JPS61116158A - Control device of hydraulically operated steed change gear for vehicle - Google Patents

Abstract

PURPOSE:To eliminate unnecessary leakage of hydraulic coil from a pressure reducing valve, by releasing the operation of the pressure reducing valve when the hydraulic pressure downstream of an orifice disposed between a hydraulically engaging element and a shift valve exceeds a predetermined value. CONSTITUTION:There is provided a release means 21 for detecting the hydraulic pressure P3 downstream of an orifice 15 disposed in a seventh oil passage L7 which is communicated with a third shift stage hydraulic clutch C3, and for releasing the operation of a pressure reducing valve 20 when the hydraulic pressure P3 exceeds a predetermined value. The release means 21 is incorporated in the pressure reducing valve 20, and is composed of a pressure receiving surface 20C for pressing the valve rightward and an eighth oil passage L8 branched off from the seventh oil passage L7, for applying the hydraulic pressure P3 to the valve, and therefore, even in a low throttle valve opening degree range, if the pressure P3 increases due to damping action by an accumulator 17, exceeding the predetermined value, the operation of the pressure reducing valve 20 is released, so that the line pressure is led to the downstream side of the pressure reducing valve 20 without being decreased.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a hydraulic system equipped with a hydraulic engagement element that inputs line pressure obtained by regulating the discharge pressure of a hydraulic power source with a pressure regulating valve through a shift valve. The present invention relates to an actuated speed change type control device.

(Prior Art) Conventionally, this type of device has an orifice interposed in the oil passage between the hydraulic engagement element and the shift valve, and an orifice on the downstream side of the orifice in the oil passage in order to prevent the occurrence of shift shock. An accumulator is connected to the part to buffer sudden pressure changes in the hydraulic engagement element when switching the shift valve, and the back pressure of the accumulator is increased in accordance with an increase in the throttle opening of the engine, It is known to modulate the accumulator so as to provide a buffering effect on the high pressure side by increasing the throttle opening.

According to this, even if the hydraulic pressure required to engage the hydraulic engagement element changes depending on the throttle opening degree in relation to the transmitted torque,
The hydraulic pressure that causes the buffering effect also changes depending on the throttle opening, so the hydraulic engagement element is always engaged in the buffering area, but in the low throttle opening area, the hydraulic pressure that causes the buffering effect changes. As the pressure decreases and the pressure difference between the line pressure input to the orifice increases, the flow rate flowing into the accumulator through the orifice increases and the buffering time becomes shorter, resulting in the inconvenience that the accumulator cannot provide sufficient buffering effect. .

Therefore, in order to eliminate this inconvenience, the applicant of the present application previously proposed in Japanese Patent Application No. 58-39129 a pressure reducing valve that operates to reduce the line pressure from the pressure regulating valve and input it to the orifice. We have proposed a system that responds to the throttle opening of the engine and operates in the low opening range, thereby reducing the differential pressure at the orifice in the low opening range and ensuring a long buffer time.

(Problems to be Solved by the Invention) In the above-mentioned proposal by Hikari, when the throttle opening is in the low opening range, the hydraulic pressure on the downstream side of the orifice rises through the buffering action of the accumulator, causing the hydraulic engagement element to rise. Even after the engagement is completed, the pressure reducing valve continues to be kept in an operating state, which causes unnecessary leakage of pressure oil in the pressure reducing valve, which is undesirable. The object of the present invention is to provide an improved device of the above proposal which eliminates unnecessary leakage of pressure oil.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a hydraulic engagement element that inputs line pressure obtained by regulating the discharge pressure of a hydraulic power source with a pressure regulating valve via a shift valve. A hydraulically operated transmission for a vehicle, comprising an orifice in an oil passage between the hydraulic engagement element and the shift valve, and an accumulator connected to a portion of the oil passage downstream of the orifice. The back pressure of the accumulator is increased in accordance with an increase in the throttle opening of the engine, and a pressure reducing valve is provided which operates to reduce the line pressure from the pressure regulating valve and input it to the orifice, and the pressure reducing In a valve that responds to the throttle opening of the engine and operates in a low opening range,
The present invention is characterized in that a release means is provided that detects the oil pressure downstream of the orifice in the oil passage and releases the operation of the pressure reducing valve when the oil pressure rises to a predetermined value or more.

(Example) The present invention will be explained with reference to the illustrated embodiments.

