JP5637966B2 - accumulator - Google Patents

Description

  The present invention relates to an accumulator for an automatic transmission for a vehicle.

  An accumulator for supplying hydraulic pressure to a friction engagement element is provided in a hydraulic circuit of an automatic transmission for a vehicle (for example, Patent Document 1).

JP 2004-237774 A

FIG. 4 is a schematic configuration diagram of a hydraulic circuit including a conventional accumulator.
As shown in FIG. 4A, a conventional accumulator 100 as disclosed in Patent Document 1 includes a piston 102 provided in a cylindrical main body cylinder 101 so as to be movable in an axial direction, and a piston 102. A spring 103 that urges toward one end 101 a of the main body cylinder 101, a plug 104 that is internally fitted and fixed to the other end 101 b of the main body cylinder 101, and a base end of the spring 103 is attached, and a working fluid that has passed through the orifice 106. Is provided with a hydraulic oil passage 105 for supplying the pressure to the plug 104 in the main body cylinder 101, and an oil passage 107 for connecting the one end 101a side of the main body cylinder 101 and the hydraulic circuit 108 to supply the supply pressure of the piston 102.

  For example, when the accumulator 100 is a 1-2 accumulator that establishes shelf pressure control for the second speed when shifting from the first speed travel to the second speed travel, the accumulator 100 during the first speed travel is shown in FIG. ), The piston 102 is compressed by the supply pressure. When the shift from the first speed to the second speed is started, the piston 102 is moved to the one end 101a side while gradually increasing the hydraulic pressure (working hydraulic pressure) supplied to the back pressure side of the piston 102 in the main body cylinder 101, A shelf pressure for the second speed is generated by a pressing balance with the supply pressure supplied to the inside of the main body cylinder 101 (right side in the figure than the piston 102) (see FIG. 4B).

Here, when an abnormality such as an engine stall suddenly occurs during the transition from the first speed travel to the second speed travel, the supply pressure on the hydraulic circuit 108 side may be released at a stroke. In such a case, since the supply pressure to the piston 102 disappears all at once, the piston 102 biased toward one end by the spring 103 moves rapidly toward the one end 101a.
Here, the hydraulic oil passage 105 is provided with an orifice 106, so that oil cannot be supplied rapidly to the back pressure side of the piston 102 in the main body cylinder 101 even if the piston 102 moves suddenly. Therefore, a negative pressure state is generated on the back pressure side of the piston 102 in the main body cylinder 101.
Then, the plug 104 to which the base end of the spring 103 is attached may be attracted by the negative pressure and may move toward the one end 101a in the main body cylinder 101 (see FIG. 4C).

  After that, when the hydraulic pressure on the hydraulic circuit 108 side is restored and the supply pressure is applied to the piston 102 and the piston 102 is moved to the other end 101b side in the main body cylinder 101, it moves in an abnormal state. The plug 104, together with the piston 102, tends to return to the home position in the main body cylinder 101 toward the other end 101b. At this time, there is a possibility that the plug 104 sticks in the main body cylinder 101 without returning to the original position. In such a case, the control of the shelf pressure by the accumulator 100 may be hindered thereafter. There is.

  Therefore, it is required to prevent the plug from moving when a negative pressure state occurs on the back pressure side of the piston in the main body cylinder of the accumulator.

The present invention is an accumulator provided in a hydraulic circuit for supplying hydraulic pressure to a frictional engagement element of an automatic transmission, and is provided so as to be movable in the axial direction of the main body cylinder within the main body cylinder and the main body cylinder. A piston that urges the piston toward one end of the main body cylinder, and is fitted into the main body cylinder at the other end of the main body cylinder, and a proximal end of the spring is in contact A plug, an oil passage that supplies hydraulic pressure to one of the friction engagement elements, a supply-side oil passage that communicates with the inside of one end of the main body cylinder, and an oil passage that supplies hydraulic pressure to the other friction engagement element A back pressure side oil passage communicating with the inside of the other end of the main body cylinder and having an orifice interposed therein,
The plug is provided with a through-hole penetrating in the axial direction of the main body cylinder,
The accumulator has a configuration in which a check valve that allows only flow from the outside of the main body cylinder into the main body cylinder through the through hole is provided.

