JPS6234979B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a low-speed hydraulic engagement element and a high-speed hydraulic engagement element that respectively establish a low-speed transmission system and a high-speed transmission system provided in a transmission, and can be freely switched between a low-speed position and a high-speed position. The present invention relates to a control device for a hydraulically operated transmission for a vehicle, in which pressure oil from a hydraulic source is supplied via a shift valve in a switchable manner.

Conventionally, this type of device has an orifice installed in the oil drain passage installed to drain oil from the low-speed hydraulic engagement element when the shift valve is switched to the high-speed position, and an orifice connected in parallel to this to increase the throttle opening of the engine. A drain oil control valve that is pressed toward the closing side is interposed, and there is a difference in pressure drop characteristics due to drain oil of the low-speed hydraulic engagement element between speed changes in the middle and high opening range of the throttle and speed changes in the low opening range. It is known to add .

To explain this in more detail, in the comparatively high opening range of the throttle, the engine torque becomes large, and the engagement pressure required to engage the high-speed hydraulic engagement element becomes high. However, in this region, the oil drain control valve is shifted to the closed side, and the resistance of the low-speed hydraulic engagement element to oil drain increases, causing a relatively gradual drop in the oil pressure of the low-speed hydraulic engagement element. Its release is also delayed, and the engine is prevented from racing due to the mutual engagement of both hydraulic engagement elements. In addition, in a comparatively low opening range of the throttle, the engagement pressure of the high-speed hydraulic engagement element decreases due to the decrease in engine torque, and the engagement of the high-speed hydraulic clutch during gear shifting is accelerated. Since the valve is moved to the open side and the oil drainage resistance is reduced, the hydraulic pressure of the low-speed hydraulic engagement element is lowered relatively rapidly and its release is accelerated, and co-engagement is restricted and the so-called engine stall occurs. is prevented.

However, in this case, even if the pressure of the high-speed hydraulic engagement element is increased to a predetermined engagement pressure, the low-speed hydraulic engagement element is not released almost synchronously, and a relatively large drag due to the residual pressure of the low-speed hydraulic engagement element occurs. This has the disadvantage that torque is generated and engine braking tends to occur.

An object of the present invention is to provide a device that eliminates such inconveniences, and includes a low-speed hydraulic engagement element and a high-speed hydraulic engagement element that respectively establish a low-speed transmission system and a high-speed transmission system provided in a transmission. an oil drain path which is switchably supplied with pressure oil from a hydraulic source via a shift valve which can be switched between a low speed position and a high speed position, and which is connected to a low speed hydraulic engagement element at the high speed position of the shift valve. and in which an orifice is interposed in the oil drain passage, and an oil drain control valve that is pushed toward the closing side by receiving throttle pressure at one end in parallel with the orifice as the throttle opening of the engine increases, a variable orifice valve having a throttle position in the middle in response to a predetermined set pressure at the other end corresponding to the throttle opening of the hydraulic pressure supplied to the high-speed hydraulic engagement element so as to return the oil drain control valve to the open side; It is characterized by being composed of.

Next, embodiments of the present invention will be explained with reference to attached drawings. In the drawings, reference numeral 1 denotes a transmission that performs three forward speeds and one reverse speed, and the transmission 1 includes an input shaft 1a connected to an engine 2 via a torque converter 3;
A transmission system G1, G2, G3 for forward speeds 1 to 3 and a reverse transmission system GR are provided between the output shaft 1b connected to the drive wheels 4 of the vehicle via a differential gear 5. 1st to 3rd speed hydraulic clutches C1, which are hydraulic engagement elements, are connected to each transmission system G1, G2, G3.
C2 and C3 were intervened.

The reverse transmission system GR shares the 2nd speed transmission system G2 and the 2nd speed hydraulic clutch C2, and both transmission systems G2 and GR are connected to the selector gear 6 on the output shaft 1b.
It was established selectively via .

In the drawing, 7 is a one-way clutch interposed in the first-speed transmission system G1, which operates to allow over-rotation of the output shaft 1b. Each of the hydraulic clutches C1, C
For example, the oil supply and discharge of C3 is controlled by a hydraulic circuit shown in FIG. “R” for neutral, “N” for neutral,
A manual valve 9 that can be switched to five positions: "D" for automatic gear shifting and "2" for holding second gear; a shift valve 10 that is switched depending on the vehicle speed and throttle opening; and the aforementioned selector gear. When the manual valve 9 is in the "D" position, the first oil path L1 leading to the hydraulic power source 8 is connected to the second oil path L1 leading to the shift valve 10.
2, and the oil passage clutches C2 and C3 for the second and third speeds are supplied with oil through the shift valve 10.

