JP2014010475A - Detent device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detent device capable of increasing the setting freedom of tightening margin between support holes in a holder and a casing of the detent device.SOLUTION: When a cross-sectional shape of an inner peripheral surface of a support hole 12c of the casing 12 and a cross-sectional shape of an outer peripheral surface of a holder 15 of a detent device 14 are coaxially overlapped with each other, the cross-sectional shape of the inner peripheral surface bridges across the inner side and the outer side of the cross-sectional shape of the outer peripheral surface. When press-fitting, the cross-sectional shape of the outer peripheral surface of the holder 15 is deformed according to the cross-sectional shape of the inner peripheral surface of a support hole 12c while generating an appropriate surface pressure (stress) on the press-fitting surface. With this, the holder 15 is prevented from dropping off while preventing the casing 12 from cracking. With this, even when the casing 12 is formed of an aluminum-based metal and the holder 15 is formed of an ion-based metal each having the thermal expansion coefficient different from each other, the setting freedom of the tightening margin of both sides can be increased.

Description

  The present invention provides a support hole formed in a casing, a cylindrical holder made of a material different from that of the casing and press-fitted into the support hole, a ball movably accommodated in the holder, and the holder A spring that is housed and biases the ball, and the ball is resiliently brought into contact with a plurality of notches formed in a shaft that is slidable in the axial direction, whereby the shaft is moved to a plurality of stop positions. The present invention relates to a detent device for positioning to any one.

  In a detent device having a cylindrical holder (sleeve), a ball movably accommodated inside the holder, and a spring disposed inside the holder and biasing the ball, the cross section formed in the casing has a perfect circle shape Patent Document 1 below discloses that a holder having a perfectly circular cross section is press-fitted into the support hole.

JP 2007-257443 A

  By the way, when the holder is press-fitted and fixed to the support hole of the casing, it is necessary to appropriately set a tightening allowance that is a dimensional difference between the inner diameter of the support hole and the outer diameter of the holder, and if the tightening allowance is excessive, the holder There is a possibility that the support hole of the casing is cracked during press-fitting, and conversely, if the tightening margin is too small, the holder may fall out of the support hole of the casing after press-fitting.

  However, if the casing and holder are made of materials with different coefficients of thermal expansion, the allowance will change because the casing and holder expand or contract at different coefficients of thermal expansion due to temperature changes, even if the allowance is set appropriately. There is a possibility that the support hole of the casing breaks or the holder falls off.

  In particular, when the casing and the holder are made of different materials, the upper limit value of the tightening allowance is restricted by a component having a lower material strength, which causes a problem that the degree of freedom in setting the tightening allowance is lowered.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to increase the degree of freedom of setting the allowance between the holder of the detent device and the support hole of the casing.

  In order to achieve the above object, according to the invention described in claim 1, a support hole formed in the casing, and a cylindrical holder made of a material different from that of the casing and press-fitted into the support hole, A ball movably accommodated in the holder, and a spring accommodated in the holder and biasing the ball, and the ball is repelled in a plurality of notches formed in a shaft slidable in an axial direction. A detent device for positioning the shaft at any of a plurality of stop positions by bringing the shaft into contact with each other, wherein the cross-sectional shape of the inner peripheral surface of the support hole and the cross-sectional shape of the outer peripheral surface of the holder are A detent device is proposed in which the cross-sectional shape of the inner peripheral surface straddles the inner side and the outer side of the cross-sectional shape of the outer peripheral surface when they are overlapped with their centers aligned.

  According to the invention described in claim 2, in addition to the configuration of claim 1, the circumference of the cross-sectional shape of the inner peripheral surface of the support hole is equal to or greater than the circumference of the cross-sectional shape of the outer peripheral surface of the holder. A detent device characterized by this is proposed.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the casing is made of an aluminum-based material, and the cross-sectional shape of the inner peripheral surface is a perfect circle. There is proposed a detent device characterized in that is a ferrous material and the outer peripheral surface has a non-circular cross-sectional shape.

  The fork shaft 11 of the embodiment corresponds to the shaft of the present invention. Further, the “center of the cross-sectional shape” of the present invention corresponds to the geometric center of gravity (centroid) in a shape having no geometric center.

  According to the configuration of claim 1, the detent device is accommodated in the support hole formed in the casing, a cylindrical holder made of a material different from the casing and press-fitted into the support hole, and movably accommodated in the holder. A ball and a spring that is housed in a holder and urges the ball, and the ball is resiliently brought into contact with a plurality of notches formed in the shaft that is slidable in the axial direction, so that the shaft is stopped a plurality of times. It can be positioned at any of the positions. When the cross-sectional shape of the inner peripheral surface of the support hole and the cross-sectional shape of the outer peripheral surface of the holder are overlapped with their centers aligned, the cross-sectional shape of the inner peripheral surface is inside and outside the cross-sectional shape of the outer peripheral surface. Therefore, when press fitting, the cross-sectional shape of the outer peripheral surface of the holder is deformed so as to follow the cross-sectional shape of the inner peripheral surface of the support hole. While avoiding, it is possible to prevent the holder from falling off. Thereby, even if it is a case where a casing and a holder are comprised with a different material and there is a difference in a thermal expansion coefficient, both setting allowances of the allowance can be increased.

