JPH11152052A - Power steering gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power steering gear that offers an excellent steering feeling. SOLUTION: A control valve is provided to control the supply of working fluid to a power cylinder in dependence on the steering torque inputted into an input shaft 1, to which an output shaft 2 is coupled for relative rotation. Between the input shaft 1 and the output shaft 2, a first planetary gear drive 51 and a second planetary gear drive 52 are interposed both using a sun gear 53 in common. The first planetary geardrive 51 has a first ring gear 55 round the sun gear 53 by way of a first planetary gear 54, while the second planetary gearing 52 has a second ring gear 57 round the sun gear 53 by way of a second planetary gear 56. The first planetary gear 54 is joined on to the input shaft 1, and the second planetary gear 56 is joined on to the output shaft 2. The second ring gear 57 is held against rotation, and the first ring gear 55 is mounted with an operating rod 59 used for operating the control valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power steering device for an automobile or the like.

[0002]

2. Description of the Related Art As a power steering apparatus of this kind, the present applicant has proposed an improved technique described in Japanese Patent Application Laid-Open No. 9-99850.

[0003] The conventional power steering apparatus is a power steering apparatus which supplies steering oil to a power cylinder in accordance with a steering torque input to an input shaft of a steering mechanism to obtain a steering assisting force. A control valve that controls supply and discharge of hydraulic oil to and from the input shaft, and an output shaft that is connected to the input shaft so as to be relatively rotatable and that transmits a steering torque input to the input shaft.

A cylindrical moving member which moves in the axial direction by the relative rotation of the input shaft and the output shaft, and a lever which rotates with the movement of the moving member in the axial direction and operates a control valve are provided. Have.

The moving member includes a first sleeve slidably and rotatably fitted to the input shaft, and a second sleeve connected to the first sleeve so as to be relatively rotatable. The first sleeve is connected to the output shaft so as to be relatively movable in the axial direction and is not rotatable relative to the output shaft, and the second sleeve is connected to the fixed portion so as to be movable only in the axial direction.

[0006] Each of the first sleeve and the second sleeve has a cam groove inclined with respect to the rotational direction, and an engagement pin implanted in the input shaft engages with the cam groove of the first sleeve. The end of the lever is engaged with the cam groove of the second sleeve, whereby the moving member moves in the axial direction by the relative rotation between the input shaft and the output shaft, and the moving member moves in the axial direction. , The lever rotates, and the lever operates the control valve.

[0007]

In the conventional example, since the engaging pin slides in the cam groove of the sleeve, the sliding resistance may increase. Further, since the steering torque is once converted into the axial movement of the sleeve, and then converted into the rotational movement of the lever to operate the control valve, the conversion efficiency may be reduced. For this reason, there is a possibility that a slight operation delay may occur in the operation of the control valve in response to the input of the steering torque.

The present invention has been devised in view of the above-mentioned conventional circumstances, and has as its object to provide a power steering device capable of obtaining an excellent steering feeling.

[0009]

SUMMARY OF THE INVENTION Therefore, the invention according to claim 1 is a power supply for supplying and discharging hydraulic oil to a power cylinder to obtain a steering assisting force in accordance with a steering torque input to an input shaft of a steering mechanism. In the steering device, a control valve for supplying and discharging hydraulic oil to and from the power cylinder is provided, and an output shaft is connected to the input shaft so as to be relatively rotatable, and a steering torque from the input shaft is transmitted. A first planetary gear device in which a sun gear is shared between an input shaft and an output shaft and a first ring gear is provided on the outer periphery of the sun gear via a first planetary gear, and a first planetary gear is provided on the outer periphery of the sun gear via a second planetary gear A second planetary gear device provided with a two-ring gear, wherein the first planetary gear is connected to an input shaft, and the second planetary gear is connected to an output shaft; And unrotatable one of the second ring gear, is provided a valve operating means on the other, it is to operable in the configuration control valve by the valve operating means.

According to a second aspect of the present invention, in the configuration of the first aspect, the first planetary gear unit and the second
The planetary gear set is housed in a housing, and the valve operating means is attached to the first ring gear or the second ring gear, and the valve operating means penetrates the housing.

According to a third aspect of the present invention, in the first aspect, the first planetary gear unit and the second
The planetary gear device is accommodated in a housing, and a filling member for filling an axial gap is provided between the housing and the first ring gear or the second ring gear provided with the valve operating means.

Further, the invention according to claim 4 is configured such that, in the structure of the invention according to claim 3, the filling member is a thrust bearing.

According to a fifth aspect of the present invention, in the configuration of the first aspect, the first planetary gear unit and the second
The planetary gear device is housed in a housing, and the housing is provided with gear operating means capable of rotating the ring gear from the outside in contact with the outer periphery of the first or second ring gear which is not rotatable. Configuration.

In such a configuration, in a state where the relative rotation does not occur between the input shaft and the output shaft, the rotation of the input shaft causes the first planetary gear to rotate around the sun gear while rotating. At the same time as revolving, the output shaft rotates and the second planetary gear revolves around the sun gear while rotating. At this time, since one of the first ring gear and the second ring gear is not allowed to rotate, the sun gear rotates by the rotation of the first planetary gear and the second planetary gear, and the input shaft and the output shaft rotate in synchronization. Will be. In addition, since the rotations of the first planetary gear and the second planetary gear are synchronized, the ring gear provided with the valve operating means does not rotate, and the valve operating means does not operate the control valve.