Referring to FIG. 1, (1) is an engine, (2) is a driving wheel of a vehicle, and the output from the engine (1) is connected to the engine (1) via a fluid torque converter (3). The power is transmitted to the drive wheels (2) via a hydraulically operated transmission (4).

The transmission (4) has three forward speeds and one reverse speed, and has an input connected to the fluid torque converter (3).
4a) and the output shaft (4b) connected to the drive wheel (2), there is a forward transmission system (G1) (G2) for 1st to 3rd speed.
) (G3) and a reverse transmission system (GR), each of the hydraulic clutches (CI) for 1st to 3rd speeds, which are hydraulic engagement elements for each forward transmission system (G1) (G2) (G3) ( C2) (C3
) to intervene in each hydraulic clutch (C1) (C2) (
C3), each transmission system (G1) (G2) (
G3) is selectively established, and the reverse transmission system (
GR) is a 2-speed transmission system (G2) and a 2-speed hydraulic clutch (C
2) is shared, and the selector gear that selects both transmission systems (G2) (GR) (in the drawing 9, it is established by switching to the right reverse side. In the drawing, (6) is 1
A one-way clutch that intervenes in the speed transmission system (G1) operates to allow over-rotation on the output shaft (4b) side.

Each of the hydraulic clutches (C1, C2, and C3) is supplied and discharged with oil by a hydraulic circuit shown in FIG. 7)
, a pressure regulating valve (8) that regulates the discharge pressure of the hydraulic pressure source (7), "P" for parking, "R" for reverse, "N" for neutral, rDJ for automatic shifting, 2nd speed. “2” for holding
” manual valve (9) that can be switched between 5 positions, and a shift valve (IO) that is switched depending on the vehicle speed and throttle opening.
It is equipped with a servo valve (ltl) for forward/reverse switching that connects the selector gear (9) described above, and the t'D of the manual valve (9).
At the J position, the first oil passage (Ll) that inputs the line pressure from the pressure regulating valve (8) is connected to the second oil passage (Ll) connected to the shift valve (IQ).
2) so that oil is supplied to the 2nd and 3rd speed hydraulic clutches (C2) and (C3) through the shift valve 0G, and a second oil path is connected to the 1st speed hydraulic clutch (C1). (L
Oil is constantly supplied through the third oil passage (L3) branched from 2). Here, the shift valve 00 is the intermediate fourth shift valve.
A first valve (10-1) for 1st-2nd speed shifting on the upstream side and a second valve (10-1) for 2nd-3rd speed shifting on the downstream side are connected to each other via an oil passage (L4). 2), and the polyvalent (10-
1) At one end (10-2), that is, at the right end, there is a governor pressure from the governor valve (121) that corresponds to the vehicle speed, and at the left end, there is a first throttle valve (13-1) that controls the throttle opening of the engine (1). As the vehicle speed increases, the first valve (10-1) moves from the first gear position on the right side to the second gear position on the left side due to the governor pressure, and the second oil passage ([2 )
is connected to the fifth oil passage (shi5) on the outflow side of the second valve (10-2) via the fourth oil passage (L4), and the fifth oil passage (shi5) is connected to the fifth oil passage (shi5) on the outflow side of the second valve (10-2) at the rDJ position of the manual valve (9). Line pressure is input to the 2nd speed hydraulic clutch (C2) through the 6th oil passage (Shiro) connected to the 2nd speed hydraulic clutch (C2), and when the 1st speed is shifted up to 2nd speed and the vehicle speed further increases, the 2nd speed hydraulic clutch (C2) is connected to the 2nd speed hydraulic clutch (C2). (10-2) moves from the 2nd speed position on the right side to the 3rd speed position on the left side, and the 4th oil passage (L4) is connected to the 7th oil passage (L4) which connects from the 5th oil passage ([5) to the 3rd speed hydraulic clutch (C3). The fifth oil passage (L5) is switched and connected to the oil passage (Ll).
is connected to the first oil drain path (LOl), drains oil from the second speed hydraulic clutch (C2) and supplies oil to the third speed hydraulic clutch (C3), that is, inputs line pressure. Made it possible to shift up quickly.

Also, due to deceleration, the second valve (10-2) returns to the second speed position on the right side, and the fourth oil passage (S4) changes to the fifth oil passage (S4) as described above.
L5) and the seventh oil passage (Ll) are switchably connected to the second oil drainage passage (L02), so that oil is drained from the third-speed hydraulic clutch (C3) and oil is supplied to the second-speed hydraulic clutch (C2). done, 3
is downshifted from 1st gear to 2nd gear.

