JPS6147329B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an automatic transmission equipped with a device for removing hydraulic fluid in a transmission clutch. Before starting the description of the device according to the invention, the conventional device and its drawbacks will be explained. An automatic transmission for an automobile is a device that converts the output of the engine into a desired gear ratio using a torque converter and a planetary gear train and transmits it to the propulsion shaft. In order to select a suitable value, a clutch, brake, one-way clutch, etc. are operated in an appropriate combination. FIG. 1 schematically shows only the upper half of the structure of a known automatic transmission with three forward speeds and one reverse speed, using a skeleton diagram. Two clutches (front clutch 1,
Rear clutch 2), two planetary gears 3, 4, band brake 5, brake 6 and one-way clutch 7
These actions cause the input shaft 8 to
It transmits power from the output shaft 9 to the output shaft 9. By operating each element as shown in the table below, a predetermined gear ratio of 3 forward speeds and 1 reverse speed can be obtained.
The details of these configurations and operations are well known and have no direct relation to the purpose of the present invention, so a description thereof will be omitted.

[Table] As shown in the table above (○ indicates that they are operating), in the neutral position, all clutches and brake elements are in a released state with no hydraulic pressure acting on them, and no output is output from the input shaft 8. No rotational force is transmitted to the shaft 9. In this case, the input shaft 8, which receives rotational force from the engine, is always rotating, and the drum 10 of the rear clutch 2 connected thereto is also rotating.
This rotation causes problems as described below, which will be explained based on FIGS. 2 and 3. FIG. 2 mainly shows a front clutch 1 and a rear clutch 2 of the automatic transmission schematically shown in FIG.
FIG. An oil pump 13 having an oil pump cover 11 and an oil pump housing 12 is fixed to a case 14 with bolts 15. The input shaft 8 rotatably supported on the inner diameter part of the oil pump cover 11 is
The left end is connected to a torque converter (not shown), and the right end is connected to the drum 10 of the rear clutch 2 by a spline so that it can rotate together with the drum 10 of the rear clutch 2. A piston 18 pressed against the bottom by a return spring 17 is disposed in the cylinder portion of the rear clutch drum 10, and a plurality of driven plates 19 are arranged on the right side of the piston 18 so as to be engaged when the piston 18 is actuated by hydraulic pressure. and a plurality of drive plates 20 are arranged. The driven plate 19 is spline-coupled to the inner diameter of the rear clutch drum 10 at its outer periphery so as to be movable in the axial direction, while the drive plate 20 is connected to the member 21 by a spline provided on its inner diameter. They are engaged so as to be movable in the direction. A drum 2 is provided between the oil pump 13 and the rear clutch 2.
2. A front clutch 1, substantially similar to the rear clutch 2, having a piston 18', a return spring 17', a driven plate 19' and a drive plate 20' is rotatably mounted on the oil pump cover 11. The drive plate 20' of the front clutch 1 is slidably engaged with the rear clutch drum 10 in the axial direction by a spline on its inner diameter, and the front clutch drum 22 is engaged with a member 23 by a spline at its distal end.
