JP5929507B2 - Power transmission chain inspection method and inspection device - Google Patents

Description

  The present invention relates to a power transmission chain inspection method and inspection device, and more particularly to a power transmission chain inspection method and inspection device suitable for a continuously variable transmission (CVT) such as an automobile.

  2. Description of the Related Art Conventionally, a power transmission chain that includes a plurality of links and a plurality of first pins and a plurality of second pins that connect the plurality of links so as to bend each other is known. In Patent Document 1, in order to improve durability, in the manufacturing process, tension is preliminarily applied (pre-tensioned) to the power transmission chain, and an appropriate residual compressive stress is applied to the link. An inspection method for measuring the circumference of the power transmission chain is disclosed.

JP 2008-209190 A

  In the power transmission chain of the above-mentioned Patent Document 1, there is a possibility that an attachment failure (such as a link disconnection) may occur during the process of attaching a plurality of links to pins. Conventionally, link missing has been visually inspected, but since it has not been inspected by measurement values, there has been a problem that link missing cannot be reliably detected. Patent Document 1 describes that the circumference of the power transmission chain is measured, but there is no description on how to use the measured circumference of the power transmission chain.

  An object of the present invention is to reliably detect the disconnection of a link by using a measured value of the circumference of a power transmission chain.

An inspection apparatus for a power transmission chain according to the present invention is a method for inspecting a power transmission chain that is used by being wound between two pulleys comprising a plurality of links and a plurality of pins connecting the plurality of links. A pretensioning step of applying a pretension to the power transmission chain by winding the power transmission chain between a first tensioning pulley and a second pretensioning pulley; When there is no link omission , the maximum principal stress value generated within the link is less than the elastic limit, and when there is a link omission, the maximum principal stress value generated within the link is greater than or equal to the elastic limit. to increase the pretension to a certain value, then the pretension being maintained at the constant value, by measuring the circumference of a predetermined time period the power transmission chain, said over time When the circumference of the force transmission chain continues to increase, it is to determine a link missing has occurred.

A power transmission chain inspection apparatus according to the present invention includes a plurality of links and a plurality of pins connecting the plurality of links, and a pre-tension having a predetermined magnitude is applied to a power transmission chain that is used by being wound between two pulleys. An inspection device that is provided in a device for applying a pre-tension, and inspects whether or not the link of the power transmission chain has been disconnected. A length measuring means, a circumference increasing amount calculating means for calculating the amount of increase in the circumference of the power transmission chain obtained by the circumference measuring means, and a maximum principal stress value generated inside the link when there is no missing link Is less than the elastic limit, and if there is a missing link, the pretension is increased to a certain value so that the maximum principal stress value generated inside the link is equal to or greater than the elastic limit. Increase of the circumferential length of the power transmission chain is one that has an as determination unit link missing occurs in the case of a positive at the time maintained in a state of being held in the constant value of the tension .

  According to the power transmission chain inspection method and the inspection device of the present invention, in the pretensioning step using the pretensioning device that has been conventionally performed, the presence / absence of a link disconnection using the circumference of the power transmission chain is determined. Is possible. Thereby, it is not necessary to rely on visual determination, and it is possible to reliably detect missing links.

FIG. 1 is a plan view showing a part of an embodiment of a power transmission chain as an example targeted by a power transmission chain inspection method and inspection apparatus according to the present invention. FIG. 2 is a front view showing a state in which the power transmission chain is attached to the pulley. FIG. 3 is a diagram schematically illustrating an embodiment of a power transmission chain inspection method and inspection apparatus. FIG. 4 is a graph showing the characteristics of the circumference change used in the power transmission chain inspection method and inspection apparatus.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a part of a power transmission chain as an example targeted by a power transmission chain inspection method and inspection device according to the present invention.

  The power transmission chain (1) includes a plurality of links (11), and a plurality of first pins (14) and a plurality of second pins (15) that connect the plurality of links (11) in a bendable manner. Yes.

  The link (11) has a front insertion part (12) located on the front side in the chain traveling direction and a rear insertion part (13) located on the rear side in the chain traveling direction.

  The power transmission chain (1) is a link unit consisting of a plurality of links arranged in the chain width direction and arranged in three in the chain traveling direction (front-rear direction) to form one link unit. Are connected in the chain traveling direction. In this embodiment, one link unit includes a link row having nine links and two link rows having eight links.

  The links (11) are overlapped so that the front insertion part (12) of one link (11) on the rear side in the traveling direction corresponds to the rear insertion part (13) on the other link (11) on the front side in the traveling direction. ing. Each first pin (14) and each second pin (15) are fitted into a plurality of front insertion parts (12) and rear insertion parts (13) that overlap in the chain width direction.