  Further, according to the configuration of claim 2, since the circumferential length of the cross-sectional shape of the inner peripheral surface of the support hole is equal to or greater than the peripheral length of the cross-sectional shape of the outer peripheral surface of the holder, when the holder is press-fitted into the support hole of the casing, Freely set the tightening allowance for the support hole and holder by preventing the inner surface of the support hole and the outer periphery of the holder from coming into close contact with each other and preventing the surface pressure and stress of the press-fit surface from increasing suddenly. The degree can be secured.

  According to the third aspect of the present invention, since the casing is made of an aluminum-based material and the cross-sectional shape of the inner peripheral surface is a perfect circle, the casing, which is a large member, is made of an aluminum-based material having a small specific gravity to reduce the weight. In addition, drilling of a perfect circular support hole can be easily performed. In addition, since the holder is made of an iron-based material and the cross-sectional shape of the outer peripheral surface is non-circular, the holder, which is a small member, can be made of an iron-based material with a large specific gravity to minimize the increase in weight. In addition, even if the holder that can be pressed has a non-circular cross-sectional shape, the number of processing steps does not increase particularly.

The longitudinal cross-sectional view of the detent apparatus of the transmission for motor vehicles. (First and second embodiments) FIG. 2 is an enlarged view taken along line 2-2 in FIG. 1. (First and second embodiments) The graph which shows the relationship between the press-fitting allowance of a holder and the surface pressure or stress of a press-fit surface. (First and second embodiments) The figure corresponding to FIG. (Third embodiment)

First and second embodiments

  The first and second embodiments of the present invention will be described below with reference to FIGS.

  As shown in FIG. 1, a fork shaft 11 that supports a shift fork of an automobile transmission is slidably supported by a bush 13 that is press-fitted into a guide hole 12a formed in a casing 12 of the transmission made of an aluminum material. It is connected to a shift lever or actuator operated by the driver and moves in the axial direction. For example, three V-shaped notches 11a, 11b, and 11c are formed on the outer peripheral surface of the fork shaft 11 at predetermined intervals in the axial direction.

  The detent device 14 for positioning the fork shaft 11 at three positions in the axial direction includes three members: a holder 15, a ball 16, and a spring 17. The holder 15 is obtained by drawing an iron-based plate, and includes a cylindrical main body 15a, a bottom 15b that closes one end of the main body 15a, and a flange that is bent at the other end of the main body 15a radially outward. 15c and an air vent hole 15d opened at the center of the bottom portion 15b. The ball 16 is movably accommodated in the main body 15a of the holder 15 with a slight gap, and is urged from one end to the other end by a coiled spring 17 disposed between the ball 16 and the bottom 15b. . The air vent 15d prevents the movement of the ball 16 from being obstructed by the air being trapped in the main body 15a when the ball 16 moves in the main body 15a.

A support hole 12c is formed so as to pass through a wall portion 12b provided at a position adjacent to the guide hole 12a of the casing 12, and the main body portion 15a of the holder 15 is fixed to the support hole 12c by press-fitting. With the main body portion 15a of the holder 15 being press-fitted into the support hole 12c, the flange portion 15c of the holder 15 is in contact with the wall portion 12b and is protruded from the other end side of the main body portion 15a by the elastic force of the spring 17. The urged ball 16 engages with any of the three notches 11 a to 11 c of the fork shaft 11. FIG. 2A shows a state in which the main body 15 a of the holder 15 is press-fitted into the support hole 12 c of the casing 12. FIG. 2B shows a state before the main body portion 15 a of the holder 15 is press-fitted into the support hole 12 c of the casing 12.

As shown in FIG. 2A, the cross-sectional shape of the inner peripheral surface of the support hole 12c of the casing 12 is a perfect circle having a radius R. On the other hand, as shown in FIG. 2B, the cross-sectional shape of the outer peripheral surface of the main body 15a of the holder 15 before press-fitting is an ellipse having a major radius R1 and a minor radius R2. The relationship between the radius R of the perfect circle, the major radius R1 of the ellipse, and the minor radius R2 of the ellipse is
R2 <R <R1
And the radius R of the perfect circle is between the major radius R1 and minor radius R2 of the ellipse. In other words, when the cross-sectional shape of the inner peripheral surface of the support hole 12c and the cross-sectional shape of the outer peripheral surface of the holder 15 are overlapped with their centers aligned, the cross-section of the inner peripheral surface of the support hole 12c. This means that the shape extends over the inside and outside of the cross-sectional shape of the outer peripheral surface of the holder 15.

