JPH0450454B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a hydraulic clutch used, for example, in an automatic transmission for a vehicle, and is intended to rapidly disengage the hydraulic clutch. <Prior Art> Hydraulic clutches have been used as components of automatic transmissions for vehicles, for example. First, the automatic transmission for a vehicle will be explained with reference to FIG. A crankshaft 2 of an engine 1 serving as a power source for the vehicle is directly connected to a pump 4 of a torque converter 3. The torque converter 3 includes a pump 4, a turbine 5, a stator 6, and a one-way clutch 7. The stator 6 is coupled to a case 8 via the one-way clutch 7, and the one-way clutch 7 moves the stator 6 in the same direction as the crankshaft 2. rotates, but the structure does not allow rotation in the opposite direction. The torque transmitted to the turbine 5 is transmitted by an input shaft 10 to a gear transmission 11 disposed at the rear thereof that achieves four forward speeds and one reverse speed. The gear transmission 11 includes three sets of hydraulic clutches 12, 13, 14 and two sets of hydraulic brakes 1.
5, 16, one set of one-way clutches 17, and one set of Ravigneau type planetary gear mechanism 18. This planetary gear mechanism 18 has a ring gear 1
9. Consists of a long pinion gear 20, a short pinion gear 21, a front sun gear 22, a rear sun gear 23, and a carrier 24 that rotatably supports both pinion gears 20 and 21 and is also rotatable, and the ring gear 19 is connected to the output shaft 25. The front sun gear 22 connects to the input shaft 1 via the kickdown drum 26 and the front clutch 12.
0, the rear sun gear 23 is connected to the input shaft 10 via the rear clutch 13, and the rear sun gear 23 is connected to the input shaft 10 via the rear clutch 13.
4 is connected to the case 8 via a low reverse brake 16 and a one-way clutch 17 which are arranged functionally in parallel, and via a 4th clutch 14 arranged at the rear end of the gear transmission 11. It is connected to the input shaft 10. In addition, the above-mentioned kick-down drum 26 is used as the kick-down brake 1.
5, it can be fixedly connected to the case 8. Torque passing through the planetary gear mechanism 18 is transmitted from an output gear 30 fixed to an output shaft 25 via an idle gear 31 to a driven gear 32, and further to a transfer shaft 33 and a helical gear 34 fixed to the driven gear 32. The signal is transmitted to a differential gear device 36 to which the drive shaft 35 is connected. Each of the above-mentioned hydraulic clutches and hydraulic brakes is composed of a friction engagement device equipped with an engagement piston device or a servo device, etc., and is driven by an engine 1 by being connected to a pump 4 of a torque converter 3 (not shown). It is operated by hydraulic pressure generated by an oil pump (hydraulic supply source). This hydraulic pressure is selectively supplied to each hydraulic clutch and hydraulic brake by a hydraulic control device according to the operating state detected by various operating state detection devices, and is applied to the combination of operation of each hydraulic clutch and hydraulic brake. As a result, four forward speeds and one reverse speed are achieved as shown in the table. In the table, the ○ mark indicates the engagement state of each hydraulic clutch or hydraulic brake, and the 〓 mark indicates the engagement state of each hydraulic clutch or hydraulic brake.
6 shows that the rotation of the carrier 24 is stopped by the action of the one-way clutch 17 immediately before the clutch 6 is engaged.

[Table] Here, as shown in FIG. 3 as a representative of the rear clutch 13, the rear clutch 1, which is a hydraulic clutch,
3, a switching valve (not shown) is switched so that an oil pump (not shown), which is a hydraulic pressure supply source, is communicated with the hydraulic chamber 13a of the rear clutch 13, and this supplied hydraulic pressure is used to form a hydraulic pressure in the hydraulic chamber 13a. The discharge port 13b is closed by a check valve 40, which is a discharge check valve provided at the discharge port 13b, and the clutch piston 13 is closed by the hydraulic pressure in the hydraulic chamber 13a.
c is pushed forward, and the input shaft 10, which is a rotating shaft, is engaged with the sun gear shaft 23a. Furthermore, when releasing the rear clutch 13, the switching valve is switched to communicate the hydraulic chamber 13a with an oil pan (not shown) serving as a hydraulic discharge device.