  According to the present invention, when a negative pressure state occurs in the other end side inside the main body cylinder (back pressure side of the piston), the main body cylinder is allowed to flow through the through hole and into the main body cylinder. The negative pressure state that can occur on the back pressure side of the piston is suppressed, and the plug can be suitably prevented from moving.

It is a schematic diagram of the accumulator concerning an embodiment. It is a figure explaining the principal part of the accumulator concerning an embodiment. It is a figure explaining the principal part of the accumulator concerning a modification. It is a schematic block diagram of a hydraulic circuit provided with the conventional accumulator.

Embodiments of the present invention will be described below.
FIG. 1 is a diagram schematically showing a cross section of an accumulator 1 according to an embodiment.
2A is an enlarged view around the plug 20 in FIG. 1, FIG. 2B is a cross-sectional view taken along line AA in FIG. 2A, and FIG. 2C is a cross-sectional view taken along line BB in FIG. FIG.

The accumulator 1 according to the embodiment is a 1-2 accumulator (1-2 ACCM) that establishes a shelf pressure control for the second speed when shifting from the first speed travel to the second speed travel, and is a control valve body of the automatic transmission. (Not shown).
A cylindrical main body cylinder 10 of the accumulator 1 is defined between overlapped valve bodies, and a piston 11 is provided inside the main body cylinder 10 so as to be slidable in the axial direction.

The piston 11 has a bottomed cylindrical shape, and is disposed with the bottom portion 11 a facing one end side of the main body cylinder 10. One end side of the spring 12 is inserted into the peripheral wall portion 11 b surrounding the bottom portion 11 a, and the piston 11 is urged toward one end side in the main body cylinder 10 by the spring 12.
In the embodiment, the spring 12 employs a coil spring having a length and a spring constant that causes the piston 11 to abut against the abutting portion 10a of the main body cylinder 10 with a predetermined urging force.

One end of the main body cylinder 10 is sealed by an abutting portion 10 a with which the bottom portion 11 a of the piston 11 abuts, and an oil passage 13 that applies supply pressure to the piston 11 is provided at one end from the circumferential direction of the main body cylinder 10. Connected and provided.
The oil passage 13 is offset in the axial direction of the main body cylinder 10 in a direction away from the piston 11 with respect to the contact portion 10a, and the bottom portion 11a of the piston 11 in contact with the contact portion 10a and the inner periphery of the oil passage 13 A gap S is secured between the surface 13a.

In the embodiment, the oil passage 13 is connected to an accumulator on which a LOW / C pressure acts via a hydraulic circuit, and supply pressure acting on the piston 11 is supplied via the oil passage 13. It has become.
By securing a gap S between the bottom portion 11a of the piston 11 and the inner peripheral surface 13a of the oil passage 13, the bottom portion 11a serving as a pressure receiving surface of the piston 11 when the piston 11 is in contact with the contact portion 10a. In addition, the supply pressure supplied from the oil passage 13 can act reliably.

The other end of the main body cylinder 10 is an open end 10b, and a rod-like retainer 16 is provided through the main body cylinder 10 in the vicinity of the open end 10b.
The retainer 16 is provided to prevent the plug 20, which is fitted and fixed to the other end side of the main body cylinder 10, from falling off from the main body cylinder 10.

The basic shape of the plug 20 has a columnar shape. In the main body cylinder 10, an accumulation chamber R is formed inside the contact portion 10 a and the plug 20.
A boss portion 21 having an outer diameter matching the inner diameter of the spring 12 is provided on the surface of the plug 20 on the piston 11 side, and a base end 12a of the spring 12 is attached to the boss portion 21 by being externally fitted. Yes.

In the main body cylinder 10, a back pressure oil passage 14 that supplies hydraulic pressure to the back pressure side of the piston 11 is connected to a position closer to the piston 11 than the plug 20.
The back pressure oil passage 14 is provided with an orifice 15 in the vicinity of the main body cylinder 10, and after the oil pressure supplied from the back pressure oil passage 14 passes through the orifice 15, the accumulator on the plug 20 side of the main body cylinder 10 is provided. It is supplied to the chamber R.
In the embodiment, the back pressure oil passage 14 is connected to an oil passage that supplies hydraulic pressure to a frictional engagement element different from the oil passage 13 described above.