The 1st speed hydraulic clutch C1 is always supplied with oil via the 3rd oil path L3 branched from the 2nd oil path L2. As the clutch C2 is refueled, its engagement force is gradually strengthened and the rotational speed of the output shaft 1b exceeds the speed of the first speed transmission system G1 due to torque transmission through the second speed transmission system G1. 1st speed transmission system G1 by clutch 7
Torque transmission via the gearbox is automatically stopped and no shift shock occurs.

Therefore, the problem with the shift shock is that the shift valve 10 causes the second-speed hydraulic clutches C2 to C3 to
This is a shift between 2nd and 3rd speeds that changes the oil supply to the hydraulic clutch C3, and this point will be described in detail below.

The shift valve 10 includes a first valve 10-1 for shifting between 1st and 2nd speeds on the upstream side and a first valve 10-1 for shifting between 2nd and 3rd speeds on the downstream side, which are connected to each other via an intermediate fourth oil passage L4. 2 valves 10-2, each valve 1
The governor pressure corresponding to the vehicle speed from the governor valve 12 is applied to one end of 0-1 and 10-2, that is, the right end, and the first one is applied to the left end.
Throttle pressure corresponding to the throttle opening degree from the throttle valve 13-1 is applied to the first valve 10-1.
1 moves from the first speed position on the right side to the second speed position on the left side, and the second oil passage L2 is connected to the fifth oil passage L5 on the outflow side of the second valve 10-2 via the fourth oil passage L4. , pressure oil from the hydraulic source 8 is supplied to the second-speed hydraulic clutch C2 via the sixth oil passage L6 connected to the fifth oil passage L5 at the "D" position of the manual valve 9,
When a shift from 1st to 2nd gear is performed and the vehicle speed further increases, the second valve 10-2 moves from the 2nd gear position on the right side to the 3rd gear position on the left side, and the fourth oil passage L4 becomes the fifth oil passage. L5 is switched and connected to a seventh oil passage L7 leading to the third-speed hydraulic clutch C3, and the fifth oil passage L5 is a drain oil passage.
It is connected to LD to drain oil from the 2nd speed hydraulic clutch C2 and supply oil to the 3rd speed hydraulic clutch C3, so that a shift from 2nd speed to 3rd speed can be performed. Then, an orifice 14 and a drain oil control valve 15 that is pressed to the closing side as the throttle opening increases are interposed in the oil drain path LD, and the oil drain control valve 15 is inserted in parallel with the orifice 14 and is pressed toward the closing side as the throttle opening increases. The pressure reduction characteristic of the hydraulic pressure of the hydraulic clutch C2, that is, the second speed pressure, is made to have a slow or fast difference depending on the throttle opening.

In the illustrated example, an accumulator 16 for buffering changes in the third-speed pressure is connected to the seventh oil passage L7 leading to the third-speed hydraulic clutch C3.
The throttle pressure from the second throttle valve 13-2 acts on the throttle valve 6 as a back pressure, and as the engagement pressure of the third-speed hydraulic clutch C3 increases due to an increase in the throttle opening, the accumulator 16 is set to the high pressure side. The modulation was made so as to obtain a buffering effect of .

In the drawing, reference numeral 17 indicates an accumulator connected to the 2-speed hydraulic clutch C2 at the "D" position of the manual valve 9, and the accumulator 17 also has a second throttle valve 13 similar to the accumulator 16 described above.
Throttle pressure from -2 is applied. Although the above is not particularly different from the conventional type described above, according to the present invention, the hydraulic pressure supplied to the third-speed hydraulic clutch C3 increases to a predetermined set pressure according to the throttle opening, and almost synchronously therewith. The drain oil control valve 15 is returned to the open side.

The drain oil control valve 15 has a second throttle valve 13 at one end, that is, the right end, as clearly shown in FIG. 3, for example.
-2 is applied via the eighth oil passage L8, and is pressed toward the closing side against the spring 15a.
The oil pressure supplied to the quick hydraulic clutch C3 is applied via the ninth oil passage L9 branched from the seventh oil passage L7, and the oil drainage control valve 15 is made to be a variable orifice valve with an intermediate throttle position. In the annular groove on the outer periphery of the oil control valve 15, an inclined part 18 is formed by tapering or double chamfering over the entire circumference as shown in the third figure, or a stepped part 19 is formed as shown in the fifth figure. The degree of throttling of the valve 15 is sequentially changed as shown in FIG. 4 or FIG. 6, so that the degree of slowness and rapidity of the pressure drop characteristic is sequentially changed in accordance with changes in the throttle opening.

Next, its operation will be explained based on the characteristic diagram of FIG. 7 showing changes in the 2nd speed pressure and the 3rd speed pressure during a shift from 2nd speed to 3rd speed.

