KR20120058663A - Hydraulic brake - Google Patents

Abstract

PURPOSE: A hydraulic brake is provided to increase brake torque capacity by using a piston module which is installed within a cylinder and operated by fluid pressure and to improve auto transmission efficiency and fuel efficiency of a vehicle. CONSTITUTION: A space for brake operation is formed in the inner side of a case(210). A cylinder(230) forms a fluid pressure operation space within the case. A piston module(220) is installed within the cylinder and operated by fluid pressure. Operation plates(260) are pressurized to an axial direction by the piston module. Friction discs are alternately arranged with the operation plates. A first piston moves to the axial direction by operation fluid pressure entered in the cylinder. An elastic member provides elastic force as opposed to the operation fluid pressure to the first piston. A second piston is combined with an external diameter unit of the first piston which can be rotated.

Description

Hydraulic Brake {HYDRAULIC BRAKE}

The present invention relates to a hydraulic brake for use in an automatic transmission, and more particularly, to reduce the number of friction disks, to reduce the drag torque generated when the brake is inactive, and at the same time improved hydraulic brake assembly It is about.

As is well known, an automatic transmission is a device that automatically shifts to an appropriate shift stage according to a driving state of a vehicle. In order to implement such automatic transmission, the automatic transmission includes a planetary gear set including sun gear, ring gear, and planet carrier as its operating members. and at least one set, and a plurality of friction elements, such as a clutch and a brake, are provided to control the operation of such operating members.

And the automatic transmission is equipped with a hydraulic control system (hydraulic control system) for hydraulically controlling such friction elements. Accordingly, the clutches and the brakes determined according to the shift stages are controlled to be engaged or released by the hydraulic control system, thereby implementing each shift stage.

Among the friction elements, the brake serves to stop or prevent the rotation of the operating member of the planetary gear set that is rotating.

Such brakes are used to stop rotating members in general machines as well as automatic transmissions.

1 is a cross-sectional view showing a hydraulic brake of an automatic transmission according to the prior art. Although the hydraulic brake applied to the automatic transmission is shown for convenience of description, the present invention is not limited thereto and may be applied to a general machine.

As shown in FIG. 1, a hydraulic brake 100 of a conventional automatic transmission is installed in a transmission case 110.

The hydraulic brake 100 is a cylinder 130 formed in the case 110, a piston 120 is operated by the hydraulic pressure is inserted into the cylinder 130 is input, and the piston 120 And a return spring 140 disposed at an opposite position of the cylinder 130 to apply a restoring force to the piston 120.

Sealing members 143 and 144 are interposed between the outer diameter portion and the inner diameter portion of the piston 120 and the cylinder 130, respectively.

The return spring 140 is fixed to and supported by the case 110 by a snap ring 145.

In addition, the brake hub 150 of the automatic transmission includes a plurality of friction disks 170 on its outer circumferential surface in a spline structure, and the case 110 has a plurality of operations. Operating plates 160 are provided on their inner circumferential surface in a splined structure. The friction disks 170 and the operating plates 160 are alternately arranged.

An oil hole 115 is formed in the case 110 to supply oil to the cylinder 130. In this way, the oil supplied to the cylinder 130 presses the piston 120 to the left in the drawing to overcome the elastic force of the return spring 140 and moves the piston 120 to the left in the drawing.

Thus, the piston 120 presses the actuation plates 160 along the axial direction, such that the actuation plates 160 and the friction discs 170 engage by the friction force between them. . By this process, rotation of the brake hub 150 is stopped.

When the oil supply to the cylinder 130 through the oil hole 115 is stopped, the piston 120 is moved to the right in the drawing by the restoring force of the return spring 140, and thus the operating plates 160 engaged with each other. ) And friction disks 170 are disengaged from their engaged state. Accordingly, the brake hub 150 is in a rotatable state.

However, in the hydraulic brake 100 used in an automatic transmission or the like, oil is applied to the friction disk 170 and the operation plate in order to cool the heat generated by the slip between the operation plate 160 and the friction disk 170 during engagement. 160) to supply continuously.

