JPH11310142A - Structure and method for coupling input shaft to torsion bar in power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To couple an input shaft rigidly to a torsion bar in a vehicle power steering device by eliminating performance instability, and simplifying a structure and method for coupling the input shaft to the torsion bar. SOLUTION: This coupling structure has a torsion bar 5 passed inside a cylindrical input shaft 3 and couples the input shaft 3 to the torsion bar 5 by coupling the upper end of the torsion bar 5 to the upper end of the input shaft 3 and coupling the lower end of the torsion bar 5 to the upper end of an output shaft 4 in a power steering device 1 in which the shafts 3, 4 are coupled together via the torsion bar 5. In this case, a hole 6 is bored in the upper end of the torsion bar 5 along the direction of its axis and a press fit member (steel ball or columnar body) 7 is press fitted into the hole 6 up to the depth exceeding the upper end face 3a of the input shaft 3 and the part of the input shaft 3 from the press fit member 7 to the upper end face 32a is radially caulked to lock the press fit member 7 in place. Caulking operations are performed on the bottoms of two pin grooves 3b, 3b formed in the outer peripheral surface of the upper end of the input shaft 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coupling structure and a coupling method between an input shaft and a torsion bar in a power steering device for a vehicle.

[0002]

2. Description of the Related Art Conventionally, a torsion bar is inserted into a cylindrical input shaft, an upper end of the torsion bar is connected to an upper end of the input shaft, and a lower end of the torsion bar is connected to an upper end of the output shaft. As a method of connecting the input shaft and the torsion bar in the power steering device in which these two shafts are connected via the torsion bar, as shown in FIG. 5, the upper end of the output shaft (not shown) Press-fit the lower end of the torsion bar 05 into the hole formed in the part, and fix it.
Next, the input shaft 03 is fitted to the torsion bar 05, the input shaft 03 and the output shaft are neutralized, and the holes 03c and 05b are simultaneously formed in the input shaft 03 and the torsion bar 05. (Refer to FIG. 5B.) These holes 03c and 05b
5A is pressed into the pin 016 shown in FIG.
As shown in (c), a method of pin-connecting both of these was common.

[0003]

However, according to this method, chips are generated when the input shaft 03 and the torsion bar 05 are simultaneously drilled, and the chips are generated in the gear box or the sensor box of the power steering device. In some cases, and may stick to these internal seal portions, causing a problem in performance.

When the pin 016 is press-fitted into the holes 03c and 05b simultaneously opened in the input shaft 03 and the torsion bar 05, the input shaft 03 and the torsion bar are urged by the circumferential component of the lateral load caused by the press-fitting. The relative positional relationship between the bar 05 and the bar 05 in the circumferential direction may be deviated, and the neutralization of the input shaft 03 and the output shaft may be broken, resulting in unstable performance.

Further, a joint member for connecting the input shaft and the torsion bar requires a fail-safe mechanism for preventing the pin 016 from coming off, and the structure is complicated.

According to the present invention, a torsion bar is inserted into a cylindrical input shaft, an upper end of the torsion bar is connected to an upper end of the input shaft, and a lower end of the torsion bar is connected to an upper end of an output shaft. In the power steering apparatus in which these two shafts are connected via the torsion bar, the input shaft and the torsion bar are connected to each other by a structure and a method for solving the above-described problem. It is an object of the present invention to provide a coupling structure and a coupling method between an input shaft and a torsion bar in a power steering device capable of firmly coupling an input shaft and a torsion bar.

[0007]

The present invention relates to a coupling structure and a coupling method between an input shaft and a torsion bar in a power steering apparatus which has solved the above-mentioned problems, and is described in claim 1. The invention
A torsion bar is inserted inside the cylindrical input shaft, and an upper end of the torsion bar is coupled to an upper end of the input shaft,
A lower end of the torsion bar is connected to an upper end of the output shaft, and the two shafts are connected via the torsion bar. In the part, a hole is drilled along the axial direction of the torsion bar,
The press-fitting member is press-fitted into the hole to a depth exceeding the upper end face of the input shaft, and a portion of the input shaft closer to the upper end face than the press-fitting member is radially caulked, so that the press-fitting member comes off. A coupling structure of an input shaft and a torsion bar in a power steering device characterized by being stopped.