  In the accumulator 1 according to the embodiment, when the vehicle is traveling at the first speed, the piston 11 pushes and contracts the spring 12 by the supply pressure supplied from the oil passage 13 and is moved to the vicinity of the plug 20. When the shift from the first to the second speed is started, the hydraulic pressure (back pressure) supplied from the back pressure oil passage 14 is gradually increased to move the piston 11 to one end side, so that the back pressure oil passage 14 side is moved. Controlled to supply hydraulic pressure.

In the accumulator 1 according to the embodiment, the plug 20 is provided with a one-way valve 22.
The one-way valve 22 blocks the discharge of the oil in the accumulation chamber R to the open end 10b side, and prevents the oil in the accumulation chamber R from being discharged to the open end 10b side of the main body cylinder 10. However, the inflow of oil into the accumulation chamber R from the open end 10b side is allowed.

As shown in FIG. 2A, the one-way valve 22 includes a through hole 23 that penetrates the plug 20 in the thickness direction and a ball (one-way ball) 24.
As shown in FIG. 2B, the through hole 23 is formed so as to avoid a position overlapping the retainer 16 when viewed from the axial direction. In the embodiment, the right side of the retainer 16 is viewed from the open end 10b side. A through hole 23 is opened.

As shown in FIG. 2A, the through hole 23 includes a through hole portion 23a on the retainer 16 side and a ball accommodating portion 23b on the accumulation chamber R side, and the through hole portion 23a and the ball accommodating portion 23b. Are continuously formed in the thickness direction of the plug 20.
The diameter of the ball accommodating portion 23b increases toward the accumulation chamber R (piston 11), and the ball 24 is accommodated therein.
The length L1 of the ball accommodating portion 23b in the thickness direction of the plug 20 is longer than the diameter L of the ball 24 so that the ball 24 in the ball accommodating portion 23b can move forward and backward in the thickness direction of the plug 20. Has been.

At the end of the plug 20 (boss portion 21) on the piston 11 side, a protruding portion 21a for preventing the ball 24 from falling off the through hole 23 is formed.
In the embodiment, the protruding portion 21a is formed to protrude into the through hole 23 (ball accommodating portion 23b) by caulking of the plug 20 made of aluminum.

As shown in FIG. 2 (c), four protrusions 21a are provided at equal intervals in the circumferential direction around the through hole 23, and the ball 24 moves to the right in FIG. 2 (a). Thus, the clearance CL is ensured between the ball 24 and the through hole 23 (ball accommodating portion 23b) while restricting the movement of the ball 24 when contacting the protruding portion 21a.
Therefore, when the ball 24 comes into contact with the protruding portion 21a, the oil that has flowed into the through hole 23 from the open end 10b side of the main body cylinder 10 creates a gap CL between the ball 24 and the through hole 23 (ball accommodating portion 23b). It can pass through into the accumulation chamber R.

By providing the plug 20 with the through hole 23 having such a configuration, when the hydraulic pressure (back pressure) is supplied from the back pressure oil passage 14 into the accumulator chamber R, or the supply pressure is supplied from the oil passage 13. In the state where oil is supplied into the accumulation chamber R as in the case, the ball 24 moves to the left side in FIG. 2A and is disposed at a position where the through hole 23a of the through hole 23 is closed. Is done.
Thereby, the discharge of the oil in the accumulation chamber R to the open end 10b side is blocked.

Further, when the supply pressure disappears all at once and the piston 11 rapidly moves to one end side of the main body cylinder 10 and a negative pressure state is generated on the plug 20 side than the piston 11 in the accumulator chamber R, the ball 24 is negatively pressurized. As a result, the ball accommodating portion 23b is moved to a position where it comes into contact with the protruding portion 21a on the accumulation chamber R side.
As a result, oil can flow into the accumulator chamber R from the open end 10b side of the main body cylinder 10 through the through hole 23, so that the negative pressure state generated in the accumulator chamber R due to the inflowed oil is reduced. Can be eliminated or alleviated. Therefore, since the force F1 that pulls the plug 20 toward the one end (contact portion 10a) in the main body cylinder 10 is relaxed, the plug 20 moves together with the piston 11 toward one end (contact portion 10a) in the main body cylinder 10. This can be suitably prevented.

