JPH0634027A - Friction transmission with torque detecting function - Google Patents

Abstract

PURPOSE:To protect a transmission system by always monitoring load torque off the transmission system by the use of a simple means, and cutting of transmission when the load torque becomes excessive. CONSTITUTION:A friction transmission is disposed on the way of a transmission system from a prime mover to rotary equipment on a driven side. Load torque is determined on the basis of a slip ratio by the use of such a property of the friction transmission that the slip ratio is varied according to the load torque. The slip ratio is calculated based on the revolution speeds before and after the friction transmission, which are detected by sensors. If the load torque exceeds a predetermined value, a speed change ratio of a speed changing device provided in the transmission system is set to zero. The friction transmission 37 with a torque detecting function is constituted, inside a pulley 1, of a friction surface 5, a planet roller 6, a driven roller 7, and a holding device 8. A pin 12 is adapted to idly rotate the holding device 8 after being sheared in the case where an excessive load torque acts so as to cut off transmission, and it serves as a safety device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction transmission device having a load torque detecting function, which is suitable for use in a transmission system when a refrigerant compressor of an air conditioner is driven by an automobile engine, for example.

[0002]

2. Description of the Related Art For example, in a friction type continuously variable transmission described in Japanese Patent Laid-Open No. 61-189358, the output can be obtained by adjusting the gear ratio to zero even when the input shaft is rotating. When a transmission having a function of stopping the shaft is used to drive a rotating device such as a refrigerant compressor in an air conditioner for an automobile, a prime mover such as an automobile engine is used. Since it is not necessary to provide a clutch for connecting and disconnecting the power transmission from the engine, the output shaft of the prime mover is directly connected to the input shaft of the transmission, and the output shaft of the transmission is directly connected to the input shaft of the compressor.

Further, in a refrigerant compressor in an air conditioner for an automobile, the compressor itself is of a variable discharge capacity type,
As long as the discharge capacity of the refrigerant can be reduced to zero, it is not necessary to provide a drive shaft of the compressor with, for example, a transmission or an electromagnetic clutch. Therefore, a refrigerant compressor that is an automobile engine and a rotating device. It will be used by directly connecting and with something like a transmission belt. A compressor directly connected to the prime mover without interposing a clutch is called a clutchless compressor.

[0004]

As described above, in a transmission system in which a prime mover is directly connected to a rotating device such as a transmission or a refrigerant compressor without a clutch, a transmission, a compressor, etc. Even if the rotating equipment on the driven side of is overloaded due to some cause, or should it lock up, the transmission system does not have a clutch to stop power transmission, so for example, belt breakage or friction type As with the galling of the friction engagement surface of the continuously variable transmission, a portion of the transmission system having a relatively low strength will be damaged.

In order to deal with this problem, a clutch is provided in the transmission system, and some detection device having a function of constantly monitoring the load torque is provided so that when the load torque reaches an excessive value, the transmission is It is conceivable to perform control such that the gear ratio is zero, but it is not easy to detect the load torque in real time, and by adding devices and clutches for that, the configuration of the transmission system generally becomes complicated, Alternatively, the size is often increased and the cost is significantly increased.

In view of the above problems in the prior art, the present invention detects the load torque in the transmission system in real time with a relatively simple structure and immediately stops the transmission when the load torque increases to an excessive value. It is an object of the present invention to provide a new means capable of performing the above. It is another object of the present invention to provide a novel means in which the load torque detecting means itself has a means for cutting off transmission when the load torque reaches an excessive value. It is a thing.

[0007]

The present invention provides, as a first means for achieving the above object, a friction transmission inserted in the middle of a series of transmission systems from a prime mover to a driven side rotating device. Device, an input rotation speed detection sensor for detecting a rotation speed on the drive side of the friction transmission, an output rotation speed detection sensor for similarly detecting a rotation speed on the driven side, the input rotation speed detection sensor and the output rotation Calculation means for calculating the slip ratio of the friction transmission from the detection value of the number detection sensor, and further for calculating the load torque of the friction transmission from the slip ratio, and the calculation means for indicating the generation of the load torque of a predetermined value or more. Provided is a friction transmission device with a torque detection function, comprising: a control unit that activates a unit that can reduce a load torque when a signal is output.

