JPH04201725A - power transmission device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power transmission device for a vehicle that transmits power from a driving wheel to a driven wheel.

[Prior Art] Vehicle power transmission devices that transmit power from the driving wheels to the driven wheels have been known for a long time.For example, in front-wheel drive vehicles, a hiscus coupling is used to transmit the power from the front wheels to the driven wheels. Vehicles that transmit power to the rear wheels are often used.

However, in a power transmission device using a viscous coupling, the torque transmission characteristic (power transmission characteristic) with respect to the rotation speed difference between the front and rear wheels becomes, for example, a curve G1 in FIG. 9. With such torque transmission characteristics, the torque transmission n becomes considerably large in a region where the rotational speed difference is small, so there is a problem that the vehicle becomes close to a rigid four-wheel drive, and tight corner braking is more likely to occur when turning.

Therefore, a power transmission device has been proposed that uses an oil pump to transmit power from the front wheels to the rear wheels (
For example, see Japanese Patent Application Laid-open No. 104426/1983). In a power transmission device using such an oil pump, the discharge pressure of the oil pump is approximately proportional to the square of the difference in rotational speed.
The torque transmission characteristic with respect to the rotational speed difference between the rear wheels is, for example, as shown in curve G in FIG. Favorable torque transmission characteristics such as an increase in torque can be obtained.

[Problems to be Solved by the Invention] By the way, in general, when the brakes are applied while the vehicle is running, a brake lock phenomenon occurs if the brakes are too strong.

Therefore, ABS (anti-lock braking system), which automatically weakens the braking force when a brake lock phenomenon is detected, is often used.

For example, in a front-wheel drive vehicle, whether or not a brake lock phenomenon occurs in the front wheels is determined based on the vehicle speed based on the rotation speed of the rear wheels and whether or not the front wheel rotation speed is lower than the rear wheel rotation speed. It has become.

However, for FP-based vehicles, for example,
- In a four-wheel drive vehicle equipped with an oil pump as disclosed in Publication No. 104426, when a difference in rotational speed occurs between the front and rear wheels, torque is transmitted to the rear wheels, so accurate vehicle speed can be detected. become unable to do so. For this reason, A
There is a problem that when a BS is installed, its functions are not fully demonstrated, and it is practically difficult to install an ABS on such a four-wheel drive vehicle.

The present invention has been made in order to solve the above-mentioned conventional problems, and the present invention provides a power system that enables effective installation of ABS in a vehicle equipped with a power transmission means for transmitting the power of the driving wheels to the driven wheels. The purpose is to provide a transmission device.

Means for Solving the Problem] In order to achieve the above object, a first invention is a power transmission device for a vehicle, comprising a power transmission means capable of transmitting power from a driving wheel to a driven wheel, A power transmission device comprising a power transmission amount adjusting means that increases the amount of power transmitted when the driving wheel rotation speed is higher than the driven wheel rotation speed, and decreases the power transmission amount when the driving wheel rotation speed is lower than the driven wheel rotation speed. I will provide a.

A second invention is such that in the power transmission device according to the first invention, the power transmission amount adjustment means adjusts the power transmission IFI only when the absolute value of the difference between the driving wheel rotation speed and the driven wheel rotation speed is small. To provide a power transmission device characterized in that:

A third invention is the power transmission device according to the first invention, characterized in that the vehicle is front wheel driven and rear wheel driven, and the braking force of the front wheels is set to be greater than the braking force of the rear wheels. Provides a power transmission device.

A fourth invention is the power transmission device according to the first invention, wherein the power transmission means is an oil pump, and the power transmission amount adjustment means is a variable flow resistance means whose flow resistance characteristics differ depending on the relative rotational direction of the oil pump. A power transmission device is provided.

A fifth invention is a power transmission device for a vehicle equipped with an oil pump capable of transmitting power from a driving wheel to a driven wheel, wherein an oil suction passage and an oil discharge passage of the oil pump are respectively connected to a reservoir chamber. On the other hand, check valves are installed in both oil passages to regulate the flow of oil to the lisano/chamber side through holes, and one of the check valves is equipped with a spring that regulates the check function of the ball in the low oil flow range. A power transmission device is provided.

A sixth invention is the power transmission means according to the fifth invention, characterized in that the vehicle is front wheel driven and rear wheel driven, and the braking force of the front wheels is set to be greater than the braking force of the rear wheels. Provides a power transmission device.

A seventh invention provides a power transmission device according to the fifth invention, characterized in that a variable flow resistance means having a flow resistance characteristic different depending on the relative rotational direction of the oil pump is provided.

