JPH0457899B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic control device for an automatic transmission for a vehicle.

[Prior Art] Conventionally, during an ND shift in an automatic transmission for a vehicle, hydraulic pressure is supplied from a hydraulic control device to a hydraulic servo of an input clutch of the transmission, and the input clutch is engaged. The engagement oil path of the clutch is equipped with a flow control valve with a check valve and an accumulator to relieve the shift shock during ND shifting, so that the hydraulic pressure applied to the hydraulic servo of the input clutch acts slowly. The engagement hydraulic pressure was controlled to lengthen the engagement time of the clutch.

[Problems to be Solved by the Invention] However, in the above configuration, if the ND shift is performed in a normal state of idling (transmission input is high rotation), when the transmission input is high rotation, the low rotation Since the engagement torque of the input clutch is greater than in the case where the input clutch is engaged, the engagement time of the input clutch is longer. As a result, the input clutch is subject to severe wear, causing problems such as burnout of the input clutch and its durability.

Therefore, the present invention not only relieves the shift shock during ND shifting, but also
Prevents excessive wear and burnout of the transmission input clutch that occurs during D-shift,
The object of the present invention is to provide a hydraulic control device for a vehicle automatic transmission whose durability is ensured.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a hydraulic source, a regulator valve that regulates the hydraulic pressure from the hydraulic source to line pressure, and a throttle pressure that adjusts the throttle pressure according to the throttle opening. A hydraulic control device for an automatic transmission for a vehicle, which is comprised of a throttle valve that generates a throttle valve, a manual valve that manually switches the gear range, and a hydraulic servo for a clutch that engages when the manual valve is shifted from a neutral position to a forward position. wherein an accumulator is interposed in a first oil passage communicating between the manual valve and the hydraulic servo when the manual valve is shifted from a neutral position to a forward position, and a second oil passage bypasses the first oil passage; oil passages are arranged in parallel, a control valve is interposed in the second oil passage,
The control valve inputs a throttle signal from the throttle valve, and when the signal is greater than or equal to a predetermined value, communicates with the control valve and communicates the manual valve with the hydraulic servo via the second oil path, The control valve is also cut off when the signal is below a predetermined value.

The present invention also includes a hydraulic source, a regulator valve that regulates the hydraulic pressure from the hydraulic source to line pressure, a throttle valve that generates a throttle pressure according to the throttle opening, and a manual valve that manually switches the speed range. A hydraulic control device for a vehicle automatic transmission comprising a clutch hydraulic servo that engages when the manual valve is shifted from a neutral position to a forward position. An accumulator is interposed in a first oil passage that communicates with the manual valve and the hydraulic servo, and a second oil passage that bypasses the first oil passage is provided in parallel, and a control valve is provided in the second oil passage. a solenoid valve interposed therebetween and disposed between the throttle valve and the control valve; and an electric control circuit for issuing a signal to the solenoid valve, the control valve having a spring behind it at one end and a first oil chamber into which a throttle pressure whose supply and discharge is controlled by a solenoid valve is introduced; a second oil chamber into which the throttle pressure supplied from the throttle valve is constantly introduced at the other end; and a third oil chamber connected to the oil passage,
When the solenoid valve is energized by a signal issued from the electric control circuit, the throttle pressure supplied to the first oil chamber is discharged, thereby causing the second oil passage to connect to the third oil chamber. It is characterized by being communicated through.

Furthermore, the present invention includes a hydraulic source, a regulator valve that regulates the hydraulic pressure from the hydraulic source to line pressure, a manual valve that manually switches between gear ranges, and a system that includes a hydraulic pressure source when the manual valve is shifted from a neutral position to a forward position. In a hydraulic control device for a vehicle automatic transmission comprising a hydraulic servo for a clutch to be engaged, a first valve communicating with the manual valve and the hydraulic servo;
and an accumulator for slowly applying hydraulic pressure supplied to the hydraulic servo to the first oil passage, forming a back pressure chamber for applying an accumulator back pressure on the back surface of the piston of the accumulator, and A solenoid valve for controlling the supply and discharge of back pressure of the accumulator is disposed between the back pressure chamber and the regulator valve, and an electric control circuit that issues a signal to the solenoid valve, and the electric control circuit generates a signal. When the solenoid valve is energized by the received signal, hydraulic pressure is supplied to the back pressure chamber of the accumulator, increasing the pressure on the back pressure side of the accumulator, and weakening the accumulating action of the accumulator, thereby supplying hydraulic pressure to the hydraulic servo. It is characterized by controlled speed.

