JPS60168943A - Creep prevention device for car provided with automatic speed changer - Google Patents

Abstract

PURPOSE:To prevent shift shock by arranging means for controlling the transmission capacity of frictional engaging element from zero to predetermined level in accordance to the fluid pressure between the frictional engaging element of automatic speed change element and hydraulic source and enabling quick transfer to creep preventing state when performing shift operation. CONSTITUTION:In a device where first speed gear series is established through coupling of first speed clutch C1 while second, third or fourth speed gear series is established through further coupling of second, third or fourth speed clutches C2-C4 under clutching of first speed clutch C1, a creep prevention valve 50 is placed in the way of pressure oil feed path 41 to the hydraulic operating section of first speed clutch C1. While a solenoid valve 70 having a valve body 71 for opening/closing the port 63a of seat 63 of said valve 50 is arranged at the seat 63 side end of creep prevention valve 50. Opening/closing of said solenoid valve 70 is controlled through drive circuit 102 in accordance with the outputs from brake detector 100 and engine rotation detector 101.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a creep prevention device for a vehicle equipped with an automatic transmission equipped with a fluid coupling such as a torque converter.

For vehicles equipped with an automatic transmission equipped with a fluid coupling such as a torque converter, if the gear shift lever is moved to the drive position (forward position) while the vehicle is stopped, the drag torque of the torque converter will cause the driver to Indicates a creep phenomenon in which the vehicle attempts to move forward against its will. This creep places a drag torque burden on the engine, which is undesirable from the viewpoint of improving fuel efficiency during idling. Therefore, during such idling, it is desirable to automatically set the transmission to a neutral state to cut off power transmission between the engine and the vehicle, and reduce the opening of the engine valve accordingly to ensure economy. It is also known that anti-creep devices made for this purpose also reduce vibrations during idling, especially for front-wheel drive vehicles (
The effect is remarkable in front-wheel drive (FF) cars.

Now, the creep prevention device smoothly resumes power transmission when starting, and when it is necessary to move the vehicle in a very narrow space, such as when riding in tandem, the creep prevention device automatically restarts the clutch in proportion to the slight amount of throttle pedal operation. It is desirable to be able to achieve a half-clutch state in which the clutch is engaged, but on the other hand, after the clutch has been engaged with the half-clutch engaged, such as when starting when there is no car in front, it is desirable to completely engage the clutch and do not apply any unnecessary force to the clutch. Preventing slippage is necessary from the viewpoint of clutch durability.

In addition, in vehicles equipped with a creep prevention device, if the throttle pedal is suddenly returned to the idle position immediately after the accelerator pedal is depressed, torque is applied to the entire engine and transmission, causing the mount rubber to After being strongly twisted, the twist is suddenly removed, causing the energy stored in the mount rubber to be released all at once, resulting in an unpleasant shock. To avoid this, it is effective to provide a delay function that allows the creep state to continue for a short time even after the slot pedal is released until the engine speed drops completely.

Therefore, the applicant first controlled the clutch engagement force in proportion to the stroke at the beginning of the stroke of the throttle pedal, and when the stroke exceeded a predetermined value, the clutch engagement force was reduced to its designed maximum value regardless of the stroke. Clutch prevention device for controlling
) and a creep prevention device has been proposed which has a delay function that continues the creep state for a short period of time until the engine speed drops to the idle speed even after the throttle pedal is released (Japanese Patent Application No. 145,808/1989). .

However, in the former case, since the feedback system of the creep prevention valve is configured to include a second control valve that opens and closes the feedback oil passage, it is necessary to connect the two valves when they are installed far apart. Two oil passages were required, which was a major design constraint. In addition, the latter delay function operates under any operating conditions of the system, for example, when the shift lever is moved from the neutral position (N range) to the forward position, such as the fourth gear position (D4 position).
There remains the inconvenience that it is not possible to eliminate the shift shock that occurs when shifting to range).

