JPH01108460A - Direct coupling clutch of hydraulic continuously variable transmission - Google Patents

Abstract

PURPOSE:To minimize the operation lag of a direct connection clutch without bringing a transmission impact by quickly moving the direct connection clutch to the position right before the fully closed position when a transmission ratio of 1 is detected and then smoothly moving the clutch to the fully closed position. CONSTITUTION:When it is detected that the transmission ratio is zero because the angle of inclination of the trunnion of a hydraulic motor M becomes zero, a control circuit 100 changes the duty ratio signal to solenoid valves 151 and 152 and elevates a secondary servo valve 50 quickly to move a direct connection clutch DC to the closed position quickly. Next, the completion of the movement of the clutch to the closed position is detected with a switch 58, the control circuit 100 changes the duty ratio signal and elevates the secondary servo valve 50 slowly to fully close the direct connection clutch DC. Thus, the variation in both thrust of a motor plunger and capacity efficiency of a hydraulic motor can be moderated, the operation lag of the direct clutch minimized, and a transmission impact generated be restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION A.Objective of the Invention (Field of Industrial Application) The present invention relates to a hydraulic continuously variable transmission comprising a constant displacement hydraulic pump and a variable displacement hydraulic motor, and more specifically, This invention relates to a direct coupling clutch device which interrupts a hydraulic closed circuit connecting a pump and a motor to directly connect them when the gear ratio of the transmission is "1".

(Prior art) A constant displacement hydraulic pump is connected to the input shaft, and the oil discharged from this pump is guided through a closed circuit to a variable displacement hydraulic motor, which is driven by a hydraulic motor connected to this. Various continuously variable transmissions that drive the output shaft have been proposed in the past (for example, Japanese Patent Publication No. 32-7159, Japanese Patent Publication No. 5
6-50142, etc.).

In such a device, a direct coupling clutch device that can connect and disconnect the hydraulic closed circuit is provided, so that the angle of the swash plate that variably controls the capacity of the hydraulic motor is minimized, and the gear ratio of the transmission is set to “1”.
It is known to use this direct coupling clutch device to cut off the hydraulic closed circuit and rotate the pump and motor together when the condition becomes .

As a control method for a continuously variable transmission having this direct coupling clutch device, for example, as disclosed in Japanese Patent Application Laid-Open No. 54-134252, Japanese Patent Application Laid-Open No. 55-14312, etc.,
The engine speed matches the target speed according to the throttle opening, and the gear ratio is controlled to obtain the minimum fuel consumption rate. When the gear ratio reaches the minimum, that is, "1", the direct clutch device closes the engine. There is a method of cutting off the circuit and rotating the pump and motor together.

(KM while the invention is trying to solve the problem) However, when controlling the direct coupling clutch as described above, even if the gear ratio is "1", the closed circuit is not interrupted by the direct coupling clutch. Due to the difference in the presence or absence of hydraulic thrust acting on the motor plunger and the difference in volumetric efficiency, there is a difference in the pump drive load by the engine between when the motor plunger is closed and when it is shut off, so the direct coupling clutch is activated to shut off the closed circuit. There is a problem in that when driving, the engine speed drops and driving shock occurs, impairing the driving feeling.

For example, as disclosed in Japanese Patent Application Laid-open No. 55-1-290, when starting the operation of the direct coupling clutch after the gear ratio becomes the minimum, the closed circuit 31 ! There is a problem in that an operation delay occurs due to the time it takes for the disconnection to be completed.

In view of the above problems, the present invention provides a direct coupling clutch device that can quickly and smoothly interrupt a hydraulic closed circuit when the swash plate angle of the hydraulic motor becomes the minimum and the gear ratio becomes "1". The purpose is to provide

B6 Structure of the Invention (Means for Solving the Problem) As a means for achieving this object, the direct-coupled clutch device of the present invention includes a direct-coupled clutch valve that can connect and disconnect a hydraulic closed circuit, a direct-coupled clutch actuator mechanism for actuating the same, and a direct-coupled clutch actuator mechanism that operates the same. Minimum gear ratio detection means for detecting that the gear ratio of the gear transmission has become 1", and immediate position detection means for detecting that the direct coupling clutch valve is at a position just before it has moved from the fully closed position to the open side by a predetermined amount. When the direct coupling clutch valve is in the fully open position, when it is detected that the gear ratio has become "1", the direct coupling clutch valve is rapidly moved from the fully open position to the immediately preceding position, and the direct coupling clutch valve is in the fully open position. When the clutch valve moves to the immediately preceding position, the direct coupling clutch valve is slowly moved from the immediately preceding position to the fully closed position.

(Function) When the direct coupling clutch device with the above configuration is used, for example, the gear ratio is controlled so that the engine rotation matches the target rotation speed according to the throttle opening, and the gear ratio becomes 1'''. When is detected, the actuator mechanism is activated and the direct coupling clutch valve is rapidly moved from the fully open position to the immediately preceding position, thereby reducing the delay in operation of this direct coupling clutch mechanism.The direct coupling clutch valve is moved to the immediately preceding position. Then, in response to a signal from the immediately preceding position detecting means that detects this, the actuator mechanism smoothly moves the direct coupling clutch valve from the immediately preceding position to the fully closed position.As a result, the closing of the closed circuit is gradually interrupted. This cuts off the thrust to the motor plunger and alleviates the running shock caused by the improvement in volumetric efficiency.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 is a hydraulic circuit diagram of a continuously variable transmission having a direct coupling clutch device according to the present invention. type swash plate axial plunger type hydraulic pump P,
It has a variable capacity swash plate axial plunger type hydraulic motor M that drives the wheels W via a forward/reverse switching device 20. These hydraulic pump P and hydraulic motor M are connected to a first
The two oil passages, the oil passage La and the second oil passage Lb which communicates the suction port of the pump P and the discharge port of the motor M, are connected to form a hydraulic closed circuit. Of these two oil passages La and Lb, the first oil passage La is connected to a pump P driven by the engine E, and the oil pressure from the pump P is used to drive the motor M.
is rotationally driven to drive the wheels W, that is, when the wheels W are driven by the engine E via the continuously variable transmission T, the pressure becomes high (at this time, the second oil passage Lb
On the other hand, the second oil passage Lb has a high pressure when the engine brake is applied by receiving the driving force from the wheels W, such as when the vehicle is decelerating (at this time, the second oil passage Lb has a low pressure). La is low pressure).

