JPH0257753A - Continuously variable transmission of static hydraulic type - Google Patents

Abstract

PURPOSE:To provide a compact continuous transmission by installing either of No.1 valve driving means for driving No.1 distribution valve and No.2 valve driving means for driving No.2 distribution valve inside of a cylinder block, and installing the other on the outside. CONSTITUTION:In a statical oil-hydraulic continuous transmission T, an eccentric shaft 63, i.e. No.1 valve driving means, to drive No.1 distribution valves 61, 61... is arranged inside of a cylinder block B while another eccentric shaft 64, i.e. No.2 valve driving means, to drive No.2 distribution valves 62, 62... is outside the same cylinder block B, so that centralized arrangement of the two valve driving means 63, 64 is avoided to lead to compacting of the transmission T. Particularly the eccentric shaft 63 is formed at the input shaft 2 penetrating the cylinder block B, so that a wide space is offset at the perimeter of the cylinder block B on the pump cylinder 7 side to ensure that output gear 3 etc. can be arranged compactly, which will contribute to compacting of the transmission T and enhancement of the degree of freedom in layout.

Description

DETAILED DESCRIPTION OF THE INVENTION A0 Object of the Invention (1) Industrial Application Field The present invention relates to a hydrostatic continuously variable transmission in which a hydraulic pump and a hydraulic motor are connected via a hydraulic closed circuit.

(2) Prior art The present applicant has proposed a hydrostatic continuously variable transmission that can reliably transfer hydraulic fluid between a hydraulic pump and a hydraulic motor and has high transmission efficiency. The cylinders are connected to each other to form a cylinder block,
An annular inner oil passage and an annular outer oil passage surrounding the oil passage are formed between a large number of annularly arranged cylinder holes of the pump cylinder and a large number of annularly arranged cylinder holes of the motor cylinder. and a plurality of first distributing valves which reciprocate between a radially outer position and an inner position to communicate the plurality of cylinder holes of the pump cylinder alternately with the two sleeve passages; A plurality of second distribution valves that reciprocate between inner positions and alternately communicate the plurality of cylinder holes of the motor cylinder with the two sleeve passages are respectively disposed radially, and at the outer end of each first distribution valve. engages a first eccentric wheel that provides reciprocating motion to the distribution valve as the cylinder block and the input member of the hydraulic pump rotate relative to each other; Accordingly, a second eccentric wheel that gives reciprocating motion to the distribution valve is engaged, and each cylinder hole of the pump cylinder is communicated with one oil passage during the discharge stroke and with the other oil passage during the suction stroke, and also communicates with the motor cylinder. A system has already been proposed in which each cylinder hole is communicated with one of the oil passages during the expansion stroke and with the other oil passage during the contraction stroke (Japanese Patent Laid-Open No. 62-496).
(See Publication No. 3).

(3) Problems to be Solved by the Invention In the configuration of the hydrostatic continuously variable transmission as described above, the first and second eccentric wheels that drive the first and second distribution valves are concentrated on the outer periphery of the cylinder block. As a result, the area around the cylinder block becomes thick, which is an obstacle to making the transmission more compact.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydrostatic continuously variable transmission that has high transmission efficiency (and is compact).

B0 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention combines a pump cylinder of a hydraulic pump and a motor cylinder of a hydraulic motor to form a cylinder block. The block includes an annular inner oil passage between a plurality of annularly arranged cylinder holes of the pump cylinder and an annularly arranged many cylinder holes of the motor cylinder, and an annular outer oil passage surrounding the oil passage. and a plurality of first distributing valves that reciprocate between radially outer and inner positions to alternately communicate the plurality of cylinder holes of the pump cylinder with the two sleeve passages; and a plurality of second distribution valves that reciprocate between positions and inner positions to alternately communicate a plurality of cylinder holes of the motor cylinder with both sleeve passages, respectively, are arranged radially, and drive the first distribution valve. 1st
One of the valve drive means and the second valve drive means for driving the second distribution valve is disposed inside the cylinder block, and the other is disposed outside the cylinder block.

(2) Operation When the first valve driving means drives the first distribution valve as the hydraulic pump rotates, the cylinder hole in the discharge stroke of the hydraulic pump supplies high-pressure hydraulic oil to one of the oils through the first distribution valve. The cylinder hole which is in the suction stroke sucks hydraulic oil from the other oil passage.

