JPH0656554U - Bearing support structure for transmission case - Google Patents

Abstract

(57) [Abstract] [Purpose] In a transmission equipped with a transmission case made of aluminum die-cast, bearing fitting due to creep wear or thermal expansion difference in the fitting hole with the outer circumference of the transmission case bearing due to gear meshing reaction force, vibration, etc. Prevents loosening of parts and prevents accidents. [Structure] A high-strength aluminum alloy bearing case is fitted between the outer circumference of the bearing that supports the main shaft, counter shaft, etc. and the fitting hole of the transmission case, and creep wear occurs in the fitting hole with the outer circumference of the bearing. And prevent loosening of the bearing fitting part due to thermal expansion difference.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a structure of a bearing support portion of an aluminum alloy die-cast transmission case in a transmission used for automobiles, various vehicles, construction machinery and the like.

[0002]

[Prior art]

 FIG. 3 shows a main structure of a conventional automobile transmission. In the figure, 1 is a transmission case, 2 is a main shaft, 3 is a drive shaft to which rotational force from an engine is input, 4 is a counter shaft for speed, 5 is a drive gear fixed to the drive shaft 3, and 6 is a drive gear. A gear group for speed change, 7 is a roller bearing that supports the drive shaft 3 and the main shaft 2, and 8 is a roller bearing that supports the counter shaft 4.

In such a transmission, the transmission case 1 is usually manufactured by aluminum alloy die casting, and the roller bearings 7 and 8 for the drive shaft and the main shaft and the counter shaft are fitted into the transmission case 1. It is press-fitted into the holes 9 and 10.

[0004]

[Problems to be solved by the device]

 In such a transmission, the reaction force of the meshing force of the gears when transmitting the rotational force from the engine acts on the bearings (roller bearings 7, 8) that support the gear shafts such as the main shaft 2 and the counter shaft 4. The bearings 7 and 8 are further subjected to the reaction force by the vibration generated on the gear shaft.

In the conventional transmission shown in FIG. 3, the bearings 7 and 8 are directly press-fitted into the fitting holes 9 and 10 of the aluminum die-cast transmission 1 having a relatively low hardness. The vibration may cause creep wear on the inner surfaces of the fitting holes 9 and 10 which are in pressure contact with the outer peripheral surfaces of the bearings 7 and 8, and the transmission may be damaged due to looseness of the bearing fitting portions.

In order to solve such a problem, a means for casting a bush-shaped annular support made of cast iron material into the fitting holes 9 and 10 is also provided, but the aluminum alloy material of the transmission case and the annular support are provided. Since the coefficient of thermal expansion differs greatly from that of the cast iron material of the body, the temperature rise during operation may cause looseness in the fitting part due to the difference in thermal expansion, and the same accident as above may occur.

It is an object of the present invention to provide a transmission having great durability by preventing the occurrence of slack due to creep wear or difference in thermal expansion of the bearing fitting portion.

[0008]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a high bearing between the outer circumference of a roller bearing such as a main shaft and a counter shaft that supports a gear shaft, a rolling bearing such as a ball bearing, and a fitting hole formed in a transmission case. It is made of aluminum alloy (JIS.AC4A-T6 material, AC9A-T6 material, etc.), and is fitted with an annular support body that supports the bearing on the inner peripheral side, and also on the outer peripheral side of the annular support body or the transmission case. It is characterized in that a rotation preventing means is provided between the support and the support. In this case, the detent means may be formed by splines, teeth or polygons on the outer peripheral side of the bush-shaped annular support, or may be fixed by pinning or plasma welding as described later. If necessary, a guide may be provided on the support fitting side. Further, as the fitting means, it is preferable to use a means such as plasma welding in addition to the press-fitting so as to ensure the fixation with the transmission case.

[0009]

[Action]

 According to this technical means, the reaction bearing and the vibration due to the meshing of the gears act on the bearing of the transmission during the operation of the engine, but the fitting hole to be fitted on the outer peripheral surface of the bearing is made of hard high-strength aluminum alloy. Since it is provided on the annular support, the wear resistance of the fitting hole is improved, and the occurrence of creep wear is prevented.

Since the annular support is made of a high-strength aluminum alloy, the coefficient of thermal expansion is substantially the same as that of the aluminum die-cast transmission case, and there is no difference in thermal expansion between the two. No slack will occur between the annular support and the transmission outer peripheral fitting hole due to heat. Moreover, since the rotation-stopping means is provided on the outer peripheral side of the annular support, it does not run idle between the fitting hole of the transmission case.

[0011]

【Example】

 Hereinafter, embodiments of the present invention will be illustratively described in detail with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention to them, but are simple. It is only an example. 1 is a schematic perspective view showing a main part of the transmission, and FIG. 2 is a sectional view taken along the line II-II in FIG.

In the figure, 1 is a transmission case, 2 is a main shaft which is an output shaft, 3 is a drive shaft to which power from an engine (not shown) is input, and 5 is a drive fixed to the drive shaft 3. A gear 6 is a gear group for shifting.