As is well known, when the brakes are not engaged, the friction disks 170 rotate at an arbitrary speed by the brake hub 150 connected to the planetary gear member, and the operation plates 160 are connected to the transmission case and stopped. have.

However, since the oil supplied for cooling is continuously supplied even when the brake is not engaged, the rotational resistance, that is, the drag torque, is between the friction disks 170 and the operation plates 60 which are in relative rotational motion due to the viscosity of the oil. ) Will occur.

The drag torque accounts for up to 40% of the total power loss of the automatic transmission and is a major cause of reducing the efficiency of the automatic transmission.

In order to reduce the drag torque, it is most desirable to reduce the number of friction disks used, but there is a problem in that it is not possible to secure the torque capacity of the required brake.

In conventional hydraulic brakes, the piston area has to be increased or the number of friction disks has to be increased in order to sufficiently secure the torque capacity of the brake. However, when the installation space of the brake is limited, such as in an automatic transmission, it is difficult to increase the diameter of the piston. Therefore, the torque capacity of the brake has been secured mainly by increasing the number of friction disks, which results in an increase in drag torque. Caused.

In addition, the hydraulic brake of the conventional automatic transmission, the operator inserts the piston 120, the return spring 140 into the cylinder 130, respectively, in the transmission assembly line, the press spring using the return spring 140 After pressing, the snap ring 145 is fastened to the case 110, and thus there is a problem in that a production cycle of the transmission is lengthened.

The present invention has been made to solve the above problems, to increase the mechanical strength of the piston to ensure the maximum torque capacity in a given installation space, the hydraulic brake that can reduce the number of friction disks The purpose is to provide.

In addition, in order to reduce the assembly time of the hydraulic brake in the transmission assembly line, by supplying a piston module incorporating a piston, a return spring, etc., the operator inserts the piston module into the cylinder and fastens the piston module with a snap ring without using a press. Another purpose is to drastically reduce the assembly time of the transmission.

In order to achieve the above object, the hydraulic brake according to a preferred embodiment of the present invention is a cylinder formed in a case of a transmission, a piston module installed in the cylinder and operated by operating hydraulic pressure, the axial direction by the operation of the piston module Working plates pressurized with; And friction disks which are alternately disposed and pressurized with the operation plates.

The piston module may include a first piston, a second piston, a return spring, and a sub plate, and may be assembled into one module.

The outer diameter portion and the inner diameter portion of the first piston are in close contact with the cylinder to reciprocate in the axial direction by operating hydraulic pressure. Sealing members may be provided at the outer diameter portion and the inner diameter portion of the first piston, respectively.

The outer diameter portion of the first piston may include an extension part for guiding the second piston. The extension part may be formed with a guide pin groove.

The outer diameter portion of the second piston is in close contact with the extension portion of the first piston and perturbed, and a hole for fixing the guide pin may be formed.

The guide pin is inserted into and fixed to the hole of the second piston and is inserted into the guide pin groove of the first piston extension to guide the movement of the first piston and the second piston.

The left end of the outer diameter portion of the second piston may be formed with a pressing portion for pressing the operating plate.

A return spring and a sub plate are installed between the first piston and the second piston. The outer diameter portion of the sub plate is in contact with the first piston, and the inner diameter portion thereof is supported by the case.

The outer diameter portion of the return spring may be in contact with the sub plate and the inner diameter portion may be supported by the case. The sub plate is installed to reinforce the strength of the return spring when the piston module 220 is operated to have sufficient fatigue life, and may be omitted in some cases.

After the piston module is inserted into the cylinder, it may be fixed to the case by a snap ring.

According to the present invention, by using a piston module which kinematically increases the force of the piston in a limited space. The torque capacity of the brakes can be increased without increasing the size of the brakes or the number of friction dacks.

On the other hand, the number of friction disks can be reduced by the increased torque capacity, which reduces the drag torque of the brake. Reduced drag torque increases the efficiency of the automatic transmission, thereby improving the fuel economy of the car.