On the other hand, when the second valve driving means drives the second distribution valve as the hydraulic motor rotates, the cylinder hole in the expansion stroke of the hydraulic motor is supplied with high pressure hydraulic oil from the one oil passage, and also in the contraction stroke. One cylinder hole discharges the hydraulic oil that has completed its expansion work to the other oil passage.

In this way, the hydraulic fluid is repeatedly exchanged between the hydraulic pump and the hydraulic motor, and power is transmitted from the hydraulic pump to the hydraulic motor.

Since one of the first and second valve drive means is disposed inside the cylinder block and the other on the outside, their concentrated arrangement can be avoided.

(3) Examples An embodiment of the present invention will be described below with reference to the drawings.

First, in Fig. 9, U is an automobile power unit,
It is constructed by housing and supporting an engine E, a hydrostatic continuously variable transmission T of the present invention, and a differential device Df in a casing C.

A crankshaft 1 of an engine E and an input shaft 2 of a continuously variable transmission T coaxially arranged on the right end side thereof are connected via a torque damper D. Further, the output gear 3 serving as the output section of the continuously variable transmission T is meshed with the ring gear of the differential device Df. Left and right drive shafts 4 and 4' of the differential device Df are arranged parallel to the crankshaft 1 and input shaft 2, and drive left and right axles (not shown).

In FIGS. 1 and 2, the continuously variable transmission T includes a fixed displacement swash plate type hydraulic pump P disposed around the input shaft 2, and a variable displacement pump P disposed around the input shaft 2 on the left side. It consists of a capacity type swash plate type hydraulic motor M.

The hydraulic pump P includes a pump cylinder 7 that concentrically surrounds the input shaft 2, and a large number of odd number of cylindrical holes 8, 8, . Among the many pump plungers 9.9... and these pump plungers 9,9...
The pump swash plate lO contacts the outer end of the pump swash plate 10, and the pump swash plate 10 is tilted at a certain angle with respect to the axis of the pump cylinder 7, with the virtual trunnion axis O1 orthogonal to the axis of the pump cylinder 7 as the center. The pump swash plate holder 12 supports the back surface of the swash plate 10 via a thrust roller bearing 11 to hold the swash plate 10 therein. The pump cylinder 7 is rotatably supported by the casing C via a ball bearing 6, and is also relatively rotatably supported by the input shaft 2 via a needle bearing 13. The output gear 3 is fixed to the outer periphery of the pump cylinder 7 in close proximity to the ball bearing 6. In addition, the pump swash plate holder l2 is connected to a drive gear 3 that drives a replenishment pump 38, which will be described later.
9 is spline-coupled to the input shaft 2.

Thus, the pump swash plate 10 can give reciprocating motion to the pump plunge portion 9.9 when the human power shaft 2 is rotated, thereby repeating the suction and discharge strokes.

The boss of the drive gear 39 is rotatably supported by the casing C via a ball bearing 41, and is prevented from moving outward in the axial direction by a splitter 36 secured to the outer peripheral surface of the input shaft 2. Ru.

In order to improve the ability of the pump plunger 9 to follow the pump swash plate 10, a coil spring 15 is installed in the cylinder hole 8 to bias the pump plunger 9 in the direction of expansion.

On the other hand, the hydraulic motor M has a motor cylinder 1 that concentrically surrounds the input shaft 2 and is arranged to the left of the pump cylinder 7.
7, and a large and odd number of cylinder holes 1 arranged in an annular manner surrounding the rotation center of the motor cylinder 17.
8.18..., a large number of motor plungers 19, 19... and these motor plungers 1
9.19... A motor swash plate 20 that comes into contact with the outer end of the motor swash plate 20, a trunnion shaft 22 with a semicircular cross section that supports the back surface of this motor swash plate 20 on a flat surface via a thrust roller bearing 21, and further this trunnion. The swash plate anchor 23 rotatably supports the cylindrical surface of the shaft 22. The swash plate anchor 23 has a cylindrical cylinder holder 24 connected to its right end.
It is also fixed to the casing C with bolts 26.