Further, the relationship between the circumference L of the perfect circle and the circumference L1 of the ellipse is L1 ≦ L in the first embodiment.
The circumference L of the perfect circle is set to be equal to or greater than the circumference L1 of the ellipse.

The relationship between the circumference L of the perfect circle and the circumference L1 of the ellipse is as follows: L <L1 in the second embodiment
The circumference L of the perfect circle is set smaller than the circumference L1 of the ellipse.

  Note that the difference between the ellipse major radius R1 and minor radius R2 of the main body 15a of the holder 15 is a slight difference of 0.1 mm or less, and is exaggerated in FIG.

  Next, the operation of the first and second embodiments of the present invention having the above configuration will be described.

  In FIG. 1, the ball 16 of the detent device 14 is biased by a spring 17 in a direction protruding from the opening of the holder 15, and the ball 16 is elastically applied to one notch of the fork shaft 11, for example, the notch 11b. By engaging, the fork shaft 11 is positioned in the axial direction. When the fork shaft 11 moves in the axial direction from this state, the ball 16 is pushed out from the notch 11b and is once pushed into the main body portion 15a of the sleeve 15 while compressing the spring 17, and then adjoined by the elastic force of the spring 17. The fork shaft 11 is positioned at a new position by re-engaging with the one notch 11a or the other notch 11c.

  Now, when the main body portion 15a of the holder 15 is press-fitted into the support hole 12c of the casing 12, the major radius R1 of the elliptical cross section of the main body portion 15a of the holder 15 is equal to the support hole 12c of the casing 12, as shown in FIG. Since the difference is larger than the radius R of the true circular cross section, the main body portion 15 a of the holder 15 is press-fitted into the support hole 12 c of the casing 12. During the press-fitting process, the major radius R1 of the main body portion 15a of the holder 15 is compressed until it coincides with the radius R of the support hole 12c of the casing 12, and accordingly, the minor radius R1 of the main body portion 15a of the holder 15 is reduced. It is expanded toward the radius R of the support hole 12c. However, in the first embodiment, the circumferential length L of the support hole 12c of the casing 12 is set to be larger than the circumferential length L1 of the main body portion 15a of the holder 15 even when the press-fitting completion shown in FIG. Therefore, the portion of the main body 15a of the holder 15 having the short radius R1 does not adhere to the inner peripheral surface of the support hole 12c of the casing 12, and a slight gap is maintained.

  FIG. 3 shows a tightening margin (horizontal axis) when press-fitting the main body portion 15a of the holder 15 into the support hole 12c of the casing 12, and surfaces of the press-fitting surfaces (the inner peripheral surface of the support hole 12c and the outer peripheral surface of the main body portion 15a). It is a graph which shows the relationship with pressure or stress (vertical axis), and the solid line is the first embodiment, and the relationship between the circumference L of the perfect circle and the circumference L1 of the ellipse is set to L1 ≦ L The broken line is the second embodiment and the relationship between the circumference L of the perfect circle and the circumference L1 of the ellipse is set to L <L1, and the chain line is a comparative example in which the support hole 12c of the casing 12 and This corresponds to a case in which the main body 15a of the holder 15 is a perfect circle. In addition, the strength limit is a limit at which a crack is generated in the support hole 12c portion of the aluminum-based casing 12 when the tightening allowance is further increased, and the removal limit is the casing 12 when the tightening allowance is reduced below that. This is a limit that the main body portion 15a of the holder 15 falls off from the support hole 12c.

  In the comparative example indicated by the chain line, since the perfect circle and the perfect circle are press-fitted, the surface pressure (stress) increases abruptly when the tightening margin is slightly large and exceeds the strength limit, and the tightening margin is slightly small. However, there is a problem that the surface pressure (stress) rapidly decreases and exceeds the removal limit, and the allowable range of the tightening margin becomes extremely narrow. Therefore, when the aluminum-based casing 12 having a large thermal expansion coefficient and the iron-based material holder 15 having a small thermal expansion coefficient are combined, the tightening allowance is only slightly changed due to a temperature change. There is a possibility that it will come off.

  On the other hand, in the first embodiment indicated by the solid line, the major radius portion of the main body portion 15a of the holder 15 comes into contact with the inner peripheral surface of the support hole 12c of the casing 12 and gradually collapses. The change in (stress) becomes gradual, and as a result, the allowable range of the interference is greatly expanded. Moreover, since the relationship between the circumferential length L of the perfect circle and the circumferential length L1 of the ellipse is set to L1 ≦ L, the support hole 12c of the casing 12 and the main body 15a of the holder 15 extend over the entire circumference even when the press-fitting is completed. Thus, it is possible to avoid a sudden increase in surface pressure (stress) and to secure a large allowable range of tightening allowance.

