JP2002364664A - Sliding key structure and continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sliding key structure of preventing generation of malfunc tion or the like even under the operating environments of high temperature and high load and of attaining high productivity, and also to provide a continu ously variable transmission provided with the structure capable. SOLUTION: A sliding cylinder is engaged with a rotating shaft so that sliding may be performed in the axial direction of the rotating shaft and following may be performed in the rotating direction, and sliding key sliding section formed inside a groove section recessed in the sliding cylinder is made of resin body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding key structure suitable for use in a special environment such as high-temperature non-lubrication and a continuously variable transmission provided with the sliding key structure.

[0002]

2. Description of the Related Art As a pulley structure of a continuously variable transmission using a sliding key, a pulley of a continuously variable transmission in which a fixed pulley that rotates integrally with a rotating shaft and a movable pulley that has a sliding cylinder are engaged by a sliding key. The structure is known.
8-219258). Referring to FIG. 6, a pulley structure of a conventional continuously variable transmission will be described. FIG. 6 shows an axial half-section of the pulley structure. A rotating shaft 4 driven by an engine (not shown) is driven by bearings 5a and 5b to form a transmission main body 6.
It is supported by A fixed pulley 7 is integrally formed on the rotating shaft 4 so as to protrude outward. A stepped portion 4a formed on the outer periphery of the rotating shaft 4 has an elongated hole formed in the outer periphery thereof in the longitudinal direction. Depressed grooves 4b are formed at regular intervals in the circumferential direction. A slide key 3 is fitted into the groove 4b, and a movable pulley 8 having a slide cylinder 8a slidably engaged with the fixed pulley 7 by the slide key 3 is engaged. . The sliding key 3 fitted into the groove 4b is mainly used for preventing rotation or for transmitting power.
Further, an axial reciprocating function is also required as an additional function. In FIG. 6, reference numeral 9 denotes a V-belt mounted between the fixed pulley 7 and the movable pulley 8.

Conventionally, the sliding key 3 has been formed mainly of metals and materials having a small coefficient of friction. As a material having a small friction coefficient, for example, a material obtained by mixing a polyimide resin, a polytetrafluoroethylene resin and graphite, or a material obtained by mixing a polyetheretherketone resin, carbon fiber, and a polytetrafluoroethylene resin is used. Was. However, when the sliding groove made of metal is made of metal, the metal slides with each other, especially in high-temperature, high-load operating environments. Problem. If a ball spline structure or the like is used instead of metal, the structure becomes complicated and expensive. Furthermore, even in the case of a conventional sliding key made of a resin material having a low coefficient of friction, even in a high-temperature, high-load use environment,
There is a problem that it is deformed or has high frictional resistance and is broken in a short time. As a sliding key for solving these problems, an integrally molded product of a resin body and a metal body is known (Japanese Patent Laid-Open No. 2000-55067).

[0004]

However, a sliding key made of an integrally molded product of a resin body and a metal body has a problem that an integral molding process is required in manufacturing, the number of steps is increased, and the manufacturing cost is increased. is there. Further, there is another problem that, particularly in a high-temperature, high-load use environment, the frictional resistance increases due to seizure or rust between the metals, and it is not possible to sufficiently suppress the occurrence of operation failure or inoperability.

SUMMARY OF THE INVENTION The present invention has been made to address such a problem, and does not cause malfunction or inoperability even in a high-temperature, high-load use environment, and has excellent productivity. It is an object of the present invention to provide a continuously variable transmission having a key structure and a sliding key structure.

[0006]

A sliding key structure according to the present invention comprises a sliding cylinder engaged with the rotating shaft so as to be slidable in the axial direction of the rotating shaft and to be able to follow the rotating direction. The sliding key sliding portion on the rotation shaft or the inner surface of the groove formed in the slide cylinder is made of a resin body. Further, the resin body is a molded body of a resin composition that can be injection-molded.