The present invention has been made in view of the above points, and it simplifies the oil passage and has a delay function, and furthermore, it quickly brings the shift lever into the creep prevention state without exerting the delay function. In order to achieve this purpose, the present invention uses a fluid coupling,
a transmission connected in series to the fluid coupling and having a forward frictional engagement element; a hydraulic source that supplies operating oil to the frictional engagement element; and an engine output detection means that outputs fluid pressure representative of the engine output. In a vehicle equipped with an automatic transmission, the frictional engagement element is interposed between the frictional engagement element and the hydraulic pressure source, and is connected to the engine output detection means via an oil passage, and the frictional engagement element is configured to adjust the frictional engagement element in response to the fluid pressure. a control means for controlling the transmission capacity of the coupling element from substantially 0 to a predetermined value; a branch oil passage branching from the oil pressure source and connected to the oil passage and including a restriction; and the branch oil passage of the oil passage. A creep prevention device for a vehicle equipped with an automatic transmission, comprising a switching valve connected between a connection point of the engine and the engine output detection means and closing the oil passage when the fluid pressure exceeds a set pressure. This is what we provide.

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an outline of an automatic transmission for an automobile with four forward speeds and one reverse speed to which the present invention is applied. In FIG. The signal is transmitted sequentially through the machine M and the differential device D to the drive vehicles w and w' to drive them.

The torque converter T includes a pump impeller 2a connected to a crankshaft 1, a turbine impeller 3 connected to an input shaft 5 of a transmission M, and a stator shaft 4a relatively rotatably supported on the input shaft 5, and a one-way clutch. The stator wheel 4 is connected via a stator wheel 7.

The torque transmitted from the crankshaft 1 to the pump wheel 2 is hydrodynamically transmitted to the turbine wheel 3, and when the torque is amplified during this time, the stator wheel 4 acts as a reaction force. bear the burden.

A pump drive gear 8 for driving the hydraulic pump P shown in FIG. 2 is provided at the right end of the pump impeller 2, and a stator shaft 4a
A stator arm 4b that controls the regulator valve Vr shown in FIG. 2 is fixed to the right end of the stator arm 4b.

Between the mutually parallel output shafts 5 and 6 of the transmission M, there is a first
Speed gear train G1, second speed gear train G2, third speed gear train G3,
Fourth speed gear trains G, 11 and reverse gear train Gr are provided in parallel. The first speed gear train G1 is a first speed clutch c
1, and a driven gear 18 that meshes with the gear 17 and is connectable to the output shaft 6 via a positional clutch Co. 2nd speed gear train G
2 consists of a driving gear 19 connectable to the input shaft 5 via a second speed clutch C2, and a driven gear 20 fixed to the output shaft 6 and meshing with the gear 19. The third speed gear train G3 includes a drive gear 21 fixed to the input shaft 5 and a third gear to the output shaft 6.
It consists of a driven gear 22 connected via a speed clutch C3 and capable of meshing with the gear 21 described above. Also, the fourth speed gear train G4 is
It consists of a driving gear 23 connected to the input shaft 5 via a fourth speed clutch C4, and a driven gear 24 connected to the output shaft 6 via a switching clutch Cs and meshing with the gear 23.

Furthermore, the reverse gear train Gr is the fourth speed gear train G,! It consists of a drive gear 25 that is integrally provided with the drive gear 23 of I, a driven gear 27 that is connected to the output shaft 6 via the switching clutch Cs, and an idle gear 26 that meshes with both gears 25 and 27. . The switching clutch Cs has a driven gear 24.2.
7, and by shifting the selector sleeve 8 of the clutch Cs to the forward position on the left or the 1 & advance position on the right in the figure, the tooth width 24.27 of the clutch Cs is transferred to the output shaft 6. Can be selectively linked. One-way clutch CQ transmits only driving torque from engine E, and does not transmit torque in the opposite direction.

Thus, when the selector sleeve S is held in the forward position as shown in the figure, if only the first speed clutch C1 is connected, the drive gear 17 is connected to the input shaft 5 and the first speed gear train G1 is activated. torque is transmitted from the input shaft 5 to the output shaft 6 via the gear train G1. Next, first gear clutch C
If the second speed clutch C2 is connected while the drive gear 19 is connected, the drive gear 19 is connected to the input shaft 5 and the second speed gear train G is connected.
2 is established, and torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train G2. At this time, the first gear clutch C
1 is also engaged, but due to the action of the one-way clutch CO, it is not in first speed but in second speed, and this is the same for third and fourth speeds. When the second speed clutch C2 is released and the third speed clutch C3 is connected, the driven gear 22 is connected to the output shaft 6 and the third speed gear train G3 is established, and when the third speed clutch C3 is released, the third speed gear train G3 is established. When the fourth speed clutch C4 is connected, the drive gear 23 is connected to the input shaft 5 and the fourth speed gear train G4 is established. Furthermore, by moving the selector sleeve S of the switching clutch Cs to the right and connecting only the fourth speed clutch C4, the driving gear 25 is connected to the input shaft 5, the driven gear 27 is connected to the output shaft 6, and the reverse gear train is connected. Gr is established, and reverse torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train Gr.

