WO2016009524A1

WO2016009524A1 - Friction fastening element and dry clutch equipped with such friction fastening element

Info

Publication number: WO2016009524A1
Application number: PCT/JP2014/069012
Authority: WO
Inventors: 政治寺内; 将史波田野; 竜也大曽根; 隆弘猿渡
Original assignee: 日産自動車株式会社
Priority date: 2014-07-17
Filing date: 2014-07-17
Publication date: 2016-01-21

Abstract

The present invention is a friction fastening element (F) that comprises: a friction member (91b) that has a thermoplastic resin as a principal constituent; and a partner member (93) that is made of cold-rolled high-tensile steel. The friction member (91b) comprises glass fibers and copper wires that have been impregnated with the thermoplastic resin as a fiber base material. Moreover, the copper wires account for 0.6-3.3% by volume of the friction member (91b).

Description

Friction fastening element and dry clutch provided with the friction fastening element

The present invention relates to a friction engagement element and a dry clutch provided with the friction engagement element.

装置 Devices that transmit power (torque) by fastening frictional engagement elements are widely used in various fields such as transportation equipment such as automobiles and industrial machinery. Devices used in the automotive field include, for example, a travel mode transition clutch used in a driving force transmission device of a hybrid electric vehicle, a vehicle start clutch using only one of an engine or an electric motor as a travel drive source, a vehicle There are other braking devices. Patent document 1 is disclosing the friction material used for the brake pad of a motor vehicle.

Japanese Patent Laid-Open No. 62-142630

By the way, in a device that transmits power by fastening frictional engagement elements, power transmission may become unstable in a specific rotational speed and torque region, and a phenomenon may occur in which the transmission torque vibrates greatly. When the vibration phenomenon of the transmission torque occurs, the life of the friction material is deteriorated or abnormal noise is generated from a member on the power transmission path.

The present invention has been made to solve the above-described problems, and an object thereof is to improve the stability of the transmission torque of the frictional engagement element.

One aspect of the present invention is a friction engagement element including a friction material mainly composed of a thermosetting resin and a counterpart material made of cold-rolled high-tensile steel. The friction material has glass fibers and copper wires impregnated with a thermosetting resin as a fiber base material. Moreover, the friction material contains 0.6 volume% or more and 3.3 volume% or less of copper wire.

The friction material has excellent rigidity because the fiber base material is impregnated with a thermosetting resin and the structural integrity of the reinforcing fiber and the resin is improved. In particular, this fiber base material contains copper wire having a high thermal conductivity of not less than 0.6% by volume and not more than 3.3% by volume, and can efficiently dissipate frictional heat, so that it has high rigidity even during operation. Can be maintained. On the other hand, since the counterpart material that slides with the friction material is made of cold-rolled high-tensile steel, even when the temperature rises due to frictional heat, a decrease in hardness is suppressed. That is, according to the above frictional engagement element, the friction material having improved rigidity and the driven plate having maintained hardness slide, so that the amplitude is suppressed even when the transmission torque is vibrated at the time of engagement. be able to. Thus, according to the present invention, the stability of the transmission torque of the frictional engagement element can be improved.

FIG. 1 is a cross-sectional view showing a main configuration of a hybrid driving force transmission device to which a frictional engagement element according to an embodiment of the present invention is applied. FIG. 2 is a graph showing the wear resistance of the frictional engagement element of FIG. FIG. 3 is a graph showing torque transmission characteristics of the frictional engagement element of FIG. FIG. 4 is a graph showing the relationship between the volume ratio of the copper wire and the amplitude of the transmission torque in the frictional engagement element of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

An example in which the frictional engagement element F according to the embodiment of the present invention is applied to the hybrid driving force transmission device S will be described with reference to FIG.

As shown in FIG. 1, the hybrid driving force transmission device S includes a clutch hub shaft 1 connected to an output shaft of an engine (not shown) via a damper, and is arranged coaxially with the clutch hub shaft 1. A clutch cover shaft 3 connected to an input shaft (not shown), a clutch hub 5 connected to the clutch hub shaft 1, a clutch cover 7 connected to the clutch cover shaft 3, a clutch hub 5 and a clutch cover 7 Are provided with a normally open dry multi-plate clutch 9, a slave cylinder 11 for controlling the engagement / release of the clutch 9, and a motor generator 13.