In a state where the ground contact resistance of the wheels is large and the relative rotation occurs between the input shaft and the output shaft of the steering mechanism,
The first ring gear or the second ring gear provided with the valve operating means rotates in accordance with the steering torque input to the input shaft, and the valve operating means directly operates the control valve.

That is, when a relative rotation occurs between the input shaft and the output shaft, a difference between the rotation amount of the first planetary gear connected to the input shaft and the rotation amount of the second planetary gear connected to the output shaft is generated. Will occur. Here, the first planetary gear and the second planetary gear mesh with the same sun gear, and one of the first ring gear and the second ring gear meshing with the first planetary gear and the second planetary gear, respectively, cannot rotate. For example, when the first ring gear is provided with a valve operating means and the second ring gear is not rotatable, the difference in the amount of rotation between the first planetary gear and the second planetary gear is the rotation of the first ring gear. Will appear. When the first ring gear rotates, the valve operating means provided on the first ring gear operates the control valve.

That is, in a state where relative rotation occurs between the input shaft and the output shaft, the ring gear provided with the valve operating means rotates according to the steering torque input to the input shaft. This means that the valve operating means operates the control valve.

When the control valve is opened, hydraulic oil is guided from the control valve to the power cylinder.

As a result, a steering assisting force by the power cylinder is obtained for a leftward or rightward steering operation of the steering mechanism.

Here, a control valve for controlling the supply of hydraulic oil to the power cylinder is directly operated by valve operating means,
Since this valve operating means is provided on the ring gear of the first planetary gear device or the second planetary gear device, sliding resistance and the like are reduced as much as possible, and smooth operation is achieved.

Therefore, a power steering device capable of obtaining an excellent steering feeling can be obtained.

According to the second aspect of the present invention, since the valve operating means is mounted on the first ring gear or the second ring gear, the valve is mounted after the first ring gear and the second ring gear are assembled in the housing. The operation means can be attached, and the assembling work is facilitated.

According to the third aspect of the present invention, the provision of the filling member reduces the axial play gap between the first ring gear or the second ring gear provided with the valve operating means and the housing. And smooth rotation of the first ring gear or the second ring gear is achieved.

According to the fourth aspect of the present invention, since the filling member is a thrust bearing, the rotation resistance of the first ring gear or the second ring gear provided with the valve operating means can be reduced.

According to the fifth aspect of the present invention, by providing the gear operating means which can externally operate the first ring gear or the second ring gear which is not rotatable, the ring gear can be rotated to the neutral position in the rotational direction. Alignment is easy.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view of a power steering apparatus showing an embodiment of the present invention, FIG. 2 is an explanatory view including a sectional view taken along line AA of FIG. 1, and FIG. 3 is a view taken along line AA of FIG. FIG. 4 is a sectional view taken along line BB of FIG.

In FIG. 1, reference numeral 1 denotes a hollow input shaft. A steering wheel (not shown) is connected to the input shaft 1 to input a steering torque. An output shaft 2 is connected to the input shaft 1 so as to be rotatable relative to the input shaft 1. The input shaft 1 and the output shaft 2 are a housing 3 formed by connecting a cylindrical housing 3a and a gear housing 3b with a collar 3c. It is rotatably accommodated in the inside. Reference numerals 4 and 5 denote bearings for supporting the input shaft 1 and the output shaft 2.

A pinion shaft 8 is formed on the output shaft 2, and the pinion shaft 8 meshes with a rack shaft 9 for steering a steering link (not shown).

A power cylinder 13 is attached to the rack shaft 9, and the power cylinder 13 is mounted on the rack shaft 9.
And a pair of cylinder chambers 15L and 15R facing each other on both sides of the piston 14 attached to the piston.

Reference numeral 16 denotes a torsion bar inserted into the hollow interior of the input shaft 1. The torsion bar 16 has an appropriate torsional elasticity. The ends are connected to the output shaft 2 by serrations 18. Thereby, the output shaft 2
Is connected to the input shaft 1 via the torsion bar 16,
The torsion bar 16 can be relatively rotated with respect to the input shaft 1 by being twisted.

A control valve 20 controls the supply of hydraulic oil to the power cylinder 13 in accordance with the steering torque input to the input shaft 1. The control valve 20 is disposed in contact with the housing 3 and is configured as follows.

That is, reference numeral 24 denotes a body of the control valve 20 which has a spool valve housing hole 2 substantially parallel to the input shaft 1.
5 are formed. One end of the spool valve housing hole 25 is sealed by a plug 26, and the inside thereof is
A large diameter portion 25a is formed on one end (sealing end side), and a small diameter portion 25b is formed on the other end. Reference numeral 27 denotes a retaining ring for controlling the removal of the plug 26.

Reference numeral 28 denotes a first spool valve slidably housed in the spool valve housing hole 25. The first spool valve 28 has the inside of the spool valve housing hole 25 and a first oil chamber 29 on one end side. It is divided into the second oil chamber 30 on the end side. Also,
The body of the first spool valve 28 is reduced in diameter, thereby defining a third oil chamber 31 in a substantially central portion of the spool valve housing hole 25.