The torque transmitted to the output 6 is transmitted from the output gear 28 provided at the end of the shaft 6 to the large diameter gear Dg of the differential Df.

In FIG. 2, a hydraulic pump P sucks up hydraulic oil from an oil tank R and pumps it into a hydraulic oil passage 29. After this pressure oil is regulated to a predetermined pressure by a regulator valve Vr, it is sent to a manual valve Vm as a manual switching valve. This oil pressure is called line pressure Pβ.

Excess pressure oil in the regulator valve Vr is led into the torque converter T through an inlet oil passage 34 having a restriction 33, and pressurizes the inside thereof to prevent cavitation.

The hydraulic oil passage 29 is connected to a throttle valve Vt and a governor valve Vg as engine output detectors.

The throttle valve Vt is controlled according to the amount of depression of a slot pedal (not shown), and the throttle pressure pt is sent to the pilot oil passage 48 as an index corresponding to the throttle opening of the engine E, that is, an index representing the output of the engine E. Output. Further, the governor valve Vg is driven by the output shaft 6 of the transmission M or the large-diameter gear Dg of the differential device Df, and outputs oil pressure proportional to the vehicle speed, that is, governor pressure Pg, to the pilot oil path 49.

The manual valve Vm is an oil passage 39 branched from the hydraulic oil passage 29.
and /IIi path 40, and has shift positions such as a neutral position, a drive position, and a reverse position, and communicates with oil passages 39 and 40 when in the drive position. An oil passage 41 branching from the oil passage 40 is connected to a hydraulically actuated portion of the first speed clutch C1 via a creep prevention valve 50, which will be described later. The oil pressure in the oil passage 40 is supplied to the first clutch C1 via the creep prevention valve 50, and also to the 1-2 shift valve V+, the 2-3 shift valve V2, the 3-4 shift valve ■3
According to the switching operation, the hydraulic pressure is switched and supplied to each of the hydraulic operating parts of the second speed clutch C2, third speed clutch C3, and fourth speed clutch C4.

Throttle pressure Pt and governor valve Pg are applied to both ends of these shift valves ■1 to ■3, and they shift from the first switching position on the left side to the right side in response to an increase in vehicle speed, that is, an increase in governor pressure Pg. Switching operation is performed to the second J switching position. In other words, 1-2 shift 1 to valve ■1 are oil passage 40 and throttle 43
The oil passages 40 and 42 are interposed between the oil passages 40 and 42, and when the vehicle speed is low, the oil passages 40 and 42 are in a first switching position where the oil passages 40 and 42 are cut off. Therefore, in this state, only the first clutch C1 is engaged, and the speed ratio of the first speed is established.

Vehicle speed? - When it increases, the 1-2 shift valve ■1 is right +! ul
is switched to the second switching position, and the oil passages 40 and 42 are communicated. At this time, the 2-3 shift valve 12 is in the first switching position shown, and the oil passage 42 is communicated with an oil passage 44 leading to the hydraulically operating portion of the second speed clutch C2. Therefore, the first speed clutch C1 and the second speed clutch C2 are engaged, but due to the action of the one-way clutch Co (see Figure 1), only the second speed gear train G2 is established, and the second speed It becomes a ratio.

When the vehicle speed further increases, the 2-3 shift valve V2 switches to the second switching position on the right side, and the oil passage 42 switches to the oil passage 45.
will be communicated to. At this time, the 3-4 shift valve V3 is in the first switching position on the left side as shown in the figure, and the oil passage 45 is communicated with an oil passage 46 leading to the hydraulically operating portion of the third speed clutch C3. Therefore, the third gear clutch C3 is engaged and the third gear speed ratio is established.

When the vehicle speed further increases, the 3-4 shift valve V3 is switched to the second right-hand switching position, and the oil passage 45 is communicated with the oil passage 47 leading to the hydraulically actuated portion of the fourth speed clutch C4. Therefore, the fourth gear clutch C4 is engaged and the fourth gear speed ratio is established. Automatic transmissions having such a configuration are known.