According to the present invention, as a second means for achieving the above object, a friction transmission consisting of a planetary roller transmission mechanism inserted in the middle of a series of transmission systems from a prime mover to a driven rotating machine. Device, an input rotation speed detection sensor for detecting a rotation speed on the drive side of the friction transmission, an output rotation speed detection sensor for similarly detecting a rotation speed on the driven side, the input rotation speed detection sensor and the output rotation Calculation means for calculating the slip ratio of the friction transmission from the detection value of the number detection sensor, and further for calculating the load torque of the friction transmission from the slip ratio, and the calculation means for indicating the generation of the load torque of a predetermined value or more. A planetary roller of the planetary roller transmission mechanism in a normal state, and a control means for activating a means for reducing a load torque when a signal is output. Means provided for preventing rotation of the cage that supports and provides the torque detection function friction drive apparatus, characterized in that it also serves as a safety device of the drive system.

[0009]

In the first solution of the present invention, the rotation of the prime mover is transmitted to the driven-side rotating equipment via the friction transmission. Since the friction transmission generally has a property of causing a slip having a magnitude related to the magnitude of the load torque, a slip is generated from the input rotation speed and the output rotation speed detected by the input rotation speed detection sensor and the output rotation speed detection sensor by the calculation means. By calculating the rate, the magnitude of the load torque can be detected by comparing the known relationship between the load torque and the slip rate. When the value of the load torque thus detected exceeds a predetermined value, the control means is activated to interrupt the transmission of the torque to stop the rotation on the driven side or reduce the rotation speed to reduce the load. Reduce torque and avoid transmission system damage.

In a second solution means of the present invention, the friction transmission device in the first solution means is constituted by a planetary roller transmission mechanism, and further, a holding device which supports a planetary roller of the planetary roller transmission mechanism is provided. In addition to the same operation as the first solution means, the magnitude of the load torque exceeds the predetermined value, because the means provided for preventing the rotation of the device also serves as the safety device of the transmission system. At this time, the safety device operates to release the restraint of the cage supporting the planetary roller, so that the planetary roller can freely revolve and the rotation of the driving side is not transmitted to the driven side. Therefore, the safety of the transmission system is ensured as a backup device when the activation of the control means is delayed or the input / output rotation speed detection sensor, the arithmetic means, the control means, etc. are broken.

[0011]

1 shows an embodiment of a friction transmission device with a torque detecting function according to the present invention. The pulley 1 is rotatably supported via a bearing 3 at the tip of a boss portion 2 provided in a housing of a rotating device (not shown) driven by the pulley 1. Inside the pulley 1, a cylindrical friction surface 5 formed on the inner surface of the pulley inner boss 4, a plurality of planetary rollers 6 inscribed in the friction surface 5 and rolling in the circumferential direction, and a central portion There is one driven roller 7 in contact with all the planetary rollers 6. In the illustrated embodiment, the friction surface 5, the planetary roller 6, and the driven roller 7 all have a cylindrical friction engagement surface. However, as a modification thereof, all the friction engagement surfaces are formed into a conical shape or a shape close thereto. Further, by making it possible to adjust the thrust force that pushes the planetary roller 6 in the axial direction with a screw, a spring, or the like, it is possible to generate an appropriate frictional pressure contact force between the frictional engagement surfaces.

All the planetary rollers 6 are rotatably supported on a plurality of roller shafts 9 provided on a common cage 8. The retainer 8 itself is rotatable on the axis of a drive shaft 10 of a rotating device which is integrated with the driven roller 7, and the above-mentioned parts constitute a friction type planetary roller transmission mechanism 11. There is. All friction transmission surfaces of the planetary roller transmission mechanism 11 are lubricated with grease. In some cases, the planetary roller transmission mechanism 11
May be a closed type, and an appropriate amount of liquid lubricating oil may be filled in the inside so that frictional transmission is performed while the frictional engagement surface is lubricated and cooled by the lubricating oil.

