JPH0474583B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a creep prevention device for a vehicle with an automatic transmission.

If a vehicle equipped with an automatic transmission is set to the drive position (forward position) while the vehicle is stopped, the drag torque of the torque converter will cause
This indicates a so-called creep phenomenon in which the vehicle tries to move forward against the driver's will. This creep force attempts to apply a braking force to the engine during idling, so in order to keep the engine speed at the reference value during idling, the throttle opening during idling must be adjusted to compensate for this braking force. This naturally increases fuel consumption, which is one of the main reasons for the poor fuel efficiency of vehicles with automatic transmissions.

Therefore, the applicant detects the idling state of the vehicle and diverts the pressure of the starting clutch to the oil tank to cut off the power transmission between the engine and the wheels, reducing the load on the engine to the same level as that of vehicles with manual transmissions. We are first proposing improvements that would make this possible. However, in this improvement proposal, when designing an automatic transmission in which the gear position during idling operation, for example, the low gear position, is also used during engine braking, it is necessary to
A means for distinguishing between engine braking and engine braking is required, such as detecting vehicle speed or engine rotational speed, which makes the system complex and expensive. Furthermore, the reliability of these detection means is not absolute, so when these detection means fail, the engine brake becomes ineffective and the vehicle must rely on the foot brake.

The present invention was made to eliminate such drawbacks, and focuses on the fact that engine braking is always activated by the driver moving the shift lever, and the oil path is switched using a manual valve linked to the shift lever. The object of the present invention is to provide a creep prevention device having a simple structure and capable of reliably operating an engine brake.

According to the present invention, in order to achieve such an objective,
a hydraulic torque converter; an auxiliary transmission having frictional engagement elements for starting and engine braking and connected to the torque converter; and a hydraulic oil path for supplying hydraulic oil from a hydraulic source to the frictional engagement elements. a creep prevention valve that is installed in an oil passage branching from the hydraulic oil passage and leading to the oil tank and opens the oil passage when the vehicle is idling; and a manual valve that can open and close the hydraulic oil passage in conjunction with the gear shift lever. and
In the creep prevention device for a vehicle with an automatic transmission, the manual valve has at least a drive position and a first gear holding position set as shift positions, wherein the manual valve is set in the friction engagement position when the manual valve is in the drive position. The hydraulic oil passage that establishes communication between the frictional engagement element and the hydraulic source is communicated with the creep prevention valve, but when the hydraulic oil passage is in the first gear holding position, the hydraulic oil passage communicates between the frictional engagement element and the hydraulic source. so that the frictional engagement element is isolated from the creep prevention valve while maintaining the communication state;
Provided with oil passage switching function.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.First, in FIG. The signal is sequentially transmitted to the drive wheels W, W' through the converter T, the auxiliary transmission M, and the differential device Df, and drives them.

The torque converter T includes a pump impeller 2 connected to a crankshaft 1, a turbine impeller 3 connected to an input shaft 5 of an auxiliary transmission M, and a stator shaft 4a supported on the input shaft 5 so as to be relatively rotatable. It is composed of a stator wheel 4 connected via a one-way clutch 7. The torque transmitted from the crankshaft 1 to the pump impeller 2 is hydrodynamically transmitted to the turbine impeller 3, and during this time, when the torque is amplified,
As is known, the stator wheel 4 bears the reaction force.

A pump drive gear 8 for driving the hydraulic pump P shown in FIG. 22 is provided at the right end of the pump impeller 2, and a stator arm 4b for controlling the regulator valve Vr shown in FIG. 2 is fixed at the right end of the stator shaft 4a. will be established.