Now, the hydraulic pressure (line pressure Pβ) from the hydraulic pump P is applied to the hydraulic operating part of the first speed clutch C1, which is a frictional engagement element for starting.
A boat 51 of a creep prevention valve 50, which is interposed in the middle of the oil passage 41 for supplying the oil, is connected to the oil passage 40 with respect to the oil passage 41, and a boat 52 is connected to the hydraulic operating part of the first speed clutch C1. . One end surface 5.5a of the spool 55 is connected to the other end surface 5.5a.
It has a larger diameter than b and its pressure receiving area is set larger,
Holes 56 and 57 are concentrically formed in the axis of the end face 55a, holes 58 are formed in the axis of the end face 55b, and the boats 51 and 52 are formed in the outer peripheral surface in the first switching position shown. A communicating annular groove 59 is provided, and the annular a59 and the holes 57 and 58 communicate with each other through small holes (hereinafter referred to as apertures) 60 and 61. A one-way valve 62 is disposed in the hole 57 to allow pressure oil to flow only from the hole 57 toward the hole 56 side.

A spring 64 is fitted into the hole 56 of the spool 55, and one end of the spring 64 is pressed against the end surface of the spring 56 and the other end is pressed against the opposite end surface of the sheet 63.
A pressure chamber 65 is defined between the sheet 63 and the opposite end surface, and a hole (hereinafter referred to as a boat) 63a is bored in the axis of the sheet 63. The spring pressure of the spring 64 is set to a value approximately equal to or slightly lower than the spring pressure of a return spring (not shown) included in the first clutch C1. In addition, the boats 51 and 52 have a creep prevention valve 5.
A one-way valve 68 is disposed in the oil passage 67 to allow hydraulic pressure to flow only from the boat 52 to the 51 side.

The solenoid valve 70 is fixed to the end of the creep prevention valve 50 on the seat 63 side, and the valve body 71 closes (closes) the boat 63a of the seat 63 by the spring force of a spring 72 when deenergized, and closes the boat 63a of the seat 63 when it is energized. The boat 63a is opened (opened) by suctioning the valve body 71 against the spring force. Valve body 7 of this solenoid valve 70
1 is a poppet valve that closes the poppet valve 63a by a spring 72, and its closing pressure is set so as to maintain the pressure in the pressure chamber 65 at a predetermined pressure ΔP when deenergized. That is, the solenoid valve 70 sets the spring pressure of the spring 72 weakly, and when the pressure in the pressure chamber 65 exceeds a predetermined pressure P, it closes according to the excess pressure. During times of crisis, it is communicated with the boat 53 via the boat 63a. Further, the pressure chamber 64 is communicated with the boat 53 via an oil passage 54,
A one-way valve 66 is arranged in this oil passage 54 to allow hydraulic pressure to flow only from the boat 53 toward the pressure chamber 65 side. This oil passage 67 and one-way valve 68 are manual valve V
In order to quickly release the engagement by returning the oil pressure in the first speed clutch C1 to the low pressure side when shifting the clutch C1 from the forward position to the intermediate position or the reverse position, thereby rapidly reducing the internal pressure of the clutch C1. This is especially effective when the viscosity of the hydraulic fluid is low in cold weather.

The oil passage 90 branched from the pilot oil passage 48 is a manitsu oil passage.

connected to the boat 75a of the switching valve 75 through a 2-bow 1-2 position switching valve 74 that is provided in the manual valve Vm and opens at the forward shift lever position of the manual valve Vm,
The bow) 75b of the switching valve 75 is connected to the port 53 of the creep prevention valve 50 via an oil passage 91, and the oil passage 92, which is branched from the pilot oil passage 48 and communicates with the oil passage 91, is connected to the oil passage 92 from the pilot oil passage 48 to the oil passage 91. A one-way valve 82 is disposed that allows hydraulic pressure to flow only toward the side. Switching valve 75
The left end pressure chamber 78 is connected to the oil passage 90 via a one-way valve 79 that allows hydraulic pressure to flow only toward the pressure chamber 78 side, and is also connected to the oil passage 92 through a throttle 80. be done.