In the friction transmission device 37 with a torque detection function shown in FIG. 1, the planetary roller transmission mechanism 11 is provided in order to block transmission of excessive torque through the friction transmission device 11.
It also has a safety device as part of it. That is, the safety device is configured by inserting the pin 12 inserted into the hole of the fixed boss portion 2 into the hole formed in the retainer 8. In a normal transmission state where the load torque is within a predetermined value, the pin 12 blocks the rotation of the retainer 8, so that the planetary roller 6 does not revolve and stays at a fixed position and rotates. Thus, the rotation of the friction surface 5 of the pulley 1 can be transmitted to the driven roller 7.

When the pulley 1 is rotatably driven by a belt (not shown) wound around it, frictional transmission between the boss 4 inside the pulley of the planetary roller transmission mechanism 11 and the planetary roller 6, and further between the planetary roller 6 and the driven roller 7. As a result, the planetary roller 6 rotates and the drive shaft 10 is accelerated at a constant rate. At this time, the rotation speed (input rotation speed) of the pulley 1 is set to N
and _in, the rotational speed of the drive shaft 10 (output rotational speed) N _out,
If the speed increasing ratio is ε, there is a relationship of N _out = ε · N _in. However, when a load acts, some friction always occurs on the friction engagement surface as in the friction transmission mechanism. , N _out <ε · N _in . Therefore, if the true output speed is N _out ^' ,
The slip ratio S is expressed as S = (ε · N _in −N _out ^′ ) / ε · N _in (1). Since the slip ratio S and the load torque T have a relationship as shown in FIG. 2, for example, the input speed N _in
Is detected by a rotation speed sensor (not shown) provided in the rotating portion of the pulley 1 or before, and the output rotation speed N
_The slip ratio S can be detected in real time by comparing the map as shown in FIG. 2 by detecting ^" _out ^'" by a rotation speed sensor (not shown) provided in the rotating portion after the driven roller 7.

Further, in the embodiment shown in FIG. 1, the pin 12 is provided with strength enough to be sheared when the load torque T exceeds a predetermined value, so that the load torque T of a predetermined value or more is transmitted. When the pin 12 is sheared, the cage 8 is released from the restraint, so that the planet roller 6 is driven by the drive shaft 10.
Even if the pulley 1 rotates, the rotation is not transmitted to the driven roller 7 and the drive shaft 10. Therefore, the pin 12 and the hole that passes through it function as a kind of safety device in the planetary roller transmission mechanism 11.

As an alternative to the safety device consisting of the pin 12 and the hole in the embodiment of FIG. 1, if a mechanism as shown in FIG. 3 is applied to the planetary roller transmission mechanism 11 of FIG. 1, another structure of the planetary roller transmission mechanism is obtained. Examples can be constructed. In the safety device 13 shown in FIG. 3, a spring 16 supported by a stopper 15 fixed in a hole 14 of the boss portion 2.
And a recess 17 formed in a part of the cylindrical surface of the cage 8.
The ball 18 that engages with is elastically supported by a spring 16. Although not shown, it is convenient to provide a relatively shallow circumferential groove on the same plane as the circumferential recess 17 of the cage 8. In this case, when the load torque T transmitted by the planetary roller transmission mechanism exceeds a predetermined value, the ball 1
8 comes out of the recess 17 against the spring 16 and rolls in the circumferential groove as it is, so that the retainer 8 is unconstrained by the boss portion 2 and the retainer 8 is freely rotated. Since the planetary roller 6 revolves freely, the rotation of the pulley 1 is not transmitted to the driven roller 7. Therefore, the safety device 13 shown in FIG. 3 can prevent the generation of an excessive load torque T equal to or more than a predetermined value, like the pin 12 of FIG.

FIG. 4 shows an embodiment in which the friction transmission with a torque detecting function according to the present invention as shown in FIG. 1 is connected to a compressor with a continuously variable transmission. In this type of compressor, the discharge capacity of the pressurized fluid can be freely changed by continuously changing the driving speed of the compressor by a continuously variable transmission. It is suitable for use as a refrigerant compressor. In FIG. 4, 19 is a vane type positive displacement refrigerant compressor for a vehicle air conditioner, 20 is several planetary friction wheels 21, 1 ring 22, 1 input friction wheel 23 and 1 output friction wheel. The friction type continuously variable transmission of the type engaged with the vehicle 24 is shown. In this case, the refrigerant circulating in the refrigeration cycle of the air conditioner contains lubricating oil, and the refrigerant is sucked into the refrigerant compressor 19 through the inside of the friction continuously variable transmission 20 to lubricate the refrigerant compressor 19. Not only the friction engagement portion such as the friction wheel inside the friction type continuously variable transmission 20 for driving the same is also lubricated and cooled.