Furthermore, a direct coupling clutch valve DC that can connect and disconnect this oil passage La is disposed within the first oil passage La.

In addition, a charge pump 10 driven by the engine E
A charge oil passage L whose discharge port has a check valve 11
h and a third oil passage Lc having a pair of check valves 3.3, the hydraulic oil is pumped up from the oil sump 15 by the charge pump 10 and pressure regulated by the charge pressure relief valve 12. Due to the action of the check valve 3.3, the two oil passages La and Lb are
The oil is supplied to the low pressure side oil passage. Additionally, the oil sump 15 has high and low pressure relief valves 6.7.
A fourth oil path Ld having a shuttle valve 4 connected to fifth and sixth wave paths Le and Lf connected to the closed circuit is connected to the closed circuit. This shuttle valve 4 is a two-bottom, three-position switching valve that operates according to the oil pressure difference between the first and second oil passages La and Lb, and is operated on the higher pressure side of the first and second oil passages La and Lb. The oil passage on the low pressure side is made to communicate with the fifth oil passage Le, and the oil passage on the low pressure side is made to communicate with the sixth oil passage Lf. As a result, the relief oil pressure in the oil passage on the high pressure side is regulated by the high pressure relief valve 6, and the relief oil pressure in the oil passage on the low pressure side is regulated by the low pressure relief valve 7.

Furthermore, a seventh oil passage Lg is provided between the first and second oil passages La and Lb to short-circuit both oil passages. A main clutch valve CL consisting of a variable throttle valve is provided.

The output shaft 28 connected to the wheel W is arranged parallel to the drive shaft 2 of the hydraulic motor 4, and a forward/reverse switching device 20 is provided between both shafts 2°28. This device 20 includes first and second drive gears 21 and 22 arranged on the drive shaft 2 with an interval in the axial direction, rotatably supported by an output shaft 28 and meshed with the first drive gear 21. a first driven gear 23 that meshes with the second drive gear 22 via an intermediate gear 24 and is rotatably supported on the output shaft 28, and first and second wave gears 23, 25. A clutch hub 26 is fixed to the output shaft 28 between the clutch hub 26 and the driven gears 23, 25, which are slidable in the axial direction.
A sleeve 27 selectively connects the clutch gear 23a or 25a formed on the side surface of the clutch gear 23a or 25a, respectively.
This sleeve 27 is moved left and right by a shift fork 29. In this forward/reverse switching device 20, the sleeve 27 is slid leftward in the figure by the shift fork 29, and the clutch gear 23a of the first driven gear 23 is shifted as shown in the figure.
In a state where the clutch hub 26 and the clutch hub 26 are connected, the output shaft 28 is rotated in the opposite direction to the drive shaft 2, and the wheels W are rotated in the forward direction as the continuously variable transmission T is driven. On the other hand, the sleeve 27 is slid to the right by the shift fork 29, and the clutch gear 25a of the second driven gear 25 and the clutch hub 2
6, the output shaft 28 is connected to the drive shaft 2.
, and the wheels W are rotated in the reverse direction.

An actuator that controls the capacity of the hydraulic motor M to control the gear ratio of the continuously variable transmission T and controls the operation of the direct clutch valve DC is connected to first and second servos connected by a link mechanism 40. The valve is 30.50.

The operations of the first and second servo valves 30, 50 are controlled by respective pairs of solenoid valves 151, 152 whose duty ratios are controlled in response to signals from the controller 100. This controller 100 includes vehicle speed V,
Signals indicating engine speed Ne, throttle opening θth, swash plate inclination angle θtr of hydraulic motor M, shift lever position Psl manually operated by the driver, opening θc1 of main clutch valve DC, etc. are input. , and based on these signals, signals are outputted to control each solenoid valve so as to obtain desired travel.

FIG. 2 is a sectional view showing the specific structure of the continuously variable transmission, and this transmission T includes cases 5a, 5b and a cover 50.
A hydraulic pump P and a hydraulic motor M are installed in a space surrounded by
are arranged concentrically.

The hydraulic pump P includes a pump cylinder 60 spline-coupled to the input shaft 1, and a pump cylinder 60 connected to the input shaft 1.
It consists of a plurality of cylinder holes 61 provided at equal intervals on the circumference so as to surround the input shaft 1 in parallel with the input shaft 1, and a plurality of pump plungers 62 that are slidably engaged with the cylinder holes 61, respectively. It is rotationally driven by the power of the engine E transmitted via the wheel FW.

The hydraulic motor M includes a motor cylinder 70 provided surrounding the pump cylinder 60, and the motor cylinder 70,
It is composed of a plurality of cylinder holes 71 that are provided at equal intervals on the circumference in parallel with the input shaft 1 and surrounding the input shaft 1 and the pump cylinder 60, and a plurality of motor plungers 72 that are slidably engaged with the cylinder holes 71, respectively. The pump cylinder 60 can be relatively rotated coaxially with the pump cylinder 60.