The surface of the spool 76 of the switching valve 75 is provided with an annular groove 76a that communicates between ports 75a and 75b in the first switching position shown, and the spool 76 is moved to the first switching position shown in the drawing by the spring pressure of a spring 77. Switched. Then, when the pressure in the pressure chamber 78 exceeds the reference pressure Ps set by the spring 77, the spool 76 is pushed to the right in the figure and switched to the second switching position, and the connection between the bows 75a and 75b is cut off. , the valve is closed and oil passages 90 and 91 are cut off.

The switching valve 75 has the throttle pressure Pt of the oil passage 90 set to the reference pressure Ps.
The valve closes when the temperature exceeds the limit, and opens when the following conditions occur.

And it has a delay function when opening the valve from the closed state,
This delay function is accomplished by a one-way valve 79 and a throttle 80. That is, when the throttle pressure Pt increases, the one-way valve 7
9 and the throttle 80, the throttle pressure pt is the switching valve 75.
As a result, the switching valve 75 closes without delay to cut off the oil passages 90 and 91. On the other hand, when the throttle pressure Pt decreases, the oil pressure in the pressure chamber 78 is reduced by the throttle 8.
Since it flows out only through 0, the amount of outflow is small, and as a result, even after the throat/nottle pressure P (has finished decreasing), the open/close valve state is maintained for a while, and a delayed operation is performed. The valve 79 and the throttle 80 constitute a single-effect throttle,
The one-way throttle, that is, the one-way valve 79, the throttle 80, and the switching valve 7
5 constitute a delay valve 81, and these one-way valves 79
And the throttle 80 is formed integrally with the switching valve 75.

The brake detector 100 detects whether or not a brake pedal (not shown) is depressed, and outputs a high-level signal when the brake pedal is depressed. This brake detector 100 uses, for example, a strobe lamp switch.

The engine rotation speed detector 101 detects the engine rotation speed Ne by, for example, measuring the interval of engine ignition pulse signals, and the detected engine rotation speed N
When e is less than a predetermined rotation speed Ns which is slightly higher than the reference rotation speed, for example, the idle rotation speed, a high level signal is output.

The brake detector 100 and the engine speed detector 101 are connected to respective input terminals of the ant circuit 103 of the drive circuit 102, and the AND circuit! The output terminal of 03 is connected to the base of transistor 1r. This transistor Tr
The emitter of the solenoid is grounded, the collector is connected to one end of a solenoid (not shown) of the solenoid valve 70 via an IJj 1104, and the other end of the solenoid is connected to a predetermined power source (not shown) via a line 105. be done.

The operations of the creep prevention valve 50 and the delay valve 81 will be explained below.

When the vehicle is running, the outputs of the brake detector 100 and the engine speed detector 101 are each at a low level, the transistor Tr is rendered non-conductive (hereinafter referred to as OFF), and the solenoid valve 70 is deenergized. On the other hand, an accelerator pedal (not shown) is depressed, and oil pressure pt corresponding to the amount of depression of the accelerator pedal is supplied to the oil passage 90.92.
When the oil pressure Pt exceeds the reference pressure Ps, the delay valve 81
The spool 76 is pushed to the right in the figure to close the delay valve 81.
The valve is closed, and the oil passage 91 is cut off from the oil passage 90. Therefore, at this time, the pressure oil in the pressure chamber 65 of the creep prevention valve 50 has no place to escape. Line pressure P of oil passage 41
A part of Il is the throttle 60 of the spool 55 of the creep valve 50.
．． 61 to both end surfaces 55a and 55b,
The spool 55 is lowered to the first switching position as shown in the figure due to the difference in the pressure receiving areas and the spring pressure of the spring 64,
An annular a59 connects the boats 51 and 52. As a result, the line pressure Pβ is supplied to the hydraulically actuated portion of the first speed clutch C1, and the clutch C1 is reliably engaged.

Suppose now that in order to stop the vehicle, the accelerator pedal is released and the brake pedal is depressed. As the accelerator pedal is released, the throttle pressure Pt decreases. However, the delay valve 81 is maintained in the open/closed valve state for a while due to its delay function. This delay function prevents shock even if you suddenly release the accelerator pedal. Then, when the engine rotation speed Ne becomes lower than the reference rotation speed N514, the output signal of the engine rotation speed detector 101 becomes high level. On the other hand, the brake detector 100 has already outputted a high level signal when the brake pedal is depressed, so the output of the AND circuit 103 becomes high level and the transistor 1r becomes conductive (hereinafter referred to as on).
Then, the solenoid valve 70 is energized and the boat 63a is opened.

