JPS6123416B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device that enables a hydraulic pump and a hydraulic motor to be directly connected in a timely manner in a continuously variable transmission mainly used in automobiles.

Conventionally, a constant discharge hydraulic pump connected to an input shaft and a swash plate type variable displacement hydraulic motor connected to an output shaft are connected through a hydraulic oil distribution mechanism, and the capacity of the hydraulic motor is changed by changing the inclination angle of the motor swash plate. In a hydraulic continuously variable transmission that allows stepless adjustment of the gear ratio between the input and output shafts, when the tilt angle of the motor swash plate becomes zero and the gear ratio becomes 1:1. In order to prevent a drop in transmission efficiency due to leakage of hydraulic oil and to reduce the load on various bearings due to the thrust load acting on the motor swash plate, the discharge port of the hydraulic pump is closed and a connection is made between the hydraulic pump and the hydraulic motor. A control device that can be directly connected has already been proposed (see Japanese Patent Laid-Open No. 106065/1983).

However, in the conventional method described above, a plug is inserted into the discharge port to close the discharge port of the hydraulic pump, and the insertion part requires a high degree of processing precision, making it difficult to maintain quality during mass production. It is difficult to do so.

The present invention has been proposed in view of the above, and an object of the present invention is to provide a control device for a hydraulic continuously variable transmission that can eliminate the above-mentioned problems and also provide a reliable direct connection between a hydraulic motor and a hydraulic pump. purpose.

In order to achieve this purpose, the present invention
A constant discharge hydraulic pump connected to the input shaft and a swash plate type variable displacement hydraulic motor connected to the output shaft are communicated via a hydraulic oil distribution mechanism, and the hydraulic oil distribution mechanism controls suction and discharge of the hydraulic pump. a distribution board that has a plurality of communication ports of the hydraulic motor opened on one end surface and rotates together with the motor cylinder of the hydraulic motor; and a communication port that is in contact with one end surface of the distribution board and is connected to the discharge port on the high pressure side. A distribution ring forming a low pressure oil chamber communicating between the suction port and the communication port on the low pressure side, and a blocking device for arbitrarily blocking the discharge port. In the hydraulic continuously variable transmission, the shutoff device includes a valve body that is housed in the high-pressure oil chamber and can close and open the discharge port by contacting and separating from the distribution panel, and a servo that drives the valve body. Consists of motor and more,
The servo motor is disposed in the high pressure oil chamber so as to be able to move forward and backward with respect to the discharge port, and is integrally formed with a piston rod having a front end swingably connected to the valve body, and a rear end of the piston rod. a piston having a front oil chamber surrounding the piston rod and a rear oil chamber communicating with the high-pressure oil chamber on the side and rear end sides thereof; a pilot valve capable of selectively communicating the front oil chamber with the rear oil chamber and the atmosphere; the rear end pressure receiving area of the piston is larger than the pressure receiving area of the piston rod;
Further, the valve body is characterized in that it is set smaller than the front end pressure receiving area of the valve body.

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

As shown in FIG. 1, the device of the present invention is a conventionally known hydraulic continuously variable transmission CVT, which is configured by hydraulically connecting a constant discharge amount type swash plate type hydraulic pump P and a variable displacement type hydraulic motor M. A centrifugal pump that is driven in synchronization with the engine-driven pump EP and generates an output hydraulic pressure proportional to the engine rotation speed. The governor CG converts the difference between the force proportional to the throttle valve opening of the engine and the force proportional to the engine rotational speed into a displacement, and determines the control direction of the output control member based on the displacement. A main servo motor MS with a control valve that increases its control power, and a gear shift operation that is manually operated by the vehicle driver to select three positions: manual gear shift position, automatic gear shift position, and neutral position. Device
CSH, a hydraulic change servo motor CHS that controls the tilting of the motor swash plate 11 of the hydraulic motor M in the continuously variable transmission CVT, and a hydraulic clutch servo motor that operates the clutch of the continuously variable transmission CVT.
CLS, the main servo motor MS with the control valve, the change and clutch servo motor CHS,
These servo motors CHS are linked with CLS,
An interlocking operation device OPC that operates and controls the CLS independently or in conjunction with each other, and the clutch servo motor
It consists of a forced clutch-off device CLO that forcibly "clutches off" the CLS, and a traveling drive pump VP that is driven by the running of the vehicle and generates an output hydraulic pressure proportional to the vehicle speed.

First, the configuration of a continuously variable transmission CVT including a swash plate type constant discharge type multi-plunger hydraulic pump P and a swash plate type variable displacement multi-plunger hydraulic motor M will be described.

Incidentally, since this continuously variable transmission CVT is already known, its configuration will be briefly explained. The hydraulic pump P includes a pump cylinder 1 which is passed through an input shaft 3 and is spline-engaged with the input shaft 3, and a plurality of annularly arranged pump cylinders arranged around the rotation center of the pump cylinder 1. It has a large number of pump plungers 5, 5, . . . that are slidably engaged with cylinder holes 4, 4, . On the other hand, the hydraulic motor M includes a motor cylinder 8 which is disposed so as to concentrically surround the pump cylinder 1 and rotate relative to it, and a motor cylinder 8 which is disposed so as to surround the center of rotation of the motor cylinder 8. The motor plunger 10 has a large number of motor plungers 10, 10, .

The inner end of each pump plunger 5 of the hydraulic pump P is rotatably connected via a spherical joint 7 to a pump swash plate 6 fixed at a fixed angle in a motor cylinder 8 of a hydraulic motor M. has been done. Therefore, when the pump cylinder 1 rotates with respect to the motor cylinder 8, a large number of pump plungers 5, 5, . . . are sequentially slid back and forth by the pump swash plate 6, and the discharge stroke and suction stroke are repeated.

The inner end of each motor plunger 10 is connected to a spherical joint 1.
The motor swash plate 11 is rotatably connected to the surface of the motor swash plate 11 via the motor 2. The motor swash plate 11 has integrated trunnion shafts 13 protruding from both sides of its central portion, and these trunnion shafts 13 are pivotally supported by the mission case, and the motor swash plate 11 is rotated relative to the mission case. It is designed to be able to tilt left and right.

Further, a drive gear 14 is integrally formed at the end of the motor cylinder 8 (the left end in FIG. 1) to constitute an output shaft 15.
That is, the rotational force of the output shaft 15 is transmitted to the driving vehicle of the vehicle via a transmission mechanism (not shown). By the way, when the motor cylinder 8 rotates, a large number of motor plungers 10, 10, . . . shift their phases and slide back and forth within the cylinder holes 9, 9, . In this case, the sliding stroke of the motor plungers 10, 10, . . The inclination angle of the motor swash plate 11 is continuously adjusted and controlled by a change servo motor CHS, which will be described later.

The hydraulic pump P and the hydraulic motor M are communicated via a hydraulic passage formed in a distribution panel 17 and a distribution ring 18, which will be described later, and which constitute a hydraulic oil distribution mechanism ds. When the input shaft 3 is rotated by the drive of the engine, the pump cylinder 1 that is spline-engaged with the input shaft 3 is rotated, and high-pressure hydraulic oil is discharged from the cylinder hole 4 that accommodates the pump plunger 5 during the discharge stroke. is the hydraulic oil distribution mechanism described in detail later.
Motor plunger 10 during expansion stroke via ds
The hydraulic oil discharged from the cylinder hole 9 housing the motor plunger 10 during the contraction stroke is supplied to the pump during the suction stroke via the hydraulic oil distribution mechanism DS, which will be described in detail later. The water is returned to the cylinder hole 4 that accommodates the plunger 5.
In this way, while the input shaft 3 is rotating, the hydraulic pump P
The step-down hydraulic oil circulates between the hydraulic motor M and the pump plunger 5 during the discharge stroke, and the pump swash plate 6
The reaction torque applied to the motor cylinder 8 through the motor plunger during the expansion stroke is applied to the motor swash plate 11.
The motor cylinder 8 is rotationally driven by the sum of the reaction torques received from the motor cylinder 8. By controlling the inclination angle of the motor swash plate 11 from the minimum inclination angle (vertical position) Smin to the maximum inclination angle Smax, the capacity of the hydraulic motor M can be changed from zero to a predetermined value, and the input shaft 3 and output Gear ratio between shafts 15 to 1:1
It can be changed steplessly from to the maximum value.