A pair of support shafts 7 are provided at both ends of the motor cylinder 70 in the axial direction.
8a, 78b are provided protrudingly, and both support shafts 78a, 78b
is rotatably supported by the cases 5a and 5b via a needle bearing 79a and a ball bearing 79b. In addition,
The support shaft 78a constitutes the output shaft 2 of the motor M, and the support shaft 78a (output shaft 2) is connected to the forward/reverse switching device 2.
0 first and second drive gears 21,22 are attached in a splined manner.

A pump swash plate 6 is provided on the left inner side of the motor cylinder 70 and is inclined at a predetermined angle with respect to each pump plunger 62.
3 is fixed, and an annular pump shoe 64 is rotatably supported on the inclined surface thereof. Each pump plunger 62 and pump shoe 64 are connected to each other so as to be able to swing to some extent through a connecting rod 65 having ball joints at both ends.

The annular pump shoe 64 has its outer peripheral surface supported inside the motor cylinder 70 via a needle bearing 66, and the pump shoe 64 is supported by a presser ring 67a.
The pump shoe 64 is pressed against the pump swash plate 63 by a spring 67c via a spring holder 67b in spherical contact with the pump shoe 64. In this way, the pump shoe 64 can always rotate and slide in a fixed position on the pump swash plate 63. can.

Bevel gears 68a and 68b, which mesh with each other and have the same number of teeth, are fixed to opposing end surfaces of the pump cylinder 60 and the pump shoe 64, respectively. By meshing these bevel gears 68a and 68b, when the pump cylinder 60 is driven from the input shaft 1, the pump cylinder 60 rotationally drives the pump shoe 64. Along with these rotations, the pump plunger 62 running on the upward side of the inclined surface of the pump swash plate 63 is given a discharge stroke from the pump swash plate 63 via the pump shoe 64 and the connecting rod 65.
Also, the pump plunger 62 running on the down side of the slope is given a suction stroke.

Case 5. Inside a and 5b, each motor plunger 7
A motor trunnion 73 facing the motor trunnion 73 is tiltably supported via a pair of trunnion shafts 73a protruding from both outsides thereof in a direction perpendicular to the paper surface of FIG. Arranged motor swash plate 73
A motor shoe 74 that slides into contact with b is swingably connected to a ball joint 72a formed at the outer end of each motor plunger 72.

Each motor plunger 72 performs reciprocating motion similarly to the pump plunger 62 described above, and rotates the motor cylinder 70 while repeating expansion and contraction strokes. At this time, the stroke of the motor plunger 72 is changed by changing the inclination angle of the motor trunnion 73 from a vertical position perpendicular to each motor plunger 72 to the maximum inclination position shown in the figure as described below. Adjustable steplessly from 0 to maximum.

The motor cylinder 70 has a first cylinder divided in its axial direction.
- Consisting of fourth portions 70a to 70d. 1st
The above-mentioned support shaft 78a is formed in the portion 70a, and a pump swash plate 63 is provided on the inner surface thereof, and the second portion 70b has a cylinder hole for guiding the sliding movement of the motor plunger 72. 71 is formed, the third portion 70c has a distribution plate 80 in which oil passages to each cylinder hole 61.71 are formed, and the fourth portion 70d has a negative support shaft 78b formed therein. ing. These first to fourth parts 7
0a to 70d are positioned by fitting or knock pins, and are integrally connected by a plurality of bolts 77a and 77b.

The pump cylinder 60 is pressed against the distribution board 80, which is the third portion 70c, by the elastic force of the spring 67c, and is designed to prevent oil from leaking from these rotating sliding parts. .

The fourth portion 70d of the motor cylinder 70 having one of the support shafts 78b is formed hollow, and has a hole in its center.
A fixed shaft 91 is inserted. A distribution ring 92 is fluid-tightly fitted to the left end of the fixed shaft 91 via an O-ring, and the left end surface of the distribution ring 92 in the axial direction is eccentric and the distribution plate 8
It is designed so that it can come into sliding contact with 0. This distribution ring 92 divides the hollow portion formed in the fourth portion 70d of the motor cylinder 70 into an inner oil chamber and an outer oil chamber, with the inner oil chamber forming the first oil passage La and the outer oil chamber forming the first oil passage La. The oil chamber is the second oil path Lb
Configure.

A pump discharge boat 81a and a pump suction boat 82a are bored in the distribution board 80, and the discharge boat 8
1a and the discharge passage 81b connected thereto, the cylinder hole 61 of the pump plunger 62 in the discharge stroke and the first oil passage La consisting of an inner oil chamber are communicated, and the suction boat 82a and the suction passage connected thereto are communicated with each other. via 82b,
Cylinder hole 61 of pump plunger 62 during suction stroke
and a second oil passage Lb consisting of an outer oil chamber are communicated with each other.

Further, the distribution board 80 includes a first communication passage (not shown) that communicates the cylinder hole 71 of the motor plunger 72 in the expansion stroke with the first oil passage La, and a cylinder hole of the motor plunger 72 in the contraction stroke. A second communication path 83 is formed that communicates the second oil path Lb with the second oil path Lb.

In this way, a hydraulic closed circuit is formed between the hydraulic pump P and the hydraulic motor M via the distribution panel 80 and the distribution ring 92. Therefore, when the pump cylinder 60 is driven from the input shaft 1, the high pressure hydraulic oil generated by the discharge stroke of the pump plunger 62 is transferred to the discharge boat 81a.
The oil flows from the discharge passage 81b, the first oil passage La (inner oil chamber), and the first communication passage (not shown) communicating therewith into the cylinder hole 71 of the motor plunger 72 in the expansion stroke. A thrust is given to the motor plunger 72. On the other hand, the hydraulic oil discharged by the motor plunger 72 which is in the contraction stroke is in the suction stroke via the second communication passage 80 communicating with the second oil passage Lb (outer oil chamber), the suction passage 82b and the suction boat 82a. It flows into the cylinder hole 61 of the pump plunger 62. Due to such circulation of the hydraulic oil, the pump plunger 62 in the discharge stroke moves to the pump trunnion 63.
The reaction torque applied to the motor cylinder 70 via the expansion stroke motor plunger 72 is applied to the motor trunnion 73.
The motor cylinder 70 is rotationally driven by the sum of the reaction torque received from the motor cylinder 70 .