At this time, the delay valve 82 has already been switched to the first position and opened as shown in the figure, and the passage 91 is connected to the oil passage 9.
0 connected. Therefore, the pressure oil in the pressure chamber 65 of the creep prevention valve 50 escapes to the low pressure side via the oil passages 91 and 90, and the pressure in the pressure chamber 65 decreases. As a result, the spool 55 is pushed upward in the figure by the hydraulic pressure acting on its end surface 55b, the boats 51 and 52 are cut off, and the oil passage 41
That is, the first speed clutch C1 is disconnected from the hydraulic power source. At this time, the force pushing up the spool 55, that is, the clutch pressure of the first speed clutch C1, is controlled to the set pressure PO determined by the spring pressure of the spring 64. As mentioned above, this set pressure PO is set to a value Pe (engagement pressure) that approximately corresponds to the strength of the return spring inherent in the first gear clutch C1, or a value slightly lower than this. C1 becomes completely disconnected.

As a result, creep is prevented when the vehicle is stopped.

Next, when the brake pedal is released in order to start the vehicle, the output signal of the brake switch 100 becomes low level, and as a result, the AND circuit! The output of 03 becomes low level, transistor Tr turns off,
The solenoid valve 70 is deenergized, and the valve body 71 acts to close the valve 63a under the pressure of the spring 72. If the accelerator pedal is not depressed at this time, the pressure chamber 6
The pressure oil in the pressure chamber 65 escapes to the low pressure side via the oil passage 91, the delay valve 81, and the oil passage 90, and the pressure oil in the pressure chamber 65 is controlled to the predetermined pressure ΔP described above. As a result, the creep prevention valve 50 becomes the same as if the spring pressure of the T-degree spring 64 had become stronger by an amount corresponding to the predetermined pressure ΔP, and the internal pressure of the hydraulic actuating part of the first speed clutch C1 has changed from the set pressure PO to (Po+ΔP). P)
It will be raised to This increase in pressure ΔP completely eliminates the ineffective stroke of the hydraulically actuated portion of the first speed clutch C1. This pressure ΔP may be a small pressure. By removing the invalid stroke in this way, the creep state can be reliably achieved, and since the pressure change from the set pressure PO is only a small amount of △P, when the brake pedal is released, The clutch pressure P of the first speed clutch C1 at this time, when the shock is suppressed to a minimum, is indicated by the chain line ■ in FIG. In the figure, pressure Pe indicates the engagement pressure at which the return spring of the piston of the hydraulic actuating part of the first speed clutch C1 is equalized with the internal pressure. If the internal pressure is higher than this pressure Pe, creep occurs, and if it is lower, Does not cause creep.

Next, when the accelerator pedal is depressed, the oil pressure Pt corresponding to the amount of depression is applied to the oil path 90. Pressure chamber 6 of creep prevention valve 5° via delay valve 8I, oil passage 91 and one-way valve 66
5, the spool 55 is pressed downward in the figure, and the first speed clutch C1 is connected to the oil passage 41. When the throttle pressure Pt is lower than the reference pressure Ps, the delay valve 81 is opened, and the spool 55 moves downward as the throttle pressure Pt increases, and the boat 52 is gradually communicated with the boat 51 accordingly. As a result, the clutch pressure P of the first speed clutch C1 changes as shown by the solid line 3 in FIG. This creep prevention valve 50 is basically switched to the creep recovery position by the throttle pressure pt.

When the throttle valve opening reaches the predetermined opening θ0 and the throttle pressure Pt exceeds the reference pressure Ps, the delay valve 81 closes and the oil passage 90 is blocked, and as a result, the creep prevention valve 5
The pressure applied to both end surfaces 55a and 55b of the 0 spool 55 becomes equal, and the spool 55 moves downward to the first switching position shown in the figure due to the difference in pressure receiving area and the spring pressure of the spring 64, and the boat 52 is moved to the boat 51. completely connected. As a result, the line pressure Pe of the oil passage 41 is supplied to the hydraulic actuating part of the first speed cronona c1, and the clutch pressure P becomes the line pressure P1 shown by the solid line ■ in Fig. 3, increasing its transmission capacity to the maximum value. , the first link clutch 01 is reliably engaged.

