JPH02286429A - Variable speed control device for vehicle - Google Patents

Abstract

PURPOSE:To make valves smaller in size and smoothly control variable speed by introducing oil pressure regulated by a pressure regulating valve selectively by means of a selector valve to plural hydraulic clutches engaged with a speed change gear mechanism for speed-changing power transmitted to driven and driving wheels. CONSTITUTION:A speed change gear mechanism 21 and two transmission capacity variable type hydraulic multiple disk clutches 22L, 22R are housed in a housing 18 of a rear differential 17 to which power of an engine 11 is transmitted through a propeller shaft 16. The speed change gear mechanism 21 is provided with two sets of epicyclic gears 26H, 26L arranged around a main shaft 25 in a case 24, and sun gears 28H, 28L are engaged with the housing 18 through arresting clutches 31H, 31L consisting of one way clutches 32H, 32L and hydraulic clutches 33H, 33L. Oil pressure is selectively supplied to respective hydraulic clutches 33H, 33L by a selector valve after the oil pressure generated in a hydraulic power source is regulated by a pressure regulating valve.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention is applicable to a transmission control device for a vehicle, and in particular to a vehicle such as a four-wheel drive vehicle that drives both a main drive wheel and a slave drive wheel. The present invention relates to a speed change control device.

(Prior art) In a four-wheel drive vehicle that drives both front wheels and rear wheels,
For the purpose of avoiding the tight corner braking phenomenon, a system in which a transmission mechanism is provided in the power transmission system to one of the front and rear wheels has been proposed in Japanese Patent Laid-Open No. 62-203826 and other publications. The four-wheel drive vehicle disclosed in Japanese Patent Application Laid-Open No. 62-203826 has a parallel gear type transmission mechanism having two sets of transmission gears arranged in parallel in a center differential device, and a hydraulic clutch is interposed between the transmission mechanism strings. In addition, the transmission mechanism is provided with a switching clutch that connects the front and rear wheels by selecting one of the transmission gear sets of the transmission mechanism, and this switching clutch is driven by a hydraulic actuator to change the driving force distribution ratio between the front and rear wheels. Problems to be Solved) However, in the above-mentioned four-wheel drive vehicle, the first gear shift clutch is driven by a hydraulic actuator and the shift gear is selected by the shift clutch, so the problem is that the hydraulic actuator is indispensable and increases in size. was there.

Therefore, the present applicant has proposed a four-wheel drive vehicle in which a propeller shaft or the like is provided with a transmission mechanism in which a plurality of control elements are selectively restrained by hydraulic clutches to change speed.
This is proposed in the specification of No. 3-7845.

However, regarding the four-wheel drive vehicle according to the above-mentioned earlier application,
Since the hydraulic pressure to each hydraulic clutch is controlled only by the directional switching valve, the directional switching valve has not only a switching position that selectively engages and operates each hydraulic clutch, but also a neutral switching position that releases and operates all hydraulic clutches. This has disadvantages in that the directional switching valve becomes large and the speed change control by switching the directional switching valve lacks smoothness.

The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a speed change control device for a vehicle that is capable of reducing the size of the valve and performing smooth speed change control.

(Means for Solving the Problems) A vehicle speed change control device according to the present invention provides a vehicle that includes a main drive wheel and a sub-drive wheel, and that changes the speed of power transmitted to the sub-drive wheel. A transmission mechanism that is interposed in a transmission system and changes the speed of power transmitted to the driven wheels by selectively restraining and releasing a plurality of control elements; and a transmission mechanism that controls the control elements of the transmission mechanism in response to hydraulic pressure supplied from a hydraulic source. a plurality of hydraulic clutches each individually restrained by a force applied thereto; a pressure regulating valve regulating the hydraulic pressure generated by the hydraulic pressure source; and a switching valve selectively supplying the hydraulic pressure regulated by the pressure regulating valve to the hydraulic clutch. The gist is to have the following.