A section of the third oil chamber 31 with respect to the first oil chamber 29 is formed by a poppet portion 28a formed by tapering and expanding the first spool valve 28 on the large diameter portion 25a side of the spool valve housing hole 25. Is the large diameter portion 2 of the spool valve housing hole 25.
This is achieved by contacting a step 25c between the small oil tank 5a and the small diameter part 25b to cut off the communication between the first oil chamber 29 and the third oil chamber 31. Therefore, the first oil chamber 29 and the third oil chamber 29
The first spool valve 28 is provided between the first oil chamber 29 and the oil chamber 31.
The poppet 28a moves to the side and the poppet 28a is separated from the step 25c to allow communication.

The division of the third oil chamber 31 with respect to the second oil chamber 30 is achieved by a seal ring 32 provided on the outer periphery of the body of the first spool valve 28.

An end of the first spool valve 28 on the side of the first oil chamber 29 is extended in the axial direction to form an insertion portion 28b, and the insertion portion 28b is formed in a blind hole 33 formed in the plug 26.
Is inserted inside.

Further, a concave tapered surface 35 is formed at an end of the first spool valve 28 on the second oil chamber 30 side.

Reference numeral 36 denotes a communication oil passage which connects the first oil chamber 29 and the second oil chamber 30. The communication oil passage 36 is formed in the first spool valve 28 in this embodiment. That is, the communication oil passage 36 is formed in the body of the first spool valve 28 so as to face the first oil chamber 29 and to have a diametrical through-hole 36 a formed therein.
And an axial hole 36b communicating with the through hole 36a and opening to the second oil chamber 30.

A second spool valve 37 is slidably accommodated in the other end of the spool valve accommodation hole 25. In this embodiment, the second spool valve 37 has a convex tapered surface 38 which can be seated on the tapered surface 35 on the first spool valve 28 side on one end side, and a flat surface 39 on the other end side. ing. Further, the other end side of the second spool valve 37, that is, the tip portion on which the flat surface 39 is formed, projects into a through hole 40 formed in the body 24 substantially perpendicularly to the spool valve housing hole 25, and will be described later in detail. It is in contact with the valve operating means provided on the ring gear described below.

A supply spring 42 is accommodated in the first oil chamber 29. One end of the supply spring 42 contacts the plug 26, and the other end contacts the first spool valve 28. To the second oil chamber 30 side. Accordingly, in the first spool valve 28, the poppet portion 28a is in contact with the step portion 25c of the spool valve accommodating hole 25 in the normal state, and the communication between the first oil chamber 29 and the third oil chamber 31 is shut off.

Reference numeral 43 denotes a discharge spring housed in the second oil chamber 30. One end of the discharge spring 43 contacts the first spool valve 28 and the other end contacts the second spool valve 37. The two-spool valve 37 is urged in a direction protruding from the valve body 24. That is, the discharge spring 43 connects the second spool valve 37 to the first spool valve 28.
The first spool valve 28 and the convex tapered surface 38 of the second spool valve 37 do not come into contact with each other. For this reason, in the normal state, the second spool valve 37 does not close the communication oil passage 36 formed in the first spool valve 28 at the end on the second oil chamber 30 side, and opens the communication passage 36. State.

The control valve 20 is disposed in a pair opposite to both sides of a valve operating means provided on a ring gear, which will be described in detail later. The first oil chamber 29 of one of the control valves 20 has power via a passage 44L. The first oil chamber 29 of the control valve 20 communicates with one of the cylinder chambers 15L of the cylinder 13 and a passage 44R.
Through the other cylinder chamber 15R of the power cylinder 13
Is in communication with The second oil chamber 3 of each control valve 20
0 communicates with the drain passage 46, and the third oil chamber 31 communicates with the supply passage 47 for hydraulic oil.

Between the input shaft 1 and the output shaft 2, a first
A planetary gear set 51 and a second planetary gear set 52 are provided. The planetary gear device 51 includes a cylindrical sun gear 53 rotatably mounted on the outer periphery of the input shaft 1, a first planetary gear 54 meshing with the sun gear 53, and a first planetary gear provided on the outer periphery of the sun gear 53. The first ring gear 55 meshing with the first ring gear 55 is configured as a main element. The second planetary gear set 52 is provided with a sun gear 53 common to the first planetary gear set 51, a second planetary gear 56 meshed with the sun gear 53, and a second planetary gear 56 provided on the outer periphery of the sun gear 53. Second
The ring gear 57 is configured as a main element.

The first planetary gear 54 of the first planetary gear device 51 has a support shaft 58 rotatably supporting the first planetary gear 54 mounted on a radial flange 1 a formed on the input shaft 1. It is connected to the shaft 1.

On the outer periphery of the first ring gear 55 of the first planetary gear set 51, an operating rod 5 as a valve operating means is provided.
9 are attached. The steering rod 59 has its base end 5
9a is attached to the outer periphery of the first ring gear 55, and the tip 59b is arranged facing the control valve 20. That is, the operation rod 59 penetrates the housing 3 (3a) and
0, extends into a through hole 40 formed in the body 24,
The flat side surface 59c is the second spool valve 37 of the control valve 20.
In contact with the flat surface 39.

The second planetary gear 56 of the second planetary gear device 52 has a support shaft 60 rotatably supporting the second planetary gear 56 mounted on a radial flange 2 a formed on the output shaft 2. It is connected to the shaft 2.

A pair of notches 61 are formed on the outer periphery of the second ring gear 57 of the first planetary gear set 52, thereby forming two planes 62 parallel to the axial direction.