Reference numeral 7 denotes a roller bearing that supports the drive shaft 3 and the main shaft 2, and two roller bearings are provided on the drive shaft 3 side (input side) and the output side (not shown). Reference numeral 8 denotes a roller bearing that supports the counter shaft 4, and two roller bearings are provided at the shaft end of the counter shaft 4. The above construction is similar to the conventional one shown in FIG. 3, and the same members are designated by the same reference numerals.

The roller bearings 7 and 8 are mounted by press-fitting their outer peripheral surfaces into the fitting holes 109 and 110 of the annular supports 11 and 12, respectively. According to JIS. It is made of high-strength aluminum alloy material such as standard AC4A-T6 material, AC9A-T6 material, etc., and outer circumferences of these are formed with tooth-shaped or spline-shaped detent means 11a, 12a. 2 is press-fitted into the transmission case 1a and integrally fixed. If necessary, the annular supports 11 and 12 may be retained in the axial direction by retainers 13 and 14 as shown in FIG.

In the transmission configured as described above, when the engine is operated, its power (rotational force) is input from the drive shaft 3 to the transmission. The rotation of the drive shaft 3 enters the gear group in the transmission from the drive gear 5, is shifted at a gear ratio set by a synchronizing mechanism (not shown), and is output to the axle side via the counter shaft 4 and the main shaft 2. To be done.

At this time, the roller bearings 7 and 8 are subjected to a radial load including a gear meshing reaction force and, in addition, a variation due to vibration generated in the gear group and the shaft system. In the present invention, the outer peripheral surfaces of the roller bearings 7 and 8 are fitted into the fitting holes 109 and 110 of the annular supports 11 and 12 made of a high-strength aluminum alloy having a hardness higher than that of the aluminum alloy die-cast transmission case 1. Since they are press-fitted, the amount of creep wear due to the radial load on the inner surfaces of the fitting holes 109 and 110 is greatly reduced as compared with the conventional one as shown in FIG.

Further, since the annular supports 11 and 12 are made of a high-strength aluminum alloy of the same type as the aluminum alloy die-cast transmission case 1, the thermal expansion coefficients of the both are substantially the same, so that the transmission temperature is Even if it rises, there is no difference in the amount of thermal expansion between the annular supports 11 and 12 and the transmission case 1, and the bearings 11 and 12 are not loosened due to this.

In the above embodiments, the annular supports 11 and 12 are press-fitted through the splines 11a and 12a on the outer peripheral side to be attached to the transmission case 1. It is within the scope of the present invention to adopt a system. (A) The outer peripheral surfaces of the annular supports 11 and 12 are cylindrical surfaces and are press-fitted into the fitting holes of the transmission case 1, and are circumferentially locked by a pin or the like. (B) The outer circumferences of the annular supports 11 and 12 and the fitting hole of the transmission case 1 are formed in a polygonal shape such as a hexagonal shape or an octagonal shape so as to be fitted also as a rotation stop. (C) The oxide films on the outer circumferences of the high-strength aluminum alloy annular supports 11 and 12 are removed and fixed to the transmission case 1 by plasma welding.

The present invention also includes the case where various rolling bearings such as ball bearings and needle bearings are used in place of the roller bearings 7 and 8.

[0020]

[Effect of device]

 The present invention is configured as described above, and according to the present invention, since the outer peripheral surface of the bearing is fitted to the annular support made of high-strength and high-strength aluminum alloy, the creep wear in the fitting portion is prevented. It is possible to suppress the occurrence of slack and the occurrence of slack in the outer peripheral portion of the bearing.

Further, since the annular support is made of a high-strength aluminum alloy similar to the transmission case, there is no difference in thermal expansion between the two and the occurrence of slack in the bearing outer peripheral fitting portion is suppressed. As a result, the occurrence of accidents in the bearing can be prevented and the durability of the transmission can be improved. It has various remarkable effects.

[Brief description of drawings]

FIG. 1 is an external perspective view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a response diagram of FIG. 1 showing a conventional example.

[Explanation of symbols]

 1 Transmission Case 2 Main Shaft 3 Drive Shaft 4 Counter Shaft 7 Roller Bearing 8 Roller Bearing 11 Ring Support 12 Ring Support 109 Fitting Hole 110 Fitting Hole

Claims (1)

[Scope of utility model registration request] 1. A transmission provided with a transmission case manufactured by aluminum die casting, wherein a roller bearing for supporting a gear shaft such as a main shaft and a counter shaft, a roller bearing such as a ball bearing, and a transmission case are drilled. The high-strength aluminum alloy (J
IS. AC4A-T6 material, AC9A-T6 material, etc.), and an annular support body that supports the bearing on the inner peripheral side is fitted and a rotation stop is provided between the outer peripheral side of the annular support body or between the transmission case and the support body. A bearing support structure for a transmission case, characterized in that means are provided.