JP3438034B2 - Friction damper - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction damper used for, for example, a transmission of an automobile. 2. Description of the Related Art A transmission for an automobile includes a gear which rotates constantly in association with a crankshaft of an engine, and a gear shaft which rotatably supports the gear.
In a low-speed rotation range such as pm, a so-called rattling sound of gear meshing and striking occurs. In order to suppress the generation of such rattle noise, a friction damper is used. FIGS. 6 and 7 show specific examples. FIG.
FIG. 7 is a sectional view showing a main part of the vehicle transmission, and FIG. 7 is a front view of the friction damper. In the figure, 31 is a gear, 32 is a gear shaft, 33 is a sleeve, 34 is a needle roller bearing, and 35 is a friction damper. The gear 31 is rotatably supported via a needle roller bearing 34 on a sleeve 33 externally fitted and fixed to the outer periphery of a non-rotating gear shaft 32. A friction damper 35 is disposed on the side of the needle roller bearing 34 between itself and the outer peripheral surface. The friction damper 35 is composed of a cylindrical metal core 36 and an elastic lip 37 made of rubber or the like which is attached to the outer periphery of the metal core 36 in a cantilever manner. The cored bar 36 is externally fitted and fixed to the non-rotating sleeve 33 and the elastic lip 3
7 is radially abutted against the inner peripheral surface of the gear 31 with a required repulsive elastic force.
By giving an appropriate amount of friction to gear 1, gear 3
This eliminates the backlash of 1 and suppresses the generation of rattle noise. Further, semicircular notches 38 are provided at several places (four places in the figure) of the outer periphery of the elastic lip 37. The notch 38 is provided to allow the lubricating oil to flow on both sides of the friction damper 35 in the axial direction.
The dimensions are appropriately set according to the amount of lubricating oil flow required by the automobile manufacturer. [0007] Generally, the friction damper 35 has a performance of suppressing the generation of rattle noise mainly in a low-speed rotation range and suppressing an increase in torque in a high-speed rotation range. Is required. That is, it is desirable to increase the frictional resistance to the gear 31 in the low-speed rotation range, and to decrease the frictional resistance in the high-speed rotation range.
The friction damper 35 must be designed in consideration of these. Although the conventional friction damper 35 as described above has a level of performance without any problem at present, further suppression of rattle noise is required in recent years. There is room for improvement, such as difficulty. In order to improve the performance level of the friction damper 35 as described above,
It is conceivable to increase the frictional resistance by increasing the contact area of the elastic lip 37 with the gear 31, or to increase the frictional resistance by increasing the contact pressure on the gear 31 by improving the bending rigidity of the elastic lip 37. However, none of the above measures can be taken for the following reasons. In other words, the size of the notch 38 provided in the elastic lip 37 cannot be simply changed because the size thereof is set according to the lubricating oil flow rate required by the automobile manufacturer. 37 gears 31
It is impossible to increase the contact area with respect to. The elastic lip 37 is discontinuous in the circumferential direction due to the shape of the notch 38 as the lubricating oil passage.