In the sliding key structure according to the present invention, the sliding key whose inner surface formed in the rotary shaft or the slide cylinder is fitted into the groove made of a resin body is recessed in the mating slide cylinder or the rotary shaft to be engaged. Characterized in that it is fitted into the grooved portion. Further, the sliding key whose inner surface is fitted into the groove made of the resin body is a mating slide cylinder or a protrusion protrudingly provided on the rotary shaft to be engaged.

A continuously variable transmission according to the present invention has a fixed pulley that rotates integrally with a rotating shaft, and is slidable in the axial direction of the rotating shaft.
And a movable pulley having a slide cylinder engaged so as to be able to follow the rotation direction, wherein the sliding key structure for engaging the fixed pulley and the movable pulley is the sliding key structure of the present invention. I do.

The sliding key structure of the present invention is excellent in slidability by forming the sliding key sliding portion on the inner surface of the groove formed in the rotary shaft or the sliding cylinder into a resin body. There is no malfunction or inoperability even in a moving use environment. Particularly, by forming the resin body into a resin composition capable of being injection-molded, even a complicated shape and structure can be easily formed. For this reason, it is possible to reduce the size and weight and reduce the cost as compared with the conventional ball spline.

Since the continuously variable transmission of the present invention uses the above-mentioned sliding key structure, it has a simple structure and has a smooth operation performance in a non-lubricated atmosphere.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One example of a sliding key structure according to the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of a resin body that fits into a groove formed in a rotary shaft or a slide cylinder, and FIGS. 2 to 5 are diagrams illustrating a sliding key structure. The resin body 1 has a groove 1a that can be fitted into the outer periphery of the rotating shaft or a groove formed in the slide cylinder and into which a sliding key or a projection can be fitted. Further, a shape that cannot be moved even when a load in the axial direction is applied after fitting into the groove is preferable. The prevention of the displacement in the axial direction can be performed by a fitting shape to the groove portion, or by using a washer described later. The upper surface of the resin body 1 fitted into the groove is preferably convex or concave in an arc shape so as to have the same peripheral surface as the outer peripheral surface of the rotating shaft 4a or the inner peripheral surface of the slide cylinder 8a.

In FIG. 2, (a) is a front view showing a state in which a resin body is fitted, (b) is a sectional view showing a state in which a sliding key is fitted to a rotating shaft and a slide cylinder, (C)
The figure shows a cross-sectional view of a state in which a protrusion protruding from the slide cylinder is fitted as a slide key. The slide key structure shown in FIG. 2 is provided in a continuously variable transmission whose one example is shown in FIG. The resin body 1 is fitted, and the groove 1a of the resin body 1 is used as a key groove (FIG. 2A).
The groove portion 4b is formed at at least one position, preferably at a plurality of positions at equal intervals in the circumferential direction. Next, the slide key 3 is fitted into the groove 1a and the key groove 8b formed on the inner peripheral surface of the slide cylinder 8a, and a slide key structure in which the rotary shaft 4 and the slide cylinder 8a are engaged is obtained (FIG. 2 (b)). Also, instead of the slide key 3, a projection 8c protruding from the inner peripheral surface of the slide cylinder 8a.
May be a sliding key structure obtained by fitting into the groove 1a of the resin body 1 (FIG. 2C).

The step portion 4a in the sliding key structure shown in FIG.
3A is a perspective view, and FIG. 3B is a cross-sectional view. A groove 4b is formed in a stepped portion 4a formed on the outer periphery of the rotating shaft 4 in a long hole shape in the outer periphery longitudinal direction, and further has an insertion groove having a groove width in which the sliding key 3 can be inserted from the end in the same longitudinal direction. 4d is recessed. Resin body 1 in groove 4b
Are fitted, the groove 1a of the resin body 1 becomes a key groove, and the sliding key 3 is fitted. The slide key 3 that can be inserted from the end is prevented from shifting in the axial direction by using the washer 2.

