JP2008007109A - Presser member for accelerator operation resistance generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a presser member for an accelerator operation resistance generator with appropriate frictional force and sliding property, and having a sheet-like friction member with significantly improved resistance to abrasion and creep deformation. <P>SOLUTION: In the presser member for an accelerator operation resistance generator, friction resistance is given to a rotational shaft 4 directly or indirectly driving equipment for engine output control, to apply a resistance force to accelerator operation. The pressor member is constituted of the sheet-like friction member 2 and a metal plate-like member 3, and the friction member 2 is formed of fluororesin composition of fluororesin mixed with at least one compounding agent selected from whisker having Mohs hardness of 5 or less, carbon fiber, and hard resin powder. In the accelerator operation, the friction member 2 is relatively rotated with respect to the metal disc 5 normally or reversely to generate difference between a depression force and a returning force of an accelerator pedal, while being brought into press-contact with the metal disc 5 fixed to the rotational shaft 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pressing member for an accelerator operation resistance generator in a system for directly or indirectly driving an engine output control device, for example, an intake throttle valve, in accordance with a driver's accelerator operation amount.

The output control of an automobile engine is performed by opening and closing an intake throttle valve in a gasoline engine vehicle, and by rotating a plunger of an injection pump in a diesel engine vehicle.
In this output control, an output control device such as an accelerator pedal and an intake throttle valve or a plunger of an injection pump is connected by a wire cable, and the output control device is driven according to the driver's accelerator operation.
In recent years, the output control of a gasoline engine vehicle has been put to practical use as an actuator system in which an accelerator operation amount is converted into an electric signal to operate an actuator and an intake throttle valve is opened and closed by this actuator (Patent Document 1).
In the actuator system, the wire cable is extremely short as compared with the conventional one, so that the resistance by the wire cable is reduced, and the driver does not easily operate the accelerator. This difficulty in operating the accelerator may cause the driver to become tired more than necessary and may cause an accident.
This occurs even when the wire cable is shortened in a diesel engine vehicle.
For this reason, accelerator operation resistance generators that apply resistance to accelerator operation are known (Patent Documents 2 and 3).

For example, in Patent Document 3, a rotation shaft for driving an output control device of an engine indirectly or directly and an accelerator pedal are connected by a wire cable, and rotation of an output control device drive mechanism that rotates according to an accelerator operation amount. A device that applies a resistance force to the shaft, and the driver can operate the accelerator without feeling a sense of incongruity by constantly pressing a friction member made of a fluorine resin against a disc fixed to the rotating shaft using a spring member. Means are disclosed.
The reason why the friction member is used is to generate a difference between the accelerator pedal depression force and the return force. If this difference is small, when the driver depresses the accelerator pedal arbitrarily to keep the speed constant, the pedal operates even with a slight change in the depressing force that is not conscious, so that the pedal operation becomes difficult. If the difference is large, pedal operation becomes easy when the driver arbitrarily depresses the accelerator pedal to keep the speed constant, but uncomfortable pedal operation occurs when the speed is increased or decreased. This is because the pedal feels heavier when depressing or it is difficult to return when returning.
Japanese Utility Model Publication No.59-41708 JP-A-9-280076 JP-A-9-236030

However, the friction member formed of a fluorine-based resin has an appropriate frictional force and slidability, but has a problem that it is inferior in creep resistance and self-abrasion required for the friction member of the accelerator operation resistance generator. is there. That is, the fluororesin used for the conventional friction member has a large creep deformation and a large amount of self-wear.
As a result, the accelerator feeling changes due to the variation of the pressing load of the friction member due to creep deformation or self-wear. Furthermore, there is a problem that the rotational chatter of the friction member and the accelerator return deteriorate.

  The present invention has been made in order to cope with such a problem, and has a sheet-like friction member that has both appropriate frictional force and sliding property, and further greatly improved wear resistance and creep deformation resistance. Another object of the present invention is to provide a pressing member for an accelerator operating resistance generator.