In addition, the discharge oil pressure of the oil pump can be lowered by the increased torque capacity, thereby increasing the efficiency of the automatic transmission.

On the other hand, according to the present invention, in the transmission assembly line, only the piston module, which is assembled by integrating the piston and the return spring in advance, is inserted. Therefore, the production cycle is shortened as compared with the case where the existing parts are separately assembled.

Usually two to three hydraulic brakes are used in the automatic transmission, if all of them are modularized, the efficiency of the transmission can be greatly improved, and the production cycle of the automatic transmission can be significantly shortened, thereby reducing the production cost.

On the other hand, in contrast to the existing hydraulic brakes, the piston module of the present invention increases the number of two to three parts, but due to the present invention, a large number of expensive friction disks and operating plates can be deleted, rather it can contribute to the material cost of the transmission.

1 is a cross-sectional view of a hydraulic brake of an automatic transmission according to the prior art.
2 is a cross-sectional view showing an inoperative state of the hydraulic brake of the automatic transmission according to the embodiment of the present invention.
3 is an assembled sectional view of the piston module according to the embodiment of the present invention.
4 is an exploded cross-sectional view of a piston module according to an embodiment of the present invention.
5 is a cross-sectional view showing an operating state of a piston module according to an embodiment of the present invention.
6 is an exploded perspective view of a piston module according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a cross-sectional view showing a non-operating state of the hydraulic brake of the automatic transmission according to a preferred embodiment of the present invention, Figure 3 is an assembled view of the piston module according to an embodiment of the present invention, Figure 4 is an exploded cross-sectional view of the piston module. to be. Figure 5 shows the operating state of the piston module, Figure 6 is an exploded perspective view of the piston module.

The hydraulic brake according to the embodiment of the present invention has been described in the case where it is applied to an automatic transmission for convenience of description, but is not limited thereto and may be applied to a general machine using hydraulic pressure or pneumatic pressure.

As shown in Figure 2, the hydraulic brake 200 of the automatic transmission according to an embodiment of the present invention is installed in the cylinder 230, the cylinder 230 formed in the case 210 of the transmission and is operated by the operating hydraulic pressure Piston module 220, the operation plate 260 is pressed in the axial direction by the operation of the piston module 220; And friction disks 270 that are alternately disposed and pressurized with the actuation plates 260.

The piston module 220 is supported and fixed to the case 210 by a snap ring 245, and the case 210 has an oil hole 215 for supplying hydraulic pressure to the piston module 220. Formed.

As shown in FIG. 3, the piston module 220 includes a first piston 290, a second piston 280, a return spring 240, a sub plate 255, and a guide pin 285. It can be manufactured in one assembled module.

The outer diameter portion and the inner diameter portion of the first piston 290 are in close contact with the cylinder 230 to reciprocate in the axial direction by operating hydraulic pressure. Sealing members 243 and 244 may be provided at the outer diameter portion and the inner diameter portion of the first piston 290, respectively.

As shown in FIG. 4, the outer diameter portion of the first piston 290 may include an extension part 222 for guiding the second piston 280. Guide pin grooves 224 may be formed in the extension part 222.

The outer diameter portion of the second piston 280 may be in close contact with the extension part 222 of the first piston 290 and perturb, and a hole 286 may be formed to fix the guide pin 285.

The guide pin 285 is inserted into and fixed to the hole 286 of the second piston and is inserted into the guide pin groove 224 of the first piston extension 222 so as to be connected to the first piston 290. The movement of the second piston 280 is guided.

The left end of the outer diameter portion of the second piston 280 may be formed with a pressing portion 282 for pressing the operating plate 260. In addition, the inner diameter portion of the second piston 280 is in contact with the return spring 240 through the contact portion 287 (FIG. 4).

