JP2001099281A - Hydraulic control device for transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control device for a transmission capable of adapting a solenoid valve being of a type used in oil, in a hydraulic control device being of a type where a hydraulic block is situated at the upper part of other part than a transmission. SOLUTION: A hydraulic control device 10 for a transmission to switch speed change according to a feed and discharge of an oil pressure to and from a friction engaging element comprises a hydraulic block 11 disposed at the upper part of a transmission and provided at an internal part with an oil passage communicating with a pressure regulating valve 20 and the friction engaging element; an oil cover 15 situated between the hydraulic block 11 and the transmission and storing oil; and a solenoid valve 13 situated in a state to be immersed in oil in the oil cover 15 and controlling an oil pressure in the oil passage according to an energizing current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for controlling a hydraulic pressure for switching a speed change of a transmission.

[0002]

2. Description of the Related Art A hydraulic control device for a transmission is generally formed in a lower portion of the transmission inside the transmission. In such a configuration, a solenoid valve for controlling the hydraulic pressure is immersed in an oil pan. The solenoid valve is used in a state of being used in oil.

In addition to the above-described configuration, there is a type in which a hydraulic block of a hydraulic control device is formed on an upper portion of a transmission due to a mounting space and a layout, but in this configuration, a solenoid valve for controlling a hydraulic pressure has an atmospheric pressure. Therefore, a solenoid valve of an aerial use type is used.

[0004]

However, the solenoid valve of the air use type requires a sealing material for preventing intrusion of water from the outside. Since it is exposed to the atmosphere, it is used in the oil type. The configuration becomes complicated because the heat radiation is inferior to that of the above, and the valve itself needs to be subjected to rust prevention treatment.

Accordingly, the present invention has been made in view of the above problems,
A technical object of the present invention is to provide a hydraulic control device for a transmission in which a hydraulic block of a type in which a hydraulic block is disposed above a transmission can employ a solenoid valve of a type used in oil.

[0006]

According to a first aspect of the present invention, there is provided a hydraulic control device for a transmission for switching gears in accordance with supply / discharge of hydraulic pressure to / from a friction engagement element. A hydraulic block disposed at the top and having an oil passage communicating with the pressure regulating valve and the friction engagement element therein;
An oil cover provided between the hydraulic block and the transmission for storing oil, and a solenoid disposed in a state of being immersed in the oil in the oil cover and capable of controlling the oil pressure in the oil passage in accordance with a current supplied thereto And a valve.

According to a second aspect of the present invention, in the first aspect, the oil cover is provided with a discharge portion for discharging the oil when a predetermined amount or more of oil is stored from a state where the entire solenoid valve is immersed in the oil. That is.

According to a third aspect of the present invention, in the first or second aspect, the oil cover is arranged at a position where oil drained from the pressure regulating valve can be stored.

According to the first to third aspects, the solenoid valve is used in a state where it is immersed in oil in the oil cover, so that a solenoid valve that is used in oil can be used. Therefore, in the hydraulic control device in which the hydraulic block is disposed above the transmission, the configuration of the solenoid valve can be simplified.

According to a fourth aspect of the present invention, in the first aspect, the hydraulic control device includes a braking friction engagement element that generates a braking force by engagement, and an axial displacement that opposes the braking friction engagement element. A possible piston, a pressure receiving chamber formed between the piston and the braking friction engagement element, and a biasing member for biasing the piston toward the braking friction engagement element are provided to the pressure receiving chamber. As the hydraulic pressure increases, the piston moves in the direction of weakening the engagement force of the braking friction engagement element against the biasing force of the biasing member, and as the hydraulic pressure supplied to the pressure receiving chamber decreases, the bias of the biasing member decreases. That is, the piston moves in the direction of increasing the engagement force of the braking friction engagement element by the force.

According to the fourth aspect, when the hydraulic pressure is supplied to the pressure receiving chamber, the braking force is weakened, and when the hydraulic pressure is not supplied, the biasing member moves the piston in the direction of engaging the frictional engagement element for braking. By doing so, the braking force is strengthened. Therefore, the frictional engagement element for braking is engaged when the transmission in which the hydraulic pressure in the hydraulic pressure control device becomes 0 is inactive, and the frictional engagement element for braking is engaged when the transmission is inactive (for example, in a vehicle). In this case, it can be used as a braking device during parking.