  The pressing member for the accelerator operation resistance generator of the present invention is a pressing member that applies a frictional resistance to a rotating shaft that directly or indirectly drives an engine output control device and applies a resistance force to an accelerator operation, The pressing member is composed of a sheet-like friction member and a metal plate-like member, and the friction member is at least one compounding agent selected from fluororesin, whisker having a Mohs hardness of 5 or less, carbon fiber, and hard resin powder. In the accelerator operation, the friction member is pressed against the metal mating member fixed to the rotating shaft and is relative to the metal mating member in the forward and reverse directions. By rotating, a difference is generated between the accelerator pedal depression force and the return force.

The pressing member is characterized in that a sheet-like friction member and a metal plate-like member are bonded to each other.
In addition, a protrusion is formed on the outer diameter of the metal plate-like member of the pressing member, and it is impossible to rotate by fitting into a recess in the housing.

The fluororesin is at least one resin selected from a tetrafluoroethylene resin (hereinafter abbreviated as PTFE) and a modified tetrafluoroethylene resin (hereinafter abbreviated as modified PTFE).
The whisker is a single crystal having an aspect ratio of 10 or more.
Further, the hard resin powder is a polyimide resin powder or a polyamideimide resin powder, and is characterized by blending 5 to 25 parts by volume with respect to 100 parts by volume of the fluororesin.

  When the fluororesin composition is blended as described above, the friction member of the pressing member for the accelerator operating resistance generator according to the present invention significantly increases the wear resistance and creep deformation resistance of the fluororesin composition by the action of the compounding agent. improves.

  The present invention relates to a pressing member for an accelerator operating resistance generator that applies a frictional resistance to a rotating shaft that directly or indirectly drives an engine output control device and applies a resistance force to an accelerator operation. Is composed of a sheet-like friction member and a metal plate-like member, and the friction member is a fluorine resin containing at least one compounding agent selected from whisker having a Mohs hardness of 5 or less, carbon fiber, and hard resin powder. Since it is formed of a resin composition, the fluororesin is at least one resin selected from a tetrafluoroethylene resin and a modified tetrafluoroethylene resin. In addition, the wear resistance and creep deformation were greatly improved. As a result, the accelerator operation feeling is improved and an accelerator operation resistance generator having a longer life than that of the conventional product can be obtained.

As an embodiment of the present invention, FIG. 1 shows an example of an accelerator operating resistance generator installed at the shaft end of a rotating shaft extending from an accelerator sensor unit.
The accelerator operation resistance generator 1 is installed at the shaft end portion of the rotating shaft 4 that extends from the accelerator sensor unit 10 and is supported by the rolling bearing 7, and is accommodated in the housing.
In the housing, a rolling bearing 7, a spacer 8, a spring washer 9, and a pressing member are provided in the axial direction of the rotary shaft 4 in order from the bottom of the housing.
The pressing member is composed of a sheet-like friction member 2 for an accelerator operation resistance generator having both an appropriate frictional force and slidability, and a plate-like member 3 made of a metal disk to prevent deformation such as deflection. Then, the friction member 2 is bonded to the plate-like member 3. In addition, the protrusion 3a is formed in the outer-diameter part of the plate-shaped member 3, and the plate-shaped member 3 cannot be rotated by fitting in the recessed part 6 in a housing.
A metal disk 5 which is a counterpart member of the friction member 2 is firmly fixed to the end of the rotating shaft 4 by a bolt, and rotates as the rotating shaft 4 rotates.
The rotating shaft 4 is rotated by the operation of the accelerator lever 12 bound to the wire cable 11 when the accelerator is stepped on, and reversely rotated by the return force of the return spring 14 when the accelerator is returned.
The convex contact portion 2a formed on the friction member 2 is brought into pressure contact with the metal disk 5 by a spring washer 9, and when the rotary shaft 4 rotates in reverse by the return force of the return spring, friction force is generated by the friction resistance generated by this pressure contact. appear. The frictional force generated on the rotating shaft 4 becomes the resistance of the accelerator operation. Reference numeral 13 denotes an output terminal.