The oil pressure inside the pump is lowered, and the check valve 40 opens the discharge port 13b due to the centrifugal force caused by the rotation of the input shaft 10. As a result, the clutch piston 13c is pushed back by the spring force of the return spring 41, and the oil in the hydraulic chamber 13a is discharged from the discharge port 13b, and the rear clutch 13 is released. By the way, when the check valve 40 opens the discharge port 13b as described above, the oil in the hydraulic chamber 13a is discharged to the outside from the discharge port 13b due to centrifugal force. However, if the centrifugal force is large, a centrifugal pump action will occur, and oil will be sucked into this hydraulic chamber 13a from the oil pan as the oil is discharged, resulting in failure to release the clutch, or failure to disengage the clutch, resulting in burnout of the clutch. There was a problem that caused the problem. Therefore, in order to solve the above problems, as disclosed in Japanese Utility Model Application Publication No. 59-39349,
A passage is formed inside the discharge port 13b in the radial direction to communicate the hydraulic chamber 13a with the outside, and the hydraulic chamber 1 is formed in this passage as the oil is discharged from the discharge port 13b.
This passage is opened by the negative pressure in 3a, and the hydraulic chamber 13 is opened.
Those equipped with a check valve that communicates a with the outside,
Instead of the above-mentioned passage, a check valve is provided in the middle of the oil supply/drainage path for the hydraulic pressure to the hydraulic chamber 13a. and,
In both of these systems, when the clutch is released, oil is discharged from the discharge port 13b and air is introduced from the outside into the hydraulic chamber 13a from the oil pan to the hydraulic chamber 13a.
This prevents oil from being sucked into 3a. <Problems to be Solved by the Invention> The above-mentioned means for guiding air to the hydraulic chamber 13a can prevent oil from being sucked in by the action of the centrifugal pump, and can ensure the discharge of oil from the discharge port 13b. . However, even while the oil is being discharged, the clutch piston 13c is pressed by the hydraulic pressure generated by the centrifugal force on the oil remaining in the hydraulic chamber 13a, so that the oil in the hydraulic chamber 13a is being discharged. Since the clutch piston 13c is not pushed back until the hydraulic pressure due to the centrifugal force becomes equal to or less than the return force of the return spring 41, there has been a problem in that there is a delay in the clutch release operation. The present invention has been made in view of the above-mentioned conventional situation, and an object of the present invention is to provide a hydraulic clutch control device that realizes quick release operation of a hydraulic clutch. <Means for Solving the Problems> The hydraulic clutch control means according to the present invention includes a hydraulic clutch that is operated by hydraulic pressure being supplied to a hydraulic chamber to couple two rotating shafts, and a hydraulic clutch that connects two rotating shafts by hydraulic pressure being supplied to the hydraulic chamber. a switching valve that switches between the supply source and the hydraulic ejector for communication; and a suction prevention non-return check that is provided between the switching valve and the hydraulic ejector and allows oil to flow only toward the hydraulic ejector. A valve is provided at a discharge port formed in the hydraulic chamber and capable of discharging oil from the hydraulic chamber to the outside by centrifugal force accompanying rotation of the hydraulic clutch, and the hydraulic pressure is supplied to the hydraulic chamber from the hydraulic pressure supply source. and a discharge check valve that closes the discharge port by the hydraulic pressure when the discharge port is in the state where the discharge port is closed. <Function> When the hydraulic chamber of the hydraulic clutch is communicated with the hydraulic discharge device by switching the switching valve to release the clutch, even if oil is discharged from the discharge port and the pressure inside the hydraulic chamber becomes negative, the pressure will not be removed from the hydraulic discharge device. The suction prevention check valve reliably prevents oil from being sucked into the hydraulic chamber, and the negative pressure in the hydraulic chamber contributes to the push-back force of the clutch piston by the return spring, allowing the clutch piston to be pushed back quickly. be exposed. <Example> Hereinafter, an example in which the present invention is applied to the rear clutch of the above-mentioned automatic transmission for a vehicle will be described with reference to FIGS.