furthermore, the front clutch drum 22
A band brake 5 is provided with a slight clearance around the outer periphery of the band brake 5. The above-mentioned operation of the rear clutch 2 and front clutch 1 is performed by a control valve device 25 provided in the oil in the oil pan 24, and the operating hydraulic pressure is applied to the oil passage provided in the oil pump 13 (see Fig. 2). is supplied to each clutch from a control valve device 25 via an oil passage 26 to the rear clutch 2 (only the oil passage 26 is shown). When the driver selects the neutral position, the manual valve 25 in the control valve device 25 is in the position shown in FIG. The oil passage 27 on which the pressure (pressure) acts is located at the raised part 2 of the manual valve 26
Line pressure does not act on the oil passage 29 which is closed by the oil passage 8 and connected to the oil passage 26 communicating with the rear clutch 2, and the oil passage 29 is opened into the oil pan 24 by the oil passage 30. There is. Therefore, no hydraulic pressure should act on the piston 18 of the rear clutch 2 in the neutral position. However, as mentioned above, even in the neutral position, the rear clutch drum 10 is rotated by the rotational force of the engine via the input shaft 8, and the oil remaining between the rear clutch drum 10 and the piston 18 is This rotation causes centrifugal force to act, which causes hydraulic pressure to act on the piston 18. Since this oil pressure is small while the rotational speed is low, it does not push the piston 18 to the right against the force of the return spring 17, but when the rotation increases, for example when the engine is revving, the oil pressure due to centrifugal force also increases. becomes larger, pushing the piston 18 to the right against the force of the return spring 17. Therefore, the drive plate 20 and the driven plate 19 try to start fastening, but
Since the hydraulic pressure is not sufficiently large, complete fastening is not possible, and the drive plate 20 and driven plate 19 will rotate relative to each other while remaining in loose contact, resulting in a problem that both plates will burn out. To prevent this, a pressure relief device is generally provided on the rear clutch drum 10 or the piston 18. In the case of FIG. 2, a pressure evacuation device 31 using a steel ball is provided on the piston 18. That is, this device 31 consists of a cylinder having a conical bearing surface on the inside and a rigid ball disposed in the cylinder so as to be able to move freely.When hydraulic pressure is applied to the clutch circuit, this hydraulic pressure causes the rigid ball to move freely. is pressed against the conical bearing surface and closed, but when the hydraulic pressure drops below a certain value, the rigid ball separates from the conical bearing surface due to gravity, creating a gap between the conical bearing surface and the rigid ball, and draining the oil inside the clutch. It is becoming possible to do so. However, with such a conventional discharge device, it has not been possible to completely eliminate the above-mentioned problems due to the following reasons. That is, the starting point of the oil passage 26 to the rear clutch drum 10 is the control valve device 25 immersed in the hydraulic oil in the oil pan 24.
from this starting point to the rear clutch drum 10.
Since the oil passage 26 is sealed to prevent oil pressure from leaking, the rear clutch drum 10 and piston 1
8 is discharged by the discharge device 31, the inside of the oil passage 26 becomes negative pressure, and the oil in the oil pan 24 is sucked up into the oil passage 26. Therefore, the oil in the rear clutch drum 10 is not completely drained, and there is always some oil sucked up, which generates oil pressure due to centrifugal force as described above, causing friction between the drive plate 20 and the driven plate 19. The surface will be burnt out and it will not be able to function normally. Therefore, the present invention is provided with a hydraulic pressure removing device that can drain the oil in the drum so as not to burn out the friction surface of the multi-disc clutch when the engine is rotated at high speed with the manual valve in the neutral position. The objective is to obtain an automatic transmission with improved performance. Hereinafter, the present invention will be explained based on FIGS. 4-8 of the accompanying drawings showing embodiments thereof. FIG. 4 is a partial sectional view similar to FIG. 2 of an automatic transmission using the oil pressure removal device according to the present invention, except for the part where the one-way valve 32 is provided in the middle of the oil passage 26. Since it is the same as that shown in , a detailed explanation of the configuration will be omitted. Further, the same reference numerals are used for the same members as those shown in FIG. The one-way valve 32 is the control valve device 2
5 to the rear clutch drum 10 and is not immersed in hydraulic oil, the oil passage 26 opens to suck air from outside the oil passage 26 when the oil passage 26 becomes negative pressure. This is a one-way valve arranged to close when hydraulic pressure is applied to 26 to prevent oil pressure from leaking. The configuration of the one-way valve 32 is
As shown in the figure. This one-way valve 32 has a stepped hole 34 formed in a boss portion 33 provided on the oil pump cover 11 from the oil passage 26 side, and a steel ball 35 having a diameter suitable for closing the small diameter hole is inserted into the large diameter hole. Charge, Brag 3
By driving the ball 6, the steel ball 35 is prevented from slipping out. Note that the one-way valve 32 is not limited to the above example,
Any type of valve may be used as long as it has a one-way function. For example, the example shown in FIG. 6 is almost the same as the one-way valve shown in FIG.