[0008] Since the invention described in claim 1 is configured as described above, the coupling structure between the input shaft and the torsion bar is provided at the upper end of the torsion bar along the axial direction of the torsion bar. A hole is drilled, and the press-fitting member is pressed into the hole to a depth exceeding the upper end surface of the input shaft, and a portion of the input shaft closer to the upper end surface than the press-fitting member is radially caulked,
It is configured by preventing the press-fitting member from coming off.

As a result, when connecting the input shaft and the torsion bar, the use of the connecting pin is eliminated, and it becomes unnecessary to make a hole for the connecting pin on the input shaft and the torsion bar. The performance defect caused by the occurrence is eliminated.

In addition, since the use of the connecting pin is eliminated,
There is no danger that the neutralization of the input shaft and the output shaft will be lost, and it will be easy to firmly couple the input shaft and the torsion bar while maintaining the neutralization. The fear of stability is eliminated.

The coupling structure between the input shaft and the torsion bar includes a hole formed at the upper end of the torsion bar, a press-fit member press-fit into the hole, and an input shaft for preventing the press-fit member from coming off. It is only constituted by swaging (and thus also of the bore wall), and the mechanism for fail-safe is no longer required, so that its construction is very simple.

Furthermore, the portion of the input shaft closer to the upper end surface than the press-fitting member is radially swaged to prevent the press-fitting member from coming out of the hole, so that the connection between the input shaft and the torsion bar is securely and firmly made. Can be maintained.

According to the second aspect of the present invention, since the press-fitting member is made of a steel ball, the press-fitting and crimping work can be easily performed.

According to the third aspect of the present invention, since the press-fitting member is formed of a cylindrical body, the outer peripheral surface of the upper end of the torsion bar is formed by press-fitting the cylindrical body. The contact area between the input shaft and the inner peripheral surface of the upper end of the input shaft can be widened, and the input shaft and the torsion bar can be connected sufficiently firmly.

Further, according to the fourth aspect of the present invention, in the caulking processing, the steering wheel shaft is non-rotatably connected to the input shaft in the caulking process. Therefore, the input shaft is formed on the outer peripheral surface of the upper end portion of the input shaft at the bottom of the two pin grooves formed in parallel with the axial direction at right angles to each other, so that the existing structure can be used. Since the structural part is thinner than the other parts, the processing operation is easy.

Further, the invention described in claim 5 is:
A torsion bar is inserted inside the cylindrical input shaft, and an upper end of the torsion bar is coupled to an upper end of the input shaft,
The lower end of the torsion bar is connected to the upper end of the output shaft, and the two ends of the torsion bar are connected via the torsion bar. A hole is formed in the portion along the axial direction of the torsion bar, and after the input shaft and the output shaft are neutralized, a press-fit member is inserted into the hole of the torsion bar, and the input shaft is Press-fitted to a depth exceeding the upper end face of the input shaft, and then radially caulking a portion of the input shaft closer to the upper end face than the press-fitted member to prevent the press-fitted member from coming off. And Fig. 6 is a method for connecting an input shaft and a torsion bar in a power steering device.

According to the fifth aspect of the present invention, since the input shaft and the torsion bar are connected to each other by a method of connecting the input shaft to the torsion bar in advance along the axial direction of the torsion bar. After the hole is bored and the input shaft and the output shaft are neutralized, the press-fitting member is pressed into the hole of the torsion bar to a depth exceeding the upper end surface of the input shaft,
Then, the portion of the input shaft closer to the upper end surface than the press-fitting member is radially swaged to prevent the press-fitting member from coming off.

As a result, the coupling structure between the input shaft and the torsion bar in the power steering apparatus according to the first aspect of the present invention having various effects as described above can be obtained by a very simple method.