When the thickness of the elastic lip 37 is increased, the bending rigidity of the elastic lip 37 cannot be improved. Therefore, an object of the present invention is to improve the performance level of a friction damper. SUMMARY OF THE INVENTION The present invention is directed to a mandrel provided between two members rotatably disposed concentrically inside and outside in a radial direction and fitted on one member to the other. A friction damper in which an elastic lip that comes into contact with a member from a radial direction is attached, wherein a fluororesin is provided in a layer on a sliding surface of the elastic lip, and a circumferential number of a surface of the fluororesin is provided. said passage is inclined with respect to the axis to permit both axial sides of the lubricating oil circulation of resilient lip is provided at a location, the
The lubricating oil passage is a groove extending over the entire width in the axial direction. It is preferable that the above-mentioned elastic lip is set to be thick to improve bending rigidity . The above-mentioned fluororesin is hard, has excellent lubricity, and has a small coefficient of friction. First, since the elastic lip has a higher flexural rigidity because of its hardness, the friction can be set as large as possible by increasing the contact pressure of the elastic lip. On the other hand, when the lubricating property is excellent and the friction coefficient is small, the sliding condition becomes good. Therefore, even if the friction is set to be slightly large as described above, the rotational torque does not need to be significantly increased. As described above, by utilizing the favorable sliding conditions, the noise suppression effect in the low-speed rotation range is enhanced as much as possible, and the torque increase in the high-speed rotation range is suppressed as much as possible. That's how it works. Also, adjust the thickness of the elastic lip
From the root side to the free end side, not uniform as in the conventional case
The thickness of the lip is gradually increased toward
The rigidity is increased as much as possible. Therefore, as above
The friction damper with features is made of fluororesin
The rigid properties of the sheet and the body due to the increased thickness of the elastic lip
Flexibility of elastic lip is possible by synergistic with product increase
The contact pressure is increased to
Can increase the friction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described with reference to the embodiments shown in FIGS. FIGS. 1 to 5 relate to an embodiment of the present invention. FIG. 1 is a front view of a friction damper, and FIG. 2 is a sectional view taken along line (2)-(2) of FIG. 3 is a cross-sectional view taken along the line (3)-(3) in FIG. 1, FIG. 4 is a plan development view of an elastic lip of the friction damper, and FIG. 5 is a main part of an automobile transmission using the friction damper. FIG. In the figure, 1 is a gear, 2 is a gear shaft, 3 is a sleeve, 4 is a needle roller bearing, and 5 is a friction damper. The gear 1 is rotatably supported via a needle roller bearing 4 on a sleeve 3 externally fitted and fixed to the outer periphery of a non-rotating gear shaft 2. A friction damper 5 is arranged between the outer peripheral surface of the needle roller bearing 4 and the side thereof. The friction damper 5 has basically the same structure as that described in the conventional example, that is, a cylindrical cored bar 6.
And an elastic lip 7 made of a fluorine-based rubber or the like, which is attached to the outer periphery of the cored bar 6 in a cantilever manner. The cored bar 6 is externally fitted and fixed to the non-rotating sleeve 3, and the elastic lip 7 is radially abutted against the inner peripheral surface of the gear 1 with a required repulsive elastic force. By giving appropriate friction, the backlash of the gear 1 is eliminated, and the generation of rattle noise is suppressed. The characteristics of the friction damper 5 of the present invention are as follows.
A sheet 8 made of a fluororesin, for example, a tetrafluoroethylene resin, is adhered to the sliding contact surface of the elastic lip 7, and the elastic lip 7 is set to be thick in order to improve bending rigidity. . At several circumferential positions (eight in the figure) on the surface of the sheet 8, passage grooves 9 are provided on both sides of the elastic lip 7 in the axial direction as passages for allowing lubricating oil to flow. A plurality of oil grooves 10 for supplying lubricating oil to a sliding portion between the elastic lip 7 and the gear 1 are provided in a region between the passage grooves 9 (between the passage grooves 9 in the figure). Four) are formed. The former passage groove 9 extends over the entire axial width W of the elastic lip 7 and is inclined at a required angle θ with respect to the axis O, and the depth is set to be constant at the entire axial width W. The latter oil groove 10 is inclined with respect to the axis O similarly to the passage groove 9, opens at the base edge of the elastic lip 7, closes before the free end edge, and has a circumferential direction. Are connected to each of the adjacent oil grooves 10 and the passage grooves 9. By the way, although the size of each of the passage grooves 9 is smaller than that of the conventional notch, a required angle θ with respect to the axis O is set.
Due to the inclination, an action of taking in oil during rotation (pump action by a screw effect) occurs. Therefore,
The same lubricating oil flow rate as in the conventional example can be secured. Like this one
Due to the passage groove 9 having a reduced size per contact, the stress distribution when sliding on the gear 1 becomes substantially uniform on the circumference, and it is possible to contribute to the improvement of durability. In addition, by forming the lubricating oil passage from the conventional notch to the groove 9, the elastic lip 7 can be formed in a shape that is continuous in the circumferential direction.
