JPH056250U - Transmission - Google Patents

Abstract

(57) [Abstract] [Purpose] Providing a transmission capable of applying an appropriate preload to the taper roller bearing both during cold and hot conditions. [Structure] 12 is a thrust washer and a transmission case It is interposed between the bearing holder portion 11 on the second side and the tapered roller bearing 9. The thrust washer 12 is made of a shape memory alloy and has a flat shape when cold and a tapered shape when hot.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a transmission for an automobile or the like, and more particularly to a technique for applying an appropriate preload to a tapered roller bearing.

[0002]

[Prior Art]

 In an automobile transmission, a plurality of gear shafts are rotatably supported in a transmission case via bearings. What is shown in FIG. 3 is a so-called FF type passenger car manual transmission, and the rear surface of the clutch housing 1 also serves as the wall surface of the transmission case 2. Among the gear shafts, an input shaft 3 and an intermediate shaft 4 connected to an engine and a clutch (not shown) are supported by the clutch housing 1 and the transmission case 2 through ball bearings 5, but are connected to the differential gear 6. The output shaft 7 is supported by a pair of taper roller bearings 8 and 9 so as to support thrust in the thrust direction. The taper roller bearings 8 and 9 are fitted in bearing holder portions 10 and 11 formed in the clutch housing 1 and the transmission case 2, respectively, and are also interposed between the bearing holder portions 11 on the transmission case 2 side. The thrust is applied by a thrust washer (shim) 12.

[0003]

[Problems to be solved by the device]

 As is well known, when using a tapered roller bearing, it is indispensable to apply an appropriate preload to prevent rattling and to prolong the life of the bearing. ing. However, in transmissions in recent years, the gear shafts including the output shaft 7 are made of steel, while the clutch housing 1 and the transmission case 2 are often made of aluminum alloy. The value of was often different. That is, since the aluminum alloy has a higher coefficient of thermal expansion than steel, the distance between the bearing holders 10 and 11 increases with the length of the output shaft 7 as the transmission temperature rises. Therefore, as shown in FIG. 4 (enlarged view of portion A in FIG. 3), when the proper preload is applied during cold, the taper roller bearings 8 and 9 are disengaged during hot (in the figure, (indicated by c)), the life is significantly shortened, and if an appropriate preload is applied during hot conditions, the preload during cold conditions becomes excessive and the rotational resistance increases, resulting in the deterioration of fuel efficiency. Of.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transmission capable of applying an appropriate preload to a taper roller bearing both during cold and hot conditions.

[0005]

[Means for Solving the Problems]

 Therefore, in order to solve this problem, in the present invention, in a transmission in which a gear shaft is held through a pair of left and right tapered roller bearings fitted in a bearing holder portion of a transmission case, the bearing holder portion and the taper portion are tapered. A thrust washer made of a shape memory alloy was inserted between the end of the roller bearing and the roller washer.

[0006]

[Action]

 The difference between the displacement of the gear shaft length and the displacement of the transmission case due to the difference in the coefficient of thermal expansion is offset by the deformation of the thrust washer, and the taper roller bearing is properly preloaded in both cold and hot conditions. Given.

[0007]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the description of the embodiments, the same members as the above-mentioned conventional members are designated by the same reference numerals, and duplicate explanations are omitted.

FIG. 1 shows an embodiment of a transmission according to the present invention in cross section, and FIG. 2 shows a perspective view of a single thrust washer. In FIG. 1, reference numeral 12 denotes a thrust washer, which is interposed between the bearing holder portion 11 on the transmission case 2 side and the taper roller bearing 9 as in the conventional case. The thrust washer 12 is made of a shape memory alloy and, as shown in FIG. 2, is formed so as to have a flat shape in the cold state and a taper shape in the hot state (80 ° C. or higher in this embodiment). Has been done.

The operation of this embodiment will be described below. When the engine is started and put into operation, the transmission temperature gradually rises due to meshing friction between the gear shafts 3, 4, 7 and agitation of gear oil. Then, due to the difference in the coefficient of thermal expansion, the distance between the bearing holders 10 and 11 is larger than the length of the output shaft 6. However, in this embodiment, as described above, the thrust washer 12 has a taper shape when hot, so that there is no rattling between the bearing holder portion 11 and the taper roller bearing 9, and an appropriate preload is obtained. It is given to the tapered roller bearings 8 and 9. As a result, in this embodiment, the life of the tapered roller bearings 8 and 9 is much longer than that of the conventional one. On the other hand, when the engine stops and the temperature inside the transmission drops, the length of the output shaft 6 and the distance between the bearing holders 10 and 11 return to their original state, but the thrust washer 12 also becomes flat and restarts. Moreover, excessive preload is prevented from acting on the taper roller bearings 8 and 9.

Although the specific example is finished as described above, the aspect of the present invention is not limited to this example. For example, in the above embodiment, the flat thrust washer 12 is configured to change into a taper shape due to the temperature rise, but it may be formed into a cylindrical shape and only the length in the axial direction may be changed. Further, the thrust washer 12 may be interposed in both bearing holders 10 and 11.

[0011]

[Effect of the device]

 According to the transmission of the present invention, between the bearing holder portion of the transmission case and the taper roller bearing that holds the gear shaft, deformation occurs such that the thickness in the hot state is larger than the thickness in the cold state. Since the thrust washer made of shape memory alloy is interposed, it is possible to exert an appropriate preload on the tapered roller bearing both during cold and hot conditions.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part showing the operation of a transmission according to the present invention.

FIG. 2 is a perspective view showing a deformed state of the thrust washer.

FIG. 3 is a vertical cross-sectional view showing the entire transmission.

FIG. 4 is an enlarged view of part A in FIG.

[Explanation of symbols]

 1 Clutch housing 2 Transmission case 7 Output shaft 8,9 Tapered roller bearing 10,11 Bearing holder part 12 Thrust washer

Claims (1)

Claims for utility model registration 1. A transmission comprising a pair of taper roller bearings fitted in a bearing holder of a transmission case for holding a gear shaft, the bearing holder and the taper roller. A transmission, characterized in that a thrust washer made of a shape memory alloy is interposed between the end of the bearing and the end portion of the bearing so that the thickness when hot is greater than the thickness when hot.