The return spring 240 and the sub plate 255 are installed between the first piston 290 and the second piston 280. The outer diameter portion of the sub plate 255 is in contact with the first piston 290, and the inner diameter portion thereof may be supported by the case 210 through the finger portion 257. (Figure 2)

The outer diameter portion of the return spring 240 may be in contact with the sub plate 255 and the inner diameter portion may be supported by the case 210 through a finger 241 formed in the inner diameter portion. The finger 241 of the return spring 240 may pass through the finger groove portion (not shown) of the sub plate 255 and may be supported by the case 210 (FIG. 6).

The sub plate 255 is installed to reinforce the strength of the return spring 240 when the piston module 220 is operated. In some cases, the sub plate 255 may be omitted.

As shown in FIG. 2, the piston module 220 may be inserted into the cylinder 230 and then fixed to the case 210 by a snap ring 245.

Hereinafter will be described the operating principle of the piston module 220 according to an embodiment of the present invention. 5 shows the operating state of the piston module.

As shown in FIGS. 2, 3, 4 and 5, when the hydraulic pressure is supplied to the cylinder 230 through the oil hole 215, the first piston 290 moves to the left in the drawing.

At this time, the sub plate 255, which is in contact with the first piston 290, transmits a piston force to the return spring 240 and moves to the left side together with the return spring 240. However, since the return spring 240 is in contact with the second piston 280 and the contact portion 287, the movement of the return spring 240 is transmitted to the second piston 280 to transmit the second piston. The pressing portion 282 is to press the operating plate 260 is to operate the hydraulic brake. That is, the force of the hydraulic pressure of the first piston 290 is transmitted to the second piston 280 through the sub plate 255, the return spring 240, and the contact portion 287.

When the hydraulic pressure is released, the return spring 240 moves the subplate 255 and the first piston 290 to the right in the drawing to return to the original position, thereby releasing the brake. At this time, the second piston 280 is returned to its original position (right side in the drawing) by the guide pin 285 inserted into the guide pin groove 224. Meanwhile, the sub plate 255 is provided to reinforce the strength of the return spring 240. In some cases, the subplate 255 may be omitted so that the force of the first piston 290 is directly transmitted through the return spring 240. And act on 280.

Meanwhile, as illustrated in FIG. 5, when the piston force F1 of the first piston 290 is transmitted to the second piston 280, the lever piston of the return spring 240 causes the The force (F2) is shown to increase and the principle is explained as follows.

As shown in FIG. 5, the force F1 acting on the first piston 290 by operating hydraulic pressure acts on the subplate 255 and the return spring 240 through the first acting point a. The second piston is in contact with the return spring 240 and the second working point b to receive the pressing force F2 from the return spring 240. This second working point (b) is located closer to the hinge point (0) than the first working point (a), so that the pressing force (F2) that the return spring 240 transmits to the second piston 280 is the return spring 240 is greater than the force (F1) corresponding to the operating hydraulic pressure transmitted from the first piston 290. In other words, the relational expression [Equation 1] is established by the lever principle.

[Formula 1]

F1 * L1 = F2 * L2

Here, L1 is a vertical distance from the hinge point 0 to the first working point a, and L2 is a vertical distance from the hinge point 0 to the second working point b.

As shown in FIG. 5, since L1 is larger than L2, the pressing force F2 of the second piston is greater than the first piston force F1 corresponding to the hydraulic pressure. That is, according to the embodiment of the present invention, the pressing force F2 of the piston module (or the second piston) generated by the same operating hydraulic pressure is increased. Therefore, even if the number of friction disks 270 is reduced, sufficient torque capacity can be ensured. Comparing Fig. 1 and Fig. 2, the number of friction disks can be seen to be reduced from six to three. (50% decrease)

Meanwhile, the piston module 220 according to the present invention is already supported by the guide pin 285 because the preload of the return spring 240 is already applied therein, so that the piston module (without the use of a press in the transmission production line) Since only the snap ring 245 is inserted into the cylinder 230 and then the snap ring 245 is fastened, the assembling process is simplified and the assembly time is greatly reduced, thereby reducing the production cost of the transmission.

In addition, the hydraulic brake according to the present invention uses a piston module that can increase the action force of the piston without expanding the space of the existing hydraulic brake, so that the torque capacity without increasing the number of friction disks, or the number of friction disks It is possible to maintain the same torque capacity as conventional hydraulic brakes while reducing the pressure.