According to a fifth aspect of the present invention, in the first aspect, the pressure regulating valve is a spool valve including a cylinder forming a low pressure port, a high pressure port, and a drain port, and a valve spool slidable in the cylinder. On one end side of the land capable of shutting off the high pressure port and the low pressure port, an auxiliary land is provided at a predetermined distance in the axial direction with respect to the land and having substantially the same shape as the land with respect to a plane perpendicular to the axial direction. Means that a through hole is formed at a predetermined distance between the auxiliary land and the land, and a communication hole communicating with the drain port and communicating with the through hole is formed.

According to the fifth aspect, the oil leaking from the high pressure port to the low pressure port in a state where the high pressure port is blocked by the land flows into the minute space between the land and the auxiliary land, and is drained from the through hole through the communication hole. It becomes possible to discharge to the port. Therefore, there is no need to provide a drain port between the high pressure port and the low pressure port in order to discharge oil leakage from the high pressure port side, and the axial length of the spool valve is reduced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view of a transmission hydraulic control device 10 according to the first embodiment. 1st Embodiment demonstrates the case where the hydraulic control apparatus 10 is used for the transmission of a forklift.

FIG. 1 shows an upper portion of a housing 12 for accommodating a transmission (not shown) in the hydraulic control device 10, and a transmission including a frictional engagement element is configured at the lower portion of FIG. I do.

The hydraulic control device is a device for switching the supply and discharge of hydraulic pressure to and from the friction engagement element in order to switch the speed of the transmission. In FIG. 1, the hydraulic control device communicates with the pressure regulating valve 20 and the friction engagement element. A hydraulic block 11 having an oil passage inside is fixed to an uppermost portion of the housing 12 with a bolt 14. A linear solenoid valve 13 that operates to switch the hydraulic pressure in the hydraulic control device is provided below the hydraulic control device, and a pressure regulating valve in the hydraulic control device is controlled by controlling a current supplied to the linear solenoid valve 13. 2
The hydraulic pressure is switched by a valve such as 0. The control of energization of the linear solenoid valve 13 is performed by an electronic control unit (not shown). An oil cover 15 for storing oil drained from a pressure regulating valve 20 in the hydraulic block 11 as shown by an arrow in FIG. 1 is fixed between the hydraulic block 11 and the transmission with bolts 16. The valve 13 is connected to the oil 1 in the oil cover 15.
7 so as to be immersed therein.

As shown in FIG. 1, since the linear solenoid valve 13 is immersed in oil 17, even in a vehicle in which the hydraulic block 11 is disposed above the transmission, the linear solenoid valve 13 is of the aerial use type. It is not necessary to use a solenoid valve.
Can be adopted, so that the apparatus can be simplified and the cost can be reduced.

The oil cover 15 is provided with a discharge portion 15a for discharging oil when a predetermined amount or more of oil is stored from a state in which the entire linear solenoid valve 13 is immersed in oil. The oil discharged from the discharge portion 15a is stored in an oil pan provided at the bottom of the housing 12, pumped up by a pump, and
1.

Next, the pressure regulating valve 20 in the hydraulic block 11 will be described with reference to FIG. The pressure regulating valve 20 includes a low pressure port 21a, a high pressure port 21b, and an output port 21c.
And cylinder 2 forming drain ports 21d and 21e
1 and a valve spool 22 slidable in the cylinder 21
, And the output of oil to the high-pressure port 21b, the low-pressure port 21a, or the drain ports 21d and 21e is switched in accordance with the position of the valve spool 22. The valve spool 22 is urged leftward in the figure by a spring 23, and each port is blocked or communicated depending on the position of a land 22A formed on the valve spool 22. In the present embodiment, the high pressure port 2 formed on the valve spool 22
An auxiliary land 22B having the same diameter as the land 22A is formed on the low pressure port 21a side of the land 22A that regulates the supply of oil to the low pressure port 21a and the land 22A at a small axial distance from the land 22A. Land 22A and auxiliary land 2
In the minute interval between 2B, the through hole 22a is perpendicular to the axis.
The through hole 22a communicates with the drain port 21e through a communication hole 22b which is a blind hole formed in the axial direction from the right end of the valve spool 22 in the drawing.
According to this configuration, the high pressure port 21 is provided by the land 22A.
Oil that leaks from the high pressure port 21b to the low pressure port 21a while the b is shut off flows into the minute gap between the land 22A and the auxiliary land 22B as shown by the arrow in FIG. Through the drain port 21e. Therefore, there is no need to provide a drain port between the high pressure port 21b and the low pressure port 21a in order to discharge oil leakage from the high pressure port 21b side, and the axial length of the pressure regulating valve 20 can be reduced. .