The suction chamber of the compressor 19 also serves as the transmission chamber 25 of the continuously variable transmission 20, and the refrigerant containing the lubricating oil returning from the evaporator in the refrigerating cycle of the air conditioner (not shown) contains the return port 26 in the upper portion. The lubricating oil is sucked into the transmission chamber 25 from the inside of the transmission chamber 25, and the lubricating oil is absorbed in various parts of the continuously variable transmission 20, such as the speed change ring 22 and the friction wheels 23 and 24, which are engaged with the planetary friction wheel 21 as described later. Lubricate and cool the friction engagement surface. The friction engagement portion of the continuously variable transmission 20 is lubricated and cooled by the lubricating oil contained in the low-temperature, low-pressure return refrigerant, so that seizure of the friction engagement portion is prevented. Refrigerant and lubricating oil are introduced into the compressor 1 from the suction port 28 that opens in the partition wall 27.
9, the gaseous refrigerant is compressed and discharged to a condenser of a refrigeration cycle (not shown).
At that time, the lubricating oil contained in the refrigerant also lubricates the sliding portion of the compressor 19 such as a vane, and the compressor 1
Prevent the seizure of 9.

A cam disk 29 is supported by a radial bearing and a thrust bearing provided on the hub of the input friction wheel 23, and an output rotation detecting ring 30 is provided on the right end surface thereof.
The output disk 31 attached to the input shaft 34 of the compressor 19 is connected by bolts with the compressor in between. Further, the cam disk 29 supports the output friction wheel 24 from the rear via a thrust generating cam mechanism 32. The output friction wheel 24 is loosely fitted onto the cylindrical portion of the cam disc 29 so as to be rotatable relative to it, and as the relative rotation angle with respect to the cam disc 29 becomes larger, the thrust generating cam mechanism 3 is provided.
2 is strongly pushed forward by the axial direction, and not only the frictional pressure contact force between the plurality of planetary friction wheels 21 and the output friction wheel 24, but also the frictional pressure contact force between them and the input friction wheel 23 and the speed change ring 22. Also has the effect of increasing according to the load torque.

By the carrier 33 which can freely rotate between the input friction wheel 23 and the output friction wheel 24, the rotational axes of several planetary friction wheels 21 are equidistantly arranged on the same circumference.
Further, they are supported so as to form the same angle with respect to the drive shaft 10, and a common transmission ring 22 is frictionally engaged with each conical friction surface of these planetary friction wheels 21. Although the ring 22 is prevented from rotating, it can be axially adjusted by the ring holder 35, so that the speed change ring 2 on the conical friction surface of each planetary friction wheel 21 can be adjusted.
The effective radius of the engagement point with 2 changes all at once. The position of the ring holder 35 is continuously adjusted by the transmission motor 36. The input friction wheel 23 is simultaneously frictionally engaged with the hourglass-shaped friction surface formed on the base of each planetary friction wheel 21, and the output friction wheel 24 is provided on the disk-shaped friction surface corresponding to the conical bottom surface. At the same time, they are frictionally engaged.

In the operating state, the pulley 1 of the friction transmission device 37 with a torque detecting function of the present invention as in the embodiment of FIG. 1 is driven by a vehicle engine (not shown) via a belt.
Is driven to rotate, its output rotation causes the drive shaft 10 to rotate.
The input friction wheel 23, which is integrated with, rotates, and the rotation is extracted to the output friction wheel 24 by rolling the plurality of planetary friction wheels 21 along the stationary transmission ring 22. If the rotational speed of the input friction wheel 23 is constant, the rotational speed of the output friction wheel 24 depends on the axial position of the transmission ring 22 positioned by the ring holder 35. Therefore, if the ring holder 35 and the speed change ring 22 are moved in the axial direction by the control rotation of the speed change motor 36, the rotation speed of the output friction wheel 24 changes continuously. On the contrary, even when the rotational speed of the input friction wheel 23 changes together with the drive shaft 10 due to a large change in the driving rotational speed of the pulley 1 as when driven by an automobile engine, the shaft of the ring 22 is changed. If the directional position is adjusted accordingly, the rotation speed of the input shaft 34 of the compressor 19 can be maintained substantially constant. Due to this action, the refrigerant compressor 19 provided with the friction type continuously variable transmission 20 always compresses and discharges the required flow rate of the refrigerant even if the engine speed significantly changes according to the running state of the vehicle. Therefore, the air conditioning capacity can be controlled ideally.