Accordingly, drag torque generated when non-locking of the hydraulic brake can be reduced, thereby improving the efficiency of the transmission and the fuel efficiency of the vehicle using the same.

Since the magnitude of the drag torque is directly proportional to the number of friction disks, it means that the drag torque can be reduced by 50% or more in the embodiment of the present invention.

In addition, according to the embodiment of the present invention, since the torque capacity of the brake can be increased by using the piston module, the magnitude of the hydraulic pressure acting on the brake can be reduced. When the operating oil pressure of the brake is lowered, the discharge oil pressure of the oil pump can be lowered, thereby reducing the power consumption of the oil pump, thereby improving the efficiency of the automatic transmission.

So far, embodiments of the clutch module in which the piston, the return spring, and the sub-plate are assembled in advance have been described. However, the present invention is not limited thereto. Parts can also be assembled directly to the transmission case.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And all changes to the scope that are deemed to be valid.

Claims (13)

A case having a space formed therein for brake operation;
A cylinder defining a hydraulic operating space in the case;
A piston module installed in the cylinder and operated by hydraulic pressure;
Operating plates pressurized in the axial direction by the piston module; And
Friction disks alternately arranged with the actuation plates;
Including,
The piston module may include a first piston moving in an axial direction by operating hydraulic pressure flowing into the cylinder, an elastic member providing an elastic force against the operating hydraulic pressure to the first piston, and an outer diameter portion of the first piston. And a second piston movably coupled to the outer diameter and installed so that the inner diameter contacts the elastic member. The method of claim 1,
Hydraulic brakes, characterized in that the sealing member is provided in each of the portion where the outer diameter and the inner diameter of the first piston contact the inner peripheral surface of the cylinder. The method of claim 2,
The outer diameter portion of the first piston includes at least one extension protruding in the axial direction, the outer diameter portion of the second piston hydraulic brake, characterized in that movably coupled to the inner peripheral surface of the extension. The method of claim 3,
A guide hole is formed in the extension portion in the axial direction, and a guide groove corresponding to the guide hole is formed in the second piston.
And the second piston is movably coupled to the first piston by a guide pin fastened to the guide groove through the guide hole. The method of claim 4, wherein
The elastic member is
A ring shaped first rim; And
At least one first finger protruding radially inward from an inner circumferential surface of the first rim;
Hydraulic brake comprising a. The method of claim 5,
The piston module hydraulic brake further comprises a sub plate for reinforcing the strength of the elastic member. The method of claim 6,
The sub plate is
A second rim in close contact with the first rim; And
At least one second finger protruding radially inward from an inner circumferential surface of the second rim and alternately disposed with the first finger;
Hydraulic brake comprising a. The method of claim 7, wherein
Hydraulic brake, characterized in that the end of the first finger and the end of the second finger is located near in the axial direction and the radial direction. The method of claim 8,
Hydraulic brake, characterized in that the end of the first finger and the end of the second finger is supported at the same time by a snap ring mounted to the cylinder. The method of claim 1,
Hydraulic brake, characterized in that the outer portion of the second piston protruding in the axial direction the pressing portion for pressing the operating plates and the friction disks. The method of claim 1,
The piston module is a hydraulic brake, characterized in that pre-fabricated by using the first piston, the elastic member and the second piston as a module. The method of claim 1,
The first piston transfers a force corresponding to the hydraulic pressure to the second piston through the elastic member, and the second piston converts the force corresponding to the hydraulic pressure received from the first piston into a pressing force to operate the force. Hydraulic brake, characterized in that transmitted to the plate. The method of claim 12,
The radius of the point at which the first piston transmits a force corresponding to the hydraulic pressure to the elastic member is greater than the radius of the point at which the elastic member transmits a force corresponding to the hydraulic pressure to the second piston, so that the pressing force is the actuation force. Hydraulic brake, characterized in that greater than the force corresponding to the hydraulic pressure.

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