The motor cylinder 17 is rotatably supported by the cylinder holder 24 via a ball bearing 25, and is also relatively rotatably supported by the input shaft 2 passing through the center thereof via a needle bearing 14.

In order to prevent the axial movement of the trunnion shaft 22 while allowing rotation of the trunnion shaft 22 by a predetermined angle, the bolt 29 is inserted through an arc-shaped long hole 28 centered on the axis Ot of the trunnion shaft 22, which is bored in the swash plate anchor 23. is fixed to one end surface of the trunnion shaft 22 (see FIGS. 2 and 8).

The motor swash plate 20 is actuated by the rotation of the trunnion shaft 22 between an upright position perpendicular to the axis of the motor cylinder 17 and a maximum tilt position tilted at an angle. Now, motor cylinder 1
With the rotation of 7, the motor plungers 19, 19... can be given reciprocating motion to repeat the expansion and contraction strokes.

In order to improve the followability of the motor plunger 19 with respect to the motor swash plate 20, a coil spring 30 that biases the motor plunger 19 in the direction of expansion is compressed in the cylinder hole 18.

The pump cylinder 7 and the motor cylinder 17 are integrated with each other to form a cylinder block B.

The cylinder block B is sandwiched between a flange 31 projecting from the outer circumference of the input shaft 2 and a seat plate 33 secured to the outer circumference of the input shaft 2, and is prevented from moving in the axial direction. These flange 31 and seat plate 33 are subjected to a surface treatment with high wear resistance and lubricity so as not to interfere with the relative rotation of input shaft 2 and cylinder block B, or the flange 31 and seat plate 33 and cylinder block B are A washer is inserted between them.

The left end of the input shaft 2 is connected to the motor swash plate 20 and the trunnion shaft 22.
and extends through the swash plate anchor 23, and is spline-coupled to the outer periphery of this left end portion, and is split into two.
Between the support tube 45 and the swash plate anchor 23, which are fixed with
A retainer 46 and a thrust roller bearing 47 are sequentially installed from the swash plate anchor 23 side. The left end portion of the input shaft 2 is rotatably supported by the swash plate anchor 23 via a needle bearing 48 and the retainer 46.

The input shaft 2 includes a hemispherical centering body 50 that engages with the inner peripheral surface of the pump swash plate 10 so as to be tiltable in all directions relative to the inner peripheral surface of the motor swash plate 20, and a centering body 50 that is tiltable in all directions relative to the inner peripheral surface of the motor swash plate 20. A hemispherical centering body 51 that can be engaged is fitted, and these provide an alignment effect to the pump swash plate 10 and the motor swash plate 20.

The alignment action of each swash plate 10.20 is strengthened, and the rotation direction between the pump swash plate 10 and the pump plunge +9.9... group, and the motor swash plate 20 and the motor plunge +19.19... group is strengthened. To prevent slippage, each swashplate 10.20 has a spherical end 9a, 19a in the corresponding plunger 9.19.
Spherical recesses 10a and 20a are respectively formed to engage the spherical recesses 10a and 20a.

A hydraulic closed circuit is formed between the hydraulic pump P and the hydraulic motor M as follows.

In the cylinder block B, there are cylinder holes 8, 8, . . . groups of the pump cylinder 7 and cylinder holes 1 of the motor cylinder 17.
8.18...An annular inner oil passage 52 and an outer oil passage 53 arranged concentrically around the input shaft 2 between the groups, and an annular partition wall and an outer oil passage between both side passages 52 and 53. The same number of first valve holes 54, 54 as the cylinder holes 8.8... and 18.18... radially penetrate the outer peripheral wall of 53.
... and the second valve holes 55.55... and the adjacent cylinder holes 8.8... and the first valve holes 54.54... are connected to each other by a large number of pump boats a, a. ..., adjacent cylinder holes 18.18... and second valve holes 55.55.
A large number of motor boats b, b.
... is provided.

The inner oil passage 52 is connected to the cylinder block B and the input shaft 2.
In order to prevent oil leakage from the inner oil passage 52, a pair of rotating and sliding grooves are formed between the input shaft 2 and the cylinder block 8 on both left and right sides of the inner oil passage 52. A seal ring 43°43 is interposed.