Next, the engine-driven pump EP, which is driven by the engine, will be explained. This is composed of an ordinary gear pump, and its suction port is the oil sump T.
, and its discharge port is communicated with the main oil supply passage 20 . branched into the main oil supply path 202,
On the other hand, 21 is a main servo motor with a control valve, which will be described later.
The other side 22 is connected to a central hydraulic oil passage 44 of the MS, and the other side 22 is connected to a forced clutch-off device, which will also be described later, via an on-off valve V and an oil supply passage 118, which will be described later.
It is communicated with the distribution port 117 of the CLO. Further, a replenishment oil passage 24 is branched from the main oil supply passage 20, and this replenishment oil passage 24 is connected to the continuously variable transmission CVT.
The check valves 26 and 2 pass through the oil passage 25 in the input shaft 3 of the
It is connected to the hydraulic closed circuit of the hydraulic pump P and the hydraulic motor M through the hydraulic pump P, and when the hydraulic oil in the circuit leaks, it can be automatically replenished. In addition, 28 is the engine-driven pump EP
A check valve interposed in the main oil supply path 20 immediately after the discharge port of the
29 is a relief valve connected to the main oil supply path 20 on the downstream side of the check valve 28 .

Next is the centrifugal governor CG, which has a conventionally known structure, is driven in synchronization with the engine-driven pump EP, and is capable of generating an output oil pressure proportional to the engine rotation speed. The input side is supplied with pressure oil from the main oil supply passage 20 via a branch oil passage 30, and the output oil pressure from the output side is supplied via an oil passage 31 to a control valve to be described later. It is connected to the attached main servo motor MS.

Next, a force proportional to the throttle valve opening of the engine and a force proportional to the engine speed are input, and the difference between these forces is converted into a displacement. To explain the configuration of the main servo motor MS with a control valve, which increases the control force when a control method is determined, the control box 33 has valve holes 34 protruding from both sides thereof. A spool valve 35 is fitted in the center of the valve hole 34, and left and right input pistons 36 and 37 are slidably fitted in the left and right ends of the valve hole 34, respectively. The spool valve 35
has a land portion γ in the center and on the left and right sides, respectively.
₂ and γ ₁ , γ ₃ , and the valve hole 34
Inside, from the left side in Figure 1, there are four oil chambers a, b,
It is divided into c and d. Transmission springs 38 and 39 are compressed in the oil chambers a and d, respectively, and the elastic force of these transmission springs 38 and 39 causes the left,
The right input pistons 36 and 37 protrude outside the control box 33. The outer end surface of the left input piston 36 is in contact with the cam surface of a rotary cam 40 that is linked to a throttle valve (not shown) of the engine, and the outer end surface of the right input piston 37 is in contact with the control Box 3
The lower end of a regulating plate 41 whose upper end is fixed to 3 is in contact with the lower end. A stopper 42 is provided on the right side of the control box 33, and this stopper 42 restricts movement of the regulating plate 41 to the left. Further, a bimetal 43 is attached to the regulating plate 41, and the lower part of the regulating plate 41 is bent to the right in FIG. The spool valve 3 due to an increase in idle rotation speed due to fast idle when
In other words, the movement of the spool valve 35 is corrected for variations in engine idling speed. A central hydraulic oil passage 44 is opened in the center of the valve hole 34 and communicates with the engine-driven pump EP via the main oil supply passages 20 and 21. It can be selectively communicated with oil chamber b or c due to the movement. Valve hole 3
The oil chamber b of the valve hole 34 and the left oil chamber e of the servo cylinder 48, which will be described later, are communicated via the left hydraulic oil passage 45, and the oil chamber c of the valve hole 34 and the left oil chamber e of the servo cylinder
The right oil chamber f is communicated with the right oil chamber f via the right hydraulic oil passage 16. Note that the right hydraulic oil passage 46 is further communicated with a replenishment oil passage 47, which will be described later. The valve hole 34 also has a return oil passage 4 that can communicate with the oil chamber a, b or c.
9 is open, and orifices 51 and 52 are interposed in communication passages between the oil chambers a and b and the return oil passage 49. The return oil passage 49 communicates with the oil reservoir T. Furthermore, a control oil passage 53 that can communicate with the oil chamber d is opened in the valve hole 34, and this control oil passage 53 is outputted to the output port of the centrifugal governor CG that generates pressure oil proportional to the engine speed. They are communicated via an oil passage 31.

In the control box 33 below the valve hole 34,
A servo cylinder 48 is formed, and inside this servo cylinder 48 there is a left oil chamber e.
An output member, that is, an output piston 54, which is partitioned into a right oil chamber f and a right oil chamber f, is slidably fitted. Further, the control box 33 has a tip portion of a shift operation lever L, which will be described later, which passes through the center of the servo cylinder 48 and is slidably supported therethrough, and the output piston 54 has a shaft hole 56 formed at its center. The tip of a speed change operation lever L, which will be described later, is slidably inserted into the shaft hole. Further, as will be described in detail later, a first small diameter part l1 is formed at the tip of the speed change operation lever L via a step 58 from the first large diameter part _l2 , and the first small diameter part _l1 is connected to the first small diameter part _l1 . When the output piston 54 comes, a slit is formed between its shaft hole 56 and the first small diameter portion _l1 , and the left oil chamber e and the right oil chamber f are communicated through this slit. ing. Further, in the left end wall of the servo cylinder 48, there is a fitting hole 57 into which the first large diameter portion _l2 can fit when the shift operating rod L moves to the left position, that is, to the automatic shift position D or neutral position N, which will be described later. is drilled.

A piston rod 55 is attached to the output piston 54.
are integrally formed, and this piston rod 55 is
It extends outside the control box 33, and the upper end of an operating arm 132 of an interlocking operation device OPC, which will be described later, is connected to its tip, so that the operating arm 132 can swing left and right as the output piston 54 moves left and right. It's summery.

By the way, when the throttle valve (not shown) is opened to accelerate the engine, the rotating cam 4
0 rotates counterclockwise in FIG. 1, the left input piston 36 moves to the right, and the displacement of the left input piston 36 is converted into force by the transmission spring 38 and transmitted to the spool valve 35. , the spool valve 35 slides to the right by an amount of displacement proportional to the throttle valve opening degree of the engine (not shown). As a result, the central hydraulic oil passage 44 communicates with the left oil chamber e of the servo cylinder 48 via the oil chamber b and the left hydraulic oil passage 45.
On the other hand, the right oil chamber f of the servo cylinder 48 communicates with the return oil passage 49 via the right hydraulic oil passage 46 and the oil chamber c, so that the pressure oil from the engine-driven pump EP flows through the main oil supply passages 20, 21, the central hydraulic oil passage oil passage 44, oil chamber b,
The oil in the right oil chamber f is forced into the left oil chamber e through the left hydraulic oil passage 45, and is returned to the oil sump T through the right hydraulic oil passage 46, oil chamber c, and return oil passage 49. 1, and the output piston 54 can be moved to the right in FIG.