(Function) According to the vehicle speed change control device according to the present invention, since the hydraulic pressure regulated by the pressure regulating valve is selectively guided to the hydraulic clutch by the switching valve, the hydraulic pressure output from the pressure regulating valve to the switching valve is reduced. All the hydraulic clutches can be released, there is no need to set the switching valve to a neutral switching position, the switching valve can be made smaller, and speed change control can be performed smoothly.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

Figures 1 to 3 show one embodiment of the present invention, in which Figure 1 is a framework diagram of a power transmission system of a vehicle, Figure 2 is a sectional view of the main parts, and Figure 3 is a hydraulic circuit diagram.

In FIG. 1, 11 is an engine, and 12 is an engine 11.
The transmission 12 has an output shaft connected to a front differential 13.The front differential 13 has left and right front wheels 14FL and 14FR, and a gear mechanism 15 for direction change connects a propeller shaft 16. It is connected to the rear differential 17 via.

As shown in detail in FIG. 2, the rear differential 17 has an input shaft 19 rotatably supported at the front of the housing 18, and output shafts 20L and 20R rotatably supported at the left and right sides of the housing 18. transmission mechanism 2
1 and two hydraulic multi-plate clutches 22L with variable transmission capacity,
22R is accommodated. The input shaft 19 has a front end connected to the propeller shaft 16 via a joint or the like, and a bevel gear 19a fixed to the rear end. Output shaft 20L,
20R are the above-mentioned hydraulic multi-plate clutches 22L and 2, respectively.
2R is connected to the transmission mechanism 21, and the outer U in the vehicle width direction connects to the left and right rear wheels 23RL, 23R via an axle, etc.
R&: Connected.

In the transmission mechanism 21, a case 24 is rotatably housed in a housing 18, and an input shaft 19 is mounted on an outer peripheral wall of the case 24.
A bevel gear 24a meshing with the bevel gear 29a is fixedly provided, and the case 24 is connected to the front differential 13 and the engine 11 so as to be capable of transmitting power. This case 2
4, a main shaft 25 penetrates in the vehicle width direction and is rotatably supported, and two planetary gear sets 26H are arranged around the main shaft 25 inside.
, 26L are arranged. Planetary gear set 26H, 26L
are a ring gear 278.27L fixed to the inner wall of the case 24, a sun gear 28H128L rotatably provided to the main shaft 25, and these ring gears 27H,
27L and a plurality of planetary gears 29H, 29L meshing with sun gears 28H, 28L, the planetary gears 29H129L of these planetary gear sets 26H, 26L are each integrally supported by a carrier 30 having a generally rectangular cross section. These planetary gear sets 26H128L are sun gear 28
H engages with the housing 18 via the restraint clutch 31H, similarly, the sun gear 28L engages with the housing 18 through the restraint clutch 31L, and the carrier 30 is integrated with the main shaft 25 at the center of its inner circumference by a spline or the like. Rotatably coupled. As will be detailed later, the left planetary gear set 26
H connects the ring gear 27H and carrier 30 with a fixed sun gear 28H at a gear ratio that increases the speed of the power transmitted from the ring gear 27H to the carrier 30, and the right planetary gear set 26L connects the ring gear 27H and carrier 30 with the fixed sun gear 28L. Gear 27L and carrier 30 are connected to front wheel 14FL, 14FR and rear wheel 23R.
L.

23RR is connected at a gear ratio that makes the rotational speed substantially equal to that of the 23RR, that is, it is substantially directly connected (hereinafter referred to as direct connection).