The input and output shafts 5 of the auxiliary transmission M are parallel to each other.
A low-speed gear train G ₁ , a medium-speed gear train G ₂ , a high-speed gear train G ₃ , and a reverse gear train Gr are provided in parallel between the gears 6 and 6. The low-speed gear train G ₁ includes a drive gear 1 connected to the input shaft 5 via a low-speed clutch C ₁ that serves as a frictional engagement element for starting and engine braking.
7 and a driven gear 18 which is fixedly attached to the output shaft 6 and meshes with the gear 17, and the middle speed gear train _G2 is connected to the input shaft 5 via the middle speed clutch _C2 . The high-speed gear train G ₃ is composed of a driving gear 19 and a driven gear 20 that is connected to the output shaft 6 via a switching clutch Cs and meshes with the gear 19. and,
It consists of a driven gear 22 connected to the output shaft 6 via a high speed clutch _C3 , and a reverse gear train.
Gr is a driving gear 23 formed integrally with the driving gear 19 of the middle speed gear train _G2 , and a driven gear 24 connected to the output shaft 6 via the switching clutch Cs.
Idle gear 2 meshing with both gears 23 and 24
It consists of 5 and more. The switching clutch Cs is provided between the driven gears 20, 24, and outputs the driven gears 20, 24 by shifting the selector sleeve 26 of the clutch Cs to a forward position on the left or a reverse position on the right in the figure. It can be selectively connected to the shaft 6.

Thus, when the selector sleeve 26 is held in the forward position as shown, the low gear clutch is
If only C ₁ is connected, the drive gear 17 will be connected to the input shaft 5.
A low speed gear train G ₁ is established, and torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train G ₁ . Next, if the low gear clutch C ₁ is disconnected and the middle gear clutch C ₂ is connected,
A medium speed gear train G ₂ is established in which the drive gear 19 is connected to the input shaft 5 , and the input shaft 5 is connected to the input shaft 5 via this gear train G ₂ .
Torque is transmitted from the output shaft 6 to the output shaft 6. Furthermore, if the low speed gear clutch C ₁ and the middle speed gear clutch C ₂ are disconnected and the high speed gear clutch C ₃ is connected, the driven gear 22 is connected to the output shaft 6 and the high speed gear train is connected.
_G3 is established, and torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train _G3 . Next, by switching the selector sleeve 26 to the right reverse position and connecting only the middle gear clutch _C2 , the drive gear 23
is connected to the input shaft 5, and the driven gear 24 is connected to the output shaft 6 to establish a reverse gear train Gr, and torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train Gr.

The torque transmitted to the output shaft 6 is transmitted from the output gear 27 provided at the end of the shaft 6 to the large diameter gear 28 of the differential device Df.

In FIG. 2, a hydraulic pump P sucks up 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. This oil pressure is called line pressure Pl.

The regulator valve Vr has a pressure regulating spring 30 and a spring receiver 31 that supports the outer end of the spring receiver 33. The spring receiver 331 can be moved left and right to adjust the set load of the pressure regulating spring 30. . The stator arm 4b is in contact with the outer surface of the spring receiver 31 so as to apply a reaction force acting on the stator wheel 4, that is, a stator reaction force. A stator spring 32 supporting the is connected. Therefore, if the stator reaction force increases, the stator spring 32 will be compressed.
Along with this, the spring receiver 31 moves to the left and the pressure regulating spring 30
As a result, the hydraulic oil passage 29
The line pressure Pl of is increased.

A part of the pressure oil whose pressure is regulated by the regulator valve Vr is guided into the torque converter T through an inlet oil passage 34 having a throttle 33, and pressurizes the inside of the torque converter T to prevent cavitation, but this internal pressure is The size of the throttle 33, the strength of the spring 37 of the check valve 36 provided in the outlet oil passage 35 of the torque converter T, etc. are determined.

The oil that has passed through the check valve 36 is sent to the oil cooler 5.
6 and return to oil tank R.

The surplus of pressure oil discharged from the hydraulic pump P is guided to the lubricating oil path 38 from the regulator valve Vr and sent to each lubricating part, but in order to ensure the minimum necessary oil pressure at this time, the pressure regulating valve 39 is installed. It is connected to the lubricating oil path 38.

The pressure oil sent to the manual valve Vm is
is in the neutral position N shown, the clutch
It is not sent to any of C ₁ , C ₂ , C ₃ and other various hydraulic operating parts. Therefore, all three clutches C ₁ , C ₂ , C ₃ are disengaged, and the torque of the engine E is not transmitted to the wheels W, W'.