[Operations and Effects] The hydraulic control device for a vehicle automatic transmission according to the present invention includes an accumulator in a first oil passage that communicates between the manual valve and the hydraulic servo when the manual valve is shifted from the neutral position to the forward position. A second oil passage is provided in parallel and bypasses the first oil passage, a control valve is interposed in the second oil passage, and the control valve inputs a throttle signal from the throttle valve; When the signal is equal to or higher than a predetermined value, the control valve is connected to the second control valve.
The manual valve and the hydraulic servo are communicated through an oil passage, and the control valve is shut off when the signal is below a predetermined value, so that the control valve is shut off during a normal ND shift and the accumulator is interposed. Since hydraulic pressure is supplied to the hydraulic servo from the first oil path, it is possible to relieve the shift shock during ND shift, and also, for example, when the ND shift is performed while the engine is normally revving, the control valve is in communication. By doing this, hydraulic pressure is supplied to the hydraulic servo from the second oil passage in addition to the first oil passage, so hydraulic pressure can be supplied faster than when hydraulic pressure is supplied to the hydraulic servo during a normal ND shift.
It is possible to prevent transient wear and burnout of the input clutch of the transmission that occurs during ND shifting under normal conditions such as idling, thereby ensuring its durability.

[Example] Next, the present invention will be described based on an example shown in the drawings.

FIG. 1 is a schematic diagram showing an example of a planetary gear unit of a known three-speed automatic transmission, and FIG. 2 is a circuit diagram of a hydraulic control device for a vehicle automatic transmission according to a first embodiment of the present invention. .

The planetary gear unit of the automatic transmission includes a torque converter 10 and a planetary gear transmission mechanism or transmission 30 with three forward speeds and one reverse speed, and is controlled by a hydraulic circuit device. The torque converter 10 includes a pump 55,
The pump 55 is connected to an engine crankshaft 58, and the turbine 56 is connected to a turbine shaft 59. Turbine shaft 59 is torque converter 10
This also serves as the input shaft 23 of a planetary gear transmission mechanism 30 with three forward speeds and one reverse speed. A multi-disc clutch 24 for transmission input is provided between the input shaft 23 and the intermediate shaft 29, and a multi-disc clutch 25 is provided between the input shaft and the sun gear shaft 80. A multi-disc brake 26, a multi-disc brake 40, and a one-way clutch 41 are provided between the sun gear shaft 80 and the transmission case 68. The sun gear 82 provided on the sun gear shaft 80 has a carrier 83,
A planetary pinion 84 supported by the carrier 83, a ring gear 85 meshing with the planetary pinion 84, another carrier 86, and a planetary pinion 8 supported by the carrier 86.
7. Together with the ring gear 88 that meshes with the planetary pinion 87, it constitutes a two-row planetary gear transmission. Ring gear 85 is connected to intermediate shaft 29. Further, the carrier 83 in this planetary gear device is connected to a ring gear 88 of the other planetary gear device, and these carrier 83 and ring gear 88 are connected to an output shaft 89. Further, a multi-disc brake 27 and a one-way clutch 28 are provided between the carrier 86 and the transmission case 68 in the other planetary gear set.

The planetary gear unit of an automatic transmission uses a hydraulic circuit to engage or release each clutch and brake according to the engine output and vehicle speed, and shifts to three forward gears or one reverse gear by manual switching. It's becoming like that.

Hydraulic control device 2 for a vehicle automatic transmission according to this embodiment
00 indicates that the hydraulic oil pumped up by the hydraulic pump 101 from the oil reservoir 100 of the hydraulic control device is regulated by the first regulator valve 102 and supplied to the oil path 1 at a predetermined oil pressure (line pressure) at the neutral position. At the time of a D (drive) shift which is a certain N (neutral) forward position, an engagement oil passage 201 supplies oil to a hydraulic servo 24B of an input clutch 24 of a transmission (gear transmission) via a manual valve 105; A flow control valve 202 with a check valve attached to the engagement oil passage 201 and an accumulator 2
03 and orifice 204, a direct oil passage 205 that supplies engagement hydraulic pressure (same level as the line pressure) without going through the flow control valve with check valve 202 and the accumulator 203, and a control valve 210 that opens and closes the direct oil passage 205. It is composed of.