When the engine speed increases due to an increase in the opening of the throttle valve, the centrifugal governor increases in proportion to this.
The output oil pressure of the CG increases, and the increased pressure oil is supplied to the oil chamber d of the valve hole 34 through the output oil path 31 and the control oil path 53, so that the spool valve 35 increases in proportion to the increase in engine speed. slide to the left by the amount of displacement. Then, the central hydraulic oil passage 44 is connected to the servo cylinder 48 via the oil chamber c and the right hydraulic oil passage 46.
On the other hand, the left oil chamber e communicates with the return oil passage 49 via the left hydraulic oil passage 45 and the oil chamber b, so that the pressure oil from the engine-driven pump EP flows into the right oil chamber f. The oil in the left oil chamber e is returned to the oil sump T, and the output piston 54 slides to the left.

Furthermore, when the throttle valve is closed in order to decelerate the engine, the rotary cam 40 rotates clockwise in FIG. The left oil chamber e communicates with the oil sump T and the right oil chamber f communicates with the main oil supply passages 20 and 21 of the engine-driven pump EP, and the output piston 54 is moved to the left. As the engine speed decreases due to the above, the output oil pressure of the centrifugal governor CG decreases in proportion to this, and in complete contrast to the above, the spool valve 35 slides to the right by a displacement amount proportional to the decrease in engine speed. move. Then, the pressure oil from the engine-driven pump EP is again supplied to the left oil chamber e, and the right oil chamber f communicates with the oil sump T, so the output piston 54 slides to the right.

As described above, the spool valve 35 is operated until the opening of the throttle valve, that is, the external force based on the rotation of the rotary cam 40, and the hydraulic pressure from the centrifugal governor CG, that is, the control force proportional to the engine speed are balanced. It can be moved steplessly from side to side. Therefore, for example,
Under conditions where the engine speed is relatively low and the throttle valve opening is relatively large, the spool valve 35 is moved to the right, and following this, the output piston 54 is amplified by the servo motor and moved to the right, Conversely, under conditions where the engine speed is relatively high and the throttle valve opening is relatively small, the spool valve 35 is moved to the left, and the output piston 54 is increased in width by the servo motor and moved to the left. Moved.

Incidentally, the above operation is carried out through the replenishment oil passage 4 as shown in Fig. 1.
This is carried out with the oil supply path 50 leading to 7 being closed by an on-off valve V, which will be described later.

Further, in the operation of the servo motor, when the output piston 54 is located at the first small diameter portion _l1 of the speed change operation lever L, the left oil is passed through the gap between the first small diameter portion _l1 and the shaft hole 56 of the output piston 54. Since the chamber e and the right oil chamber f communicate with each other, oil freely flows between the chambers e and f, and the output piston 54 is moved by the difference in area between the left and right sides. Since the left side area A ₁ of the output piston 54 is larger than the right side area A ₂ , the output piston 54 is moved to the left until it reaches the first large diameter portion l ₂ of the speed change operation lever L. As will be explained in detail later in the explanation section, this is true for the continuously variable transmission.
When operating the CVT manually, use the gear shift lever L.
When the piston 54 is manually moved left and right, the output piston 54 can be moved to follow the movement.

The reason why orifices 51 and 52 are provided between the oil chamber a of the valve hole 34 and the return oil passage 49 and between the oil chamber b and the return oil passage 49 is as follows. That is, when the throttle valve of the engine is suddenly opened and the rotary cam 40 suddenly rotates counterclockwise, the orifice 51 prevents the oil in the oil chamber a from being rapidly discharged, and the oil in the oil chamber a is momentarily The airtight state is established, and the rightward movement of the left input piston 36 hydraulically closes the spool valve 35.
The control force of the output piston 54 is corrected to increase the control force of the output piston 54, and the acceleration performance of the vehicle is improved as will be described in detail later. Further, when the throttle valve is rapidly closed and the rotating cam 40 rapidly rotates clockwise, the left input piston 36 is released from the rotating cam 40, but the leftward movement of the spool valve 35 is caused by oil discharged from the orifice 52. Therefore, the output piston 54 moves slowly to the left, and the reduction ratio of the continuously variable transmission CVT gradually decreases. When the engine suddenly decelerates, the sudden decrease in the reduction ratio causes the vehicle to momentarily stop. This is to prevent the danger of acceleration.

The speed change operation device CSH is constructed by guiding and supporting a speed change operation rod L by a bearing portion 60 formed in the transmission case so that it can slide left and right, and the free end of the speed change operation rod L is connected to a handle (not shown). They are linked together so that the driver can manually slide them left and right.

The speed change operation lever L has a first small diameter part l 1 , a first large diameter part l ₂ , a second small diameter part l ₃ and a second large diameter part from the inner end to the outer end, that is, from left to _right in FIG. l ₄ , and there is a step difference of 58 between the first small diameter part l ₁ and the first large diameter part l ₂ .
is formed. and a first small diameter part l ₁ and a first large diameter part
l ₂ is inserted into the aforementioned servo motor MS with control valve.

Between the bearing portion 60 and the shift operation lever L, the shift operation lever L is positioned at the manual shift start position shown in FIG.
Ma, automatic shift position D and neutral position N
A click stopper 61 is provided for locking in three positions.
1 are three notches 62 formed on the gear shift operation lever L;
63 and 64, a locking ball 65 provided on the bearing portion 60, and a spring 66 that springs the locking ball 65 toward the speed change operation lever L. Thus, the range between the manual shift start position Ma and the automatic shift position D becomes the manual shift range Mγ of the shift operation lever L. In FIG. 1, the manual shift start position Ma, the manual shift range Mγ, the automatic shift position D, and the neutral position N are all shown with the center line of the click stopper 61 as a reference.

The speed change operation lever L and the bearing portion 60 of the transmission case together constitute an on-off valve V that controls opening and closing of the oil passage of the present invention. The structure of this on-off valve V will be explained below.The second large diameter portion _l4 of the speed change operation lever L is connected to the engine driven pump.
An oil supply passage 118 that communicates with EP and a traveling drive pump VP, which will be described in detail later, and an oil supply passage 50 that communicates only with the traveling drive pump VP cross adjacent to each other, and these oil supply passages 118 and 50 are When the shift operation lever L is shifted to the "manual shift range Mγ" and the "automatic shift position D", the second large diameter portion
It is designed to be closed and blocked by l ₄ . Further, when the gear shift operating lever _L is shifted to the leftmost position in FIG. 68, and pressure oil from the engine drive pump EP and the travel drive pump VP, which will be described later, is introduced into the right chamber i of the cylinder 113 of the forced clutch-off device CLO, which will be described later, through the oil supply path 118. Clutch servo motor CLS, which will be described later
force the clutch off.

Pressure oil from the travel drive pump VP, which will be described later, is supplied to the right oil chamber f of the servo cylinder 48 through the oil supply path 50, the replenishment oil path 47, and the right hydraulic oil path 46, and is supplied onto the first large diameter portion _l2 . When a certain output piston 54 is moved to the left limit position, that is, the TOP position (the gear shift operation lever L is in the left limit position, that is, the neutral position N), and then returned from the "neutral position N" to the automatic or manual shift position, there is a sudden sudden shift. The engine brake load is not increased.