When the manual valve Vm moves one step to the left from the illustrated position and is shifted to the drive position D, the hydraulic oil passage 29 from the hydraulic pump P communicates with the oil passages 43 and 118, and is provided with a one-way throttle 75. Oil road 111
is connected to a hydraulic oil passage 41a leading to a hydraulic cylinder 40a of the low gear clutch _C1 . In addition, oil path 11
2 is cut off from the hydraulic oil passage 41b leading to the hydraulic cylinder 40b of the middle gear clutch C ₂ , and the oil passage 113a
is also blocked from the exhaust port 114. Oil road 115
continues to communicate with exhaust port 116. The hydraulic oil passage 43 communicates with the spring chamber 42 of the hydraulic servo motor Sm for shifting the selector sleeve 26, so that the piston 44 of the servo motor Sm remains in the leftward movement position shown in the figure and is moved through the shift fork 45. to hold the selector sleeve 26 in the forward position shown in FIG. Therefore,
The reverse gear train Gr is placed inactive.

An input oil passage 46 that connects to the input port of the governor valve Vg branches from the hydraulic oil passage 29, and a first signal oil passage 47 extends from the output port of the valve Vg.

The governor valve Vg is a known one, and is rotated around its own rotation axis 49 by a gear 48 meshing with the large-diameter gear 28 of the differential device Df. Therefore, since its rotational speed is proportional to the vehicle speed, the governor valve Vg transmits the hydraulic pressure proportional to the vehicle speed, that is, the governor pressure Pg, to the first signal oil path by the action of the centrifugal force acting on the weight 51 of the spool valve body 50. 47.

Further, an oil passage 53 branches from the hydraulic oil passage 43, and this oil passage 53 is connected to the first throttle valve Vt ₁ via a modulator valve 54. The modulator valve 54 is a pressure reducing valve that is biased toward the closing side by a spring force and closed by the modulator pressure of the output port 54a, and defines the upper limit value of the inlet pressure of the first throttle valve _Vt1 .

The first throttle valve Vt ₁ is of a known type, and includes a spool valve body 55, a control spring 58 that presses the valve body 55 to the left, and a return spring 5 that presses the valve body 55 to the right.
7. Control piston 59 that supports the outer end of control spring 58, control cam 60 that rotates in conjunction with the increase in opening of the throttle valve of engine E and moves control piston 59 to the left, and adjusts the set load of return spring 57. It has an adjustment bolt 61 etc. that can be adjusted. When the control piston 59 moves to the left, the displacement is transmitted to the spool valve body 55 via the control spring 58 and pushes it to the left. Since the left shoulder portion 55a of the spool valve body 55 acts to push the body 55 back to the right, the first
The throttle valve Vt ₁ outputs a hydraulic pressure proportional to the opening degree of the throttle valve of the engine E, that is, a throttle pressure Pt, to the second signal oil path 52 . In addition, the control cam 60
The rotation in the counterclockwise direction continuously restricts the communication between the oil passage 117 and the oil tank R.

The first and second signal oil passages 47, 52 are pilot hydraulic chambers 62a, 62b: 63a: 63 at both ends of the low-medium speed shift valve _V1 and the medium-high speed shift valve _V2, respectively.
b, respectively. As a result, each of the spool valve bodies 64 and 65 of these shift valves V ₁ and V ₂ receives the governor pressure Pg and throttle pressure Pt on both end faces and is operated as follows.

That is, the spool valve body 6 of the low-medium speed shift valve _V1
4 is initially held at the rightward movement position shown in the figure by the force of the spring 66, and therefore the oil passage 118 is communicated with the hydraulic oil passage 41a via the oil passage 111, and the low gear clutch is connected to the hydraulic oil passage 41a.
C ₁ is engaged under pressure. Next, the vehicle speed increases and the governor pressure Pg increases, and when the left power of the spool valve element 64 due to this governor pressure Pg overcomes the right power of the valve element 64 due to the first throttle pressure Pt ₁ and the spring 66, the valve In a click motion mechanism 67 provided at the right end of the body 64, a click ball 68 moving together with the valve body 64 rides over a fixed positioning protrusion 69, and the valve body 64 is rapidly switched to the left movement position. As a result, the oil passage 111 becomes the drain oil passage 119.
The oil passage 118 communicates with the oil passage 70 . Further, the oil passage 70 is blocked from the drain oil passage 120.
In this state, if the medium-high speed shift valve _V2 is in the position shown, the oil passage 70 communicates with the oil passage 113 provided with the one-way throttle 121, and further communicates the manual valve Vm with the hydraulic oil passage 41b. . Therefore, hydraulic oil is supplied to the hydraulic cylinder 40b, and the middle gear clutch _C2 is engaged under pressure. As a result, the middle speed gear train _G2 is established.