  The power transmission chain (1) is used in a continuously variable transmission (10) as a power transmission device. As shown in FIG. 2, the continuously variable transmission (10) includes a pair of pulleys (only one pulley is shown) (2) and a power transmission chain (1) wound around both pulleys (2). It has.

  The pulley (2) includes a fixed sheave (2a) fixed to the pulley shaft (2e) and a movable sheave (2b) supported on the pulley shaft (2e) so as to be movable in the axial direction. The fixed sheave (2a) and the movable sheave (2b) have conical face-like sheave surfaces (2c) and (2d) that face each other.

  Both end surfaces of the first pin (14) are sandwiched between a pair of opposed sheave surfaces (2c) (2d) of the pulley (2), and both end surfaces of the first pin (14) and each sheave surface (2c) ) (2d), power is transmitted between the power transmission chain (1) and the pulley (2). The movable sheave (2b) is pressed to the fixed sheave (2a) side by a hydraulic actuator (not shown), so that a clamping force for clamping the power transmission chain (1) is applied to the pulley (2). It is done.

  In FIG. 2, when the movable sheave (2b) of the pulley (2) at the position indicated by the solid line is moved closer to or away from the fixed sheave (2a), the power transmission chain (1) is wound around the pulley (2). The diameter is large when approaching and is small when separated, as indicated by the chain line in FIG.

  In the other pulley (not shown) of the pair of pulleys (2), the fixed sheave is disposed on the opposite side in the axial direction from the illustrated fixed sheave (2a) with the power transmission chain (1) in between. Yes. The movable sheave moves in the opposite direction to the movable sheave (2b) of the pulley (2) shown. As a result, the gear ratio of the continuously variable transmission (10) changes steplessly.

  The link (11) is made of, for example, spring steel or carbon tool steel. The material of the link (11) is not limited to spring steel or carbon tool steel, but may of course be other steel such as bearing steel. In the link (11), the front and rear insertion parts (12) and (13) may be independent through holes (links with columns), and the front and rear insertion parts (12) and (13) have one through hole (no columns). Link). As the material of the first pin (14) and the second pin (15), appropriate steel such as bearing steel is used.

  The power transmission chain (1) has the required number of first pins (14) and second pins (15) arranged in a vertical arrangement at a predetermined pitch and held in an assembled state when assembled as a chain. This is manufactured by sequentially press-fitting the links (11). The press-fitting is performed between the inner radial edge of each pin (14) (15) in the chain radial direction and the inner radial edge of the link (11) and on the outer side of each pin (14) (15) in the chain radial direction. This is performed between the edge and the outer edge of the link (11) in the chain radial direction. The press-fitting allowance is set to 0.005 mm to 0.1 mm.

  During this manufacturing, an abnormality may occur in the link press-fitting process, and the manufacturing process may be completed in a state where one or a plurality of links (11) are not arranged at a predetermined location. Such defects (link missing) can be detected by visually observing whether or not the link (11) is missing, but since a large number of links (11) are used, only visual judgment is necessary. The missing link (11) may not be detected completely.

  The power transmission chain inspection method and inspection apparatus described below are for detecting a link disconnection by using a measured value of the circumference of the power transmission chain.

  FIG. 3 shows a pretensioning device provided with an inspection device.

  The pretensioning device (31) includes a first pulley (32), a second pulley (33), a rotation driving device (34), a traveling direction moving table (35), and a traveling direction driving device (36). , A load sensor (pretension measuring means) (37), a position sensor (perimeter measuring means) (38), and a control unit (39). The control unit (39) is configured as a general computer such as a ROM storing a program in addition to a CPU and a memory (RAM) (not shown).

  The rotation drive device (34) rotates the rotation shaft of the first pulley (32). The traveling direction moving table (35) is driven by the traveling direction drive device (36), thereby moving the second pulley (33) in the chain traveling direction to approach the distance between the axes of the pulleys (32) and (33). Alternatively, the tension acting on the power transmission chain (1) is adjusted by separating them. The load sensor (37) measures the pretension. The position sensor (38) detects the position of the second pulley (33) in order to calculate the circumference of the power transmission chain (1). The control unit (39) controls the rotation drive device (34) and the traveling direction drive device (36), and processes the outputs of the load sensor (37) and the position sensor (38).