The structure of a control unit that can be used in the transmission system as illustrated in FIG. 4 is shown by the block diagram of FIG. The input rotation speed detection sensor 50 is for measuring the input rotation speed N _in of the pulley 1, and is an arbitrary rotation portion from the prime mover such as an automobile engine to the pulley 1 of the friction transmission device 37 with a torque detection function. It is provided at the position. A position facing the side surface of the pulley 1 is a suitable position. If the input rotation speed detection sensor 50 is provided on the side surface of the drive pulley connected to the pulley 1 by a belt (not shown), the detected value is multiplied by the speed ratio determined by the ratio of the diameters of the pulleys. As a result, the rotation speed of the pulley 1 is obtained. As the main body of the rotation speed sensor, various types such as an optical type and a magnetic type have been conventionally known, and therefore a detailed description thereof will be omitted here.

The output rotation speed detection sensor 51 is for measuring the output rotation speed N _out ^' of the friction transmission 37 taken out to the drive shaft 10, and the position where it is installed is the following rotation from the driven roller 7. It will be a part. A position facing the back surface of the input friction wheel 23 is a suitable position. In the system of FIG. 4, since the output rotation detection ring 30 for detecting the output rotation speed thereof is already provided inside the friction type continuously variable transmission 20, it is not shown provided for it. The output rotation speed detection sensor can be commonly used as the output rotation speed detection sensor 51.

The output rotation detecting ring 30 shown in FIG.
Is a crown-shaped metal disc having concave and convex notches around, and a coil constituting a magnetic pickup (not shown) fixedly installed near a part of the periphery is an output rotation detection ring. Since the electric pulse corresponding to the unevenness is generated when passing through the unevenness around 30, the number of pulses passing within a predetermined time is counted, or the number of clock pulses counted in one pulse interval is used. , Output rotation detection ring 3 of friction type continuously variable transmission 20
0, and therefore the number of revolutions of the input shaft 34 of the compressor 19 can be detected. The friction continuously variable transmission 20 is divided by the gear ratio currently shown to obtain the drive shaft 10
It is possible to determine the actual rotation speed of the output speed, that is, the output rotation speed N _out ^' .

The values detected by the input rotation speed detection sensor 50 and the output rotation speed detection sensor 51 are processed by the input rotation speed detection circuit 52 and the output rotation speed detection circuit 53, respectively, to obtain the input rotation speed N _in and the output rotation speed N. _out ^' is calculated. As described above, the calculation for correcting the detected value by the gear ratio or the like can be performed in this process. The calculated input rotation speed N _in and output rotation speed N _out ^' are input to the slip ratio calculation circuit 54, and the slip ratio S is calculated by substituting these values into the equation (1). .
The slip ratio S is further input to the torque detection circuit 55, and the load torque T of the friction transmission 37 is detected by collating the map as illustrated in FIG.

As described above, since the value of the load torque T is calculated from the slip ratio S of the friction transmission device 37, if the output rotation speed detection sensor 51 is the output rotation detection ring 30 of the friction type continuously variable transmission 20. When using, the friction type continuously variable transmission 20 with respect to the slip ratio S of the friction transmission 37 is used.
Since the slip ratio of 1 is detected, the map as shown in FIG. 2 needs to take that into consideration. However, in this case, there is also an advantage that it is possible to simultaneously detect the occurrence of abnormal slip in the friction type continuously variable transmission 20.