[Operations and Effects of the Invention] In general, the occurrence of the driving wheel locking phenomenon, and therefore the activation of ABS, occurs when the driving wheel rotation speed is lower than the driven wheel rotation speed and the difference between the rotation speeds is relatively small. .

According to the first invention, when the rotational speed of the driving wheels is lower than the rotational speed of the driven wheels, the amount of power transmitted from the driving wheels to the driven wheels decreases, and the accuracy of detecting the vehicle speed increases. Therefore, if the 8R3S is installed, the 8B will be determined based on the accurate vehicle speed.
S can be operated correctly, improving the braking performance of the vehicle.

According to the second invention, basically the same operation and effect as the first invention can be obtained.And, when the driving wheel rotation speed is lower than the driven wheel rotation speed, the area where the amount of power transmission is reduced. However, since it is set only in areas where the rotation speed difference is small, it is possible to effectively perform four-wheel drive in areas where the rotation speed difference is small, that is, in areas where ABS does not operate, and when accelerating or reversing. It is possible to prevent slippage and improve the running performance of the vehicle.

According to the third invention, basically the same operation and effect as the first invention can be obtained. The braking force of the front wheels, which are the driving wheels, is set to be large, and the front wheels are more likely to be brake-locked, so the effect of improving the operating characteristics of ABS is particularly effective.

According to the fourth invention, basically the same operation and effect as the first invention can be obtained. In addition, since an oil pump with a simple structure is used as the power transmission means, and a variable flow resistance means with a simple structure consisting of a combination of orifices etc. can be used as the power transmission adjustment means, the power transmission device is simple. be converted into

According to the fifth invention, the suction side is maintained at approximately atmospheric pressure by the reservoir chamber and the check valve, regardless of the discharge direction of the oil pump, and the characteristics of the discharge pressure with respect to the difference in rotational speed are stabilized.

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In a low oil flow region, that is, in a region where the rotational speed difference between the driving wheels and the driven wheels is small, the spring causes the check valve to check, and the oil flows into the brake chamber. For this reason, by installing a splinter on the check valve on the specified side, when the driving wheel rotation speed is lower than the driven wheel rotation speed, it is possible to virtually eliminate power transmission in the region where the rotation speed difference is small. Therefore, by accurately detecting the vehicle speed in the above region (A133 operating region), when the 8BS is installed, its operating characteristics can be greatly improved. , Chiff, Tsukuharuzo, etc. have a simple structure, so the power transmission device can be made into a simple structure.

According to the sixth invention, basically the same operation and effect as the fifth invention can be obtained.Then, the braking force of the front wheel, which is the driving wheel, is set to be large, and the brake lock occurs on the front wheel. Therefore, the effect of improving the operating characteristics of ΔB S is particularly effective.

According to the seventh invention, basically the same operation and effect as the fifth invention can be obtained. Furthermore, since the discharge pressure can be changed according to the relative rotational direction of the oil pump, fine control of the amount of power transmission can be performed.

[Example] Examples of the present invention will be specifically described below.

As shown in FIG. 3, in the FF-based four-wheel drive vehicle WD, the torque (power) of the crankshaft 2 of the horizontally mounted engine 1 is shifted by the transmission 3 and output to the transmission output shaft 4. It is now possible to do so.

A part of the torque of the transmission output shaft 4 is transmitted to left and right front wheels 7.8 (drive wheels) via a drive gear 5 and a front differential 6 (front differential device). .

The remaining torque of the transmission output shaft 4 is transmitted to the drive gear 5, the front differential 6 (ring gear only), the driven gear 10, and the first. It is adapted to be transmitted to the propeller shaft 13 via the second bevel gear 11.12. The torque of this propeller shaft 13 is transmitted to a drive gear shaft 14 via a power transmission device to be described later, and the torque of this drive shaft 14 is further transmitted to a third bevel gear 15 and a rear differential 16 (rear differential device). The signal is transmitted to the left and right rear wheels 17 and 18 (driven wheels) via the.

As shown in FIGS. 1 and 2, the power transmission device is connected from the propeller shaft 13 to the universal joint 21.
The torque input to the input shaft 23 via the front flange 22 is transmitted to the output shaft 26 via the oil pump 25, which will be explained later, and the torque of the output shaft 26 is transmitted via the rear flange 27 to the drive shaft. 14.