This is advantageous in increasing the bending stiffness of the elastic lip 7, and moreover, always comes into contact with the gear 1 without interruption in the axial direction at the circumferential position where the groove 9 exists. On the other hand, friction can be given to the circumference substantially evenly, which is advantageous in suppressing generation of rattle noise. On the other hand, the thickness of the elastic lip 7 is not uniform as in the conventional example, but is gradually increased from the base side to the free end side, and has a substantially triangular cross section. . As shown in FIG. 5, the thickness of the elastic lip 7 is set so that the inner peripheral portion on the free end side of the elastic lip 7 does not interfere with the outer peripheral surface of the cored bar 6 to leave a slight gap in the used state. Is preferred. The elastic lip 7 is set so that the free end side thereof is located slightly inside the free end side of the metal core 6. In the friction damper 5 having such characteristics, the rigid property of the sheet 8 made of a fluororesin and
Since the flexural rigidity of the elastic lip 7 is increased as much as possible by the increase in the volume due to the increase in the thickness of the elastic lip 7 and the circumferential continuity of the elastic lip 7, the contact pressure is increased to increase the gear 1 The friction applied to can be increased. On the other hand, since the sheet 8 itself has excellent lubricity and a small coefficient of friction, the sliding condition of the elastic lip 7 with respect to the gear 1 during rotation can be improved. Therefore,
Generation of rattle noise in the low-speed rotation region can be suppressed as much as possible, and the rotation torque value in the high-speed rotation region can be kept within a required range. Therefore, the performance can be improved as compared with the conventional example. If the seat 8 is provided with the oil groove 10, the surrounding lubricating oil is taken in and the gear 1 and the elastic lip 7
Can be efficiently supplied to the sliding contact portion, and thereby, the lubrication conditions of the sliding contact portion can be made more favorable. This is advantageous in suppressing an increase in rotational torque in a high-speed rotation range. It should be noted that the present invention is not limited to only the above-described embodiment, and various applications and modifications are conceivable . Ma
And is arbitrary as long as the shape that can store captures the lubricating oil from the outside even the shape of the oil groove 10. According to the present invention, the performance level of the friction damper can be reduced, for example, the torque increase in the high-speed rotation range can be suppressed as much as possible while the noise generation suppression effect in the low-speed rotation range is enhanced. Be able to achieve up. In addition, durability can be enhanced by using a fluorine-based resin for the elastic lip. Therefore, when the friction damper of the present invention is used for an automobile transmission,
The generation of rattle noise in the low-speed rotation range can be effectively suppressed while reducing the engine power loss in the high-speed rotation range.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a friction damper according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line (2)-(2) of FIG. (3)-(3) arrow view of a line section [FIG. 4] FIG. 5 is an exploded plan view of an elastic lip of the friction damper of FIG. 1 [FIG. 5] FIG. FIG. 6 is a sectional view showing a main part of a conventional automobile transmission. FIG. 7 is a front view of the friction damper of FIG . 6 [Description of symbols] 1 gear 2 gear shaft 5 friction damper 6 core metal 7 elasticity Lip 8 Fluorine resin sheet 9 Passage groove

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Claims (1)

(57) Claims: 1. A core bar provided between two relatively rotatable members disposed concentrically inward and outward in the radial direction, and fitted to one member and to the other member. On the other hand, it is a friction damper in which an elastic lip that is abutted from the radial direction is applied, and a fluororesin is provided in a layer on a sliding contact surface of the elastic lip. The elastic lip is provided with a passage that is inclined with respect to the axis line that allows the flow of lubricating oil on both sides in the axial direction, and the lubricating oil passage extends over the entire width in the axial direction.
A friction damper characterized by a groove .