The clutch 9 includes drive plates 91 and driven plates (counter members) 93 that are alternately arranged along the direction of the rotation axis X of the clutch 9. Each drive plate 91 is spline fitted to the clutch hub 5 so as to be movable in the axial direction, and each driven plate 93 is spline fitted to the clutch cover 7 so as to be movable in the axial direction.

The slave cylinder 11 is a hydraulic actuator and includes a rod 11a that can move in the direction of the rotation axis X. The slave cylinder 11 applies a pressing force in the direction of the rotation axis X to the clutch 9 through the rod 11a and the pressing plate 15 elastically supported by the clutch cover 7. A return spring 17 is interposed between the flange portion 11 b provided on the proximal end side of the rod 11 a and the clutch cover 7.

When the clutch 9 is engaged, the hydraulic pressure produced by the transmission is supplied to the slave cylinder 11, and the rod 11a is moved against the urging force of the return spring 17 to the clutch 9 side (right direction in FIG. 1). As a result, a fastening force, which is the difference between the oil pressure and the urging force, is transmitted to the clutch 9 via the rod 11a and the pressing plate 15, and the drive plate 91 and the driven plate 93 are pressed against each other, and the clutch 9 is fastened. Is done.

When releasing the clutch 9, the hydraulic pressure supplied to the slave cylinder 11 is released, and the rod 11a is moved away from the clutch 9 (leftward in FIG. 1) by the urging force of the return spring 17. As a result, the fastening force transmitted to the clutch 9 via the rod 11a and the pressing plate 15 is released, and the clutch 9 is released.

The motor generator 13 is a synchronous AC motor, and includes a rotor support frame 13a formed integrally with the clutch cover 7, and a motor rotor 13b supported and fixed to the rotor support frame 13a and embedded with permanent magnets. Furthermore, the motor generator 13 has a motor stator 13d disposed outside the motor rotor 13b via the air gap 13c, and a stator coil 13e wound around the motor stator 13d.

When the clutch 9 is released, the hybrid driving force transmission device S is in an “electric vehicle traveling mode” in which the motor generator 13 and the input shaft of the transmission are connected via the clutch cover 7 and the clutch cover shaft 3. When the clutch 9 is engaged, a “hybrid vehicle travel mode” in which the motor generator 13 and the engine are coupled via the clutch hub 5 coupled to the clutch cover 7 via the clutch 9 and the clutch hub shaft 1. It becomes. That is, the clutch 9 interrupts or connects the driving force transmission from the engine, and changes the travel mode of the hybrid electric vehicle.

<Friction fastening element>
As shown in FIG. 1, the drive plate 91 includes a cushion plate 91a and a friction material 91b fixed to both surfaces of the cushion plate 91a. On the inner peripheral edge of the cushion plate 91a, an internal spline 91c that is spline-fitted to the external spline 5a provided on the outer peripheral surface of the clutch hub 5 is provided.

The driven plate 93 that slides on the friction material 91b is a circular plate made of high-tensile steel. As shown in FIG. 1, the outer peripheral edge of the driven plate 93 is provided with an external spline 93 a that is spline-fitted to an internal spline 7 a provided on the inner peripheral surface of the clutch cover 7. The surface of the driven plate 93 that faces the friction material 91b is a sliding surface that slides on the friction material 91b.

As shown in FIG. 1, a friction fastening element F is constituted by a friction material 91b and a driven plate 93 that slides with the friction material 91b.

<Friction material>
The friction material 91b is mainly composed of a phenol resin having a thermosetting resin as a main component and a volume ratio with respect to the entire friction material 91b of, for example, 70 to 90% by volume, and other fiber base materials and compounded rubber.

The fiber base material of the friction material 91b is composed of glass fiber and copper wire. The glass fiber and the copper wire are impregnated with a thermosetting resin, and the gap between the fibers of the glass fiber and the copper wire is filled with the thermosetting resin. The thermosetting resin impregnated into the fiber base material is preferably the same as the thermosetting resin that is the main component of the friction material 91b, but it is prepared to have a lower viscosity in consideration of the impregnation property into the fiber base material. Different materials may be used.