The control valve 210 has a spring 211 placed behind it on the right side in the drawing, and has a spool 212 provided with two lands, from the right side in the drawing to the right end oil chamber 21.
3. An intermediate oil chamber 214 and a left end oil chamber 215 are formed. The control valve 210 has the engagement oil passage 201 always communicating with a right end oil chamber 213 provided with a spring 211, and a throttle valve 104 connected to the right end oil chamber 215 via a flow control valve 206 with a check valve.
When the spool 212 moves to the right in the figure, the direct oil passage 205 is opened via the intermediate oil chamber 214, and when the spool 212 moves to the left in the figure, the direct oil passage 205 is opened. 205 is blocked.

Next, the operation of the first embodiment will be explained.

Hydraulic oil that rises in accordance with the throttle opening is used as a detection means for detecting a state in which the transmission input is at a high rotational speed, and in this embodiment, throttle pressure is used. In this embodiment, when the throttle opening is small and the transmission input is at low rotation speed during ND shift, the throttle pressure introduced into the left end oil chamber 215 of the control valve 210 is low, so the force of the spring 211 is Spool 21
2 moves to the left in the figure, the direct oil passage 205 is in a closed state, and the manual valve 1 is closed during the ND shift.
Line pressure oil (engagement oil pressure) supplied from 05 to the hydraulic servo 24B of the input clutch is connected to the engagement oil path 20.
1, the engagement hydraulic pressure of the input clutch 24 acts slowly due to the action of the accumulator 203, and the shift shock is softened. Also N
During the D shift, when the throttle opening is large and the input to the transmission is high, the throttle pressure introduced into the left end oil chamber 215 of the control valve 210 is high, so the spool 212 moves to the right in the figure, and the The direct oil passage 205 is in an open state, and the line pressure oil (engagement oil pressure) supplied from the manual valve 105 to the hydraulic servo 24B of the input clutch at the time of ND shift is added to the engagement oil passage 201 as well as to the action of the accumulator 203. Since the direct oil passage 205 which is not exposed to the input clutch 20 also passes through, the engagement pressure oil of the input clutch 24 acts quickly, and wear and burnout of the input clutch 24 is prevented.

In the above embodiment, the hydraulic pressure of the control valve 210 is the throttle pressure, but as long as the hydraulic oil increases in accordance with the throttle opening, for example, regulator pressure may be used.

Next, a description will be given based on the embodiment shown in FIG.

FIG. 3 is a schematic diagram showing an example of a planetary gear unit of a known three-speed automatic transmission, and FIG. 4 is a circuit diagram of a hydraulic control device for a vehicle automatic transmission according to a second embodiment. Components equivalent to those in the first embodiment are designated by the same reference numerals.

Hydraulic control device 3 for a vehicle automatic transmission according to this embodiment
00 indicates a predetermined oil pressure (line pressure) at which the hydraulic oil pumped up by the oil pump 101 from the oil reservoir 100 of the hydraulic control device is regulated by the first regulator valve 102 and supplied to the oil path 1. When shifting from neutral to D (drive), the hydraulic servo 2 of the input clutch 24 of the transmission (gear transmission) is activated via the manual valve 105.
A direct oil passage 205 that supplies to 4B and the direct oil passage 2
A control valve 210A that opens and closes 05, and a solenoid valve 2 that controls the control valve 210A.
20 and its electric control circuit 207.

The control valve 210A has a spool 212A with a spring 211A placed behind it on the right side in the figure and a spool 212A provided with two lands.
13A, an intermediate oil chamber 214A, and a left end oil chamber 215A. The control valve 210A has an orifice 208 and an electric control circuit 20 described later in a right-end oil chamber 213A provided with a spring 211A.
Solenoid valve 220 whose opening and closing are controlled by 7
An oil passage 104A that supplies throttle pressure via the throttle valve 10 is connected to the left end oil chamber 215A.
When the solenoid valve 220 is energized (ON) in accordance with a command from the electric control circuit 207, the spool 212A moves to the right in the drawing, and the spool 212A moves to the right in the drawing, and the spool 212A moves to the right in the figure, and the spool 212A moves to the right in the figure. is opened, and when the solenoid valve 220 is de-energized (OFF), the spool 212A moves to the left in the figure, and the direct oil passage 205 is closed.

