JP2017072176A - Gear transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a needle roller bearing which is incorporated between a rotating shaft of a manual transmission and a constantly-engaged gear is high in a part cost.SOLUTION: This gear transmission device comprises: a rotating shaft 10; a cylindrical slide bearing 50 which is fit to the rotating shaft 10; a planetary gear 862 which is rotatably fit to the rotating shaft 10 via a clearance between an external peripheral face of the slide bearing 50 and itself; a stopper 40 which is arranged at the rotating shaft 10, and has an abutment face 42 which abuts on one end face of the slide bearing 50; and a pressure-fit member 60 which is pressure-fit to the rotating shaft 10, and has an abutment face 62 which abuts on the other end face of the slide bearing 50. At least either of one end face and the other end face of the slide bearing 50 includes a head-cut conical face 52 continuous to an external peripheral side, and the abutment face 62 which abuts on at least either of one end face and the other end face of the slide bearing 50 out of the abutment face 42 of the stopper 40 and the abutment face 62 of the pressure-insertion member 60 is formed into a head-cut conical shape having a complementary property with respect to the head-cut conical face 52 of the slide bearing 50.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gear transmission provided with an idler gear mounted on a rotary shaft so as to be relatively rotatable via a cylindrical slide bearing.

  In a vehicle manual transmission incorporating a constant meshing gear, the constant meshing gear other than the constant meshing gear that achieves the selected gear position is a needle roller bearing or the like with respect to a rotation shaft such as a transmission output shaft. It is supported so as to be relatively rotatable via a bearing member. Such a gear transmission is well known in Patent Document 1 and the like.

Utility Model Registration No. 2548901

  In order to reduce the parts cost and manufacturing cost of the vehicle manual transmission incorporating the above-described constant meshing gear, it may be possible to incorporate a plain bearing between the rotary shaft and the constant meshing gear instead of the needle roller bearing. ing.

  On the other hand, as a gear incorporated in a vehicle manual transmission, a helical gear having a large torque transmission force and a low noise is generally used. However, as is well known, the helical gear also generates a thrust force at the same time as it rotates, so that the helical gear itself is urged in the axial direction as it rotates. More specifically, if this is a constant meshing gear, its rotational axis tends to be inclined with respect to the rotational axis of the rotational shaft that supports it. For this reason, when a slide bearing is incorporated between the rotating shaft and the constant meshing gear instead of the needle roller bearing described above, the surface pressure between the end of the plain bearing on the side where the constant meshing gear is inclined and the constant meshing gear. May increase, and seizure may occur as the oil runs out.

  In order to avoid such problems, it is possible to suppress an increase in surface pressure with the sliding bearing when the meshing gear is always inclined by processing the outer peripheral surface of the sliding bearing into a center-convex barrel shape. . However, when processing the outer peripheral surface of a plain bearing into a barrel shape, high processing accuracy is required, so the manufacturing cost increases, and there is a large difference in cost compared to the case of using a needle roller bearing. It will disappear.

  An object of the present invention is to provide an idler gear that is mounted on a rotary shaft so as to be relatively rotatable via a cylindrical slide bearing, and the same durability can be obtained without using an expensive needle roller bearing. The object is to provide a gear transmission.

  A gear transmission according to the present invention includes a rotary shaft, a cylindrical slide bearing fitted to the rotary shaft, an idle gear that is rotatably fitted to the rotary shaft via the slide bearing, and the rotation A stopper provided on a shaft and having a contact surface that comes into contact with one end surface of the slide bearing; and a press-fit member having a contact surface that is press-fitted into the rotary shaft and comes into contact with the other end surface of the slide bearing. A gear transmission, wherein at least one of the one end surface and the other end surface of the plain bearing includes a truncated conical surface continuing to the outer periphery thereof, the contact surface of the stopper and the contact surface of the press-fitting member The abutting surface that abuts at least one of the one end surface and the other end surface of the sliding bearing is a frustoconical surface that is complementary to the frustoconical surface of the sliding bearing. It is what.

  In the present invention, when the press-fitting member is press-fitted into the rotating shaft so that the slide bearing is compressed between the press-fitting member and the stopper, the contact between the frustoconical surface of the contact surface and the frustoconical surface of the slide bearing. Due to the component force, the slide bearing is bent into a middle convex barrel shape. Therefore, the gap between the outer peripheral surface of the slide bearing and the inner peripheral surface of the idle gear is larger at both ends of the slide bearing than the intermediate portion thereof.