The motor swash plate 11 is arranged vertically as shown by the chain line in FIG.
A hydraulic change servo motor CHS for tilting from the TOP position Smin to the maximum tilted LOW position Smax shown by the solid line in FIG. 1 is provided in the mission case. Next, this change servo motor
To explain the structure of the CHS, it consists of a servo cylinder 70 that is fixedly supported by a transmission case, a servo piston 71 that divides the inside of the cylinder into a left oil chamber g and a right oil chamber h, and a servo piston 71 that divides the inside of the cylinder into a left oil chamber g and a right oil chamber h. A piston rod 74, which is integral with the servo piston 71, penetrates through the servo cylinder 70 and has a pilot valve 72 whose distal end slides into a valve hole 73 formed in the servo piston 71. The motor swash plate 11 is connected to the motor swash plate 11 by a pin. The left oil chamber g of the servo cylinder 70 is communicated with a high pressure oil passage 77 via a passage 76 formed in the servo cylinder 70, and high pressure oil flowing in the high pressure oil passage 77 acts thereon. By the way, in the high pressure oil passage 77, a hydraulic pump P is installed when the engine is driven.
High-pressure hydraulic oil from the clutch servo motor CLS
During engine braking, constant pressure oil, which is lower than the high pressure hydraulic oil, is supplied from the engine-driven pump EP through the clutch servo motor CLS. . Further, this high pressure oil passage 77 is communicated with the main oil supply passage 22 via a relief valve R, and when the oil pressure in this high pressure oil passage 77 exceeds a predetermined value, the relief valve R is activated. Further, the valve hole 73 is communicated with the oil reservoir T through its discharge passage 78. The servo piston 71 has a right oil chamber h and a valve hole 73 in response to the rightward movement of the pilot valve 72.
A discharge passage 78 is opened to the oil sump T via the oil sump T, and a supply passage 79 is provided to communicate the right oil chamber h with the left oil chamber g in response to leftward movement of the pilot valve 72. Therefore, the servo piston 71 is actuated by the pressure oil in the high pressure oil passage 77 so as to follow the left and right movements of the pilot valve 72, thereby moving the motor swash plate 11 to the solid line in FIG. From the maximum tilt position shown, i.e. LOW position Smax, to the minimum tilt position (vertical position) shown by the chain line in Figure 1, i.e. TOP
It can be shifted steplessly up to position Smin. In that case, the hydraulic pump P is driven by the engine.
When the motor swash plate 1 is operated, the high pressure hydraulic oil is supplied to the high pressure oil passage 77 through the clutch servo motor CLS, which will be described later.
1 can be made sensitive, and during engine braking, pressure oil with a lower pressure than the hydraulic oil from the engine-driven pump EP passes through the clutch servo motor CLS, which will also be described later, to the oil. 77, the response tilting of the motor swash plate 11 can be slowed down to prevent sudden engine braking.

A cylinder 81 is fixed to one end wall 80 of the transmission case on the right side of the continuously variable transmission CVT. The distribution ring 18 is eccentrically supported at the inner end of the cylinder 81, and the inner end surface of the distribution ring 18 is in oil-tight contact with one end surface of the distribution plate 17. The distribution ring 18 divides a sealed hollow chamber 83 defined within the motor cylinder 8 into an inner chamber 83in and an outer chamber out. On the other hand, the distribution panel 17 has a discharge port 84 and a suction port 8.
5 is bored, and the discharge port 84 is
The cylinder hole 4 on the discharge stroke side of the hydraulic pump P can communicate with the inner chamber 83in, and the suction port 85 can communicate the cylinder hole 4 on the suction stroke side of the hydraulic pump P with the outer chamber 83out. It's becoming like that. Further, in addition to the discharge port 84 and the suction port 85, a large number of communication ports 86, 86... are bored in the distribution board 17, and these communication ports 86, 86..., together with the motor cylinder 8, As the rotating distribution board 17 rotates, the cylinder holes 9, 9, . . . of the motor cylinder 8 can be communicated with the inner chamber 83in or the outer chamber 83out.

Therefore, when the pump cylinder 1 rotates with the rotation of the input shaft 3, the high-pressure hydraulic oil generated by the discharge stroke of the pump plunger 5 flows from the discharge port 84 to the inner chamber 83in, and is in communication with it. The hydraulic fluid flows into the cylinder hole 9 of the motor plunger 10 on the expansion stroke through the communication port 86 located at the cylindrical part 83, giving thrust to the motor plunger 10, while the hydraulic oil discharged by the motor plunger 10 on the contraction stroke communicates with the outer chamber 83uot. Returns to the cylinder hole 4 of the pump plunger 5 during the suction stroke through the communication port 86 and the suction port 85,
Power is transmitted from the hydraulic pump P to the hydraulic motor M by circulating the hydraulic oil in this manner.

In the above description, the inner chamber 83in to which the discharge port 84 opens constitutes the high-pressure oil chamber of the present invention, and the outer chamber 83out to which the suction port 85 opens constitutes the low-pressure oil chamber of the present invention.

By the way, in the cylinder 81, (a) the discharge side and the suction side of the hydraulic pump P are short-circuited, and high-pressure hydraulic oil is not supplied to the hydraulic motor M, so that the hydraulic motor M is deactivated; (b) A "clutch-on" state in which high-pressure hydraulic fluid is freely circulated from the hydraulic pump P to the hydraulic motor M; (c) A "clutch-on" state in which high-pressure hydraulic fluid is freely circulated from the hydraulic pump P to the hydraulic motor M by adjusting the opening degree of the short circuit. "Half-clutch" state (d) where the flow of hydraulic oil to the hydraulic pump P is completely shut off, the pump plunger 5 is hydraulically locked, and the pump cylinder 1 and motor cylinder 8 are connected. “Hydraulic pump and hydraulic motor directly connected” to rotate as one unit
It is equipped with a hydraulic clutch servo motor CLS that can selectively take the above four states.

The structure of this clutch servo motor CLS will be explained below. The cylinder 81 has a center hole 89 and a plurality of (two in the illustrated example) short-circuit ports 87 and 88 penetrating its side wall. The inner open ends of these shorting ports 87 and 88 are communicated with the inner chamber 83in through the center hole 89 of the cylinder 81, and the outer open ends of these ports 87 and 88 are formed on the outside of the cylinder 81. The outer chamber 83 passes through the oil passage groove 90.
It is connected to out. Said shorting port 87, 8
The inner open end of the cylinder 81, that is, the open end of the cylinder 81 toward the center hole 89, is slightly offset in the axial direction of the cylinder 81 (in the figure, the short-circuit port 87 is slightly offset to the left with respect to the short-circuit port 88).

The center hole 89 of the cylinder 81 has a piston 96 and its front end surface (the left end surface in FIGS. 1 and 2).
A clutch valve 92 consisting of a piston rod protruding from the piston rod is slidably fitted therein, and when the clutch valve 92 slides to the left in the figure, the shorting ports 87 and 88 are sequentially closed, and when the clutch valve 92 slides to the right, the short-circuit ports 87 and 88 are sequentially closed. The shorting ports 87 and 88 are opened sequentially. Further, a tapered surface 93 is formed on the outer periphery of the inner end surface of the clutch valve 92 so that the short-circuit ports 87 and 88 can be opened slowly.

A valve rod 94 is screwed onto the tip of the clutch valve 92, and a poppet-shaped valve body 95 is swingably connected to the spherical end of the valve rod 94. Valve body 95
is oil-tight on one end surface so as to close the open end of the discharge port 84 formed in the distribution panel 17 when the clutch valve 92 moves further to the left beyond the "clutch-on" state as described later. The oil flow from the discharge port 84 to the inner chamber 83 inches can be blocked.

Now, when the clutch valve 92 is at the right end position as shown in the figure, the short-circuit ports 87 and 88 are open and in communication with the inner chamber 83in, and the high pressure discharged from the discharge port 84 of the distribution board 17 is The hydraulic oil immediately short-circuits to the suction port 85 of the hydraulic pump P, and is not supplied to the hydraulic motor M. Therefore, in this state, the hydraulic motor M is not operated and is in a so-called "clutch-on" state.