More specifically, the fiber base material of the friction material 91b is made of glass fiber yarn and copper wire twisted string. The copper wire is wound around a glass fiber yarn as a core material. The shape of the glass fiber is not limited to a yarn shape, and may be a roving shape, a ribbon shape, a string shape, or the like. The volume ratio of the glass fibers is not particularly limited, and can be set, for example, to 15 volume% or more and 20 volume% or less of the entire friction material 91b. A copper wire consists of copper or a copper alloy, The volume ratio is set to 0.6 volume% or more and 3.3 volume% or less of the friction material 91b whole.

The manufacturing method of the friction material 91b includes each process such as a fiber impregnation process, a rubber adhesion process, a molding and firing process, and a grinding / polishing process.

In the fiber impregnation step, using a known twisting machine, a copper wire is wound around the glass fiber yarn as a core material to form a glass fiber yarn and a copper wire twisted string. Then, the obtained twisted string is passed through a resin tank in which a liquid thermosetting resin is stored, and impregnated with the thermosetting resin.

In the rubber adhesion process, semi-solid compounded rubber is adhered to a twisted string impregnated with a thermosetting resin. The compounded rubber contains at least a rubber material and graphite as a friction modifier. Examples of the rubber material include acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), isoprene rubber (IR), butadiene rubber (BR), ethylene-propylene rubber (EPM), butyl rubber, chloroprene rubber (CR), Use of chlorosulfonated polyethylene (CSM), acrylic rubber (ACM), urethane rubber (U), silicone rubber (Si), fluoro rubber (FPM), polysulfide rubber (T), polyether rubber (POR), etc. it can. The compounded rubber may contain a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, etc. in addition to the rubber material and the friction modifier. As the vulcanizing agent, for example, sulfur, zinc oxide, magnesium oxide, peroxide, dinitrobenzene and the like are used. Examples of vulcanization accelerators include thiazole accelerators, polyamine accelerators, sulfenamide accelerators, dithiocarbamate accelerators, aldehyde amine accelerators, guanidine accelerators, thiourea accelerators, xanthate accelerators. An accelerator or the like can be used. As the vulcanization aid, for example, metal oxides such as zinc white, and fatty acids such as stearic acid and oleic acid can be used.

In the molding and firing process, the twisted string with the compounded rubber attached is formed into a perforated disk shape, for example, wound into a spiral shape or a thermoidal shape, and placed in a mold to apply pressure, Heating and pressure molding are performed under a predetermined temperature condition. Thereafter, heat treatment is applied in a predetermined atmosphere for a predetermined time.

In the grinding / polishing step, the molded body formed into a predetermined shape in the forming and firing steps is cut (cut) and polished to obtain a friction material 91b having a predetermined product shape.

<Driven plate (partner material)>
The driven plate 93 is made of cold-rolled high-tensile steel (tensile strength: 490 MPa or more). Specifically, an alloy obtained by hot rolling an alloy obtained by adding trace alloy elements of B, Cr, and Ti to a low carbon steel (carbon content: 0.02% or more and 0.30% or less) and cooling the pickled steel is cooled. Use hot-rolled steel. The metal structure of this steel material has a ferrite-pearlite structure and has high toughness.

The Vickers hardness (Hv) of the driven plate 93 is adjusted to 230 or more and 280 or less. Further, the surface roughness of the sliding surface of the driven plate 93 is defined within a predetermined range. Specifically, the arithmetic average roughness Ra defined in Japanese Industrial Standard (JIS-B-0601: 2001). Is set to 0.1 μm or more and 0.4 μm or less.

<Heat resistance>
In the friction material 91b according to the present embodiment, the copper wire having a high thermal conductivity is included in an amount of 0.6% by volume to 3.3% by volume of the entire friction material 91b, and the frictional heat is efficiently dispersed. Local overheating of the material 91b is prevented, and heat dissipation is improved. On the other hand, the driven plate 93 that slides with the friction material 91b is made of cold-rolled high-tensile steel and has a ferrite-pearlite structure in the metal structure, so even when the temperature rises due to frictional heat, Reduction is suppressed. Thus, according to the combination of this embodiment, the heat resistance of a friction fastening element can be improved.