Further, the outer oil passage 53 is formed as an annular groove cut into the outer circumference of the cylinder block B, and the open surface of this annular groove is closed by a sleeve 60 welded to the outer circumference of the cylinder block B.

Spool-type first distribution valves 61, 61, . . . are installed in the first valve holes 54, 54, .
... also has a spool-type second distribution valve 62°62.
... are rubbed together.

An eccentric shaft 63 as a first valve driving means formed in the middle part of the human power shaft 2 so as to be surrounded by the inner ends of the first distribution valves 61, 61, etc. is engaged with the inner ends of the first distribution valves 61, 61... In order to force the coupling, a forcing shaft 67 in a concentric relationship with the eccentric shaft 63 is engaged with the outer ends of the first distribution valves 61, 61, . . . .

In addition, an eccentric ring 64 as a second valve driving means surrounding the second distributors 462, 62 is engaged via a ball bearing 66 to the outer ends of the second distributors 462, 62, and in order to force their engagement. The outer ends of the second distribution valves 62, 62, .

As shown in FIG. 3, the eccentric shaft 63 has an eccentric direction line X
1, the input shaft 2 occupies a position offset by a predetermined distance ε1 from the center of the input shaft 2. The eccentric direction line X is set at a position retarded by a certain angle θ from the virtual trunnion axis O1 of the pump swash plate lO in the rotational direction R of the input shaft 2.

Therefore, when relative rotation occurs between the input shaft 2 and the pump cylinder 7, each first distribution valve 61 moves a distance twice the eccentricity ε1 in the first valve hole 54 by the eccentric shaft 63 to the pump cylinder. 7 between radially inner and outer positions.

In FIG. 6, the discharge area of the hydraulic pump P is shown as D, and the suction area is shown as S. In the discharge area, the first distribution valve 61 is moving from a position Nl perpendicular to the eccentric direction line x1 (hereinafter referred to as the eccentric neutral position) to the inner position side, and the corresponding pump bow) a is moved to the outer oil passage 53. The cylinder hole 8 is in communication with the inner oil passage 52 and is disconnected from the inner oil passage 52, and the hydraulic oil is force-fed from the cylinder hole 8 to the outer oil passage 53 by the pump plunger 9 during the discharge stroke.

In the suction region S, the first distribution valve 61 is at an eccentric neutral position N,
The corresponding pump boat a is communicated with the inner oil passage 52 and disconnected from the outer oil passage 53, and the pump plunger 9 is moved from the inner oil passage 52 to the cylinder hole 8 during the suction stroke. Hydraulic oil is sucked in.

The discharge area of the hydraulic pump P is retarded by an angle θ1 compared to the case where the eccentric direction line X1 coincides with the virtual trunnion axis, and the suction area S is set to be wider than the discharge area.

As shown in FIGS. 1, 2, and 4, the eccentric wheel 64 swings between a clutch-on position n and a clutch-off position f via a pivot shaft 76 parallel to the input shaft 2 in the cylinder holder 24. movably linked.

The eccentric direction line Xt of the eccentric ring 64 is the trunnion axis O
1 to a certain angle θ2 in the rotation direction R of the motor cylinder 17.
The eccentricity is set to an advanced position, and the eccentricity is ε2 at the clutch-on position n and ε2 at the clutch-off position f.
The larger ε.

Therefore, when the motor cylinder 17 rotates when the eccentric wheel 64 occupies the clutch-on position IZn, each second distribution valve 6
2 is a stroke of the motor cylinder 1 by the eccentric wheel 64 at the second valve hole 55 with a distance twice the eccentricity ε2.
7 between radially inner and outer positions.

In Fig. 5, the expansion Ml jI area of the hydraulic motor M is EX
, the contraction region is denoted by sh. In the fat swelling region Ex, the second distribution valve 62 is moving from the eccentric neutral position N to the inner position side, and communicates the corresponding motor boat b with the outer oil passage 53, and disconnects the inner oil passage 52. , high-pressure hydraulic oil is supplied from the outer oil passage 53 to the cylinder hole 18 of the motor plunger 19 during the expansion stroke.