4A is a front view showing a state in which the resin body 1 is fitted, and FIG. 4B is a sectional view showing a state in which a sliding key is fitted to the rotary shaft and the slide cylinder. ,
(C) is a cross-sectional view showing a state in which a protrusion protruding from the rotating shaft is fitted as a sliding key. FIG.
Shows a partial perspective view of FIG. In the sliding key structure shown in FIG. 4, the resin body 1 is fitted into a groove 8d recessed on the inner peripheral surface of the slide cylinder 8a, and the groove 1a of the resin body 1 is used as a key groove (FIG. 4A). ). The grooves 8d are formed at at least one position, preferably at a plurality of positions at equal intervals in the inner circumferential direction. Next, the slide key 3 is fitted into the groove 1a and the groove 4c formed in the step 4a of the rotary shaft 4 to obtain a slide key structure in which the rotary shaft 4 and the slide cylinder 8a are engaged (FIG. 4 (b)). Further, instead of the sliding key 3, a sliding key structure obtained by fitting a projection 4d projecting from the step portion 4a of the rotating shaft into the groove 1a of the resin body 1 may be used (FIG. 4C).

The groove 8d in the sliding key structure shown in FIG.
5A is a perspective view, and FIG. 5B is a cross-sectional view. A groove 8d is formed in a long hole shape in the longitudinal direction of the inner peripheral surface of the slide cylinder 8a. The resin body 1 is fitted into the groove 8d, and the groove 1a of the resin body 1 becomes a key groove. The sliding key fitted into the key groove is prevented from shifting in the axial direction by using the washer 2.

In the sliding key structure shown in FIG. 2, the portion sliding with the sliding key 3 or the inner peripheral projection 8c becomes the groove 1a of the resin body 1, so that the sliding property in the axial direction is improved. Further, by forming the sliding key 3 as a metal molded body, the fitting force of the sliding key is improved. Similarly, in the sliding key structure shown in FIG. 4, the portion sliding with the sliding key 3 or the protrusion 4 d becomes the groove 1 a of the resin body 1, so that the slidability in the axial direction is improved.
Further, by forming the sliding key 3 as a metal molded body, the fitting force of the sliding key is improved.

As the sliding key 3, a machined product, a forged product, a lost wax product, a sintered metal product, a metal injection product, or the like can be used. Of these, lost wax products are preferred for reasons such as strength reliability and cost.
Further, surface treatment such as plating can be performed to prevent rust on the surface. Further, the slide key 3 can be used even if it is an integrally molded product of a resin body and a metal body.

The resin composition for forming the resin body 1 can be formed by injection molding, compression molding, transfer molding, or the like. Among these, a resin composition that can be injection-molded is preferable. This is because even if the fitting groove has a complicated shape, it can be easily formed. Examples of resin components that can be injection-molded include thermoplastic polyimide resins, polyether ketone resins and polyether ketone resins such as polyether ketone resins, polyacetal resins, polyamide resins, polyethylene resins, polyamide imide resins, polyether nitrile resins, Examples thereof include aromatic polyester resins and polyphenylene sulfide resins. These can be used alone or in a polymer blend of two or more resins. Among these, a thermoplastic polyimide resin and a resin containing a polyetherketone resin as a main component, which can provide a sliding key having excellent mechanical strength and slidability, are preferable.

As shown in Chemical Formula 1, an imide group having excellent thermal characteristics, mechanical strength and the like surrounds an aromatic group in a repeating unit of a molecular structure. Imide resin having a structure having a plurality of ether bond parts showing appropriate melting characteristics by adding a resin is preferable, and in order to satisfy mechanical properties, rigidity, heat resistance and injection moldability, the ether bond part is repeated in a unit. A thermoplastic polyimide resin having two units is preferred.