The clutch valve 92 then slides to the left in the figure,
When both the short-circuit ports 87 and 88 are closed, a flow of hydraulic oil occurs between the hydraulic pump P and the hydraulic motor M as described above, so the input shaft 3 and the output shaft 15 are hydraulically connected. The clutch valve 92 changes from the above-mentioned "clutch-off" state to the "clutch-on" state.
In the process of transitioning to the state, the short circuit port 8
The opening degrees of 7 and 88 are gradually narrowed down so that a part of the hydraulic oil from the discharge port 84 flows to the hydraulic motor M, and the other part is short-circuited to the suction port 85 of the hydraulic pump P. This state is the so-called "half-clutch" state. By the way, in this case, the short circuit port 8
7 and 88 are offset in the axial direction of the cylinder 81, that is, in the sliding direction of the clutch valve 92, and a tapered surface 93 is formed on the outer periphery of the inner end surface of the clutch valve 92, so that the short-circuit ports 87, 88 is opened and closed slowly. This allows for smoother clutch switching and a wider half-clutch area, allowing for smoother vehicle starting. Further, when the clutch valve 92 is further slid to the left beyond the above-mentioned "clutch-on" state, the valve body 95 comes into close contact with the end face of the distribution plate 17, and in particular, this close contact is ensured by the oscillating movement of the valve body 95, The discharge port 84 opened there is surely closed to block the flow of hydraulic oil from the discharge port 84 to the inner chamber 83 inches, and the "hydraulic pump and hydraulic motor are directly connected".
state, the pump plunger 5 is hydraulically locked and the pump plunger 5 is moved from the pump cylinder 1 to the pump plunger 5.
Motor cylinder 8 via group and pump swash plate 6
can be mechanically driven. Therefore, the thrust applied to the motor swash plate 11 of the motor plunger 10 disappears, and the burden on various members such as bearings due to the thrust can be reduced. Therefore, in this "hydraulic pump and hydraulic motor direct connection" state, the motor swash plate 11
This is done when the gear ratio is 1:1 with the input shaft upright, that is, when the gear ratio is at the "TOP position Smin", and it improves the efficiency of power transmission from the input shaft 3 to the output shaft 15. can.

Next, the configuration for controlling the clutch valve 92 to move left and right in the center hole 89 of the cylinder shaft 81 as described above will be explained with reference to FIG. 2. A front oil chamber 97 surrounding a clutch valve 92 on the rear end side and a rear oil chamber 101 surrounding a pilot valve 105 to be described later.
A rear oil chamber 101 thereof is communicated with the inner chamber 83in through an oil passage 102 formed in the ordinary clutch valve 92 and an oil passage 103 formed in the valve rod 94. When the engine is running, a hydraulic pump P is installed in the oil chamber 11.
A part of the high-pressure hydraulic oil circulating through the hydraulic motor M is transferred from the inner chamber 83 inches to the oil passages 103, 102.
During engine braking, part of the pressure oil (lower pressure than the hydraulic oil) from the engine-driven pump EP is also supplied through the oil passages 103 and 103.
It is designed to be constantly supplied through 102. The oil chamber 101 also communicates with the high-pressure oil passage 77 described above.

A piston 9 is provided at the base end of the clutch valve 92.
A blind hole 98 that opens at the rear end portion 100 of 6 is bored. This blind hole 98 and the front oil chamber 97 communicate with each other through a communication hole 99 formed in the clutch valve 92.

An escape groove 104 is formed on the inner peripheral surface of the blind hole 98 formed at the base end of the clutch valve 92. A pilot valve 105 is inserted into the blind hole 98 and passes through one end wall 80 of the mission case. The tip of the pilot valve 105 has a land portion 106 that slides into the blind hole 98.
A small diameter portion 107 is formed behind the land portion 106 (to the right in FIG. 2). The pilot valve 105 is also provided with an oil sump communication hole 108, which has one end opening into the blind hole 98 and the other end communicating with an oil sump (not shown) under atmospheric pressure.

The pilot valve 105 is equipped with an operating lever 11, which will be described later.
0 are connected to each other, and can be moved from side to side by the operation of this operating lever 110. By the way, when the pressure-receiving area of the end face of the valve body 95: A, the cross-sectional area of the piston 96: B, the cross-sectional area of the piston rod, that is, the clutch valve 92: C, the cross-sectional area of the pilot valve 105: D, then A>B-D B-D> The dimensions of each part are determined so that the inequality C is satisfied.

Now, when the pilot valve 105 is moved to the left in FIGS. 1 and 2 in order to "clutch on", the small diameter portion 107 of the pilot valve 105 is completely inserted into the dead hole 98, so that the high pressure from the discharge port 84 is removed. The hydraulic oil flows into the rear oil chamber 101 through the oil passages 103 and 102, and the rear end surface 10 of the piston 96.
At the same time, the hydraulic oil also applies hydraulic pressure to the left end surface of the clutch valve 92. Since the pressure receiving area of the rear end surface of the piston 96 is B-D and the pressure receiving area of the front end surface of the clutch valve 92 is C, the clutch valve 92 moves to the left due to the above-mentioned inequality B-D>C. become. Therefore, when the pilot valve 105 moves to the left to "clutch on", the clutch valve 92 follows in the same direction due to the hydraulic pressure of the hydraulic oil, and the clutch valve 92 closes both the short-circuit ports 87 and 88. Finally,
As mentioned above, it becomes a "clutch-on" state.

Also, when the pilot valve 105 is moved to the right to "clutch off", the pilot valve 10
Since a part of the small-diameter portion 107 of No. 5 comes out from the dead end hole 98, the high-pressure hydraulic oil applies hydraulic pressure to the rear end surface 100 of the piston 96, while also applying pressure to the front end surface (left end surface) of the clutch valve 92. In addition, the hydraulic pressure flows into the front oil chamber 97 through the dead end hole 98 and the communication hole 99, and acts on the front end surface of the piston 96, increasing the pressure receiving area for moving the clutch valve 92 to the left. is B-D, whereas
The pressure receiving area for moving the clutch valve 92 to the right is B. Therefore, as a matter of course, B>B-D causes the clutch valve 92 to move to the right, resulting in the aforementioned "clutch-off" state as shown in FIGS.

Further, the clutch valve 92 is further moved to the left from the above-mentioned "clutch-on" state, and the valve body 95 is brought into contact with the end surface where the discharge port 84 of the distribution board 17 opens, and the above-mentioned "hydraulic pump, hydraulic motor directly connected" state is achieved. In this case, high-pressure hydraulic oil (equal pressure to the hydraulic pressure in the oil chamber 101) from the discharge port 84 acts on the valve body 95 only on its front end surface having the pressure receiving area A. On the other hand, the piston 96
High-pressure hydraulic oil in an oil chamber 101 acts on the right end portion 100 having a rear end pressure receiving area B-D. Therefore, due to the inequality A>B-D, a biasing force is applied to the valve body 95 to move it to the right. By the way, if the valve body 95 moves slightly to the right, the biasing force of the valve body 95 is released, so that the valve body 95 is again pressed against the end face of the distribution board 17, and the same operation is repeated little by little thereafter. Therefore, by setting the pressure-receiving areas of A, B, and C to predetermined values by satisfying the inequality, it is possible to maintain the so-called "hydraulic floating support" state, so that the distribution plates 17 that rotate relative to each other can be maintained. It is possible to maintain a good oil-tight state between the valve body 95 and the valve body 95 while minimizing wear on the sliding surfaces and leakage of hydraulic oil from between the sliding surfaces.
The valve body 95 and the clutch servo motor CLS
This constitutes a blocking device 200 of the present invention for arbitrarily blocking the discharge port 84.