The electric control circuit 207 inputs signals from the throttle position sensor 207A, the shift position indicator sensor 207B, the throttle position sensor 207A, and the shift position indicator sensor 207B, and performs the ND shift within 0.7 seconds. The solenoid valve opening/closing determination circuit 207C energizes the solenoid valve 220 when the throttle opening is opened to a predetermined value or more.

Next, the operation of this second embodiment will be explained.

The hydraulic control device 300 for an automatic transmission for a vehicle according to the second embodiment is configured such that when performing an ND shift, the throttle opening is small and the input to the transmission is low rotation, or the throttle opening is changed within 0.7 seconds after the N shift. If the solenoid valve 220 is not opened beyond the set value, the solenoid valve 220 is opened by the action of the electric control circuit 207.
is de-energized, so the spool 212A of the control valve 210A moves to the left in the drawing, the direct oil passage 205 is closed, and oil is supplied from the manual valve 105 to the input clutch hydraulic servo 24B during the ND shift. The engagement oil pressure is the engagement oil path 20.
1, the engagement hydraulic pressure of the input clutch 24 acts slowly due to the action of the accumulator 203, and the shift shock is softened.

Also, when performing an ND shift, if the throttle opening is large and the transmission input is high rotation,
Or, if the throttle opening is opened beyond the set value within 0.7 seconds after the ND shift, the electric control circuit 2
07, the solenoid valve 220 is energized, and therefore the spool 2 of the control valve 210A is energized.
12A moves to the right in the figure and connects to the direct oil passage 205.
is in the open state, and the hydraulic servo 24B of the input clutch is operated from the manual valve 105 during the ND shift.
The line pressure (engaging oil pressure) supplied to is the engagement oil pressure 2.
01 as well as a direct oil passage 205 which is not affected by the action of the accumulator 203, so that wear and burnout of the input clutch 24 is prevented.

The hydraulic pressure of the control valve 210A used in this embodiment may be a regulator pressure, a line pressure, or the like.

Next, explanation will be given based on the embodiment shown in FIG.

FIG. 5 is a schematic diagram showing an example of a planetary gear unit of a known three-speed automatic transmission, and FIG. 6 is a circuit diagram of a hydraulic control device for a vehicle automatic transmission showing a third embodiment of the present invention. . Equivalents to the previous embodiments are designated by the same reference numerals.

Hydraulic control device 4 for a vehicle automatic transmission according to this embodiment
00 indicates a predetermined pressure oil (line pressure) at which the hydraulic oil pumped up by the oil pump 101 from the oil reservoir 100 of the hydraulic control device is regulated by the first regulator valve 102 and supplied to the oil path 1. (Neutral) When shifting to D (drive), the hydraulic servo 2 of the input clutch 24 of the transmission (gear transmission) is connected via the manual valve 105.
4B and the engagement oil passage 2
Flow control valve 202 with check valve attached to 01
and an accumulator 203, the line pressure is regulated by the second regulator valve 103 and the regulator pressure supplied to the oil passage 2 is controlled by the accumulator 2.
A solenoid valve 220 installed in the oil passage 3 communicating with the back pressure side 203B of 03, and the solenoid valve 22
0 electrical control circuit 230.

When the solenoid valve 220 is energized (ON) by the electric control circuit 230, it connects the oil passage 2 and the oil passage 3, introduces the regulator pressure into the back pressure side 203B of the accumulator 203, and controls the accumulator 2.
03 to make the movement of the input clutch 24 stiffer, the engagement hydraulic pressure of the input clutch 24 becomes faster, and the electric control circuit 203
When de-energized (OFF), oil passage 2 and oil passage 3
cut off contact with.

The electric control circuit 230 includes a throttle position sensor 231, a shift position indicator sensor 232, and a throttle position sensor 2.
31, shift position indicator sensor 23
The solenoid valve opening/closing determination circuit 233 inputs the signal from 2 and energizes the solenoid valve 220 when the throttle opening is opened by a predetermined value or more within 0.7 seconds after the ND shift.