Next, the auxiliary brake in the forklift of this embodiment will be described with reference to the hydraulic circuit diagram of FIG. FIG. 3 is a diagram showing a configuration related to an auxiliary brake of the hydraulic circuit. In a forklift, an engaging friction element for forward / backward movement and braking for vehicle speed control are provided so that the target vehicle speed determined by the map from the opening of the accelerator pedal is obtained at any engine speed determined by the opening of the cargo handling lever during traveling and cargo handling. The engagement friction element is hydraulically controlled.
At this time, the auxiliary brake is a mechanism that hydraulically controls the braking engagement friction element so that the forklift reaches the target vehicle speed.

The auxiliary brake 30 includes a braking friction engagement element 31 that generates a braking force of the forklift when engaged,
A piston 32 opposed to the braking friction engagement element 31 and capable of being displaced in the axial direction; a coil spring 33 serving as an urging member for urging the piston 32 toward the braking friction engagement element 31; Braking friction engagement element 31
As the supplied hydraulic pressure increases, the piston 32 moves in a direction to reduce the engaging force of the braking friction engagement element 31 against the urging force of the coil spring 33, and the supplied hydraulic pressure decreases. A pressure receiving chamber 34 is provided, in which the piston 32 moves in a direction in which the engagement force of the braking friction engagement element 31 is increased by the urging force of the coil spring 33 as the height decreases.

In this embodiment, as shown in FIG. 3, the braking force of the auxiliary brake 30 is generated by the urging force of the coil spring 33. When the oil pressure in the pressure receiving chamber 34 is increased, the piston 32
When the hydraulic pressure in the pressure receiving chamber 34 is reduced, the piston 32 moves when the hydraulic pressure in the pressure receiving chamber 34 is lowered by weakening the pressing force of the braking friction engagement element 31 by the piston 32 by moving against the urging force of the piston 32. The force against the urging force of the coil spring 33 is weakened, the pressing force of the piston 32 on the frictional engagement element 31 for braking is increased, and the braking force of the auxiliary brake 30 is increased. According to this configuration, even when the hydraulic pressure in the hydraulic circuit becomes zero when the engine is stopped, the braking force of the auxiliary brake 30 is ensured by the urging force of the coil spring 33. It can be used as a brake. Therefore, there is no need to newly provide a parking brake other than the auxiliary brake, and the hydraulic circuit configuration is simplified.

The entire hydraulic circuit including the auxiliary brake according to the present embodiment is configured as shown in FIG. The oil stored in an oil pan 41 provided at the bottom of the housing 12 is pumped up by an oil pump 42 to generate oil pressure, and the forward frictional engagement element 4 is transmitted from a regulator valve 43 via clutch control valves 45A and 45B.
6, transmitted to the reverse engagement friction element 47. It should be noted that hydraulic pressure fluctuations in the oil passages between the linear solenoid valves 13A, 13B and the clutch control valves 45A, 45B are configured to be absorbed by the accumulators 48A, 48B.
5B is controlled by hydraulic pressure from the reducing valves 44A, 44B and the linear solenoid valves 13A, 13B. The hydraulic pressure is transmitted from the regulator valve 43 to the braking engagement friction element 31 via the brake control valve 49. The brake control valve 49 is controlled by hydraulic pressure from the reducing valve 44C and the linear solenoid valve 13C. Further, hydraulic pressure is also supplied to the torque converter 51 via the lock-up control valve 50. Here, FIG.
The linear solenoid valves 13A, 13B and 13C correspond to the linear solenoid valve 13 shown in FIG. 1, and the clutch control valves 45A and 45 shown in FIG.
45B corresponds to the spool valve 20 shown in FIG. In FIG. 4, since the configuration of the valve is shown in a simplified manner, the port and land shape are different from those in FIG. 2, but the same valve is actually used in the drawing.