As the vehicle speed increases further, the medium-high speed shift valve
A similar effect occurs in valve V ₂ , and the spool valve body 65 of the valve V ₂ moves to the left due to the increasing governor pressure Pg.
The oil passage 113 is communicated with the drain oil passage 122, and the oil passage 70 is communicated with the hydraulic oil passage 41c leading to the hydraulic cylinder 40c of the high speed clutch _C3 , and the hydraulic oil passage 41c is isolated from the drain oil passage 123. Accordingly, the middle gear clutch _C2 is released from its engagement state, and the high gear clutch _C3 is pressurized into engagement to establish the gear train _G3 of the high gear gear.

In order to relieve the shock during gear shifting, accumulators 72, 73, 74 are hydraulically connected in parallel to each clutch C ₁ , C ₂ , C ₃ . Further, the drain oil passage 119 is provided with a 1-2 orifice control valve 124, and the drain oil passage 122 is provided with a 2-3 orifice control valve 125.

Back pressure chamber 7 of each accumulator 72, 73, 74
The throttle pressure Pt ₂ from the second throttle valve Vt ₂ is introduced to the throttle valves 7, 78, and 79 via the oil passage 106. This first throttle valve Vt ₂ is inserted between an oil passage 105 branched from the oil passage 53 and the oil passage 106, and includes a spool valve body 107 and a control spring 108 that presses the valve body 107 to the left. and control spring 10
a control piston 109 that supports the outer end of the engine E, and a control cam 110 that rotates in conjunction with an increase in the throttle opening of the engine E and moves the control piston 109 to the left.
and has. When the control piston 109 moves to the left,
The displacement of the spool valve body 1 is controlled via the control spring 108.
07, and the spool valve body 107 moves to the left.
The hydraulic pressure output to the oil passage 106 in conjunction with this leftward movement acts on the left shoulder portion 107a of the spool valve body 107 so as to push the spool valve body 107 back to the right. Through such an operation, the second throttle valve Vt ₂ applies a second throttle pressure Pt ₂ proportional to the throttle opening of the engine E to the back pressure chambers 77 to 77 of each of the accumulators 72 to 74 via the oil passage 106. It will be given to 79. Note that the counterclockwise rotation of the control cam 110 continuously restricts the communication between the drain oil passage 120 and the oil tank R.

During deceleration, the valve body 65 of medium-high speed shift valve _V2
first moves to the right and the speed ratio of the high gear becomes the speed ratio of the middle gear. When the speed further decreases, the valve body 64 of the low-medium speed shift valve V ₁ moves to the right and changes to the speed ratio of the low gear. .

When the manual valve Vm is shifted to a shift position other than the drive position D, for example, to the engine brake position, that is, the first gear holding position, only the low gear clutch _C1 is pressurized and engaged. Further, when shifted to the middle gear holding position or the reverse drive position Re, only the middle gear clutch _C2 is pressurized and engaged, and the middle gear train _G2 or the reverse gear train Gr is established. Especially when shifting to the reverse position Re, the servo motor
The piston 44 of Sm receives pressure oil on its left end surface,
Since the spring chamber 42 is connected to the oil tank R, the piston 44 moves to the right, and as described above, the reverse gear train Gr
is established. Note that among the shift positions of the manual valve Vm, Pk indicates the parking position.