Behind the hydraulic clutch servo motor CLS, the transmission case includes an operating lever 110.
is pivotally supported 111 so as to be able to swing left and right, and the rear end of the pilot valve 105 of the clutch servo motor CLS is connected 112 to the upper end of this operating lever 110.

A forced clutch-off device CLO is connected to the lower end of the operating lever 110 121 . This forced clutch-off device CLO is configured to forcibly “clutch-off” the clutch device when the shift operating lever L is shifted to the “neutral position”, regardless of the interlocking operating device OPC, which will be described later. The configuration of this device CLO will be explained below. A cylinder 113 is disposed on the lower right side of the operating lever 110, and inside this cylinder 113, a left oil chamber i and a right oil chamber j are provided.
A piston 114 is fitted to be slidable left and right. A piston rod 115, which is integral with the piston 114, passes through the left end wall of the cylinder 113 and projects to the outside, and the lower end of the operating lever 110 is connected 121 to its tip. A compression spring 116 is compressed in the left oil chamber i, and when the compression spring 116 is biased so as to slide the piston 114 to the right, it also pushes against the operating lever 110 as described above. It is biased to rotate clockwise and has two different operations.
Further, a circulation port 117 is bored in the right end wall of the cylinder 113, and an oil supply passage 118 connected to the engine drive pump EP or the travel drive pump VP, which will be described later, is communicated with the circulation port 117, as will be described in detail later. When the gear shift lever L is in the neutral position N, the pump EP or
Pressure oil from VP flows into the right oil chamber j of cylinder 113.
It has come to act on Furthermore, cylinder 1
A reed valve 119 that is pressed into contact with the circulation port 117 is fixed to the inner wall of the right end of the reed valve 13, and a small hole 120 is bored in the reed valve 119.
The right oil chamber j connects to the circulation port 1 through this small hole 120.
It communicates with an oil supply path 118 via 17. Therefore, when the aforementioned gear shift operation lever L is shifted to the "neutral position N", the engine-driven pump
Pressure oil from the EP or travel drive pump VP passes through the on-off valve V, enters the right oil chamber j of the cylinder 113 via the oil supply path 118, the circulation port 117 and the reed valve 119, and moves the piston 114 against the force of the compression spring 116. Since it slides to the left against the force, the operating lever 110 is forcibly rotated clockwise, and the pilot valve 72 of the clutch servo motor CLS is
It is forcibly moved to the right, that is, to the "clutch off" side, so that it can be forcibly "clutched off" during neutral operation. Further, when a gear shift operating lever L, which will be described later, is shifted from a neutral position N to an automatic gear shift position D, and communication between the pump EP or VP and the oil supply passage 118 is cut off by the on-off valve V, pressure oil is stored in the right oil chamber j. Since the piston 114 is no longer supplied with the compression spring 1
At this time, the pressure oil in the right oil chamber j is squeezed through the small hole 120 and flows through the oil supply path 118 to the return oil path 122, so that the operating lever 110 rotates slowly counterclockwise, and the "clutch-on" operation of the clutch servo motor CLS is performed in a damping manner.

The pilot valve 72 of the change servo motor CHS and the pilot valve 105 of the clutch servo motor CLS are provided with an interlocking operating device OPC at a suitable location within the mission case to operate them individually or in conjunction with each other. The configuration of this device OPC will be explained below. A support shaft 130 is supported on the mission case behind the change servo motor CHS, and this support shaft 130 includes an operation cam 131, an operation arm 132, and an operation arm 133 are supported so that they can rotate integrally, of which the actuating arm 13
2 is the output piston 5 of the main servo motor MS mentioned above.
It is connected 141 to the rear end of the piston rod 55 of No. 4.

The operation cam 131 has a generally ladle-like overall shape, and at its base end there is a first cam surface c ₁ that is an arcuate surface with a short radius γs centered on the axis O of the support shaft 130 . The axis O of the support shaft 130 is located at the tip.
A second cam surface c ₂ is formed as an arcuate surface with a long radius γl centered at , and a second cam surface c 2 is formed as an arcuate surface with a major axis γl as the center, and a second cam surface c _{2 is formed as an inwardly concave hyperbola between the upper surface ends of the first and second cam surfaces c 1} and c ₂ . Three cam surfaces _c3 are formed. Operation cam 13
1 and the change servo motor CHS.
A tension spring 134 is stretched between the base ends of the pilot valve 72, and the tensile force of this tension spring 134 causes the base end surface of the pilot valve 72 to
It is biased so as to come into pressure contact with the cam surface of No. 1.

As shown in FIG. 1, the pilot valve 72
When the base end of the pilot valve 72 is in contact with the second cam surface _c2 , the pilot valve 72 is held at that position without moving even if the operating cam 131 rotates, and the motor swash plate 1
1 is at the maximum tilt position Smax, that is, the "LOW position". When the operating cam 131 is rotated _{counterclockwise} in FIG. The valve 72 moves to the right following its hyperbolic third cam surface _c3 . Therefore, the motor swash plate 11 tilts rightward toward the TOP side. Furthermore, the operation cam 131
When rotates counterclockwise, the base end of the pilot valve 72 comes into contact with the first cam surface _c1 , and the motor swash plate 11 comes to the minimum tilt position (upright position) Smin, that is, the "TOP position". And operation cam 131
Even if the valve rotates further, the pilot valve 72 no longer moves.

A clutch operating rod 1 is provided at the tip of the operating arm 133.
The upper ends of 35 are connected. Clutch operating lever 1
35 is a guide hole 137 formed in the mission case.
It extends vertically through the clutch servo motor CLS, and its lower end reaches the rear of the clutch servo motor CLS. An inclined cam surface 138 is formed on one side of the lower end thereof, and a roller 139 pivotally supported on the upper half of the operating lever 110 is provided on the inclined cam surface 138.
are pressed together by the elastic force of the compression spring 116 within the cylinder 113. As mentioned above, the clutch servo motor CLS is mounted on the upper end of the operating lever 110.
The rear end of the pilot valve 105 is connected to a connection 112. Therefore, when the support shaft 130 rotates, the clutch operating rod 135 is rotated via the operating arm 133.
is operated to raise and lower. When the clutch operating lever 135 rises, the roller 139 moves to the right along the inclined cam surface 138, so the operating lever 110 is rotated clockwise and the pilot valve 105 moves to the right, that is, to the "clutch off" side. Also, when the clutch operating lever 135 is lowered, the roller 139 moves to the left along the inclined cam surface 138, so the operating lever 110 is rotated counterclockwise, and the pilot valve 105 is moved to the left, that is, "clutch on". Move to the side.

At the bottom of the clutch operating lever 135, on the opposite side from the inclined cam surface 138, there is a bimetal 14.
This bimetal 140 acts to bend the lower half of the clutch operating rod 135 to the right in cold weather, and the pilot valve 105 is positioned slightly to the right in cold weather. The clutch servo motor CLS is corrected so that even if the engine idling speed increases due to fast idle, the clutch servo motor CLS does not operate to the "clutch on" side. Correction for the increase in temperature is made by sensing the temperature at that time.