The left restraint clutch 31H is constructed by interposing a one-way clutch 32H and a hydraulic clutch 33H in series between the sun gear 28H and the housing 18. The one-way clutch 32H is interposed between the cylindrical member 34H fixedly attached to the sun gear 281 and the sleeve 35H of the hydraulic clutch 33H, and only allows relative rotation in one direction between the cylindrical member 348 and the sleeve 35H. As will be explained in detail, this one-way clutch 32H is used when torque is transmitted from the ring gear 27H to the carrier 30, in other words, the one-way clutch 32H is connected to the rear wheel 23RL.
, 23RR, the cylindrical member 34H and the sleeve 35H are fixed and the sleeve 35H and the ring gear 2 are connected.
Relative rotation with 7H is prohibited. The hydraulic clutch 33M is
A plurality of plates 37H supported by splines or the like on the inner circumferential surface of a drum 36H integrally formed with the housing 18 and a plurality of plates 38H supported by splines or the like on the outer circumference of the sleeve 35H are arranged alternately in the axial direction so as to be able to make frictional contact with each other. death,
A piston 40H is slidably fitted into a cylinder hole 39H formed in the drum 36H. The piston 40H has an oil chamber 39H (designated with the same reference numeral as the cylinder hole) connected to a hydraulic circuit 41, which will be described later, in the cylinder hole 39H.
The plates 37H and 38H are pressed with a pressing force corresponding to the oil pressure in the oil chamber 39H. This hydraulic clutch 3
3H, the plates 37H and 381 (are pressed by the piston 40H and restrain the sleeve 35M to the housing 18 with a force corresponding to the oil pressure in the oil chamber 39H.

Further, the right restraint clutch 31L is constructed by interposing a one-way clutch 32L and a hydraulic clutch 33L in parallel between the right end outer peripheral portion of the sun gear 28L and the housing 18. The one-way clutch 32L is similar to the one-way clutch 32H of the left restraint clutch 31H described above, and includes a sleeve 35L fixed to the outer periphery of the right end of the sun gear 213L and a cylindrical member 34L fixed to the inner wall of the housing 18.
It is interposed between the sun gear 28L and the cylinder member 34L to prohibit relative rotation in one direction. This one-way clutch 32L also has a rear wheel 23RL.

When driving force is transmitted to 23RR, sun gear 28L is fixed to housing 18 to prevent rotation of sun gear 28L. The hydraulic clutch 33L includes a plurality of plates 37L connected by splines or the like to a drum 36L integrally formed in the housing 18, and a plurality of plates 38L connected to the sleeve 35L by splines or the like, arranged alternately in the axial direction so as to be able to frictionally contact each other. A piston 40L for pressing the drums 37L and 38L is slidably fitted into a cylinder hole 39L formed in the drum 36L. This piston 40L also defines an oil chamber 39L (designated with the same reference numeral as the cylinder hole) in the cylinder hole 39L, which is connected to a hydraulic circuit 41 to be described later, and the plate 37L is applied with a force corresponding to the oil pressure in this oil chamber 39L. , press 38L. In this hydraulic clutch 33L, the plates 37L and 38L are connected to the piston 40.
L is pressed and fastened, and the sun gear 28L is restrained to the housing 18 by a force corresponding to the oil pressure in the oil chamber 39L.

The left hydraulic multi-plate clutch 22L has a drum 42L fixed to the left end of the main shaft 25, a sleeve 43L fixed to the output shaft 20L, a plate 44L provided with splines etc. on the inner periphery of the drum 42L, and a spline provided on the outer periphery of the sleeve 43L. The piston 47L is connected to the plates 44L, 45L via a pressing member 48L to the plates 44L, 45L, and the plates 45L are arranged alternately in the axial direction so as to be in frictional contact with each other.
L is pressably engaged. A return spring 48L is compressed between the pressing member 46L and the sleeve 43L, and the return spring 48L connects the pressing member 46L to the plate 44L.

45L is biased in the direction of separation. Piston 47L
The plate 44L is slidably fitted into a cylinder hole 49L formed in the housing 18 to define a cylinder hole 49L (designated with the same reference numeral as the cylinder hole). , press 45L. In this hydraulic multi-disc clutch 22L, an oil chamber 49L is connected to a hydraulic circuit 41, hydraulic pressure is introduced from the hydraulic circuit 41, and the main shaft 25 and output shaft 20L are connected with a fastening force according to the hydraulic pressure in the oil chamber 49L. . Further, the right hydraulic multi-disc clutch 22R has the same configuration as the left hydraulic multi-disc clutch 22L, and the same parts are given the suffix R to distinguish them, and their explanation will be omitted.

This hydraulic multi-disc clutch 22R also has oil pressure introduced into the oil chamber 49L from the hydraulic circuit 41, and connects the main shaft 25 and the output shaft 20R with a fastening force corresponding to the oil pressure in the oil chamber 49R.