The oil pump 25 is provided with a substantially cylindrical case member 31 that forms the outer periphery of the oil pump 25, and the case member 31 rotates integrally with the output shaft 26. An internal gear 32 is spline-fitted to the inner peripheral surface of the case member 31. Inside the case member 31, the internal gear 3
A substantially disc-shaped rear plate 33 is disposed adjacent to the rear side (output shaft side) of 2. This rear plate 33 is adapted to rotate integrally with the case member 31. Also, within the case member 31, an internal gear 32
A substantially cylindrical front plate 34 integrally formed with the input shaft 23 is disposed adjacent to the front side of the input shaft 23 . Here, the gear surface (inner peripheral surface) of the internal gear 32, the front end surface of the rear plate 33, and the front plate 34
A substantially cylindrical pump chamber 30 is formed by the rear end surface of the pump. A cover member 38 is fitted into the inner peripheral surface of the case member 31 near the front end, and a clearance between the cover member 38 and the front flange 22 is sealed with a seal member 39.

Three bearing holes 29 are formed in the front plate 34 and extend through the front plate 34 in the axial direction of the input shaft 23, and a pin 35 is fitted into each of these bearing holes 29 so as to project into the pump chamber 30. There is.

In the pump chamber 30, each pin 35 is fitted with a pinion gear 36 that meshes with the internal gear 32, respectively. Note that the pinion gear 36 is not fixed to the pin 35.

Near the peripheral edge of the pump chamber 30, there are a gear surface (inner peripheral surface) of the internal gear 32 and a gear surface (outer peripheral surface) of each pinion gear 36.
Three substantially fan-shaped working chambers 40 are formed, and a substantially fan-shaped partition member 37 having a notched end in the circumferential direction is disposed in each working chamber 40. And each working chamber 4
0, near both ends of the partition member 37 in the circumferential direction (
A first oil boat 41 and a second oil port 42 are provided in the cutout portions, respectively. In addition, the first
, the second oil boats 41 and 42 are formed by perforating the front plate 34, respectively, and open into the working chamber 40.

Here, in each working chamber 40, the internal gear 32 and each pinion gear 36 mesh with each other to function as a gear pump. Each working chamber 40 is filled with oil, and when the front plate 34 rotates relative to the internal gear 32 in the A direction (the internal gear 32 rotates relative to the C1 direction), each pinion gear 3
6 rotates in the 81 direction around the pin 35, and at this time, oil in the working chamber 40 is discharged from the first oil port 41 and oil is sucked into the working chamber 40 from the second oil boat 42. Note that the pinion gear 36 rotates in the 81 direction and revolves in the A direction together with the front plate 34, so that it performs a so-called planetary rotation motion.

On the other hand, when the front plate 34 rotates relative to the internal gear 32 in the A2 direction (the internal gear 32
(relatively rotates in the C3 direction), each pinion gear 36 rotates in the B3 direction.
It rotates in two directions and flows from the first oil port 41 to the working chamber 40.
Oil is sucked into the working chamber 40, and oil in the working chamber 40 is discharged from the second oil boat 42. When flow resistance occurs in the discharged oil, the discharge pressure increases, and as the discharge pressure increases, the front plate 34 (
The amount of torque transmitted from the input shaft 23) to the internal gear 32 (output shaft 26) increases. In this way, torque (power) is transmitted from the propeller shaft 13 to the drive shaft I4.

Here, the rear plate 33 is pressed toward the internal gear 32 or the pinion gear 36 by oil pressure (back pressure) acting on its rear end surface. Since the rear end face of the partition member 37 and the front end faces of the rear plays 1 and 33 slide relative to each other, an appropriate clearance is set between them.

Here, the oil pump 2 is of a type in which the partition member 37 is slightly moved in the direction of its widening surface, thereby switching the oil passage and switching the oil flow resistance, that is, the discharge pressure, according to the relative rotation direction of the oil pump 25.
In No. 5, the above-mentioned clearance is set relatively large in order to facilitate movement of the partition member 37. Therefore, in this type of oil pump 25, oil inevitably leaks from the clearance portion. The viscosity of oil decreases as the temperature rises, so oil leaks as the temperature rises! iA increases,
Torque transmission amount decreases. In order to prevent such problems, when the partition member 37 is moved, the partition member 37 is made of a material with a higher coefficient of thermal expansion than the internal gear 32 or the pinion gear 36, and when the temperature of the oil rises, Due to thermal expansion of the partition member 37, the partition member 37
and the rear plate 33,
It is preferable to compensate for an increase in leakage amount due to a decrease in oil viscosity.

Each of the first oil boats 41 is connected to a first oil passage 46, each second oil port 42 is connected to a second oil passage 55, and the first oil passage 46 and the second oil passage 55 are connected to an orifice. 59. Note that the orifice 59 is formed by chamfering one piece of the partition member 37.