The housing 3 has
, A bolt 63 as a gear operating means is screwed and fixed. Reference numeral 64 denotes a lock nut of the bolt 63. A pair of bolts 63 as the gear operating means are provided facing the notch 61 of the second ring gear 57,
The tips of the second ring gear 57 are in contact with the flat surfaces 62, thereby making the second ring gear 57 unrotatable.

Further, a bolt 6 as the gear operating means is provided.
3 is capable of rotating the second ring gear 57 by advancing one side and retreating the other with respect to the plane 62 of the second ring gear 57, whereby the second ring gear 57 is rotated.
It is possible to easily align the ring gear 57 to the neutral position. Further, the forward or backward operation of the bolt 63 is sufficient by loosening the lock nut 64 and rotating the bolt 63, and this operation can be operated from the outside.

A thrust bearing 65 as a closing member is provided between the first ring gear 55 to which the operating rod 59 as the valve operating means is attached and the housing 3 (3a). Thrust bearing 65 as the closing member
Reduces the axial play gap between the first ring gear 55 and the housing 3 (3a), and reduces the first ring gear 5
5, the rotation resistance of the first ring gear 55 can be reduced.
Smooth rotation of is achieved.

A cut-off valve 81 is provided in a pair corresponding to the control valve 20.
The operation rod 59 provided on the ring gear 55 is disposed opposite to both sides of the operation rod 59.

The cutoff valve 81 includes a bottomed cylindrical cylinder 83 housed and fixed in a cylinder housing hole 82 formed in the body 24 common to the control valve 20.
And a plunger 84 slidably housed in the housing 3. The cylinder housing hole 82 is open to the through hole 40, and the tip of the plunger 84 protrudes into the through hole 40 and faces each other with the operation rod 59 interposed therebetween.

A pressure chamber 85 is formed between the bottom of the bottomed cylindrical cylinder 83 and the plunger 84, and the pressure in the pressure chamber 85 causes the plunger 84 to project into the through hole 40. It has become. On the other hand, a cylindrical plug 8 is provided at the end of the cylinder 83 on the side of the through hole 40.
6 is screwed and fixed, and a spring member 87 is provided between the plug 85 and the plunger 84 to urge the plunger 84 toward the pressure chamber 85. When the pressure in the pressure chamber 85 is smaller than the spring force of the spring member 87 and when the two are in opposition to each other, the plunger 84 has an operating rod 59 provided on the first ring gear 55.
, And oppose each other with a predetermined gap.

The hydraulic oil in the first oil chamber 29 of the corresponding control valve 20 is led into the pressure chamber 85 of the cutoff valve 81. That is, the pair of control valves 20
Of these, a passage 44L communicating with the first oil chamber 29 of one of the control valves 20 has a peripheral groove 88 formed on the outer periphery of the cylinder 83 of the one cutoff valve 81 and a through hole opened at the bottom of the peripheral groove 88. Through 89, communicates with the pressure chamber 85;
As a result, the first control valve 20 has the first
The hydraulic oil in the oil chamber 29 is guided. A passage 44 </ b> R communicating with the first oil chamber 29 of the other control valve 20 has a peripheral groove 88 formed on the outer periphery of the cylinder 83 of the other cutoff valve 81 and a through hole opened at the bottom of the peripheral groove 88. Through 89, communicates with the pressure chamber 85;
As a result, the first control valve 20 has the first control valve 20 in the pressure chamber 85.
The hydraulic oil in the oil chamber 29 is guided.

Reference numeral 91 denotes a hydraulic pump for supplying hydraulic oil to the supply passage 47. In the middle of the supply passage 47, a check valve 92 is provided to allow the hydraulic oil to flow from the hydraulic pump 91 to the third oil chamber 31 of each control valve 20 and to prevent the flow in the reverse direction. An accumulator 93 capable of holding the pressure in the supply passage 47 at a predetermined pressure is connected to the supply passage 47 downstream of the check valve 92.

A motor 94 rotationally drives the hydraulic pump 91. The motor 94 is driven and stopped based on a detection signal of a pressure switch 95 for monitoring the pressure in the supply passage 47 downstream of the check valve 92. Is controlled.

The inside of the through-hole 40 formed in the body 24 of the control valve 20 and the inside of the cylindrical housing 3a communicate with the reservoir 96 of the hydraulic oil through the drain passage 46.

In this configuration, when a steering wheel (not shown) connected to the input shaft 1 is steered and a steering torque is input to the input shaft 1, the steering torque is output via the torsion bar 16. Transmitted to shaft 2,
A steering link (not shown) is steered through the rack shaft 9.

Here, when the relative rotation does not occur between the input shaft 1 and the output shaft 2, the first planetary gear 54 rotates around the sun gear 53 while the input shaft 2 rotates. At the same time, the output shaft 2 rotates and the second planetary gear 56 rotates while the sun gear 53 rotates.
Orbit around. At this time, the first ring gear 55
Alternatively, since one of the second ring gears 56 is not allowed to rotate, the sun gear 53 rotates by the rotation of the first planetary gear 54 and the second planetary gear 56, and the input shaft 1 and the output 2 rotate in synchronization. become. Further, since the rotations of the first planetary gear 54 and the second planetary gear 56 are synchronized, the first ring gear 55 provided with the operating rod 59 as the valve operating means does not rotate, and the operating rod 59 is controlled by the control valve. 20 is not operated.