Although the embodiment of the present invention has been described above, the present invention is not intended to be limited to the above-described embodiment, but may be of any form according to the gist of the present invention. Obviously, the present invention may be applied to vehicles other than forklifts.

[0025]

According to the structure of the present invention, since the solenoid valve is immersed in oil in the oil cover, a solenoid valve used in oil can be used.
Therefore, in the hydraulic control device of the type arranged above the transmission, the configuration of the solenoid valve can be simplified.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a transmission hydraulic control device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a pressure regulating valve according to the present embodiment.

FIG. 3 is a hydraulic circuit diagram showing a configuration relating to an auxiliary brake in the present embodiment.

FIG. 4 is a hydraulic circuit diagram of a hydraulic control device according to the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Hydraulic control device 11 ... Hydraulic block 12 ... Housing 13 ... Linear solenoid valve 14 ... Bolt 15 ... Oil cover 20 ... Pressure regulating valve 21 ... Cylinder 22. ..Valve spool 23 ・ ・ ・ Spring 30 ・ ・ ・ Auxiliary brake 31 ・ ・ ・ Brake engagement friction element 32 ・ ・ ・ Piston 33 ・ ・ ・ Coil spring 34 ・ ・ ・ Pressure receiving chamber 41 ・ ・ ・ Oil pan 42 ・..Oil pump 43 ・ ・ ・ Regulator valve 44A, 44B, 44C ・ ・ ・ Reducing valve 45A, 45B ・ ・ ・ Clutch control valve 46 ・ ・ ・ Friction engagement element for forward travel 47 ・ ・ ・ Fast engagement friction for reverse travel Element 48A, 48B: Accumulator 49: Brake control valve 50: Lock-up control Lube 51 ... torque converter

Claims (5)

[Claims] 1. A hydraulic pressure control device for a transmission that switches a shift according to the supply and discharge of hydraulic pressure to and from a friction engagement element, wherein the hydraulic pressure control device is disposed at an upper portion of the transmission and has an internal pressure regulating valve and the friction. A hydraulic block having an oil passage communicating with the engagement element, an oil cover provided between the hydraulic block and the transmission for storing oil, and arranged in a state of being immersed in oil in the oil cover. And a solenoid valve capable of controlling the oil pressure in the oil passage in accordance with the energizing current. 2. The oil cover according to claim 1, wherein the oil cover is provided with a discharge portion for discharging oil when a predetermined amount or more of oil is stored in a state where the entire solenoid valve is immersed in oil. The hydraulic control device for a transmission according to claim 1. 3. The hydraulic control device according to claim 1, wherein the oil cover is disposed at a position where oil drained from the pressure regulating valve can be stored. 4. The hydraulic control device, comprising: a braking friction engagement element that generates a braking force by engagement; a piston opposed to the braking friction engagement element and axially displaceable; A pressure receiving chamber formed between the frictional engagement element for braking, and a biasing member for biasing the piston toward the frictional engagement element for braking, and a hydraulic pressure supplied to the pressure receiving chamber. Becomes higher, the piston moves in a direction to weaken the engagement force of the braking friction engagement element against the urging force of the urging member, and the urging force decreases as the hydraulic pressure supplied to the pressure receiving chamber decreases. 2. The hydraulic control device for a transmission according to claim 1, wherein the piston is moved in a direction to increase the engagement force of the braking friction engagement element by a biasing force of a member. 5. The high pressure port and the low pressure port of the valve spool, wherein the pressure regulating valve is a spool valve including a cylinder forming a low pressure port, a high pressure port, and a drain port, and a valve spool slidable in the cylinder. On one end side of the land capable of shutting off the land, an auxiliary land is provided at a predetermined distance in the axial direction from the land and having substantially the same shape as the land with respect to a plane perpendicular to the axial direction. The auxiliary spool is provided on the valve spool. 2. The hydraulic control of a transmission according to claim 1, wherein a through hole is formed at a predetermined distance between the lands and the land, and a communication hole communicating with the drain port and communicating with the through hole is formed. apparatus.