As schematically shown in FIG. 4, the first oil passage 46 communicates with the reservoir chamber 52 via a first communication passage 51, and a first check valve 47 is interposed in the first communication passage 51.
A first ball 48 is accommodated in the first check valve 47. Note that the reservoir chamber 52 is connected to the oil pump 2.
In order to stabilize the oil discharge pressure against changes in the relative rotation of the oil pump 5, the oil discharge pressure is maintained at atmospheric pressure at all times by a slide piston 53. Here, when the first oil boat 41 becomes the discharge side and the pressure of the oil in the first oil passage 46 increases, the first ball 48 basically closes the first communication passage 51. However, a spring 49 is provided that biases the first hole 48 in the direction in which the first check)<lub 47 is opened, and the first
The chigosokhalbu 47 is not closed.

Note that when the first oil boat 41 is on the suction side and negative pressure is applied to the first oil passage 46, the oil in the reservoir chamber 52 can freely flow into the first oil passage 46.

Further, the second oil passage 55 communicates with the reservoir chamber 52 via a second communication passage 58, and a second jack valve 56 is interposed in the second communication passage 58.
6 accommodates a second ball 57. Here, the second
42 becomes the discharge side and the second oil passage 55
When the pressure of the oil inside increases, the second ball 56
The communication path 58 is closed. Note that when the second oil boat 42 is on the suction side and negative pressure is applied to the second oil passage 55, the oil in the reservoir chamber 52 can freely flow into the second oil passage 55.

The operating characteristics of the power transmission device will be explained below.

■As schematically shown in Figure 4, when the front wheel rotation speed (propeller shaft rotation speed) is lower than the rear wheel rotation speed (drive shaft rotation speed), for example, when the vehicle is waiting to move forward,
The internal gear 32 and pinion gear 36 are indicated by arrows Y, Y
, rotate as shown. In addition. The rotation direction Y1 of the internal gear 32 in FIG. 4 is the rotation direction Y1 of the internal gear 32 in FIG.
The rotation direction Y of the pinion gear 36 in FIG. 4 corresponds to the rotation direction CI of the pinion gear 3 in FIG.
This corresponds to the rotation direction B1 of No. 6. In this case, the first oil boat 41 becomes the discharge side, and the second oil boat 42 becomes the suction side.

Here, if the rotational speed difference is below a predetermined value, the discharge pressure is low, and therefore the pressure of the oil in the first oil passage 46 is low, so that the spring 49 of the first check valve 47
The first ball 48 is held in a position such that the first check valve 47 is opened. For this reason, the first oil passage,
The oil in 46 mainly passes through the first communication passage 51, the reservoir chamber 52, and the second communication passage 58, and then flows into the second oil passage 5.
5, and substantially no flow resistance due to the orifice 59 occurs. Therefore, substantially no discharge pressure is generated in the oil pump 25, and no torque is transmitted from the front wheels to the rear wheels. In this case, the characteristics of the transmitted torque (generated oil pressure) with respect to the rotational speed difference are as shown in part A of the curve H1 in FIG. As mentioned above, such a region is the ABS operating region, but in this case, torque is not substantially transmitted to the rear wheel side (driven wheel side), so the vehicle speed can be detected accurately, and the ABS is activated. The operating characteristics are improved.

■Here, when the difference in rotational speed between the front wheels and the rear wheels exceeds a predetermined value, the discharge pressure of the oil pump 25 increases and the first ball of the first check valve 47 is opened, as schematically shown in FIG. 48 moves in a direction to close the first check valve 47 against the biasing force of the spring 49, and the first communication passage 51 is closed.

In addition, Y3. The Y direction is the same as the Y direction in FIG. 4, respectively.

At this time, the oil in the first oil passage 46 flows through the orifice 5.
9 into the second oil passage 55, a discharge pressure corresponding to the flow resistance of the orifice 59 is generated, and torque is transmitted from the front wheel side to the rear wheel side according to this discharge pressure.

In this case, the characteristics of the transmitted torque (generated oil pressure) with respect to the rotational speed difference are as shown in part 8 of curve H in FIG. 7. At this time, the vehicle enters a four-wheel drive state, and the driving performance becomes stable.

■As schematically shown in Fig. 6, for example, when the vehicle is moving forward, if the front wheel rotation speed (propeller shaft rotation speed) is higher than the rear wheel rotation speed (drive shaft rotation speed), the internal gear 32 and pinion gear 36 are arrow Y-,
Rotate as shown by Y e.

Here, the rotational direction Y5 of the internal gear 32 in FIG. 6 corresponds to the rotational direction C2 of the internal gear 32 in FIG. 2, and the rotational direction Y8 of the pinion gear 36 in FIG.
This corresponds to the rotation direction B of the pinion gear 36 in FIG. In this case, the second oil boat 42 becomes the discharge side, and the first oil port 41 becomes the suction side.

