated to the eccentric ring 4 a at a point which is more distant from the engine block 1 than from the bearing 7 Thus the pulley 8 can be mounted near the engine block 1 of so that the height H between the engine block 1 and the center of the pulley 8 can
In this second embodiment, a tension arm 9 a comprises one of its ends which is fixed to the cylindrical part 41 of the eccentric ring 4 a and its other end coupled to the tension adjustment ring 10 to communicate a rotational force at
the eccentric ring 4 a.
1 Belt tensioner comprising a pulley support shaft (3.3 a) fixed to a base, an eccentric ring (4.4 a) rotatably mounted on said pulley shaft, offset, a pulley (8) for said belt, rotatably mounted on said eccentric ring by means of a roller bearing (7), actuating means for causing said eccentric ring to press said pulley against the belt (11) and a shock absorber (20,20 a ) to communicate a resistance to rotation to said eccentric ring to prevent the pivoting movement of said pulley, characterized in that the resistance to rotation is communicated to said eccentric ring (4, 4 a) by said damping (20.20 a) on the side of the roller bearing which is opposite said base 2 A belt tensioner according to claim 1, which further comprises a tension arm (9,9 a) having one of its ends which is fixed to the eccentric ring on the rolling bearing side water which is distant from said base, said actuating means being coupled to said tension arm to communicate a force
of rotation to said eccentric ring (4.4 a).
FR9200935A 1991-01-31 1992-01-29 Self-tensioner. Expired - Fee Related FR2672362B1 (en)
JP1991002773U JP2560655Y2 (en) 1991-01-31 1991-01-31 Auto tensioner
FR2672362A1 true FR2672362A1 (en) 1992-08-07
FR2672362B1 FR2672362B1 (en) 1994-02-11
ID=11538660
FR9200935A Expired - Fee Related FR2672362B1 (en) 1991-01-31 1992-01-29 Self-tensioner.
US (1) US5186689A (en)
JP (1) JP2560655Y2 (en)
KR (1) KR960009742Y1 (en)
DE (1) DE4202166C2 (en)
FR (1) FR2672362B1 (en)
GB (1) GB2252388B (en)
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1991-01-31 JP JP1991002773U patent/JP2560655Y2/en not_active Expired - Fee Related
1992-01-27 DE DE19924202166 patent/DE4202166C2/en not_active Expired - Fee Related
1992-01-29 KR KR92001312U patent/KR960009742Y1/en not_active IP Right Cessation
1992-01-29 FR FR9200935A patent/FR2672362B1/en not_active Expired - Fee Related
1992-01-30 US US07/828,361 patent/US5186689A/en not_active Expired - Lifetime
1992-01-31 GB GB9202138A patent/GB2252388B/en not_active Expired - Fee Related
GB2252388A (en) 1992-08-05
DE4202166C2 (en) 2000-06-29
GB9202138D0 (en) 1992-03-18
US5186689A (en) 1993-02-16
JP2560655Y2 (en) 1998-01-26
DE4202166A1 (en) 1992-08-06
FR2672362B1 (en) 1994-02-11
JPH0496649U (en) 1992-08-21
GB2252388B (en) 1995-01-18
KR960009742Y1 (en) 1996-11-06
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