If the speed is further reduced, the first valve (10-1) returns to the first gear position on the right side, and the fourth oil passage (L4) becomes the third oil drain passage (L03).
The second gear hydraulic clutch (C2) is connected to drain the oil from the second gear hydraulic clutch (C2), and is downshifted from the second gear to the first gear.

The shift shock is particularly problematic here because the shift valve (
The gear shift is from 2nd to 3rd gear using the 2nd and 3rd gear hydraulic clutches (C2HC3) that input line pressure via IO, and the shift valve GG and 2nd gear hydraulic clutch (C2) are used to reduce shift shock. The fifth oil passage (L5) between the shift valve (I
The seventh oil passage (Ll) between G and the third-speed hydraulic clutch (C3)
), and each orifice G@ (15
Accumulators t'+e (171) for 2nd speed and 3rd gear are connected to the downstream part of 1, respectively, and each accumulator (Iea7) is connected to the throttle opening according to the throttle opening from the second throttle valve (13-2). Throttle pressure acts as back pressure, and thus the back pressure increases as the throttle opening increases, and the pressure change buffering effect of each of the accumulators as a"b is performed in different areas depending on the throttle opening. I did it like that.

Incidentally, the second-speed accumulator CIe was connected to the fifth oil passage (S5) via a manual valve (9) at its rDJ level.

In the drawing, ■a9 is each hydraulic clutch (C2) for 2nd and 3rd speed (
A one-way valve is shown that is installed in parallel with each of the orifices (1@(+51) in order to quickly drain oil from C3).

Then, the pressure reducing valve (2), which operates to reduce the line pressure from the pressure regulating valve (8) and input it to each orifice (115), is connected to the second oil passage (L2) upstream of the shift valve 00, for example.
The pressure reducing valve (1) is operated in the low opening range in response to the throttle opening.
To explain this in more detail, the pressure reducing valve (2) is constituted by a pressure regulating type valve that outputs hydraulic pressure according to the pressing force applied to one end, that is, the left end in the drawing, and as this pressing force, a spring (20a) is used.
and the throttle pressure from the second throttle valve (13-2), and in the low opening range of the throttle opening, as the throttle pressure decreases, this pushing force becomes the pushing force to the left of the valve (1) due to the line pressure. , the valve ■ moves to the left and the drain boat (
20b) was opened, and the output pressure of the valve (2) was reduced to below the line pressure in the low opening region as shown in the third figure. The above is not particularly different from the previous proposal, but
In the illustrated embodiment, in accordance with the features of the invention:
For example, the 7th oil passage (L) connected to the 3rd speed hydraulic clutch (C3)
l) orifice (+!i1 downstream hydraulic pressure (hereinafter P3
A release means (2) is provided which releases the operation of the pressure reducing valve (2) when P3 rises above a predetermined value by detecting the ■The pressure receiving surface (2
0c) and an 8th oil passage (L8) branched from the 7th oil passage (Ll) that applies P3 to this, and even in the low throttle opening range, P3 is connected to the accumulator (+7
If the pressure rises to a predetermined value or more through the buffering action of !, then the pressure-receiving areas at the right and left ends of the pressure reducing valve ■ are Sa, sb, and pressure-receiving surface Q!, respectively. If the area of Oc) is Sc, the line pressure is Pt, the throttle pressure is Pt1 and the force of spring (20a) is F, then
The pressure reducing valve (2) was moved to the right to close the drain boat 120b), that is, the operation of the pressure reducing valve (2) was released so that the line pressure was guided downstream without being reduced.

Here, 1st speed, 83rd speed, 2nd speed in the low throttle opening area
It is desirable to set Sc as small as possible so that the above-mentioned predetermined [PA] is sufficiently higher than the hydraulic pressure range that produces a buffering effect by the accumulator (17) when shifting from 3rd gear to 3rd gear. When the pressure is within the oil pressure range, the pressure reducing valve ■ is hardly affected by P3, and the buffer time can be secured as well as the previous proposal, and when downshifting from 3rd gear to 2nd gear, the pressure reducing valve At the start, the pressure reducing valve ■ is activated immediately, and the 2-speed hydraulic clutch (
The orifice (141) of the fifth oil passage (L5) connected to C3)
Even if the hydraulic pressure on the downstream side of the accumulator (hereinafter referred to as P2) increases to the hydraulic pressure range that produces the buffering effect of the accumulator (Ie), the pressure reducing valve ■ remains in the deactivated state and the effect of its operation cannot be obtained. It is also advantageous to prevent
In the illustrated embodiment, an orifice is inserted in the eighth oil passage (L8) to further delay the timing of deactivation of the pressure reducing valve (2) when shifting up to third gear, and A one-way valve is provided in parallel with the orifice (2), and when downshifting from 3rd gear, the pressure receiving surface (2
The working pressure to 0c) was quickly lowered so that the timing of the return to operation of the pressure reducing valve (2) would not be delayed.