<Abrasion resistance>
In the friction material 91b, since the fiber base material is impregnated with a thermosetting resin and the structural integrity of the reinforcing fiber and the thermosetting resin is improved, the friction material 91b has an excellent rigidity. Have In particular, as described above, the friction material 91b includes a copper wire having a high heat transfer coefficient at a relatively high ratio and has good heat dissipation, so that an increase in the friction surface temperature can be suppressed during operation. Since the wear amount of the friction material tends to increase as the friction surface temperature increases, the temperature suppression contributes to suppressing the wear resistance (suppressing the increase in the wear amount). Moreover, the driven plate 93 is made of cold-rolled high-strength steel as described above, and hardness reduction at the time of temperature rise is suppressed. As described above, according to the combination of the present embodiment, the wear resistance of the frictional engagement element can be improved, and the number of times of fastening / release until reaching the wear limit (endurance life) can be increased. If the frictional engagement element F is applied to, for example, an engine start clutch of a hybrid vehicle, the frequency of engagement / release of the clutch can be increased, which can contribute to an improvement in fuel consumption of the hybrid vehicle.

Further, the friction material 91b of the frictional engagement element F contains graphite as a friction modifier. Therefore, according to the frictional engagement element F, it becomes possible to contain a copper wire at a relatively high ratio while preventing the friction coefficient of the friction material 91b from becoming excessive, and further to improve the wear resistance of the frictional engagement element. Can be increased.

In order to evaluate the wear resistance of the frictional engagement element F, the frictional engagement element F and the frictional engagement element according to the comparative example are repeatedly engaged and released under a predetermined inertial load, and the change in the amount of wear is changed. Measured. The obtained results are shown in FIG. Here, the comparative example is a friction material in which the volume ratio of the copper wire is reduced to about one third of the estimated optimum value in the present embodiment to be described later, and a counterpart material made of a tempered material of high carbon steel. It is a combination. Moreover, in this comparative example, impregnation of the thermosetting resin with respect to the fiber base material of a friction material is not performed.

In the graph of FIG. 2, the horizontal axis represents the number of tests, that is, the number of engagement / release of the frictional engagement element, and the vertical axis represents the wear amount (mm). A solid line indicates a change in the amount of wear in the present embodiment, and a broken line indicates a change in the amount of wear in the comparative example. From FIG. 2, it was confirmed that the durability life (the number of times of fastening / opening until reaching the allowable limit value AL) of the present embodiment was extended by about 1.8 times the durability life of the comparative example.

<Transmission torque stability>
As described above, in the frictional engagement element F, the friction material 91b having improved rigidity and the driven plate 93 having maintained hardness slide, so that even when vibration is generated in the transmission torque at the time of engagement, the amplitude thereof is increased. Can be suppressed. Thus, according to the combination of this embodiment, the stability of the transmission torque of the frictional engagement element can be improved.

In the frictional engagement element F, as described above, the amplitude of the transmission torque is suppressed and energy loss during engagement is reduced, so that the frequency and amount of instantaneous heat generation in the frictional engagement element are reduced. That is, according to the frictional engagement element F, it is possible to increase the input / output rotational speed difference at the time of engagement while suppressing the generation of heat spots on the driven plate 93, and to exhibit excellent performance in high speed reliability. be able to.

In order to evaluate the torque transmission characteristics of the frictional engagement element F, a test was performed using a low-speed sliding friction test apparatus (manufactured by Automax Co., Ltd.) corresponding to the JASO (Japan Automobile Standardization Organization) M349-2012 test. In this test, the torque transmitted to the driven plate 93 when the friction material 91b is rotated while being pressed against the sliding surface of the driven plate 93 is measured. The pressing force was constant (for example, 490 N), and the number of rotations was increased from 0 rpm to 500 rpm for 5 seconds, held at 500 rpm for 2 seconds, and then decreased from 500 rpm to 0 rpm for 5 seconds. The obtained results are shown in FIG.