As shown in FIG. 3, the hydraulic circuit 41 includes a pump 51, an unload valve 52, a fail-safe valve 53, and three pressure control valves 54 and 55L.

55R and a shift valve 56, the pressure oil discharged by the pump 51 is regulated by the pressure control valves 55L and 55R through the unload valve 52 and the fail-safe valve 53, respectively, and the oil of the left and right hydraulic multi-disc clutches 22L and 22R is adjusted. Similarly, the pressure control valve 54
The pressure is regulated by the shift valve 56, and hydraulic pressure is selectively supplied to the oil chambers 39H, 39L of the left and right hydraulic clutches 33H, 33L. The pump 51 is a well-known vane pump or the like, and is driven directly by the crankshaft of the engine II or by a motor, etc., and pressurizes and discharges the oil in the reservoir tank 57. The unload valve 52 responds to the discharge pressure of the pump 51 and recirculates pressure oil to the reservoir tank 57 when the discharge pressure of the pump 51 exceeds a predetermined pressure. The fail-safe valve 53 has a housing formed with an inlet port connected to the unload valve 52, a drain port connected to the reservoir tank 57, and an outlet port connected in parallel to each pressure control valve 54, 55L, 55R. A spool valve 59 is housed within 58 and the housing 5
A return spring 60 for biasing the spool 59 in one direction is provided between the spool 59 on one side of the housing 58, and a solenoid 61 for biasing the spool 59 against the elastic force of the return spring 60 on the other side of the housing 58. It is being This fail-safe valve 53 has a solenoid 61 connected to a controller (not shown) and is controlled by the controller, and in the event of an abnormality such as a failure, the inlet port connected to the unload valve 52 is connected to the pressure control valves 54, 55L,
It is isolated from the outlet boat connected to 55R and communicates with the drain boat connected to the reservoir tank 57. Note that 62 is an accumulator, and the accumulator 62 stores pressure oil as is well known.

In the pressure control valve 54, a spool 64 is slidably accommodated in an accommodation hole 63a formed in a housing 63, and a return spring 65 is provided on one side of the housing 63 between the spool 64 and the spool 64 to bias the spool 64 in one direction. is compressed, and a solenoid 66 that urges the spool 64 against the elastic force of the return spring 65 is attached to the other side of the housing 63.
is provided. The housing 63 includes an inlet boat 67 connected to the fail-safe valve 53, an outlet boat 68 connected to the shift valve 56, a drain boat 69 connected to the reservoir tank 57, and a first control connected to the outlet boat 6. A second control boat 70b is formed that communicates with the boat 70a and the outlet boat 68 via a throttle 71, and a minute gap is formed in the spool 64 between the groove 64a and the peripheral wall surface of the accommodation hole 63a. Shallow groove 64
A variable throttle valve 2a is formed between the inlet port 67 and the outlet boat 68 by the groove 64a of the spool 64, and a variable throttle valve 2a is formed between the control boats 70a, 70b and the drain boat 69 by the shallow groove 64b of the spool 64.
A variable aperture 72b is configured between the two. This pressure control valve 54 is connected to the controller by a solenoid 66, and energizes the spool 64 with a biasing force according to the current value supplied from the controller. , 72b change with opposite characteristics to regulate the oil pressure output from the outlet boat 68.

As will be described later, the pressure control valve 54 is controlled so that the energization of the solenoid 66 is synchronized with the switching operation of the shift valve 56 and reduces the hydraulic pressure output from the outlet boat 68 when the shift valve 56 is switched. Ru.