In the contraction region sh, the second distribution valve 62 is at the eccentric neutral position N2.
The corresponding motor boat b is communicated with the inner oil passage 52 and disconnected from the outer oil passage 53, and the inner oil passage 52 is moved from the cylinder hole 18 of the motor plunger 19 during the contraction stroke. Hydraulic oil is drained to.

Further, at the eccentric neutral position N, the second distribution valve 62 disconnects the corresponding motor boat b from both oil passages 52 and 53.

The fat expansion region Ex of the hydraulic motor M has an eccentric direction line X2 aligned with the trunnion axis 0. The angle is advanced by an angle θ2 compared to the case where the angle θ2 is matched with the angle θ2, and the contraction area sh is set to a wider angle than the fat expansion area Ex.

Further, when the motor cylinder 17 rotates when the eccentric wheel 64 occupies the clutch-off position f, each second distribution valve 62 is caused by the eccentric wheel 64 to have an eccentric amount ε in the second valve hole 55, as shown in FIG. The motor cylinder 17 is reciprocated between an inner position and an outer position in the radial direction with a stroke of twice the distance, and at the inner and outer positions, the second distribution valve 62
The outer oil passage 53 is opened to the outside of the cylinder block B.

A pair of the pump boats a are arranged per cylinder hole 8 in a direction perpendicular to the sliding direction of the first distribution valve 61. Furthermore, one pair of the motor boats b are arranged per cylinder hole per day in a direction perpendicular to the sliding direction of the second distribution valve 62. In this way, the corresponding ports a and b can be opened and closed with a relatively short stroke of each distribution valve 61, 62 while ensuring a large overall passage area for the pump port a and the motor bow 1-b.

Referring again to FIG. 4, a contact plate 79 is fixed to the circumferential wall of the eccentric wheel 64 on the opposite side to the pivot shaft 76 with screws 80, and a camshaft 81, which is pivotally supported by the casing C, is attached to the contact plate 79.
This is engaged so as to push the eccentric wheel 64 toward the clutch-off position f. An operating wire 83 is connected to a clutch lever 82 fixed to the outer end of the camshaft 81, and a return spring 84 of the lever 82 is compressed between the clutch lever 82 and the casing C. In addition, the eccentric wheel 64
is biased toward the clutch-on position n by the set spring 85. The set spring 85 is compressed between the support ring 75 and a retainer 87 fixed to the outer periphery of the eccentric ring 64 with screws 86 . In the above, the camshaft 81 and the set spring 85 constitute a drive mode converting means that changes the drive mode of the eccentric wheel 64 with respect to the second distribution valves 62, 62, . . . .

The eccentric wheel 64 is normally held at the clutch-on position n by the force of the set spring 85, but the operation wire 83
When the camshaft 81 is rotated in the direction of the arrow by the pulling operation, it is swung to the clutch off position r.

When the pump swash plate holder 12 of the hydraulic pump P is rotated from the input shaft 2 while the eccentric wheel 64 is held at the clutch-on position n, the pump swash plate 10 causes the pump plungers 9, 9, .
Exhalation and suction strokes are applied alternately to ....

The pump plunger 9 pumps hydraulic oil from the cylinder hole 8 to the outer oil passage 53 while passing through the discharge area, and pumps hydraulic oil from the inner oil passage 52 to the cylinder hole 8 while passing through the suction area S. Inhale.

The high pressure hydraulic oil sent to the outer oil passage 53 is supplied to the hydraulic motor M.
Hydraulic oil is supplied to the cylinder hole 18 of the motor plunger 19 located in the expansion oil head Ex, while the hydraulic oil is discharged from the cylinder hole 18 to the inner oil passage 52 by the motor plunger 19 located in the contraction region sh.

During this period, the pump cylinder 7 receives reaction torque from the pump swash plate 10 via the pump plunger 9 in the discharge stroke, and the motor cylinder 17 receives reaction torque from the motor plunger 1 in the expansion stroke.
The cylinder block B is rotated by the sum of the reaction torque received from the motor swash plate 20 via the motor 9, and the rotational torque is transmitted from the output gear 3 to the differential gear Df.

At this time, since the output gear 3 is arranged close to the ball bearing 6 that supports the cylinder block B, the drive reaction force that the output gear 3 receives from the actuating device Df is reliably transferred to the casing C via the ball bearing 6. This prevents the cylinder block B from tilting due to drive reaction force.