In the graph of FIG. 3, the horizontal axis indicates time, and the vertical axis indicates transmission torque (Nm). The solid line indicates the change in the transmission torque of the frictional engagement element F, and the broken line indicates the change in the transmission torque of the frictional engagement element according to the comparative example. From FIG. 3, it was confirmed that the maximum amplitude A1 of the transmission torque of this embodiment is suppressed to about 75 to 80% of the maximum amplitude A2 of the comparative example.

<Content of copper wire>
FIG. 4 is a graph showing the relationship between the volume ratio of the copper wire in the frictional engagement element F and the amplitude of the transmission torque. The horizontal axis of the graph represents the volume ratio (volume%) of the copper wire occupying the entire friction material 91b, and the vertical axis represents the amplitude (Nm) of the transmission torque. The volume ratio of the copper wire in the frictional engagement element F is preferably 0.6% by volume or more and 3.3% by volume or less. By setting the volume ratio of the copper wire to 0.6% by volume or more, it is possible to prevent the wear rate (cm ³ / J) of the friction material 91b from becoming excessive. Further, by controlling the volume ratio of the copper wire to 3.3% by volume or less, the controllability of the clutch capacity control is deteriorated due to the excessive friction coefficient of the friction material 91b when the frictional engagement element F is applied to the clutch. Can be avoided. Further, from the viewpoint of suppressing the amplitude of the transmission torque, as shown in FIG. 4, the volume ratio of the copper wire is preferably 1.0 volume% or more and 2.7 volume% or less, and more preferably 1 It is 0.5 volume% or more and 2.0 volume% or less, and an estimated optimal value is about 1.7 volume%.

As mentioned above, although embodiment of this invention was described, this embodiment is only the illustration described in order to make an understanding of this invention easy, and this invention is not limited to the said embodiment. The technical scope of the present invention is not limited to the specific technical matters disclosed in the above embodiment, but includes various modifications, changes, alternative techniques, and the like that can be easily derived therefrom.

In the above embodiment, the phenol resin is taken as an example of the thermosetting resin as the main component of the friction material 91b. However, the type of the thermosetting resin is not particularly limited, and various modified phenol resins, melamine resins, epoxy resins, An unsaturated polyester resin or the like may be used.

Moreover, in the said embodiment, although the example which applied the frictional engagement element concerning this invention to the dry multi-plate clutch 9 which has four driven plates was shown, the number of driven plates is not specifically limited, Three or less Or five or more sheets may be sufficient. The frictional engagement element according to the present invention can be applied to other types of clutches such as a single plate dry clutch.

Further, in the above embodiment, the example in which the frictional engagement element according to the present invention is applied to the normally open clutch 9 has been shown. However, the frictional engagement element according to the present invention can be applied to a normally closed clutch using a diaphragm spring or the like. Applicable.

In the above embodiment, an example in which the frictional engagement element according to the present invention is applied to the hybrid driving force transmission device S has been described. However, the frictional engagement element of the present invention uses only the engine as a travel drive source and uses the clutch as a starting clutch. The present invention can also be applied to the engine driving force transmission device. Further, the present invention can be applied to a motor driving force transmission device in which only a motor generator is used as a driving source and a clutch is used as a starting clutch. That is, the frictional engagement element according to the present invention can be applied to any device as long as it transmits a force by frictional engagement between a friction material and a counterpart material. For example, a brake system, a dual clutch system (DCT) It can also be suitably applied to an automatic manual transmission.

The friction engagement element and the dry clutch provided with the friction engagement element according to the present invention can be used in a device that transmits power (torque) by fastening the friction engagement element.

F Friction fastening element 9 Dry multi-plate clutch 91b Friction material 93 Driven plate (mating material)

Claims

A friction material mainly composed of a thermosetting resin;
A cold-rolled high-strength steel counterpart that is slidable on the friction material, and
The friction material has glass fibers and copper wires impregnated with a thermosetting resin as a fiber base material, and contains the copper wires in an amount of 0.6% by volume to 3.3% by volume. Friction fastening element.
The frictional engagement element according to claim 1, wherein the friction material further contains a friction modifier made of graphite.
The friction engagement element according to claim 1 or 2, wherein the friction material contains the copper wire in an amount of 1.5% by volume or more and 2.0% by volume or less.
A dry clutch comprising the frictional engagement element according to any one of claims 1 to 3.