Here, in the embodiment, when the through hole 23 is formed, the through hole 23 (through hole portion 23a) is provided so that the sliding resistance when the plug 20 slides in the main body cylinder 10 can maintain αF ≧ F1. The inner diameter (channel cross-sectional area) is set.
Here, α is a sliding resistance coefficient in oil of the plug 20 (sliding resistance coefficient when the plug 20 slides in the main body cylinder 10 filled with oil), and αF is an accumulator chamber R. F1 is a force necessary to move the plug 20 in the oil when a negative pressure state occurs in the inside, and F1 is a force that actually acts on the plug 20 when the negative pressure state occurs (the plug 20 This is a smaller force than when the through hole 23 is not formed.

As described above, in the embodiment, the accumulator 1 is provided in the hydraulic circuit that supplies the hydraulic pressure to the frictional engagement element of the automatic transmission, and includes the cylindrical main body cylinder 10 and the main body cylinder 10. A piston 11 provided so as to be slidable in the axial direction, a spring 12 that urges the piston 11 toward the contact portion 10a on one end side of the main body cylinder 10, and the other end (open end 10b) of the main body cylinder 10 ) Side is fitted and fixed to the main body cylinder 10, and the plug 20 to which the base end 12 a of the spring 12 is attached and the position of the main body cylinder 10 on the one end side of the plug 20 (the plug of the accumulator chamber R than the piston 11). A back pressure oil passage 14 that is connected to a position 20 on the side 20 and can supply the working fluid that has passed through the orifice 15 into the main body cylinder 10, and a main body series. It is connected to one end of the dust 10, an oil passage 13 for communicating the hydraulic circuit communicating with the frictional engagement element of the main cylinder 10 and the automatic transmission, provided with,
The plug 20 is provided with a through hole 23 penetrating in the axial direction of the main body cylinder 10, and a check valve that allows only fluid flow from the outside of the main body cylinder 10 to the inside of the main body cylinder 10 through the through hole 23. As a check valve, the flow of the working fluid discharged from the main body cylinder 10 through the through hole 23 to the open end 10b side of the main body cylinder 10 is cut off, and the open end 10b side enters the main body cylinder 10 The ball 24 allowing the inflow of the working fluid is adopted.

  With this configuration, when a negative pressure state occurs on the plug 20 side in the main body cylinder 10, the inflow of the working fluid into the main body cylinder 10 through the through hole 23 is allowed. Thus, the negative pressure state generated on the plug 20 side can be quickly eliminated to prevent the plug 20 from moving.

  In particular, since the accumulator 1 is a 1-2 accumulator (1-2 ACCM) that establishes the shelf pressure control for the second speed when shifting from the first speed traveling to the second speed traveling, Even when the back pressure of the accumulator 1 is drastically reduced due to the above, and the negative pressure is generated closer to the plug 20 than the piston 11 in the main body cylinder 10, the plug 20 is drawn into the main body cylinder 10 and stuck. There is nothing to do. Thereby, it can prevent suitably that a trouble arises in driving | running | working of subsequent vehicles.

In particular, when forming the through hole 23, the inner diameter of the through hole 23 (through hole portion 23a) is set so that the sliding resistance when the plug 20 slides in the main body cylinder 10 can maintain αF ≧ F1. It was.
Here, α is a sliding resistance coefficient of the plug 20 in the oil, and αF is a force required to move the plug 20 in the oil when a negative pressure state occurs in the accumulator chamber R. F1 is a force that actually acts on the plug 20 when a negative pressure state occurs.

If comprised in this way, when the negative pressure state generate | occur | produces in the plug 20 side in the main body cylinder 10, it can prevent suitably that the plug 20 moves to one end side, sliding in the main body cylinder 10. FIG.

Hereinafter, modifications of the one-way valve 22 provided in the plug 20 will be described.
3A and 3B are diagrams for explaining a one-way valve 22A according to a modified example, in which FIG. 3A is a cross-sectional view around the one-way valve 22A in the accumulator, and FIG. 3B is a cross-sectional view taken along line AA in FIG. It is a figure and (c) is BB sectional drawing in (a).