The gear ratio of the output gear 3 to the input shaft 2 is given by the following equation.

Capacity of the hydraulic pump P Therefore, by changing the capacity of the hydraulic morph M to a value consisting of zero, it is possible to change the transmission ratio to the required value consisting of one. Moreover, since the capacity of the hydraulic motor M is determined by the stroke of the motor plunger 19, by tilting the motor swash plate 20 from the upright position to the inclined position, the gear ratio can be controlled steplessly up to a value of 1. Can be done.

By the way, in the hydraulic pump P, the suction area S is set to be wider than the discharge area, so even if the back pressure of the pump plunger 9 in the suction stroke is much lower than that of the pump plunger 9 in the discharge stroke, the cylinder hole The inhalation efficiency of 8 can be effectively increased. As a result, the overall efficiency of the hydraulic pump P can be improved even if the discharge area is sacrificed to some extent.

In addition, in order to increase the efficiency as much as possible, the suction area S should be set at 180°.
It is best to do so.

In addition, in the discharge area, the eccentric direction line X1 of the eccentric shaft 63 is set to the virtual trunnion axis 0. The angle θ compared to the case where it matches
Since the pump plunger 9 is retarded by 1, the pump plunger 9 receives a large compressive load from the pump swash plate 10 from the time when it contracts by an amount exceeding the maximum extension point. As a result, the maximum bending moment generated in the pump plunger 9 is reduced, so that the prying phenomenon between the pump plunger 9 and the opening edge of the cylinder hole 8 is alleviated, and the friction loss due to this phenomenon is significantly reduced.

On the other hand, in the hydraulic motor M, since the contraction area sh is set at a wider angle than the expansion area Ex, the back pressure of the motor brush jar 19 during the contraction stroke can be sufficiently lowered, even if the expansion area Ex is sacrificed to some extent. , the efficiency of the hydraulic motor M can be improved as a whole.

In addition, in order to increase the efficiency as much as possible, the contraction area sh should be set to 180
It is best to use @.

In addition, the expansion region Ex is advanced by an angle θ compared to the case where the eccentric direction line X2 of the eccentric ring 64 coincides with the trunnion axis 0□, so the motor plunger 19 in the fat expansion stroke reaches the maximum expansion point. The thrust reaction force of the motor swash plate 20 is released earlier. As a result, the maximum bending moment generated in the motor plunger 19 is reduced, so that the prying phenomenon between the motor plunger 19 and the opening edge of the cylinder hole 18 is alleviated, and the friction loss due to this phenomenon is significantly reduced.

During such operation, if the eccentric wheel 64 is swung to the clutch-off position, the second distribution valve 62 will release the high-pressure outer oil passage 5.
3 is opened to the outside of the cylinder block B, high-pressure hydraulic oil is no longer supplied to the hydraulic motor M, and power transmission between the hydraulic pump P and the hydraulic motor M is cut off. That is, a so-called clutch-off state is obtained.

While the hydraulic pump P and hydraulic motor M are in operation, the pump swash plate 1
0 receives thrust loads in opposite directions from the pump plungers 9, 9, . It is supported by the input shaft 2 via the pump swash plate holder 12, the drive gear 39 and the shaft 36, and the motor swash plate 2o
The thrust load received by the thrust roller bearing 21
, the input shaft 2 via the trunnion shaft 22, the swash plate anchor 23, the thrust roller bearing 47, the support tube 45, and the stopper 44. Therefore, the thrust load merely causes a tensile stress on the input shaft 2, and does not act on the casing C supporting the shaft 2 at all.

In such a hydrostatic continuously variable transmission T, the eccentric shaft 63 that drives the first distribution valves 61, 61, ie, the first valve driving means is located inside the cylinder block B, and the second distribution valve 6
Since the eccentric wheels 64, that is, the second valve drive means that drive 2.62... are respectively disposed on the outside of the cylinder block B, it is possible to avoid central arrangement of both valve drive means, and to make the transmission T more compact. can be achieved.