[0020]

Embedded image (Wherein, X is a direct bond or a hydrocarbon group having 1 to 10 carbon atoms,
Hexafluorinated isopropylidene group, carbonyl group,
Represents a group selected from the group consisting of a thio group and a sulfone group, wherein R _{1 to} R ₄ are hydrogen, a lower alkyl group (preferably having 1 to 5 carbon atoms), a lower alkoxy group (preferably having a carbon number of 1 to 5);
1 to 5), chlorine or bromine, which may be the same or different. Y is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group, a condensed polycyclic aromatic group, or a non-condensed polycyclic ring in which aromatic groups are connected to each other directly or by a cross-linking group. Represents a tetravalent group selected from the group consisting of formula aromatic groups. Examples of such a thermoplastic polyimide resin include AURUM (trade name, manufactured by Mitsui Toatsu Chemicals Co., Ltd.) in which all of R _{1 to} R _{4 in} Chemical Formula ₁ are hydrogen.

The polyetherketone resin is a resin having a repeating unit represented by the following formula (2), or a repeating unit represented by the following formula (3) together with such a repeating unit does not lose the original properties of the polyetherketone resin. It refers to a resin that coexists to a certain extent.

[0022]

Embedded image

[0023]

Embedded image

As a commercially available product of such a polyetherketone resin, PEEK150P (Victrex (V
ICTREX), brand name), PEK220G (ICI)
Company, product name), Ultrapek A2000 (BASF
Company, trade name).

The resin composition constituting the resin body 1 includes a solid lubricant such as tetrafluoroethylene resin, graphite, molybdenum disulfide, tungsten disulfide, graphite fluoride, boron nitride, silicon nitride, glass fiber, carbon fiber, and the like. Reinforcing materials such as fibers and whiskers, and various fillers such as calcium carbide, clay, and mica can be blended. The resin body 1 is molded using an injection molding method obtained by injection-filling a resin composition into a mold.

The continuously variable transmission according to the present invention is characterized by having the above-mentioned sliding key structure, and the other components except for the sliding key structure are conventional components shown in FIG. Can be.

[0027]

EXAMPLES Examples 1 to 4 and Comparative Examples 1 and 2 As a resin composition, a thermoplastic polyimide resin composition (BEARY PI5010: trade name of NTN Precision Resin) and a polyetherketone resin composition ( BEAREE PK506
0: NTN precision resin product name) as a sliding key, a sliding key 3 shown in FIG.
Of each shape were prepared. Injection molding conditions (thermoplastic polyimide resin composition: pressure; 255 MPa, temperature; 410
℃, polyetherketone resin composition: pressure; 255MPa,
(Temperature: 380 ° C.) to obtain a resin body 1 having the shape shown in FIG. The first and second embodiments employ the structure shown in FIG. 2B, and the third and fourth embodiments employ the structure shown in FIG. 4B. The resin body is provided on the step portion 4a of the shaft 4. In order to fit into the oval groove 4b or the groove 8d formed in the slide cylinder, both ends in the axial direction were made to have the same shape as the groove 4b or 8d, and were set so as not to shift against the axial load. The obtained sliding key structure was evaluated by repeated shear fatigue test and friction coefficient measurement by friction test.

The repeated shear fatigue test will be described with reference to FIG. FIG. 7 shows a cyclic shear fatigue tester. The resin body 1 is fitted and fixed in the groove formed in the shaft 13, and the sliding key 3 is fitted in the housing 14 in which the metal molded body fitting groove is formed. Fit. At this time, the groove of the housing 14 and the sliding key 3 were fitted with a press-fitting allowance. A hydraulic exciter 15 and a load cell 16 for controlling a constant load are attached to the housing 14, and the sliding key 3 is repeatedly fatigued by oscillating motion about a central axis 13a of the shaft.
The test conditions were as follows: ambient temperature 120 ° C, excitation speed 10H
z, the deformation amount of the resin body 1 is set at 0.
The test was performed until the thickness became 1 mm. FIG. 7 shows FIG.
4B shows the method shown in FIG. 4B, and the method shown in FIG.
The test conditions are the same except that the fitting part of the sliding key 3 differs from that of the sliding key 3.