In this case, the gear ratio of the motor cylinder 70 to the pump cylinder 60 is given by the following equation.

Number of revolutions of pump cylinder 60 Capacity of hydraulic motor M = 1+ □ Capacity of hydraulic pump PAs can be seen from the above formula, if the capacity of hydraulic motor M is changed from O to a certain value, the gear ratio can be changed from 1 (minimum value). It can be changed up to a certain required value (maximum value).

By the way, the capacity of the hydraulic motor M is the motor plunger 7.
2, the gear ratio can be adjusted steplessly from 1 to a certain value by tilting the motor trunnion 73 from the upright position to a certain inclination angle as described above.

The first and second servo valves 30.50 control the tilting angle of the motor trunnion 73. It is connected to the first servo valve 30 via 40. These are shown in FIG. 3, and the structure and operation of these servo valves 30.degree. 50 will be explained using this drawing as well.

The first servo valve 30 has a connection port 31a to which a high pressure line 120 for introducing high pressure hydraulic oil led from the closed circuit of the continuously variable transmission T to the fifth oil path Le via the shuttle valve 4 is connected. A piston member 32 is fitted into the housing 31 so as to be slidable left and right in the drawing, and a spool member 34 is fitted into the piston member 32 so as to be slidable left and right. It has the following. The piston member 32 includes a piston portion 32a formed at the right end portion, and a cylindrical rod portion 32b that is attached to the piston portion 32a and extends to the left from the piston portion 32a.The piston portion 32a is formed within the housing 31. The rod portion 32b is fitted into the cylinder hole 31c to divide the inside of the cylinder hole 31c into two to form left and right cylinder chambers 35, 36, and the rod portion 32b has a smaller diameter than the cylinder hole 31c and is fitted into the same rod hole 31d. inserted. Note that the right cylinder chamber 35 is closed by a plug member 33a and a cover 33b, and the spool member 34 is disposed passing through these.

A high pressure line 120 connected to the connection port 31a is connected to the left cylinder chamber 35 partitioned by the piston portion 32a through an oil passage 31b, and the piston member 32 is introduced into the left cylinder chamber 35. high pressure line 1
It receives a pushing force in the right direction in the figure by the hydraulic pressure from 20.

A land portion 34a is formed at the tip of the spool member 34 so as to fit closely into the spool hole 32d, and two diagonal surfaces on the right side of the land portion 34a are formed in a predetermined axial direction. The dimensions are shaved off to form a recess 34b. A retaining ring 37 is fitted into the right side of this recess 34b, and is prevented from being removed by coming into contact with a retaining ring 38 fitted to the inner peripheral surface of the piston member 32.

The piston member 32 has a discharge passage 32e that can open the right cylinder chamber 35 to an oil sump (not shown) via the spool hole 32d in response to rightward movement of the spool member 34.
According to the leftward movement of the spool member 34, the recess 34b
A communication path 32C is bored through which the right cylinder chamber 35 can be communicated with the left cylinder chamber 36.

When the spool member 34 is moved to the right from this state, the land portion 34a closes the communication path 32c and opens the discharge path 32e. Therefore, the pressure oil from the high pressure line 120 flowing in through the oil passage 31b acts only on the left cylinder chamber 35, and moves the piston member 32 to the right to follow the spool member 34.

Next, when the spool member 34 is moved to the left, the concave portion 34b connects the communication path 32c to the right cylinder chamber 36, contrary to the above, and the land portion 34a closes the discharge path 32e. Therefore, the high pressure oil acts on both the left and right cylinder chambers 35 and 36, but due to the difference in pressure receiving area, the piston member 32
is moved to the left so as to follow the spool member 34.

Further, when the spool member 32 is stopped midway, the piston member 32 is placed in a hydraulic floating state due to the pressure balance between the left and right cylinder chambers 35, 36, and stops at that position.

In this way, by moving the spool member 34 from side to side, the piston member 32 can be moved to follow the spool member 34 using the hydraulic pressure of the high-pressure hydraulic oil from the high-pressure line 120, and thereby the link The displacement of the swash plate 73 of the hydraulic motor M connected to the piston member 32 via the piston member 39 can be variably controlled by rotating the swash plate 73 about its rotation shaft 73a.

The spool member 34 is connected to a second speed change servo valve 50 via a link mechanism 40. This link mechanism 4
0 includes a first link member 42 having two substantially right-angled arms 42a and 42b that are rotatable about a shaft 42c, and a first link member 42 that is pin-coupled to the tip of the arm 42b of the first link member 42. 2 link members 48, and the arm 4
The upper end of the second link member 48 is pin-coupled to the right end of the spool member 34 of the first shift servo valve 30, and the lower end of the second link member 48 is connected to the second shift servo valve 50.
It is pin-coupled to the spool member 54 of. For this reason,
When the spool member 54 of the second shift servo valve 50 moves up and down, the spool member 34 of the first shift servo valve 30 is moved left and right.

The second servo valve 50 has two hydraulic lines 102.1
A housing 51 having boats 51a and 51b to which the 04 is connected, and a spool member 54 fitted into the housing 51 so as to be slidable up and down in the figure. Piston part 54
It consists of a rod portion 54b extending downwardly and co-extensive with this. The piston portion 54a is fitted into a cylinder hole 51c formed in the housing 51 to extend vertically, and divides the cylinder chamber surrounded by the cover 55 into upper and lower cylinder chambers 52 and 53. The rod portion 54b is fitted into a rod hole 51d that extends downward and is the same as the cylinder hole 51c.