On the other hand, when the ground resistance of a wheel (not shown) is large, the torsion bar 16 is twisted and the relative rotation between the input shaft 1 and the output shaft 2 occurs, thereby causing the first shaft to rotate.
The operating rod 59 provided on the ring gear 55 operates the control valve 20 to supply and discharge hydraulic oil to and from the power cylinder 13, so that a steering assist force by operating hydraulic pressure is obtained.
This will be described step by step.

First, the operating oil in the supply passage 47 is supplied to an accumulator 93 provided downstream of the check valve 92.
And is constantly maintained at a predetermined pressure.
That is, the pressure of the hydraulic oil in the supply passage 47 is monitored by the pressure switch 95,
When the internal pressure is lower than the predetermined pressure, the motor 94 is rotated based on the detection signal of the pressure switch 95 and the hydraulic pump 91 is driven to rotate, so that the supply passage 4 is rotated.
The pressure of the hydraulic oil in 7 is increased. On the other hand, when the pressure in the supply passage 47 reaches a predetermined pressure, the pressure switch 95 detects this, and the motor 94 and the hydraulic pump 91
Stop the rotational drive of. Therefore, each of the control valves 2
That is, the working oil of a predetermined pressure is always guided into the third oil chamber 31 of the zero.

At this time, in a state where the relative rotation does not occur between the input shaft 1 and the output shaft 2, that is, in the neutral position of the steering operation, the first ring gear 55 does not rotate as described above. The operating rod 59 provided on the first ring gear 55
Is in the neutral position shown in FIG. 1 and does not operate each control valve 20. For this reason, the first spool valve 28 of each control valve 20
The second spool valve 37 and the second spool valve 37 are both in the neutral state shown in FIG. 1, and the supply of the hydraulic oil to the power cylinder 13 is shut off.

That is, the first spool valve 28 of each control valve 20 is in a normal state, and the first oil chamber 29 formed in the spool valve accommodation hole 25 by the first spool valve 28
The second oil chamber 30 and the third oil chamber 31 are partitioned from each other, and the mutual communication between the oil chambers is blocked. That is, the first spool valve 28 is urged toward the second oil chamber 30 by the supply spring 42, and the poppet portion 28a of the first spool valve 28 is in contact with the step portion 25c of the spool valve housing hole 25. The communication between the first oil chamber 29 and the third oil chamber 31 is blocked. Further, a seal ring 32 seals between the second oil chamber 30 and the third oil chamber 31. Therefore, the third oil chamber 31 communicating with the hydraulic oil supply passage 47 communicates with the first oil chamber 29 communicating with the passage 44L or 44R, and the second oil chamber 29 communicating with the drain passage 46.
The hydraulic oil is supplied to the third oil chamber 31 so as not to be supplied to either the power cylinder 13 or the drain passage 46.

Although the second spool valve 37 of each of the control valves 20 is urged by the discharge spring 43 in a direction to protrude from the body 24, the taper surface 38 at the distal end thereof is movable in a normal state. 50 operation rods 59
b, the communication oil passage 36 that connects the first oil chamber 29 and the second oil chamber 30 is maintained in a communication state. That is, the second spool valve 37 is urged by the discharge spring 43 in a direction to protrude from the valve body 24, whereby the second spool valve 37 is moved to the first spool valve 28.
, The concave tapered surface 35 of the first spool valve 28 and the convex tapered surface 38 of the second spool valve 37 do not come into contact with each other. For this reason, the second spool valve 37 opens the communication oil passage 36 formed in the first spool valve 28 without closing the communication oil passage 36 at the second oil chamber 30 end. Therefore, the first cylinder communicating with the cylinder chambers 15L and 15R of the power cylinder 13
The oil chamber 29 is connected to the second oil chamber 30 via the second oil chamber 30.
Is connected to the drain passage 46 communicating with the drain passage 46.

From this state, a steering torque is input to the input shaft 1 via the steering wheel (not shown), and the torsion bar 16 is twisted to rotate the input shaft 1 and the output shaft 2 relatively. , The first ring gear 55 rotates, and the operating rod 59 operates the distal end (outer peripheral surface 39) of the second spool valve 37 of one or the other control valve 20. It is pressed against the spring force to move in the axial direction.

That is, when relative rotation occurs between the input shaft 1 and the output shaft 2, the rotation amount of the first planetary gear 54 connected to the input shaft 1 and the second planetary gear 56 connected to the output shaft 2 Will be different from the rotation amount. Here, the first planetary gear 54 and the second planetary gear 56 mesh with the sun gear 53 in common, and the second ring gear 57 meshing with the second planetary gear 56 cannot rotate. Therefore, the first planetary gear 54 and the second planetary gear The difference between the rotation amount of the planetary gear 56 and the rotation amount of the first ring gear 55
Will appear. By rotating the first ring gear 55, the first ring gear 55
The operating rod 59 as a valve operating means provided in the control valve 2
0 will be manipulated.

That is, in a state where relative rotation occurs between the input shaft 1 and the output shaft 2, the operating rod 59 as valve operating means is operated in accordance with the steering torque input to the input shaft 1.
Is rotated, whereby the operating rod 59 as the valve operating means operates the control valve 20.