  The control unit (39) includes a rotation drive processing unit (41) that controls the drive of the rotation drive device (34), a travel direction drive processing unit (42) that controls the drive of the travel direction drive device (36), and a load sensor. A pretension processing unit (43) for controlling the pretension based on the output of (37), a circumferential length processing unit (44) for controlling the circumferential length based on the output of the position sensor (38), and the like are provided. The circumference of the power transmission chain (1) is determined between the shafts of the first pulley (32) and the second pulley (33) determined based on the position of the second pulley (33) measured by the position sensor (38). The distance L, the diameter D1 from the axial center of the first pulley (32) to the contact portion between the first pulley (32) and the power transmission chain (1), which are stored in the control unit (39) in advance, Using the diameter D2 from the shaft center of the two pulleys (33) to the contact portion between the second pulley (33) and the power transmission chain (1), the circumference is calculated as follows: circumference = π (D1 + D2) + 2L.

  The control unit (39) further includes a circumferential length increase amount calculating means (45) for calculating an increase amount of the circumferential length obtained by the circumferential length processing unit (44) at predetermined intervals, and the pretension is made constant. A determination means (46) for determining a defective product when the circumferential length increase amount at the time is positive is added.

  In the pretensioning device (31), the magnitude of the applied tension is set so that the maximum principal stress value generated in the link (11) is not less than the elastic limit of the link (11) and not more than the plastic limit. As a result, an appropriate residual compressive stress is applied to the inside of the link (11).

  The graph shown in FIG. 4 shows the change in the circumference of the power transmission chain (1) during pretensioning. In the normal product indicated by the solid line, first, when the pretension is increased, the circumference increases, and at the stage where the pretension is constant, the circumference does not increase. Return to the length. On the other hand, the defective link missing product indicated by the broken line is insufficient in strength because the link (11) is missing compared to the normal product. The length increases and the perimeter increases even when the pretension is constant. That is, the inclination θ shown in the figure is positive. Accordingly, the missing link (11) can be detected by looking at the increase in the circumference (slope θ).

  When the circumference of the power transmission chain (1) increases with a certain amount of pretension applied, the increase rate of the circumference is the threshold value stored in advance in the control unit (39). Control that detects an abnormal product of the power transmission chain (1) such as a link disconnection may be performed.

  The apparatus shown in FIG. 3 is obtained by adding a function for inspecting defective products (missing of the link (11)) to the pretension applying apparatus based on the above knowledge. ) Is a part constituting a defective product inspection apparatus. In this embodiment, it is determined whether the product is defective by using the circumference of the power transmission chain (1) in the pretensioning step. Specifically, after the pretension reaches a certain value, the circumference of the power transmission chain (1) is measured for a predetermined time, and the increase amount (slope θ) of the circumference of the power transmission chain (1) is calculated. When the circumference of the power transmission chain (1) continues to increase with time (θ> 0), it is determined as a defective product. Thereby, it is not necessary to rely on the visual determination of the missing link (11), and the missing link (11) can be reliably detected.

(1): Power transmission chain, (2) (3): Pulley, (11): Link, (14): First pin, (15): Second pin, (31): Pretensioning device, (32 ): First pulley for applying pretension, (33): second pulley for applying pretension, (37): load sensor (pretension measuring means), (38): position sensor (perimeter measuring means), (45) ): Circumference increase amount calculation means, (46): Determination means

Claims (2)

A method for inspecting a power transmission chain comprising a plurality of links and a plurality of pins connecting the plurality of links and being wound between two pulleys.
A pretensioning step of applying a pretension to the power transmission chain by winding the power transmission chain between a first pretensioning pulley and a second pretensioning pulley;
In the pre-tensioning step, the maximum principal stress value generated inside the link is less than the elastic limit when there is no missing link, and the maximum principal stress value generated inside the link is elastic when there is a missing link. The pretension is increased to a certain value so as to exceed the limit, and then the circumference of the power transmission chain is measured for a predetermined time while the pretension is held at the certain value, and the power transmission chain is increased over time. A method for inspecting a power transmission chain that determines that a link drop has occurred when the circumference of the shaft continues to increase. The power transmission is provided in a device for applying a pre-tension of a predetermined magnitude to a power transmission chain which is composed of a plurality of links and a plurality of pins connecting the plurality of links and is wound between two pulleys. An inspection device for inspecting the chain for missing links
Pretension measuring means;
A circumference measuring means for measuring the circumference of the power transmission chain at the time of applying a pretension for a predetermined time;
A circumference increase amount calculating means for calculating an increase amount of the circumference of the power transmission chain obtained by the circumference measuring means;
If there is no missing link, the maximum principal stress value generated in the link is less than the elastic limit, and if there is a missing link, the maximum principal stress value generated in the link is predicted to be greater than the elastic limit. When the tension is increased to a certain value and then the pre-tension is maintained at the certain value , the link disconnection occurs when the increase in the circumference of the power transmission chain is positive . And a power transmission chain inspection device.

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