In particular, since the eccentric shaft 63 is formed on the input shaft 2 passing through the cylinder block B, a large space is secured on the outer periphery of the cylinder block B on the pump cylinder side, in which the output gear 3 etc. can be arranged compactly. This can contribute to making the transmission T more compact and increasing the freedom of layout.

2, 7, and 8, a speed change control device 93 for controlling the angle of the motor swash plate 20 is connected to the trunnion shaft 22. As shown in FIGS. This speed change control device 93 is
A sector gear 96 is fixed to the other end of the trunnion shaft 22 by a bolt 94 and a pair of knock pins 95, 95, a worm gear 97 meshes with the sector gear 96, and a drive shaft 98 is connected to the worm gear 97, which is capable of forward and reverse rotation. The worm gear 97 is rotatably supported by a gear box 101 fixed to the casing C with bolts 100 via bearings 102 and 103. Further, the stator of the electric motor 99 is fixed in place in the casing C.

In the above, the sector gear 96 and the worm gear 97 constitute a speed reduction device 106 that can reduce the rotation of the drive shaft 98 and transmit it to the trunnion shaft 22, but becomes locked when receiving a reverse load from the trunnion shaft 22.

Therefore, when the electric motor 99 is rotated forward or reverse, the rotation is reduced and transmitted from the worm gear 97 to the sector gear 96, and further transmitted to the trunnion shaft 22, which rotates the rotation in the upright direction of the motor swash plate 20 or It can be rotated in the tilting direction.

Furthermore, when the electric motor 99 is stopped and the motor swash plate 20 is held at an arbitrary angle, the motor swash plate 20 receives a moment from the motor plungers 19, 19, etc. in the upright or tilting direction, and the moment is transferred to the trunnion shaft. 22 to the sector gear 96, the sector gear 96 cannot drive the worm gear 97, so both gears 96 and 97 are in a locked state and do not allow rotation of the trunnion shaft 22. Therefore, the motor swash plate 20 is securely held in its current position.

In order to regulate the upright position and tilted position of the motor swash plate 20 by the electric motor 99, an arc-shaped regulation groove 104 concentric with the sector gear 96 is bored, and the sector gear 96 is slidably engaged with the regulation groove 104. A matching stopper pin 105 is fixed to the gear box 101.

Referring again to FIGS. 1 and 2, a main oil passage 108 is bored in the center of the input shaft 2 and has a dead end at the back. The open end of the main oil passage 10B is communicated with an oil reservoir 110 at the bottom of the casing C via an oil filter 109 and a replenishment pump 38, and the replenishment pump 38 is driven by the drive gear 39. Therefore, while the input shaft 2 is rotating, the oil sump i1 is always
The oil in the oil filter 109 is removed by the replenishment pump 38.
It is fed to the main oil passage 10B through the oil passage.

The oil sent to the main oil passage 108 is sent to the inner oil passage 52 via a radial supply hole 111 provided in the input shaft 2. In this way, the hydraulic closed circuit between the hydraulic pump P and the hydraulic motor M is replenished with leaked hydraulic oil.

The main oil passage 108 is provided with a check valve 112 that prevents oil from flowing backward from the inner oil passage 52 .

Therefore, during reverse load operation, that is, during engine braking, the hydraulic motor M performs a pump action and the hydraulic pump P performs a motor action, so that the outer oil passage 53 is at low pressure and the inner oil passage 52 is at high pressure. Instead, the hydraulic oil attempts to flow back from the inner oil passage 52 to the main oil passage 108, but this back flow is blocked by the check valve 112. In this way, the reverse load is reliably transmitted from the hydraulic motor M to the hydraulic pump P, and a good engine braking effect can be obtained.