Note that the rod portion 54b has a concave portion 54e having a tapered surface.
A spool 58a of the immediate position determination switch 58 protrudes into the recess 54e, and when the spool 58a is pushed up along the tapered surface at a position near the end of the upward movement of the spool member 54, the hydraulic motor M After the gear ratio becomes the minimum, it is possible to detect whether the direct coupling clutch valve DC, which will be described later, is located at the immediately preceding position.

Additionally, hydraulic lines 102 and 104 are connected to the boats 51a and 51, respectively, to the upper and lower cylinder chambers 52 and 53, which are divided into two by the piston portion 54a.
b, and both hydraulic lines 102, 104
Hydraulic oil pressure and both cylinder chambers 5 supplied through
The spool member 54 is moved up and down in accordance with the magnitude of the hydraulic pressure applied to the piston portion 54a, which is determined by the pressure-receiving area of the piston portion 54a that receives the hydraulic pressure within 2.53.

This vertical movement of the spool member 54 is transmitted to the spool member 34 of the first shift servo valve 30 via the link mechanism 40, causing it to move horizontally. That is, by controlling the hydraulic pressure supplied via the hydraulic lines 102 and 104, the movement of the spool member 34 of the first servo valve 30 is controlled, which in turn moves the piston member 32 to control the swash plate angle of the hydraulic motor M. Specifically, by moving the spool member 54 of the second servo valve 50 upward, the piston member 32 of the first servo valve 30 is moved to the right. By doing so, the swash plate angle can be made small, the capacity of the hydraulic motor M can be made small, and the gear ratio can be made small.

The hydraulic pressure of the hydraulic line 102 is as shown in FIG.
Hydraulic oil whose pressure is regulated by the charge pressure relief valve 12 from the discharge oil of the charge pump 10 is supplied to the hydraulic lines 101 and 1.
02, and the hydraulic pressure in the hydraulic line 104 is introduced through the orifice 10 branched from the hydraulic line 102.
This is the oil pressure obtained by controlling the oil pressure of the oil pressure line 103 having 3a with two solenoid valves 151 and 152 whose duty ratio is controlled. Solenoid valve 15
Reference numeral 1,152 is driven and controlled by signals from the controller 100, and as can be seen from this, signals from the controller 100 control the operation of the first and second servo valves 30, 50, and the hydraulic motor. The capacity of M is controlled.

Next, the main clutch CL and the direct coupling clutch DC will be explained with reference to FIG. 4. FIG. 4 is a diagram showing in detail the main clutch CL and direct coupling clutch DC disposed within the fixed shaft 91 inserted into the hollow portion within the fourth portion 70d of the motor cylinder 70.

A cylindrical bearing member 93 is coupled to the outer peripheral surface of the fixed shaft 91, and the motor cylinder 70 (fourth portion 70d) can rotate relative to the fixed shaft 91 by this bearing member 93. .

A first oil passage L, which is an inner oil chamber, is provided on the peripheral wall of the hollow fixed shaft 91.
Short-circuit boats 91a and 91b are bored through which the oil passage Lb and the second oil passage Lb, which is an outer oil chamber, can communicate with each other. A cylindrical main clutch valve body 95 is fitted into a hollow portion of the fixed shaft 91 in order to open and close the boats 91a and 91b.

The main clutch valve body 95 is assembled so that it can be freely rotated relative to the fixed shaft 91 after being positioned in the radial and axial directions with respect to the fixed shaft 91 by a radial needle bearing 96a and a thrust needle bearing 96b. Short-circuit holes 95 are provided on the peripheral wall at the left end of the fixed shaft 91 and can be aligned with the short-circuit boats 91a and 91b of the fixed shaft 91, respectively.
a.

95b is bored, and a rotation link 97 is coupled to the right end. By rotating this rotation link 97, the main clutch valve body 95 is rotated and the short circuit hole 9 is rotated.
The relative positions of 5a, 95b and the shorting boats 91a, 91b can be changed. Therefore, due to this rotation, when the shorting boats 91a, 91b are fully opened, the clutch is turned off, and when the shorting holes 95a, 95b are shifted to half open the shorting boats 91a, 91b, the clutch is turned half-clutched. When the short-circuit boats 91a and 91b are fully closed, the clutch ON state can be obtained, and the main clutch valve DC is configured in this way. Here, in the illustrated crack-off state, the hydraulic oil discharged from the discharge boat 81a to the first oil passage La is directly transferred from the second oil passage Lb to the suction boat 82a via the short-circuit boats 91a and 91b. Hydraulic motor M
When the clutch is inactive and the clutch is in the ON state, the above-mentioned short-circuit flow of the hydraulic oil is prevented, a circulation action is performed from the hydraulic pump P to the hydraulic motor M, and normal power transmission is performed. However, this main clutch valve body 95 is ON/
A description of the rotation operating device for the rotation link 97 for turning off will be omitted.

A direct coupling clutch valve DC is provided in the center of the hollow main clutch valve body 95. A piston shaft 85 of this direct coupling clutch valve DC is slidably engaged with a hollow hole of a main clutch valve body 95, and a valve rod 86a is screwed onto the tip of this piston shaft 85. Valve rod 86
The tip of a is formed into a partially spherical surface, and a shoe 86b is connected thereto so as to be swingable.

When the piston shaft 85 moves to the left in FIG.
The open end of the discharge passage 81b connected to 1a is opened in a liquid-tight manner to block the flow of hydraulic oil from the discharge boat 81a to the first oil passage La (inner oil chamber). In this shut-off state, the pump plunger 62 is hydraulically locked, and the hydraulic pump P and the hydraulic motor M are directly connected, and the pump plunger 62 is connected from the pump cylinder 60 to the pump plunger 62.
and the motor cylinder 70 via the pump swash plate 63.
will be mechanically driven. This direct connection between the hydraulic pump P and the hydraulic motor M is performed at the minimum gear ratio position with the motor trunnion 73 upright, that is, at the top position, which improves the efficiency of power transmission from the input shaft to the output shaft. At the same time, it is possible to reduce the thrust exerted by the motor plunger 72 on the motor trunnion 73, thereby reducing frictional resistance and reducing the load on each member such as a bearing.