In the oil passage 111, an oil passage 84 leading to the oil tank R is branched from between the one-way throttle 75 and the manual valve Vm, and a creep prevention valve Vc for opening and closing the oil passage 84 is provided in the middle of the oil passage 84. Interposed.
The creep prevention valve Vc has a spool valve body 85, and the spool valve body 85 is housed in a cylindrical valve chamber 86 so as to divide the oil passage 84 into an upstream portion 84a and a downstream portion 84b. As a result, oil chambers 87 and 88 are defined on the left and right sides of the valve body 85. One oil chamber 87 communicates with the upstream portion 84a of the oil passage 84 via a throttle 96, and the other oil chamber 88 communicates with the oil passage ₁ that leads to the second throttle pressure Pt2.
Oil passage 10 branched from 06 and equipped with a throttle 97
6' communicates with each other, and a return spring 89 is housed therein which urges the spool valve body 85 toward the closing side, that is, to the left. The spool valve body 85 is provided with a pair of lands 90 and 91 spaced apart in the axial direction, and an annular groove 92 formed between these lands 90 and 91 is connected to the upstream side of the oil passage 84. 84a is always in communication. One land 91 is connected to the spool valve body 8
5 opens and closes the opening port 95 to the valve chamber 86 in the downstream portion 84b. An oil passage 96 is bored in the spool valve body 85 to communicate the annular groove 92 and the other oil chamber 88 , and the oil passage 96 has an opening area smaller than the throttle 97 on the annular groove 92 side. An orifice 93 is provided, and a check valve 98 is inserted into a portion facing the oil chamber 88. This check valve 98 is held in place by the end of the return spring 89 to prevent backflow of oil from the oil chamber 88 into the annular groove 92.

Here, the first pressure receiving surface 85a for pressing the spool valve body 85 to the closing side, that is, to the left side, has a larger pressure receiving area than the second pressure receiving surface 85b for pressing the spool valve body 85 to the opening side, that is, to the right side. The shoulder portion 99 of the valve body 85 that creates such a difference in pressure receiving area is located at the open port 95, and does not exert any effect on the left-right movement of the valve body 85.

In FIG. 3, the spool valve body 100 of the manual valve Vm has a hydraulic oil passage 4 when shifted to the engine brake position, that is, the first gear holding position.
An annular groove 101 is provided that communicates 1a with the oil passage 43, and at this time, the oil passage 111 communicates with the oil tank R.

Next, to explain the operation of this embodiment, when the manual valve Vm is set to the drive position D and the manual valve Vm is in the drive position D and the user is waiting for a signal at an intersection, etc., there is a valve in the oil passage 84 for operating the low gear clutch _C1 . Hydraulic pressure is acting from the oil passage 111, which acts on the second pressure receiving surface 85b of the spool valve body 82 to move the valve body 85 to the right, and the creep prevention valve Vc is opened. At this time, the throttle pedal is not depressed, so the second throttle pressure Pt ₂ is zero.
The force opposing the right-hand force of the valve body 85 is only the spring force of the return spring 89, and since the oil passage 84 is communicated with the oil tank R, the engagement pressure of the low gear clutch _{C1 is} due to the spring force of the return spring 89. The pressure is maintained at the set pressure Po determined by By setting this set pressure Po to be weaker than the spring force of the return spring 102 of the low speed clutch _C1 , the occurrence of the creep phenomenon is prevented.

Next, when you step on the throttle pedal in this state,
A second throttle pressure Pt ₂ corresponding to the throttle opening is introduced into the oil passage 106, and this acts on the oil chamber 88 via the throttle 97 and the oil passage 106'.
The valve body 85 of the creep prevention valve Vc moves to the closing side, and the oil pressure in the upstream portion 84a of the oil passage 84 increases. Therefore, the low gear clutch _C1 is engaged with a strength that corresponds to the amount of depression of the throttle pedal, making it possible to start the vehicle smoothly. Since the low gear clutch _C1 is engaged in an analog manner in this way, the start of the vehicle can be smoothly and freely controlled by the depression stroke of the throttle pedal.

Referring again to FIG. 3, when the manual valve Vm is shifted to the first gear holding position in order to apply engine braking while the vehicle is running, oil passage 1 is opened as described above.
11 communicates with the oil tank R and is a creep prevention valve Vc
is disconnected so that it is independent of the operation of the low gear clutch _C1 . On the other hand, the hydraulic oil passage 41a communicates with the oil passage 43 via the annular groove 101.
A line pressure Pl is applied from the hydraulic pump P through the hydraulic oil passage 29. Therefore, even if the throttle pedal is taken off, good engine braking can always be obtained, and engine braking can be reliably applied even if the anti-creep valve Vc has failed in its open position. .