According to the sixth aspect of the present invention, the caulking process is performed so that the steering wheel shaft is non-rotatably connected to the input shaft.
The input shaft is formed on the bottom of two pin grooves formed in parallel to the axial direction at right angles to the outer peripheral surface of the upper end of the input shaft, so that the existing structure can be used. ,
Since it is thinner than the other parts, its working is easy.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the first, second, fourth and sixth aspects of the present invention shown in FIGS. 1 and 3 will be described.
An embodiment (Embodiment 1) of the invention described in (1) will be described. FIG. 1 is a partial longitudinal sectional side view of a power steering device to which a coupling structure and a coupling method of an input shaft and a torsion bar according to a first embodiment are applied. FIGS. It is a figure which shows each one process of the operation | work which couple | bonds a shaft and a torsion bar.

In FIG. 1, a power steering device 1 to which a coupling structure and a coupling method of an input shaft 3 and a torsion bar 5 according to a first embodiment are applied is an electric power steering device, and a steering wheel (not shown) is used. The input shaft 3 is connected to an upper end (upper end) in FIG.

The connection between the steering wheel and the input shaft 3 is not shown in detail, but the lower end of the steering wheel shaft is fitted to the upper end of the input shaft 3 and then
This is performed by driving two pins in parallel between them. Thus, the steering wheel and the input shaft 3 are connected to each other so as not to rotate.

The two pins are formed on the outer peripheral surface of the upper end of the input shaft 3 along two pin grooves 3b, 3b formed parallel to and perpendicular to the axial direction of the input shaft 3. Thus, it is driven between the lower end of the steering wheel shaft and the upper end of the input shaft 3.

The input shaft 3 is an elongated cylindrical hollow shaft into which a torsion bar 5 is inserted. The torsion bar 5 is bored in the upper end portion in the axial direction as described later. When the steel ball 7 is press-fitted into the hole 6, the upper end thereof is connected to the upper end of the input shaft 3, and the lower end thereof is formed in a press-fit hole 8 formed in the upper end of the pinion shaft 4 which is the output shaft. And press fit into it. And, in this way, these two shafts 3, 4 are
They are connected via a torsion bar 5.

The lower end of the input shaft 3 is inserted into a fitting hole 9 formed at the upper end of the pinion shaft 4 and is rotatably held therein.
It is rotatably supported by a bearing 10 in an upper part of the inside of the sensor housing 2 composed of the divided body. The bottom surface 11 of the fitting hole 9 forms a surface on which the press-fit hole 8 is formed.

The upper end of the pinion shaft 4 is rotatably positioned in the axial direction by a bearing 12 and supported by a bearing 12 at a lower portion in the view of the inside of the sensor box 2.
Is meshed with a rack (not shown), and further interlocked with the wheels via a link mechanism.

A core is provided between the input shaft 3 and the pinion shaft 4.
The core 13 detects a relative rotation amount difference (torsion amount) between the input shaft 3 and the pinion shaft 4 based on a torque acting on the input shaft 3 and the pinion shaft 4 as an axial movement amount. Then, based on the detected value, a steering assist force necessary to eliminate the relative rotation amount difference is applied to the output shaft side after the pinion shaft 4 to rotate the wheel corresponding to the steering assist force. The rudder is steered to provide a light feeling of steering. Reference numeral 14 denotes the amount of axial movement of the core 13 as an electric signal,
A coil that detects the direction of the movement.

Next, a connection structure and a connection method between the input shaft 3 and the torsion bar 5 in the first embodiment will be described. As shown in FIGS. 1 to 3, a hole 6 having a predetermined depth is formed in the upper end portion of the torsion bar 5 in the axial direction from the end face side in advance.

Before the steel ball 7 is pressed into the hole 6, the input shaft 3 and the pinion shaft 4
It is relatively freely rotatable. Therefore, in this state, the input shaft 3 and the pinion shaft 4 are neutralized to perform temporary assembly.

Next, as shown in FIG. 2, a steel ball 7 is press-fitted into a hole 6 at the upper end of the torsion bar 5, and the diameter of the hole wall 5a of the hole 6 is increased. ,
In particular, the outer peripheral surface of the portion of the steel ball 7 bulged by the spherical surface is pressed against the inner peripheral surface of the upper end of the input shaft 3. Thereby, the upper end of the input shaft 3 and the upper end of the torsion bar 5 are firmly connected, and the input shaft 3 does not come off from the torsion bar 5 (see FIG. 3).