The right side of the piston shaft 85 is stepped and reduced in diameter, and forms an oil chamber 87a between it and an inner member 96c of a thrust needle bearing 96b that supports the main clutch valve body 95. This oil chamber 87a is normally located at the piston shaft 8.
The first oil passage La
is connected to. When the engine is driven, a portion of the high-pressure hydraulic oil circulating between the hydraulic pump P and the hydraulic motor M is constantly supplied to the oil chamber 87a through the series of passages.

A piston portion 85 is provided at an axially intermediate portion of the piston shaft 85.
a is integrally formed, and an annular chamber 87b is formed between the inner surface of the hollow hole of the main clutch valve body 95 and the outer peripheral surface of the piston shaft 85 on the left side of the piston portion 85a. Furthermore, a dead end hole 88 is bored in the center of the piston shaft 85, and extends beyond the piston part 85a from the right end surface.
is formed. A through hole 8 bored in the piston shaft 85 in the radial direction is located between the blind hole 88 and the annular chamber 87b.
9c. Further, a through hole 89d is provided near the right end surface of the piston portion 85a to allow communication between the through hole 89a and the dead hole 88.

A rod-shaped pilot valve 84 is inserted into the blind hole 88 . A land portion 84a that fits into the inner peripheral surface of the dead-end hole 88 is formed at the tip of the pilot valve 84,
A small diameter portion 84b is formed on the right side of the land portion 84a and has an appropriate axial dimension. Furthermore, an atmosphere communication hole 89e is bored in the center of the pilot valve 84 to communicate the interior of the dead-end hole 88 with the atmosphere. The pilot valve 84 slides in the left-right direction by a link arm 46 that is engaged at its outermost end.

The operation of this link arm 46 will be described later.

In the above configuration, the dimensions of each part are as shown in the shoe 86.
Pressure-receiving area of end face of b: Cross-sectional area of A piston portion 85a : Pressure-receiving area of inner end side of B piston shaft 85
:C The cross-sectional area of the reduced diameter portion of the piston shaft 85 is determined so that the inequality A>(B-D>(B-D)>C is satisfied).

When the pilot valve 84 is moved to the left, the small diameter portion 84b of the pilot valve 84 is completely fitted into the dead end hole 88 inward from the right end surface of the piston portion 85a.
The through hole 89d is closed by the outer peripheral surface of the pilot valve 84,
The high pressure hydraulic oil from the discharge boat 81a flows through the oil passage 89a.
, 89b, and flows into the oil chamber 87a, and the oil pressure acts on the right end surface of the piston portion 85a, and also flows into the first oil passage La.
It also acts on the left end surface of the piston shaft 85 from the side.

At this time, the pressure receiving area of the right end surface of the piston portion 85a is (B-
D), and since the pressure receiving area of the inner end surface of the piston shaft 85 is C, the piston shaft 85 will move to the left based on the relationship of inequality (B-D)>C. As the piston shaft 85 moves, the shoe 86b comes into contact with the end surface of the discharge passage 81b communicating with the discharge boat 81a of the distribution board 80 and closes it, thereby realizing a direct connection between the hydraulic pump P and the hydraulic motor M.

In this state, high-pressure hydraulic oil from the discharge boat 81a (equal pressure to the oil pressure in the oil chamber 87a) acts on the end surface of the shoe 86b having the pressure-receiving area A, while the piston portion 86b
There is an oil chamber 87 on the right end surface with a pressure receiving area (B-D) of 5a.
The high-pressure hydraulic oil in a acts on it. By the way, since the two receiving areas are in the relationship of the inequality A>(B-D),
A force is applied to the shoe 86b to move it to the right.

If the shoe 86b moves to the right even slightly, the hydraulic pressure on the end surface of the shoe 86b is released, and the shoe 86b is moved again to the distribution board 8.
It is pressed against the end face of 0.

In this way, by setting each pressure receiving area of A, B, and C to a predetermined value so as to satisfy the above-mentioned inequality, a so-called hydraulic floating state can be maintained, and the connection between the shoe 86b and the discharge passage 81b can be maintained. It is possible to maintain a good oil-tight state between these while minimizing the leakage of hydraulic oil between them.

Next, when the pilot valve 84 is moved to the right, the small diameter portion 84b of the pilot valve 84 communicates with the through hole 89d formed in the piston shaft 85. As a result, high-pressure hydraulic oil is simultaneously applied to the right end surface of the piston portion 85a and the piston shaft 85a.
In addition to acting on the left end surface of the through hole 89d, the small diameter portion 84b,
The piston portion 8 passes through the communication hole 89C and the annular chamber 87b.
It also acts on the left end surface of 5a. At this time, the pressure receiving area for moving the piston shaft 85 to the left is (B-D), while the pressure receiving area for moving the piston shaft 85 to the right is B, and B>(B-D). Therefore, the piston shaft 85 moves to the right, and the direct connection between the hydraulic motor M and the hydraulic pump P is released.
When the pilot valve 84 is moved in the left-right direction, the piston shaft 85 is also moved in the left-right direction following this movement, and the direct coupling clutch valve DC is turned on and off.

This movement of the pilot valve 84 in the left-right direction is performed by the operation of the second servo valve 50 transmitted through the link mechanism 40 described above. Therefore, this link mechanism 40 will be explained.