Remove the steel ball 35 from the oil pump cover 11.
This is prevented by providing a protrusion 37 on the oil pump housing 12 facing the oil pump housing 12. In the example shown in FIG.
A one-way valve assembly 41 in which a steel ball 35 is inserted into a cylinder 40 having a claw portion 39 to prevent the steel ball from coming out is press-fitted into the oil pump cover 11. The example shown in FIG. 8 is the oil pump cover 1.
This is a one-way valve consisting of a hole 42 provided in a hole 42 and a leaf spring 44 fixed by a rivet 43 to close the hole 42. As explained above, the control valve device 25
By providing a one-way valve 32 in the middle of the oil passage 26 from the rear clutch drum 10 to the rear clutch drum 10, even if negative pressure is generated in the oil passage 26, air is only sucked in through the one-way valve 32. , the hydraulic oil in the oil pan 24 is not sucked up. Therefore, the oil in the rear clutch drum 10 is completely drained.
Since there is no oil in the rear clutch drum 10, no hydraulic pressure is generated due to centrifugal force no matter what speed the rear clutch drum 10 rotates at. Therefore, the piston 18
It is always pushed back by the force of the return spring 17, and does not press the drive plate 20 and the driven plate 19. In this way, the aforementioned problem of burnout of the clutch friction surface in conventional automatic transmissions can be completely prevented. In addition to the above effects, the present invention also provides the following effects. That is, since the oil in the rear clutch drum 10 is discharged and the inside is filled with air, when the manual valve 26 is switched from the neutral position to the forward position, the hydraulic oil enters after removing the air. Due to this cushion effect, the oil pressure rises slowly, and the shock associated with switching the manual valve 26 is reduced. In the above example, a one-way valve was provided in the oil passage leading to the rear clutch 2, but the front clutch 1 also has a control valve device 25.
It is clear that the same effect as in the case of the rear clutch can be obtained by providing a one-way valve in a portion of the path from the front clutch drum 22 to the front clutch drum 22 which is not immersed in hydraulic fluid. It is also clear that both oil passages to the front clutch 1 and the rear clutch 2 can be provided with one-way valves. The above explanation was about an automatic transmission with 3 forward speeds and 1 reverse speed, but any other type of automatic transmission can be used to connect the oil passages of any clutch, brake, etc. from the control valve position. It does not depart from the scope of the present invention to provide a one-way valve at any location not immersed in hydraulic oil.
It is also clear that the present invention can be applied to transmissions other than automobiles.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the framework of the structure of an automatic transmission to which the present invention is applied, FIG. 2 is a partially sectional front view of a conventional automatic transmission, FIG. 3 is a schematic diagram showing a manual valve, and FIG. 5 is a sectional view showing a one-way valve, and FIGS. 6, 7, and 8 are sectional views showing different one-way valves. 1...Front clutch, 2...Rear clutch, 25...Control valve device, 26...
Oil line, 32...one-way valve.

Claims (1)

[Claims] 1. A front and rear clutch operated by hydraulic pressure is provided, and hydraulic oil is supplied from a control valve device to each clutch via each oil passage, and there is no drain in the oil passage to the rear clutch. In an automatic transmission equipped with a pressure device, a part of the oil path from the control valve device to the clutch in which hydraulic oil is not immersed in hydraulic oil is installed to prevent the flow from inside the oil path to the outside of the oil path. An automatic transmission equipped with a clutch internal hydraulic pressure removal device, characterized in that a one-way valve is provided to allow flow from outside the oil path into the inside of the oil path. 2. An automatic transmission equipped with the clutch internal hydraulic pressure removing device according to claim 1, wherein a one-way valve is provided in the oil path to the front clutch. 3. An automatic transmission equipped with the clutch internal hydraulic pressure removing device according to claim 2, wherein a one-way valve is provided in the oil path to the rear clutch.