Next, in the state shown in FIG. 3, the portion of the input shaft 3 on the upper end face 3a side from the position where the steel ball 7 is press-fitted is radially swaged as indicated by the arrow, and the hole 6 of the steel ball 7 is formed. To keep from falling off.

The caulking process is performed so that two pin grooves 3b, 3b formed on the outer peripheral surface of the upper end of the input shaft 3, are provided at two central positions in the longitudinal direction of the groove bottoms. It is convenient to do so. In this way, the thickness of this portion of the pin groove 3b is smaller than that of the other portions, so that the working operation becomes easier. In this caulking process, the hole wall 5a of the hole 6 at the upper end of the torsion bar 5 is also caulked together.

Since the first embodiment is configured as described above, the following effects can be obtained. The coupling structure of the input shaft 3 and the torsion bar 5 is such that a hole 6 is drilled at the upper end of the torsion bar 5 along the axial direction of the torsion bar 5, and a steel ball 7 is pressed into the hole 6 and The pin grooves 3b, 3b on the upper end surface 3a side of the shaft 3 where the steel ball 7 is press-fitted are crimped in the radial direction to prevent the steel ball 7 from coming off.

As a result, when the input shaft 3 and the torsion bar 5 are connected to each other, the connecting pin is not used as in the prior art, and the input shaft 3 and the torsion bar 5 are provided with holes for the connecting pin. This eliminates the need to perform the process, thereby eliminating performance defects caused by the generation of chips.

Further, since the use of the connecting pin is eliminated,
There is no danger that the neutralization of the input shaft 3 and the output shaft (pinion shaft) 4 will be broken, and it is easy to firmly couple the input shaft 3 and the torsion bar 5 while maintaining the neutralization.
The possibility of performance instability due to collapse of the neutralization is eliminated.

The coupling structure between the input shaft 3 and the torsion bar 5 is formed by a hole 6 formed at the upper end of the torsion bar 5.
And a steel ball 7 press-fitted into the hole 6 and a caulking for preventing the steel ball 7 from coming off, and a mechanism for fail-safe is not required. Becomes very simple.

Further, the pin grooves 3b, 3b located on the upper end face 3a side from the position where the steel ball 7 of the input shaft 3 is press-fitted.
The bottom of the groove is swaged to prevent the steel ball 7 from coming out of the hole 6, so that the connection between the input shaft 3 and the torsion bar 5 can be securely and firmly maintained.

Further, since the steel ball 7 is press-fitted, the press-fitting and crimping work are extremely easy. In particular, caulking is performed by the two pin grooves 3b at the upper end of the input shaft 3,
3b is applied to the center in the longitudinal direction by using the groove bottom portion, so that the thin portion of the input shaft 3 can be used, and it can be performed without relatively high accuracy. Work is extremely easy.

A method of connecting the input shaft 3 and the torsion bar 5 is such that a hole 6 is formed in the upper end of the torsion bar 5 in advance in the axial direction, and the input shaft 3 and the output shaft 4 are neutralized. Then, the steel ball 7 is press-fitted into the hole 6 of the torsion bar 5, and then the pin groove 3 on the upper end face 3a side of the input shaft 3 where the steel ball 7 is press-fitted.
b, 3b by radially tightening the bottom of the groove, steel ball 7
This is done by retaining As a result, it is possible to obtain a coupling structure between the input shaft 3 and the torsion bar 5 having various effects as described above by a very simple method.

Next, an embodiment (Embodiment 2) of the invention described in claim 3 of the present application shown in FIG. 4 will be described. The second embodiment differs from the first embodiment only in the configuration of the press-fit member. That is, in the first embodiment, the steel ball 7 is used as the press-fitting member, but in the second embodiment, as shown in FIG. 5, a cylindrical body 15 is used.

The cylindrical body 15 is provided with the hole 6 of the torsion bar 5.
Having a length that is considerably shorter than the depth of the input shaft 3, and having a diameter slightly larger than the depth thereof, and being pressed into the hole 6 deeper than the position of the pin grooves 3b of the input shaft 3 and the groove bottom of the 3b. As a result, the diameter of the hole wall 5a of the hole 6 is increased, and the outer peripheral surface of the hole wall 5a is pressed against the inner peripheral surface of the upper end of the input shaft 3.