FIG. 5 shows this link mechanism 40, which connects the first and second servo valves 30 as described above.
．． Two arms 42a and 42b connect the first servo valve 30 through a pin.
The first shaft 42c has a first shaft 42c (the arm 42b is connected to the spool member 54 of the second servo valve 0 through a second link 48), and It has a second shaft 45 arranged in parallel with this, and both shafts 42c, 4
5 denotes bearings 49a, 49b, 49 fixed to the case 5a.
It is rotatably supported by c.

As mentioned above, the pilot valve 84 of the direct coupling clutch valve DC
The rotation link 46 connected to the second shaft 45
The rotary link 46 is rotated as the second shaft 45 rotates, and the pilot valve 84 is moved left and right to turn the direct coupling clutch valve DC ON-OFF. Note that the rotation link 46 is always biased by a torsion coil spring 46a wound around the second shaft 45 so as to draw the pilot valve 84 outward (to the right).

On the other hand, driving and driven cams 43 and 44 that mesh with each other are fixedly installed on the first and second shafts 42c and 45, and the action of these cams 43 and 44 corresponds to the rotation of the first shaft 42c. 2 shaft 45 is given a certain degree of rotation.

The operation of the cams 43, 44 will be explained based on FIGS. 6A to 6C. As shown in these figures, the drive cam 43 includes a semicircular portion 43a that has a semicircular arc centered on the first shaft 42c, and a convex portion that partially protrudes outward from the radius of the semicircular portion 43a. It consists of a portion 43b and a recessed portion 43c that is partially recessed inward from the radius of the semicircular portion 43a, and is formed into a contour that smoothly connects these three portions. On the other hand, the driven cam 44 includes a semicircular portion 43a, an arcuate portion 44a consisting of a concave surface with a curvature such as time, and the arcuate portion 44a.
It consists of a straight portion 44b extending generally in the direction of the close battle.

First, as shown in FIG. 2, when the spool member 54 of the second servo valve 50 moves to the lowest position and the inclination of the trunnion 73 of the hydraulic motor M becomes the maximum (at this time, the gear ratio is maximum), , as shown in FIG. 6A, the drive cam 43
The semicircular portion 43 a of the driven cam 44 contacts the arcuate portion 44 a of the driven cam 44 , and the convex portion 43 b of the driving cam 43 and the straight portion 4 of the driven cam 44 contact each other.
It is far from 4b. Therefore, the rotation link 46 moves the pilot valve 84 to the right under the biasing force of the torsion coil spring 46a, and the direct coupling clutch valve DC is in a fully open state. In this state, the spool member 5 of the second servo valve 50
The lower end of 4 is located at the (mouth) position in FIG. When the spool member 54 moves down to the lowest position, it is located at the position (A), which absorbs the play of the link mechanism 40 and improves the responsiveness of the motor trunnion 73 to the operation of the second servo valve 50. In order to increase the height, the spool member 54 is positioned at the (opening) position, which is slightly moved upward from the (a) position.

From the above state, when the spool member 54 of the second servo valve 50 is moved upward in order to reduce the inclination angle of the motor trunnion 73, the first shaft 42c is rotated clockwise and the first servo valve 30 rotates the motor trunnion. 73
is rotated clockwise around the trunnion shaft 73a, its inclination angle becomes smaller, and the gear ratio becomes smaller. At this time, the drive cam 43 rotates as the first shaft 42c rotates.
Although the driven cam 44 is also rotated, the straight portion 4 of the driven cam 44
The driven cam 4b is not rotated until the convex portion 43b of the driven cam 43 comes into contact with it, and therefore the pilot valve 84 is not moved, and the direct coupling clutch valve DC is kept fully open.

When the spool member 54 of the second servo valve 50 is further moved upward, the motor trunnion 73 becomes upright, and the gear ratio becomes 1'' (minimum), as shown in FIG. The convex portion 43b of the driving cam 43 rotated clockwise is connected to the straight portion 44b of the driven cam 44.
comes into contact with. At this time, the lower end of the spool member 54 of the second servo valve 50 is at the position shown by (c) in FIG. The fact that the motor trunnion 73 is in the upright state and the gear ratio is at its minimum is detected by a potentiometer (not shown) attached to the motor trunnion 73, and this detection signal is sent to the controller 100.
is input.

From the above state, the spool member 5 of the second servo valve 50
4 is further moved upward, the first shaft 42c is further rotated clockwise, and the spool member 34 of the first servo valve 30 is further moved to the right, but the motor trunnion 73 is prevented from moving further by the stopper. It is prevented from rotating and held in an upright position. However, the first shaft 42c
is rotated, the drive cam 43 is rotated clockwise, and as a result, the straight portion 44b is pushed by the convex portion 43b of the drive cam 43, and the driven cam 44 is rotated clockwise. rotated in the direction.

When the driven cam 44 is rotated clockwise in this manner, the second shaft 45 and the rotation link 46 are also rotated against the biasing force of the torsion coil spring 46a, and as a result, the pilot valve 84 is rotated to the left. being pushed towards As a result, the piston shaft 85 is moved to the left as described above, and the shoe 86b closes the discharge passage 81b and is in the direct connection state (the direct connection clutch valve DC is ON).
state) is realized.

However, when moving the pilot valve 84 to the left to bring the direct coupling clutch valve DC into the direct coupling state as described above, if the moving speed of the pilot valve 84 is slow, the motor trunnion 73 will be in the upright state and the pilot valve 84 will be in the upright state. The time from the start of movement until the shoe 86b closes the discharge path 81b becomes long, which may cause a delay in operation. However, if the moving speed is increased, the hydraulic thrust to the motor plunger 72 will decrease due to the discharge passage 81b being blocked by the shoe 86b, and the engine load will fluctuate rapidly due to the improvement in volumetric efficiency, resulting in shift shock. may occur and the driving feeling may be impaired.