In the above embodiment, the oil passage 84 to the creep prevention valve Vc was branched from the oil passage 111;
It may be branched from 8.

As described above, according to the present invention, there is provided a manual valve capable of opening and closing a hydraulic oil passage for supplying hydraulic oil from a hydraulic source to friction engagement elements for starting and engine braking, and a manual valve that branches from the hydraulic oil passage. In a creep prevention device of the type including a creep prevention valve that is installed in an oil passage leading to an oil tank and opens the oil passage when the vehicle is idling, the manual valve is configured to prevent the frictional engagement element and the hydraulic pressure when the manual valve is in the drive position. The hydraulic fluid that establishes a state of communication between the oil pressure source and the hydraulic fluid source is communicated with the creep prevention valve, while maintaining the communication state between the frictional engagement element and the hydraulic pressure source through the hydraulic fluid path when in the first gear holding position. Since an oil passage switching function is provided to cut off the frictional engagement element from the creep prevention valve, by shifting the manual valve to the first gear holding position, the communication state between the hydraulic pressure source and the frictional engagement element can be maintained. At the same time, the anti-creep valve can be isolated from the frictional engagement element, and the frictional engagement element can be effectively operated with high hydraulic pressure (so-called line pressure) from the hydraulic source, and therefore, during engine braking. By simply shifting the manual valve to the 1st gear holding position, the creep prevention function is quickly and reliably released and the engine is always in good condition, without the need for special detection means to distinguish between idling and idling operation. Provides a braking effect.

Furthermore, even in the unlikely event that a failure occurs where the creep prevention valve is left open, good engine braking effects can be quickly and reliably achieved by simply shifting the manual valve to the 1st gear holding position as described above. It will be done.

In addition, in the creep prevention device of the above-mentioned type, which has a relatively simple circuit configuration for preventing creep, only slight changes are made to the oil passage switching structure of the conventional manual valve and the layout of the oil passage piping connected to the valve. The device of the present invention can be easily obtained, and the creep prevention valve itself can be used as is with a conventional relatively simple structure, so the structure of the device as a whole can be made as simple as possible, which can contribute to cost reduction. It is.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; Fig. 1 is a schematic diagram of an automatic transmission for an automobile with three forward speeds and one reverse speed; Fig. 2 is a hydraulic control circuit diagram thereof; and Fig. 3 is a manual valve. FIG. 3 is a hydraulic circuit diagram showing a connection state of oil passages when the engine is in an engine braking position. _C1 ...Low gear clutch as a friction engagement element for starting and engine braking, M...Auxiliary transmission, P...Hydraulic pump as a hydraulic power source, R...
Oil tank, T...torque converter, Vc...creep prevention valve, Vm...manual valve, 84...
Oil passage, 29, 118, 111, 41a... Hydraulic oil passage.

Claims (1)

[Claims] 1 a hydraulic torque converter T, an auxiliary transmission M connected to the torque converter T, and having a frictional engagement element _C1 for starting and engine braking;
Hydraulic oil passages 29, 118, 111, 4 for supplying hydraulic oil from the hydraulic source P to the frictional engagement element _C1
1a and this hydraulic oil passage 29, 118, 111, 4
A creep prevention valve Vc is provided in an oil passage 84 branching from 1a and leading to the oil tank R and opens the oil passage 84 when the vehicle is idling, and the hydraulic oil passages 29, 118, 111, 41a are interlocked with the gear shift lever. In the creep prevention device for a vehicle with an automatic transmission, the manual valve Vm is provided with a manual valve Vm that can be opened and closed, and the manual valve Vm has at least a drive position D and a first gear holding position I set as shift positions. When the valve Vm is in the drive position D, the hydraulic oil passage 29 establishes communication between the frictional engagement element _C1 and the hydraulic pressure source P;
118, 111, 41a as the creep prevention valve
Vc, but when in the first speed holding position I, the hydraulic oil passages 29, 118, 111, 4
It is characterized by being provided with an oil passage switching function so as to maintain the communication state between the frictional engagement element _C1 and the hydraulic power source P by 1a and to shut off the frictional engagement element _C1 from the creep prevention valve Vc. A creep prevention device for vehicles with automatic transmissions.