The bottoms of the pin grooves 3b, 3b on the upper end surface 3a side of the position where the cylindrical body 15 of the input shaft 3 is pressed into the hole 6 are caulked to prevent the cylindrical body 15 from falling out of the hole 6. Is performed in the same manner as in the first embodiment.

In the second embodiment, the contact area between the outer peripheral surface of the upper end of the torsion bar 5 and the inner peripheral surface of the upper end of the input shaft 3 is reduced by press-fitting the cylindrical body. The input shaft 3 and the torsion bar 5 can be connected sufficiently firmly.

In the first and second embodiments, the power steering device is an electric power steering device. However, the power steering device is not limited to this, and may be a hydraulic power steering device.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment (embodiment 1) of the present invention described in claims 1, 2, 4 and 6 of the present application; FIG. 4 is a partial vertical cross-sectional side view of the completed power steering device.

FIG. 2 is a view showing one step of an operation of connecting an input shaft and a torsion bar in the first embodiment of FIG. 1;

FIG. 3 is a view showing another one of the steps.

FIG. 4 is a view corresponding to FIG. 3, showing one step of an operation for obtaining a coupling structure between an input shaft and a torsion bar in one embodiment (Embodiment 2) of the invention described in claim 3 of the present application; It is.

FIG. 5 is a diagram showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1: Power steering device, 2: Sensor box, 3
... input shaft, 3a ... upper end surface, 3b ... pin groove, 4 ... pinion shaft (output shaft), 4a ... pinion, 5 ... torsion bar,
5a ... hole wall, 6 ... hole, 7 ... steel ball, 8 ... press-fit hole, 9 ... fitting hole, 10 ... bearing, 11 ... bottom surface, 12 ... bearing, 13 ...
Core, 14 ... coil, 15 ... cylindrical body.

Claims (6)

[Claims] 1. A torsion bar is inserted into a cylindrical input shaft, an upper end of the torsion bar is connected to an upper end of the input shaft, and a lower end of the torsion bar is connected to an upper end of the output shaft. In the coupling structure of the input shaft and the torsion bar in the power steering device in which these two shafts are connected via the torsion bar, a hole is formed in the upper end of the torsion bar along the axial direction of the torsion bar. The press-fit member is press-fitted into the hole to a depth exceeding the upper end face of the input shaft, and a portion of the input shaft closer to the upper end face than the press-fit member is radially caulked, and the press-fit member is pressed. A coupling structure of an input shaft and a torsion bar in a power steering device, wherein the torsion bar is prevented from coming off. 2. The structure according to claim 1, wherein the press-fitting member is a steel ball. 3. The coupling structure of an input shaft and a torsion bar according to claim 1, wherein the press-fitting member is a cylindrical body. 4. The caulking process is performed in such a manner that a steering wheel shaft is non-rotatably connected to the input shaft. The coupling structure of an input shaft and a torsion bar in a power steering device according to any one of claims 1 to 3, wherein the coupling shaft is provided on a groove bottom of each of the pin grooves. 5. A torsion bar is inserted into a cylindrical input shaft, an upper end of the torsion bar is connected to an upper end of the input shaft, and a lower end of the torsion bar is connected to an upper end of the output shaft. In a method of coupling an input shaft and a torsion bar in a power steering device in which these two shafts are connected via the torsion bar, a hole is formed in an upper end portion of the torsion bar in advance along an axial direction of the torsion bar. In addition, after neutralizing the input shaft and the output shaft, a press-fitting member is press-fitted into the hole of the torsion bar to a depth exceeding an upper end surface of the input shaft. A portion of the input shaft closer to the upper end face side than the press-fitting member is radially swaged to prevent the press-fitting member from coming off, so that the input shaft and the torsion in the power steering apparatus are characterized. How to connect with the option bar. 6. The crimping process is performed in such a manner that a steering wheel shaft is non-rotatably connected to the input shaft, and is formed on an outer peripheral surface of an upper end portion of the input shaft so as to be orthogonal to and parallel to an axial direction. 6. The coupling structure of an input shaft and a torsion bar in a power steering device according to claim 5, wherein the input shaft and the torsion bar are provided on the groove bottoms of the pin grooves of the strip.