  According to the gear transmission of the present invention, the sliding bearing can be maintained in a state of being elastically deformed into a middle convex barrel shape, so that the gap between the both ends of the sliding bearing and the idle gear is the intermediate portion in the longitudinal direction of the sliding bearing. And the clearance between the idle gear and the idle gear can be increased. For this reason, even if the rotation axis of the idle gear tilts during rotation, it is possible to suppress an increase in contact pressure between the end of the slide bearing and the idle gear, and to avoid problems such as seizure. . Further, since the slide bearing can be easily and reliably elastically deformed into a barrel shape, there is no need to manufacture such a middle convex barrel-shaped slide bearing by machining. As a result, it is possible to employ a low-cost cylindrical plain bearing instead of an expensive needle roller bearing in a gear transmission having an idler gear that is mounted so as to be rotatable relative to the rotating shaft, and is durable. A gear transmission with good performance can be obtained at low cost.

It is sectional drawing showing the schematic structure of one Embodiment of the gear transmission by this invention. FIG. 2 is a sectional view in which a contact portion between a pressure gear and a second bearing bush in FIG. 1 is extracted and enlarged, and a lower half of the figure shows a state before the pressure gear is pressed against the second bearing bush. It is a graph showing the relationship between the cone angle and the amount of deflection of the bearing bush when the press-fit load is constant.

  An embodiment in which a gear transmission according to the present invention is applied to a manual transmission will be described in detail with reference to FIGS. However, the present invention is not limited to such an embodiment, but can be applied to any gear transmission having an idler gear that is fitted to a rotary shaft so as to be relatively rotatable via a slide bearing.

  FIG. 1 schematically shows a cross-sectional structure in which a part of the manual transmission according to the present invention is extracted and enlarged, and FIG. 2 shows a part of the manual transmission extracted and enlarged, but the elastic deformation of the bearing bush is exaggerated. ing. A transmission output shaft (hereinafter simply referred to as an output shaft) 10 as a rotating shaft in the present invention in which an oil passage 10a is formed is a hollow stepped shaft having a step portion 11, but is not limited thereto. Not. A washer 20, a first bearing bush 30, a hub 40, and a second bearing bush 50 are attached to an intermediate portion of the output shaft 10 in order from the side closer to the stepped portion 11. The spline 12 is formed at the end of the intermediate portion of the output shaft 10, and the press-fitted gear 60 is spline-fitted with a predetermined press-fit load, and the press-fitted gear 60 is integrally fixed to the output shaft 10. It has become.

  Accordingly, the annular washer 20 is sandwiched between the step portion 11 of the output shaft 10 and the cylindrical first bearing bush 30 that rotatably supports the first constant meshing gear 70. It has become. An annular hub 40 as a stopper in the present invention together with the washer 20 is between the first bearing bush 30 and a cylindrical second bearing bush 50 that rotatably supports the second constant meshing gear 80. It is in a state sandwiched between. The first bearing bush 30 and the second bearing bush 50 as a slide bearing in the present invention are sandwiched between the hub 40 and a press-fit gear 60 as a press-fit member in the present invention.

  The press-fitted gear 60 and the constantly meshing gears 70 and 80 mesh with corresponding synchronous gears 61, 71 and 81 attached to a driven shaft (not shown). A well-known synchromesh mechanism (not shown) or the like is arranged between two constant meshing gears 70 and 80 adjacent to each other with the hub 40 interposed therebetween, so that one of the regular meshing gears 70 and 80 is integrated with the output shaft 10. So that a desired gear stage is achieved.

  The press-fitting load of the press-fitting gear 60 with respect to the output shaft 10 is such that the first and second bearing bushes 30 and 50 receive a compression along the axial direction (left-right direction in FIG. 1) and have a desired convex amount δ. It is set to elastically deform into a barrel shape. For this reason, the first and second bearing bushes 30 and 50 are attached to the output shaft 10 in an intermediate fit or an interference fit, but the present invention is not limited to this. On the outer peripheral surfaces of these bearing bushes 30 and 50, a plurality of oil grooves 31 and 51 extending in parallel with each other from one end surface to the other end surface are provided in the circumferential direction of these bearing bushes 30 and 50, respectively. It is formed at regular intervals. The oil passage 10a of the output shaft 10 and a part of the oil grooves 31, 51 of the bearing bushes 30 and 50 are connected via communication passages 10b, 30a and 50a formed in the output shaft 10 and the bearing bushes 30 and 50. Yes. As a result, the pressure oil flowing through the oil passage 10a is guided to the oil grooves 31, 51 via the communication passages 10b, 30a, 50a, and the simultaneous meshing gears 70, 80, the bearing bushes 30, 50, the press-fitting gear 60, and the hub 40. , Lubrication with the washer 20 is performed smoothly. As a result, the simultaneous meshing gears 70 and 80 can be prevented from being seized between the bearing bushes 30 and 50, the hub 40, the press-fitted gear 60, and the washer 20.

  The constant mesh gears 70, 80 are always connected to the bearing bushes 30, 50 between the inner peripheral surfaces of the center holes 70 a, 80 a formed in the constant mesh gears 70, 80 and the outer peripheral surfaces of the bearing bushes 30, 50. An appropriate annular gap is formed so as to be rotatable.