The friction member has an appropriate frictional force and sliding property, and has a whisker having a Mohs hardness of 5 or less, a carbon fiber, or a fluororesin as a matrix resin so that it can sufficiently withstand abrasion resistance and creep deformation. The hard resin powders are blended individually or as a mixture.
When a whisker having a Mohs hardness of 5 or less is blended, a friction member capable of achieving both wear resistance and creep resistance while maintaining an appropriate frictional force and slidability can be obtained.
The whisker having a Mohs hardness of 5 or less is preferably a single crystal having an aspect ratio of 10 or more.
Specifically, potassium titanate whiskers (Mohs hardness 3-4), calcium sulfate whiskers (Mohs hardness 3), magnesium sulfate whiskers (Mohs hardness 2-3), wollastonite (Mohs hardness 4-5), zinc oxide Examples include whiskers (Mohs hardness 4) and calcium carbonate whiskers (Mohs hardness 3-4).

Since these whiskers play a role of micro reinforcement in the fluororesin composition, the creep resistance and wear resistance of the friction member are remarkably improved. Whisker is a short fiber and has a large proportion of friction on the friction surface.
However, if the whisker fiber length is too short, sufficient creep resistance and wear resistance cannot be obtained. Therefore, the fiber length is preferably around 50 μm. The whisker corresponding to this includes anhydrous salt type and hemihydrate type of calcium sulfate whisker, preferably anhydrous salt type.

  Specific examples of commercially available whiskers include Franklin fiber A-30 (anhydrous salt type) and Franklin fiber H-30 (hemihydrate type) as calcium sulfate whiskers (fiber length 50-60 μm, Dainichi Seika Kogyo Co., Ltd.) ) Tismo N (fiber length 10-20 μm, manufactured by Otsuka Chemical Co.) as potassium titanate whisker, Panatetra (fiber length 2-50 μm, manufactured by Matsushita Electric Industrial Co., Ltd.) as zinc oxide whisker, Mosheidi (fiber length) as magnesium sulfate whisker 10-30 μm, manufactured by Ube Industries, Ltd.).

In addition, even if carbon fiber is blended in place of whisker having a Mohs hardness of 5 or less, a friction member capable of achieving both wear resistance and creep resistance while maintaining appropriate frictional force and slidability can be obtained.
The carbon fiber may be either pitch-based or bread-based carbon fiber, and the fiber length is preferably a milled fiber having a range of 0.05 mm to 0.1 mm. The fiber type is not particularly limited, but a 1000 ° C. baked product (carbonized product) is preferable to a 2,000 ° C. baked product or a processed product (graphitized product) at a higher temperature. Moreover, either a low-temperature fired product aiming at low elasticity or a high-temperature fired product aiming at high elasticity can be used. The fiber diameter is φ20 μm or less, preferably φ5 μm to φ15 μm, and the aspect ratio is 5 to 80, preferably 20 to 50.
Specific examples of commercially available carbon fibers include Crecamilde M101S (manufactured by Kureha Chemical Co., Ltd.) and Donacarbon S241 (manufactured by Osaka Gas Chemical Co., Ltd.) as pitch-based carbon fibers, and Besfight HTA-CMFO160 as bread-based carbon fibers. -0H (manufactured by Toho Rayon Co., Ltd.).

  The same effect can be obtained by blending hard resin powder in place of whisker having a Mohs hardness of 5 or less. Here, the hard resin powder is a resin powder that does not deform at a molding temperature of 380 ° C. of PTFE or modified PTFE as a matrix resin, and can be improved in creep resistance and wear resistance such as PTFE. Resin powder. Specifically, thermoplastic polyimide resin (manufactured by Mitsui Chemicals), thermosetting polyimide resin (manufactured by Furon, Ube Industries, Ltd.), polyether ether ketone resin (manufactured by Victrex MC), wholly aromatic polyester resin (Sumitomo) Chemical Industry Co., Ltd.), aromatic polyamide resin (Sumitomo Chemical Co., Ltd.), polyamideimide resin (Mitsubishi Kasei Co., Ltd.), epoxy resin, phenol resin and the like.