The friction test will be described with reference to FIG. FIG. 8 shows a friction tester. A test piece 1b in which a sliding key 3 is fitted in a groove 1a of a resin body 1 is fixed to a base 10 which receives a load by an air cylinder (not shown). As the mating member 11 of the test piece 1b, a plate material obtained by subjecting S45C to nickel-phosphorus plating is used, and a table 12 having the mating member 11 has a driving device 17 and a load cell 1 for measuring sliding resistance.
6 and reciprocate the table 12 with a stroke of 30 mm. The specific test conditions are the ambient temperature 120
° C, applied load 50MPa, reciprocating speed 1.5mm / sec. Table 1 shows the results of evaluation using plate-like test pieces 1b in this test. Comparative Examples 1 and 2 are sliding keys using a thermoplastic polyimide resin composition alone and a polyetherketone resin composition alone.

[0030]

[Table 1]

As shown in Table 1, the sliding key structures of Examples 1 to 4 exhibited a repetitive shear fatigue property three times or more as compared with the sliding key of the resin composition alone, and had a coefficient of friction. It was equivalent.

When the continuously variable transmission shown in FIG. 6 was assembled using the sliding key structures of Embodiments 1 and 3, the temperature was about 120 ° C., the load was about 250 kgf, and the sliding speed was 1.4 mm / s.
Under the use environment of ec, there was no burning or destruction.

[0033]

According to the sliding key structure of the present invention, the sliding key sliding portion on the inner surface of the groove formed in the rotating shaft or the sliding cylinder engaged with each other is made of a resin body, so that it can be used in a high-temperature, high-load operating environment. Even when used below, there is no seizure or breakage. Further, since the resin body and the slide key are separate bodies, the manufacturing process can be shortened. Further, since the resin body is made of a resin composition that can be injection molded, it can be molded even in a complicated shape. In addition, since the slide cylinder or the protrusion protruding from the rotary shaft is used as the slide key, the structure is further simplified. As a result, a sliding key structure having excellent mechanical properties and low cost can be obtained.

The continuously variable transmission according to the present invention has a fixed pulley that rotates integrally with a rotating shaft, and is slidable in the axial direction of the rotating shaft.
5. The sliding key structure according to claim 1, further comprising a movable pulley having a slide cylinder engaged so as to be able to follow the rotation direction, wherein the sliding key structure engages the fixed pulley and the movable pulley. Because of the key structure, a simple structure is possible, and a small, lightweight, low-cost continuously variable transmission can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a resin body.

FIG. 2 is a diagram illustrating a sliding key structure.

3 is a perspective view and a sectional view of the sliding key structure shown in FIG.

FIG. 4 is a diagram illustrating another sliding key structure.

5 is a perspective view and a sectional view of the sliding key structure shown in FIG.

FIG. 6 is an axial half-sectional view of a pulley structure of the continuously variable transmission.

FIG. 7 is a diagram showing a repetitive shear fatigue tester.

FIG. 8 is a view showing a friction tester.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin body 2 Washer 3 Sliding key 4 Rotary shaft 5 Bearing 6 Transmission body 7 Fixed pulley 8 Movable pulley 9 V belt

Claims (5)

[Claims] 1. A sliding key structure for engaging a slide cylinder with the rotation shaft so as to be slidable in the axial direction of the rotation shaft and to be able to follow the rotation direction. A sliding key structure, wherein a sliding portion of the sliding key on the inner surface of the provided groove portion is made of a resin body. 2. The sliding key structure according to claim 1, wherein said resin body is a molded body of a resin composition capable of being injection molded. 3. The sliding key fitted in the groove portion is fitted in a groove portion formed in a mating slide cylinder or a rotating shaft to be engaged with the sliding key.
The described sliding key structure. 4. The sliding key structure according to claim 2, wherein the sliding key fitted into the groove portion is a protrusion protruding from the sliding cylinder or the rotating shaft. 5. A fixed pulley that rotates integrally with a rotating shaft,
A continuously variable transmission having a movable pulley provided with a slide cylinder slidable in the axial direction of the rotating shaft and capable of following the rotational direction, wherein the fixed pulley and the movable pulley are engaged with each other. 5. The continuously variable transmission according to claim 1, wherein the sliding key structure is a sliding key structure.