Next, we will explain the traveling drive pump VP, which is driven by obtaining power from the traveling rotating parts of the vehicle when the vehicle is running.This is composed of a normal gear pump, and its suction side is communicated with the oil sump T. A discharge passage 150 is communicated with the discharge side, and this discharge passage 1
50 is branched into first and second sub-oil supply passages 151 and 152, and the first sub-oil supply passage 151 communicates with the replenishment oil passage 47 of the main servo motor MS via the on-off valve V and the control valve. Further, the second sub-oil supply passage 152 is communicated with the main oil supply passage 22 which is connected to the engine-driven pump EP.

This traveling drive pump VP has three functions: (1) When the vehicle is running on high power, this traveling pump VP is operated in parallel with the engine driven pump EP, so that their Even if one of them breaks down, there will be no problem with driving and it will be fail-safe. (2) When a vehicle is forced to drive, or when the engine stalls during neutral coasting, etc.
When the necessary high-pressure hydraulic oil cannot be obtained from the engine-driven pump EP, the travel-driven pump VP can supply pressure hydraulic oil to the required location. (3) When the speed change operation lever L is shifted to the neutral position N, pressure oil from the traveling drive pump VP is supplied into the right oil chamber f of the servo cylinder 48 to move the output piston 54 to the left end position and start the motor. Swash plate 11
can be forcibly tilted to the TOP position, preventing excessive engine braking when driving again, allowing a smooth switch from neutral driving to driving driving without shock. .

Next, the functions of the "automatic drive", "manual drive" and "neutral" operations of the present invention will be explained in order.

[] Automatic drive Shift the shift operating lever L to the "automatic shift position D" shown by the two-dot chain line in FIG. At this position D, the locking ball 6 of the click stopper 61
5 fits into the notch 63 to lock the gear shift operation lever L. By the way, in this "automatic shift position D", the left end of the first large diameter portion _l2 of the shift operation lever L is in the insertion hole 5.
7, and within the servo cylinder 48, the first large diameter portion _l2 is located over its entire length, so that no matter where the output piston 54 is located within the servo cylinder 48, the first large diameter portion l2 is located within the servo cylinder 48. ₂ are rubbed together. Further, the on-off valve V is in the closed position, and the oil supply to the forced clutch-off device CLO is cut off, and the oil supply to the supply oil passage 47 is also cut off.

When an engine throttle valve (not shown) is opened or closed in order to accelerate or decelerate the engine, the rotating cam 40 that is linked therewith rotates counterclockwise or clockwise to move the input piston 36 to the right or left. The displacement of the left input piston 36 is converted into force by the transmission spring 38 and moves the spool valve 35, thereby supplying the hydraulic oil from the engine-driven pump EP to the servo cylinder 48 and the output piston 54 as described above. Provides a control force in the right direction according to the opening degree of the throttle valve. On the other hand, the centrifugal governor CG generates an output hydraulic pressure proportional to the engine rotational speed, so in response to the hydraulic pressure, it supplies the hydraulic oil to the servo cylinder 48 via the spool valve 35, and outputs hydraulic oil proportional to the engine rotational speed. Piston 5 outputs control force in the direction
Give to 4. In this way, the output piston 54
is continuously moved left and right until the point where the rightward control force corresponding to the opening degree of the throttle valve and the leftward control force corresponding to the engine speed are balanced.

By the way, in the state shown in FIG. 1, the output piston 54 is at the right end position, the operating cam 131 is rotated most clockwise, and the motor swash plate 1 of the continuously variable transmission CVT is
1 is at the maximum inclination position Smax, that is, the LOW position, and its reduction ratio is at its maximum.

When the engine is currently being driven and the throttle valve opening is small and the engine speed increases, the output piston 54 of the main servo motor MS with control valve begins to move to the left, and the operating cam 131 is moved to the left via the operating arm 132. However, in the range in which the output piston 54 moves from position A to position B in Figure 1, the pilot valve 72 of the change servo motor CHS slides on its second cam surface _c2 even though the operating cam 131 rotates counterclockwise. The change servo motor CHS does not operate, but the operating arm 1
33 is rotated to the left, so the clutch operation lever 135
is lowered, the pilot valve 105 of the clutch servo motor CLS moves to the left, and the clutch servo motor CLS moves to the left.
As mentioned above, the CLS goes through the "half-clutch" state and then "clutches on." This allows continuously variable transmission
A hydraulic pump P and a hydraulic motor M of the CVT are hydraulically connected.

When the engine rotational speed further increases and the output piston 54 moves to the left beyond the position shown in FIG. When the third cam surface _c3 is reached, the change servo motor CHS enters the operating state, and the motor swash plate 11 can be tilted. In this case, as detailed above, the pilot valve 72, that is, the motor swash plate 11, is tilted hyperbolically by the third cam surface _c3 in response to the linear left-right movement of the output piston 54, matching the output characteristics of the engine. Gear shifting operation becomes possible.

When the output piston 54 is moved left and right in the range shown in FIG. For example, under conditions where the engine speed is relatively low and the throttle valve opening is relatively large, the output piston 54 occupies a rightward position in the range of the lo-ho, and accordingly The change servo motor CHS automatically tilts the motor swash plate 11 to the LOW position or a position close to the LOW position to increase the reduction ratio. On the other hand, under conditions where the engine speed is relatively high and the throttle valve opening is relatively small, the output piston 54 occupies a leftward position in the range of the loaf, and the change servo motor CHS accordingly shifts the motor tilt. The plate 11 is automatically tilted to or near the TOP position (vertical position), and the reduction ratio is reduced. In the range of movement of the output piston 54, the clutch operating lever L135 is lowered, and the clutch servo motor CLS is of course in the "clutch-on" state.

Also, the TOP position, that is, the output piston 54
When the servo motor CHS moves further from the C position to the left position and reaches the H position range, the change servo motor CHS
The right end of the pilot valve 72 reaches the right end position by contacting the first cam surface _c1 of the operating cam 131, and even if the operating cam 131 rotates, the pilot valve 72 remains at the right end position, causing the motor to tilt. The board 11 remains in the TOP state. In this state, the clutch operating lever 135
The roller 139 of the operating lever 110 is lowered to the lowest position.
comes into contact with the rod-shaped part of the clutch operating rod 135, and the pilot valve 105 of the clutch servo motor CLS moves further to the left from the "clutch on" position, and the valve body 95 closes the discharge port 84 of the distribution board 17. As mentioned above, when the hydraulic pump P and the hydraulic motor M of the continuously variable transmission CVT are in a locked state and the motor swash plate 11 is in the TOP position, that is, the gear ratio is 1:1, the continuously variable transmission CVT is activated. It can be hydraulically locked to increase the power transmission efficiency between the input shaft 3 and the output shaft 15 as detailed above.

Furthermore, when the output piston 54 moves to the right from the position C in Figure 1, the "hydraulic pump and hydraulic motor are directly connected" state is released and the motor swash plate 11 is moved from the TOP position to the LOW state after returning to the "clutch-on" state. Needless to say, it will start tilting to the side.

Note that the advantages of the presence of the orifices 51, 52 and the bimetal 43 in the operation of the main servo motor MS with a control valve have already been described, so they will not be described in this section.