The explanation will be based on c. Incidentally, the same reference numerals are given to the same members as those already described, and redundant explanation will be omitted. As shown in FIGS. 1a and 1b, the rear clutch 13
The clutch retainer 13d constituting the input shaft 10
This clutch retainer 1 is spline fitted to
A clutch piston 13c is slidably attached to the clutch retainer 13d and the clutch piston 13c through a seal ring 42, and a hydraulic chamber 13a is formed by the clutch retainer 13d and the clutch piston 13c. The clutch retainer 13d has an oil passage 4 whose one end opens into the hydraulic chamber 13a.
3 is formed, and the other end of this oil passage 43 communicates with a solenoid valve 44 which is a switching valve provided in the hydraulic control circuit of the automatic transmission. The casing 44a of the solenoid valve 44 includes an oil supply/drain passage 45 communicating with the oil passage 43, a supply oil passage 46 communicating with an oil pump (not shown) which is a hydraulic pressure supply source, and an oil pan (oil pan) which is a hydraulic discharge device. (not shown) is formed. The mutual communication relationship between these oil passages 45, 46, and 47 is switched by a spool 44b of a solenoid valve 44, and the solenoid valve 44 connects the oil supply and drainage passage 45 and the supply oil passage as shown in FIG. 1a. 46 are in communication with each other, and as shown in FIG. 1B, the oil supply and discharge passage 45 and the discharge oil passage 47 are in communication with each other. A spool 44 is provided in the discharge oil path 47.
A check valve 48, which is a check valve for preventing suction, is located between the oil pan and the oil pan.
This check valve 48 allows oil to flow through the discharge oil path 47 only toward the oil pan side. Here, in this embodiment, the check valve 48 is installed inside the casing 44a, so that it can be arranged compactly without requiring a separate casing. In the figure, 13e and 13f are clutch plates that engage with the clutch retainer 13d and the sun gear shaft 23a, respectively, and can frictionally engage with each other, and 44
c is a return spring of the spool 44b. The operation of the hydraulic clutch control device having the above configuration will be explained. First, as shown in Figure 1a, the solenoid valve 4
When the oil supply/discharge path 45 of No. 4 and the oil supply path 46 are communicated and pressure oil is supplied from the oil pump to the hydraulic chamber 13a, the check valve 40 closes the discharge port 13b due to the hydraulic pressure in the hydraulic chamber 13a, and the clutch piston closes. 13c is pushed forward. As a result, the clutch plates 13e and 13f are pressed against and engaged with each other, and the input shaft 1 connected to the clutch retainer 13d
0 and the sun gear shaft 23a are coupled and rotate synchronously. Next, as shown in FIG. 1b, the oil supply/discharge path 45 and the oil discharge path 47 of the solenoid valve 44 are brought into communication to cut off the supply of pressure oil from the oil pump and to connect the hydraulic chamber 13a to the oil pan. When connected,
As the oil pressure in the hydraulic chamber 13a decreases, the check valve 40 moves due to the centrifugal force caused by the rotation of the input shaft 10, and a gap is opened at the discharge port 13b. As a result, centrifugal force causes the oil in the hydraulic chamber 13a to drain to the outlet 1.
3b to the outside, and due to the spring force of the return spring 41, the clutch piston 13c
is pushed back, and the connection between the input shaft 10 and the sun gear shaft 23a by the rear clutch 13 is released.