In addition, when the accelerator pedal is depressed while the brake pedal is depressed, the solenoid valve 7o is in an open state, and the clutch pressure P is the pressure Po shown by the solid line ■ in Fig. 3. Accordingly, hydraulic pressure Pt is supplied from the oil passage 91 through the boat 63a and the one-way valve 66 into the pressure chamber 65, and accordingly, the pressure P is increased to the third level.
It changes as shown by the solid line ■ in the figure.

Further, since the delay valve 8I performs a delay action only when the valve is opened, the throttle pressure pt is normally 0 when shifting from the neutral (N) range to, for example, the fourth (D4) range, but the delay valve 81 is open, and therefore, to prevent creep, the valve 50 immediately shuts off the oil [2841] between the first gear clutch C1 and the hydraulic power source to prevent engagement of the clutch C1, and as a result, the shift The shock is removed.

Note that if the switching valve 74 interposed in the oil passage 90 is configured to open only in the fourth gear (D4) range of the shift lever and close in other ranges, the switching valve 74 in the fourth gear (D'4 range) It is possible to create a system that only prevents the creep.

As explained above, according to the present invention, a fluid coupling, a transmission connected in series to the fluid coupling and having a forward frictional engagement element, a hydraulic source that supplies hydraulic oil to the frictional engagement element, In a vehicle equipped with an automatic transmission equipped with an engine output detection means that outputs a fluid pressure representative of the engine output, the engine output is interposed between the frictional engagement element and the hydraulic pressure source and is transmitted through an oil path. control means connected to the detection means and controlling the transmission capacity of the friction engagement element from substantially 0 to a predetermined value according to the fluid pressure; and a throttle branched from the hydraulic transmission and connected to the oil passage. a branch oil passage; and a switching valve that is connected between a connection point of the oil passage with the branch oil passage and the engine output detection means and closes the oil passage when the fluid pressure exceeds a set pressure. With this, there is no need to provide an extra oil passage, and the degree of freedom in design can be greatly increased, reducing costs and improving ease of assembly.

Further, the switching valve is provided with a single-effect throttle that causes a delay in following changes in the fluid pressure when the valve is open compared to when the valve is closed, so that it has a delay function, and a delay function is provided for shifting of the shift lever. The delay function is activated only when the accelerator pedal is operated, so even if the accelerator pedal is suddenly released, the delay function will not be triggered due to fluctuations in engine speed. In addition, it is possible to eliminate shift shock when the shift lever is range shifted from the neutral position to the forward position.

[Brief explanation of the drawing]

FIG. 1 is a skeleton diagram of a power transmission system of a vehicle equipped with a four-speed forward automatic transmission to which the present invention is applied, and FIG. 2 is a control of the automatic transmission of FIG. 1 to which the creep prevention device according to the present invention is applied. FIG. 3 is a diagram showing an embodiment of the circuit, and is a characteristic diagram showing the operation of the creep prevention device of the control circuit shown in FIG. 2. E: Engine, T: Torque converter, M: Transmission, D: Hydraulic pump, Vm: Manual valve,
01-C4... 1st - 4th speed clutch, 50... Creep prevention valve, 70... Solenoid valve, 81... Delay valve,
100... Brake detector, 101... Engine rotation speed detector. Applicant Honda Motor Co., Ltd. Agent Toshihiko Watanabe Kanji Nagato

Claims (1)

[Claims] 1. A fluid coupling, a transmission connected in series to the fluid coupling and having a forward frictional engagement element, a hydraulic source that supplies hydraulic oil to the frictional engagement element, and a hydraulic source that supplies hydraulic oil to the frictional engagement element; In a vehicle equipped with an automatic transmission including an engine output detection means that outputs a representative fluid pressure, the engine output detection means is interposed between the friction sensing engagement element and the hydraulic pressure source and is connected to the engine output detection means via an oil passage. a control means connected to the means for substantially controlling the transmission capacity of the frictional engagement element from 0 to a predetermined value according to the fluid pressure; and a throttle branched from the hydraulic pressure source and connected to the oil passage. A switch that intervenes between a branch oil passage, a connection point of the oil passage with the branch oil passage, and the engine output detection means to block the oil passage when the fluid pressure exceeds a set pressure. A creep prevention device for a vehicle equipped with an automatic transmission, characterized by comprising a valve. 2. The switching valve according to claim 1, wherein the switching valve is provided with a single-effect throttle that causes a delay in following changes in the fluid pressure when the valve is open compared to when the valve is closed. Anti-creep device for vehicles with automatic transmissions.