In the case of a conventional oil drain control valve, the 2nd speed pressure depends on the throttle opening, for example, if it is a medium opening of about 5/8, it will be as shown by line A', and if it is a low opening of about 2/8, it will be as shown by line A'. Ba
The pressure decreases as shown by line B', and the 3rd speed pressure is increased to the buffer area by the above-mentioned accumulator 16 as shown by the X-ray when the opening is medium, and as shown by the Y when the opening is low, and the 3rd speed hydraulic clutch C3 is Even after the clutch is fully engaged, a relatively large second speed pressure remains, causing unnecessary co-engagement with the second speed hydraulic clutch C2, resulting in a slight engine braking.

On the other hand, according to the illustrated embodiment, the drain oil control valve 15 is pushed to the opening side by the increase in the third speed pressure, and when the third speed pressure exceeds a predetermined set pressure, the valve 15 is fully opened and the second speed Pressure drops rapidly.

Here, the set pressure is determined by the balance with the pressing force toward the closing side due to the throttle pressure, and changes depending on the throttle opening. With the rise to P ₁ ,
In addition, at a low opening, the rise to the lower pressure P ₂ causes a sudden drop in the 2nd speed pressure almost synchronously with the rise, and the pressure drop characteristics are as shown by the lines A and B in Fig. 7. At either opening degree, unnecessary co-inclusion due to the residual pressure of the 2nd speed pressure after the 3rd speed pressure has increased to the buffer region is prevented.

Further, the sudden drop in the second speed pressure is applied after the third speed pressure has risen to the high set pressure corresponding to the increase in throttle opening, so that the engine does not start up.

Further, in the above embodiment, attention is paid to the shift from 2nd speed to 3rd speed, and the 2nd speed hydraulic clutch C2 is a low speed hydraulic engagement element,
Although the third-speed hydraulic clutch C3 has been described as a high-speed hydraulic engagement element, it is needless to say that the present invention is not limited to this.

As described above, according to the present invention, the oil drain control valve, which receives the throttle pressure accompanying the increase in the throttle opening of the engine at one end and is pushed toward the closing side, has a high speed control valve at the other end so as to return it to the opening side. The hydraulic pressure of the low-speed hydraulic engagement element is determined by a variable orifice valve with a throttle position in the middle in response to a predetermined set pressure depending on the throttle opening of the hydraulic pressure supplied to the hydraulic engagement element. When the hydraulic pressure supplied to the high-speed hydraulic engagement element rises to the set pressure, the hydraulic pressure is suddenly lowered almost synchronously with the increase, and the low-speed hydraulic engagement element is engaged after the high-speed hydraulic engagement element is engaged, without causing the engine to start up. Since it is possible to eliminate unnecessary co-engagement with the low-speed hydraulic engagement element, it is possible to smoothly shift gears without producing drag torque due to residual pressure of the low-speed hydraulic engagement element.

[Brief explanation of the drawing]

FIG. 1 is a diagram of an example of a transmission to which the device of the present invention is applied, FIG. 2 is a hydraulic circuit diagram of an example of the device of the present invention,
Figure 3 is a circuit diagram of the main part showing the oil drain control valve, Figure 4 is a line diagram showing the characteristics of this oil drain control valve, and Figure 5 is a circuit diagram of the main part showing a modification of the oil drain control valve. , FIG. 6 is a diagram showing the characteristics of this oil drain control valve, and FIG. 7 is a diagram showing the pressure drop characteristics and pressure increase characteristics of each hydraulic engagement element during gear shifting. 1... Transmission, 8... Hydraulic source, 10... Shift valve, 14... Orifice, 15... Oil drain control valve, C2... 2nd speed hydraulic clutch (low speed hydraulic engagement element), C3... 3 High-speed hydraulic clutch (high-speed hydraulic engagement element), LD...Drainage path.

Claims (1)

[Claims] 1. A low-speed hydraulic engagement element and a high-speed hydraulic engagement element, which respectively establish a low-speed transmission system and a high-speed transmission system provided in a transmission, are supplied with hydraulic power from a hydraulic source via a shift valve that can be freely switched between a low-speed position and a high-speed position. In addition to supplying pressurized oil in a switchable manner, an oil drain path is provided which is connected to the low-speed hydraulic engagement element at the high speed position of the shift valve, and an orifice and an engine throttle opening are connected to the oil drain path in parallel with the orifice. and a drain oil control valve that receives throttle pressure accompanying an increase in temperature at one end and is pushed toward the closing side. 1. A control device for a hydraulically actuated transmission for a vehicle, comprising a variable orifice valve having a throttle position in the middle and receiving a predetermined set pressure according to the throttle opening of oil pressure supplied to an element.