Next, the operation of the third embodiment will be explained.

Hydraulic control device 4 for a vehicle automatic transmission according to this embodiment
00 indicates that the electric control circuit 230 is activated when the throttle opening is small and the transmission input is at low rotation speed during an ND shift, or when the throttle opening is not opened beyond the set value within 0.7 seconds after the ND shift. Solenoid valve 220 depending on the function
is de-energized, and therefore the supply of regulator pressure to the accumulator exhaust pressure side 203B is cut off, and the action of the accumulator 203 causes the input clutch 24 to
The engagement hydraulic pressure acts slowly, and the shift shock is relieved.

Also, when performing an ND shift, if the throttle opening is large and the transmission input is high rotation,
Or, if the throttle opening is opened beyond the set value within 0.7 seconds after the ND shift, the electric control circuit 2
30, the solenoid valve 220 is energized, so that the regulator pressure is increased to the accumulator 20.
3, the movement of the accumulator 203 becomes stiff, and the input clutch 24
This speeds up the action of the engagement hydraulic pressure and prevents wear and burnout of the input clutch.

FIG. 7 is a graph showing the relationship between the passage of time T from the ND shift and the change in the oil pressure Pc supplied to the hydraulic servo 24B of the input clutch 24.
Solid line A is when the accumulator 203 is working, two-dot chain line B is when the accumulator 203 is working hard, broken line C is the required engagement hydraulic pressure at low rotation input, and one-dot chain line D
indicate the required engagement hydraulic pressure at high rotation input. Further, T1 is the input time at high rotation by the hydraulic control device of the present invention, and T2 is the input time at high rotation when the conventional accumulator operates.

As described above, in the hydraulic control device for a vehicle automatic transmission according to the present invention, an accumulator is interposed in the first oil path that communicates the manual valve with the hydraulic servo when the manual valve is shifted from the neutral position to the forward position. In addition, a second oil passage bypassing the first oil passage is provided in parallel, and a control valve is interposed in the second oil passage, and the control valve receives a throttle signal from the throttle valve and receives the signal. When the signal is above a predetermined value, the control valve is communicated, and the manual valve and the hydraulic servo are communicated via the second oil path, and when the signal is below a predetermined value, the control valve is shut off. Therefore, during a normal ND shift, the control valve is shut off and the first
In order to supply hydraulic pressure from the oil passage to the hydraulic servo, N
This makes it possible to soften the shift shock during a D shift, and for example, in the case of an ND shift when the engine is revving, the control valve is communicated with the first
In addition to the second oil passage, hydraulic pressure is supplied to the hydraulic servo from the second oil passage, so hydraulic pressure can be supplied faster than when hydraulic pressure is supplied to the hydraulic servo during a normal ND shift. This makes it possible to prevent excessive wear and burnout of the input clutch of the transmission, which sometimes occurs, and to ensure its durability.

In addition, in each embodiment of the present invention, a means for preventing transient wear and burnout of the input clutch of the transmission that occurs during an ND shift has been described, but applying this to an NR shift is a design matter. be.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a planetary gear unit of a known three-speed automatic transmission, FIG. 2 is a circuit diagram of a hydraulic control device for a vehicle automatic transmission according to the present invention, and FIG. 3 is a schematic diagram of a planetary gear unit. figure,
FIG. 4 is a circuit diagram of a hydraulic control device for an automatic transmission for a vehicle showing a second embodiment of the present invention, FIG. 5 is a schematic diagram of a planetary gear unit, and FIG. FIG. 7 is a circuit diagram of a hydraulic control device for a vehicle automatic transmission shown in FIG. 7, and is a graph showing the relationship between engagement time and changes in engagement oil pressure. In the diagram, 1...oil passage, 2...oil passage, 3...oil passage,
24...Input clutch, 24B...Hydraulic servo, 100...Oil reservoir, 101...Oil pump, 102...First regulator valve, 103...
Second regulator valve, 104...throttle valve,
105...Manual valve, 200...Hydraulic control device for vehicle automatic transmission, 201...Engaging oil path, 2
02...Flow control valve with check valve, 203...Accumulator, 204...Orifice, 205...
... Direct oil passage, 206 ... Flow control valve with check valve, 210 ... Control valve, 210A ... Control valve, 220 ... Solenoid valve, 300
...Hydraulic control device for automatic transmission for vehicles, 400...
...Hydraulic control device for vehicle automatic transmission.