Here, when oil is discharged from the discharge port 13b as described above, a force is generated to suck the oil from the oil pan to the hydraulic chamber 13a due to the action of the centrifugal pump, but the flow of oil from the oil pan to the hydraulic chamber 13a is is blocked by check valve 48. As a result, as shown in FIG. 1c, a positive hydraulic pressure is generated in the hydraulic chamber 13a due to the centrifugal force and acts against the return spring 41, and a negative hydraulic pressure is applied to the return spring 41. As shown by the dotted line in the figure, the positive oil pressure amount is generally reduced compared to the case where there is no check valve 48 and oil is sucked from the oil pan. Therefore, the return spring 41
Since the opposing force to the solenoid valve 44 becomes smaller,
When the clutch piston 13c is switched, the clutch piston 13c is immediately pushed back and the clutch is disengaged, thereby avoiding a clutch disengagement failure. In addition, if the opening gap of the outlet 13b is set to be relatively large in order to improve the oil discharge ability, the oil supplied at low pressure will escape from the opening gap of the outlet 13b when the clutch is engaged. Therefore, when the supplied hydraulic pressure reaches a high pressure, the discharge port 13b is closed by the check valve 40, and the clutch is suddenly engaged, resulting in a problem that the shift shock becomes large. However, in the present invention, since the negative oil pressure in the hydraulic chamber 13a is applied to the return spring 41, good clutch disengagement can be achieved even if the opening gap of the discharge port 13b is set small. Therefore, according to the present invention, it is possible to realize a good speed change with a small speed change shock, and when the clutch is engaged during high speed rotation, the discharge port 13b is reliably closed with low pressure hydraulic pressure, so that the clutch is closed. It becomes possible to freely control the transmitted torque capacity by electrical means using a solenoid valve. The present invention is not limited to the above-mentioned embodiments, and can be applied to other hydraulic clutches of automatic transmissions and hydraulic clutches other than automatic transmissions. It may also be a manually operated spool valve or the like. <Effects of the Invention> According to the present invention, since the suction prevention check valve reliably prevents suction into the hydraulic chamber, a quick release operation of the hydraulic clutch is realized. Also,
By setting the opening gap of the discharge port small, it is possible to reduce the shift shock.

[Brief explanation of the drawing]

Figures 1a, b, and c respectively relate to one embodiment of the present invention; Figures 1a and b are cross-sectional views showing the upper half of the rear clutch and the solenoid valve, respectively; Figure 1c;
2 is a characteristic diagram showing oil pressure distribution, FIG. 2 is a schematic configuration diagram showing an example of an automatic transmission for a vehicle, and FIG. 3 is a sectional view showing the upper half of a conventional rear clutch. In the drawing, 13 is a rear clutch, 13a is a hydraulic chamber, 13b is a discharge port, 40 is a discharge check valve, 44 is a solenoid valve, 46 is a supply oil path, and 47
48 is a discharge oil passage, and 48 is a check valve for preventing suction.

Claims (1)

[Scope of Claims] 1. A hydraulic clutch that is activated by hydraulic pressure being supplied to a hydraulic chamber to connect two rotating shafts, and a switch that switches the hydraulic chamber into communication with a hydraulic pressure supply source and a hydraulic ejector. a check valve for preventing suction, which is provided between the switching valve and the hydraulic discharge device and allows oil to flow only toward the hydraulic discharge device; A discharge port that is provided at a discharge port that can discharge oil from the hydraulic chamber to the outside by centrifugal force accompanying the rotation of the hydraulic chamber, and that closes the discharge port by the hydraulic pressure when hydraulic pressure is supplied to the hydraulic chamber from the hydraulic pressure supply source. A hydraulic clutch control device characterized by comprising a check valve for use in a hydraulic clutch. 2. The switching valve according to claim 1, wherein the switching valve is a solenoid valve, and the suction prevention check valve is provided in an oil passage formed in a casing of the solenoid valve. Hydraulic clutch control device.