[] Manual drive operation In Fig. 1, the manual shift start position Ma is shown for the shift operation lever L, and from this position Ma, the shift operation lever L is shifted leftward within the length range of the manual shift range Mγ. is the movement range of the speed change operation lever L during manual drive. In this manual drive operation as well, the on-off valve V is in a closed state as in the automatic drive operation. As is clear from FIG. 1, a portion of the first small diameter portion l ₁ and the first large diameter portion l ₂ of the speed change operation lever L are located within the servo cylinder 48. When the engine is operated and its rotational speed increases, the output piston 5
4 moves to the left, but at this time its output piston 5
4 moves to the left beyond the step 58 between the first small diameter portion l ₁ and the first large diameter portion l ₂ , the left oil chamber e and right oil chamber f of the servo cylinder 48 move into the shaft hole 5 of the output piston 54 .
6 to communicate with each other. In this case, the left pressure receiving area A ₁ of the output piston 54 is larger than the right pressure receiving area A ₂ , so as soon as the output piston 54 exceeds the step 58, it is moved to the left and slid into contact with the first large diameter portion l ₂ again. It becomes like this. This means that while the gear shift lever L is shifted within the manual gear shift range Mγ, the output piston 54 follows this shift.
This means that you can increase the width and move it left and right. Therefore, by shifting the shift operation lever L left and right in the manual shift range Mγ, the change servo motor CHS and clutch servo motor CLS are activated in the same way as in the automatic drive operation.
It is possible to operate the CVT continuously variable transmission and the clutch mechanism in conjunction with each other.

[] Neutral operation Shift the shift operating lever L beyond the above-mentioned "automatic shift position D" to the left end position shown by the dashed line, that is, the "neutral position N." This position N
Then, the locking ball 65 of the click stopper 61 fits into the notch 64 and locks the speed change operation lever L. In this "neutral position N", the first large diameter portion of the shift operation lever L is in the same position as the "automatic shift position D".
The left end of _l2 fits into the fitting hole 57. On the other hand, the opening/closing special V is now in the open state, and pressure oil from the engine drive pump EP and travel drive pump VP
The pressure oil from the main clutch-off device CLO joins with the pressure oil and passes through the annular groove 67 and the oil supply passage 118.
, the operating lever 110 rotates clockwise and slides the pilot valve 105 of the clutch servo motor CLS to the right regardless of the position of the clutch operating lever 135. Since the servo motor CLS is clutched off, the operating state of the continuously variable transmission CVT is cut off as described above, the rotation of the input shaft 3 is no longer transmitted to the output shaft 15, and the vehicle enters a coasting state.

In addition, pressure oil from the traveling drive pump VP is supplied to the main servo motor with a control valve via the first sub-oil supply path 151.
The servo cylinder 4 passes through the supply oil path 47 of the MS.
8 into the right oil chamber f, and move the output piston 54 to the left end position, that is, the TOP position using the gear shift operation lever L.
slide over the first large diameter part _l2 . As a result, the motor swash plate 11 is tilted to the TOP position (vertical position). That is, when the gear shift lever L is in the neutral position N, the motor swash plate 11 is always
When the shift control lever L is held at the TOP position and then shifted to the drive position, sudden engine braking is not applied, so that shock to the vehicle can be reduced as much as possible.

As described above, according to the present invention, the constant discharge type hydraulic pump connected to the input shaft and the swash plate type variable displacement hydraulic motor connected to the output shaft are communicated via the hydraulic oil distribution mechanism, and the hydraulic oil distribution mechanism includes a distribution board that has suction and discharge ports of the hydraulic pump and a plurality of communication ports of the hydraulic motor opened at one end surface and rotates together with a motor cylinder of the hydraulic motor; a distribution ring forming a high pressure oil chamber communicating between the discharge port and the communication port on the high pressure side, and a low pressure oil chamber communicating between the suction port and the communication port on the low pressure side;
In a hydraulic continuously variable transmission comprising a shutoff device for arbitrarily shutting off the discharge port, the shutoff device is housed in the high pressure oil chamber and closes the discharge port by contacting and separating from the distribution board. The servo motor is arranged in the high pressure oil chamber so as to be able to move forward and backward with respect to the discharge port, and the servo motor is arranged in the high pressure oil chamber so as to be able to move forward and backward with respect to the discharge port. A piston rod whose body is connected so as to be swingable; a front oil chamber integrally formed at the rear of the piston rod and surrounding the piston rod at the front end side and the rear end side; and a rear oil chamber communicating with the high pressure oil chamber. a pilot valve that passes through the rear oil chamber and is slidably engaged with the piston to selectively communicate the front oil chamber with the rear oil chamber and the atmosphere; Since the end pressure receiving area is set to be larger than the pressure receiving area of the piston rod, the valve body can be brought into contact with and separated from the distribution board by a light operation of the pilot valve, and the discharge port can be closed or opened. No matter how inclined the facing surfaces of the distribution panel and the valve body may be due to manufacturing errors, the oscillation of the valve body ensures that they are in close contact with the distribution panel, making it easy to process and assemble the valve body. The performance and quality of the shutoff device can be stabilized without particularly increasing accuracy, which can contribute to cost reduction. Moreover, the working oil pressure of the continuously variable transmission itself can be used as is as the servo oil pressure of the servo motor for driving the valve body.

In particular, since the pressure receiving area at the rear end of the piston is set smaller than the pressure receiving area at the front end of the valve body, the valve body repeatedly comes into contact with and separates from the distribution board in small increments at its valve closing position, so-called "hydraulic floating support". ” condition can be maintained, and as a result, there is no wear on the sliding surfaces between the distribution board and the valve body, which rotate relative to each other,
While minimizing the leakage of hydraulic oil from between the sliding surfaces, it is possible to maintain a good oil-tight state between the sliding surfaces, and thus maintain a reliable direct connection between the hydraulic motor and the hydraulic pump.

[Brief explanation of the drawing]

FIG. 1 is an overall longitudinal sectional view showing essential parts of the device of the present invention, and FIG. 2 is an enlarged sectional view of a clutch servo motor therein. CVT...Continuously variable transmission, CLS...Clutch servo motor as a servo motor, ds...Hydraulic oil distribution mechanism, M...Hydraulic motor, P...Hydraulic pump, 3...Input shaft, 11...Motor tilt Board, 15...
...Output shaft, 17...Distribution panel, 18...Distribution ring, 8
3in...Inner chamber as high pressure oil chamber, 83out...
Outer chamber as a low pressure oil chamber, 84...discharge port,
85...Suction port, 86...Communication port, 92
...Clutch valve as a piston rod, 95...
... Valve body, 96 ... Piston, 97 ... Front oil chamber,
101... Rear oil chamber, 105... Pilot valve,
200...Shutoff device.

Claims (1)

[Claims] 1 A constant discharge hydraulic pump connected to an input shaft and a swash plate type variable displacement hydraulic motor connected to an output shaft are communicated via a hydraulic oil distribution function, and the hydraulic oil distribution mechanism is configured to control suction and discharge of the hydraulic pump. port,
and a distribution board which opens the plurality of communication ports of the hydraulic motor on one end surface and rotates together with the motor cylinder of the hydraulic motor, and a distribution board that contacts one end surface of the distribution board and connects the discharge port and the communication port on the high pressure side. A hydraulic system comprising a communicating high-pressure oil chamber, a distribution ring forming a low-pressure oil chamber communicating between the suction port and the communication port on the low-pressure side, and a shutoff device for arbitrarily shutting off the discharge port. In the continuously variable transmission, the shutoff device includes a valve body housed in the high-pressure oil chamber and capable of closing and opening the discharge port by contacting and separating from the distribution panel;
The servo motor is configured with a servo motor that drives the valve body, and the servo motor is disposed within the high pressure oil chamber so as to be able to move forward and backward with respect to the discharge port, and has a piston rod at its front end that is swingably connected to the valve body. , a piston integrally formed at the rear of the piston rod, and having a front oil chamber surrounding the piston rod and a rear oil chamber communicating with the high pressure oil chamber on the front end side and the rear end side, respectively; a pile rod valve that penetrates the chamber and slides on the piston and can selectively communicate the front oil chamber with the rear oil chamber and the atmosphere; A control device for a hydraulic continuously variable transmission, which is set to be larger than the front end pressure receiving area of the valve body.