  One end surfaces of the bearing bushes 30 and 50 facing the press-fitting gear 60 side in the present embodiment include truncated conical surfaces 32 and 52, respectively, following the outer peripheral side thereof. The apex angle α of the truncated conical surfaces 32 and 52 is preferably about 140 to 160 degrees, but is not limited thereto. The press-fit gear 60 that abuts on one end surface of the bearing bushes 30 and 50 and the abutment surfaces 62 and 42 of the hub 40 are complementary to the truncated conical surfaces 32 and 52 formed on the bearing bushes 30 and 50. Although it is a frustoconical surface, it does not have to be exactly the same apex angle α as the apex angle α of the frustoconical surfaces 32, 52 of the bearing bushes 30, 50. In short, when the press-fitting gear 60 is press-fitted into the spline 12 of the output shaft 10 with a predetermined press-fitting load, the truncated conical surface 61 of the press-fitted gear 60 abuts against the truncated conical surface 52 of the bearing bush 50 and the bearing bush 30 , 50 need only be elastically deformed from the state shown in the lower half of FIG. 2 to the middle convex barrel shape shown in the upper half.

  Here, FIG. 3 shows the relationship between the apex angle of the truncated conical surfaces 32 and 52 and the amount of deflection of the bearing bushes 30 and 50 when the press-fitting load of the press-fitting gear 60 to the output shaft 10 is set constant. As is apparent from FIG. 3, it will be understood that there is a correlation between the apex angle of the truncated conical surfaces 32 and 52 and the amount of deflection of the bearing bushes 30 and 50. Accordingly, by appropriately setting the press-fitting load and the apex angles of the truncated conical surfaces 32 and 52, the radial deflection δ of the bearing bushes 30 and 50 can be defined to a desired value.

  In this way, the bearing bushes 30 and 50 are elastically deformed into a center-convex barrel shape, respectively, so that the longitudinal ends (left and right directions in FIG. 1) of the bearing bushes 30 and 50 and the constantly meshing gears 70 and 80 are always connected. A gap extending like a wedge can be formed therebetween. As described above, the constant meshing gears 70 and 80 formed by the helical gears together with the synchronous gears 71 and 81 are always in mesh with the synchronous gears 71 and 81. For this reason, the constant meshing gears 70, 80 receive the thrust force simultaneously with the rotational force from the synchronous gears 71, 81 and are displaced in the axial direction of the output shaft 10. Inclined with respect to the rotation axis, the end portions of the center holes 70a, 80a of the meshing gears 70, 80 are always closer to the outer peripheral surfaces of the bearing bushes 30, 50. However, since the bearing bushes 30 and 50 are formed in a middle convex barrel shape, an increase in the surface pressure between the end portions of the bearing bushes 30 and 50 and the constantly meshing gears 70 and 80 can be avoided. It is possible to prevent the occurrence of seizure between the two.

  In the embodiment described above, the truncated conical surfaces 32 and 52 are formed only on one end surface side of the bearing bushes 30 and 50, but these truncated conical surfaces 32 and 52 are also formed on the other end surfaces of the bearing bushes 30 and 50. Is possible. In this case, it goes without saying that a complementary frustoconical surface must also be formed in the portion of the hub 40 and the washer 20 that abuts against the other end surfaces of the bearing bushes 30 and 50. Alternatively, the truncated conical surface may be formed only on the other end surface side of the bearing bushes 30 and 50. In either case, the bearing bushes 30 and 50 can be elastically deformed into a middle-convex barrel shape by attaching the press-fitting gear 60 to the output shaft 10 with a predetermined press-fitting load.

  It should be noted that the present invention should be construed only from the matters described in the claims, and in the above-described embodiment, all the changes and modifications included in the concept of the present invention are other than those described. Is possible. That is, all matters in the above-described embodiments are not intended to limit the present invention, and can be arbitrarily changed according to its use, purpose, and the like, including configurations not directly related to the present invention. Is.

DESCRIPTION OF SYMBOLS 10 Transmission output shaft 40 Hub 42 Abutting surface 50 2nd bearing bush 52 Cone conical surface 60 Press-fit gear 62 Abutting surface 80 2nd constant meshing gear

Claims (1)

A rotation axis;
A cylindrical plain bearing fitted to the rotating shaft;
An idler gear that is rotatably fitted to the rotary shaft through a gap between the outer peripheral surface of the slide bearing,
A stopper provided on the rotating shaft and having an abutting surface that abuts on one end surface of the plain bearing;
A gear transmission comprising a press-fit member press-fitted to the rotary shaft and having a contact surface that contacts the other end surface of the slide bearing,
At least one of the one end surface and the other end surface of the slide bearing includes a truncated conical surface continuing to the outer peripheral side,
Of the contact surface of the stopper and the contact surface of the press-fitting member, the contact surface that contacts at least one of the one end surface and the other end surface of the slide bearing is in relation to the frustoconical surface of the slide bearing. The gear transmission is a truncated conical surface having complementary properties.

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