JPH0348442Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to automatic transmissions of automobiles, etc., and is intended to prevent oil leakage in the hydraulic check portion thereof.

In general, automatic transmissions are
A planetary gear type transmission mechanism configured to obtain different gears by selectively operating friction elements such as a torque converter, multiple clutches, and brakes, and hydraulic control for supplying and discharging hydraulic pressure to the friction elements. It consists of devices, etc., and each clutch,
Each brake is equipped with an engaging piston device, a servo device, etc., and is adapted to be engaged and released by supplying and discharging hydraulic pressure thereto. Therefore, in order to operate the automatic transmission normally, it is necessary to supply hydraulic pressure at a predetermined pressure to each element, and it is desirable to be able to check the hydraulic pressure from the outside. Therefore, conventionally, as shown in FIG. 1, a center support 2 that supports a brake 1 and a piston 9 for engaging the brake is press-fitted into a casing 3 and fixed, and a center support 2 is formed between the center support 2 and the piston 9. The oil chamber 4 for the hydraulic servo is communicated with the outside of the casing 3, and an oil pressure gauge (not shown) is attached thereto so that the oil pressure in the oil chamber 4 can be checked. That is, the casing 3 is formed with a threaded hole 3a through which the oil pressure gauge is screwed, and the center support 2 is provided with an oil passage 2 communicating with the threaded hole 3a.
A is formed in the screw hole 3a, and a check plug 5 is normally screwed into the screw hole 3a to seal it. However, during reverse operation, high pressure is applied to the brake 1, and the viscosity of the oil becomes low, especially at high temperatures.In the conventional structure, oil leaks from the gap between the center support 2 and the press-fitted part of the casing 3. Furthermore, there was a problem in that the pressure drop led to brake burnout.

This idea was created in view of the above problems.
The purpose is to prevent oil leakage between the center support and the casing in the hydraulic check section. To achieve this purpose, the structure of the oil leak prevention structure in the hydraulic check section of the present invention includes a casing, a center support that is press-fitted into the inside of the casing and serves to support the friction elements and the engagement piston, and a screw hole formed in the press-fitted part of the center support of the casing to which a hydraulic pressure gauge or a check plug can be attached; an oil chamber for a hydraulic servo disposed inside the center support and used to drive the engagement piston; In an automatic transmission equipped with an oil passage communicating between the oil chamber and the screw hole, an O-ring is attached to the outer periphery of the oil passage surrounding the casing side opening of the center support. Features.

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 2 is a sectional view of the first embodiment of the present invention. In the figure, the casing 3 is similar to the conventional case.
A screw hole 3a for screwing an oil pressure gauge is formed through the center support 2, and an oil passage 2a is formed in the center support 2 to communicate the oil chamber 4 inside the center support 2 with the screw hole 3a of the casing 3. Here, the opening of the oil passage 2a on the casing 2 side has a smaller diameter than the screw hole 3a and is located at the center of the screw hole 3a. On the other hand, a stepped portion 5a is formed at the tip of the check plug 5 that is screwed into the screw hole 3a, and an O-ring 6 is attached thereto, so that when the check plug 5 is screwed into the screw hole 3a, the O-ring 6 is It surrounds and is located on the outer periphery of the opening of the oil passage 2a on the casing 3 side and is pressed by the check plug 5 to prevent oil from the oil passage 2a from leaking into the press-fitted part between the center support 2 and the casing 3. . Note that 7 is an O-ring for preventing oil from leaking between the casing 3 and the check plug 5, but it can be omitted in this embodiment.

Next, a second embodiment of the present invention will be described.
FIG. 3 shows a cross-sectional view of a second embodiment of the present invention. In this embodiment, a screw hole 3a is formed in the casing 3, and the center support 2 has an oil passageway communicating with an internal oil chamber 4. In addition to forming a passage 2a, an oil passage 2a and a screw hole 3a are formed on the outer surface of the center support 2.
forms an O-ring mounting hole 2b located inside the O-ring mounting hole 2b. Then, an O-ring 8 having a wire diameter equal to or smaller than the depth of this O-ring mounting hole 2b and an outer diameter approximately equal to the hole diameter is inserted into the O-ring mounting hole 2b, and the center support 2 and casing 3 are connected. By fitting, the O-ring 8 is held in the O-ring mounting hole 2b, and the O-ring 8 is mounted around the opening of the oil passage 2a on the casing 3 side surrounding the opening thereof. In this way, as shown in FIG. 4, when hydraulic pressure is applied, the O-ring 8 extends in the outer circumferential direction due to the pressure difference and is pressed against the joint between the center support 2 and the casing 3. This prevents oil from leaking between the holes. In addition, since the wire diameter of the O-ring 8 is equal to or smaller than the depth of the O-ring mounting hole 2b, the center support 2
The O-ring 8 will not be cut by the casing 3 when the casing 3 and the casing 3 are assembled together.

As specifically explained above with reference to the embodiments, the present invention has an O-ring that blocks the gap between the mating surface of the center support and the casing and the oil passage, so that no hydraulic pressure is applied to the oil chamber. Even when oil is supplied, oil does not leak from this mating surface, making it possible to control the hydraulic servo with extremely high precision, and preventing accidents such as brake burnout due to pressure drop.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the hydraulic check section of a conventional automatic transmission, Figs. 2 to 4 relate to embodiments of the present invention, and Fig.
FIG. 3 is a sectional view of a second embodiment of the present invention, and FIG. 4 is a partially enlarged sectional view thereof. In the drawing, 1 is the brake, 2 is the center support,
2a is an oil path, 3 is a casing, 3a is a screw hole, 4
is an oil chamber, 5 is a check plug, 6, 7, 8 are O-rings, and 9 is a piston.

Claims (1)

[Scope of utility model registration request] a casing; a center support press-fitted into the inner side of the casing to support the friction element and the engagement piston; and a threaded hole formed in the center support press-fitted part of the casing to which a hydraulic pressure gauge or check plug can be attached. , an automatic transmission comprising an oil chamber for a hydraulic servo disposed inside the center support and used to drive the engagement piston, and an oil passage communicating the oil chamber with the screw hole. An oil leak prevention structure in a hydraulic check section, characterized in that an O-ring is attached to the outer periphery of the opening of the oil passage of the center support on the casing side.