In this way, the load torque T obtained from the slip ratio S of the friction transmission 37 with the torque detecting function is obtained.
When the value of is within a predetermined normal range, the series of transmission systems continues to operate, but the refrigerant compressor 19
When a trouble occurs in the friction type continuously variable transmission 20 or the like, the slip ratio S of the friction transmission 37 increases, and when the value of the load torque T calculated from the slip ratio S exceeds a predetermined value,
In the case of the system of FIG. 4, a signal is output from the torque detection circuit 55 to the transmission control circuit 56, and the transmission motor is controlled and driven to move the transmission ring 22 in the axial direction. The gear ratio of 20 is changed to reduce the rotation of the input shaft 34 of the compressor to a safe range, or the gear ratio is set to zero to stop the rotation of the input shaft 34.

In the present invention, the friction type continuously variable transmission 20 is used.
Instead of this, it is possible to use another type of transmission, an electromagnetic clutch, or the like, and a refrigerant compressor that can change the discharge capacity without using the transmission or the like is used as a friction transmission device 37 with a torque detection function. In the case where it is directly connected to the prime mover via only, the discharge capacity is reduced or made zero by the signal output from the torque detection circuit 55. As described above, the present invention does not make it essential to provide the friction type continuously variable transmission 20, and therefore, in short, the load torque T is excessive from the detected value of the slip ratio S of the friction transmission with a torque detection function. When it is detected that the above condition has been detected, any controllable means that can reduce the load torque T to a value that does not hinder as a result may be operated.

[0029]

According to the friction transmission device with a torque detecting function of the present invention, the magnitude of the load torque can be detected in real time by an extremely simple means. Therefore, when the load torque becomes excessive, the load is immediately increased. It is possible to take measures such that the torque T is reduced to a value that does not interfere. The friction transmission device with a torque detection function has a simple structure, which does not increase the size or complexity of the transmission system, and the cost increase is relatively small. In addition, since a simple safety device can be incorporated in the friction transmission with torque detection function, the transmission can be cut off when an excessive load torque occurs to prevent damage to related equipment. it can.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a friction transmission device with a torque detecting function of the present invention.

FIG. 2 is a diagram illustrating a relationship between a slip ratio S and a load torque T.

FIG. 3 is an enlarged sectional view showing a part of another embodiment of the friction transmission device with a torque detection function of the present invention.

FIG. 4 is a vertical cross-sectional front view showing a case where the friction transmission device with a torque detection function shown in FIG. 1 is connected to a compressor with a continuously variable transmission.

FIG. 5 is a block diagram illustrating a configuration of a control device related to the present invention.

[Explanation of Codes] 1 ... Pulley 5 ... Friction surface 6 ... Planetary roller 7 ... Following roller 8 ... Cage 10 ... Drive shaft 11 ... Friction type planetary roller transmission mechanism 12 ... Pin 13 ... Safety device 19 ... Refrigerant compressor 20 ... friction type continuously variable transmission 21 ... planetary friction wheel 22 ... speed change ring 23 ... input friction wheel 24 ... output friction wheel 25 ... transmission chamber 30 ... output rotation detection ring 32 ... cam mechanism 34 ... compressor input shaft 36 ... transmission motor 37 ... friction transmission device with torque detection function 50 ... input rotation speed detection sensor 51 ... output rotation speed detection sensor 54 ... slip ratio calculation circuit 55 ... torque detection circuit

Claims (2)

[Claims] 1. A friction transmission device inserted in the middle of a series of transmission systems from a prime mover to a driven-side rotating machine,
An input rotation speed detection sensor that detects the rotation speed of the drive side of the friction transmission, an output rotation speed detection sensor that also detects the rotation speed of the driven side, the input rotation speed detection sensor and the output rotation speed detection sensor. Calculating means for calculating the slip ratio of the friction transmission device from the detected value, and calculating means for calculating the load torque of the friction transmission device from the slip ratio, and the calculating means outputs a signal indicating the generation of the load torque of a predetermined value or more. A friction transmission device with a torque detection function, comprising: a control unit that activates a unit that can reduce the load torque. 2. The friction transmission device comprises a planetary roller transmission mechanism, and means provided to prevent rotation of a cage supporting the planetary roller of the planetary roller transmission mechanism in a normal state are provided. The friction transmission device with a torque detecting function according to claim 1, which also functions as a safety device of the transmission system.