The shift valve 56 has a spool 74 in the housing 73.
A return spring 75 is compressed on one side of the housing 73 to bias the spool 74 in one direction between the spool 74 and the spool 74 on the other side of the housing 73. A solenoid 76 is fixedly provided to actuate against the force. The housing 73 includes an inlet boat 77 connected to the pressure control valve 54, an outlet boat 78H connected to the left hydraulic clutch 33H, an outlet boat 78L connected to the right hydraulic clutch 33L, and a reservoir tank. Two drain boats contacted by 57 7
Further, grooves 74a, 74b, 74c are formed in the spool 74 to selectively communicate the outlet boats 78H, 78L to the inlet boat 77 or the drain boats 79a, 79b, respectively. The solenoid 76 is wired to the controller and energized by the controller to energize the spool 74 . This shift small valve 56 communicates between the inlet port 77 and the outlet boat 78H and between the drain boat 79b and the outlet boat 78H when the solenoid 76 is not energized (the state shown in the figure), and is connected to the left hydraulic clutch 33H. It guides the hydraulic pressure and also connects the inlet boat 77 and outlet boat 78 when the solenoid 76 is energized.
Between L and drain boat 78H and drain boat 79
a to guide hydraulic pressure to the right hydraulic clutch 33L.

The pressure control valves 55L and 55R have the same configuration as the pressure control valve 54 described above, and the outlet boat 68 of the pressure control valve 55L is connected to the left hydraulic multi-disc clutch 22L and is supplied to the hydraulic multi-disc clutch 22L. The hydraulic pressure is regulated according to the current value applied to the solenoid 66 from the controller, and similarly, the outlet boat 68 of the pressure control valve 55R is connected to the right hydraulic multi-disc clutch 22R to supply hydraulic pressure. Note that these pressure control valves 55L.

55R, the same parts as those of the pressure control valve 54 described above are given the same reference numerals, and the description thereof will be omitted.

Next, the operation of this embodiment will be explained.

In such vehicles, the left and right hydraulic multi-plate clutches 2
Front wheel 14F by changing the fastening force of 2L and 22R together
The driving force distribution ratio between L and 14FR and the rear wheels 23RL and 23RR can be adjusted, and the left and right hydraulic multi-disc clutches 22L,
By changing the ratio of the fastening force of 22R, the left and right rear wheels 2
The driving force distribution ratio of 3RL and 23RR can be adjusted, that is, the differential can be limited.

And the oil chamber 49 of each hydraulic multi-plate clutch 22L, 22R
Hydraulic pressure regulated according to the steering angle of the vehicle and the like is supplied to L and 49R by pressure control valves 55L and 55R, respectively, thereby improving the motion performance of the vehicle.

On the other hand, in this vehicle, when the sun gear 28H of the left planetary gear set 28H is fixed, the rear wheels 23RL and 23RR
The transmission power to the right planetary gear set 26 is increased.
When the L sun gear 28L is fixed, the rear wheels 23RL and 23
RR has 14FL front wheels.

The front wheel 14 is connected to the 14FR with a gear ratio of approximately 1 as described above.
It is directly connected to the engine 11 together with FL and 14FR. The sun gear 28H of the left planetary gear set 26H transmits power to the rear wheels 23RL and 23RR, and when hydraulic pressure is supplied to the hydraulic clutch 33H, the sun gear 28H is connected to the hydraulic clutch 33H.
The sun gear 28L of the right planetary gear set 26L is fixed by the one-way clutch 32H and the rear wheel 23R.
When the power is transmitted to L and 23RR, it is fixed by the one-way clutch 32L, and the rear wheel 23RL
, 23RR, when hydraulic pressure is supplied to the hydraulic clutch 33L, regardless of whether power is transmitted to the hydraulic clutch 33L.
Fixed by