(Function) The function of the present invention will be explained based on the above-mentioned embodiments with respect to a case where a shift from 2nd speed to 3rd speed is performed in a low throttle opening range. When shifting up to 3rd gear, P3 is boosted by the 11+ action of the accumulator (17+),
Here, in the low throttle opening range, a buffering effect is provided on the low pressure side, and in this case, if the line pressure is input directly to the orifice ae, the differential pressure at orifice 09 that occurs during the buffering effect will become too large and the buffering time will be shortened. However, in this area, the line pressure is reduced by the operation of the pressure reducing valve (2) and inputted to the orifice 119, so the differential pressure is reduced and a sufficient buffer time is secured, allowing the 3rd speed hydraulic clutch (C3) to operate smoothly. engaged. The above is not particularly different from the operation of the above-mentioned proposal, but according to the present invention, when P3 rises to a predetermined value or more after undergoing a buffering action, the pressure reducing valve ■ is activated by the release means ■.
When cruising in 3rd gear even when the throttle is in the low l7i 1 degree range, the line pressure is directly input to the 3rd gear hydraulic clutch (C3) without unnecessary leakage of pressure oil using the pressure reducing valve ■. This increases the engagement force.

Also, when downshifting to 2nd gear due to deceleration, P3
is stepped down and P2 is stepped up, and the accumulator Ge provides a buffering effect against the rise in P2, but in this case P3
When the pressure is lowered, the pressure reducing valve (2) is returned to operation, and the second speed hydraulic clutch (C2) is smoothly engaged with a sufficient buffer time as described above.

In the above embodiment, since cruising for a relatively long time in the low throttle opening range is carried out exclusively in the 3rd gear,
Only P3 was used as the hydraulic pressure for the release means (■), but considering that there is a possibility of a relatively long two-way retraction in the low throttle opening range, for example, it may be applied to the right side of the pressure reducing valve (■). A pressure receiving surface separate from the pressure receiving surface (20c) to be pressed may be formed, P2 may be applied to this surface, and P3 and 22 may be used together as the hydraulic pressure for the release means (2).

(Effects of the Invention) As described above, according to the present invention, after the hydraulic engagement element is engaged through the buffering action of the accumulator, the operation of the pressure reducing valve is released, and the pressure oil is released from the pressure reducing valve after engagement. This has the effect of eliminating unnecessary leakage and increasing the engagement force of the hydraulic engagement element.

[Brief explanation of drawings]

FIG. 1 is a diagram of an example of a transmission to which the device of the invention is applied, FIG. 2 is a circuit diagram of an example of the device of the invention, and FIG. 3 is a diagram showing the characteristics of a pressure reducing valve. (4)...Transmission (C1) (C2) (C3)...Hydraulic clutch (hydraulic engagement element) (7)...Hydraulic pressure source (8)...Pressure regulating valve (IO...Shift Valve (L5) (L7)... Oil path α4) (+51... Orifice a9a7)... Accumulator ■... Pressure reducing valve ■... Pressure reducing means

Claims (1)

[Claims] A hydraulically actuated transmission for a vehicle includes a hydraulic engagement element that inputs line pressure obtained by regulating the discharge pressure of a hydraulic power source with a pressure regulating valve through a shift valve, the hydraulic engagement element and the shift An orifice is interposed in the oil passage between the valve and the oil passage, and an accumulator is connected to a downstream portion of the orifice, so that the back pressure of the accumulator is increased in accordance with the increase in the throttle opening of the engine. Further, a pressure reducing valve is provided that operates to reduce the line pressure from the pressure regulating valve and input it to the orifice, and the pressure reducing valve is operated in a low opening range in response to the throttle opening of the engine. for a vehicle, characterized in that it is provided with a release means that detects the oil pressure downstream of the orifice in the oil passage and releases the operation of the pressure reducing valve when the oil pressure rises to a predetermined value or more. Control device for hydraulically operated transmission.