In consideration of moldability and the like, a hard resin powder obtained by heat-curing and grinding at a high temperature of 500 ° C. or higher after curing the thermosetting resin is preferable. Further, carbonized at 1,000 ° C. or higher and graphitized at 2,000 ° C. or higher are preferable. Examples of the thermosetting resin include an epoxy resin, a polyimide resin, and a phenol resin. The average particle size after pulverization is 50 μm or less, preferably 25 μm or less, and the shape is preferably spherical. In particular, a spherical powder obtained by reacting and curing phenol in a paraformaldehyde solution and then heat-treating and pulverizing at a high temperature of 500 ° C. or higher is preferable.
Examples of commercially available spherical graphitized powder include mesocarbon beads (manufactured by Osaka Gas Chemical Co., Ltd.), bel pearl (manufactured by Kanebo Co., Ltd.), unibex (manufactured by Unitika Ltd.), and microcarbon beads (manufactured by Nippon Carbon Co., Ltd.). And the like.

  The whisker, carbon fiber, and hard resin powder having a Mohs hardness of 5 or less can be used alone or as a mixture. Further, for example, a plurality of types of whiskers can be mixed and used.

PTFE and / or modified PTFE can be used in the fluororesin that is the matrix material of the friction member.
PTFE is a homopolymer of tetrafluoroethylene (tetrafluoroethylene), and Algoflon (manufactured by Ausimmont), Teflon (registered trademark, manufactured by DuPont), Fluon (manufactured by ICI), Polyflon (Daikin Industries, Ltd.) It is a fluororesin marketed under a trade name such as Such PTFE is a resin that is softened at 310 to 390 ° C. and can be compression-molded and extruded, but cannot be normally injection-molded.

The modified PTFE suitable for the present invention is a modified PTFE composed of a tetrafluoroethylene unit and a substituted tetrafluoroethylene unit in which the fluorine of tetrafluoroethylene is substituted with another organic group (-X). . The general formula is shown in Chemical Formula 1. The organic group (-X) is not particularly limited, but is preferably a perfluoroalkyl ether group or a fluoroalkyl group. When the modified PTFE shown in Chemical Formula 1 is used, the creep resistance is improved.
(Chemical formula 1)
-[-CF ₂ -CF _2- ] _m -[-CFX-CF _2- ] _n-
As a polymerization method of PTFE and modified PTFE, either a suspension polymerization method for polymerizing a general molding powder or an emulsion polymerization method for polymerizing a fine powder can be adopted, but the molecular weight is preferably about 500,000 to about 10 million, and further limited. From 1 million to 7 million is preferable.
Specific examples of the modified PTFE on the market include Teflon TG70J (Mitsui / DuPont Fluorochemical), Polyflon M111 (Daikin Industries), Hostaflon TFM1600 (Hoechst), and the like.

  The blending amount of at least one compounding agent selected from whisker having a Mohs hardness of 5 or less, carbon fiber, and hard resin powder is preferably 5 to 40 parts by volume with respect to 100 parts by volume of PTFE. Molding becomes difficult when the compounding amount exceeds 40 parts by volume. In addition, if it is less than 5 parts by volume, there is no significant effect on wear resistance and creep resistance.

The materials used in Examples and Comparative Examples are shown below.
Fluororesin PTFE; Teflon 7J (Mitsui / DuPont Fluorochemicals)
Modified PTFE; Teflon TG70J (Mitsui / DuPont Fluorochemicals)
Formulation Calcium sulfate whisker (anhydrous salt type, Mohs hardness 3); Franklin fiber A30 (manufactured by Dainichi Seika Kogyo Co., Ltd.)
Wollastonite whisker (Mohs hardness 4.5); Chemolit (Maruwa Biochemical Co., Ltd.)
Aluminum borate whisker (Mohs hardness 7); Arborex-Y (manufactured by Shikoku Chemicals)
Aluminum oxide whisker (Mohs hardness 9)
Carbon fiber (pitch type); Crecamill M101S (manufactured by Kureha Chemical Industry Co., Ltd.)
Glass fiber: MF-KAC (Asahi Fiber Glass)
Polyimide resin powder (thermosetting); (Furon)
Polyamideimide resin powder; (Mitsubishi Kasei Co., Ltd.)