In this case, since the pressure of the oil in the second oil passage 55 increases, the second check valve 56 controls the second communication passage 55.
8 is closed. At this time, the oil in the second oil passage 55 flows into the first oil passage 46 through the orifice 59, so a discharge pressure corresponding to the flow resistance of the orifice 59 is always generated, and according to this discharge pressure, the front wheel side Torque is transmitted to the rear wheels. In this case, the characteristics of the transmitted torque (generated oil pressure) with respect to the rotational speed difference are as shown by the curve H1 in FIG. 8. Such a region may occur, for example, during acceleration or at low μ
When driving on the road, the front wheels 7.8 (see FIG. 3) may be slipping, but since the vehicle is in a four-wheel drive state at this time, the driving performance is stabilized.

[Brief explanation of the drawing]

FIG. 1 is an explanatory longitudinal cross-sectional view of a power transmission device showing an embodiment of the present invention. FIG. 2 is an explanatory cross-sectional view of an oil pump portion of the power transmission device shown in FIG. 1. FIG. 3 is a schematic diagram of an FF-based four-wheel drive vehicle equipped with the power transmission device shown in FIG. 1. FIG. 4 is a schematic diagram of the oil system of the power transmission device shown in FIG. 1, and shows a state when the front wheel rotation speed is lower than the rear wheel rotation speed and the difference in rotation speed is small. FIG. 5 is a schematic diagram of the oil system of the power transmission device shown in FIG. 1, and shows a state when the front wheel rotation speed is lower than the rear wheel rotation speed and the difference in rotation speed is large. FIG. 6 is a schematic diagram of the oil system of the power transmission device shown in FIG. 1, and shows a state when the front wheel rotation speed is higher than the rear wheel rotation speed. FIG. 7 is a diagram showing the characteristics of the transmission torque with respect to the rotation speed difference when the MiI wheel rotation speed is lower than the wheel rotation speed. FIG. 8 is a diagram showing the characteristics of the transmitted torque with respect to the rotation speed difference when the front wheel rotation speed is higher than the rear wheel rotation speed. FIG. 9 is a diagram showing the characteristics of the transmission torque with respect to the rotational speed difference of a conventional power transmission device. Wl) Vehicle, D...Power transmission device, 7.8...1i
ij wheel, 13 Blopelan Yaft, 14 Tribuno Yaft, 17.18 Rear wheel, 25・Oil pump, 32
Internal gear, 36, pinion gear, 41, first oil boat, 42, second oil boat, 46 first oil passage,
47. 1st Jenokhalbu, 48... 1st ball, 4
Splinter, 51 First communication passage, 52 Reservoir chamber, 55 Second oil passage, 56 Second check valve,
57 second ball, 58 second communication path.

Claims (7)

[Claims] (1) A power transmission device for a vehicle equipped with a power transmission means capable of transmitting power from the driving wheels to the driven wheels, which increases the amount of power transmitted when the driving wheel rotational speed is higher than the driven wheel rotational speed. 1. A power transmission device comprising a power transmission amount adjusting means that reduces the amount of power transmitted when the rotational speed of the driving wheels is lower than the rotational speed of the driven wheels. (2) In the power transmission device according to claim 1, the power transmission amount adjusting means is set to adjust the power transmission amount only when the absolute value of the difference between the driving wheel rotation speed and the driven wheel rotation speed is small. A power transmission device characterized by: (3) The power transmission device according to claim 1, wherein the vehicle is front wheel driven and rear wheel driven, and the braking force of the front wheels is set to be greater than the braking force of the rear wheels. Device. (4) In the power transmission device according to claim 1, the power transmission means is an oil pump, and the power transmission amount adjustment means is a variable flow resistance means whose flow resistance characteristics vary depending on the relative rotational direction of the oil pump. A power transmission device characterized by: (5) A power transmission device for a vehicle equipped with an oil pump capable of transmitting power from a driving wheel side to a driven wheel side, wherein an oil suction passage and an oil discharge passage of the oil pump are respectively communicated with a reservoir chamber; Both oil passages are equipped with check valves that use balls to regulate the flow of oil toward the reservoir chamber, and one of the check valves is equipped with a spring that regulates the check function of the ball in the low oil flow range. power transmission device. (6) The power transmission device according to claim 5, wherein the vehicle is front wheel driven and rear wheel driven, and the braking force of the front wheels is set to be greater than the braking force of the rear wheels. Device. (7) The power transmission device according to claim 5, further comprising variable flow resistance means having flow resistance characteristics that vary depending on the relative rotational direction of the oil pump.