Therefore, in the continuously variable transmission T shown in this embodiment, the movement of the pilot valve 84 causes the shoe 86b to move toward the discharge path 81.
The immediate position determination switch 58 attached to the second servo valve 50 determines that the shoe 86b is at a position slightly open to the open side from the fully open position, that is, the position immediately before the shoe 86b completely closes the discharge passage 81b. In this state, the lower end of the spool member 54 of the second servo valve 50 is in the state shown in (2) in FIG. 2), and the moving speed of the pilot valve 84 is made to be different before and after the immediately preceding position. .

Specifically, a potentiometer that detects the inclination angle of the motor trunnion 73 detects that this inclination angle becomes 0 and the gear ratio becomes 1 (the lower end of the spool member 54 is at the position (c)). Upon receiving this detection signal, the controller 100 operates the solenoid valves 151 and 152.
by changing the duty ratio signal to the second servo valve 5.
The spool member 54 of No. 0 is rapidly moved upward from the position (C) to the position (D). As a result, the moving speed of the pilot valve 84 also becomes rapid, and the shoe 86b is rapidly moved together with the piston shaft 85 in the direction of closing the discharge passage 81b. Therefore, the time delay from when the speed ratio becomes the minimum until the completion of operation of the direct coupling clutch valve DC can be reduced, and the operational responsiveness of the direct coupling clutch valve is improved.

Next, when the immediate position determination switch 58 detects that the shoe 86b has moved to the position immediately before the discharge path 81b is completely closed (the lower end of the spool member 54 is in position (d)), the switch 58 receives this detection signal. controller 100
changes the duty ratio signal to the solenoid valves 151 and 152 again, and this time slowly moves the spool member 54 of the second servo valve 50 upward, and the shoe 86
b closes the discharge passage 81b very slowly. As a result, with the ON operation of the direct coupling clutch valve DC,
It is possible to slow down the fluctuations in the thrust force of the motor plunger and the fluctuations in the volumetric efficiency, and it is possible to suppress the occurrence of shift shock at this time.

In the above example, the motor trunnion angle control device and the direct clutch device are linked 8! Although an example has been shown in which the operation of the direct-coupled clutch device is controlled using a structure, the present invention is not limited to this, and it goes without saying that the direct-coupled clutch device may be controlled independently. It is about.

In addition, in this example, the input shaft 1 and the pump cylinder 60
Although a continuously variable transmission has been described in which the support portion 70a of the pump swash plate 63 is connected to the motor cylinder 70, and the motor cylinder 70 is disposed around the outer periphery of the pump cylinder 60, the present invention is not limited to the direct coupling clutch device in such a continuously variable transmission. For example,
Instead of arranging the motor cylinder on the outer periphery of the pump cylinder, the clutch device according to the present invention may be used in a continuously variable transmission having a structure in which the pump cylinder and the motor cylinder are arranged coaxially and in a line. , the angle adjustment of the pump swash plate is variable and the configuration is similar to the motor trunnion in the above example, and the four motors are of fixed capacity, the input shaft is connected to the pump cylinder, and the pump cylinder and motor swash plate support part is connected. The direct coupling clutch device according to the present invention may be disposed in a continuously variable transmission configured such that the motor cylinder is coupled to the output shaft and the motor cylinder is coupled to the output shaft.

As described in detail in the 1899 invention, according to the present invention, when it is detected that the gear ratio has become "1", the direct coupling clutch valve is rapidly moved from the fully open position to the immediately preceding position, and then Since it is gradually moved from the immediately preceding position to the fully closed position, it is possible to shorten the time from when the gear ratio reaches 1" until the direct coupling clutch valve is closed, and the direct coupling clutch mechanism Not only does this reduce the delay in operation, but the closing of the closed circuit after the direct coupling clutch valve moves to the immediately preceding position is performed slowly, and the thrust to the motor plunger and fluctuations in volumetric efficiency caused by this interruption are gradually reduced. It can soften the shift shock and improve the driving feeling.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram of a continuously variable transmission having a direct coupling clutch device according to the present invention, FIG. 2 is a sectional view of the above continuously variable transmission, and FIG. 2 is a sectional view of the servo valve, FIG. 4 is a sectional view of the direct coupling clutch device, FIG. 5 is a perspective view showing the link mechanism, and FIGS. 6A to 6C are front views showing the operation of the cam forming the link mechanism. It is. 1...Input shaft 4...Shuttle valve 1
0... Charge pump 20... Forward/forward switching device 3
0.50...servo valve

Claims (1)

[Claims] 1) A hydraulic pump connected to an input shaft and a hydraulic motor connected to an output shaft are connected via a hydraulic closed circuit, and the capacity of either the hydraulic pump or the hydraulic motor is In a hydraulic continuously variable transmission in which the gear ratio between the input shaft and the output shaft can be adjusted steplessly through variable control, a direct coupling clutch valve that can connect and disconnect the closed circuit, and the direct coupling clutch valve are actuated. a direct coupling clutch actuator mechanism, a minimum gear ratio detection means for detecting that the gear ratio has become "1", and the direct coupling clutch valve moves from a fully closed position where the closed circuit is completely cut off to an open side by a predetermined amount. and an immediately preceding position detecting means for detecting that the direct coupling clutch valve is at the immediately preceding position, and when the direct coupling clutch valve is in a fully open position that completely opens the closed circuit, the minimum gear ratio detecting means detects that the gear ratio is "1". ”, the actuator mechanism is actuated to rapidly move the direct coupling clutch valve from the fully open position to the immediately preceding position, and the direct coupling clutch valve is moved to the immediately preceding position. When detected by the immediately preceding position detection means,
A direct coupling clutch device for a hydraulic continuously variable transmission, characterized in that the actuator mechanism slowly moves the clutch valve from the immediately preceding position to the fully closed position.