When the first ring gear 55 rotates, for example, counterclockwise in FIG.
The operation rod 59 provided on the control rod 5 moves upward in FIG. 2, and the side surface 59c of the distal end portion 59b of the operation rod 59 pushes the distal end portion (flat surface 39) of the second spool valve 37 of one control valve 20. . Further, the first steering operation is performed by the reverse steering operation.
When the ring gear 55 rotates clockwise in FIG.
Since the operating rod 59 moves downward in FIG. 2, the second spool valve 37 of the other control valve 20 is pressed. As a result, the second spool valve 37 of the control valve 20 is pressed by the operation rod 59, and moves in the axial direction according to the relative rotation amount between the input shaft 1 and the output shaft 2.

The operating rod 5 provided on the first ring gear 55
9 presses and moves the second spool valve 37 of the control valve 20 in the axial direction, so that the second spool valve 37
A communication oil path 36 that connects the first oil chamber 29 and the second oil chamber 30
Will be closed.

That is, the second spool valve 3 of the control valve 20
7 is moved toward the first spool valve 28 against the spring force of the discharge spring 43, so that the second spool valve 37
Is in contact with the first spool valve 28, and the concave tapered surface 35 of the first spool valve 28 and the convex tapered surface 38 of the second spool valve 37 are in contact. Therefore, the second spool valve 37 closes the communication oil passage 36 formed in the first spool valve 28 at the end on the second oil chamber 30 side, and closes the communication passage 36. Thereby, the first oil chamber 29
Is prevented from communicating with the drain passage 46 communicating with the second oil chamber 30.

Further, the operating rod 59 provided on the first ring gear 55 further presses the second spool valve 37 to move it in the axial direction, and the second spool valve 37 moves to the first spool valve 2.
8, the first spool valve 28 is pressed in the axial direction, and moves toward the first oil chamber 29 against the spring force of the supply spring 42.

When the first spool valve 28 moves toward the first oil chamber 29, the poppet portion 28a formed in the first spool valve 28 is moved to the large-diameter portion 25a and the small-diameter portion of the spool valve accommodating hole 25. The first oil chamber 29 and the third oil chamber 31 are communicated apart from the step 25c with the first oil chamber 25b. As a result, the hydraulic oil supplied from the supply passage 47 to the third oil chamber 31 is guided into the first oil chamber 29, and the first oil chamber 2
9 to the power cylinder 13. Specifically, when the operating rod 59 provided on the first ring gear 55 operates one control valve 20, the hydraulic oil guided to the first oil chamber 29 of the one control valve 20 passes through the passage 44L. The power is supplied to one cylinder chamber 15L of the power cylinder 13.
When the operating rod 59 provided on the first ring gear 55 operates the other control valve 20, the other control valve 20
The hydraulic oil guided to the first oil chamber 29 is supplied to the other cylinder chamber 15R of the power cylinder 13 via the passage 44R.

When the control valve 20 supplies hydraulic oil to the power cylinder 13, the first spool valve 28 of the control valve 20
Is the pressure between the steering torque input to the input shaft 1 and the pressure in one of the cylinder chambers 15L of the power cylinder 13 (when the steering direction is reversed, in the other cylinder chamber 15R) in the process of increasing the steering torque. When the balance between the three members and the spring force of the supply spring 42 gradually changes, the three members move and operate as follows.

That is, the poppet portion 28a of the first spool valve 28 separates from the step 25c of the spool valve accommodating hole 25, and the operating oil is supplied from the first oil chamber 29 to the power cylinder 13 and, for example, one of the cylinder chambers When the pressure in 15L increases and the steering assisting force is exerted, the steering torque input to the input shaft 1 from the steering wheel (not shown) is equal to the magnitude of the assisting force obtained by the power cylinder 13, It can be reduced. At the same time, as the pressure in the cylinder 15L increases, the pressure in the first oil chamber 29 also increases. Therefore, the first spool valve 28 is pushed back by the pressure in the first oil chamber 29, and the poppet portion 28a Contacts the step 25c of the spool valve housing hole 25 to cut off the communication between the first oil chamber 29 and the third oil chamber 31. Further, when the steering torque input to the input shaft 1 increases for the steering operation, the poppet portion 28a moves away from the step portion 25c of the spool valve housing hole 25 again, and the hydraulic oil is removed from one of the cylinders of the power cylinder 13. It is supplied to the chamber 15L. Thereafter, the above operation is repeated until a steering assisting force of a predetermined magnitude is obtained in accordance with the steering torque input to the input shaft 1.

That is, when the steering torque is input to the input shaft 1, the first spool valve 28 of the control valve 20
The poppet portion 28a separates from the step portion 25c of the spool valve housing hole 25 until the assisting force of a predetermined magnitude is obtained, and the hydraulic oil is supplied to the power cylinder 1
3 and the operation of stopping the introduction of the hydraulic oil when the poppet 28a is in contact with the step 25c of the spool valve accommodating hole 25 is repeated.

Therefore, the torsion bar 16 is
The poppet portion 28a of the first spool valve 28 is twisted only within a range until the poppet portion 28a is separated from the step portion 25c of the spool valve housing hole 25, and the relative rotation amount between the input shaft 1 and the output shaft 2 is the same. Within the range.