Here, the oil chamber 49H of each hydraulic clutch 33H, 33L,
In 49H, the hydraulic pressure regulated by the pressure control valve 54 is switched by the shift valve 56 and guided selectively, but these pressure #control valve 54 and shift valve 56 are controlled depending on the vehicle condition such as braking or turning. control and further
When the shift valve 56 is switched, the pressure control valve 54 is controlled so that the hydraulic pressure supplied to the shift valve 56 is reduced. That is, for example, when the vehicle turns, the shift valve 56 supplies pressure oil to the hydraulic clutch 33H to engage (ON) the hydraulic clutch 33H and shift the rear wheels 23RL, 2.
3RR, and also supplies pressure oil to the hydraulic clutch 33L to engage the hydraulic clutch 33L (ON) when reversing or braking with the engine brake.
Directly connects 3RL and 23RR, and furthermore, rear wheel 23RL
, 23RR during normal straight-line driving where power is transmitted from the engine 11, each hydraulic clutch 338.33L is connected to the reservoir tank 57, and the one-way clutch 32L is used to control the sun gear 28L of the planetary gear set 26L.
and directly connects the rear wheels 23RL and 23RR. The pressure control valve 54 circulates pressure oil to the reservoir tank 57 during braking with the foot brake to release (OFF) L/ each hydraulic clutch 33H, 33L, and also switches in synchronization with the switching operation of the shift valve 56. During operation, the hydraulic pressure supplied to the shift valve 56 is temporarily lowered. Therefore, the vehicle can obtain high turning performance by increasing the speed of the power transmitted to the rear wheels 23RL and 23RR when turning without compromising straight-line stability, and when braking with the foot brake, the front and rear wheels can be separated and integrated. In addition, when braking with engine braking, a great braking effect can be obtained, and shift shock can also be reduced.

As mentioned above, in this embodiment, the pressure control valve 54
In order to selectively supply the hydraulic pressure regulated by the shift valve 56 to the hydraulic clutch 33H for increasing speed change and the hydraulic clutch 33L for direct gear change to change the transmission power to the rear wheels 23FL and 23FR, the pressure is increased. Hydraulic clutch 33M with control valve 54
, 33L can be adjusted, there is no need to set a neutral switching position on the shift valve 56, and the size can be reduced, and damage to mechanical parts due to simultaneous supply of hydraulic pressure to the hydraulic clutches 33H and 33L is also completely prevented. Furthermore, when the shift valve 56 is switched, the hydraulic pressure applied to the shift valve 56 is reduced by the pressure control valve 54, so that the shift shock can be minimized.

(Effects of the Invention) As explained above, according to the vehicle transmission control device according to the present invention, the hydraulic pressure regulated by the pressure regulating valve is selectively guided to a plurality of hydraulic clutches by the switching valve to select a hydraulic clutch. Since the switching valve is actuated in a consistent manner, the switching valve can be made smaller, and malfunction of the hydraulic clutch is prevented, so that mechanical parts are not damaged due to malfunction of the hydraulic clutch.

[Brief explanation of the drawing]

1 to 3 show a transmission control device for a vehicle according to an embodiment of the present invention, in which FIG. 1 is a frame diagram of a power transmission system of a vehicle, FIG. 2 is a cross-sectional view of the main parts, and FIG. is a hydraulic circuit diagram. 11...Engine 4FL, 14FR...Front wheel 1...Transmission mechanism 2L, 22R...Hydraulic multi-plate clutch 3RL, 23RR...Rear wheel 6H, 26L...Planetary gear set IH, 31L... - Restraint clutches 3H, 33L... Hydraulic clutch 4... Pressure control valve (pressure regulating valve) 6... Shift valve (switching valve)

Claims (3)

[Claims] (1) In a vehicle that is equipped with a main drive wheel and a sub-drive wheel and changes the speed of the power transmitted to the sub-drive wheels, selective restraint of a plurality of control elements interposed in the power transmission system to the sub-drive wheels is provided. , a transmission mechanism that changes the transmission power to the driven wheels when released; a plurality of hydraulic clutches that individually restrain the control elements of the transmission mechanism with forces corresponding to hydraulic pressure supplied from a hydraulic source; A speed change control device for a vehicle, comprising: a pressure regulating valve that regulates the hydraulic pressure generated by a hydraulic pressure source; and a switching valve that selectively supplies the hydraulic pressure regulated by the pressure regulating valve to the hydraulic clutch. (2) The speed change control device for a vehicle according to claim 1, wherein the pressure regulating valve temporarily lowers the hydraulic pressure output to the switching valve in synchronization with the switching operation of the switching valve. . (3) The transmission mechanism includes a plurality of planetary gear sets, and each of these planetary gear sets is one of a ring gear, a sun gear, or a carrier.
2. The vehicle speed change control device according to claim 1, wherein one of the control elements is a control element.