Claims (1)

[Scope of Claims] 1. A hydraulic source, a regulator valve that regulates the hydraulic pressure from the hydraulic source to line pressure, a throttle valve that generates a throttle pressure according to the throttle opening, and a manual that manually switches the speed range. valve and
A hydraulic control device for an automatic transmission for a vehicle, comprising a clutch hydraulic servo that engages when the manual valve is shifted from a neutral position to a forward position. An accumulator is interposed in a first oil passage that communicates with the manual valve and the hydraulic servo, and a second oil passage that bypasses the first oil passage is provided in parallel, and a control valve is provided in the second oil passage. The control valve receives a throttle signal from the throttle valve, and when the signal is equal to or higher than a predetermined value, communicates with the control valve to connect the manual valve and the hydraulic servo via the second oil path. A hydraulic control device for an automatic transmission for a vehicle, characterized in that the control valve is closed when the control valve is in communication and the signal is below a predetermined value. 2. A hydraulic source, a regulator valve that regulates the hydraulic pressure from the hydraulic source to line pressure, a throttle valve that generates a throttle pressure according to the throttle opening, and a manual valve that manually switches the speed range.
A hydraulic control device for an automatic transmission for a vehicle, comprising a clutch hydraulic servo that engages when the manual valve is shifted from a neutral position to a forward position. An accumulator is interposed in a first oil passage that communicates with the manual valve and the hydraulic servo, and a second oil passage that bypasses the first oil passage is provided in parallel, and a control valve is provided in the second oil passage. a solenoid valve interposed between the throttle valve and the control valve; and an electric control circuit for issuing a signal to the solenoid valve; a first oil chamber into which a throttle pressure whose supply and discharge is controlled by a solenoid valve is introduced; a second oil chamber into which the throttle pressure supplied from the throttle valve is constantly introduced at the other end; a third oil chamber connected to the oil passage, and when the solenoid valve is energized by a signal issued from the electric control circuit, the throttle pressure supplied to the first oil chamber is discharged. A hydraulic control device for an automatic transmission for a vehicle, wherein the second oil passage is communicated via the third oil chamber. 3. The electric control circuit inputs signals from the throttle position sensor, the shift position indicator sensor, and the throttle position sensor and the shift position indicator sensor, and shifts the manual valve from the neutral position to the forward position. and a solenoid valve opening determination circuit that energizes the solenoid valve when the throttle opening is opened to a predetermined value or more within 0.7 seconds after the throttle opening is opened to a predetermined value or more. Machine hydraulic control device. 4. A hydraulic source, a regulator valve that regulates the hydraulic pressure from the hydraulic source to line pressure, and a manual valve that manually switches gear ranges, which engages when the manual valve is shifted from a neutral position to a forward position. A hydraulic control device for a vehicle automatic transmission comprising a hydraulic servo for a clutch, comprising: a first oil passage connecting the manual valve and the hydraulic servo; and a hydraulic pressure supplied to the hydraulic servo in the first oil passage. an accumulator that acts slowly, a back pressure chamber that acts on the back pressure of the accumulator is formed on the back of the piston of the accumulator, and the back pressure of the accumulator is supplied and discharged between the back pressure chamber and the regulator valve. a solenoid valve that controls the solenoid valve, and an electric control circuit that issues a signal to the solenoid valve, and when the solenoid valve is energized by the signal issued from the electric control circuit, a back pressure chamber of the accumulator is supplied with electricity. A hydraulic control device for an automatic transmission for a vehicle, characterized in that the hydraulic pressure is supplied to strengthen the pressure on the back pressure side of the accumulator, and the accumulating action of the accumulator is weakened to control the supply speed of the hydraulic pressure supplied to the hydraulic servo. 5. The electric control circuit inputs signals from the throttle position sensor, the shift position indicator sensor, and the throttle position sensor and the shift position indicator sensor, and shifts the manual valve from the neutral position to the forward position. and a solenoid valve opening determination circuit that energizes the solenoid valve when the throttle opening is opened to a predetermined value or more within 0.7 seconds after the throttle opening is opened to a predetermined value or more. Machine hydraulic control device.