On the other hand, an operating rod 59 provided on the first ring gear 55 operates one of the control valves 20, and the hydraulic oil guided to the first oil chamber 29 of the one control valve 20 is supplied to the passage 44L.
Via one of the cylinder chambers 15L of the power cylinder 13
The other cylinder chamber 15R of the power cylinder 13 communicates with the first oil chamber 29 of the other control valve 20 via the passage 44R when the first oil chamber 29 is connected to the communication oil path 36 and the communication oil path 36. It communicates with the drain passage 46 via the second oil chamber 30. Further, an operating rod 59 provided on the first ring gear 55 operates the other control valve 20, and hydraulic oil is supplied from the other control valve 20 to the other cylinder chamber 15R of the power cylinder 13 via the passage 44R. In this case, the inside of one cylinder chamber 15L of the power cylinder 13 communicates with the drain passage 46 via the one control valve 20.

As a result, a force in the steering direction is applied to the rack shaft 9 via the piston 14 by the pressure of the hydraulic oil introduced into one cylinder chamber 15L or the other cylinder chamber 15R of the power cylinder 13, and The helping force is exerted.

Thus, a predetermined steering assist force is obtained by the hydraulic oil supplied to the power cylinder 13 in accordance with the steering torque applied to the input shaft 1.

Next, when the steering operation is completed and the input of the steering torque to the input shaft 1 is released, the first control valve 20 is turned off.
The spool valve 28 is pushed back toward the second oil chamber 30 by the pressure in the first oil chamber 29 and the spring force of the supply spring 42, and the poppet 28 a of the first spool valve 28 is moved to the step 25 c of the spool valve housing hole 25. The communication between the first oil chamber 29 and the third oil chamber 31 is interrupted.

The second spool valve 37 controls the pressure in the second oil chamber 30 (this pressure is equal to the cylinder chamber of the power cylinder 13 to which the hydraulic oil is supplied, for example, one of the cylinder chambers 1).
5L) and the spring force of the discharge spring 43, which is gradually pushed back in the direction away from the first spool valve 28, and the concave tapered surface 35 of the first spool valve 28 and the convexity of the second spool valve 37. The state is such that the tapered surface 38 of the shape does not contact. For this reason, the second spool valve 37 opens a communication oil passage 36 formed in the first spool valve 28 at an end on the second oil chamber 30 side, and the communication oil passage 36
open. Thereby, one cylinder chamber 15L (or the other cylinder chamber 15R) of the power cylinder 13 is provided.
The first oil chamber 29 communicates with the drain passage 46 to release the inside of the cylinder chamber 15L (or the cylinder chamber 15R) under atmospheric pressure, thereby removing the steering assisting force.

At this time, the second spool valve 37 of the control valve 20 is connected to the steering torque remaining on the input shaft 1 in the process of decreasing the steering torque and the inside of one cylinder chamber 15L of the power cylinder 13 (the steering direction is reversed). In the case of (3), the pressure remaining in the other cylinder chamber 15R) and the discharge spring 43
When the balance between the three members and the spring force gradually changes, the spring moves and the communication oil passage 36 is gradually opened.

That is, when the second spool valve 37 slightly opens the communication oil passage 36, the oil pressure in one cylinder chamber 15L of the power cylinder 13 is slightly reduced, and the steering assisting force is reduced. When the assisting force of the power cylinder 13 is reduced, the steering torque remaining on the input shaft 1 is superior, and the second
The spool valve 37 contacts the first spool valve 28 and closes the communication oil passage 36. Further, when the steering torque input to the input shaft 1 is removed to cancel the steering operation, the second spool valve 37 separates from the first spool valve 28 again to open the communication oil passage 36, and the power The hydraulic oil in one cylinder chamber 15L of the cylinder 13 is released to the drain passage 46. Thereafter, the above operation is repeated until the steering torque input to the input shaft 1 and the steering assisting force of the power cylinder 13 become zero.

In other words, the second spool valve 37 of the control valve 20 reduces the relative rotation between the input shaft 1 and the output shaft 2 by reducing the steering torque input to the input shaft 1, thereby reducing the steering assist. Until the power becomes zero, the first spool valve 28
From the power cylinder 13
The operation of communicating the oil passage with the drain passage 46 and the operation of contacting the first spool valve 28 and closing the communication oil passage 36 are repeated.

As a result, a steering assisting force by the power cylinder 13 is obtained for a leftward or rightward steering operation of the steering mechanism.

When the operating oil is supplied to the power cylinder 13 via the control valve 20, the cutoff valve 81 operates as follows. That is, the cutoff valve 81 is connected to the passage 4
The operation is controlled based on the hydraulic pressure of the first oil chamber 29 of the control valve 20 guided through the 4L (or 44R), and the plunger 84 of the cutoff valve 81 operates the operating rod 59 provided on the first ring gear 55. I do.

That is, the pressure chamber 8 of the cutoff valve 81
5 has a control valve 2 via a passage 44L (or 44R).
0, the hydraulic pressure in the first oil chamber 29 is guided, the control valve 20 is operated by the operating rod 59 provided on the first ring gear 55, and the oil pressure in the first oil chamber 29 rises.
The plunger 84 protrudes into the through hole 40 due to the balance between the pressure in the pressure chamber 85 and the spring member 87, and after a predetermined stroke due to a gap between the tip of the plunger 84 and the operation rod 59, the operation rod of the conversion mechanism 50 Pressing 59,
The operating rod 59 of the conversion mechanism 50 gives an assisting force to the force of pressing the second spool valve 37 of the control valve 20 against the spring force of the discharge spring 43.