Examples 1 to 6 and Comparative Examples 1 to 3
Using the above materials, dry blending the composition shown in Table 1 using a Henschel dry mixer, pre-molding a cylindrical shape of φ124mm x φ64mm x 100mm with a press machine, 370 ° C x 4 hours, free baking method Baked in. Further, it was skived to a thickness of 2 mm to obtain a ring-shaped sheet test piece of φ50 mm × φ40 mm × 2 mm. Then, one side of the ring sheet was etched by alkali treatment so that it could be bonded, and bonded to one side of a stainless steel jig (φ50 mm × φ15 mm × 4 mm) using an epoxy adhesive to obtain an evaluation test piece.
Using this evaluation test piece, the following evaluation test required as a friction member of the pressing member for the accelerator operating resistance generator was performed.

1) Friction test: Friction coefficient measured at initial (before endurance test) and after endurance test described below in stainless steel as the mating material under conditions of rotation speed 2.0m / min., Load 8kgf, ambient temperature 80 ℃ did.
2) Endurance test: An endurance test of 3 million cycles was performed under conditions of rocking angle ± 75 degrees, speed 1 Hz, load 8 kgf, ambient temperature 80 ° C, and air. Evaluation is almost the same as the wear resistance before and after the endurance test as wear resistance, the change in thickness as creep resistance, and the change in the sliding surface of the other material visually observed as the other material aggression. The case where there was no change was evaluated by ○, the case where slight change was observed was evaluated by Δ, and the case where there was a large change was evaluated by ×. The measurement results are shown in Table 1.

As is clear from the results in Table 1, the friction coefficient of the pressing member for an accelerator operating resistance generator according to the present invention was almost the same as the initial value even after the durability test. It was also found to be excellent in wear resistance and creep resistance. Furthermore, it was recognized that it was not aggressive against the opponent.
From this, it can be said that the friction member of the present invention is suitable as a friction member of the accelerator operation resistance generator.
The friction member having the composition of the comparative example was inferior in durability to the example (Comparative Example 1), or because the Mohs hardness exceeded 5, the opponent attack was large (Comparative Example 2 and Comparative Example 3). ). In Comparative Example 1 containing no compounding agent, the test was stopped because the friction member was worn by 1 million cycles.

  The pressing member of the present invention has a sheet-like friction member that has both an appropriate frictional force and sliding property, and has greatly improved wear resistance and creep deformation. It can be suitably used as a contact member.

It is a figure which shows an example of an accelerator operation resistance generator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Accelerator operation resistance generator 2 Friction member 3 Plate-shaped member 4 Rotating shaft 5 Disc 6 Recessed part 7 Rolling bearing 8 Spacer 9 Spring washer 10 Accelerator sensor unit 11 Wire cable 12 Accelerator lever 13 Output terminal 14 Return spring

Claims (6)

In the pressing member for the accelerator operating resistance generator that applies frictional resistance to the rotating shaft that directly or indirectly drives the engine output control device and applies resistance to the accelerator operation,
The pressing member is composed of a sheet-like friction member and a metal plate-like member,
The friction member is formed of a fluororesin composition in which at least one compounding agent selected from whisker having a Mohs hardness of 5 or less, carbon fiber, and hard resin powder is blended with fluororesin,
When the accelerator is operated, the friction member is pressed against the metal mating member fixed to the rotating shaft, and is rotated relative to the metal mating member in the forward and reverse directions, thereby causing a difference between the accelerator pedal depression force and the return force. A pressing member for an accelerator operating resistance generator.   2. The pressing member for an accelerator operating resistance generator according to claim 1, wherein the pressing member is formed by bonding a sheet-like friction member and a metal plate-like member.   The protrusion is formed in the outer diameter of the metal plate-shaped member of the said pressing member, and it cannot be rotated by fitting in the recessed part in a housing, The Claim 1 or Claim 2 characterized by the above-mentioned. A pressing member for an accelerator operating resistance generator.   4. The accelerator operating resistance generator according to claim 1, wherein the fluororesin is at least one resin selected from a tetrafluoroethylene resin and a modified tetrafluoroethylene resin. Pushing member.   The pressing member for an accelerator operating resistance generator according to any one of claims 1 to 4, wherein the whisker is a single crystal having an aspect ratio of 10 or more.   6. The hard resin powder is a polyimide resin powder or a polyamide-imide resin powder, and is blended in an amount of 5 to 25 parts by volume with respect to 100 parts by volume of the fluororesin. A pressing member for an accelerator operating resistance generator according to one item.

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