C1 Effects of the Invention As described above, according to the present invention, the pump cylinder of a hydraulic pump and the motor cylinder of a hydraulic motor are combined to form a cylinder block, and this cylinder block includes a plurality of pump cylinders arranged in an annular manner. An annular inner oil passage and an annular outer oil passage surrounding the oil passage are provided between the cylinder hole of the motor cylinder and a large number of annularly arranged cylinder holes of the motor cylinder. a plurality of first distribution valves that reciprocate between the cylinder holes of the pump cylinder and alternately communicate the cylinder holes of the pump cylinder with the two ground passages; and a plurality of second distribution valves that alternately communicate a plurality of cylinder holes with the two ground passages, respectively, are arranged radially, and drive the first valve driving means for driving the first distribution valve and the second distribution valve. Since one of the second valve drive means is disposed inside the cylinder block and the other on the outside, hydraulic oil can be transferred between the hydraulic pump and the hydraulic motor without relative rotation of the pump cylinder and motor cylinder. In addition, the reciprocating distribution valves have extremely little leakage of hydraulic oil, resulting in high transmission efficiency. Furthermore, since the first and second valve driving means can be avoided from being arranged in a concentrated manner, the transmission can be made more compact, and each valve driving means can be designed with a greater degree of freedom.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional plan view of a hydrostatic continuously variable transmission, FIG. 2 is a longitudinal sectional rear view of FIG. 1, and FIG. -■ line sectional view, Figure 4 is the IV-IV line sectional view of Figure 1, Figure 5 is the V-V line sectional view of Figure 1 (clutch on state), Figure 6 is the operation of Figure 5. Figure (clutch off state), Figure 7 is a sectional view taken along the ■-■ line in Figure 2,
FIG. 8 is a view taken in the direction of the ■ arrow in FIG. 2, and FIG. 9 is a longitudinal cross-sectional rear view of the main parts of an automobile power unit equipped with the hydrostatic continuously variable transmission. B...Cylinder block, E...Engine, M...
・Hydraulic motor, P... Hydraulic pump, T... Hydrostatic continuously variable transmission, 1... Crankshaft, 2... Input shaft, 3... Output gear as output part, 7. ...Pump cylinder, 8...
Same cylinder hole, 9...pump plunger, lO...
Pump swash plate, 12... Pump swash plate holder, 17...
Motor cylinder, 18... Same cylinder hole, 19...
Motor plunger, 20... Motor swash plate, 52...
Inner oil passage, 53... Outer oil passage, 54... First valve hole,
55...Second valve hole, 61...First distribution valve, 62...
- Second distribution valve, 63... Eccentric shaft as first valve driving means, 64... Eccentric wheel as second valve driving means, 81.
85...Camshaft and set spring constituting drive mode converting means Fig. 4 Fig. 6 Fig. 3 Fig. 5 Fig. 8 Fig. 7

Claims (6)

[Claims] (1) The pump cylinder of the hydraulic pump and the motor cylinder of the hydraulic motor are combined to form a cylinder block, and this cylinder block includes a large number of cylinder holes arranged in an annular manner for the pump cylinder and an annular arrangement for the motor cylinder. An annular inner oil passage and an annular outer oil passage surrounding the oil passage are provided between the plurality of cylinder holes, and
a plurality of first distribution valves that reciprocate between a radially outer position and an inner position to alternately communicate the plurality of cylinder holes of the pump cylinder with the oil passages; and a plurality of second distribution valves that reciprocate between positions and alternately communicate the plurality of cylinder holes of the motor cylinder with the two oil passages, each of which is arranged radially, and a first valve that drives the first distribution valve. One of the driving means and the second valve driving means for driving the second distribution valve is placed inside the cylinder block,
A hydrostatic continuously variable transmission characterized in that the other is placed on the outside. (2) In the cylinder block described in item (1), an input shaft that rotates relative to the cylinder block to drive the hydraulic pump is disposed in the center of the cylinder block, and an eccentric shaft formed on this input shaft is connected to a plurality of eccentric shafts. A hydrostatic continuously variable transmission characterized in that the first valve driving means is configured by engaging with the inner end of a first distribution valve. (3) In the item described in item (1), the hydrostatic continuously variable transmission is characterized in that the second valve driving means is connected to a driving mode converting means that can change the driving mode for the second distribution valve. Machine. (4) The hydrostatic continuously variable transmission according to item (2), characterized in that an output portion is formed in the cylinder block. (5) The hydrostatic continuously variable transmission according to item (1), wherein the driving mode of the first valve driving means with respect to the first distribution valve remains unchanged. (6) In the device described in item (1), the driving manner of the first valve driving means with respect to the first distribution valve remains unchanged, and the driving manner of the second valve driving means with respect to the second distribution valve may be changed. A hydrostatic continuously variable transmission characterized in that a driving mode converting means is connected.