For this reason, when the steering torque is input to the input shaft 1 and the operating rod 59 provided on the first ring gear 55 operates the control valve 20 to increase the oil pressure in the first oil chamber 29, After the cutoff point at which the first oil chamber 29 of the control valve 20 has increased to a predetermined pressure, the steering assisting force is controlled with a characteristic (cutoff characteristic) in which the rate of increase of the hydraulic pressure with respect to the steering torque increases.

Here, the control valve 20, which controls the supply of hydraulic oil to the power cylinder, is directly operated by an operating rod 59, which is provided on the first ring gear 55 of the first planetary gear unit 51. As a result, sliding resistance and the like are reduced as much as possible, and smooth operation is achieved.

Therefore, a power steering device capable of obtaining an excellent steering feeling can be obtained.

The operation rod 59 as the valve operation means is provided.
Is mounted on the first ring gear 55, so that the operation rod 59 can be mounted after the first ring gear 55 is mounted in the housing 3, thereby facilitating the mounting operation.

Further, by providing the thrust bearing 65 as the filling member, the first ring gear 55 provided with the operating rod 59 as the valve operating means and the housing 3 are provided.
(3a) can be reduced, and the rotational resistance of the first ring gear 55 can be reduced.
The smooth rotation of the ring gear 55 is achieved.

According to the fifth aspect of the present invention, the second ring gear 57 is provided at the neutral position in the rotational direction by providing the bolt 63 as gear operating means capable of operating the second ring gear 57 from the outside. Alignment becomes easier.

Further, since the control valve 20 is arranged substantially parallel to the input shaft 1, the projecting portion outward in the radial direction is reduced as compared with the case where the control valve 20 is arranged in a substantially right angle direction. The size of the entire device can be reduced.

Further, by providing the cutoff valve 81, it is possible to impart a cutoff characteristic to the characteristic of the steering assist force.

The cutoff valve 81 is connected to the control valve 20.
Are arranged in parallel with each other, so that the number of protrusions outward in the radial direction can be reduced, and the size of the entire apparatus can be reduced.

Although the embodiments have been described with reference to the drawings, the specific configuration is not limited to these embodiments, and can be changed without departing from the spirit of the invention. For example, the embodiment in which the first ring gear 55 is provided with the operating rod 59 as a valve operating means and the second ring gear 57 is made unrotatable has been described.
5 may not be rotatable, and the second ring gear 57 may be provided with an operating rod 59 as a valve operating means. In this case, the thrust bearing 65 as the closing member is disposed between the second ring gear 57 and the housing 3.

The first ring gear 55 or the second ring gear 55
An operating rod 59 as a valve operating means provided on the ring gear 57
May be provided corresponding to the control valve 20 and the cutoff valve 81, respectively.

The first spool valve 2 of the control valve 20
Although the embodiment in which the communication oil passage 36 is formed in FIG. 8 has been described, the communication oil passage 36 may be provided in the body 24.

[0101]

As described above in detail, according to the present invention, a power steering device capable of obtaining an excellent steering feeling can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a power steering device showing an embodiment of the present invention.

FIG. 2 is an explanatory view including a cross-sectional view taken along the line AA of FIG. 1;

FIG. 3 is an enlarged sectional view taken along the line AA of FIG. 2;

FIG. 4 is a sectional view taken along line BB of FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 input shaft 2 output shaft 13 power cylinder 20 control valve 51 first planetary gear device 52 second planetary gear device 53 sun gear 54 first planetary gear 55 first ring gear 56 second planetary gear 57 second ring gear 59 operating rod (valve operating means)

Claims (5)

[Claims] 1. A power steering apparatus for supplying and discharging hydraulic oil to and from a power cylinder in accordance with a steering torque input to an input shaft of a steering mechanism to obtain a steering assisting force. And an output shaft that is connected to the input shaft so as to be relatively rotatable and that transmits a steering torque from the input shaft.A sun gear is shared between the input shaft and the output shaft. A first planetary gear device having a first ring gear provided on the outer periphery of the sun gear via a first planetary gear, and a second planetary gear device on the outer periphery of the sun gear.
A second planetary gear device provided with a second ring gear via a planetary gear is provided, the first planetary gear is connected to an input shaft, the second planetary gear is connected to an output shaft, and the first ring gear and the second ring gear are connected to each other. One of the non-rotatable, provided with a valve operating means on the other,
A power steering device characterized in that a control valve can be operated by the valve operating means. 2. The first planetary gear device and the second planetary gear device are housed in a housing, and the valve operating means is a first planetary gear device.
Attached to the ring gear or the second ring gear,
The power steering apparatus according to claim 1, wherein the valve operating means extends through the housing. 3. The first planetary gear device and the second planetary gear device are housed in a housing, and an axial gap is provided between the housing and a first ring gear or a second ring gear provided with the valve operating means. 2. The power steering device according to claim 1, further comprising a filling member for filling. 4. The power steering device according to claim 3, wherein the filling member is a thrust bearing. 5. The first planetary gear device and the second planetary gear device are housed in a housing, and the housing is in contact with an outer periphery of the first or second ring gear that is not rotatable. 2. The power steering apparatus according to claim 1, further comprising gear operating means capable of externally rotating the gear.