  Further, in the second embodiment indicated by a broken line, basically the same effect as that of the first embodiment can be obtained, but the relationship between the circumference L of the perfect circle and the circumference L1 of the ellipse is expressed as L. <Because it is set to L1, before the press-fitting is completed, the support hole 12c of the casing 12 and the main body 15a of the holder 15 are in close contact over the entire circumference (see point A in FIG. 3), and a comparative example therefrom. Similar to the above, the surface pressure (stress) rises rapidly. As a result, in the second embodiment, the allowable range of the tightening margin is slightly narrower than that of the first embodiment, but the allowable range of the tightening margin is greatly expanded as compared with the comparative example.

  Further, by making the cross-sectional shape of the inner peripheral surface of the support hole 12c of the casing 12 formed by drilling or the like a perfect circle, the processing can be facilitated, while the holder formed by drawing or the like Since the cross-sectional shape of the outer peripheral surface of 15 main-body parts 15a is made into an ellipse, processing man-hours and a processing cost hardly increase in order to make it an elliptical cross section.

Third embodiment

  Next, a third embodiment of the present invention will be described with reference to FIG.

  In the first and second embodiments, the cross-sectional shape of the inner peripheral surface of the support hole 12c of the casing 12 is a perfect circle, and the cross-sectional shape of the outer peripheral surface of the main body portion 15a of the holder 15 is an ellipse. In the embodiment, the cross-sectional shape of the inner peripheral surface of the support hole 12c of the casing 12 is an ellipse, and the cross-sectional shape of the outer peripheral surface of the main body portion 15a of the holder 15 is a triangular shape (a rice ball shape) with rounded corners. Then, when the cross-sectional shape of the inner peripheral surface of the support hole 12c and the cross-sectional shape of the outer peripheral surface of the holder 15 are overlapped with their centers being matched, the cross-sectional shape of the inner peripheral surface of the support hole 12c is the holder 15 It straddles the inner side and the outer side of the cross-sectional shape of the outer peripheral surface. Further, even if the relationship between the circumference L of the perfect circle and the triangle circumference L1 is set to L1 ≦ L as in the first embodiment, L <L1 as in the second embodiment. It may be set to.

  Also according to the third embodiment. The same effects as those of the first and second embodiments described above can be achieved.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, the cross-sectional shape of the inner peripheral surface of the support hole 12c of the casing 12 and the cross-sectional shape of the outer peripheral surface of the main body portion 15a of the holder 15 are not limited to the embodiment.

  In the first and second embodiments, the cross-sectional shape of the inner peripheral surface of the support hole 12c of the casing 12 is a perfect circle, and the cross-sectional shape of the outer peripheral surface of the main body 15a of the holder 15 is an elliptical shape. The relationship may be interchanged.

  Moreover, in 3rd Embodiment, although the cross-sectional shape of the inner peripheral surface of the support hole 12c of the casing 12 is made into an ellipse, and the cross-sectional shape of the outer peripheral surface of the main-body part 15a of the holder 15 is made into a rice cake shape, those relations are replaced. Also good.

  Further, the material of the casing 12 and the material of the holder 15 are not limited to the embodiment.

  In the embodiment, the detent device 14 is applied to an automobile transmission, but the application is arbitrary.

11 Fork shaft (shaft)
11a Notch 11b Notch 11c Notch 12 Casing 12c Support hole 15 Holder 16 Ball 17 Spring L Perimeter L1 Perimeter

Claims (3)

A support hole (12c) formed in the casing (12), a cylindrical holder (15) made of a different material from the casing (12) and press-fitted into the support hole (12c), and the holder (15 ) Movably accommodated in the ball (16), and a spring (17) accommodated in the holder (15) and biasing the ball (16),
The ball (16) is elastically brought into contact with a plurality of notches (11a to 11c) formed on the axially slidable shaft (11), so that the shaft (11) is moved to a plurality of stop positions. A detent device for positioning to either
When the cross-sectional shape of the inner peripheral surface of the support hole (12c) and the cross-sectional shape of the outer peripheral surface of the holder (15) are overlapped with their centers aligned, the cross-sectional shape of the inner peripheral surface is A detent apparatus straddling the inner side and the outer side of the cross-sectional shape of the outer peripheral surface.   The peripheral length (L) of the cross-sectional shape of the inner peripheral surface of the support hole (12c) is equal to or greater than the peripheral length (L1) of the cross-sectional shape of the outer peripheral surface of the holder (15). Detent device as described.   The casing (12) is made of an aluminum-based material, and the cross-sectional shape of the inner peripheral surface is a perfect circle, and the holder (15) is a ferrous material, and the cross-sectional shape of the outer peripheral surface is a non-circular shape. The detent apparatus according to claim 1, wherein the detent apparatus is characterized in that:

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