As shown in FIG. 3A, the one-way valve 22 </ b> A includes a through hole 23 </ b> A that penetrates the plug 20 in the thickness direction and a valve body 26.
As shown in FIG. 3B, the through hole 23A is formed so as to avoid a position overlapping the retainer 16 when viewed from the axial direction. In the embodiment, the right side of the retainer 16 is viewed from the open end 10b side. A through hole 23A is opened.

The through hole 23A is provided so as to penetrate the retainer 16 in the thickness direction, and has the same inner diameter over the entire length in the longitudinal direction.
The shaft portion 26a of the valve body 26 is inserted into the through hole 23A, and a rod-shaped locking portion 26b extending in a direction orthogonal to the shaft portion 26a is integrated with an end portion of the shaft portion 26a on the open end 10b side. Is provided. The locking portion 26b is longer than the inner diameter of the through hole 23A, and contacts the plug 20 when the valve body 26 moves to the accumulator chamber R side to prevent the valve body 26 from falling off the plug 20. It is supposed to be.

A disc-shaped lid portion 26c is attached to an end portion of the shaft portion 26a located in the accumulation chamber R. The lid portion 26c is formed with an outer diameter larger than the inner diameter of the through hole 23A. The lid portion 26c is formed separately from the shaft portion 26a, and is attached to the shaft portion 26a by, for example, screwing.
When the valve body 26 moves to the open end 10b side of the main body cylinder 10, the lid portion 26c comes into contact with the surface on the accumulation chamber R side of the plug 20 and closes the through hole 23A. The oil in the accumulation chamber R is blocked from being discharged toward the open end 10b.

Even in the case of the one-way valve 22A according to the modified example, the oil in the accumulation chamber R is prevented from being discharged to the open end 10b side of the main body cylinder 10 as in the case of the one-way valve 22A. However, inflow of oil from the open end 10b side into the accumulation chamber R is allowed.
As a result, oil can flow into the accumulator chamber R from the open end 10b side of the main body cylinder 10 through the through hole 23, so that the negative pressure state generated in the accumulator chamber R due to the inflowed oil is reduced. Can be eliminated or alleviated. Therefore, since the force F1 that pulls the plug 20 toward the one end (contact portion 10a) in the main body cylinder 10 is relaxed, the plug 20 moves together with the piston 11 toward one end (contact portion 10a) in the main body cylinder 10. This can be suitably prevented.

DESCRIPTION OF SYMBOLS 1 Accumulator 10 Main body cylinder 10a Contact part 10b Open end 11 Piston 11a Bottom part 11b Perimeter wall part 12 Spring 13 Oil path 14 Supply oil path 15 Orifice 16 Retainer 20 Plug 21 Boss part 21a Protrusion part 22, 22A One-way valve 23, 23A Through Hole 23a Through-hole portion 23b Ball housing portion 24 Ball 26 Valve body 26a Shaft portion 26b Locking portion 26c Cover portion R Accumulation chamber

Claims (3)

An accumulator provided in a hydraulic circuit for supplying hydraulic pressure to a friction engagement element of an automatic transmission,
A cylindrical body cylinder;
A piston provided to be movable in the axial direction of the main body cylinder in the main body cylinder;
A spring that biases the piston toward one end of the main body cylinder;
A plug fitted into the main body cylinder on the other end side of the main body cylinder, and a base end of the spring abutted;
A supply-side oil passage that communicates an oil passage that supplies hydraulic pressure to one of the frictional engagement elements and the inside of one end of the main body cylinder;
An oil passage that supplies hydraulic pressure to the other one of the frictional engagement elements and a back pressure side oil passage that communicates with the inside of the other end of the main body cylinder and has an orifice interposed therebetween,
The plug is provided with a through-hole penetrating in the axial direction of the main body cylinder,
An accumulator comprising a check valve that allows only flow from the outside of the main body cylinder into the main body cylinder through the through hole. The check valve is
2. The accumulator according to claim 1, wherein the accumulator is a ball provided so as to be movable in the axial direction within the through hole. The sliding resistance coefficient when the plug moves in the main body cylinder is α, the force required to move the plug is αF, and when the negative pressure state occurs on the plug side in the main body cylinder, the plug When the force acting on F1 is F1,
The accumulator according to claim 1 or 2, wherein a cross-sectional area of the through hole is set so as to satisfy a relationship of αF≥F1.

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